url
stringlengths 16
775
| text
stringlengths 100
1.02M
| date
timestamp[s] | metadata
stringlengths 1.07k
1.1k
|
|---|---|---|---|
https://indico.fnal.gov/event/15949/contributions/34888/
|
Indico search will be reestablished in the next version upgrade of the software: https://getindico.io/roadmap/
# 36th Annual International Symposium on Lattice Field Theory
22-28 July 2018
Kellogg Hotel and Conference Center
EST timezone
## The large-mass regime of confining but nearly conformal gauge theories
Jul 26, 2018, 11:20 AM
20m
104 (Kellogg Hotel and Conference Center)
### 104
#### Kellogg Hotel and Conference Center
219 S Harrison Rd, East Lansing, MI 48824
Physics Beyond the Standard Model
### Speaker
Prof. Maarten Golterman (San Francisco State University)
### Description
We apply a recently developed dilaton-pion effective field theory for asymptotically free gauge theories near the conformal window to the SU(3) gauge theory with $N_f=8$ fermions in the fundamental representation. Numerical data for this theory suggests the existence of a large-mass regime, where the fermion mass is not small but nevertheless the effective theory is applicable because of the parametric proximity of the conformal window. In this regime, we find that the mass dependence of hadronic quantities is similar to that of a a mass-deformed conformal theory, so that distinguishing infrared conformality from confinement requires the study of subleading effects.
### Primary author
Prof. Maarten Golterman (San Francisco State University)
### Co-author
Dr Yigal Shamir (Tel Aviv University)
Slides
| 2021-10-27T03:15:13 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3539280593395233, "perplexity": 5181.739555718234}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323588053.38/warc/CC-MAIN-20211027022823-20211027052823-00018.warc.gz"}
|
http://ocw.usu.edu/Electrical_and_Computer_Engineering/Stochastic_Processes/lec3_2.html
|
##### Personal tools
•
You are here: Home Random Vectors
# Random Vectors
##### Document Actions
Vectors :: Covariance :: Functions :: Application :: Markov Model
## Covariance
Suppose and (that is, and are random vectors of dimension and , respectively).
Note: is frequently used as a symbol to denote covariance. It should not be confused with a summation sign, and is usually clear from context.
Property:
If is and is and and then
is called the covariance of .'' It is a symmetric matrix, non-negative definite (or positive semidefinite), and thus has all non-negative eigenvalues.
If are mutually uncorrelated then
where
Suppose we partition of dimensions as
of and elements, respectively. let
where and . Similarly,
where
or, in general,
Copyright 2008, by the Contributing Authors. Cite/attribute Resource . admin. (2006, May 31). Random Vectors. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: http://ocw.usu.edu/Electrical_and_Computer_Engineering/Stochastic_Processes/lec3_2.html. This work is licensed under a Creative Commons License
| 2017-12-12T14:17:43 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.860393226146698, "perplexity": 5616.461730761212}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948517181.32/warc/CC-MAIN-20171212134318-20171212154318-00418.warc.gz"}
|
https://www.pnnl.gov/news-media/pnnl-collaborators-receive-new-funding-explore-enzyme-environment
|
October 26, 2020
Staff Accomplishment
## PNNL, Collaborators Receive New Funding to Explore Enzyme Environment
$1.7 million grant from NIH extends fundamental research into drivers of catalytic bias Left to right: Under a new grant from NIH, collaborators Simone Raugei at PNNL, John Peters at WSU, and David Mulder at NREL will continue fundamental research into the drivers of catalytic bias in enzyme reactions. Compilation by Shannon Colson | PNNL A new$1.7 million grant from the National Institutes of Health (NIH) continues important research into the innerand outerworkings of enzymes.
Awarded to a research team from Washington State University (WSU), Pacific Northwest National Laboratory (PNNL), and the National Renewable Energy Laboratory (NREL), the new funding builds on the team’s recent discovery related to catalytic bias in enzyme reactions. The research showed that the protein environment around the catalytic core of [FeFe] hydrogenases from the microbe Clostridium pasteurianum was responsible for shifting the direction and speed of the enzyme’s catalytic reaction.
The new project furthers that research to try and narrow down just what determines the factors responsible for increasing the speed of the reaction one way or the other.
John Peters, a professor at WSU, PNNL computational scientist Simone Raugei, and David Mulder, a staff scientist at NREL, will work together on the theoretical and experimental aspects of the four-year research effort. The collaboration for NIH builds on years of research sponsored by the U.S. Department of Energy’s Biological and Electron Transfer and Catalysis Energy Frontier Research Center, led by Peters.
## History of teaming and results
Peters and Raugei hold joint appointments at each other’s institution and have teamed closely on fundamental research related to the function of enzymes over the years. The two scientists credit the long-term arrangement and complementary strengths to the effectiveness of their proposal and the speed at which the award was granted.
“It is pretty rare for a first-time proposal submission to be awarded right out of the gate,” said Peters. “Most proposals to NIH are renewals or go through several revisions. Our new project was awarded with no revisions.”
Raugei agreed, saying that in addition to their history of productive research, the award proves the team had a “compelling idea and tractable system for doing the research.”
“We showed we have a simple model to test complex phenomena and solid preliminary data,” said Raugei.
The scientists believe their concepts about catalytic bias in [FeFe] hydrogenases may be general enough to be applied to other systems similar to enzymes. The team hopes to demonstrate that possibility with the new research.
“These are first principle questions about catalytic bias in redox enzymes and the factors that regulate biological processes,” said Raugei. “Tailoring the environment around a catalytic reaction has profound implications for new catalytic processes and materials.”
Published: October 26, 2020
| 2020-12-02T04:35:57 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.21671873331069946, "perplexity": 3803.7360081465517}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141686635.62/warc/CC-MAIN-20201202021743-20201202051743-00127.warc.gz"}
|
https://www.usgs.gov/media/images/decay-chain-uranium-238
|
# Decay chain for uranium-238
## Detailed Description
Decay chain for uranium-238 progressing through a series of intermediate daughter products (including 234U and 230Th) by alpha and beta decay finally resulting in stable 206Pb.
## Details
Image Dimensions: 2350 x 1502
Location Taken: US
## Credits
Faure, G. and Mensing, T.M., 2005, Isotopes – Principles and Applications, third edition. John Wiley & Sons, New York, 897 p
Source:
Faure, G. and Mensing, T.M., 2005, Isotopes – Principles and Applications, third edition. John Wiley & Sons, New York, 897 p
| 2019-10-17T07:36:37 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8304314613342285, "perplexity": 6553.639435721079}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986673250.23/warc/CC-MAIN-20191017073050-20191017100550-00260.warc.gz"}
|
http://www.itl.nist.gov/div898/handbook/mpc/section3/mpc37.htm
|
2. Measurement Process Characterization
2.3. Calibration
## Instrument control for linear calibration
Purpose The purpose of the control program is to guarantee that the calibration of an instrument does not degrade over time.
Approach This is accomplished by exercising quality control on the instrument's output in much the same way that quality control is exercised on components in a process using a modification of the Shewhart control chart.
Check standards needed for the control program For linear calibration, it is sufficient to control the end-points and the middle of the calibration interval to ensure that the instrument does not drift out of calibration. Therefore, check standards are required at three points; namely,
• at the lower-end of the regime
• at the mid-range of the regime
• at the upper-end of the regime
Data collection One measurement is needed on each check standard for each checking period. It is advisable to start by making control measurements at the start of each day or as often as experience dictates. The time between checks can be lengthened if the instrument continues to stay in control.
Definition of control value To conform to the notation in the section on instrument corrections, $$X^*$$ denotes the known value of a standard, and $$X$$ denotes the measurement on the standard.
A control value is defined as the difference $$W = X^* - X$$ If the calibration is perfect, control values will be randomly distributed about zero and fall within appropriate upper and lower limits on a control chart.
Calculation of control limits The upper and lower control limits (Croarkin and Varner)) are, respectively,
$$l_{upper} = +\frac{s}{\hat{b}}t_{\alpha/2}^{*}(\nu)$$ $$l_{lower} = -\frac{s}{\hat{b}}t_{\alpha/2}^{*}(\nu)$$
where $${\large s}$$ is the residual standard deviation of the fit from the calibration experiment, and $$\hat{b}$$ is the estimated slope of the linear calibration curve.
Values t* The critical value, $$t_{\alpha/2}^{*}$$, can be found in the t*table; $$\nu$$ is the degrees of freedom for the residual standard deviation; and $$\alpha$$ is equal to 0.05.
Determining t* For the case where $$\alpha = 0.05$$ and $$\nu = 38$$, the critical value of the $$t^*$$ statistic is 2.497575.
R code and Dataplot code can be used to determine $$t^*$$ critical values using a standard $$t$$-table for the $$\zeta$$ quantile and $$\nu$$ degrees of freedom where $$\zeta$$ is computed as $$\zeta = \frac{1}{2} \left[ 1 - e^{\frac{\ln (1-\alpha)}{m}} \right]$$ where m is the number of check standards.
Sensitivity to departure from linearity If $$l_{lower} \le W \le l_{upper}$$ the instrument is in statistical control. Statistical control in this context implies not only that measurements are repeatable within certain limits but also that instrument response remains linear. The test is sensitive to departures from linearity.
Control chart for a system corrected by a linear calibration curve An example of measurements of line widths on photomask standards, made with an optical imaging system and corrected by a linear calibration curve, are shown as an example. The three control measurements were made on reference standards with values at the lower, mid-point, and upper end of the calibration interval.
| 2017-10-21T04:41:07 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7715051770210266, "perplexity": 697.141872477453}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187824570.79/warc/CC-MAIN-20171021043111-20171021063111-00045.warc.gz"}
|
https://par.nsf.gov/biblio/10349772-discovery-cwise-j052306-extreme-subdwarf-candidate
|
Discovery of CWISE J052306.42−015355.4, an Extreme T Subdwarf Candidate
Abstract We present the discovery of CWISE J052306.42−015355.4, which was found as a faint, significant proper-motion object (0.″52 ± 0.″08 yr −1 ) using machine-learning tools on the unWISE re-processing of time series images from the Wide-field Infrared Survey Explorer. Using the CatWISE2020 W1 and W2 magnitudes along with a J -band detection from the VISTA Hemisphere Survey, the location of CWISE J052306.42−015355.4 on the W1 − W2 versus J − W2 diagram best matches that of other known, or suspected, extreme T subdwarfs. As there is currently very little knowledge concerning extreme T subdwarfs we estimate a rough distance of ≤68 pc, which results in a tangential velocity of ≤167 km s −1 , both of which are tentative. A measured parallax is greatly needed to test these values. We also estimate a metallicity of −1.5 < [M/H] < −0.5 using theoretical predictions.
Authors:
; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10349772
Journal Name:
The Astronomical Journal
Volume:
163
Issue:
2
Page Range or eLocation-ID:
47
ISSN:
0004-6256
National Science Foundation
1. ##### Abstract
The COVID-19 pandemic has dramatically altered family life in the United States. Over the long duration of the pandemic, parents had to adapt to shifting work conditions, virtual schooling, the closure of daycare facilities, and the stress of not only managing households without domestic and care supports but also worrying that family members may contract the novel coronavirus. Reports early in the pandemic suggest that these burdens have fallen disproportionately on mothers, creating concerns about the long-term implications of the pandemic for gender inequality and mothers’ well-being. Nevertheless, less is known about how parents’ engagement in domestic labor and paid work has changed throughout the pandemic, what factors may be driving these changes, and what the long-term consequences of the pandemic may be for the gendered division of labor and gender inequality more generally. <br /><br />The Study on U.S. Parents’ Divisions of Labor During COVID-19 (SPDLC) collects longitudinal survey data from partnered U.S. parents that can be used to assess changes in parents’ divisions of domestic labor, divisions of paid labor, and well-being throughout and after the COVID-19 pandemic. The goal of SPDLC is to understand both the short- and long-term impacts of the pandemic for the genderedMore>>
2. Abstract
We present new empirical infrared period–luminosity–metallicity (PLZ) and period–Wesenheit–metallicity (PWZ) relations for RR Lyae based on the latest Gaia Early Data Release 3 (EDR3) parallaxes. The relations are provided in the Wide-field Infrared Survey Explorer (WISE) W1 and W2 bands, as well as in the W(W1,V− W1) and W(W2,V− W2) Wesenheit magnitudes. The relations are calibrated using a very large sample of Galactic halo field RR Lyrae stars with homogeneous spectroscopic [Fe/H] abundances (over 1000 stars in the W1 band), covering a broad range of metallicities (−2.5 ≲ [Fe/H] ≲ 0.0). We test the performance of our PLZ and PWZ relations by determining the distance moduli of both galactic and extragalactic stellar associations: the Sculptor dwarf spheroidal galaxy in the Local Group (finding$μ¯0=19.47±0.06$), the Galactic globular clusters M4 ($μ¯0=11.16±0.05$), and the Reticulum globular cluster in the Large Magellanic Cloud ($μ¯0=18.23±0.06$). The distance moduli determined through all our relations are internally self-consistent (within ≲0.05 mag) but are systematically smaller (by ∼2–3σ) than previous literature measurements taken from a variety of methods/anchors. However, a comparison with similar recent RR Lyrae empirical relations anchored with EDR3 likewise shows, to varyingmore »
3. ABSTRACT
Extremely red quasars (ERQs) are an interesting sample of quasars in the Baryon Oscillation Spectroscopic Sample (BOSS) in the redshift range of 2.0–3.4 and have extreme red colours of i − W3 ≥ 4.6. Core ERQs have strong C iv emission lines with rest equivalent width of ≥100 Å. Many core ERQs also have C iv line profiles with peculiar boxy shapes which distinguish them from normal blue quasars. We show, using a combination of kernel density estimation and local outlier factor analyses on a space of the i − W3 colour, C iv rest equivalent width and line kurtosis, that core ERQs likely represent a separate population rather than a smooth transition between normal blue quasars and the quasars in the tail of the colour-REW distribution. We apply our analyses to find new criteria for selecting ERQs in this 3D parameter space. Our final selection produces 133 quasars, which are three times more likely to have a visually verified C iv broad absorption line feature than the previous core ERQ sample. We further show that our newly selected sample are extreme objects in the intersection of the WISE AGN catalogue with the MILLIQUAS quasar catalogue in the colour–colour space of (W1 − W2, W2 − W3). Thismore »
4. Abstract We present PHANGS–ALMA, the first survey to map CO J = 2 → 1 line emission at ∼1″ ∼100 pc spatial resolution from a representative sample of 90 nearby ( d ≲ 20 Mpc) galaxies that lie on or near the z = 0 “main sequence” of star-forming galaxies. CO line emission traces the bulk distribution of molecular gas, which is the cold, star-forming phase of the interstellar medium. At the resolution achieved by PHANGS–ALMA, each beam reaches the size of a typical individual giant molecular cloud, so that these data can be used to measure the demographics, life cycle, and physical state of molecular clouds across the population of galaxies where the majority of stars form at z = 0. This paper describes the scientific motivation and background for the survey, sample selection, global properties of the targets, Atacama Large Millimeter/submillimeter Array (ALMA) observations, and characteristics of the delivered data and derived data products. As the ALMA sample serves as the parent sample for parallel surveys with MUSE on the Very Large Telescope, the Hubble Space Telescope, AstroSat, the Very Large Array, and other facilities, we include a detailed discussion of the sample selection. We detail the estimationmore »
5. Abstract Nuclear rings are excellent laboratories for studying intense star formation. We present results from a study of nuclear star-forming rings in five nearby normal galaxies from the Star Formation in Radio Survey (SFRS) and four local LIRGs from the Great Observatories All-sky LIRG Survey at sub-kiloparsec resolutions using Very Large Array high-frequency radio continuum observations. We find that nuclear ring star formation (NRSF) contributes 49%–60% of the total star formation of the LIRGs, compared to 7%–40% for the normal galaxies. We characterize a total of 57 individual star-forming regions in these rings, and find that with measured sizes of 10–200 pc, NRSF regions in the LIRGs have star formation rate (SFR) and Σ SFR up to 1.7 M ⊙ yr −1 and 402 M ⊙ yr −1 kpc −2 , respectively, which are about 10 times higher than in NRSF regions in the normal galaxies with similar sizes, and comparable to lensed high- z star-forming regions. At ∼100–300 pc scales, we estimate low contributions (<50%) of thermal free–free emission to total radio continuum emission at 33 GHz in the NRSF regions in the LIRGs, but large variations possibly exist at smaller physical scales. Finally, using archival sub-kiloparsec resolution COmore »
| 2023-03-31T05:53:20 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 3, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5647239685058594, "perplexity": 4888.0379793181755}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949573.84/warc/CC-MAIN-20230331051439-20230331081439-00346.warc.gz"}
|
https://zbmath.org/authors/?q=ai%3Amalaguti.luisa
|
# zbMATH — the first resource for mathematics
## Malaguti, Luisa
Compute Distance To:
Author ID: malaguti.luisa Published as: Malaguti, L.; Malaguti, Luisa Homepage: http://personale.unimore.it/rubrica/dettaglio/malaguti External Links: MGP · Wikidata
Documents Indexed: 68 Publications since 1987
all top 5
#### Co-Authors
5 single-authored 20 Taddei, Valentina 16 Marcelli, Cristina 12 Andres, Jan 12 Benedetti, Irene 8 Matucci, Serena 7 Corli, Andrea 5 Pavlačková, Martina 3 Cecchini, Simone 3 Nguyen Van Loi 2 Di Ruvo, Lorenzo 2 Kožušníková, Martina 2 Maini, Philip Kumar 1 Berti, Diego 1 Gavioli, Andrea 1 Lomtatidze, A. G. 1 Lomtatidze, Alexander 1 Makarenkov, Oleg Yuryĭovych 1 Nistri, Paolo 1 Obukhovskiĭ, Valeriĭ Vladimirovich 1 Partsvania, Nino 1 Pavlačová, Martina 1 Perrotta, Stefania 1 Řehák, Pavel 1 Rosini, Massimiliano Daniele 1 Rubbioni, Paola 1 Ruggerini, Stefano 1 Rykaczewski, Krzysztof 1 Torricelli, Costanza 1 Vrabie, Ioan I. 1 Yoshii, Kentarou
all top 5
#### Serials
5 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 4 Journal of Mathematical Analysis and Applications 3 Dynamic Systems and Applications 3 Discrete and Continuous Dynamical Systems 3 Electronic Journal of Qualitative Theory of Differential Equations 3 Boundary Value Problems 2 Journal of Differential Equations 2 Rendiconti dell’Istituto di Matematica dell’Università di Trieste 2 Zeitschrift für Analysis und ihre Anwendungen 2 Atti del Seminario Matematico e Fisico dell’Università di Modena 2 Topological Methods in Nonlinear Analysis 2 Differential Equations and Dynamical Systems 2 Abstract and Applied Analysis 2 Advanced Nonlinear Studies 1 Computers & Mathematics with Applications 1 Nonlinearity 1 ZAMP. Zeitschrift für angewandte Mathematik und Physik 1 Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica 1 Annali di Matematica Pura ed Applicata. Serie Quarta 1 Archivum Mathematicum 1 Mathematische Nachrichten 1 Portugaliae Mathematica 1 Mathematica Bohemica 1 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 1 Bollettino della Unione Matemàtica Italiana. Serie VII. B 1 Electronic Journal of Differential Equations (EJDE) 1 Georgian Mathematical Journal 1 NoDEA. Nonlinear Differential Equations and Applications 1 Journal of Convex Analysis 1 Advances in Differential Equations 1 Communications in Contemporary Mathematics 1 Discrete and Continuous Dynamical Systems. Series B 1 Decisions in Economics and Finance 1 Communications on Pure and Applied Analysis 1 Fixed Point Theory 1 Mediterranean Journal of Mathematics 1 Dynamics of Partial Differential Equations 1 Networks and Heterogeneous Media 1 Applied Mathematics & Information Sciences 1 Set-Valued and Variational Analysis
all top 5
#### Fields
49 Ordinary differential equations (34-XX) 25 Partial differential equations (35-XX) 18 Operator theory (47-XX) 7 Biology and other natural sciences (92-XX) 4 Systems theory; control (93-XX) 3 Calculus of variations and optimal control; optimization (49-XX) 3 Classical thermodynamics, heat transfer (80-XX) 2 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 1 Dynamical systems and ergodic theory (37-XX) 1 Difference and functional equations (39-XX) 1 General topology (54-XX)
#### Citations contained in zbMATH Open
53 Publications have been cited 288 times in 192 Documents Cited by Year
On a nonlocal boundary value problem for second-order nonlinear singular differential equations. Zbl 0967.34011
Lomtatidze, A.; Malaguti, L.
2000
Travelling wavefronts in reaction-diffusion equations with convection effects and non-regular terms. Zbl 1016.35036
Malaguti, Luisa; Marcelli, Cristina
2002
Nonlocal semilinear evolution equations without strong compactness: theory and applications. Zbl 1288.34056
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2013
Sharp profiles in degenerate and doubly degenerate Fisher-KPP equations. Zbl 1042.34056
Malaguti, Luisa; Marcelli, Cristina
2003
Semilinear evolution equations in abstract spaces and applications. Zbl 1272.34084
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2012
On a two-point boundary value problem for the second order ordinary differential equations with singularities. Zbl 1027.34022
Lomtatidze, A.; Malaguti, L.
2003
On boundary value problems in Banach spaces. Zbl 1195.34091
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2009
Diffusion-aggregation processes with mono-stable reaction terms. Zbl 1116.35099
Maini, Philip K.; Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2006
Nonlocal problems for differential inclusions in Hilbert spaces. Zbl 1312.34097
Benedetti, I.; Loi, N. V.; Malaguti, L.
2014
Continuous dependence in front propagation of convective reaction-diffusion equations. Zbl 1213.35071
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2010
Semilinear differential inclusions via weak topologies. Zbl 1198.34109
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2010
Two-point b.v.p. for multivalued equations with weakly regular r.h.s. Zbl 1221.34161
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2011
On transitional solutions of second order nonlinear differential equations. Zbl 1140.34347
Malaguti, L.; Marcelli, C.; Partsvania, N.
2005
Front propagation in bistable reaction-diffusion-advection equation. Zbl 1101.35009
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2004
Traveling waves for degenerate diffusive equations on networks. Zbl 1374.35231
Corli, Andrea; di Ruvo, Lorenzo; Malaguti, Luisa; Rosini, Massimiliano D.
2017
Nonlocal diffusion second order partial differential equations. Zbl 1353.35297
Benedetti, I.; Loi, N. V.; Malaguti, L.; Taddei, V.
2017
Finite speed of propagation in monostable degenerate reaction-diffusion-convection equations. Zbl 1074.35056
Malaguti, Luisa; Marcelli, Cristina
2005
Floquet boundary value problems for differential inclusions: a bound sets approach. Zbl 0986.34012
Andres, J.; Malaguti, L.; Taddei, V.
2001
Viable solutions of differential inclusions with memory in Banach spaces. Zbl 0963.34059
Gavioli, A.; Malaguti, L.
2000
An approximation solvability method for nonlocal differential problems in Hilbert spaces. Zbl 1378.34083
Benedetti, Irene; van Loi, Nguyen; Malaguti, Luisa; Obukhovskii, Valeri
2017
Semilinear delay evolution equations with measures subjected to nonlocal initial conditions. Zbl 1409.34064
Benedetti, I.; Malaguti, L.; Taddei, V.; Vrabie, I. I.
2016
Aggregative movement and front propagation for bi-stable population models. Zbl 1135.92027
Maini, Philip K.; Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2007
A bounding functions approach to multivalued boundary value problems. Zbl 1126.34010
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2007
Bounded solutions of Carathéodory differential inclusions: a bound sets approach. Zbl 1036.34011
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2003
Existence of bounded trajectories via upper and lower solutions. Zbl 0979.34019
Malaguti, Luisa; Marcelli, Cristina
2000
Semi-wavefront solutions in models of collective movements with density-dependent diffusivity. Zbl 1365.35082
Corli, Andrea; Malaguti, Luisa
2016
Nonsmooth feedback controls of nonlocal dispersal models. Zbl 1351.92043
Malaguti, Luisa; Rubbioni, Paola
2016
On second-order boundary value problems in Banach spaces: a bound sets approach. Zbl 1242.34116
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2011
Strictly localized bounding functions for vector second-order boundary value problems. Zbl 1185.34016
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2009
Bound sets approach to boundary value problems for vector second-order differential inclusions. Zbl 1177.34015
Andres, Jan; Kožušníková, Martina; Malaguti, Luisa
2009
Monotone trajectories of differential inclusions in Banach spaces. Zbl 0877.34018
Malaguti, Luisa
1996
Sharp profiles in models of collective movements. Zbl 1373.35178
Corli, Andrea; di Ruvo, Lorenzo; Malaguti, Luisa
2017
A Scorza-Dragoni approach to second-order boundary value problems in abstract spaces. Zbl 1369.34083
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2012
Strictly localized bounding functions and Floquet boundary value problems. Zbl 1340.34215
Cecchini, Simone; Malaguti, Luisa; Taddei, Valentina
2011
Continuous dependence in front propagation for convective reaction-diffusion models with aggregative movements. Zbl 1252.35040
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2011
Asymptotic speed of propagation for Fisher-type degenerate reaction-diffusion-convection equations. Zbl 1227.35071
Malaguti, Luisa; Ruggerini, Stefano
2010
Viscous profiles in models of collective movement with negative diffusivity. Zbl 1415.35169
Corli, Andrea; Malaguti, Luisa
2019
Nonlocal solutions of parabolic equations with strongly elliptic differential operators. Zbl 1409.35119
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2019
Hartman-type conditions for multivalued Dirichlet problem in abstract spaces. Zbl 1345.34117
Pavlačková, Martina; Malaguti, Luisa; Andres, Jan
2015
Scorza-Dragoni approach to Dirichlet problem in Banach spaces. Zbl 1335.34091
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2014
Dirichlet problem in Banach spaces: the bound sets approach. Zbl 1321.34081
Andres, Jan; Malaguti, Luisa; Pavlačová, Martina
2013
Boundary value problem for differential inclusions in Fréchet spaces with multiple solutions of the homogeneous problem. Zbl 1249.34171
Benedetti, I.; Malaguti, L.; Taddei, V
2011
Periodic solutions of semilinear multivalued and functional evolution equations in Banach spaces. Zbl 1210.34082
Cecchini, Simone; Malaguti, Luisa
2009
On the Floquet problem for second-order Marchaud differential systems. Zbl 1166.34003
Andres, Jan; Kožušníková, Martina; Malaguti, Luisa
2009
Bounded solutions and wavefronts for discrete dynamics. Zbl 1066.39019
Malaguti, L.; Řehák, P.; Taddei, V.
2004
A unifying approach to travelling wavefronts for reaction-diffusion equations arising from genetics and combustion models. Zbl 1048.35033
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2003
Existence and multiplicity of heteroclinic solutions for a non-autonomous boundary eigenvalue problem. Zbl 1054.34046
Malaguti, Luisa; Marcelli, Cristina
2003
Heteroclinic orbits in plane dynamical systems. Zbl 1090.34037
Malaguti, Luisa; Marcelli, Cristina
2002
A comparison-type approach for travelling fronts. Zbl 0964.35074
Malaguti, Luisa; Marcelli, Cristina
2000
Asymptotic properties of an ordinary differential equation via topological methods. Zbl 0921.34048
1998
Bounded solutions for a class of second order nonlinear differential equations. Zbl 0876.34037
Malaguti, Luisa
1995
Limit properties for solutions of a class of second order nonlinear differential equations. Zbl 0845.34043
Malaguti, Luisa
1995
Periodic solutions of the Lienard equation: bifurcation at the infinity and nonuniqueness. Zbl 0647.34038
Malaguti, Luisa
1987
Viscous profiles in models of collective movement with negative diffusivity. Zbl 1415.35169
Corli, Andrea; Malaguti, Luisa
2019
Nonlocal solutions of parabolic equations with strongly elliptic differential operators. Zbl 1409.35119
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2019
Traveling waves for degenerate diffusive equations on networks. Zbl 1374.35231
Corli, Andrea; di Ruvo, Lorenzo; Malaguti, Luisa; Rosini, Massimiliano D.
2017
Nonlocal diffusion second order partial differential equations. Zbl 1353.35297
Benedetti, I.; Loi, N. V.; Malaguti, L.; Taddei, V.
2017
An approximation solvability method for nonlocal differential problems in Hilbert spaces. Zbl 1378.34083
Benedetti, Irene; van Loi, Nguyen; Malaguti, Luisa; Obukhovskii, Valeri
2017
Sharp profiles in models of collective movements. Zbl 1373.35178
Corli, Andrea; di Ruvo, Lorenzo; Malaguti, Luisa
2017
Semilinear delay evolution equations with measures subjected to nonlocal initial conditions. Zbl 1409.34064
Benedetti, I.; Malaguti, L.; Taddei, V.; Vrabie, I. I.
2016
Semi-wavefront solutions in models of collective movements with density-dependent diffusivity. Zbl 1365.35082
Corli, Andrea; Malaguti, Luisa
2016
Nonsmooth feedback controls of nonlocal dispersal models. Zbl 1351.92043
Malaguti, Luisa; Rubbioni, Paola
2016
Hartman-type conditions for multivalued Dirichlet problem in abstract spaces. Zbl 1345.34117
Pavlačková, Martina; Malaguti, Luisa; Andres, Jan
2015
Nonlocal problems for differential inclusions in Hilbert spaces. Zbl 1312.34097
Benedetti, I.; Loi, N. V.; Malaguti, L.
2014
Scorza-Dragoni approach to Dirichlet problem in Banach spaces. Zbl 1335.34091
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2014
Nonlocal semilinear evolution equations without strong compactness: theory and applications. Zbl 1288.34056
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2013
Dirichlet problem in Banach spaces: the bound sets approach. Zbl 1321.34081
Andres, Jan; Malaguti, Luisa; Pavlačová, Martina
2013
Semilinear evolution equations in abstract spaces and applications. Zbl 1272.34084
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2012
A Scorza-Dragoni approach to second-order boundary value problems in abstract spaces. Zbl 1369.34083
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2012
Two-point b.v.p. for multivalued equations with weakly regular r.h.s. Zbl 1221.34161
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2011
On second-order boundary value problems in Banach spaces: a bound sets approach. Zbl 1242.34116
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2011
Strictly localized bounding functions and Floquet boundary value problems. Zbl 1340.34215
Cecchini, Simone; Malaguti, Luisa; Taddei, Valentina
2011
Continuous dependence in front propagation for convective reaction-diffusion models with aggregative movements. Zbl 1252.35040
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2011
Boundary value problem for differential inclusions in Fréchet spaces with multiple solutions of the homogeneous problem. Zbl 1249.34171
Benedetti, I.; Malaguti, L.; Taddei, V
2011
Continuous dependence in front propagation of convective reaction-diffusion equations. Zbl 1213.35071
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2010
Semilinear differential inclusions via weak topologies. Zbl 1198.34109
Benedetti, Irene; Malaguti, Luisa; Taddei, Valentina
2010
Asymptotic speed of propagation for Fisher-type degenerate reaction-diffusion-convection equations. Zbl 1227.35071
Malaguti, Luisa; Ruggerini, Stefano
2010
On boundary value problems in Banach spaces. Zbl 1195.34091
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2009
Strictly localized bounding functions for vector second-order boundary value problems. Zbl 1185.34016
Andres, Jan; Malaguti, Luisa; Pavlačková, Martina
2009
Bound sets approach to boundary value problems for vector second-order differential inclusions. Zbl 1177.34015
Andres, Jan; Kožušníková, Martina; Malaguti, Luisa
2009
Periodic solutions of semilinear multivalued and functional evolution equations in Banach spaces. Zbl 1210.34082
Cecchini, Simone; Malaguti, Luisa
2009
On the Floquet problem for second-order Marchaud differential systems. Zbl 1166.34003
Andres, Jan; Kožušníková, Martina; Malaguti, Luisa
2009
Aggregative movement and front propagation for bi-stable population models. Zbl 1135.92027
Maini, Philip K.; Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2007
A bounding functions approach to multivalued boundary value problems. Zbl 1126.34010
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2007
Diffusion-aggregation processes with mono-stable reaction terms. Zbl 1116.35099
Maini, Philip K.; Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2006
On transitional solutions of second order nonlinear differential equations. Zbl 1140.34347
Malaguti, L.; Marcelli, C.; Partsvania, N.
2005
Finite speed of propagation in monostable degenerate reaction-diffusion-convection equations. Zbl 1074.35056
Malaguti, Luisa; Marcelli, Cristina
2005
Front propagation in bistable reaction-diffusion-advection equation. Zbl 1101.35009
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2004
Bounded solutions and wavefronts for discrete dynamics. Zbl 1066.39019
Malaguti, L.; Řehák, P.; Taddei, V.
2004
Sharp profiles in degenerate and doubly degenerate Fisher-KPP equations. Zbl 1042.34056
Malaguti, Luisa; Marcelli, Cristina
2003
On a two-point boundary value problem for the second order ordinary differential equations with singularities. Zbl 1027.34022
Lomtatidze, A.; Malaguti, L.
2003
Bounded solutions of Carathéodory differential inclusions: a bound sets approach. Zbl 1036.34011
Andres, Jan; Malaguti, Luisa; Taddei, Valentina
2003
A unifying approach to travelling wavefronts for reaction-diffusion equations arising from genetics and combustion models. Zbl 1048.35033
Malaguti, Luisa; Marcelli, Cristina; Matucci, Serena
2003
Existence and multiplicity of heteroclinic solutions for a non-autonomous boundary eigenvalue problem. Zbl 1054.34046
Malaguti, Luisa; Marcelli, Cristina
2003
Travelling wavefronts in reaction-diffusion equations with convection effects and non-regular terms. Zbl 1016.35036
Malaguti, Luisa; Marcelli, Cristina
2002
Heteroclinic orbits in plane dynamical systems. Zbl 1090.34037
Malaguti, Luisa; Marcelli, Cristina
2002
Floquet boundary value problems for differential inclusions: a bound sets approach. Zbl 0986.34012
Andres, J.; Malaguti, L.; Taddei, V.
2001
On a nonlocal boundary value problem for second-order nonlinear singular differential equations. Zbl 0967.34011
Lomtatidze, A.; Malaguti, L.
2000
Viable solutions of differential inclusions with memory in Banach spaces. Zbl 0963.34059
Gavioli, A.; Malaguti, L.
2000
Existence of bounded trajectories via upper and lower solutions. Zbl 0979.34019
Malaguti, Luisa; Marcelli, Cristina
2000
A comparison-type approach for travelling fronts. Zbl 0964.35074
Malaguti, Luisa; Marcelli, Cristina
2000
Asymptotic properties of an ordinary differential equation via topological methods. Zbl 0921.34048
1998
Monotone trajectories of differential inclusions in Banach spaces. Zbl 0877.34018
Malaguti, Luisa
1996
Bounded solutions for a class of second order nonlinear differential equations. Zbl 0876.34037
Malaguti, Luisa
1995
Limit properties for solutions of a class of second order nonlinear differential equations. Zbl 0845.34043
Malaguti, Luisa
1995
Periodic solutions of the Lienard equation: bifurcation at the infinity and nonuniqueness. Zbl 0647.34038
Malaguti, Luisa
1987
all top 5
#### Cited by 271 Authors
29 Malaguti, Luisa 19 Benedetti, Irene 19 Taddei, Valentina 13 Ge, Weigao 9 Feng, Meiqiang 9 Zhang, Xuemei 8 Andres, Jan 7 Liu, Lishan 7 Marcelli, Cristina 7 Obukhovskiĭ, Valeriĭ Vladimirovich 6 Nguyen Van Loi 6 Wu, Yonghong 5 Kiguradze, Ivan Tarielovich 5 Liu, Zhenhai 4 Pavlačková, Martina 4 Rachůnková, Irena 3 Corli, Andrea 3 Di Ruvo, Lorenzo 3 Garrione, Maurizio 3 Lu, Liang 3 O’Regan, Donal 3 Staněk, Svatoslav 3 Weinmüller, Ewa B. 2 Agarwal, Ravi P. 2 Aitalioubrahim, Myelkebir 2 Balasuriya, Sanjeeva 2 Bao, Lianzhang 2 Burkotová, Jana 2 Cichoń, Mieczysław 2 Ding, Wei 2 Du, Yihong 2 Ibrahim, Ahmed Gamal 2 Kiguradze, Tariel I. 2 Kožušníková, Martina 2 Leyva, J. Francisco 2 Li, Hongdan 2 Li, Peiluan 2 Li, Wan-Tong 2 Li, Xiuwen 2 Liu, Yansheng 2 Matucci, Serena 2 Minhós, Feliz Manuel 2 Plaza, Ramón G. 2 Ramos, Higinio 2 Ruan, Shigui 2 Rufai, M. A. 2 Salem, Hussein A. H. 2 Sanchez, Luís 2 Vrabie, Ioan I. 2 Wang, Jinrong 2 Wang, Youyu 2 Yao, Huanmin 2 Yin, Jingxue 2 Zhang, Xingqiu 2 Zhang, Xinqiu 2 Zhou, Maolin 2 Zhou, Yong 1 Alfaro, Matthieu 1 Alizadeh, Mahdieh 1 Alves, Claudianor Oliveira 1 Aprahamian, Meline Onik 1 Arias, Margarita 1 Aslanov, Afgan 1 Bai, Yuzhen 1 Bataineh, A. Sami 1 Benchohra, Mouffak 1 Bisconti, Luca 1 Borsche, Raul 1 Bougoffa, Lazhar 1 Burlică, Monica-Dana 1 Caglar, Hikmet 1 Caglar, Nazan 1 Cai, Chen 1 Campos, Daniel G. 1 Campos, Juan 1 Cao, Junfei 1 Cardinali, Tiziana 1 Cârjă, Ovidiu 1 Carrião, Paulo Cesar 1 Cecchini, Simone 1 Chai, Guoqing 1 Chen, Tianlan 1 Cheng, Yi 1 Coclite, Giuseppe Maria 1 Coelho, Isabel 1 Cui, Yujun 1 Cuong, Pham Tuan 1 Diaz Diaz, Jesus Ildefonso 1 Donchev, Tzanko Donchev 1 Du, Bo 1 Faria, Luiz F. O. 1 Fedotov, Sergei P. 1 Fu, Dan 1 Fu, Yanli 1 Fura, Justyna 1 Galewski, Marek 1 Gao, Wenjie 1 Gavioli, Andrea 1 Gomes, José Maria 1 Gottwald, Georg A. ...and 171 more Authors
all top 5
#### Cited in 79 Serials
18 Journal of Mathematical Analysis and Applications 17 Boundary Value Problems 12 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 8 Journal of Differential Equations 7 Computers & Mathematics with Applications 7 Applied Mathematics and Computation 7 Advances in Difference Equations 6 Abstract and Applied Analysis 4 Journal of Mathematical Biology 4 Journal of Nonlinear Science and Applications 4 Journal of Function Spaces 3 Journal of Computational and Applied Mathematics 3 Applied Mathematics Letters 3 Topological Methods in Nonlinear Analysis 3 Discrete and Continuous Dynamical Systems 3 Fractional Calculus & Applied Analysis 3 Journal of Dynamical and Control Systems 3 Discrete and Continuous Dynamical Systems. Series B 3 Advanced Nonlinear Studies 3 Journal of Applied Mathematics and Computing 2 Mathematische Nachrichten 2 Numerical Algorithms 2 Journal de Mathématiques Pures et Appliquées. Neuvième Série 2 Journal of Dynamics and Differential Equations 2 NoDEA. Nonlinear Differential Equations and Applications 2 Differential Equations and Dynamical Systems 2 Communications in Nonlinear Science and Numerical Simulation 2 Communications on Pure and Applied Analysis 2 Mediterranean Journal of Mathematics 2 Networks and Heterogeneous Media 2 Set-Valued and Variational Analysis 2 Journal of Theoretical Biology 1 Nonlinearity 1 Physica A 1 ZAMP. Zeitschrift für angewandte Mathematik und Physik 1 Annali di Matematica Pura ed Applicata. Serie Quarta 1 Czechoslovak Mathematical Journal 1 Indiana University Mathematics Journal 1 Matematički Vesnik 1 Mathematics and Computers in Simulation 1 Results in Mathematics 1 SIAM Journal on Control and Optimization 1 Transactions of the American Mathematical Society 1 Systems & Control Letters 1 Zeitschrift für Analysis und ihre Anwendungen 1 Bulletin of the Korean Mathematical Society 1 Applied Mathematics and Mechanics. (English Edition) 1 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 1 Physica D 1 Applied Numerical Mathematics 1 Optimization 1 Mathematical and Computer Modelling 1 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 1 International Journal of Computer Mathematics 1 Indagationes Mathematicae. New Series 1 Electronic Journal of Differential Equations (EJDE) 1 Georgian Mathematical Journal 1 Journal of Mathematical Chemistry 1 Journal of Applied Analysis 1 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 1 Discrete Dynamics in Nature and Society 1 Communications in Contemporary Mathematics 1 International Journal of Nonlinear Sciences and Numerical Simulation 1 The ANZIAM Journal 1 Differential Equations 1 Nonlinear Analysis. Real World Applications 1 Journal of Applied Mathematics 1 Journal of Function Spaces and Applications 1 Mathematical Biosciences and Engineering 1 Complex Variables and Elliptic Equations 1 Discrete and Continuous Dynamical Systems. Series S 1 Kinetic and Related Models 1 Journal of Applied Analysis and Computation 1 Axioms 1 Evolution Equations and Control Theory 1 Mathematics 1 Chinese Journal of Mathematics 1 International Journal of Partial Differential Equations 1 Open Mathematics
all top 5
#### Cited in 17 Fields
134 Ordinary differential equations (34-XX) 58 Partial differential equations (35-XX) 53 Operator theory (47-XX) 17 Biology and other natural sciences (92-XX) 14 Numerical analysis (65-XX) 11 Systems theory; control (93-XX) 9 Calculus of variations and optimal control; optimization (49-XX) 8 Integral equations (45-XX) 7 Real functions (26-XX) 6 Operations research, mathematical programming (90-XX) 5 Difference and functional equations (39-XX) 4 Dynamical systems and ergodic theory (37-XX) 3 Global analysis, analysis on manifolds (58-XX) 3 Fluid mechanics (76-XX) 2 Statistical mechanics, structure of matter (82-XX) 1 General topology (54-XX) 1 Classical thermodynamics, heat transfer (80-XX)
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-05-14T16:53:53 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4076095521450043, "perplexity": 12967.644420861388}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991428.43/warc/CC-MAIN-20210514152803-20210514182803-00588.warc.gz"}
|
https://www.nist.gov/pml/time-and-frequency-division/popular-links/time-frequency-z
|
An official website of the United States government
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
# Time and Frequency from A to Z
## Share
A440
A440 (sometimes called A4) is the 440 Hz tone that serves as the internationally recognized standard for musical pitch. A440 is the musical note A above middle C. NIST has broadcast A440 from radio station WWV since 1936. The tones can currently be heard during minute 2 of each hour on WWV, and during minute 1 on WWVH.
Tuning a piano is an example of a simple frequency calibration that is done with the human ear. The piano tuner listens to a standard audio tone, compares it to the same note on the piano, and adjusts the piano until it agrees with the audio standard. The smallest frequency offset that a piano tuner can hear depends upon several factors, including the musical training of the listener. However, the just noticeable difference is often defined as 5 cents, where 1 cent is 1/100 of the ratio between two adjacent tones on the piano’s keyboard. Because there are 12 tones in a piano’s octave, the ratio for a frequency change of 1 cent is the 1200th root of 2. Therefore, raising a musical pitch by 1 cent requires multiplying by the 1200th root of 2, or 1.00057779. A 5 cent raise in pitch would require this to be done five times, and would equal 1.3 Hz when starting with a 440 Hz tone.
Accuracy
The degree of conformity of a measured or calculated value to its definition, related to the offset from an ideal value. In the time and frequency community, accuracy refers to the time offset or frequency offset of a device. For example, time offset is the difference between a measured on-time pulse and an ideal on-time pulse that coincides with UTC. Frequency offset is the difference between a measured frequency and a nominal frequency with zero uncertainty. The relationship between accuracy and stability is shown in the illustration.
The term uncertainty is usually preferred to accuracy when a quantitative measurement result is reported. Accuracy is often used in a qualitative sense. For example, we might say that an accurate time measurement was made with an uncertainty of 1 microsecond.
Active Frequency Standard
An atomic oscillator, usually a hydrogen maser, whose output signal is derived from the radiation emitted by the atom. Most commercially available atomic oscillators are passive frequency standards.
Aging
A change in frequency with time due to internal changes in an oscillator. Aging is usually a nearly linear change in the resonance frequency that can be either positive or negative, and occasionally, a reversal in direction of aging occurs. Aging occurs even when factors external to the oscillator, such as environment and power supply, are kept constant. Aging has many possible causes, including a buildup of foreign material on the crystal, changes in the oscillator circuitry, or changes in the quartz material or crystal structure. A high quality OCXO might age at a rate of < 5 × 10-9 per year, while a TCXO might age 100 times faster.
Allan Deviation
A non-classical statistic used to estimate stability. This statistic is sometimes called the Allan variance, but since it is the square root of the variance, its proper name is the Allan deviation. The nist-equation for the Allan deviation (with non-overlapping samples) is
$$\sigma_y(\tau)=\sqrt{\frac{1}{2(M-1)}{\sum} ^{M-1}_{i=1}(\overline{y}_{i+1}-\overline{y}_{i})^2}$$
where yi is a set of frequency offset measurements that consists of individual measurements, y1, y2, y3, and so on; M is the number of values in the yi series, and the data are equally spaced in segments τ seconds long. Or
$$\sigma_y(\tau)=\sqrt{\frac{1}{2(N-2)\tau^2}{\sum} ^{N-2}_{i=1}(x_{i+2}-2x_{i+1} + x_i)^2}$$
where xi is a series of phase measurements in time units that consists of individual measurements, x1, x2, x3, and so on, N is the number of values in the xi series, and the data are equally spaced in segments τ seconds long.
An Allan deviation graph is shown below. It shows the stability of the device improving as the averaging period gets longer, since some noise types can be removed by averaging. At some point, however, more averaging no longer improves the results. This point is called the noise floor, or the point where the remaining noise consists of nonstationary processes such as aging or random walk. The device in the graph has a noise floor of about 5 × 10-13 at τ = 1000 s.
The Allan deviation is also used to identify types of oscillator and measurement system noise. The slope of the Allan deviation line can identify the amount of averaging needed to remove these noise types, as shown in the graph below. Note that the Allan deviation does not distinguish between white phase noise and flicker phase noise.
Created May 12, 2010, Updated September 26, 2016
| 2021-05-09T11:10:51 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.608191192150116, "perplexity": 1108.6802037585164}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988966.82/warc/CC-MAIN-20210509092814-20210509122814-00474.warc.gz"}
|
https://mooseframework.inl.gov/source/bcs/PresetBC.html
|
# PresetBC
Similar to DirichletBC except the value is applied before the solve begins
## Description
The PresetBC takes the same inputs as DirichletBC and also acts as a Dirichlet boundary condition. However, the implementation is slightly different. PresetBC causes the value of the boundary condition to be applied before the solve begins where DirichletBC enforces the boundary condition as the solve progresses. In certain situations, one is better than another.
## Example Input Syntax
[BCs]
active = 'left right'
# We will use PresetBCs
[./left]
type = PresetBC
variable = u
boundary = 3
value = 0
[../]
[./right]
type = PresetBC
variable = u
boundary = 1
value = 1
[../]
[]
(test/tests/bcs/bc_preset_nodal/bc_preset_nodal.i)
## Input Parameters
• variableThe name of the variable that this boundary condition applies to
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this boundary condition applies to
• boundaryThe list of boundary IDs from the mesh where this boundary condition applies
C++ Type:std::vector
Options:
Description:The list of boundary IDs from the mesh where this boundary condition applies
• valueValue of the BC
C++ Type:double
Options:
Description:Value of the BC
### Required Parameters
• save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
• diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
### Optional Parameters
• control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
• enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
• seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Options:
Description:The seed for the master random number generator
• implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Options:
Description:Determines whether this object is calculated using an implicit or explicit form
• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Options:
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
• vector_tagsresidualThe tag for the vectors this Kernel should fill
Default:residual
C++ Type:MultiMooseEnum
Options:nontime time residual
Description:The tag for the vectors this Kernel should fill
• extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector
Options:
Description:The extra tags for the vectors this Kernel should fill
• matrix_tagssystem timeThe tag for the matrices this Kernel should fill
Default:system time
C++ Type:MultiMooseEnum
Options:nontime system time
Description:The tag for the matrices this Kernel should fill
• extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector
Options:
Description:The extra tags for the matrices this Kernel should fill
| 2018-12-14T03:34:29 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.17127805948257446, "perplexity": 5964.994008800848}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376825349.51/warc/CC-MAIN-20181214022947-20181214044447-00367.warc.gz"}
|
https://par.nsf.gov/biblio/10347680-high-resolution-carma-observation-molecular-gas-north-america-pelican-nebulae
|
High-resolution CARMA Observation of Molecular Gas in the North America and Pelican Nebulae
Abstract In this paper, we present the first results from a CARMA high-resolution 12 CO(1-0), 13 CO(1-0), and C 18 O(1-0) molecular line survey of the North America and Pelican (NAP) Nebulae. CARMA observations have been combined with single-dish data from the Purple Mountain 13.7 m telescope, to add short spacings and to produce high-dynamic-range images. We find that the molecular gas is predominantly shaped by the W80 H ii bubble, driven by an O star. Several bright rims noted in the observation are probably remnant molecular clouds, heated and stripped by the massive star. Matching these rims in molecular lines and optical images, we construct a model of the three-dimensional structure of the NAP complex. Two groups of molecular clumps/filaments are on the near side of the bubble: one is being pushed toward us, whereas the other is moving toward the bubble. Another group is on the far side of the bubble, and moving away. The young stellar objects in the Gulf region reside in three different clusters, each hosted by a cloud from one of the three molecular clump groups. Although all gas content in the NAP is impacted by feedback from the central O star, some regions more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10347680
Journal Name:
The Astronomical Journal
Volume:
161
Issue:
5
Page Range or eLocation-ID:
229
ISSN:
0004-6256
3. Abstract We introduce new analysis methods for studying the star cluster formation processes in Orion A, especially examining the scenario of a cloud–cloud collision. We utilize the CARMA–NRO Orion survey 13CO (1–0) data to compare molecular gas to the properties of young stellar objects from the SDSS III IN-SYNC survey. We show that the increase of $v_{\rm {}^{13}CO} - v_{\rm YSO}$ and Σ scatter of older YSOs can be signals of cloud–cloud collision. SOFIA-upGREAT 158 μm [C ii] archival data toward the northern part of Orion A are also compared to the 13CO data to test whether the position and velocity offsets between the emission from these two transitions resemble those predicted by a cloud–cloud collision model. We find that the northern part of Orion A, including regions ONC-OMC-1, OMC-2, OMC-3, and OMC-4, shows qualitative agreements with the cloud–cloud collision scenario, while in one of the southern regions, NGC 1999, there is no indication of such a process in causing the birth of new stars. On the other hand, another southern cluster, L 1641 N, shows slight tendencies of cloud–cloud collision. Overall, our results support the cloud–cloud collision process as being an important mechanism for star cluster formation in Orion A.
| 2023-03-31T07:34:53 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.46232420206069946, "perplexity": 2550.54018047384}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949573.84/warc/CC-MAIN-20230331051439-20230331081439-00538.warc.gz"}
|
https://mfix.netl.doe.gov/doc/mfix/20.1.0/reference/discrete_element.html
|
# 8.3.6. Discrete Element¶
## 8.3.6.1. Discrete Element - Common¶
These are keywords common to Discrete Element Model (DEM) and Particles In Cell (PIC).
### 8.3.6.1.1. PARTICLES¶
Data Type: INTEGER
Applies to Solids Model(s): DEM
Number of particles to be read in from the particle_input.dat file. This value is overwritten when using automatic particle generation. A simulation with a mass inflow BC can start without solids by setting PARTICLES = 0.
### 8.3.6.1.2. GENER_PART_CONFIG¶
Data Type: LOGICAL
Applies to Solids Model(s): DEM
Automatically generate the initial particle position and velocity data based on the parameters specified for each initial condition (IC) region.
Table 8.43 Valid Values
Name
Default?
Description
.TRUE.
Generate particle configuration based on the initial condition parameters. Data provided in the particle_input.dat file, if present, is ignored.
.FALSE.
Particle position and velocity data are provided in the particle_input.dat file. A runtime error occurs if this file is not provided.
### 8.3.6.1.3. DES_ONEWAY_COUPLED¶
Data Type: LOGICAL
Applies to Solids Model(s): DEM
Run one-way coupled simulations [default .FALSE.].
If set, the fluid does not see the particles in terms of drag force. The effect of particle volume is still felt by the fluid through non-unity voidage values.
Table 8.44 Valid Values
Name
Default?
Description
.FALSE.
Two-way particle-fluid coupling.
.TRUE.
One-way particle-fluid coupling (fluid does not see particle drag).
### 8.3.6.1.4. DES_INTG_METHOD¶
Data Type: CHARACTER
Applies to Solids Model(s): DEM
Time stepping scheme.
Table 8.45 Valid Values
Name
Default?
Description
EULER
First-order Euler scheme.
ADAMS_BASHFORTH
### 8.3.6.1.5. DESGRIDSEARCH_IMAX¶
Data Type: INTEGER
Applies to Solids Model(s): DEM
Number of des grid cells in the I-direction. If left undefined, then it is set by MFiX such that its size equals three times the maximum particle diameter with a minimum of 1 cell.
### 8.3.6.1.6. DESGRIDSEARCH_JMAX¶
Data Type: INTEGER
Applies to Solids Model(s): DEM
Number of des grid cells in the J-direction. If left undefined, then it is set by MFiX such that its size equals three times the maximum particle diameter with a minimum of 1 cell.
### 8.3.6.1.7. DESGRIDSEARCH_KMAX¶
Data Type: INTEGER
Applies to Solids Model(s): DEM
Number of des grid cells in the K-direction. If left undefined, then it is set by MFiX such that its size equals three times the maximum particle diameter with a minimum of 1 cell.
### 8.3.6.1.8. DES_INTERP_SCHEME¶
Data Type: CHARACTER
Applies to Solids Model(s): DEM
Specify the scheme used to map data to/from a particle’s position and the Eulerian grid. This keyword is required when DES_INTERP_MEAN_FIELDS and/or DES_INTERP_ON are specified.
Table 8.46 Valid Values
Name
Default?
Description
NONE
Do not use interpolation.
GARG_2012
Interpolate to/from a particle’s position using the corners (nodes) of the fluid cells. This was the default behavior prior to the 2015-1 Release. See Garg et al. (2012) Documentation of the open-source MFiX-DEM software for gas-solids flows.
SQUARE_DPVM
Divided Particle Volume Method: Information is interpolated to/from a particles position using a square filter of size DES_INTERP_WIDTH.
LINEAR_HAT
Linear interpolation: Hat functions are used to distribute particle information.
### 8.3.6.1.9. DES_INTERP_WIDTH¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Length used in interpolating data to/from a particle’s position and the Eulerian grid. The interpolation width is only applicable to the DPVM_SQUARE and DPVM_GAUSS interpolation schemes as the GARG_2012 scheme’s interpolation width is determined by the Eulerian grid dimensions.
• The interpolation half-width cannot exceed the minimum cell dimension because interpolation is restricted to the 27-cell neighborhood surrounding a particle (9-cell neighborhood in 2D).
• It is recommended that the DES_INTERP_WIDTH be set equal to the maximum particle diameter when using STL defined boundaries. Field data can be smoothed by specifying DES_DIFFUSE_WIDTH.
### 8.3.6.1.10. DES_INTERP_ON¶
Data Type: LOGICAL
Applies to Solids Model(s): DEM
Enable/disable interpolation of field quantities to a particle’s position. This is used in calculating gas-particle interactions, such as the drag force.
Table 8.47 Valid Values
Name
Default?
Description
.FALSE.
Use fluid values from the cell containing the particle’s center.
.TRUE.
Interpolate fluid values from the 27-cell neighborhood to a particle’s position.
### 8.3.6.1.11. DES_INTERP_MEAN_FIELDS¶
Data Type: LOGICAL
Applies to Solids Model(s): DEM
Enable/disable interpolation of particle data (e.g., solids volume and drag force) from a particle’s position to the Eulerian grid.
Table 8.48 Valid Values
Name
Default?
Description
.FALSE.
Assign particle data to the fluid grid cell containing the particle’s center.
.TRUE.
Interpolate particle data from the particle’s position to the 27-cell neighborhood surrounding the particle.
### 8.3.6.1.12. DES_DIFFUSE_WIDTH¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
The length scale used to smooth dispersed phase averaged fields by solving a diffusion equation. This approach is typically used when particle sizes near or exceed the size of the Eulerian grid cell sizes.
• Mean field diffusion is disabled if DES_DIFFUSE_WIDTH is not specified.
• Mean field diffusion cannot be used with the GARG_2012 interpolation scheme.
• It is recommended that mean field diffusion be used in conjunction with DES_EXPLICITLY_COUPLED to minimize the computational cost of diffusing field data.
• The DES diffusion equation is listed as equation type 10 in the Numerical Parameters section.
### 8.3.6.1.13. DES_EXPLICITLY_COUPLED¶
Data Type: LOGICAL
Applies to Solids Model(s): DEM
Enable/Disable explicit coupling of DEM solids and the fluid. This algorithm is presently limited to hydrodynamic simulations.
Table 8.49 Valid Values
Name
Default?
Description
.FALSE.
The fluid and particles calculate interphase forces at their respective time scales. The fluid phase calculates the interphase coupling forces once per fluid time step. Similarly, DEM particles calculate the interface coupling forces at each solids time-step. The DEM must also bin particles to the fluid grid and recalculate the fluid volume fraction every time-step.
.TRUE.
Interphase forces are calculated during the fluid time step and stored for each particle. The interphase forces are then distributed among the solids time-steps. This approach can substantially reduce the computational overhead for coupled simulations.
## 8.3.6.2. Discrete Element Model¶
These keywords relate to the Discrete Element Model (DEM).
### 8.3.6.2.1. NFACTOR¶
Data Type: INTEGER
The number of iterations of a pure granular simulation to let the initial particle configuration settle before a coupled gas-solid calculation is started.
### 8.3.6.2.2. NEIGHBOR_SEARCH_N¶
Data Type: INTEGER
Maximum number of steps through a DEM loop before a neighbor search will be performed. The search may be called earlier based on other logic.
Data Type: DOUBLE PRECISION
Ratio of the distance (imaginary sphere radius) to particle radius that is allowed before a neighbor search is performed. This works in conjunction with the logic imposed by NEIGHBOR_SEARCH_N in deciding calls to the neighbor search algorithm.
### 8.3.6.2.5. FACTOR_RLM¶
Data Type: DOUBLE PRECISION
Effectively increases the radius of a particle (multiple of the sum of particle radii) during the building of particle neighbor list.
### 8.3.6.2.6. USE_VDH_DEM_MODEL¶
Data Type: LOGICAL
Flag to use van der Hoef et al. (2006) model for adjusting the rotation of the contact plane. See the MFiX-DEM documentation.
### 8.3.6.2.7. DES_COLL_MODEL¶
Data Type: CHARACTER
Collision model for the soft-sphere approach used in DEM model. All models require specifying the following parameters: DES_EN_INPUT, DES_EN_WALL_INPUT, MEW, and MEW_W.
Table 8.51 Valid Values
Name
Default?
Description
LSD
The linear spring-dashpot model. Requires: KN, KN_W, KT_FAC, KT_W_FAC, DES_ETAT_FAC, DES_ETAT_W_FAC.
HERTZIAN
The Hertzian model. Requires: DES_ET_INPUT, DES_ET_WALL_INPUT, E_YOUNG, EW_YOUNG V_POISSON, VW_POISSON.
### 8.3.6.2.8. KN¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Normal spring constant [N/m in SI] for inter-particle collisions. Required when using the linear spring-dashpot collision model.
### 8.3.6.2.9. KT_FAC¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Ratio of the tangential spring constant to normal spring constant for inter-particle collisions. Use it to specify the tangential spring constant for particle-particle collisions as KT_FAC*KN. Required when using the linear spring-dashpot collision model.
### 8.3.6.2.10. KN_W¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Normal spring constant [N/m in SI] for particle-wall collisions. Required when using the linear spring-dashpot collision model.
### 8.3.6.2.11. KT_W_FAC¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Ratio of the tangential spring constant to normal spring constant for particle-wall collisions. Use it to specify the tangential spring constant for particle-wall collisions as KT_W_FAC*KN_W. Required when using the linear spring-dashpot collision model.
### 8.3.6.2.12. MEW¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Inter-particle Coulomb friction coefficient.
### 8.3.6.2.13. MEW_W¶
Data Type: DOUBLE PRECISION
Particle-wall Coulomb friction coefficient.
### 8.3.6.2.14. DES_EN_INPUT(INDEX)¶
Data Type: DOUBLE PRECISION
• $$1 \le Index \le MMAX*(MMAX-1)/2$$
Applies to Solids Model(s): DEM
Normal restitution coefficient for inter-particle collisions used to determine the inter-particle normal damping factor.
Values should be defined for a single dimensional array. For example, a simulation with three solids phases (MMAX=3) needs six values: en11, en12, en13; en22 en 23; en33.
### 8.3.6.2.15. DES_EN_WALL_INPUT(INDEX)¶
Data Type: DOUBLE PRECISION
• $$1 \le Index \le MMAX$$
Applies to Solids Model(s): DEM
Normal restitution coefficient for particle-wall collisions used to determine the particle-wall normal damping factor.
Values should be defined in a single dimensional array. For example, a simulation with three solids phases (MMAX=3) needs three values: enw1, enw2, enw3.
### 8.3.6.2.16. DES_ET_INPUT(INDEX)¶
Data Type: DOUBLE PRECISION
• $$1 \le Index \le MMAX*(MMAX-1)/2$$
Applies to Solids Model(s): DEM
Tangential restitution coefficient for inter-particle collisions. Values are defined in a one dimensional array. This is required input when using the Hertzian collision model.
### 8.3.6.2.17. DES_ET_WALL_INPUT(INDEX)¶
Data Type: DOUBLE PRECISION
• $$1 \le Index \le MMAX$$
Applies to Solids Model(s): DEM
Tangential restitution coefficient for particle wall collisions. Values are defined in a one dimensional array. This is required input when using the Hertzian collision model.
### 8.3.6.2.18. DES_ETAT_FAC¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): DEM
Ratio of the tangential damping factor to the normal damping factor for inter-particle collisions. Required for the linear spring-dashpot collision model.
Table 8.52 Valid Values
Name
Default?
Description
UNDEFINED
For LSD model, if left undefined, MFiX reverts to default value of 0.5.
### 8.3.6.2.19. DES_ETAT_W_FAC¶
Data Type: DOUBLE PRECISION
Ratio of the tangential damping factor to the normal damping factor for particle-wall collisions. Required for the linear spring-dashpot model for soft-spring collision modelling under DEM. For the Hertzian model, the tangential damping coefficients have to be explicitly specified and specification of this variable is not required.
Table 8.53 Valid Values
Name
Default?
Description
UNDEFINED
For LSD model, if left undefined, MFiX will revert to default value of 0.5
### 8.3.6.2.20. EW_YOUNG¶
Data Type: DOUBLE PRECISION
Young’s modulus for the wall [Pa in SI]. Required when using the Hertzian collision model.
### 8.3.6.2.21. VW_POISSON¶
Data Type: DOUBLE PRECISION
Poisson ratio for the wall. Required when using the Hertzian collision model.
### 8.3.6.2.22. E_YOUNG(PHASE)¶
Data Type: DOUBLE PRECISION
• $$1 \le Phase \le DES{\_}MMAX$$
Young’s modulus for the particle [Pa in SI]. Required when using the Hertzian collision model.
### 8.3.6.2.23. V_POISSON(PHASE)¶
Data Type: DOUBLE PRECISION
• $$1 \le Phase \le DES{\_}MMAX$$
Poisson’s ratio for the particle. Required when using the Hertzian collision model.
### 8.3.6.2.24. USE_COHESION¶
Data Type: LOGICAL
Flag to enable/disable cohesion model.
### 8.3.6.2.25. VAN_DER_WAALS¶
Data Type: LOGICAL
Flag to turn on the Hamaker van der Waals forces.
### 8.3.6.2.26. HAMAKER_CONSTANT¶
Data Type: DOUBLE PRECISION
Hamaker constant used in particle-particle cohesive interactions.
### 8.3.6.2.27. WALL_HAMAKER_CONSTANT¶
Data Type: DOUBLE PRECISION
Hamaker constant used in particle-wall cohesive interactions.
### 8.3.6.2.28. VDW_OUTER_CUTOFF¶
Data Type: DOUBLE PRECISION
Maximum separation distance above which van der Waals forces are not implemented.
### 8.3.6.2.29. VDW_INNER_CUTOFF¶
Data Type: DOUBLE PRECISION
Minimum separation distance below which van der Waals forces are calculated using a surface adhesion model.
### 8.3.6.2.30. WALL_VDW_OUTER_CUTOFF¶
Data Type: DOUBLE PRECISION
Maximum separation distance above which van der Waals forces are not implemented (particle-wall interactions).
### 8.3.6.2.31. WALL_VDW_INNER_CUTOFF¶
Data Type: DOUBLE PRECISION
Minimum separation distance below which van der Waals forces are calculated using a surface adhesion model (particle-wall interactions).
### 8.3.6.2.32. ASPERITIES¶
Data Type: DOUBLE PRECISION
Mean radius of surface asperities that influence the cohesive force. See H. Rumpf, Particle Technology, Chapman & Hall, London/New York, 1990.
### 8.3.6.2.33. DES_CONV_CORR¶
Data Type: CHARACTER
Specify the Nusselt number correlation used for particle-gas convection.
Table 8.54 Valid Values
Name
Default?
Description
RANZ_1952
Ranz, W.E. and Marshall, W.R. (1952). Chemical Engineering Progress, 48: 141-146 and 173-180
### 8.3.6.2.34. DES_MIN_COND_DIST¶
Data Type: DOUBLE PRECISION
Minimum separation distance between the surfaces of two contacting particles.
### 8.3.6.2.35. FLPC¶
Data Type: DOUBLE PRECISION
Fluid lens proportionality constant used to calculate the radius of the fluid lens that surrounds a particle. This parameter is used in the particle-fluid-particle conduction model.
### 8.3.6.2.36. DES_EM(PHASE)¶
Data Type: DOUBLE PRECISION
• $$1 \le Phase \le DES{\_}MMAX$$
Emissivity of solids phase.
### 8.3.6.2.37. E_YOUNG_ACTUAL(PHASE)¶
Data Type: DOUBLE PRECISION
• $$1 \le Phase \le DES{\_}MMAX$$
Actual Young’s modulus for the particle [Pa in SI]. Used for computing correction terms for DEM conduction.
### 8.3.6.2.38. EW_YOUNG_ACTUAL¶
Data Type: DOUBLE PRECISION
Actual Young’s modulus for the walls [Pa in SI]. Used for computing correction terms for DEM conduction.
### 8.3.6.2.39. V_POISSON_ACTUAL(PHASE)¶
Data Type: DOUBLE PRECISION
• $$1 \le Phase \le DES{\_}MMAX$$
Poisson’s ratio for the particle. Used for computing correction terms for DEM conduction.
### 8.3.6.2.40. VW_POISSON_ACTUAL¶
Data Type: DOUBLE PRECISION
Poisson’s ratio for the wall. Used for computing correction terms for DEM conduction.
### 8.3.6.2.41. MINIMIZE_DES_FACET_LIST¶
Data Type: LOGICAL
Flag to turn on/off optimizing the list of facets at each des grid cell.
### 8.3.6.2.42. DLB_DT¶
Data Type: DOUBLE PRECISION
Time interval at which Dynamic Load Balance (DLB) is performed (sec)
Table 8.55 Valid Values
Name
Default?
Description
UNDEFINED
: UNDEFINED value turns Dynamic Load Balance off
>0
: Any positive value turns Dynamic Load Balance on
### 8.3.6.2.43. DLB_EGW¶
Data Type: DOUBLE PRECISION
Eulerian Grid Weight use in Dynamic Load Balance. A value of zero means the balancing only considers particles. A very large value means the partition will balance only the fluid mesh. Finding the optimal value will require trial and error.
Table 8.56 Valid Values
Name
Default?
Description
>=0
## 8.3.6.3. Particles in Cell¶
These keywords relate to the Particle in Cell model. Please note that the PIC model is currently not supported by the GUI, because PIC support is undergoing a rewrite in the solver.
### 8.3.6.3.1. FRIC_EXP_PIC¶
Data Type: DOUBLE PRECISION
Volume fraction exponential scale factor in frictional stress model.
### 8.3.6.3.2. PSFAC_FRIC_PIC¶
Data Type: DOUBLE PRECISION
Pressure linear scale factor in frictional stress model.
### 8.3.6.3.3. MPPIC_COEFF_EN1¶
Data Type: DOUBLE PRECISION
An empirical dampening factor for the frictional stress model.
### 8.3.6.3.4. FRIC_NON_SING_FAC¶
Data Type: DOUBLE PRECISION
Non-singularity term in frictional stress model.
### 8.3.6.3.5. MPPIC_COEFF_EN_WALL¶
Data Type: DOUBLE PRECISION
Normal coefficient of restitution for parcel-wall collisions.
### 8.3.6.3.6. MPPIC_COEFF_ET_WALL¶
Data Type: DOUBLE PRECISION
Tangential coefficient of restitution for parcel-wall collisions.
### 8.3.6.3.7. MPPIC_VELFAC_COEFF¶
Data Type: DOUBLE PRECISION
Solids slip velocity scale factor. This term can be used to scale the bulk solids velocity when calculating parcel/bulk solids slip velocity. Scaling is uniform in all three directions.
| 2021-11-30T22:01:15 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7215641736984253, "perplexity": 13308.412644410493}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964359073.63/warc/CC-MAIN-20211130201935-20211130231935-00325.warc.gz"}
|
https://www.zbmath.org/authors/?q=ai%3Achen.xiaojun
|
# zbMATH — the first resource for mathematics
## Chen, Xiaojun
Compute Distance To:
Author ID: chen.xiaojun Published as: Chen, X.; Chen, X. J.; Chen, Xiao Jun; Chen, Xiaojun External Links: MGP · Wikidata
Documents Indexed: 45 Publications since 1999 Reviewing Activity: 18 Reviews
all top 5
#### Co-Authors
2 single-authored 5 Eshmatov, Farkhod 2 Gan, Wee Liang 2 Her, Hailong 2 Sun, Shanzhong 2 Yang, Song 1 Berest, Yuri Yu. 1 Eshmatov, Alimjon 1 Liu, Leilei 1 Ramadoss, Ajay C. 1 Yang, Xiangdong 1 Zhou, Guodong
all top 5
#### Serials
2 Journal of Geometry and Physics 1 Communications in Mathematical Physics 1 Advances in Mathematics 1 Journal of Pure and Applied Algebra 1 Pacific Journal of Mathematics 1 Transactions of the American Mathematical Society 1 Advances in Mathematics 1 Frontiers of Mathematics in China 1 Journal of Noncommutative Geometry
all top 5
#### Fields
6 Differential geometry (53-XX) 5 Associative rings and algebras (16-XX) 4 Algebraic topology (55-XX) 3 Algebraic geometry (14-XX) 3 Nonassociative rings and algebras (17-XX) 2 Category theory; homological algebra (18-XX) 1 $$K$$-theory (19-XX) 1 Functional analysis (46-XX) 1 Global analysis, analysis on manifolds (58-XX)
#### Citations contained in zbMATH
21 Publications have been cited 135 times in 126 Documents Cited by Year
Herringbone buckling patterns of compressed thin films on compliant substrates. Zbl 1111.74362
Chen, X.; Hutchinson, John W.
2004
Non-Lipschitz $$\ell_p$$-regularization and box constrained model for image restoration. Zbl 1373.94080
Chen, Xiaojun; Ng, Michael K.; Zhang, Chao
2012
A modified SSOR preconditioner for sparse symmetric indefinite linear systems of equations. Zbl 1114.74056
Chen, X.; Toh, K. C.; Phoon, K. K.
2006
Noncommutative Poisson structures, derived representation schemes and Calabi-Yau algebras. Zbl 1316.17015
Berest, Yuri; Chen, Xiaojun; Eshmatov, Farkhod; Ramadoss, Ajay
2012
Batalin-Vilkovisky algebras and the noncommutative Poincaré duality of Koszul Calabi-Yau algebras. Zbl 1401.14018
Chen, Xiaojun; Yang, Song; Zhou, Guodong
2016
Computational formula of depth for Catmull-Clark subdivision surfaces. Zbl 1097.65029
Zeng, Xiao-Ming; Chen, X. J.
2006
Invariants of the velocity-gradient tensor in a spatially developing inhomogeneous turbulent flow. Zbl 1383.76179
Buxton, O. R. H.; Breda, M.; Chen, X.
2017
The derived non-commutative Poisson bracket on Koszul Calabi-Yau algebras. Zbl 06718164
Chen, Xiaojun; Eshmatov, Alimjon; Eshmatov, Farkhod; Yang, Song
2017
Quantization of the Lie bialgebra of string topology. Zbl 1262.17010
Chen, Xiaojun; Eshmatov, Farkhod; Gan, Wee Liang
2011
Complexity of partially separable convexly constrained optimization with non-Lipschitzian singularities. Zbl 1411.90318
Chen, Xiaojun; Toint, Ph. L.; Wang, H.
2019
Structural reliability analysis with imprecise random and interval fields. Zbl 07166627
Gao, Wei; Wu, Di; Gao, Kang; Chen, Xiaojun; Tin-Loi, Francis
2018
Sparse envelope model: efficient estimation and response variable selection in multivariate linear regression. Zbl 07072139
Su, Z.; Zhu, G.; Chen, X.; Yang, Y.
2016
Partitioned versus global Krylov subspace iterative methods for FE solution of 3-D Biot’s problem. Zbl 1173.74405
Chen, X.; Phoon, K. K.; Toh, K. C.
2007
Snap-through buckling of initially curved microbeam subject to an electrostatic force. Zbl 1371.74106
Chen, X.; Meguid, S. A.
2015
Multistage scenario-based interval-stochastic programming for planning water resources allocation. Zbl 1418.90183
Li, Y. P.; Huang, G. H.; Chen, X.
2009
A novel DCT-based algorithm for computing the modulated complex lapped transform. Zbl 1374.94695
Chen, X.; Dai, Q.
2006
Reasoning about nondeterministic and concurrent actions: A process algebra approach. Zbl 0910.68075
Chen, Xiao Jun; de Giacomo, Giuseppe
1999
Structure evolution at early stage of boundary-layer transition: simulation and experiment. Zbl 07193492
Jiang, X. Y.; Lee, C. B.; Chen, X.; Smith, C. R.; Linden, P. F.
2020
Regularized two-stage stochastic variational inequalities for Cournot-Nash equilibrium under uncertainty. Zbl 07266714
Jiang, Jie; Shi, Yun; Wang, Xiaozhou; Chen, Xiaojun
2019
A parallel iterative algorithm for differential linear complementarity problems. Zbl 1379.65050
Wu, Shu-Lin; Chen, Xiaojun
2017
A double Poisson algebra structure on Fukaya categories. Zbl 1353.53087
Chen, Xiaojun; Her, Hai-Long; Sun, Shanzhong; Yang, Xiangdong
2015
Structure evolution at early stage of boundary-layer transition: simulation and experiment. Zbl 07193492
Jiang, X. Y.; Lee, C. B.; Chen, X.; Smith, C. R.; Linden, P. F.
2020
Complexity of partially separable convexly constrained optimization with non-Lipschitzian singularities. Zbl 1411.90318
Chen, Xiaojun; Toint, Ph. L.; Wang, H.
2019
Regularized two-stage stochastic variational inequalities for Cournot-Nash equilibrium under uncertainty. Zbl 07266714
Jiang, Jie; Shi, Yun; Wang, Xiaozhou; Chen, Xiaojun
2019
Structural reliability analysis with imprecise random and interval fields. Zbl 07166627
Gao, Wei; Wu, Di; Gao, Kang; Chen, Xiaojun; Tin-Loi, Francis
2018
Invariants of the velocity-gradient tensor in a spatially developing inhomogeneous turbulent flow. Zbl 1383.76179
Buxton, O. R. H.; Breda, M.; Chen, X.
2017
The derived non-commutative Poisson bracket on Koszul Calabi-Yau algebras. Zbl 06718164
Chen, Xiaojun; Eshmatov, Alimjon; Eshmatov, Farkhod; Yang, Song
2017
A parallel iterative algorithm for differential linear complementarity problems. Zbl 1379.65050
Wu, Shu-Lin; Chen, Xiaojun
2017
Batalin-Vilkovisky algebras and the noncommutative Poincaré duality of Koszul Calabi-Yau algebras. Zbl 1401.14018
Chen, Xiaojun; Yang, Song; Zhou, Guodong
2016
Sparse envelope model: efficient estimation and response variable selection in multivariate linear regression. Zbl 07072139
Su, Z.; Zhu, G.; Chen, X.; Yang, Y.
2016
Snap-through buckling of initially curved microbeam subject to an electrostatic force. Zbl 1371.74106
Chen, X.; Meguid, S. A.
2015
A double Poisson algebra structure on Fukaya categories. Zbl 1353.53087
Chen, Xiaojun; Her, Hai-Long; Sun, Shanzhong; Yang, Xiangdong
2015
Non-Lipschitz $$\ell_p$$-regularization and box constrained model for image restoration. Zbl 1373.94080
Chen, Xiaojun; Ng, Michael K.; Zhang, Chao
2012
Noncommutative Poisson structures, derived representation schemes and Calabi-Yau algebras. Zbl 1316.17015
Berest, Yuri; Chen, Xiaojun; Eshmatov, Farkhod; Ramadoss, Ajay
2012
Quantization of the Lie bialgebra of string topology. Zbl 1262.17010
Chen, Xiaojun; Eshmatov, Farkhod; Gan, Wee Liang
2011
Multistage scenario-based interval-stochastic programming for planning water resources allocation. Zbl 1418.90183
Li, Y. P.; Huang, G. H.; Chen, X.
2009
Partitioned versus global Krylov subspace iterative methods for FE solution of 3-D Biot’s problem. Zbl 1173.74405
Chen, X.; Phoon, K. K.; Toh, K. C.
2007
A modified SSOR preconditioner for sparse symmetric indefinite linear systems of equations. Zbl 1114.74056
Chen, X.; Toh, K. C.; Phoon, K. K.
2006
Computational formula of depth for Catmull-Clark subdivision surfaces. Zbl 1097.65029
Zeng, Xiao-Ming; Chen, X. J.
2006
A novel DCT-based algorithm for computing the modulated complex lapped transform. Zbl 1374.94695
Chen, X.; Dai, Q.
2006
Herringbone buckling patterns of compressed thin films on compliant substrates. Zbl 1111.74362
Chen, X.; Hutchinson, John W.
2004
Reasoning about nondeterministic and concurrent actions: A process algebra approach. Zbl 0910.68075
Chen, Xiao Jun; de Giacomo, Giuseppe
1999
all top 5
#### Cited by 270 Authors
8 Wu, Chunlin 7 Ferronato, Massimiliano 5 Chen, Xiaojun 5 Gambolati, Giuseppe 5 Huang, Yonggang Young 5 Potier-Ferry, Michel 5 Rogers, John A. 5 Zeng, Chao 4 Hu, Heng 4 Jiang, Hanqing 3 Audoly, Basile 3 Bergamaschi, Luca 3 Bian, Wei 3 Boudaoud, Arezki 3 Chen, Xiaojun 3 Eshmatov, Farkhod 3 Feng, Xiqiao 3 Mustafa, Ghulam 2 Berest, Yuri Yu. 2 Britaňák, Vladimír 2 Damil, Noureddine 2 Hashmi, Sadiq 2 Her, Hailong 2 Huang, Yakui 2 Hutchinson, John Woodside 2 Jia, Rui 2 Khang, Dahl-Young 2 Kong, Lingchen 2 Leray, Johan 2 Li, Bo 2 Liu, Hongwei 2 Liu, Wanquan 2 Ou, Zhicheng 2 Phoon, Kok-Kwang 2 Ramadoss, Ajay C. 2 Su, Zhihua 2 Sun, Shanzhong 2 Sun, Yugang 2 Suo, Zhiyong 2 Triantafyllidis, Nicolas 2 Wang, Weina 2 Xiu, Xianchao 2 Yao, Xiaohu 2 Zhang, Shuzhong 2 Zhang, Xiaoqing 1 An, Baiguo 1 Andersons, J. 1 Ansari, Reza 1 Arriëns, Huibert J. Lincklaen 1 Bai, Zhongzhi 1 Bakiler, A. Derya 1 Barber, Joel R. 1 Béda, Péter B. 1 Belouettar, Salim 1 Boccuto, Antonio 1 Breda, Marco 1 Breid, D. 1 Bremner, Murray R. 1 Buxton, Oliver R. H. 1 Caccetta, Louis 1 Cai, Shilian 1 Calandra, Henri 1 Cao, Yanping 1 Carter, Douglas W. 1 Castelletto, Nicola 1 Chemla, Sophie 1 Chen, Guoliang 1 Chen, Jiwei 1 Chen, Tuo 1 Chen, Weiqiu 1 Chen, Xi 1 Chen, Xi 1 Chen, Xueyuan 1 Chen, Yichao 1 Cheng, Guanghui 1 Cheng, Lizhi 1 Chudnovsky, Alexander 1 Clipici, Dragos 1 Coletti, Filippo 1 Cong, Weijie 1 Conti, Sergio 1 Crosby, A. J. 1 Dai, Hui-Hui 1 Dai, Yu-Hong 1 Danas, Kostas 1 de Boer, Frank S. 1 De Giacomo, Giuseppe 1 de Vries, Wieke 1 Deng, Chongyang 1 Ding, Shanshan 1 Dzenis, Yuris A. 1 Ebrahimi, Farzad 1 Eshmatov, Alimjon 1 Fan, Xuejun 1 Fang, Dina 1 Fei, Huiyang 1 Feng, Xue 1 Frigo, Matteo 1 Gao, Wei 1 Gao, Yiming ...and 170 more Authors
all top 5
#### Cited in 69 Serials
13 Journal of the Mechanics and Physics of Solids 6 Computer Methods in Applied Mechanics and Engineering 5 International Journal of Solids and Structures 5 Journal of Fluid Mechanics 4 Journal of Computational Physics 4 SIAM Journal on Optimization 4 European Journal of Mechanics. A. Solids 3 Journal of Geometry and Physics 3 Computational Optimization and Applications 3 Journal of Noncommutative Geometry 2 International Journal of Engineering Science 2 International Journal for Numerical and Analytical Methods in Geomechanics 2 Inverse Problems 2 Advances in Mathematics 2 International Journal for Numerical Methods in Engineering 2 Journal of Computational and Applied Mathematics 2 Journal of Scientific Computing 2 Signal Processing 2 Journal of Global Optimization 2 Applied Mathematical Modelling 2 Mathematical Programming. Series A. Series B 2 Journal of Mathematical Imaging and Vision 2 Theory and Applications of Categories 2 Journal of Applied Mathematics 2 Frontiers of Mathematics in China 2 SIAM Journal on Imaging Sciences 1 Artificial Intelligence 1 Archive for Rational Mechanics and Analysis 1 Journal of Mathematical Analysis and Applications 1 The Annals of Statistics 1 Applied Mathematics and Computation 1 Information Sciences 1 Journal of Approximation Theory 1 Journal of Optimization Theory and Applications 1 Meccanica 1 Memoirs of the American Mathematical Society 1 SIAM Journal on Numerical Analysis 1 Statistics & Probability Letters 1 Optimization 1 Numerical Methods for Partial Differential Equations 1 Numerical Algorithms 1 European Journal of Operational Research 1 International Journal of Computer Mathematics 1 Computational Statistics and Data Analysis 1 Applicable Algebra in Engineering, Communication and Computing 1 Archive of Applied Mechanics 1 Journal of Nonlinear Science 1 SIAM Journal on Scientific Computing 1 Numerical Linear Algebra with Applications 1 Selecta Mathematica. New Series 1 Advances in Computational Mathematics 1 Mathematical Problems in Engineering 1 Mathematics and Mechanics of Solids 1 Abstract and Applied Analysis 1 Philosophical Transactions of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 1 Computational Geosciences 1 Stochastic Environmental Research and Risk Assessment 1 International Journal of Nonlinear Sciences and Numerical Simulation 1 Algebraic & Geometric Topology 1 Acta Mechanica Sinica 1 Optimization Letters 1 Inverse Problems and Imaging 1 Electronic Journal of Statistics 1 Science China. Mathematics 1 Numerical Algebra, Control and Optimization 1 ISRN Applied Mathematics 1 Journal de l’École Polytechnique – Mathématiques 1 AMM. Applied Mathematics and Mechanics. (English Edition) 1 Proceedings of the Royal Society of London. A. Mathematical, Physical and Engineering Sciences
all top 5
#### Cited in 30 Fields
46 Mechanics of deformable solids (74-XX) 37 Numerical analysis (65-XX) 29 Operations research, mathematical programming (90-XX) 13 Information and communication theory, circuits (94-XX) 10 Associative rings and algebras (16-XX) 9 Calculus of variations and optimal control; optimization (49-XX) 9 Fluid mechanics (76-XX) 7 Nonassociative rings and algebras (17-XX) 7 Partial differential equations (35-XX) 6 Algebraic geometry (14-XX) 6 Category theory; homological algebra (18-XX) 6 Computer science (68-XX) 5 Differential geometry (53-XX) 5 Statistics (62-XX) 3 $$K$$-theory (19-XX) 3 Global analysis, analysis on manifolds (58-XX) 2 Dynamical systems and ergodic theory (37-XX) 2 Approximations and expansions (41-XX) 2 Algebraic topology (55-XX) 2 Optics, electromagnetic theory (78-XX) 2 Geophysics (86-XX) 1 History and biography (01-XX) 1 Linear and multilinear algebra; matrix theory (15-XX) 1 Real functions (26-XX) 1 Functional analysis (46-XX) 1 Operator theory (47-XX) 1 Probability theory and stochastic processes (60-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 1 Biology and other natural sciences (92-XX) 1 Systems theory; control (93-XX)
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-03-01T22:28:27 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.46623677015304565, "perplexity": 14141.857513346124}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178363072.47/warc/CC-MAIN-20210301212939-20210302002939-00077.warc.gz"}
|
https://indico.fnal.gov/event/20381/contributions/57323/
|
Indico will be rebooted on Tuesday, June 21st, at 5:30 pm Central Time. The downtime will be just few minutes. Thank you.
# New Perspectives 2019
Jun 10 – 11, 2019
Fermi National Accelerator Laboratory
US/Central timezone
## NOvA's far detector predictions and understanding key systematic uncertainties.
Jun 11, 2019, 3:05 PM
15m
One West (Fermi National Accelerator Laboratory)
### Speaker
Dr Ashley Back (Iowa State University)
### Description
NOvA continues as one of the leading long-baseline neutrino experiments, thanks to Fermilab's powerful 700 kW NuMI beam, which provides NOvA with a beam of predominantly muon neutrinos or antineutrinos. NOvA studies neutrino oscillations using two detectors, both constructed from plastic extrusions filled with liquid scintillator, placed 810 km apart and both slightly off-axis from the beam center. A key part of NOvA's approach is that we sample the NuMI beam with a near detector close to the target. This allows us to build an accurate far detector prediction and, since the detectors are functionally identical, largely cancel key flux and cross-section systematic uncertainties. The three-flavour long-baseline search probes undetermined physics parameters that describe neutrino mixing matrix, such as the mass hierarchy, CP violation in the lepton sector and the octant of $\theta_{23}$. Although statistical uncertainties dominate in our current results, understanding key sources of systematic uncertainty and their correlations is crucial in a joint fit to selected $\nu_{\mu}$ disappearance and $\nu_e$ appearance events, in both neutrino and antineutrino beam modes. In this talk, I will describe how we build up an accurate prediction at the far detector, using near detector data, and how we seek to understand key sources of systematic uncertainty by studying systematically shifted far detector predictions.
### Primary author
Dr Ashley Back (Iowa State University)
Slides
| 2022-06-25T07:59:18 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6828434467315674, "perplexity": 5376.914297784612}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103034877.9/warc/CC-MAIN-20220625065404-20220625095404-00723.warc.gz"}
|
https://www.legisquebec.gouv.qc.ca/en/version/cr/S-2.1,%20r.%202%20?code=se:32&history=20221128
|
### S-2.1, r. 2 - Regulation respecting joint sector-based associations on occupational health and safety
32. A sector-based association sends to the Commission, before 31 March of each year, an annual report of its activities containing the following information:
(1) the names of the signatories;
(2) the names of the members of the board of directors;
(3) the names of the members of the executive committee, where applicable;
(4) the number of representatives that each signatory may delegate to a meeting of signatories;
(5) the number of meetings held by the board of directors during the last year;
(6) where applicable, the number of meetings held by the executive committee during the last year;
(7) a summary description of the general objectives set for the last fiscal period;
(8) the program of activities carried out during the last fiscal period and the positive or negative factors that influenced its carrying out;
(9) the evaluation of the program of activities carried out with regard to the general objectives pursued during the last fiscal period;
(10) the number of health and safety committees in the sector concerned and the number of such committees in which the association intervened.
R.R.Q., 1981, c. S-2.1, r. 1, s. 32; O.C. 1712-92, s. 2.
| 2023-02-09T06:50:48 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8235390782356262, "perplexity": 4147.92169347576}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764501407.6/warc/CC-MAIN-20230209045525-20230209075525-00418.warc.gz"}
|
https://etl.beis.gov.uk/products/compressed-air-equipment/desiccant-air-dryers-energy-saving-controls
|
Tell us what you think about the new ETL website. Take the survey now.
# Desiccant Air Dryers with Energy Saving Controls
## 1.1 Scope
Desiccant air dryers are commonly fitted to compressed air systems to prevent moisture from condensing within pipe work and equipment. They are typically utilised where compressed air is needed at higher quality or with a lower dew point than can be achieved by a refrigerated air dryer.
They contain a desiccant material which absorbs the moisture and is then regenerated, for example, by blowing air through the dryer.
The direct energy usage of a desiccant air dryer typically increases the energy used in compressed air generation by between 10% and 25% depending on the product design and how it is controlled. Indirect energy usage, in the form of the pressure drop across the dryer and the compressed air used for purging can increase the overall energy usage in compressed air generation by between 20% and 50%. The aim of the Energy Technology List (ETL) Scheme is to encourage the purchase of higher efficiency models, which have low pressure drops across them. The aim of the ETL Scheme is to encourage the purchase of models which use energy efficient methods of desiccant regeneration, have low pressure drops across them and include energy savings controls.
To be eligible for inclusion on the ETL, products shall meet the requirements as set out below.
## 1.2 Definitions
Desiccant air dryers are products that are specifically designed to extract water vapour from industrial compressed air systems by absorbing moisture using a desiccant material which is then, for example, regenerated by blowing air through the dryer.
## 1.3 Requirements
### 1.3.1 Eligibility requirements
To be eligible, products must:
• Have a dew point rating of -40ºC i.e. Class 2 specifications for moisture removal in BS ISO 8573-1:2010.
• Utilise a regeneration method which is either heatless or internally/externally electrically heated or utilises a blower or vacuum system. Desiccant dryers that utilise steam, heat of compression or are heated in any way other than electrically are not eligible.
• Incorporate dew point sensing controls that automatically control the regeneration cycle to optimise the time between regenerations depending on the dew point of the exit air in a manner that reduces the energy consumption of the product.
• Not exceed the limits set out in the performance criteria below for the composite specific energy consumption (SEC) at 100% load (i.e. rated air flow), corrected for the pressure drop across the dryer and any compressed air used by the dryer for regeneration, purging and/or cooling.
• Conform with the requirements of The Pressure Equipment (Safety) Regulations 2016 in respect of their design, manufacture and testing procedures, or have an appropriate Conformity Assessment mark.
### 1.3.2 Performance requirements
Products must not exceed the values for composite specific energy consumption (SEC), corrected for the pressure drop across the dryer and any compressed air used by the dryer, set out in the Table 1.1 below at 100% load (i.e. rated air flow).
Table 1.1 Maximum Allowable Composite SEC in kW/m3/min
Percentage of full load (i.e. rated air flow) Maximum allowable Composite SEC (kW/m3/min) 100% <= 1.07
The composite SEC should be calculated as follows:
$$SEC = \frac{P + (1.67 \times \Delta p \times Q) + (5 \times C)}{Q - C}$$
Where:
P = Total electrical power consumed by air dryer, inclusive of any
external heaters, blowers, vacuum pumps or other associated
equipment, kW
Δp = Pressure drop across air dryer, bar
Q = Flow rate of air, m3/min
C = Total compressed air loss of air dryer for regeneration, purging, cooling
or any other purpose, m3/min
## 1.4 Measurement and Calculations
### 1.4.1 Measurement Standards and Test Requirements
All products must be tested in accordance with the procedures and test conditions laid down in BS ISO 7183:2007, which specifies how to measure the electrical power consumed by the product at full load, the pressure drop across the dryer, compressed air loss and the flow rate of air through the product. The test results should be presented in the format laid down in Annex B of BS ISO 7183-2:2007.
Products must also meet the Class 2 specifications for moisture removal in BS ISO 8573-1:2010, “Table 2 Compressed air purity classes for humidity and liquid water”
### 1.4.2 Rounding
For the avoidance of doubt composite SEC data must be presented to 2 decimal places. As an example, a product with a composite SEC of 1.08 at 100% of full load would be deemed to be a fail.
## 1.5 Verification for ETL Listing
Any of the following testing routes may be used to demonstrate the conformity of products against the requirements:
• In-house testing – Self-certified
• In-house testing – Self-tested and verified or cross-checked by an independent body
• Witnessed testing
• Independent testing
Further information regarding the routes can be found in Guidance Note 5 on the ETL product testing framework[1].
## 1.6 Conformity testing
Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements.
| 2022-01-24T10:07:30 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6401571035385132, "perplexity": 3626.041196092917}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304528.78/warc/CC-MAIN-20220124094120-20220124124120-00504.warc.gz"}
|
http://www.engr.mun.ca/~theo/Courses/AlgCoCo/recursionWonderland/Combinations.html
|
Copyright (c) Theodore Norvell 2017. Licence: Creative Commons Noncommercial Attribution International 4.0.
This is a Jupyter notebook. See How to use these notes.
# Combinations¶
## The problem¶
Alice has 5 tickets to the Red Queen's ball (in addition to her own). She has 10 friends she'd like to take. She wonders how many ways she can pick 5 friends out of a total of 10.
### A generalization¶
In general she'd like to know how many ways she can pick $r$ things out of a set of $n$ things. Of course this only makes sense if $0 \le r \le n$. Let's call this function combinations so combinations(n, r) will be the number of ways to pick a subset of size r out of a set of size n.
### A contract¶
We write a contract for the combinations function.
The contract is
def combinations( n, r ):
"""
Pre: r and n are integers such that 0 <= r and r <= n
Post: result == the number of subsets of size r of a set of size n
"""
## Problem analysis¶
### Alice's observation¶
Alice thinks about her 10 friends. Every subset will either contain her friend Bill the Lizard or it won't. First she thinks about how many sets of size 5 include Bill. There will be one such set for each way she could make a set of size 4 of out of the 9 remaining friends. That's $combinations( 9, 4 )$. What about the sets that don't include Bill. The number of those will be the number of sets of size 5 she can make out of her remaining 9 friends. That's #combinationd( 9, 5 )$Since each set either contains Bill or doesn't, we've accounted for all sets of size 5 that can by made from her 10 friends. And we haven't counted any twice. We have$combinations( 10, 5 ) = combinations( 9, 4 ) + combinations( 9, 5 )$Alice's idea generalizes to most pairs of numbers, but it doesn't work when$r=0$or when$r=n$. In general we have$combinations( n, r ) = combinations( n-1, r-1 ) + combinations( n-1, r )$provided$r>0$and$r
### We need a base case¶
The two cases that aren't dealt with by this rule can be dealt with easily enough.
Consider a set $S$ of size $n$. There is one subset of size 0, the empty set. So we have
$combinations(n, 0) = 1$ for all $n \ge 0$
And there is one subset of size $n$, the set $S$ itself. So we have
$combinations(n, n) = 1$ for all $n \ge 0$
So altogether we have three properties
1. $combinations(n, 0) = 1$ for all $n \ge 0$.
2. $combinations(n, n) = 1$ for all $n \ge 0$.
3. $combinations(n, r) = combinations( n-1, r-1 ) + combinations( n-1, r )$ for all $0 < r < n$.
### Is this a definition¶
These three properties uniquely define the function, we can see this by induction on $n$.
### Some tests¶
Based on the properties above we can make a table for testing.
n \ r 0 1 2 3 4 5 6
0 1
1 1 1
2 1 2 1
3 1 3 3 1
4 1 4 6 4 1
5 1 5 10 10 5 1
6 1 6 15 20 15 6 1
This table is the first 7 rows of an infinite table known as Pascal's triangle
## Design¶
Based on the problem analysis, we can write a design in pseudocode. In this case the pseudocode will look a lot like Python, so you can take this step if you want or skip it if you don't.
## Analyze design¶
Before coding, you should check that your design will work. Here is a checklist
• Is every case allowed by the precondition covered?
• Does the code do the right thing (i.e. return a result allowed by the postcondition) in each case?
• Is every recursive call smaller in some sense than its parent call?
## Code¶
Complete the following function
In [54]:
def combinations( n, r ):
"""
Pre: n and r are integers such that 0 <= r and r <= n
Post: result == the number of subsets of size r of a set of size n
"""
## Analyze code¶
If you wrote pseudocode, check that your design is consistant with the pseudocode. If you didn't write pseudocode, use the checklist above to check your code.
## Test¶
Below are some tests. After you define the function, you can run these tests and compare the answers with expected answers above.
In [55]:
combinations(0, 0)
In [56]:
combinations(4, 0)
In [57]:
combinations(4, 4)
In [58]:
combinations(6, 2)
Now let's compare your anSwers with the first 7 rows of Pascal's triangle
In [59]:
pascal = [ [1], [1, 1], [1, 2, 1], [1, 3, 3, 1], [1, 4, 6, 4, 1], [1, 5, 10, 10, 5, 1], [1, 6, 15, 20, 15, 6, 1]]
failures = set()
for n in range(0, 7) :
for r in range(0, n+1):
result = combinations(n,r)
print("c(", n, ",", r, ") =", result, end=" " )
if result != pascal[n][r]: failures.add( (n, r) )
print()
if len(failures) == 0 : print( "PASSED")
else: print( "FAILED on these inputs: ", failures )
c( 0 , 0 ) = None
c( 1 , 0 ) = None c( 1 , 1 ) = None
c( 2 , 0 ) = None c( 2 , 1 ) = None c( 2 , 2 ) = None
c( 3 , 0 ) = None c( 3 , 1 ) = None c( 3 , 2 ) = None c( 3 , 3 ) = None
c( 4 , 0 ) = None c( 4 , 1 ) = None c( 4 , 2 ) = None c( 4 , 3 ) = None c( 4 , 4 ) = None
c( 5 , 0 ) = None c( 5 , 1 ) = None c( 5 , 2 ) = None c( 5 , 3 ) = None c( 5 , 4 ) = None c( 5 , 5 ) = None
c( 6 , 0 ) = None c( 6 , 1 ) = None c( 6 , 2 ) = None c( 6 , 3 ) = None c( 6 , 4 ) = None c( 6 , 5 ) = None c( 6 , 6 ) = None
FAILED on these inputs: {(6, 6), (3, 0), (2, 1), (6, 2), (5, 1), (4, 0), (3, 3), (5, 5), (4, 4), (6, 3), (5, 0), (2, 2), (4, 1), (1, 1), (6, 4), (3, 2), (0, 0), (5, 4), (6, 0), (4, 2), (1, 0), (6, 5), (5, 3), (6, 1), (3, 1), (2, 0), (4, 3), (5, 2)}
# My Solution¶
## Design¶
Here is my pseudo code
function $combinations( n : nat, r : nat )$
pre $0 \le r \le n$
post result = the number of subsets of size r of a set of size n
if $r = 0$ then 1
| $r = n$ then 1
| $0 < r < n$ then $combinations( n-1, r-1) + combinations( n-1, r)$
end if
## Code¶
And here is the Python 3 code
In [60]:
def combinationsMine( n, r ):
"""
Pre: n and r are integers such that 0 <= r and r <= n
Post: result == the number of subsets of size r of a set of size n
"""
assert isinstance(n, int) and n >= 0
assert isinstance(r, int) and 0 <= r and r <= n
if r == 0: return 1
elif r == n: return 1
else: return combinationsMine(n-1, r-1) + combinationsMine(n-1, r)
## Test¶
In [53]:
combinationsMine(0, 0)
Out[53]:
1
In [44]:
combinationsMine(4, 0)
Out[44]:
1
In [45]:
combinationsMine(4, 4)
Out[45]:
1
In [46]:
combinationsMine(6, 2)
Out[46]:
15
Next we'll compare with Pascal's triangle.
In [50]:
failures = set()
for n in range(0, 7) :
for r in range(0, n+1):
result = combinationsMine(n,r)
print("c(", n, ",", r, ") =", result, end=" " )
if result != pascal[n][r]: failures.add( (n, r) )
print()
if len(failures) == 0 : print( "PASSED")
else: print( "FAILED on these inputs: ", failures )
c( 0 , 0 ) = 1
c( 1 , 0 ) = 1 c( 1 , 1 ) = 1
c( 2 , 0 ) = 1 c( 2 , 1 ) = 2 c( 2 , 2 ) = 1
c( 3 , 0 ) = 1 c( 3 , 1 ) = 3 c( 3 , 2 ) = 3 c( 3 , 3 ) = 1
c( 4 , 0 ) = 1 c( 4 , 1 ) = 4 c( 4 , 2 ) = 6 c( 4 , 3 ) = 4 c( 4 , 4 ) = 1
c( 5 , 0 ) = 1 c( 5 , 1 ) = 5 c( 5 , 2 ) = 10 c( 5 , 3 ) = 10 c( 5 , 4 ) = 5 c( 5 , 5 ) = 1
c( 6 , 0 ) = 1 c( 6 , 1 ) = 6 c( 6 , 2 ) = 15 c( 6 , 3 ) = 20 c( 6 , 4 ) = 15 c( 6 , 5 ) = 6 c( 6 , 6 ) = 1
PASSED
# Going further¶
The straightforward recursive solution that I've used is very inefficient. I'm going to ignore this problem for now. The point of these exercises is to get comfortable with creating correct recursive solutions without worrying about efficiency. Later we'll come back to the problem of making this solution efficient by using a technique called "memoization".
| 2017-11-18T12:18:46 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6178110241889954, "perplexity": 641.5388637746195}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-47/segments/1510934804881.4/warc/CC-MAIN-20171118113721-20171118133721-00146.warc.gz"}
|
https://www.itl.nist.gov/div898/software/dataplot/refman2/auxillar/pbendmv.htm
|
Dataplot Vol 2 Vol 1
# PERCENTAGE BEND MIDVARIANCE
Name:
PERCENTAGE BEND MIDVARIANCE (LET)
Type:
Let Subcommand
Purpose:
Compute the percentage bend midvariance for a variable.
Description:
Mosteller and Tukey (see Reference section below) define two types of robustness:
1. resistance means that changing a small part, even by a large amount, of the data does not cause a large change in the estimate
2. robustness of efficiency means that the statistic has high efficiency in a variety of situations rather than in any one situation. Efficiency means that the estimate is close to optimal estimate given that we know what distribution that the data comes from. A useful measure of efficiency is:
Efficiency = (lowest variance feasible)/ (actual variance)
Many statistics have one of these properties. However, it can be difficult to find statistics that are both resistant and have robustness of efficiency.
For scale estimaors, the variance is an optimal estimator for Gaussian data. However, it is not resistant and it does not have robustness of efficiency. The rationale for this estimate is given in these references.
The percentage bend midvariance estimator, discussed in Shoemaker and Hettmansperger and also by Wilcox, is both resistant and robust of efficiency.
The percentage bend midvariance of a a variable X is computed as follows:
1. Set m = [(1 - $$\beta$$ )*n + 0.5]. This is the value of (1 - $$\beta$$ )*n + 0.5 rounded down to the nearest integer.
2. Let Wi = |Xi - M| for i = 1, ..., n where M is the median of X.
3. Sort the Wi in ascending order.
4. $$\hat{W}_{x}$$ = W(m) (i. e., the m-th order statistic). W(m) is the estimate of the (1-$$\beta$$) quantile of W.
5. $$Y_i = \frac{X_i - M}{\hat{\omega}_{\beta}}$$
6. $$A(i) = \log(x_{i})$$
7. $$\Psi(x) = \max[-1, \min(1,x)]$$
8. $$s_{pb} = \frac {n \hat{\omega}_{\beta} \sum_{i=1}^{n}{ \left( \Psi(Y_{i}) \right) ^2} } {(\sum_{i=1}^{n}{a_{i}})^{2} }$$
The value of $$\beta$$ is selected between 0 and 0.5. Higher values of $$\beta$$ is selected result in a higher breakdown point at the expense of lower efficiency.
Syntax:
LET <par> = PERCENTAGE BEND MIDVARIANCE <y> <SUBSET/EXCEPT/FOR qualification>
where <y> is the response variable;
<par> is a parameter where the computed percentage bend midvariance is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
LET A = PERCENTAGE BEND MIDVARIANCE Y1
LET A = PERCENTAGE BEND MIDVARIANCE Y1 SUBSET TAG > 2
Note:
To set the value of $$\beta$$, enter the command
LET BETA = <value>
where <value> is greater than 0 and less than or equal to 0.5. The default value for $$\beta$$ is 0.1.
Note:
Dataplot statistics can be used in a number of commands. For details, enter
Default:
None
Synonyms:
None
Related Commands:
PERCENTAGE BEND CORRELATION = Compute the percentage bend correlation of a variable. BIWEIGHT MIDCORRELATION = Compute a biweight correlation estimate of a variable. WINSORIZED CORRELATION = Compute a Winsorized correlation estimate of a variable. CORRELATION = Compute the correlation between two variables. RANK CORRELATION = Compute the rank correlation between two variables. VARIANCE = Compute the variance of a variable. STATISTIC PLOT = Generate a statistic versus group plot for a given statistic.
References:
Shoemaker and Hettmansperger (1982), "Robust Estimates of and Tests for the One- and Two-Sample Scale Models", Biometrika 69, pp. 47-54.
Rand Wilcox (1997), "Introduction to Robust Estimation and Hypothesis Testing", Academic Press.
Mosteller and Tukey (1977), "Data Analysis and Regression: A Second Course in Statistics", Addison-Wesley, pp. 203-209.
Applications:
Robust Data Analysis
Implementation Date:
2002/07
Program 1:
LET Y1 = NORMAL RANDOM NUMBERS FOR I = 1 1 100
LET Y2 = LOGISTIC RANDOM NUMBERS FOR I = 1 1 100
LET Y3 = CAUCHY RANDOM NUMBERS FOR I = 1 1 100
LET Y4 = DOUBLE EXPONENTIAL RANDOM NUMBERS FOR I = 1 1 100
LET A1 = PERCENTAGE BEND MIDVARIANCE Y1
LET A2 = PERCENTAGE BEND MIDVARIANCE Y2
LET A3 = PERCENTAGE BEND MIDVARIANCE Y3
LET A4 = PERCENTAGE BEND MIDVARIANCE Y4
Program 2:
MULTIPLOT 2 2
MULTIPLOT CORNER COORDINATES 0 0 100 100
MULTIPLOT SCALE FACTOR 2
X1LABEL DISPLACEMENT 12
.
LET Y1 = NORMAL RANDOM NUMBERS FOR I = 1 1 200
LET Y2 = CAUCHY RANDOM NUMBERS FOR I = 1 1 200
.
BOOTSTRAP SAMPLES 500
BOOTSTRAP PERCENTAGE BEND MIDVARIANCE PLOT Y1
X1LABEL B025 = ^B025, B975=^B975
HISTOGRAM YPLOT
X1LABEL
.
BOOTSTRAP PERCENTAGE BEND MIDVARIANCE PLOT Y1
X1LABEL B025 = ^B025, B975=^B975
HISTOGRAM YPLOT
.
END OF MULTIPLOT
JUSTIFICATION CENTER
MOVE 50 96
TEXT PERCENTAGE BEND MIDVARIANCE BOOTSTRAP: NORMAL
MOVE 50 46
TEXT PERCENTAGE BEND MIDVARIANCE BOOTSTRAP: CAUCHY
NIST is an agency of the U.S. Commerce Department.
Date created: 07/22/2002
Last updated: 10/07/2016
| 2018-06-18T15:45:55 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.908129870891571, "perplexity": 4742.336306155581}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267860570.57/warc/CC-MAIN-20180618144750-20180618164750-00246.warc.gz"}
|
https://zbmath.org/authors/?q=rv%3A1649
|
## Stanković, Bogoljub
Compute Distance To:
Author ID: stankovic.bogoljub Published as: Stanković, B.; Stanković, Bogoljub; Stankovic, B.; Stankovic, Bogoljub; Stankovič, Bogoljub; Stankovich, Bogoljub more...less External Links: MGP · Wikidata · Math-Net.Ru · dblp · IdRef
Documents Indexed: 173 Publications since 1953, including 8 Books 5 Contributions as Editor Reviewing Activity: 171 Reviews Biographic References: 5 Publications Co-Authors: 17 Co-Authors with 52 Joint Publications 444 Co-Co-Authors
all top 5
### Co-Authors
124 single-authored 25 Atanackovic, Teodor M. 21 Pilipović, Stevan 2 Skendzic, Marija 2 Takači, Đurđica 2 Zorica, Dusan 1 Budimčević, M. 1 Despotovic, D. 1 Dolićanin-Đekić, Diana 1 Hadžić, Olga 1 Herceg, Dragoslav 1 Jovin, M. 1 Nikolić-Despotović, Danica 1 Pap, Endre 1 Sad, Novi 1 Takači, Arpad 1 Vindas, Jasson 1 Vladimirov, Vasiliĭ Sergeevich
all top 5
### Serials
26 Publications de l’Institut Mathématique. Nouvelle Série 18 Bulletin. Classe des Sciences Mathématiques et Naturelles. Sciences Mathématiques 16 Zbornik Radova. Prirodno-Matematichkog Fakulteta. Serija za Matematiku 7 Académie Serbe des Sciences, Publications de l’Institut Mathématique 6 Fractional Calculus & Applied Analysis 5 Integral Transforms and Special Functions 5 Zbornik Radova (Beograd) 4 Studia Mathematica 4 Matematichki Vesnik. New Series 3 Applicable Analysis 3 Journal of Mathematical Analysis and Applications 3 International Journal of Mathematics and Mathematical Sciences 2 Matematički Vesnik 2 Zeitschrift für Analysis und ihre Anwendungen 2 Novi Sad Journal of Mathematics 2 ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik 2 Mechanical Engineering and Solid Mechanics Series 1 Acta Mechanica 1 Mathematica Balkanica 1 Russian Mathematical Surveys 1 Bulletin Mathématique de la Société des Sciences Mathématiques de la République Socialiste de Roumanie. Nouvelle Série 1 Journal of Differential Equations 1 Journal of the London Mathematical Society. Second Series 1 Mechanics Research Communications 1 Proceedings of the American Mathematical Society 1 Proceedings of the Japan Academy. Series A 1 Rendiconti del Seminario Matematico della Università di Padova 1 PLISKA. Studia Mathematica Bulgarica 1 Acta Mathematica Hungarica 1 European Journal of Applied Mathematics 1 Mathematica Pannonica 1 YUJOR. Yugoslav Journal of Operations Research 1 Glasnik Matematički. Serija III 1 Journal of Physics A: Mathematical and General 1 Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences 1 Serdica 1 Mathematica Montisnigri 1 Mathematics and Mechanics of Solids 1 Theoretical and Applied Mechanics 1 Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences, Paris 1 Bulletin de la Société des Mathématiciens et Physiciens de la R. P. de Serbie 1 Annales Societatis Mathematicae Polonae 1 Teubner-Texte zur Mathematik 1 Series on Analysis, Applications and Computation 1 International Journal of Dynamical Systems and Differential Equations
all top 5
### Fields
68 Functional analysis (46-XX) 33 Integral transforms, operational calculus (44-XX) 28 Ordinary differential equations (34-XX) 23 Real functions (26-XX) 18 Mechanics of deformable solids (74-XX) 16 Partial differential equations (35-XX) 6 General and overarching topics; collections (00-XX) 5 Integral equations (45-XX) 5 Numerical analysis (65-XX) 4 Sequences, series, summability (40-XX) 4 Approximations and expansions (41-XX) 3 History and biography (01-XX) 3 Operator theory (47-XX) 3 Classical thermodynamics, heat transfer (80-XX) 2 Special functions (33-XX) 2 Mechanics of particles and systems (70-XX) 1 Algebraic geometry (14-XX) 1 Functions of a complex variable (30-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Dynamical systems and ergodic theory (37-XX) 1 Abstract harmonic analysis (43-XX) 1 Calculus of variations and optimal control; optimization (49-XX) 1 Fluid mechanics (76-XX)
### Citations contained in zbMATH Open
66 Publications have been cited 530 times in 399 Documents Cited by Year
Fractional calculus with applications in mechanics. Vibrations and diffusion processes. Zbl 1291.74001
Atanacković, Teodor M.; Pilipović, Steven; Stanković, Bogoljub; Zorica, Dušan
2014
Fractional calculus with applications in mechanics. Wave propagation, impact and variational principles. Zbl 1293.74001
Atanacković, Teodor M.; Pilipović, Stevan; Stanković, Bogoljub; Zorica, Dušan
2014
On a numerical scheme for solving differential equations of fractional order. Zbl 1258.65103
Atanackovic, T. M.; Stankovic, B.
2008
On a system of differential equations with fractional derivatives arising in rod theory. Zbl 1059.35011
Atanackovic, Teodor M.; Stankovic, Bogoljub
2004
Generalized wave equation in nonlocal elasticity. Zbl 1397.74100
Atanackovic, T. M.; Stankovic, B.
2009
On a class of differential equations with left and right fractional derivatives. Zbl 1131.34003
Atanackovic, T. M.; Stankovic, B.
2007
On the function of E.M. Wright. Zbl 0204.08404
Stanković, B.
1970
Asymptotic behaviour and Stieltjes transformation of distributions. Zbl 0756.46020
Pilipović, Stevan; Stanković, Bogoljub; Takači, Arpad
1990
An expansion formula for fractional derivatives and its application. Zbl 1128.26003
Atanackovic, T. M.; Stankovic, B.
2004
On a differential equation with left and right fractional derivatives. Zbl 1136.26301
Atanackovic, Teodor M.; Stankovich, Bogoljub
2007
Dynamics of a viscoelastic rod of fractional derivative type. Zbl 1008.74051
Atanackovic, T. M.; Stankovic, B.
2002
Asymptotic behavior of generalized functions. Zbl 1259.46001
Pilipović, Stevan; Stanković, Bogoljub; Vindas, Jasson
2012
An equation with left and right fractional derivatives. Zbl 1246.26008
Stanković, B.
2006
Cauchy problems for some classes of linear fractional differential equations. Zbl 1312.34006
Atanackovic, Teodor; Dolicanin, Diana; Pilipovic, Stevan; Stankovic, Bogoljub
2014
Linear fractional differential equation with variable coefficients. I. Zbl 1313.26011
Atanacković, T. M.; Stanković, B.
2013
Linear fractional differential equation with variable coefficients. II. Zbl 1488.34019
Atanacković, T. M.; Stanković, B.
2014
Tauberian theorems for integral transforms of distributions. Zbl 0921.46035
Pilipović, S.; Stanković, B.
1997
On an inequality arising in fractional oscillator theory. Zbl 1072.26008
Stankovic, Bogoljub; Atanackovic, Teodor M.
2004
An equation in the left and right fractional derivatives of the same order. Zbl 1274.34013
Stanković, B.
2008
Abelian and Tauberian theorems for Stieltjes transforms of distributions. Zbl 0612.46036
Stanković, B.
1985
Wiener Tauberian theorems for distributions. Zbl 0739.46032
Pilipović, S.; Stanković, B.
1993
Some properties of Wright’s function. Zbl 0343.33011
Gajic, Lj.; Stankovic, B.
1976
Abel-Tauberian type theorem for the Laplace transform of hyperfunctions. Zbl 1062.46031
Stanković, B.
2004
On a model of a viscoelastic rod. Zbl 1169.74465
Stankovic, Bogoljub; Atanackovic, Teodor M.
2001
S-asymptotic of a distribution. Zbl 0812.46030
Pilipović, Stevan; Stanković, Bogoljub
1989
Operator linear differential equation of order m. Zbl 0164.44901
Stankovic, B.
1969
L’equation différentielle vectorielle. Zbl 0165.46702
Stankovic, B.
1966
A system of partial differential equations with fractional derivatives. Zbl 1061.46038
Stanković, B.
2002
On a viscoelastic rod with constitutive equation containing fractional derivatives of two different orders. Zbl 1066.74037
Stankovic, B.; Atanackovic, T. M.
2004
Dynamics of a rod made of generalized Kelvin-Voigt viscoelastic material. Zbl 1067.74037
Stankovic, B.; Atanackovic, T. M.
2002
Wiener Tauberian theorems for ultradistributions. Zbl 0827.46033
Pilipović, S.; Stanković, B.
1994
Large linear equation with left and right fractional derivatives in a finite interval. Zbl 1299.26015
Stanković, B.
2011
Three topics from contemporary mathematics. Zbl 0870.00025
1997
Taylor expansion for generalized functions. Zbl 0889.46036
Stanković, B.
1996
Quasi-asymptotics and $$S$$-asymptotics of ultradistributions. Zbl 0853.46032
Pilipović, S.; Stanković, B.
1995
On the solvability of algebraic equations in the field of Mikusinski’s operators. Zbl 0229.44010
Stankovic, B.
1971
Inversion et invariantes de la transformation généralisée de Hankel. Zbl 0066.09202
Stanković, B.
1955
S-asymptotic expansion of distribution. Zbl 0647.41025
Stankovic, Bogoljub
1988
Differentialgleichungen in lokal konvexen Räumen. Zbl 0236.34060
Stankovic, B.
1970
Two theorems on differential equations in locally convex spaces. Zbl 0253.34032
Stankovic, B.
1972
Sur une fonction du calcul opérationnel. Zbl 0056.10301
Stanković, Bogoljub
1954
L’élément maximal d’une matrice speciale. Zbl 0158.13303
Stankovic, B.; Tosic, R.
1967
Some theorems on fixed points and their applications. Zbl 0203.14602
Stanković, B.
1969
Espace $$C_ s$$, le sous-espace de opérateurs de J. Mikusiński. Zbl 0204.12604
Stanković, B.
1966
Some theorems on the fixed point in locally convex spaces. Zbl 0219.47053
1970
Wiener-type Tauberian theorems for Fourier hyperfunctions. Zbl 1038.46030
Pilipović, S.; Stanković, B.
2002
Structural theorems for the $$S$$-asymptotic and quasiasymptotic of distributions. Zbl 0796.46021
Pilipović, S.; Stanković, B.
1993
Differential equation with fractional derivative and nonconstant coefficients. Zbl 1046.34010
Stanković, B.
2002
Generalized functions and their applications. Zbl 1013.46027
Stanković, Bogoljub
1998
Laplace transform of Laplace hyperfunctions and its applications. Zbl 1009.46026
Stanković, Bogoljub
2001
Asymptotics of regular convolution quotients. Zbl 0765.44003
Stanković, Bogoljub
1992
Abelian theorems for integral transforms of distributions. Zbl 0828.46039
Stanković, Bogoljub
1993
Structural problems of the asymptotic behaviour of generalized functions. Zbl 0846.46026
Stanković, Bogoljub
1993
Stanković, B.
1995
A theory of linear differential equations with fractional derivatives. Zbl 1289.34007
Atanacković, T. M.; Pilipović, S.; Stanković, B.
2012
Convergence in the space of Fourier hyperfunctions. Zbl 0904.46028
Pilipović, Stevan; Stanković, Bogoljub
1997
Asymptotic Taylor expansion for Fourier hyperfunctions. Zbl 0905.46027
Stanković, B.
1997
Asymptotic almost periodic distributions, structural theorem. Zbl 0793.46018
Stanković, Bogoljub
1993
Abelian theorem for the Stieltjes transform of distributions. Zbl 0742.46024
Stanković, Bogoljub
1990
Theorems of Tauberian type for measures. Zbl 0592.46039
Stanković, B.
1985
The asymptotic of elements belonging to $${\mathcal D}_{L^ p}$$ and $${\mathcal D}'_{L^ p}$$. Zbl 0692.46035
Stanković, Bogoljub
1988
The structure of a convergent family of Fourier hyperfunctions. Zbl 0933.46030
Pilipović, S.; Stanković, B.
1998
Properties of ultradistributions having the $$S$$-asymptotics. Zbl 0903.46035
Pilipović, S.; Stanković, B.
1996
Laplace transform of functions defined on a bounded interval. Zbl 1456.44002
Stanković, Bogoljub
2015
Generalized solutions to a linear discontinuous differential equation. Zbl 1154.34309
Stanković, B.; Atanacković, T. M.
2006
Theorems of the generalized Tauberian type for measures. Zbl 0578.46036
Stanković, Bogoljub
1983
Laplace transform of functions defined on a bounded interval. Zbl 1456.44002
Stanković, Bogoljub
2015
Fractional calculus with applications in mechanics. Vibrations and diffusion processes. Zbl 1291.74001
Atanacković, Teodor M.; Pilipović, Steven; Stanković, Bogoljub; Zorica, Dušan
2014
Fractional calculus with applications in mechanics. Wave propagation, impact and variational principles. Zbl 1293.74001
Atanacković, Teodor M.; Pilipović, Stevan; Stanković, Bogoljub; Zorica, Dušan
2014
Cauchy problems for some classes of linear fractional differential equations. Zbl 1312.34006
Atanackovic, Teodor; Dolicanin, Diana; Pilipovic, Stevan; Stankovic, Bogoljub
2014
Linear fractional differential equation with variable coefficients. II. Zbl 1488.34019
Atanacković, T. M.; Stanković, B.
2014
Linear fractional differential equation with variable coefficients. I. Zbl 1313.26011
Atanacković, T. M.; Stanković, B.
2013
Asymptotic behavior of generalized functions. Zbl 1259.46001
Pilipović, Stevan; Stanković, Bogoljub; Vindas, Jasson
2012
A theory of linear differential equations with fractional derivatives. Zbl 1289.34007
Atanacković, T. M.; Pilipović, S.; Stanković, B.
2012
Large linear equation with left and right fractional derivatives in a finite interval. Zbl 1299.26015
Stanković, B.
2011
Generalized wave equation in nonlocal elasticity. Zbl 1397.74100
Atanackovic, T. M.; Stankovic, B.
2009
On a numerical scheme for solving differential equations of fractional order. Zbl 1258.65103
Atanackovic, T. M.; Stankovic, B.
2008
An equation in the left and right fractional derivatives of the same order. Zbl 1274.34013
Stanković, B.
2008
On a class of differential equations with left and right fractional derivatives. Zbl 1131.34003
Atanackovic, T. M.; Stankovic, B.
2007
On a differential equation with left and right fractional derivatives. Zbl 1136.26301
Atanackovic, Teodor M.; Stankovich, Bogoljub
2007
An equation with left and right fractional derivatives. Zbl 1246.26008
Stanković, B.
2006
Generalized solutions to a linear discontinuous differential equation. Zbl 1154.34309
Stanković, B.; Atanacković, T. M.
2006
On a system of differential equations with fractional derivatives arising in rod theory. Zbl 1059.35011
Atanackovic, Teodor M.; Stankovic, Bogoljub
2004
An expansion formula for fractional derivatives and its application. Zbl 1128.26003
Atanackovic, T. M.; Stankovic, B.
2004
On an inequality arising in fractional oscillator theory. Zbl 1072.26008
Stankovic, Bogoljub; Atanackovic, Teodor M.
2004
Abel-Tauberian type theorem for the Laplace transform of hyperfunctions. Zbl 1062.46031
Stanković, B.
2004
On a viscoelastic rod with constitutive equation containing fractional derivatives of two different orders. Zbl 1066.74037
Stankovic, B.; Atanackovic, T. M.
2004
Dynamics of a viscoelastic rod of fractional derivative type. Zbl 1008.74051
Atanackovic, T. M.; Stankovic, B.
2002
A system of partial differential equations with fractional derivatives. Zbl 1061.46038
Stanković, B.
2002
Dynamics of a rod made of generalized Kelvin-Voigt viscoelastic material. Zbl 1067.74037
Stankovic, B.; Atanackovic, T. M.
2002
Wiener-type Tauberian theorems for Fourier hyperfunctions. Zbl 1038.46030
Pilipović, S.; Stanković, B.
2002
Differential equation with fractional derivative and nonconstant coefficients. Zbl 1046.34010
Stanković, B.
2002
On a model of a viscoelastic rod. Zbl 1169.74465
Stankovic, Bogoljub; Atanackovic, Teodor M.
2001
Laplace transform of Laplace hyperfunctions and its applications. Zbl 1009.46026
Stanković, Bogoljub
2001
Generalized functions and their applications. Zbl 1013.46027
Stanković, Bogoljub
1998
The structure of a convergent family of Fourier hyperfunctions. Zbl 0933.46030
Pilipović, S.; Stanković, B.
1998
Tauberian theorems for integral transforms of distributions. Zbl 0921.46035
Pilipović, S.; Stanković, B.
1997
Three topics from contemporary mathematics. Zbl 0870.00025
1997
Convergence in the space of Fourier hyperfunctions. Zbl 0904.46028
Pilipović, Stevan; Stanković, Bogoljub
1997
Asymptotic Taylor expansion for Fourier hyperfunctions. Zbl 0905.46027
Stanković, B.
1997
Taylor expansion for generalized functions. Zbl 0889.46036
Stanković, B.
1996
Properties of ultradistributions having the $$S$$-asymptotics. Zbl 0903.46035
Pilipović, S.; Stanković, B.
1996
Quasi-asymptotics and $$S$$-asymptotics of ultradistributions. Zbl 0853.46032
Pilipović, S.; Stanković, B.
1995
Stanković, B.
1995
Wiener Tauberian theorems for ultradistributions. Zbl 0827.46033
Pilipović, S.; Stanković, B.
1994
Wiener Tauberian theorems for distributions. Zbl 0739.46032
Pilipović, S.; Stanković, B.
1993
Structural theorems for the $$S$$-asymptotic and quasiasymptotic of distributions. Zbl 0796.46021
Pilipović, S.; Stanković, B.
1993
Abelian theorems for integral transforms of distributions. Zbl 0828.46039
Stanković, Bogoljub
1993
Structural problems of the asymptotic behaviour of generalized functions. Zbl 0846.46026
Stanković, Bogoljub
1993
Asymptotic almost periodic distributions, structural theorem. Zbl 0793.46018
Stanković, Bogoljub
1993
Asymptotics of regular convolution quotients. Zbl 0765.44003
Stanković, Bogoljub
1992
Asymptotic behaviour and Stieltjes transformation of distributions. Zbl 0756.46020
Pilipović, Stevan; Stanković, Bogoljub; Takači, Arpad
1990
Abelian theorem for the Stieltjes transform of distributions. Zbl 0742.46024
Stanković, Bogoljub
1990
S-asymptotic of a distribution. Zbl 0812.46030
Pilipović, Stevan; Stanković, Bogoljub
1989
S-asymptotic expansion of distribution. Zbl 0647.41025
Stankovic, Bogoljub
1988
The asymptotic of elements belonging to $${\mathcal D}_{L^ p}$$ and $${\mathcal D}'_{L^ p}$$. Zbl 0692.46035
Stanković, Bogoljub
1988
Abelian and Tauberian theorems for Stieltjes transforms of distributions. Zbl 0612.46036
Stanković, B.
1985
Theorems of Tauberian type for measures. Zbl 0592.46039
Stanković, B.
1985
Theorems of the generalized Tauberian type for measures. Zbl 0578.46036
Stanković, Bogoljub
1983
Some properties of Wright’s function. Zbl 0343.33011
Gajic, Lj.; Stankovic, B.
1976
Two theorems on differential equations in locally convex spaces. Zbl 0253.34032
Stankovic, B.
1972
On the solvability of algebraic equations in the field of Mikusinski’s operators. Zbl 0229.44010
Stankovic, B.
1971
On the function of E.M. Wright. Zbl 0204.08404
Stanković, B.
1970
Differentialgleichungen in lokal konvexen Räumen. Zbl 0236.34060
Stankovic, B.
1970
Some theorems on the fixed point in locally convex spaces. Zbl 0219.47053
1970
Operator linear differential equation of order m. Zbl 0164.44901
Stankovic, B.
1969
Some theorems on fixed points and their applications. Zbl 0203.14602
Stanković, B.
1969
L’élément maximal d’une matrice speciale. Zbl 0158.13303
Stankovic, B.; Tosic, R.
1967
L’equation différentielle vectorielle. Zbl 0165.46702
Stankovic, B.
1966
Espace $$C_ s$$, le sous-espace de opérateurs de J. Mikusiński. Zbl 0204.12604
Stanković, B.
1966
Inversion et invariantes de la transformation généralisée de Hankel. Zbl 0066.09202
Stanković, B.
1955
Sur une fonction du calcul opérationnel. Zbl 0056.10301
Stanković, Bogoljub
1954
all top 5
all top 5
### Cited in 151 Serials
28 Fractional Calculus & Applied Analysis 19 Applied Mathematics and Computation 14 Advances in Difference Equations 13 Journal of Mathematical Analysis and Applications 12 Applied Mathematical Modelling 11 Acta Mechanica 11 Chaos, Solitons and Fractals 11 Integral Transforms and Special Functions 10 Nonlinear Dynamics 10 Communications in Nonlinear Science and Numerical Simulation 9 Computers & Mathematics with Applications 7 Meccanica 6 Computational and Applied Mathematics 5 Mathematical Problems in Engineering 5 International Journal of Applied and Computational Mathematics 5 Vestnik KRAUNTS. Fiziko-Matematicheskie Nauki 4 Journal of Computational Physics 4 Journal of Computational and Applied Mathematics 4 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 4 Zeitschrift für Analysis und ihre Anwendungen 4 Applied Numerical Mathematics 4 Applied Mathematics Letters 4 Archive of Applied Mechanics 4 Continuum Mechanics and Thermodynamics 4 Differential Equations 4 Boundary Value Problems 4 Advances in Applied Mathematics and Mechanics 3 Applicable Analysis 3 Journal of Mathematical Physics 3 Mathematical Notes 3 Physica A 3 Journal of Differential Equations 3 Acta Mathematica Hungarica 3 Fractals 3 Mathematics and Mechanics of Solids 3 Journal of Applied Mathematics and Computing 3 Theoretical and Applied Mechanics 3 International Journal of Biomathematics 3 Philosophical Transactions of the Royal Society of London. A. Mathematical, Physical and Engineering Sciences 2 Mathematical Methods in the Applied Sciences 2 Reports on Mathematical Physics 2 Acta Applicandae Mathematicae 2 Journal of Scientific Computing 2 Numerical Algorithms 2 International Journal of Computer Mathematics 2 Turkish Journal of Mathematics 2 Engineering Analysis with Boundary Elements 2 Journal of Vibration and Control 2 Abstract and Applied Analysis 2 Journal of Inequalities and Applications 2 ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik 2 Chaos 2 Journal of Interdisciplinary Mathematics 2 Discrete and Continuous Dynamical Systems. Series B 2 Journal of Applied Mathematics 2 Acta Mathematica Scientia. Series B. (English Edition) 2 Mediterranean Journal of Mathematics 2 Proceedings of the Steklov Institute of Mathematics 2 Applicable Analysis and Discrete Mathematics 2 Tbilisi Mathematical Journal 2 Advances in Mathematical Physics 2 Advances in Nonlinear Analysis 2 Journal of Mathematical Modeling 1 International Journal of Engineering Science 1 Journal d’Analyse Mathématique 1 Journal of the Franklin Institute 1 Lithuanian Mathematical Journal 1 Physics Letters. A 1 Wave Motion 1 ZAMP. Zeitschrift für angewandte Mathematik und Physik 1 Bulletin of the Polish Academy of Sciences. Technical Sciences 1 Czechoslovak Mathematical Journal 1 Functional Analysis and its Applications 1 International Journal of Mathematics and Mathematical Sciences 1 Journal of Applied Probability 1 Journal of Approximation Theory 1 Journal of Number Theory 1 Journal of Optimization Theory and Applications 1 Journal of Soviet Mathematics 1 Mathematics and Computers in Simulation 1 Mechanics Research Communications 1 Numerical Functional Analysis and Optimization 1 Proceedings of the American Mathematical Society 1 Proceedings of the Edinburgh Mathematical Society. Series II 1 Quaestiones Mathematicae 1 Rendiconti del Seminario Matematico della Università di Padova 1 Results in Mathematics 1 SIAM Journal on Control and Optimization 1 SIAM Journal on Numerical Analysis 1 Tôhoku Mathematical Journal. Second Series 1 Optimal Control Applications & Methods 1 Statistics & Probability Letters 1 Computational Mechanics 1 European Journal of Applied Mathematics 1 Computational Mathematics and Modeling 1 MSCS. Mathematical Structures in Computer Science 1 Annals of Physics 1 Proceedings of the Indian Academy of Sciences. Mathematical Sciences 1 Indagationes Mathematicae. New Series 1 Cybernetics and Systems Analysis ...and 51 more Serials
all top 5
### Cited in 42 Fields
154 Ordinary differential equations (34-XX) 150 Real functions (26-XX) 117 Partial differential equations (35-XX) 67 Mechanics of deformable solids (74-XX) 65 Numerical analysis (65-XX) 41 Functional analysis (46-XX) 32 Calculus of variations and optimal control; optimization (49-XX) 28 Special functions (33-XX) 27 Operator theory (47-XX) 26 Integral equations (45-XX) 22 Harmonic analysis on Euclidean spaces (42-XX) 21 Integral transforms, operational calculus (44-XX) 18 Biology and other natural sciences (92-XX) 17 Probability theory and stochastic processes (60-XX) 15 Systems theory; control (93-XX) 14 Classical thermodynamics, heat transfer (80-XX) 13 Fluid mechanics (76-XX) 12 Sequences, series, summability (40-XX) 9 Dynamical systems and ergodic theory (37-XX) 9 Mechanics of particles and systems (70-XX) 8 Approximations and expansions (41-XX) 7 Functions of a complex variable (30-XX) 6 Global analysis, analysis on manifolds (58-XX) 5 Statistical mechanics, structure of matter (82-XX) 3 History and biography (01-XX) 3 Information and communication theory, circuits (94-XX) 2 Combinatorics (05-XX) 2 Number theory (11-XX) 2 Difference and functional equations (39-XX) 2 Optics, electromagnetic theory (78-XX) 2 Quantum theory (81-XX) 2 Operations research, mathematical programming (90-XX) 1 General and overarching topics; collections (00-XX) 1 Order, lattices, ordered algebraic structures (06-XX) 1 Linear and multilinear algebra; matrix theory (15-XX) 1 Measure and integration (28-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Abstract harmonic analysis (43-XX) 1 Differential geometry (53-XX) 1 General topology (54-XX) 1 Statistics (62-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2023-02-04T21:38:04 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4715389609336853, "perplexity": 7436.835536904469}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500154.33/warc/CC-MAIN-20230204205328-20230204235328-00846.warc.gz"}
|
https://bison.inl.gov/Documentation/syntax/Kernels/index.aspx
|
# Kernels System
A "Kernel" is a piece of physics. It can represent one or more operators or terms in the weak form of a partial differential equation. With all terms on the left-hand-side, their sum is referred to as the "residual". The residual is evaluated at several integration quadrature points over the problem domain. To implement your own physics in MOOSE, you create your own kernel by subclassing the MOOSE Kernel class.
In a Kernel subclass the computeQpResidual() function must be overridden. This is where you implement your PDE weak form terms. The following member functions can optionally be overridden:
• computeQpJacobian()
• computeQpOffDiagJacobian()
These two functions provide extra information that can help the numerical solver(s) converge faster and better. Inside your Kernel class, you have access to several member variables for computing the residual and Jacobian values in the above mentioned functions:
• _i, _j: indices for the current test and trial shape functions respectively.
• _qp: current quadrature point index.
• _u, _grad_u: value and gradient of the variable this Kernel operates on; indexed by _qp (i.e. _u[_qp]).
• _test, _grad_test: value () and gradient () of the test functions at the q-points; indexed by _i and then _qp (i.e., _test[_i][_qp]).
• _phi, _grad_phi: value () and gradient () of the trial functions at the q-points; indexed by _j and then _qp (i.e., _phi[_j][_qp]).
• _q_point: XYZ coordinates of the current quadrature point.
• _current_elem: pointer to the current element being operated on.
## Custom Kernel Creation
To create a custom kernel, you can follow the pattern of the Diffusion kernel implemented and included in the MOOSE framework. Additionally, Example 2 provides a step-by-step overview of creating your own custom kernel.
The strong-form of the diffusion equations is defined on a 3-D domain as: find such that
(1) where is defined as the boundary on which the value of is fixed to a known constant , is defined as the boundary on which the flux across the boundary is fixed to a known constant , and $\hat{n} is the boundary outward normal. The weak form is generated by multiplying by a test function () and integrating over the domain (using inner-product notation): (-\nabla\cdot\nabla u_h, \psi_i) - (f, \psi_i) = 0\quad \forall\,\psi_i and then integrating by parts which gives the weak form: (2) where is known as the trial function that defines the finite element discretization, , with being the basis functions. The Jacobian, which is the derivative of Eq. 2 with respect to , is defined as: (3) The diffusion kernel header and implementation files are: // This file is part of the MOOSE framework // https://www.mooseframework.org // // All rights reserved, see COPYRIGHT for full restrictions // https://github.com/idaholab/moose/blob/master/COPYRIGHT // // Licensed under LGPL 2.1, please see LICENSE for details // https://www.gnu.org/licenses/lgpl-2.1.aspx #ifndef DIFFUSION_H #define DIFFUSION_H #include "Kernel.h" class Diffusion; template <> InputParameters validParams<Diffusion>(); /** * This kernel implements the Laplacian operator: *$\nabla u \cdot \nabla \phi_i$*/ class Diffusion : public Kernel { public: Diffusion(const InputParameters & parameters); protected: virtual Real computeQpResidual() override; virtual Real computeQpJacobian() override; }; #endif /* DIFFUSION_H */ (moose/framework/include/kernels/Diffusion.h) // This file is part of the MOOSE framework // https://www.mooseframework.org // // All rights reserved, see COPYRIGHT for full restrictions // https://github.com/idaholab/moose/blob/master/COPYRIGHT // // Licensed under LGPL 2.1, please see LICENSE for details // https://www.gnu.org/licenses/lgpl-2.1.aspx #include "Diffusion.h" registerMooseObject("MooseApp", Diffusion); template <> InputParameters validParams<Diffusion>() { InputParameters params = validParams<Kernel>(); params.addClassDescription("The Laplacian operator ($-\\nabla \\cdot \\nabla u$), with the weak " "form of$(\\nabla \\phi_i, \\nabla u_h)$."); return params; } Diffusion::Diffusion(const InputParameters & parameters) : Kernel(parameters) {} Real Diffusion::computeQpResidual() { return _grad_u[_qp] * _grad_test[_i][_qp]; } Real Diffusion::computeQpJacobian() { return _grad_phi[_j][_qp] * _grad_test[_i][_qp]; } (moose/framework/src/kernels/Diffusion.C) Before a custom physics kernel is available for use, it must be registered in your application. This is done in e.g. src/base/YourApp.C for the YourApp application. // src/base/YourApp.C contents #include "YourKernel.h" ... int YourApp::registerObjects(Factory & factory) { ... registerKernel(YourKernel); ... } ... ## Time Derivative Kernels You can create a time-derivative term/kernel by subclassing TimeKernel instead of Kernel. For example, the residual contribution for a time derivative term is: (4) where is the finite element solution, and (5) because you can interchange the order of differentiation and summation. In the equation above, is the time derivative of the th finite element coefficient of . While the exact form of this derivative depends on the time stepping scheme, without much loss of generality, we can assume the following form for the time derivative: (6) for some constants , which depend on and the timestepping method. The derivative of equation Eq. 5 with respect to is then: (7) So that the Jacobian term for equation Eq. 5 is (8) where is what we call du_dot_du in MOOSE. Therefore the computeQpResidual() function for our time-derivative term kernel looks like: text cpp return _test[_i][_qp] * _u_dot[_qp]; And the corresponding computeQpJacobian() is: return _test[_i][_qp] * _phi[_j][_qp] * _du_dot_du[_qp]; ## Further Kernel Documentation Several specialized kernel types exist in MOOSE each with useful functionality. Details for each are in the sections below. • AnisoHeatConduction • ConsistentHeatCapacityTimeDerivativeTime derivative term of the heat equation with the heat capacity as an argument. • ConsistentSpecificHeatTimeDerivativeTime derivative term with of the heat equation with the specific heat capacity and density as arguments. • HeatCapacityConductionTimeDerivativeTime derivative term of the heat equation with the heat capacity as an argument. • HeatConductionComputes residual/Jacobian contribution for term. • HeatConductionTimeDerivativeTime derivative term of the heat equation for quasi-constant specific heat and the density . • HeatSourceDemonstrates the multiple ways that scalar values can be introduced into kernels, e.g. (controllable) constants, functions, and postprocessors. Implements the weak form . • HomogenizedHeatConduction • JouleHeatingSourceDemonstrates the multiple ways that scalar values can be introduced into kernels, e.g. (controllable) constants, functions, and postprocessors. Implements the weak form . • SpecificHeatConductionTimeDerivativeTime derivative term of the heat equation with the specific heat and the density as arguments. • CosseratStressDivergenceTensorsStress divergence kernel for the Cartesian coordinate system • DynamicStressDivergenceTensorsResidual due to stress related Rayleigh damping and HHT time integration terms • GeneralizedPlaneStrainOffDiagGeneralized Plane Strain kernel to provide contribution of the out-of-plane strain to other kernels • GravityApply gravity. Value is in units of acceleration. • InertialForceCalculates the residual for the interial force () and the contribution of mass dependent Rayleigh damping and HHT time integration scheme ($\eta \cdot M \cdot ((1+\alpha)velq2-\alpha \cdot vel-old) )
• InertialForceBeamCalculates the residual for the interial force/moment and the contribution of mass dependent Rayleigh damping and HHT time integration scheme.
• InertialTorqueKernel for interial torque: density * displacement x acceleration
• MomentBalancing
• OutOfPlanePressureApply pressure in the out-of-plane direction in 2D plane stress or generalized plane strain models
• PhaseFieldFractureMechanicsOffDiagStress divergence kernel for phase-field fracture: Computes off diagonal damage dependent Jacobian components. To be used with StressDivergenceTensors or DynamicStressDivergenceTensors.
• PlasticHeatEnergyPlastic heat energy density = coeff * stress * plastic_strain_rate
• PoroMechanicsCouplingAdds , where the subscript is the component.
• StressDivergenceBeamQuasi-static and dynamic stress divergence kernel for Beam element
• StressDivergenceRSphericalTensorsCalculate stress divergence for an spherically symmetric 1D problem in polar coordinates.
• StressDivergenceRZTensorsCalculate stress divergence for an axisymmetric problem in cylinderical coordinates.
• StressDivergenceTensorsStress divergence kernel for the Cartesian coordinate system
• StressDivergenceTensorsTrussKernel for truss element
• WeakPlaneStressPlane stress kernel to provide out-of-plane strain contribution
• ACGBPolyGrain-Boundary model concentration dependent residual
• ACGrGrElasticDrivingForceAdds elastic energy contribution to the Allen-Cahn equation
• ACGrGrMultiMulti-phase poly-crystaline Allen-Cahn Kernel
• ACGrGrPolyGrain-Boundary model poly-crystaline interface Allen-Cahn Kernel
• ACInterfaceKobayashi1Anisotropic gradient energy Allen-Cahn Kernel Part 1
• ACInterfaceKobayashi2Anisotropic Gradient energy Allen-Cahn Kernel Part 2
• ACInterfaceStressInterface stress driving force Allen-Cahn Kernel
• ACMultiInterfaceGradient energy Allen-Cahn Kernel with cross terms
• ACSEDGPolyStored Energy contribution to grain growth
• ACSwitchingKernel for Allen-Cahn equation that adds derivatives of switching functions and energies
• AllenCahnAllen-Cahn Kernel that uses a DerivativeMaterial Free Energy
• CHBulkPFCTradCahn-Hilliard kernel for a polynomial phase field crystal free energy.
• CHCpldPFCTradSplit with a variable that holds the Laplacian of a phase field variable.
• CHInterfaceGradient energy Cahn-Hilliard Kernel with a scalar (isotropic) mobility
• CHInterfaceAnisoGradient energy Cahn-Hilliard Kernel with a tensor (anisotropic) mobility
• CHMathSimple demonstration Cahn-Hilliard Kernel using an algebraic double-well potential
• CHPFCRFFCahn-Hilliard residual for the RFF form of the phase field crystal model
• CHSplitChemicalPotentialChemical potential kernel in Split Cahn-Hilliard that solves chemical potential in a weak form
• CHSplitConcentrationConcentration kernel in Split Cahn-Hilliard that solves chemical potential in a weak form
• CHSplitFluxComputes flux as nodal variable
• CahnHilliardCahn-Hilliard Kernel that uses a DerivativeMaterial Free Energy and a scalar (isotropic) mobility
• CahnHilliardAnisoCahn-Hilliard Kernel that uses a DerivativeMaterial Free Energy and a tensor (anisotropic) mobility
• CoefCoupledTimeDerivativeScaled time derivative Kernel that acts on a coupled variable
• CoefReactionImplements the residual term (p*u, test)
• ConservedLangevinNoiseSource term for noise from a ConservedNoise userobject
• CoupledAllenCahnCoupled Allen-Cahn Kernel that uses a DerivativeMaterial Free Energy
• CoupledMaterialDerivativeKernel that implements the first derivative of a function material property with respect to a coupled variable.
• CoupledSusceptibilityTimeDerivativeA modified coupled time derivative Kernel that multiplies the time derivative of a coupled variable by a generalized susceptibility
• CoupledSwitchingTimeDerivativeCoupled time derivative Kernel that multiplies the time derivative by \$\frac{dh_\alpha}{d\eta_i} F_\alpha + \frac{dh_\beta}{d\eta_i} F_\beta + \dots)
• GradientComponentSet the kernel variable to a specified component of the gradient of a coupled variable.
• HHPFCRFFReaction type kernel for the RFF phase fit crystal model
• KKSACBulkCKKS model kernel (part 2 of 2) for the Bulk Allen-Cahn. This includes all terms dependent on chemical potential.
• KKSACBulkFKKS model kernel (part 1 of 2) for the Bulk Allen-Cahn. This includes all terms NOT dependent on chemical potential.
• KKSCHBulkKKS model kernel for the Bulk Cahn-Hilliard term. This operates on the concentration 'c' as the non-linear variable
• KKSMultiACBulkCMulti-phase KKS model kernel (part 2 of 2) for the Bulk Allen-Cahn. This includes all terms dependent on chemical potential.
• KKSMultiACBulkFKKS model kernel (part 1 of 2) for the Bulk Allen-Cahn. This includes all terms NOT dependent on chemical potential.
• KKSMultiPhaseConcentrationKKS multi-phase model kernel to enforce . The non-linear variable of this kernel is , the final phase concentration in the list.
• KKSPhaseChemicalPotentialKKS model kernel to enforce the pointwise equality of phase chemical potentials dFa/dca = dFb/dcb. The non-linear variable of this kernel is ca.
• KKSPhaseConcentrationKKS model kernel to enforce the decomposition of concentration into phase concentration (1-h(eta))ca + h(eta)cb - c = 0. The non-linear variable of this kernel is cb.
• KKSSplitCHCResKKS model kernel for the split Bulk Cahn-Hilliard term. This operates on the chemical potential 'c' as the non-linear variable
• LangevinNoiseSource term for non-conserved Langevin noise
• LaplacianSplitSplit with a variable that holds the Laplacian of a phase field variable.
• MaskedBodyForceKernel that defines a body force modified by a material mask
• MatAnisoDiffusionDiffusion equation Kernel that takes an anisotropic Diffusivity from a material property
• MatDiffusionDiffusion equation Kernel that takes an isotropic Diffusivity from a material property
• MatReactionKernel to add -L*v, where L=reaction rate, v=variable
• MultiGrainRigidBodyMotionAdds rigid mody motion to grains
• SimpleACInterfaceGradient energy for Allen-Cahn Kernel with constant Mobility and Interfacial parameter
• SimpleCHInterfaceGradient energy for Cahn-Hilliard equation with constant Mobility and Interfacial parameter
• SimpleCoupledACInterfaceGradient energy for Allen-Cahn Kernel with constant Mobility and Interfacial parameter for a coupled order parameter variable.
• SimpleSplitCHWResGradient energy for split Cahn-Hilliard equation with constant Mobility for a coupled order parameter variable.
• SingleGrainRigidBodyMotionAdds rigid mody motion to a single grain
• SoretDiffusionAdd Soret effect to Split formulation Cahn-Hilliard Kernel
• SplitCHMathSimple demonstration split formulation Cahn-Hilliard Kernel using an algebraic double-well potential
• SplitCHParsedSplit formulation Cahn-Hilliard Kernel that uses a DerivativeMaterial Free Energy
• SplitCHWResSplit formulation Cahn-Hilliard Kernel for the chemical potential variable with a scalar (isotropic) mobility
• SplitCHWResAnisoSplit formulation Cahn-Hilliard Kernel for the chemical potential variable with a tensor (anisotropic) mobility
• SusceptibilityTimeDerivativeA modified time derivative Kernel that multiplies the time derivative of a variable by a generalized susceptibility
• SwitchingFunctionConstraintEtaLagrange multiplier kernel to constrain the sum of all switching functions in a multiphase system. This kernel acts on a non-conserved order parameter eta_i.
• SwitchingFunctionConstraintLagrangeLagrange multiplier kernel to constrain the sum of all switching functions in a multiphase system. This kernel acts on the lagrange multiplier variable.
• SwitchingFunctionPenaltyPenalty kernel to constrain the sum of all switching functions in a multiphase system.
• CoefDiffusionKernel for diffusion with diffusivity = coef + function
• ThermoDiffusionKernel for thermo-diffusion (Soret effect, thermophoresis, etc.)
• ArrheniusDiffusionDiffusion with Arrhenius coefficient
• CompositeHeatConductionCompute thermal conductivity
• ConstituentDiffusion
• ConstitutiveHeatConductionThe Laplacian operator (), with the weak form of .
• ConstitutiveHeatConductionTimeDerivativeTime derivative term of the heat equation for quasi-constant specific heat and the density .
• Decay
• DiffusionLimitedReactionCalculates losses due to diffusion limited reaction
• FissionRateHeatSource
• HZrHSource
• HydrideSourceAdd source (sink) term for precipitation (dissolution) of hydrogen as hydride
• HydrogenDiffusionCalculates the diffusion of hydrogen in solid solution due to Fick's law and the Soret effect
• HydrogenPrecipitationCalculates the precipitation of hydrogen in solid solution from McMinn's TSSp equilibrium and the dissolution hydrides to solid solution hydrogen from Marino's kinetics
• HydrogenSourceAdd source (sink) term for dissolved hydrogen from hydride dissolution (precipitation)
• HydrogenTimeDerivativeTime derivative for species where the volume fraction of the phase is time-dependent.
• IsotropicDiffusionIsotropic diffusion that uses arbitrary diffusivity
• MOXActinideRedistributionMOX kernel used to simulate actinide redistribution.
• MOXActinideRedistributionEnhancementMOX kernel used to simulate actinide redistribution enhanced by porosity.
• MOXOxygenDiffusionMOX oxygen diffusion kernel.
• MOXPoreContinuityMOX kernel used to simulate pore migration.
• MOXPoreDiffusionMOX porosity diffusion kernel used with kernel MOXPoreContinuity.
• NeutronHeatSourceCompute heat generation due to fission.
• OxideEnergyDepositionComputes the amount of energy released from the zirconium oxide reaction and applies it to the cladding.
• OxygenDiffusion
• ZirconiumDiffusionCalculates the amount of zirconium that is transported across the mesh
• AnisotropicDiffusionAnisotropic diffusion kernel with weak form given by .
• BodyForceDemonstrates the multiple ways that scalar values can be introduced into kernels, e.g. (controllable) constants, functions, and postprocessors. Implements the weak form .
• CoefTimeDerivativeThe time derivative operator with the weak form of .
• ConservativeAdvectionConservative form of which in its weak form is given by: .
• CoupledForceImplements a source term proportional to the value of a coupled variable. Weak form: .
• CoupledTimeDerivativeTime derivative Kernel that acts on a coupled variable. Weak form: .
• DiffusionThe Laplacian operator (), with the weak form of .
• MassEigenKernelAn eigenkernel with weak form where is the eigenvalue.
• MassLumpedTimeDerivativeLumped formulation of the time derivative . Its corresponding weak form is where denotes the time derivative of the solution coefficient associated with node .
• MaterialDerivativeRankFourTestKernelClass used for testing derivatives of a rank four tensor material property.
• MaterialDerivativeRankTwoTestKernelClass used for testing derivatives of a rank two tensor material property.
• MaterialDerivativeTestKernelClass used for testing derivatives of a scalar material property.
• NullKernelKernel that sets a zero residual.
• ReactionImplements a simple consuming reaction term with weak form .
• TimeDerivativeThe time derivative operator with the weak form of .
• UserForcingFunctionDemonstrates the multiple ways that scalar values can be introduced into kernels, e.g. (controllable) constants, functions, and postprocessors. Implements the weak form .
• VectorBodyForceDemonstrates the multiple ways that scalar values can be introduced into kernels, e.g. (controllable) constants, functions, and postprocessors. Implements the weak form .
• VectorDiffusionThe Laplacian operator (), with the weak form of .
• CrackTipEnrichmentStressDivergenceTensorsEnrich stress divergence kernel for small-strain simulations
| 2020-11-28T02:48:28 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.893325924873352, "perplexity": 7501.236866143754}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141194982.45/warc/CC-MAIN-20201128011115-20201128041115-00043.warc.gz"}
|
https://par.nsf.gov/biblio/10319751-self-similarity-particle-accumulation-advancing-meniscus
|
Self-similarity in particle accumulation on the advancing meniscus
When a mixture of viscous oil and non-colloidal particles displaces air between two parallel plates, the shear-induced migration of particles leads to the gradual accumulation of particles on the advancing oil–air interface. This particle accumulation results in the fingering of an otherwise stable fluid–fluid interface. While previous works have focused on the resultant instability, one unexplored yet striking feature of the experiments is the self-similarity in the concentration profile of the accumulating particles. In this paper, we rationalise this self-similar behaviour by deriving a depth-averaged particle transport equation based on the suspension balance model, following the theoretical framework of Ramachandran ( J. Fluid Mech. , vol. 734, 2013, pp. 219–252). The solutions to the particle transport equation are shown to be self-similar with slight deviations, and in excellent agreement with experimental observations. Our results demonstrate that the combination of the shear-induced migration, the advancing fluid–fluid interface and Taylor dispersion yield the self-similar and gradual accumulation of particles.
Authors:
; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10319751
Journal Name:
Journal of Fluid Mechanics
Volume:
925
ISSN:
0022-1120
1. This study explores thermal convection in suspensions of neutrally buoyant, non-colloidal suspensions confined between horizontal plates. A constitutive diffusion equation is used to model the dynamics of the particles suspended in a viscous fluid and it is coupled with the flow equations. We employ a simple model that was proposed by Metzger, Rahli & Yin ( J. Fluid Mech. , vol. 724, 2013, pp. 527–552) for the effective thermal diffusivity of suspensions. This model considers the effect of shear-induced diffusion and gives the thermal diffusivity increasing linearly with the thermal Péclet number ( Pe ) and the particle volume fraction ( ϕ ). Both linear stability analysis and numerical simulation based on the mathematical models are performed for various bulk particle volume fractions $({\phi _b})$ ranging from 0 to 0.3. The critical Rayleigh number $(R{a_c})$ grows gradually by increasing ${\phi _b}$ from the critical value $(R{a_c} = 1708)$ for a pure Newtonian fluid, while the critical wavenumber $({k_c})$ remains constant at 3.12. The transition from the conduction state of suspensions is subcritical, whereas it is supercritical for the convection in a pure Newtonian fluid $({\phi _b} = 0)$ . The heat transfer in moderately dense suspensions $({\phi _b} = 0.2\text{--}0.3)$more »
2. The margination and adhesion of micro-particles (MPs) have been extensively investigated separately, due to their important applications in the biomedical field. However, the cascade process from margination to adhesion should play an important role in the transport of MPs in blood flow. To the best of our knowledge, this has not been explored in the past. Here we numerically study the margination behaviour of elastic MPs to blood vessel walls under the interplay of their deformability and adhesion to the vessel wall. We use the lattice Boltzmann method and molecular dynamics to solve the fluid dynamics and particle dynamics (including red blood cells (RBCs) and elastic MPs) in blood flow, respectively. Additionally, a stochastic ligand–receptor binding model is employed to capture the adhesion behaviours of elastic MPs on the vessel wall. Margination probability is used to quantify the localization of elastic MPs at the wall. Two dimensionless numbers are considered to govern the whole process: the capillary number $Ca$ , denoting the ratio of viscous force of fluid flow to elastic interfacial force of MP, and the adhesion number $Ad$ , representing the ratio of adhesion strength to viscous force of fluid flow. We systematically vary them numerically and amore »
3. Understanding the orientation dynamics of anisotropic colloidal particles is important for suspension rheology and particle self-assembly. However, even for the simplest case of dilute suspensions in shear flow, the orientation dynamics of non-spherical Brownian particles are poorly understood. Here we analytically calculate the time-dependent orientation distributions for non-spherical axisymmetric particles confined to rotate in the flow–gradient plane, in the limit of small but non-zero Brownian diffusivity. For continuous shear, despite the complicated dynamics arising from the particle rotations, we find a coordinate change that maps the orientation dynamics to a diffusion equation with a remarkably simple ratio of the enhanced rotary diffusivity to the zero shear diffusion: $D_{eff}^{r}/D_{0}^{r}=(3/8)(p-1/p)^{2}+1$ , where $p$ is the particle aspect ratio. For oscillatory shear, the enhanced diffusion becomes orientation dependent and drastically alters the long-time orientation distributions. We describe a general method for solving the time-dependent oscillatory shear distributions and finding the effective diffusion constant. As an illustration, we use this method to solve for the diffusion and distributions in the case of triangle-wave oscillatory shear and find that they depend strongly on the strain amplitude and particle aspect ratio. These results provide new insight into the time-dependent rheology of suspensions of anisotropic particles. Formore »
| 2023-03-28T14:09:17 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6541851162910461, "perplexity": 853.0368726809106}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296948867.32/warc/CC-MAIN-20230328135732-20230328165732-00610.warc.gz"}
|
https://www.zbmath.org/authors/?q=ai%3Asjostrand.johannes
|
## Sjöstrand, Johannes
Compute Distance To:
Author ID: sjostrand.johannes Published as: Sjöstrand, Johannes; Sjöstrand, J.; Sjoestrand, Johannes; Sjoestrand, J.; Sjostrand, J. Homepage: http://sjostrand.perso.math.cnrs.fr/ External Links: MGP · Wikidata · GND · IdRef · theses.fr
Documents Indexed: 219 Publications since 1970, including 3 Books 4 Contributions as Editor · 2 Further Contributions Co-Authors: 74 Co-Authors with 142 Joint Publications 1,581 Co-Co-Authors
all top 5
### Co-Authors
82 single-authored 29 Helffer, Bernard 18 Hitrik, Michael 17 Zworski, Maciej 7 Melin, Anders 5 Hérau, Frédéric 5 Vögel, Martin 4 Baouendi, Mohammed Salah 4 Menikoff, A. 4 Uhlmann, Gunther Alberto 3 Berman, Robert J. 3 Caliceti, Emanuela 3 Demuth, Michael 3 Gérard, Christian 3 Graffi, Sandro 3 Grigis, Alain 3 Kenig, Carlos Eduardo 3 Lascar, Bernard 3 Melrose, Richard Burt 3 Ramond, Thierry 3 Schrohe, Elmar 3 Schulze, Bert-Wolfgang 3 Vũ Ngọc, San 2 Berndtsson, Bo 2 Boussekkine, Naima 2 Boutet de Monvel, Louis 2 Coburn, Lewis A. 2 Dimassi, Mouez 2 Dos Santos Ferreira, David 2 Duistermaat, Johannes Jisse 2 Faure, Frédéric 2 Guillemin, Victor W. 2 Iantchenko, Alexai 2 Kashiwara, Masaki 2 Kawai, Takahiro 2 Martinez, André 2 Mecherout, Nawal 2 Nonnenmacher, Stéphane 2 Presilla, Carlo 2 Wang, Wei-Min 2 Zerzeri, Maher 1 Andersson, Mats 1 Atiyah, Michael Francis 1 Avetisyan, Zhirayr G. 1 Bach, Volker 1 Benbernou, Amina Lahmar 1 Bony, Jean-François 1 Bordeaux Montrieux, William 1 Cushman, Richard H. 1 Dencker, Nils 1 Hager, Mildred 1 Hall, Michael A. 1 Hanges, Nicholas William 1 Heckman, Gert 1 Jecko, Thierry 1 Jona-Lasinio, Giovanni 1 Kahane, Jean-Pierre 1 Klein, Christian 1 Kolk, Johan A. C. 1 Lascar, Richard 1 Lévy-Leblond, Jean-Marc 1 Nirenberg, Louis 1 Pelayo, Alvaro 1 Ramm, Alexander G. 1 Rauch, Jeffrey B. 1 Rouby, Ophélie 1 Roy, Nicolas David 1 Schapira, Pierre 1 Shubin, Mikhail Aleksandrovich 1 Sjamaar, Reyer 1 Stoilov, Nikola M. 1 Stolk, Christiaan C. 1 Van den Ban, Erik Peter 1 Vassiliev, Dmitri G. 1 Viola, Joe 1 Vodev, Georgi 1 Weinstein, Alan David 1 White, Francis 1 Zelditch, Steve
all top 5
### Serials
12 Communications in Partial Differential Equations 10 Séminaire Équations aux Dérivées Partielles 7 Communications in Mathematical Physics 7 Mémoires de la Société Mathématique de France. Nouvelle Série 6 Arkiv för Matematik 5 Annales de l’Institut Fourier 5 Duke Mathematical Journal 5 Annales de l’Institut Henri Poincaré. Physique Théorique 5 Mathematical Research Letters 4 Mathematische Annalen 4 Mathematische Nachrichten 4 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 4 Annales Henri Poincaré 4 Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences, Série A 3 Communications on Pure and Applied Mathematics 3 Journal d’Analyse Mathématique 3 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 3 Journal of Functional Analysis 3 Annals of Mathematics. Second Series 3 Mathematical Topics 3 Analysis & PDE 2 Helvetica Physica Acta 2 Acta Mathematica 2 American Journal of Mathematics 2 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 2 Canadian Journal of Mathematics 2 Asymptotic Analysis 2 IMRN. International Mathematics Research Notices 2 Comptes Rendus de l’Académie des Sciences. Série I 2 St. Petersburg Mathematical Journal 2 London Mathematical Society Lecture Note Series 2 Journal of Physics A: Mathematical and Theoretical 2 Journal of Spectral Theory 1 Journal of Mathematical Physics 1 Journal of Statistical Physics 1 Letters in Mathematical Physics 1 Hokkaido Mathematical Journal 1 Indiana University Mathematics Journal 1 Integral Equations and Operator Theory 1 Inventiones Mathematicae 1 Mathematische Zeitschrift 1 Publications of the Research Institute for Mathematical Sciences, Kyoto University 1 Cahiers Mathématiques 1 Journal of the American Mathematical Society 1 Annals of Physics 1 Journal de Mathématiques Pures et Appliquées. Neuvième Série 1 Journal of Physics A: Mathematical and General 1 Notices of the American Mathematical Society 1 Indagationes Mathematicae. New Series 1 Methods and Applications of Analysis 1 Serdica Mathematical Journal 1 Journal of the European Mathematical Society (JEMS) 1 Journal of the Institute of Mathematics of Jussieu 1 RIMS Kôkyûroku Bessatsu 1 Pseudo-Differential Operators. Theory and Applications 1 The Open Mathematics Journal 1 Journal of Pseudo-Differential Operators and Applications 1 Contemporary Mathematicians 1 Pure and Applied Analysis
all top 5
### Fields
195 Partial differential equations (35-XX) 63 Operator theory (47-XX) 62 Quantum theory (81-XX) 45 Global analysis, analysis on manifolds (58-XX) 11 Dynamical systems and ergodic theory (37-XX) 9 Several complex variables and analytic spaces (32-XX) 9 Ordinary differential equations (34-XX) 9 Statistical mechanics, structure of matter (82-XX) 8 Differential geometry (53-XX) 6 Linear and multilinear algebra; matrix theory (15-XX) 5 Functions of a complex variable (30-XX) 4 Functional analysis (46-XX) 4 Probability theory and stochastic processes (60-XX) 4 Numerical analysis (65-XX) 4 Optics, electromagnetic theory (78-XX) 3 General and overarching topics; collections (00-XX) 3 Potential theory (31-XX) 3 Harmonic analysis on Euclidean spaces (42-XX) 3 Integral transforms, operational calculus (44-XX) 2 History and biography (01-XX) 2 Mechanics of particles and systems (70-XX) 1 Measure and integration (28-XX) 1 Calculus of variations and optimal control; optimization (49-XX) 1 Algebraic topology (55-XX) 1 Classical thermodynamics, heat transfer (80-XX) 1 Biology and other natural sciences (92-XX)
### Citations contained in zbMATH Open
185 Publications have been cited 3,666 times in 2,059 Documents Cited by Year
Spectral asymptotics in the semi-classical limit. Zbl 0926.35002
Dimassi, Mouez; Sjöstrand, Johannes
1999
Multiple wells in the semi-classical limit. I. Zbl 0546.35053
Helffer, B.; Sjöstrand, J.
1984
Sur la singularite des noyaux de Bergman et de Szegö. Zbl 0344.32010
Boutet de Monvel, L.; Sjöstrand, J.
1976
The Calderón problem with partial data. Zbl 1127.35079
Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2007
Singularities of boundary value problems. I. Zbl 0368.35020
Melrose, R. B.; Sjöstrand, J.
1978
Singularites analytiques microlocales. Zbl 0524.35007
Sjoestrand, Johannes
1982
An algebra of pseudodifferential operators. Zbl 0840.35130
Sjöstrand, Johannes
1994
Complex scaling and the distribution of scattering poles. Zbl 0752.35046
Sjöstrand, Johannes; Zworski, Maciej
1991
Equation de Schrödinger avec champ magnétique et équation de Harper. (The Schrödinger equation with magnetic field and the Harper equation). Zbl 0699.35189
Helffer, B.; Sjöstrand, J.
1989
Parametrices for pseudodifferential operators with multiple characteristics. Zbl 0317.35076
Sjöstrand, Johannes
1974
Résonances en limite semi-classique. (Resonances in semi-classical limit). Zbl 0631.35075
Helffer, B.; Sjöstrand, J.
1986
Microlocal analysis for differential operators. An introduction. Zbl 0804.35001
Grigis, Alain; Sjöstrand, Johannes
1994
Singularities of boundary value problems. II. Zbl 0546.35083
Melrose, R. B.; Sjöstrand, J.
1982
Determining a magnetic Schrödinger operator from partial Cauchy data. Zbl 1148.35096
dos Santos Ferreira, David; Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2007
Puits multiples en mécanique semi-classique. IV: Étude du complexe de Witten. (Multiple wells in semi-classical limit. IV: Investigation of the Witten complex). Zbl 0597.35024
Helffer, B.; Sjöstrand, J.
1985
Analyse semi-classique pour l’équation de Harper (avec application à l’équation de Schrödinger avec champ magnétique). (Semiclassical analysis for the Harper equation (with application to the magnetic Schrödinger equation)). Zbl 0714.34130
Helffer, B.; Sjöstrand, J.
1988
A direct approach to Bergman kernel asymptotics for positive line bundles. Zbl 1161.32001
Berman, Robert; Berndtsson, Bo; Sjöstrand, Johannes
2008
Puits multiples en limite semi-classique. II: Interaction moléculaire. Symétries. Perturbation. (Multiple wells in the semi-classical limit. II: Molecular interaction. Symmetry. Perturbation). Zbl 0595.35031
Helffer, B.; Sjöstrand, J.
1985
Semi-classical analysis for Harper’s equation. III: Cantor structure of the spectrum. Zbl 0725.34099
Helffer, B.; Sjöstrand, J.
1989
On the correlation for Kac-like models in the convex case. Zbl 0946.35508
Helffer, Bernard; Sjöstrand, Johannes
1994
Geometric bounds on the density of resonances for semiclassical problems. Zbl 0702.35188
Sjöstrand, Johannes
1990
Pseudospectra of semiclassical (pseudo-) differential operators. Zbl 1054.35035
Dencker, Nils; Sjöstrand, Johannes; Zworski, Maciej
2004
Fourier integral operators with complex-valued phase functions. Zbl 0306.42007
Melin, Anders; Sjöstrand, Johannes
1975
Semiclassical resonances generated by a closed trajectory of hyperbolic type. Zbl 0637.35027
Gérard, C.; Sjöstrand, J.
1987
Upper bound on the density of Ruelle resonances for Anosov flows. Zbl 1260.37016
Faure, Frédéric; Sjöstrand, Johannes
2011
Wiener type algebras of pseudodifferential operators. Zbl 0880.35145
Sjöstrand, J.
1995
On the eigenvalues of a class of hypoelliptic operators. Zbl 0375.35014
Menikoff, A.; Sjöstrand, J.
1978
Fractal upper bounds on the density of semiclassical resonances. Zbl 1201.35189
Sjöstrand, Johannes; Zworski, Maciej
2007
An inverse problem for the wave equation. Zbl 0697.35164
Ramm, A. G.; Sjöstrand, J.
1991
Analytic wavefront sets and operators with multiple characteristics. Zbl 0531.35022
Sjöstrand, Johannes
1983
Elementary linear algebra for advanced spectral problems. Zbl 1140.15009
Sjöstrand, Johannes; Zworski, Maciej
2007
Fourier integral operators with complex phase functions and parametrix for an interior boundary value problem. Zbl 0364.35049
Melin, Anders; Sjöstrand, Johannes
1976
Multiple wells in the semi-classical limit. III: Interaction through non- resonant wells. Zbl 0597.35023
Helffer, B.; Sjöstrand, J.
1985
A trace formula and review of some estimates for resonances. Zbl 0877.35090
Sjöstrand, J.
1997
Analyse semi-classique pour l’équation de Harper. II: Comportement semi-classique près d’un rationnel. (Semiclassical analysis for the Harper equation. II. Semiclassical behaviour near a rational number). Zbl 0714.34131
Helffer, B.; Sjöstrand, J.
1990
Front d’onde analytique et sommes de carrés de champs de vecteurs. Zbl 0581.35009
Grigis, A.; Sjöstrand, J.
1985
Resonances for bottles and trace formulae. Zbl 0979.35109
Sjöstrand, Johannes
2001
A mathematical approach to the effective Hamiltonian in perturbed periodic problems. Zbl 0753.35057
Gerard, C.; Martinez, A.; Sjöstrand, J.
1991
On diamagnetism and de Haas-van Alphen effect. Zbl 0715.35070
Helffer, B.; Sjöstrand, J.
1990
Lower bounds on the number of scattering poles. II. Zbl 0823.35137
Sjöstrand, Johannes; Zworski, Maciej
1994
Microlocal analysis for the periodic magnetic Schrödinger equation and related questions. Zbl 0761.35090
Sjöstrand, Johannes
1991
Semi-classical approach for Anosov diffeomorphisms and Ruelle resonances. Zbl 1177.37032
Faure, Frédéric; Roy, Nicolas; Sjöstrand, Johannes
2008
Operators of principal type with interior boundary conditions. Zbl 0253.35076
Sjöstrand, Johannes
1973
Lower bounds on the number of scattering poles. Zbl 0784.35070
Sjöstrand, Johannes; Zworski, Maciej
1993
Semi-excited states in nondegenerate potential wells. Zbl 0782.35050
Sjöstrand, Johannes
1992
Birkhoff normal forms in semi-classical inverse problems. Zbl 1258.35208
Iantchenko, Alexai; Sjöstrand, Johannes; Zworski, Maciej
2002
Quantum monodromy and semi-classical trace formulæ. Zbl 1038.58033
Sjöstrand, Johannes; Zworski, Maciej
2002
Effet tunnel pour l’équation de Schrödinger avec champ magnétique. (Tunnel effect for the Schrödinger equation with a magnetic field). Zbl 0699.35205
Helffer, B.; Sjöstrand, J.
1987
Asymptotic distribution of eigenfrequencies for damped wave equations. Zbl 0984.35121
Sjöstrand, Johannes
2000
Propagation of analytic singularities for second order Dirichlet problems. Zbl 0458.35026
Sjöstrand, Johannes
1980
On Schrödinger equations with concentrated nonlinearities. Zbl 0820.34050
Jona-Lasinio, Giovanni; Presilla, Carlo; Sjöstrand, Johannes
1995
Eigenvalue asymptotics for randomly perturbed non-selfadjoint operators. Zbl 1151.35063
Hager, Mildred; Sjöstrand, Johannes
2008
Asymptotic distribution of resonances for convex obstacles. Zbl 0989.35099
Sjöstrand, Johannes; Zworski, Maciej
1999
Semiclassical analysis for the Kramers-Fokker-Planck equation. Zbl 1083.35149
Hérau, Frédéric; Sjöstrand, Johannes; Stolk, Christiaan C.
2005
Correlation asymptotics and Witten Laplacians. Zbl 0877.35084
Sjöstrand, J.
1996
The inverse spectral problem. Zbl 1061.58029
Zelditch, Steve
2004
On a class of linear partial differential equations whose formal solutions always converge. Zbl 0411.35003
Kashiwara, Masaki; Kawai, Takahiro; Sjöstrand, Johannes
1979
A global construction for pseudo-differential operators with non- involutive characteristics. Zbl 0282.35071
Duistermaat, J. J.; Sjöstrand, J.
1973
Eigenvalue distribution for non-self-adjoint operators with small multiplicative random perturbations. Zbl 1194.47058
Sjöstrand, Johannes
2009
Tunnel effect and symmetries for Kramers-Fokker-Planck type operators. Zbl 1223.35246
Hérau, Frédéric; Hitrik, Michael; Sjöstrand, Johannes
2011
Hitrik, Michael; Sjöstrand, Johannes
2004
Spectra of $$PT$$-symmetric operators and perturbation theory. Zbl 1065.81054
Caliceti, Emanuela; Graffi, Sandro; Sjöstrand, Johannes
2005
Tunnel effect for Kramers-Fokker-Planck type operators. Zbl 1141.82011
Hérau, Frédéric; Hitrik, Michael; Sjöstrand, Johannes
2008
Diophantine tori and spectral asymptotics for nonselfadjoint operators. Zbl 1172.35085
Hitrik, Michael; Sjöstrand, Johannes; San Vũ Ngọc
2007
Propagation of analyticity for a class of non-micro-characteristic operators. Zbl 0537.35007
Hanges, Nicholas; Sjöstrand, Johannes
1982
Density of resonances for strictly convex analytic obstacles. With an appendix by M. Zworski. Zbl 0863.35072
Sjöstrand, Johannes
1996
The complex scaling method for scattering by strictly convex obstacles. Zbl 0839.35095
Sjöstrand, Johannes; Zworski, Maciej
1995
Trace formula for resonances in small domains. Zbl 1068.47055
Bony, Jean-François; Sjöstrand, Johannes
2001
Potential wells in high dimensions. I. Zbl 0770.35050
Sjöstrand, Johannes
1993
Birkhoff normal forms for Fourier integral operators. II. Zbl 1011.35144
Iantchenko, A.; Sjöstrand, J.
2002
Semiclassical resonances generated by non-degenerate critical points. Zbl 0627.35074
Sjöstrand, Johannes
1987
Asymptotics of the number of Rayleigh resonances. Zbl 0890.35098
Sjöstrand, Johannes; Vodev, Georgi
1997
Function spaces associated to global $$I$$-Lagrangian manifolds. Zbl 0889.46027
Sjöstrand, Johannes
1996
Correlation asymptotics of classical lattice spin systems with nonconvex Hamilton function at low temperature. Zbl 1021.82002
Bach, V.; Jecko, T.; Sjöstrand, J.
2000
Adiabatic projections from the pseudodifferential point of view. (Projecteurs adiabatiques du point de vue pseudodifférentiel.) Zbl 0783.35087
Sjöstrand, Johannes
1993
Analytic singularities and microhyperbolic boundary value problems. Zbl 0459.35007
Sjöstrand, Johannes
1980
Weyl law for semi-classical resonances with randomly perturbed potentials. Zbl 1304.35010
Sjöstrand, Johannes
2014
On the linearized local Calderón problem. Zbl 1198.31003
Dos Santos Ferreira, David; Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2009
Determinants of pseudodifferential operators and complex deformations of phase space. Zbl 1082.35176
Melin, A.; Sjöstrand, J.
2002
Propagation of singularities for operators with multiple involutive characteristics. Zbl 0313.58021
Sjöstrand, Johannes
1976
Puits multiples en mécanique semi-classique. V: Étude des minipuits. (Multiple wells in semi-classical mechanics. V: Study of miniwells). Zbl 0628.35024
Helffer, B.; Sjöstrand, J.
1986
Resonances en limite semiclassique et exposants de Lyapunov. (Resonances in semiclassical limit and Lyapunov exponents). Zbl 0698.35118
Gérard, C.; Sjöstrand, J.
1988
Note on a paper of F. Treves concerning Mizohata type operators. Zbl 0471.35076
Sjöstrand, J.
1980
Resonances associated to a closed hyperbolic trajectory in dimension 2. Zbl 1060.35096
Sjöstrand, Johannes
2003
Eigenvalue distribution for non-self-adjoint operators on compact manifolds with small multiplicative random perturbations. Zbl 1206.35267
Sjöstrand, Johannes
2010
Resolvent estimates for non-selfadjoint operators via semigroups. Zbl 1198.47068
Sjöstrand, Johannes
2010
Régularité analytique pour des opérateurs elliptiques singuliers en un point. Zbl 0334.35021
Baouendi, M. S.; Sjöstrand, J.
1976
Transport properties in resonant tunneling heterostructures. Zbl 0868.35112
Presilla, Carlo; Sjöstrand, Johannes
1996
Semiclassical expansions of the thermodynamic limit for a Schrödinger equation. I: The one well case. Zbl 0788.35109
Helffer, B.; Sjöstrand, J.
1992
Potential wells in high dimensions. II: More about the one well case. Zbl 0770.35051
Sjöstrand, Johannes
1993
On the eigenvalues of a class of hypoelliptic operators. IV. Zbl 0417.47024
Sjöstrand, Johannes
1980
The eigenvalues of hypoelliptic operators. III: The non-semibounded case. Zbl 0436.35065
Menikoff, A.; Sjöstrand, J.
1979
Distribution of scattering poles near the real axis. Zbl 0766.35031
Sjöstrand, Johannes; Zworski, Maciej
1992
Puits multiples en mécanique semi-classique. VI: Cas des puits sous- variétés. (Multiple wells in semi-classical mechanics. VI: The case of submanifold wells). Zbl 0648.35027
Helffer, B.; Sjöstrand, J.
1987
Functional calculus for non-commuting operators with real spectra via an iterated Cauchy formula. Zbl 1070.47009
2004
Quadratic $$\mathcal{PT}$$-symmetric operators with real spectrum and similarity to self-adjoint operators. Zbl 1263.81190
Caliceti, Emanuela; Graffi, Sandro; Hitrik, Michael; Sjöstrand, Johannes
2012
Resolvent estimates for elliptic quadratic differential operators. Zbl 1295.47045
Hitrik, Michael; Sjöstrand, Johannes; Viola, Joe
2013
$$P{\mathcal T}$$ symmetric non-self-adjoint operators, diagonalizable and non-diagonalizable, with a real discrete spectrum. Zbl 1124.81018
Caliceti, Emanuela; Graffi, Sandro; Sjöstrand, Johannes
2007
From open quantum systems to open quantum maps. Zbl 1223.81127
Nonnenmacher, Stéphane; Sjöstrand, Johannes; Zworski, Maciej
2011
Exponential convergence of the first eigenvalue divided by the dimension, for certain sequences of Schrödinger operator. Zbl 0796.35123
Sjöstrand, Johannes
1992
Toeplitz band matrices with small random perturbations. Zbl 07298855
Sjöstrand, Johannes; Vogel, Martin
2021
General Toeplitz matrices subject to Gaussian perturbations. Zbl 1479.15039
Sjöstrand, Johannes; Vogel, Martin
2021
Weyl symbols and boundedness of Toeplitz operators. Zbl 07356560
Coburn, Lewis; Hitrik, Michael; Sjöstrand, Johannes; White, Francis
2021
Improving semigroup bounds with resolvent estimates. Zbl 07367384
Helffer, B.; Sjöstrand, J.
2021
Analytic Bergman operators in the semiclassical limit. Zbl 1469.32003
Rouby, Ophélie; Sjöstrand, Johannes; Vũ Ngọc San
2020
The second Weyl coefficient for a first order system. Zbl 1445.35270
Avetisyan, Zhirayr; Sjöstrand, Johannes; Vassiliev, Dmitri
2020
Non-self-adjoint differential operators, spectral asymptotics and random perturbations. Zbl 1473.35004
Sjöstrand, Johannes
2019
Positivity, complex FIOs, and Toeplitz operators. Zbl 1429.32047
Coburn, Lewis A.; Hitrik, Michael; Sjöstrand, Johannes
2019
Two minicourses on analytic microlocal analysis. Zbl 1418.32003
Hitrik, Michael; Sjöstrand, Johannes
2018
Rational invariant tori and band edge spectra for non-selfadjoint operators. Zbl 1405.35118
Hitrik, Michael; Sjöstrand, Johannes
2018
Interior eigenvalue density of large bi-diagonal matrices subject to random perturbations. Zbl 06761086
Sjöstrand, Johannes; Vogel, Martin
2017
Interior eigenvalue density of Jordan matrices with random perturbations. Zbl 06994392
Sjöstrand, Johannes; Vogel, Martin
2017
Large bidiagonal matrices and random perturbations. Zbl 1454.47034
Sjöstrand, Johannes; Vogel, Martin
2016
$$\mathcal{PT}$$-symmetry and Schrödinger operators. The double well case. Zbl 1337.35103
Mecherout, Nawal; Boussekkine, Naima; Ramond, Thierry; Sjöstrand, Johannes
2016
Local analytic regularity in the linearized Calderón problem. Zbl 1342.35456
Sjöstrand, Johannes; Uhlmann, Gunther
2016
Spectra for semiclassical operators with periodic bicharacteristics in dimension two. Zbl 1341.58019
Hall, Michael A.; Hitrik, Michael; Sjöstrand, Johannes
2015
Weyl law for semi-classical resonances with randomly perturbed potentials. Zbl 1304.35010
Sjöstrand, Johannes
2014
Fractal Weyl law for open quantum chaotic maps. Zbl 1293.81022
Nonnenmacher, Stéphane; Sjöstrand, Johannes; Zworski, Maciej
2014
Supersymmetric structures for second order differential operators. Zbl 1303.81086
Hérau, F.; Hitrik, M.; Sjöstrand, J.
2014
Resolvent estimates for elliptic quadratic differential operators. Zbl 1295.47045
Hitrik, Michael; Sjöstrand, Johannes; Viola, Joe
2013
Quadratic $$\mathcal{PT}$$-symmetric operators with real spectrum and similarity to self-adjoint operators. Zbl 1263.81190
Caliceti, Emanuela; Graffi, Sandro; Hitrik, Michael; Sjöstrand, Johannes
2012
Diophantine tori and Weyl laws for non-selfadjoint operators in dimension two. Zbl 1256.35039
Hitrik, Michael; Sjöstrand, Johannes
2012
Upper bound on the density of Ruelle resonances for Anosov flows. Zbl 1260.37016
Faure, Frédéric; Sjöstrand, Johannes
2011
Tunnel effect and symmetries for Kramers-Fokker-Planck type operators. Zbl 1223.35246
Hérau, Frédéric; Hitrik, Michael; Sjöstrand, Johannes
2011
From open quantum systems to open quantum maps. Zbl 1223.81127
Nonnenmacher, Stéphane; Sjöstrand, Johannes; Zworski, Maciej
2011
Remembering Johannes J. Duistermaat (1942–2010). Zbl 1225.01067
Atiyah, Michael; Cushman, Richard; Heckman, Gert; van den Ban, Erik; Kolk, Johan; Nirenberg, Louis; Sjamaar, Reyer; Sjöstrand, Johannes
2011
Eigenvalue distributions and Weyl laws for semiclassical non-self-adjoint operators in 2 dimensions. Zbl 1248.35241
Sjöstrand, Johannes
2011
Eigenvalue distribution for non-self-adjoint operators on compact manifolds with small multiplicative random perturbations. Zbl 1206.35267
Sjöstrand, Johannes
2010
Resolvent estimates for non-selfadjoint operators via semigroups. Zbl 1198.47068
Sjöstrand, Johannes
2010
Almost sure Weyl asymptotics for non-self-adjoint elliptic operators on compact manifolds. Zbl 1228.47046
Montrieux, William Bordeaux; Sjöstrand, Johannes
2010
Counting zeros of holomorphic functions of exponential growth. Zbl 1214.30006
Sjöstrand, Johannes
2010
Eigenvalue distribution for non-self-adjoint operators with small multiplicative random perturbations. Zbl 1194.47058
Sjöstrand, Johannes
2009
On the linearized local Calderón problem. Zbl 1198.31003
Dos Santos Ferreira, David; Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2009
Resonances for nonanalytic potentials. Zbl 1203.35033
Martinez, André; Ramond, Thierry; Sjöstrand, Johannes
2009
Some results on nonselfadjoint operators: a survey. Zbl 1189.47009
Sjöstrand, Johannes
2009
A direct approach to Bergman kernel asymptotics for positive line bundles. Zbl 1161.32001
Berman, Robert; Berndtsson, Bo; Sjöstrand, Johannes
2008
Semi-classical approach for Anosov diffeomorphisms and Ruelle resonances. Zbl 1177.37032
Faure, Frédéric; Roy, Nicolas; Sjöstrand, Johannes
2008
Eigenvalue asymptotics for randomly perturbed non-selfadjoint operators. Zbl 1151.35063
Hager, Mildred; Sjöstrand, Johannes
2008
Tunnel effect for Kramers-Fokker-Planck type operators. Zbl 1141.82011
Hérau, Frédéric; Hitrik, Michael; Sjöstrand, Johannes
2008
Tunnel effect for Kramers-Fokker-Planck type operators: return to equilibrium and applications. Zbl 1151.35012
Hérau, Frédéric; Hitrik, Michael; Sjöstrand, Johannes
2008
Pseudodifferential operators and weighted normed symbol spaces. Zbl 1199.35410
Sjöstrand, J.
2008
Non-selfadjoint perturbations of selfadjoint operators in two dimensions IIIa. One branching point. Zbl 1147.31004
Hitrik, Michael; Sjöstrand, Johannes
2008
Rational invariant tori, phase space tunneling, and spectra for non-selfadjointoperators in dimension 2. Zbl 1171.35131
Hitrik, Michael; Sjöstrand, Johannes
2008
The Calderón problem with partial data. Zbl 1127.35079
Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2007
Determining a magnetic Schrödinger operator from partial Cauchy data. Zbl 1148.35096
dos Santos Ferreira, David; Kenig, Carlos E.; Sjöstrand, Johannes; Uhlmann, Gunther
2007
Fractal upper bounds on the density of semiclassical resonances. Zbl 1201.35189
Sjöstrand, Johannes; Zworski, Maciej
2007
Elementary linear algebra for advanced spectral problems. Zbl 1140.15009
Sjöstrand, Johannes; Zworski, Maciej
2007
Diophantine tori and spectral asymptotics for nonselfadjoint operators. Zbl 1172.35085
Hitrik, Michael; Sjöstrand, Johannes; San Vũ Ngọc
2007
$$P{\mathcal T}$$ symmetric non-self-adjoint operators, diagonalizable and non-diagonalizable, with a real discrete spectrum. Zbl 1124.81018
Caliceti, Emanuela; Graffi, Sandro; Sjöstrand, Johannes
2007
Asymptotics for Bergman-Hodge kernels for high powers of complex line bundles. Zbl 1207.32012
Berman, Robert; Sjöstrand, Johannes
2007
Semiclassical analysis for the Kramers-Fokker-Planck equation. Zbl 1083.35149
Hérau, Frédéric; Sjöstrand, Johannes; Stolk, Christiaan C.
2005
Spectra of $$PT$$-symmetric operators and perturbation theory. Zbl 1065.81054
Caliceti, Emanuela; Graffi, Sandro; Sjöstrand, Johannes
2005
Nonselfadjoint perturbations of selfadjoint operators in two dimensions: II. Vanishing averages. Zbl 1096.47053
Hitrik, Michael; Sjöstrand, Johannes
2005
Pseudospectra of semiclassical (pseudo-) differential operators. Zbl 1054.35035
Dencker, Nils; Sjöstrand, Johannes; Zworski, Maciej
2004
The inverse spectral problem. Zbl 1061.58029
Zelditch, Steve
2004
Hitrik, Michael; Sjöstrand, Johannes
2004
Functional calculus for non-commuting operators with real spectra via an iterated Cauchy formula. Zbl 1070.47009
2004
Resonances associated to a closed hyperbolic trajectory in dimension 2. Zbl 1060.35096
Sjöstrand, Johannes
2003
Bohr-Sommerfeld quantization condition for non-selfadjoint operators in dimension 2. Zbl 1061.35186
Melin, Anders; Sjöstrand, Johannes
2003
Pseudospectrum for differential operators. Zbl 1061.35067
Sjöstrand, Johannes
2003
Birkhoff normal forms in semi-classical inverse problems. Zbl 1258.35208
Iantchenko, Alexai; Sjöstrand, Johannes; Zworski, Maciej
2002
Quantum monodromy and semi-classical trace formulæ. Zbl 1038.58033
Sjöstrand, Johannes; Zworski, Maciej
2002
Birkhoff normal forms for Fourier integral operators. II. Zbl 1011.35144
Iantchenko, A.; Sjöstrand, J.
2002
Determinants of pseudodifferential operators and complex deformations of phase space. Zbl 1082.35176
Melin, A.; Sjöstrand, J.
2002
Resonances for bottles and trace formulae. Zbl 0979.35109
Sjöstrand, Johannes
2001
Trace formula for resonances in small domains. Zbl 1068.47055
Bony, Jean-François; Sjöstrand, Johannes
2001
Quantum resonances and trapped trajectories. Zbl 1172.35471
Sjöstrand, Johannes
2001
Bohr-Sommerfeld quantization condition for non-selfadjoint operators in dimension 2. Zbl 1066.53141
Sjöstrand, Johannes
2001
Asymptotic distribution of eigenfrequencies for damped wave equations. Zbl 0984.35121
Sjöstrand, Johannes
2000
Correlation asymptotics of classical lattice spin systems with nonconvex Hamilton function at low temperature. Zbl 1021.82002
Bach, V.; Jecko, T.; Sjöstrand, J.
2000
Spectral asymptotics in the semi-classical limit. Zbl 0926.35002
Dimassi, Mouez; Sjöstrand, Johannes
1999
Asymptotic distribution of resonances for convex obstacles. Zbl 0989.35099
Sjöstrand, Johannes; Zworski, Maciej
1999
Supersymmetric measures and maximum principles in the complex domain. Exponential decay of Green’s functions. Zbl 0941.47033
Sjöstrand, J.; Wang, W.-M.
1999
Exponential decay of averaged Green functions for random Schrödinger operators. A direct approach. Zbl 0934.35036
Sjöstrand, J.; Wang, W.-M.
1999
Evolution equations, Feshbach resonances, singular Hodge theory. Zbl 0918.00012
1999
A trace formula and review of some estimates for resonances. Zbl 0877.35090
Sjöstrand, J.
1997
Asymptotics of the number of Rayleigh resonances. Zbl 0890.35098
Sjöstrand, Johannes; Vodev, Georgi
1997
A trace formula for resonances and applications to semi-classical Schrödinger operators. Zbl 1061.35506
Sjöstrand, J.
1997
Spectral theory, microlocal analysis, singular manifolds. Zbl 0882.00015
1997
Correlation asymptotics and Witten Laplacians. Zbl 0877.35084
Sjöstrand, J.
1996
Density of resonances for strictly convex analytic obstacles. With an appendix by M. Zworski. Zbl 0863.35072
Sjöstrand, Johannes
1996
Function spaces associated to global $$I$$-Lagrangian manifolds. Zbl 0889.46027
Sjöstrand, Johannes
1996
Transport properties in resonant tunneling heterostructures. Zbl 0868.35112
Presilla, Carlo; Sjöstrand, Johannes
1996
Trace asymptotics via almost analytic extensions. Zbl 0864.35078
Dimassi, Mouez; Sjöstrand, Johannes
1996
Wiener type algebras of pseudodifferential operators. Zbl 0880.35145
Sjöstrand, J.
1995
On Schrödinger equations with concentrated nonlinearities. Zbl 0820.34050
Jona-Lasinio, Giovanni; Presilla, Carlo; Sjöstrand, Johannes
1995
The complex scaling method for scattering by strictly convex obstacles. Zbl 0839.35095
Sjöstrand, Johannes; Zworski, Maciej
1995
An algebra of pseudodifferential operators. Zbl 0840.35130
Sjöstrand, Johannes
1994
Microlocal analysis for differential operators. An introduction. Zbl 0804.35001
Grigis, Alain; Sjöstrand, Johannes
1994
On the correlation for Kac-like models in the convex case. Zbl 0946.35508
Helffer, Bernard; Sjöstrand, Johannes
1994
Lower bounds on the number of scattering poles. II. Zbl 0823.35137
Sjöstrand, Johannes; Zworski, Maciej
1994
Evolution equations in a large number of variables. Zbl 0837.35061
Sjöstrand, Johannes
1994
Ferromagnetic integrals, correlations and maximum principles. Zbl 0831.35031
Sjöstrand, Johannes
1994
Remark on extensions of the Watermelon theorem. Zbl 0842.35003
Sjöstrand, Johannes
1994
Erratum on the paper: Semiclassical expansions of the thermodynamic limit for a Schrödinger equation. II: The double well case. Zbl 0979.35521
Helffer, Bernard; Sjöstrand, Johannes
1994
Schrödinger operators in high dimensions, asymptotic constructions and estimates. Zbl 0842.35094
Sjöstrand, Johannes
1994
Lower bounds on the number of scattering poles. Zbl 0784.35070
Sjöstrand, Johannes; Zworski, Maciej
1993
Potential wells in high dimensions. I. Zbl 0770.35050
Sjöstrand, Johannes
1993
Adiabatic projections from the pseudodifferential point of view. (Projecteurs adiabatiques du point de vue pseudodifférentiel.) Zbl 0783.35087
Sjöstrand, Johannes
1993
Potential wells in high dimensions. II: More about the one well case. Zbl 0770.35051
Sjöstrand, Johannes
1993
...and 85 more Documents
all top 5
### Cited by 1,540 Authors
77 Sjöstrand, Johannes 68 Helffer, Bernard 33 Martinez, André 33 Zworski, Maciej 23 Uhlmann, Gunther Alberto 20 Zelditch, Steve 19 Nicola, Fabio 19 Petkov, Vesselin M. 18 Cordero, Elena 18 Gröchenig, Karlheinz 18 Lebeau, Gilles 18 Vasy, András 17 Gérard, Christian 17 Toft, Joachim 16 Guillarmou, Colin 15 Bony, Jean-François 15 Kian, Yavar 15 Nakamura, Shu 15 Salo, Mikko 14 Bellassoued, Mourad 14 Burq, Nicolas 14 Dyatlov, Semyon 14 Klopp, Frédéric 14 Lassas, Matti J. 14 Pravda-Starov, Karel 14 Stoyanov, Luchezar N. 13 Bove, Antonio 13 Bruneau, Vincent 13 Cornean, Horia D. 13 Hsiao, Chin-Yu 13 Klein, Markus 13 Vodev, Georgi 12 Galkowski, Jeffrey 12 Hérau, Frédéric 12 Hitrik, Michael 12 Nier, Francis 12 Paoletti, Roberto 12 Purice, Radu 12 Robert, Didier 12 Stefanov, Plamen D. 11 Dimassi, Mouez 11 Himonas, A. Alexandrou 11 Lascar, Richard 11 Raikov, Georgi D. 11 Ramond, Thierry 11 Raymond, Nicolas 11 Rivière, Gabriel 11 Rodino, Luigi 11 Sordoni, Vania 11 Vũ Ngọc, San 11 Wunsch, Jared 10 Fujiié, Setsuro 10 Hassell, Andrew 10 Korotyaev, Evgeny L. 10 Nonnenmacher, Stéphane 10 Trapasso, Salvatore Ivan 10 Tzou, Leo 9 Briet, Philippe 9 Guillemin, Victor W. 9 Hanges, Nicholas William 9 Lascar, Bernard 9 Le Rousseau, Jérôme H. 9 Ludwig, Ursula Beate 9 Mughetti, Marco 9 Oksanen, Lauri 9 Pushnitski, Alexander B. 9 Vögel, Martin 9 Yamamoto, Masahiro 9 Zerzeri, Maher 8 Anikin, A. Yu. 8 Christiansen, Tanya J. 8 de Gosson, Maurice Alexis 8 Grigis, Alain 8 Hislop, Peter D. 8 Iantchenko, Alexei 8 Krantz, Steven George 8 Morame, Abderemane 8 Nourrigat, Jean Francois 8 Rosenberger, Elke 8 Rouleux, Michel 8 Sun, Qiyu 8 Teufel, Stefan 8 Tomita, Naohito 8 Weich, Tobias 8 Williams, Mark 7 Borthwick, David 7 Charles, Laurent 7 Christianson, Hans 7 Coriasco, Sandro 7 Dobrokhotov, Sergei Yurievich 7 Faure, Frédéric 7 Fermanian-Kammerer, Clotilde 7 Jin, Long 7 Le Peutrec, Dorian 7 Lin, Yi-Hsuan 7 Măntoiu, Marius Laurențiu 7 Parmeggiani, Alberto 7 Popoff, Nicolas 7 Romero, José Luis 7 Sigal, Israel Michael ...and 1,440 more Authors
all top 5
### Cited in 244 Serials
152 Communications in Mathematical Physics 131 Journal of Functional Analysis 131 Communications in Partial Differential Equations 63 Annales de l’Institut Fourier 61 Journal of Differential Equations 57 Journal of Mathematical Physics 55 Duke Mathematical Journal 55 Annales Henri Poincaré 52 Transactions of the American Mathematical Society 51 Journal of Mathematical Analysis and Applications 51 Annales de l’Institut Henri Poincaré. Physique Théorique 31 The Journal of Geometric Analysis 30 Inventiones Mathematicae 29 Mathematische Annalen 29 Journal de Mathématiques Pures et Appliquées. Neuvième Série 28 Journal d’Analyse Mathématique 28 Advances in Mathematics 28 Proceedings of the American Mathematical Society 28 Comptes Rendus. Mathématique. Académie des Sciences, Paris 26 Journal of Spectral Theory 22 Letters in Mathematical Physics 22 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 22 Publications of the Research Institute for Mathematical Sciences, Kyoto University 20 Inverse Problems and Imaging 19 Reviews in Mathematical Physics 19 The Journal of Fourier Analysis and Applications 17 Inverse Problems 17 Arkiv för Matematik 17 Proceedings of the Japan Academy. Series A 17 SIAM Journal on Mathematical Analysis 17 Journal of Pseudo-Differential Operators and Applications 15 Mathematische Nachrichten 15 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 14 Mathematische Zeitschrift 12 Applicable Analysis 12 Bulletin of the American Mathematical Society. New Series 11 Annals of Global Analysis and Geometry 11 Journal of the Institute of Mathematics of Jussieu 10 Journal of Statistical Physics 10 Journal of Geometry and Physics 10 Annali di Matematica Pura ed Applicata. Serie Quarta 10 Integral Equations and Operator Theory 10 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 10 Geometric and Functional Analysis. GAFA 10 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 10 Journal of the European Mathematical Society (JEMS) 9 Archive for Rational Mechanics and Analysis 9 Theoretical and Mathematical Physics 9 Mémoires de la Société Mathématique de France. Nouvelle Série 8 Bulletin de la Société Mathématique de France 8 Asymptotic Analysis 8 Russian Journal of Mathematical Physics 8 Applied and Computational Harmonic Analysis 7 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 7 Memoirs of the American Mathematical Society 7 Journal of the American Mathematical Society 7 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 7 St. Petersburg Mathematical Journal 7 Journal of Inverse and Ill-Posed Problems 7 Discrete and Continuous Dynamical Systems 7 Bulletin of Mathematical Sciences 6 Communications on Pure and Applied Mathematics 6 Mathematical Notes 6 Nonlinearity 6 Acta Mathematica 6 The Annals of Probability 6 Monatshefte für Mathematik 6 Osaka Journal of Mathematics 6 International Journal of Mathematics 6 Annals of Mathematics. Second Series 6 Proceedings of the Japan Academy 5 Rocky Mountain Journal of Mathematics 5 Functional Analysis and its Applications 5 Journal of the Mathematical Society of Japan 5 Journal of Soviet Mathematics 5 Manuscripta Mathematica 5 Ergodic Theory and Dynamical Systems 5 Revista Matemática Iberoamericana 5 Indagationes Mathematicae. New Series 5 Calculus of Variations and Partial Differential Equations 5 Bulletin des Sciences Mathématiques 5 Mathematical Physics, Analysis and Geometry 5 Communications in Contemporary Mathematics 5 Proceedings of the Steklov Institute of Mathematics 5 Analysis & PDE 5 Advances in Mathematical Physics 5 Science China. Mathematics 5 Journal de l’École Polytechnique – Mathématiques 4 Israel Journal of Mathematics 4 Journal für die Reine und Angewandte Mathematik 4 Michigan Mathematical Journal 4 Nagoya Mathematical Journal 4 Constructive Approximation 4 Stochastic Processes and their Applications 4 Acta Mathematica Sinica. English Series 4 Communications on Pure and Applied Analysis 4 Bulletin of the American Mathematical Society 4 Complex Analysis and Operator Theory 4 Analysis and Mathematical Physics 4 Séminaire Laurent Schwartz. EDP et Applications ...and 144 more Serials
all top 5
### Cited in 53 Fields
1,336 Partial differential equations (35-XX) 575 Quantum theory (81-XX) 467 Operator theory (47-XX) 382 Global analysis, analysis on manifolds (58-XX) 181 Several complex variables and analytic spaces (32-XX) 142 Statistical mechanics, structure of matter (82-XX) 141 Differential geometry (53-XX) 118 Functional analysis (46-XX) 112 Dynamical systems and ergodic theory (37-XX) 104 Harmonic analysis on Euclidean spaces (42-XX) 94 Ordinary differential equations (34-XX) 86 Probability theory and stochastic processes (60-XX) 66 Optics, electromagnetic theory (78-XX) 50 Numerical analysis (65-XX) 38 Systems theory; control (93-XX) 32 Integral transforms, operational calculus (44-XX) 29 Functions of a complex variable (30-XX) 25 Linear and multilinear algebra; matrix theory (15-XX) 25 Mechanics of deformable solids (74-XX) 24 Topological groups, Lie groups (22-XX) 24 Relativity and gravitational theory (83-XX) 22 Information and communication theory, circuits (94-XX) 21 Fluid mechanics (76-XX) 20 Mechanics of particles and systems (70-XX) 18 Manifolds and cell complexes (57-XX) 17 Abstract harmonic analysis (43-XX) 15 Potential theory (31-XX) 15 Difference and functional equations (39-XX) 14 Algebraic geometry (14-XX) 14 Integral equations (45-XX) 13 Number theory (11-XX) 13 Calculus of variations and optimal control; optimization (49-XX) 12 Special functions (33-XX) 11 Measure and integration (28-XX) 11 Biology and other natural sciences (92-XX) 10 Approximations and expansions (41-XX) 6 History and biography (01-XX) 6 Combinatorics (05-XX) 6 $$K$$-theory (19-XX) 6 Real functions (26-XX) 5 Sequences, series, summability (40-XX) 5 Convex and discrete geometry (52-XX) 5 Geophysics (86-XX) 4 Group theory and generalizations (20-XX) 4 Algebraic topology (55-XX) 2 General and overarching topics; collections (00-XX) 2 Associative rings and algebras (16-XX) 2 Nonassociative rings and algebras (17-XX) 2 Statistics (62-XX) 2 Astronomy and astrophysics (85-XX) 1 Mathematical logic and foundations (03-XX) 1 Geometry (51-XX) 1 Operations research, mathematical programming (90-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2022-05-18T10:27:35 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5822024941444397, "perplexity": 8723.23002536329}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662521883.7/warc/CC-MAIN-20220518083841-20220518113841-00389.warc.gz"}
|
http://pdglive.lbl.gov/Particle.action;jsessionid=713CDCCEA231F9B59ECE13077BF54AB5?node=S077&init=0
|
LEPTONS INSPIRE search
# Heavy Neutral Leptons, Searches for
(A) Heavy Neutral Leptons
Stable Neutral Heavy Lepton MASS LIMITS
Mass $\mathit m$ $>39.5$ GeV CL=95.0%
Heavy Neutral Lepton MASS LIMITS $>80.5$ GeV CL=95.0%
Astrophysical Limits on Neutrino MASS for ${\mathit m}_{{{\mathit \nu}}}$ $>$ 1 GeV
(B) Other Bounds from Nuclear and Particle Decays
Limits on $\vert \mathit U_{{{\mathit e}}\mathit x}\vert ^2$ as Function of ${\mathit m}_{{{\mathit \nu}_{{x}}}}$
Peak and kink search tests $<1 \times 10^{-7}$ CL=90.0%
Kink search in nuclear ${{\mathit \beta}}$ decay
Searches for Decays of Massive ${{\mathit \nu}}$
Limits on Coupling of ${{\mathit \mu}}$ to ${{\mathit \nu}_{{x}}}$ as Function of ${\mathit m}_{{{\mathit \nu}_{{x}}}}$
Peak search test
Peak search test
Peak Search in Muon Capture
Searches for Decays of Massive ${{\mathit \nu}}$
Limits on $\vert \mathit U_{{{\mathit \tau}}\mathit x}\vert ^2$ as a Function of ${\mathit m}_{{{\mathit \nu}_{{x}}}}$
Limits on $\vert \mathit U_{\mathit a\mathit x}\vert ^2$
Limits on $\vert \mathit U_{1\mathit j}{\times }\mathit U_{2\mathit j}\vert$ as Function of ${\mathit m}_{{{\mathit \nu}_{{j}}}}$
| 2018-04-26T11:22:00 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9653381705284119, "perplexity": 3317.258485732627}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-17/segments/1524125948126.97/warc/CC-MAIN-20180426105552-20180426125552-00351.warc.gz"}
|
http://www.malinc.se/math/statistics/binomialen.php
|
Binomial Distribution
In a Bernoulli trial the outcome can be either "success" or "failure". If $$p$$ denotes the probability of success then the probability of failure is $$1-p$$. When doing $$n$$ trials the probability of getting exactly $$k$$ successes is given by
$P\;(X=x)=\binom{n}{k}p^k(1-p)^{n-k}$
where $$X$$ is a binomially distributed random variable. We use the notation: $$X\sim B(n,p)$$.
Mean and variance for binomial distribution
The mean of one trial is given by $$\mu = 1\cdot p+0\cdot (1-p)=p$$. The mean of $$n$$ independent trials is hence $$\mu = np$$.
The variance of one trial is given by
$\sigma^2=(1-\mu)^2\cdot p + (0-\mu)^2\cdot (1-p)= (1-p)^2\cdot p + p^2\cdot (1-p)=p\cdot (1-p)$
The variance of $$n$$ independent trials is hence $$\sigma^2=np(1-p)$$.
$\mu = np \hspace{1cm} \sigma^2=np(1-p)$
Binomial distribution in GeoGebra
By using the tool "Probability Calculator" , you can find all probabilities for a binomial distribution.
Binomial and normal distribution
Using the mean $$\mu = np$$ and the variance $$\sigma^2=np(1-p)$$ of the binomial distribution as parameters in the function describing the normal pdf
$f(x)=\frac{1}{\sigma \sqrt{2\pi}}e^{\left( - \dfrac{(x-\mu)^2}{2\sigma^2}\right)}$
we get a continuous approximation of the binomial distribution. When $$n$$ is large and when $$p$$ is not too close to 0 or 1, the normal distribution is a very good approximation of the binomial distribution.
by Malin Christersson under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Sweden License
www.malinc.se
| 2018-09-19T15:00:31 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9420760273933411, "perplexity": 195.88179904502982}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267156252.31/warc/CC-MAIN-20180919141825-20180919161825-00292.warc.gz"}
|
https://www.zbmath.org/authors/?q=ai%3Ajohnson.selmer-m
|
zbMATH — the first resource for mathematics
Johnson, Selmer M.
Compute Distance To:
Author ID: johnson.selmer-m Published as: Johnson, S.; Johnson, S. M.; Johnson, Selmer; Johnson, Selmer M. Homepage: http://www.rand.org/pubs/authors/j/johnson_selmer_martin.html External Links: MGP · Wikidata · dblp
Documents Indexed: 22 Publications since 1954
all top 5
Co-Authors
12 single-authored 4 Dantzig, George Bernard 2 Fulkerson, Delbert R. 1 Bradt, Russell N. 1 Chvátal, Vašek 1 Cook, William John 1 Ford, Lester Randolph jun. 1 Fulkerson, R. 1 Gross, Christian 1 Karlin, Samuel 1 Morant, M. J. 1 White, Wayne
all top 5
Serials
3 Management Science 2 IEEE Transactions on Information Theory 2 Mathematics of Computation 2 Operations Research 1 American Mathematical Monthly 1 Discrete Mathematics 1 Canadian Journal of Mathematics 1 Transactions of the American Mathematical Society 1 Utilitas Mathematica 1 1 Mathematical Tables and other Aids to Computation 1 Annals of Mathematics Studies 1 Annals of Mathematical Statistics 1 IRE Transactions on Information Theory
Fields
6 Operations research, mathematical programming (90-XX) 5 Information and communication theory, circuits (94-XX) 1 History and biography (01-XX) 1 Combinatorics (05-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX)
Citations contained in zbMATH Open
20 Publications have been cited 961 times in 939 Documents Cited by Year
Optimal two- and three-stage production schedules with set-up time included. Zbl 1349.90359
Johnson, S. M.
1954
Solution of a large-scale traveling-salesman problem. Zbl 1414.90372
Dantzig, G.; Fulkerson, R.; Johnson, S.
1954
A new upper bound for error-correcting codes. Zbl 0102.34602
Johnson, Selmer M.
1962
A linear diophantine problem. Zbl 0096.02803
Johnson, S. M.
1960
Generation of permutations by adjacent transposition. Zbl 0114.01203
Johnson, S. M.
1963
On sequential designs for maximizing the sum of $$n$$ observations. Zbl 0073.14203
Bradt, R. N.; Johnson, S. M.; Karlin, S.
1956
A tournament problem. Zbl 0092.01303
Ford, Lester R. jun.; Johnson, Selmer M.
1959
A linear programming approach to the chemical equilibrium problem. Zbl 0995.90596
Dantzig, George; Johnson, Selmer; White, Wayne
1958
Upper bounds for constant weight error correcting codes. Zbl 0248.94023
Johnson, Selmer
1972
Sequential production planning over time at minimum cost. Zbl 0995.90530
Johnson, S. M.
1957
On upper bounds for unrestricted binary error-correcting codes. Zbl 0231.94008
Johnson, Selmer M.
1971
A new lower bound for coverings by rook domains. Zbl 0265.05011
Johnson, S. M.
1972
On a linear-programming, combinatorial approach to the traveling-salesman problem. Zbl 1414.90211
Dantzig, G. B.; Fulkerson, D. R.; Johnson, S. M.
1959
Improved asymptotic bounds for error-correcting codes. Zbl 0282.94010
Johnson, Selmer M.
1963
A search game. Zbl 0126.16302
Johnson, Selmer M.
1964
Discussion: sequencing $$n$$ jobs on two machines with arbitrary time lags. Zbl 0995.90537
Johnson, S. M.
1959
Solution of a large-scale traveling-salesman problem. Zbl 1187.90007
Chvátal, Vašek; Cook, William; Dantzig, George B.; Fulkerson, Delbert R.; Johnson, Selmer M.
2010
An elementary remark on maximal gaps between successive primes. Zbl 0147.03103
Johnson, S. M.
1965
Sequential minimax search for a zero of a convex function. Zbl 0114.06202
Gross, C.; Johnson, S. M.
1959
On the representations of an integers as the sum of products of integers. Zbl 0055.27204
Johnson, S. M.
1954
Solution of a large-scale traveling-salesman problem. Zbl 1187.90007
Chvátal, Vašek; Cook, William; Dantzig, George B.; Fulkerson, Delbert R.; Johnson, Selmer M.
2010
Upper bounds for constant weight error correcting codes. Zbl 0248.94023
Johnson, Selmer
1972
A new lower bound for coverings by rook domains. Zbl 0265.05011
Johnson, S. M.
1972
On upper bounds for unrestricted binary error-correcting codes. Zbl 0231.94008
Johnson, Selmer M.
1971
An elementary remark on maximal gaps between successive primes. Zbl 0147.03103
Johnson, S. M.
1965
A search game. Zbl 0126.16302
Johnson, Selmer M.
1964
Generation of permutations by adjacent transposition. Zbl 0114.01203
Johnson, S. M.
1963
Improved asymptotic bounds for error-correcting codes. Zbl 0282.94010
Johnson, Selmer M.
1963
A new upper bound for error-correcting codes. Zbl 0102.34602
Johnson, Selmer M.
1962
A linear diophantine problem. Zbl 0096.02803
Johnson, S. M.
1960
A tournament problem. Zbl 0092.01303
Ford, Lester R. jun.; Johnson, Selmer M.
1959
On a linear-programming, combinatorial approach to the traveling-salesman problem. Zbl 1414.90211
Dantzig, G. B.; Fulkerson, D. R.; Johnson, S. M.
1959
Discussion: sequencing $$n$$ jobs on two machines with arbitrary time lags. Zbl 0995.90537
Johnson, S. M.
1959
Sequential minimax search for a zero of a convex function. Zbl 0114.06202
Gross, C.; Johnson, S. M.
1959
A linear programming approach to the chemical equilibrium problem. Zbl 0995.90596
Dantzig, George; Johnson, Selmer; White, Wayne
1958
Sequential production planning over time at minimum cost. Zbl 0995.90530
Johnson, S. M.
1957
On sequential designs for maximizing the sum of $$n$$ observations. Zbl 0073.14203
Bradt, R. N.; Johnson, S. M.; Karlin, S.
1956
Optimal two- and three-stage production schedules with set-up time included. Zbl 1349.90359
Johnson, S. M.
1954
Solution of a large-scale traveling-salesman problem. Zbl 1414.90372
Dantzig, G.; Fulkerson, R.; Johnson, S.
1954
On the representations of an integers as the sum of products of integers. Zbl 0055.27204
Johnson, S. M.
1954
all top 5
Cited by 1,481 Authors
20 Lin, Bertrand Miao-Tsong 17 Gupta, Jatinder N. D. 16 Ruiz, Rubén 16 Strusevich, Vitaly A. 15 Cheng, Tai-Chiu Edwin 15 Werner, Frank 12 Rajendran, Chandrasekharan 11 Hadda, Hatem 11 Koulamas, Christos P. 11 Laporte, Gilbert 10 Ji, Lijun 10 Potts, Chris N. 9 Rosales, José Carlos 9 Sotskov, Yuri N. 8 Bagga, P. C. 8 Dong, Jianming 8 Kamburowski, Jerzy 8 Lin, Guohui 7 Dridi, Najoua 7 Hu, Jueliang 7 Kovalyov, Mikhail Yakovlevich 7 T’kindt, Vincent 6 Billaut, Jean-Charles 6 Błażewicz, Jacek 6 Brucker, Peter J. 6 Chang, Yanxun 6 Framinan, Jose M. 6 Lee, Chung-Yee 6 Mosheiov, Gur 6 Pesch, Erwin 6 Semet, Frédéric 6 Sriskandarajah, Chelliah 6 Wang, Jibo 5 Allahverdi, Ali 5 Della Croce, Federico 5 Fel, Leonid G. 5 Kalczynski, Pawel Jan 5 Kim, Yeong-Dae 5 Kyparisis, George J. 5 Nowicki, Eugeniusz 5 Oulamara, Ammar 5 Sevastyanov, Sergeĭ Vasil’evich 5 Stützle, Thomas G. 5 Szwarc, Włodzimierz 5 Tripathi, Amitabha 5 Vajnovszki, Vincent 5 Zinov’ev, Viktor Aleksandrovich 4 Asef-Vaziri, Ardavan 4 Bao, Jingjun 4 Branco, Manuel Batista 4 Breit, Joachim 4 Chen, Jian-er 4 Chen, Xin 4 García Sánchez, Pedro A. 4 Gouveia, Luis 4 Hajri-Gabouj, Sonia 4 Hwang, Feng-Jang 4 Knust, Sigrid 4 Lucena, Abilio 4 Maroto, Concepción 4 Östergård, Patric R. J. 4 Pan, Quanke 4 Ruskey, Frank 4 Schmidt, Günter 4 Sen, Tapan 4 Sethi, Suresh P. 4 Steiner, George 4 Tang, Lixin 4 Tong, Weitian 4 Wang, Jianxin 4 Wu, Guangwei 4 Yang, Dar-Li 4 Yin, Jianxing 4 Ziegler, Hans 3 Bart, Harm 3 Bassalygo, Leonid A. 3 Beck, Matthias 3 Bernini, Antonio 3 Boudhar, Mourad 3 Bouquard, Jean-Louis 3 Cattaruzza, Diego 3 Cheng, Jinliang 3 Choi, Byung-Cheon 3 Clayton, Murray K. 3 Dileepan, Parthasarati 3 Dubois-Lacoste, Jérémie 3 Fan, Baoqiang 3 Feng, Tao 3 Fernandez-Viagas, Victor 3 Fischer, Anja 3 Ge, Gennian 3 Han, Xin 3 Haouari, Mohamed 3 Hariri, A. M. A. 3 Ho, Johnny C. 3 Hoogeveen, Johannes Adzer 3 Huang, Hsiao-Lan 3 Janiak, Adam 3 Kononov, Aleksandr 3 Kononov, Alexander V. ...and 1,381 more Authors
all top 5
Cited in 171 Serials
208 European Journal of Operational Research 99 Computers & Operations Research 38 Journal of Scheduling 35 Discrete Applied Mathematics 34 International Journal of Production Research 33 Operations Research Letters 27 Discrete Mathematics 22 Annals of Operations Research 20 Information Processing Letters 19 Theoretical Computer Science 19 Designs, Codes and Cryptography 15 Journal of Combinatorial Optimization 11 Journal of Information & Optimization Sciences 10 Applied Mathematics and Computation 9 Asia-Pacific Journal of Operational Research 8 Journal of Combinatorial Theory. Series A 8 Opsearch 8 Mathematical Problems in Engineering 7 OR Spectrum 6 Computers & Mathematics with Applications 6 Information Sciences 6 Journal of Number Theory 6 Mathematical and Computer Modelling 6 Journal of Global Optimization 6 Linear Algebra and its Applications 6 RAIRO. Operations Research 6 Optimization Letters 5 Journal of Computer and System Sciences 5 Applied Mathematical Modelling 5 Discrete Dynamics in Nature and Society 5 Functional Analysis and Other Mathematics 4 Metrika 4 Problems of Information Transmission 4 Mathematics of Computation 4 Semigroup Forum 4 Zeitschrift für Operations Research. Serie A: Theorie 4 Journal of Combinatorial Designs 3 International Journal of Systems Science 3 Mathematical Notes 3 Journal of Soviet Mathematics 3 European Journal of Combinatorics 3 OR Spektrum 3 Optimization 3 Algorithmica 3 SIAM Journal on Discrete Mathematics 3 ZOR. Zeitschrift für Operations Research 3 Mathematical Programming. Series A. Series B 3 Applied Mathematics. Series B (English Edition) 3 Computational and Applied Mathematics 3 Finite Fields and their Applications 3 Top 3 Optimization and Engineering 3 Journal of Applied Mathematics 3 4OR 3 Journal of Discrete Algorithms 3 Cryptography and Communications 3 Diskretnyĭ Analiz i Issledovanie Operatsiĭ 3 Journal of the Operations Research Society of China 3 Journal of Mathematical Modelling and Algorithms in Operations Research 2 The Annals of Statistics 2 BIT 2 Journal of Optimization Theory and Applications 2 Journal of Statistical Planning and Inference 2 Cybernetics 2 Statistics & Probability Letters 2 Order 2 Graphs and Combinatorics 2 Automation and Remote Control 2 Stochastic Processes and their Applications 2 Computational Optimization and Applications 2 Combinatorics, Probability and Computing 2 International Transactions in Operational Research 2 Optimization Methods & Software 2 Soft Computing 2 Mathematical Methods of Operations Research 2 Annals of Combinatorics 2 Integers 2 JMMA. Journal of Mathematical Modelling and Algorithms 2 Journal of Applied Mathematics and Computing 2 Discrete Optimization 2 Naval Research Logistics Quarterly 2 Unternehmensforschung 2 Advances in Mathematics of Communications 2 Algorithms 1 Acta Informatica 1 Advances in Applied Probability 1 American Mathematical Monthly 1 Artificial Intelligence 1 Communications in Algebra 1 Indian Journal of Pure & Applied Mathematics 1 Israel Journal of Mathematics 1 Journal of the Franklin Institute 1 Journal of Mathematical Analysis and Applications 1 Advances in Mathematics 1 Annals of the Institute of Statistical Mathematics 1 Archiv der Mathematik 1 Automatica 1 Journal of Algebra 1 Journal of Combinatorial Theory. Series B 1 Journal of Pure and Applied Algebra ...and 71 more Serials
all top 5
Cited in 29 Fields
705 Operations research, mathematical programming (90-XX) 173 Computer science (68-XX) 99 Combinatorics (05-XX) 74 Information and communication theory, circuits (94-XX) 44 Numerical analysis (65-XX) 40 Number theory (11-XX) 29 Group theory and generalizations (20-XX) 17 Statistics (62-XX) 14 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 9 Systems theory; control (93-XX) 7 Geometry (51-XX) 7 Probability theory and stochastic processes (60-XX) 6 Order, lattices, ordered algebraic structures (06-XX) 6 Calculus of variations and optimal control; optimization (49-XX) 6 Convex and discrete geometry (52-XX) 5 Linear and multilinear algebra; matrix theory (15-XX) 3 History and biography (01-XX) 3 Algebraic geometry (14-XX) 3 Biology and other natural sciences (92-XX) 1 General and overarching topics; collections (00-XX) 1 Mathematical logic and foundations (03-XX) 1 Commutative algebra (13-XX) 1 Harmonic analysis on Euclidean spaces (42-XX) 1 Operator theory (47-XX) 1 Algebraic topology (55-XX) 1 Manifolds and cell complexes (57-XX) 1 Mechanics of particles and systems (70-XX) 1 Statistical mechanics, structure of matter (82-XX) 1 Mathematics education (97-XX)
Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-05-06T07:41:51 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.36980047821998596, "perplexity": 8368.578760898969}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988741.20/warc/CC-MAIN-20210506053729-20210506083729-00432.warc.gz"}
|
https://par.nsf.gov/biblio/10227977-early-science-from-possum-shocks-turbulence-massive-new-reservoir-ionised-gas-fornax-cluster
|
Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster
Abstract We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster—the Fornax cluster—which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe’s Magnetism (POSSUM) covering a ${\sim}34$ square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ${\sim}25$ RMs per square degree from a 280-MHz band centred at 887 MHz, which is similar to expectations for forthcoming GHz-frequency ${\sim}3\pi$ -steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by $16.8\pm2.4$ rad m −2 within 1 $^\circ$ (360 kpc) projected distance to the cluster centre, which is 2–4 times larger than the spatial extent of the presently detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM and exists in a density regime that broadly matches expectations for moderately dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be a more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10227977
Journal Name:
Publications of the Astronomical Society of Australia
Volume:
38
ISSN:
1323-3580
1. ABSTRACT We present the results from an Australian Square Kilometre Array Pathfinder search for radio variables on timescales of hours. We conducted an untargeted search over a 30 deg2 field, with multiple 10-h observations separated by days to months, at a central frequency of 945 MHz. We discovered six rapid scintillators from 15-min model-subtracted images with sensitivity of $\sim\! 200\, \mu$Jy/beam; two of them are extreme intra-hour variables with modulation indices up to $\sim 40{{\ \rm per\ cent}}$ and timescales as short as tens of minutes. Five of the variables are in a linear arrangement on the sky with angular width ∼1 arcminmore »
Quasar absorption-line studies in the ultraviolet (UV) can uniquely probe the nature of the multiphase cool–warm (104 < T < 106 K) gas in and around galaxy clusters, promising to provide unprecedented insights into (1) interactions between the circumgalactic medium (CGM) associated with infalling galaxies and the hot (T > 106 K) X-ray emitting intracluster medium (ICM), (2) the stripping of metal-rich gas from the CGM, and (3) a multiphase structure of the ICM with a wide range of temperatures and metallicities. In this work, we present results from a high-resolution simulation of an $\sim 10^{14} \, \mathrm{M}_{\odot }$ galaxy clustermore »
5. ABSTRACT The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4 GHz) to a r.m.s. of $7\, \mu {\rm Jy}\,$beam−1 over an area of $\sim 1\, {\rm deg}^2$ centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements with the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity out to z ∼ 1. In this paper we give anmore »
| 2022-08-16T23:22:48 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5245231986045837, "perplexity": 2929.2366853501667}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882572581.94/warc/CC-MAIN-20220816211628-20220817001628-00048.warc.gz"}
|
https://par.nsf.gov/biblio/10376733-characterizing-mitigating-impact-telluric-absorption-precise-radial-velocities
|
Characterizing and Mitigating the Impact of Telluric Absorption in Precise Radial Velocities
Abstract
Precise radial velocity (PRV) surveys are important for the search for Earth analogs around nearby bright stars, which induce a small stellar reflex motion with an RV amplitude of ∼10 cm s−1. Detecting such a small RV signal poses challenges to instrumentation, data analysis, and the precision of astrophysical models to mitigate stellar jitter. In this work, we investigate an important component in the PRV error budget—the spectral contamination from the Earth’s atmosphere (tellurics). We characterize the effects of telluric absorption on the RV precision and quantify its contribution to the RV error budget over time and across a wavelength range of 350 nm–2.5μm. We use simulated solar spectra with telluric contamination injected, and we extract the RVs using two commonly adopted algorithms: dividing out a telluric model before performing cross-correlation or forward modeling the observed spectrum incorporating a telluric model. We assume various degrees of cleanness in removing the tellurics. We conclude that the RV errors caused by telluric absorption can be suppressed to close to or even below 1–10 cm s−1in the blue optical region. At red through near-infrared wavelengths, however, the residuals of tellurics can induce an RV error on the meter-per-second level even under the more »
Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
NSF-PAR ID:
10376733
Journal Name:
The Astronomical Journal
Volume:
164
Issue:
5
Page Range or eLocation-ID:
Article No. 211
ISSN:
0004-6256
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
##### More Like this
1. The north ecliptic pole (NEP) is an important region for extragalactic surveys. Deep and wide contiguous surveys are being performed by several space observatories, most currently with the eROSITA telescope. Several more are planned for the near future. We analyse all the ROSAT pointed and survey observations in a region of 40 deg 2 around the NEP, restricting the ROSAT field of view to the inner 30′ radius. We obtain an X-ray catalogue of 805 sources with 0.5−2 keV fluxes > 2.9 × 10 −15 erg cm −2 s −1 , about a factor of three deeper than the ROSAT All-Sky Survey in this field. The sensitivity and angular resolution of our data are comparable to the eROSITA All-Sky Survey expectations. The 50% position error radius of the sample of X-ray sources is ∼10″. We use HEROES optical and near-infrared imaging photometry from the Subaru and Canada/France/Hawaii telescopes together with GALEX, SDSS, Pan-STARRS, and WISE catalogues, as well as images from a new deep and wide Spitzer survey in the field to statistically identify the X-ray sources and to calculate photometric redshifts for the candidate counterparts. In particular, we utilize mid-infrared (mid-IR) colours to identify active galactic nucleus (AGN) X-raymore »
2. Abstract
We present results on the nature of extreme ejective feedback episodes and the physical conditions of a population of massive (M*∼ 1011M), compact starburst galaxies atz= 0.4–0.7. We use data from Keck/NIRSPEC, SDSS, Gemini/GMOS, MMT, and Magellan/MagE to measure rest-frame optical and near-IR spectra of 14 starburst galaxies with extremely high star formation rate surface densities (mean ΣSFR∼ 2000Myr−1kpc−2) and powerful galactic outflows (maximum speedsv98∼ 1000–3000 km s−1). Our unique data set includes an ensemble of both emission ([Oii]λλ3726,3729, Hβ, [Oiii]λλ4959,5007, Hα, [Nii]λλ6549,6585, and [Sii]λλ6716,6731) and absorption (Mgiiλλ2796,2803, and Feiiλ2586) lines that allow us to investigate the kinematics of the cool gas phase (T∼ 104K) in the outflows. Employing a suite of line ratio diagnostic diagrams, we find that the central starbursts are characterized by high electron densities (medianne∼ 530 cm−3), and high metallicity (solar or supersolar). We show that the outflows are most likely driven by stellar feedback emerging from the extreme central starburst, rather than by an AGN. We also present multiple intriguing observational signatures suggesting that these galaxies may have substantial Lyman continuum (LyC) photon leakage, including weak [Sii]nebular emission lines. Our results imply that these galaxies may be captured in a short-lived phase of extrememore »
3. ABSTRACT
Ever since they were first detected over 100 yr ago, the mysterious diffuse interstellar bands (DIBs), a set of several hundred broad absorption features seen against distant stars in the optical and near-infrared wavelength range, largely remain unidentified. The close match, both in wavelengths and in relative strengths, recently found between the experimental absorption spectra of gas-phase buckminsterfullerene ions (C$_{60}^{+}$) and four DIBs at $\lambda 9632\, {\rm \mathring{\rm A}}$, $\lambda 9577\, {\rm \mathring{\rm A}}$, $\lambda 9428\, {\rm \mathring{\rm A}}$ and $\lambda 9365\, {\rm \mathring{\rm A}}$ (and, to a lesser degree, a weaker DIB at $\lambda 9348\, {\rm \mathring{\rm A}}$) suggests that C$_{60}^{+}$ is a promising carrier for these DIBs. However, arguments against the C$_{60}^{+}$ identification remain and are mostly concerned with the large variation in the intensity ratios of the $\lambda 9632\, {\rm \mathring{\rm A}}$ and $\lambda 9577\, {\rm \mathring{\rm A}}$ DIBs. In this work, we search for these DIBs in the X-shooter archival data of the European Southern Observatory’s Very Large Telescope, and we identify the $\lambda 9632\, {\rm \mathring{\rm A}}$, $\lambda 9577\, {\rm \mathring{\rm A}}$, $\lambda 9428\, {\rm \mathring{\rm A}}$ and $\lambda 9365\, {\rm \mathring{\rm A}}$ DIBs in a sample of 25 stars. While the \$\lambda 9428\, {\rmmore »
4. Abstract
We have used X-ray data from the Neutron Star Interior Composition Explorer (NICER) to search for long-timescale temporal correlations (“red noise”) in the pulse times of arrival (TOAs) from the millisecond pulsars PSR J1824−2452A and PSR B1937+21. These data more closely track intrinsic noise because X-rays are unaffected by the radio-frequency-dependent propagation effects of the interstellar medium. Our search yields strong evidence (natural log Bayes factor of 9.634 ± 0.016) for red noise in PSR J1824−2452A, but the search is inconclusive for PSR B1937+21. In the interest of future X-ray missions, we devise and implement a method to simulate longer and higher-precision X-ray data sets to determine the timing baseline necessary to detect red noise. We find that the red noise in PSR B1937+21 can be reliably detected in a 5 yr mission with a TOA error of 2μs and an observing cadence of 20 observations per month compared to the 5μs TOA error and 11 observations per month that NICER currently achieves in PSR B1937+21. We investigate detecting red noise in PSR B1937+21 with other combinations of observing cadences and TOA errors. We also find that time-correlated red noise commensurate with an injected stochastic gravitational-wave background having anmore »
5. Abstract
Type Ia supernovae (SNe Ia) are more precise standardizable candles when measured in the near-infrared (NIR) than in the optical. With this motivation, from 2012 to 2017 we embarked on the RAISIN program with the Hubble Space Telescope (HST) to obtain rest-frame NIR light curves for a cosmologically distant sample of 37 SNe Ia (0.2 ≲z≲ 0.6) discovered by Pan-STARRS and the Dark Energy Survey. By comparing higher-zHST data with 42 SNe Ia atz< 0.1 observed in the NIR by the Carnegie Supernova Project, we construct a Hubble diagram from NIR observations (with only time of maximum light and some selection cuts from optical photometry) to pursue a unique avenue to constrain the dark energy equation-of-state parameter,w. We analyze the dependence of the full set of Hubble residuals on the SN Ia host galaxy mass and find Hubble residual steps of size ∼0.06-0.1 mag with 1.5σ−2.5σsignificance depending on the method and step location used. Combining our NIR sample with cosmic microwave background constraints, we find 1 +w= −0.17 ± 0.12 (statistical + systematic errors). The largest systematic errors are the redshift-dependent SN selection biases and the properties of the NIR mass step. We also use these data to measureH0=more »
| 2023-01-29T12:20:54 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5226067304611206, "perplexity": 4322.461897301734}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499713.50/warc/CC-MAIN-20230129112153-20230129142153-00834.warc.gz"}
|
http://journal.svmo.ru/en/archive/article?id=1746
|
#### Middle Volga Mathematical Society Journal
DOI 10.15507/2079-6900.24.202202.141-150
Original article
ISSN 2079-6900 (Print)
ISSN 2587-7496 (Online)
MSC2020 37C05
#### On perturbations of algebraic periodic automorphisms of a two-dimensional torus
V. Z. Grines, D. I. Mints, E. E. Chilina
Higher School of Economics (Nizhny Novgorod, Russian Federation)
Abstract. According to the results of V. Z. Grines and A. N. Bezdenezhnykh, for each gradient-like diffeomorphism of a closed orientable surface $M^2$ there exist a gradient-like flow and a periodic diffeomorphism of this surface such that the original diffeomorphism is a superposition of a diffeomorphism that is a shift per unit time of the flow and the periodic diffeomorphism. In the case when $M^2$ is a two-dimensional torus, there is a topological classification of periodic maps. Moreover, it is known that there is only a finite number of topological conjugacy classes of periodic diffeomorphisms that are not homotopic to identity one. Each such class contains a representative that is a periodic algebraic automorphism of a two-dimensional torus. Periodic automorphisms of a two-dimensional torus are not structurally stable maps, and, in general, it is impossible to predict the dynamics of their arbitrarily small perturbations. However, in the case when a periodic diffeomorphism is algebraic, we constructed a one-parameter family of maps consisting of the initial periodic algebraic automorphism at zero parameter value and gradient-like diffeomorphisms of a twodimensional torus for all non-zero parameter values. Each diffeomorphism of the constructed one-parameter families inherits, in a certain sense, the dynamics of a periodic algebraic automorphism being perturbed.
Key Words: two-dimensional torus, nonhyperbolic algebraic automorphism, one-parameter families
For citation: V. Z. Grines, D. I. Mints, E. E. Chilina. On perturbations of algebraic periodic automorphisms of a two-dimensional torus. Zhurnal Srednevolzhskogo matematicheskogo obshchestva. 24:2(2022), 141–150. DOI: https://doi.org/10.15507/2079-6900.24.202202.141-150
Submitted: 30.03.2021; Revised: 02.05.2022; Accepted: 25.05.2022
Information about the authors:
Vyacheslav Z. Grines, Professor of the Department of Fundamental Mathematics, National Research University «Higher School of Economics» (25/12 Bolshaya Pecherskaya St., Nizhny Novgorod 603150, Russia), Dr.Sci. (Phys.-Math.), ORCID: https://orcid.org/0000-0003-4709-6858, [email protected]
Dmitrii I. Mints, Research Assistant, International Laboratory of Dynamical Systems and Applications, National Research University «Higher School of Economics» (25/12 Bolshaya Pecherskaya St., Nizhny Novgorod 603155, Russia), ORCID: https://orcid.org/0000-0003-0329-6946, [email protected]
Ekaterina E. Chilina, Research Assistant, International Laboratory of Dynamical Systems and Applications, National Research University «Higher School of Economics» (25/12 Bolshaya Pecherskaya St., Nizhny Novgorod 603155, Russia), ORCID: https://orcid.org/0000-0002-1298-9237, [email protected]
All authors have read and approved the final manuscript.
Conflict of interest: The authors declare no conflict of interest.
This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License.
| 2022-08-09T02:04:20 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5938335657119751, "perplexity": 3534.501307020342}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882570879.37/warc/CC-MAIN-20220809003642-20220809033642-00153.warc.gz"}
|
https://survivor.togaware.com/datascience/enhanced-plots-draw-branches-as-dotted-lines.html
|
## 20.60 Enhanced Plots: Draw Branches as Dotted Lines
prp(model, type=2, extra=106, nn=TRUE, fallen.leaves=TRUE,
branch.lty=3)
The branch.lty= option allows us to specify the type of line to draw for the branches. A dotted line is attractive as it reduces the dominance of the branches whilst retaining the node connections. Other options are just the standard values for line type in R:
% Following came from % http://students.washington.edu/mclarkso/documents/line%20styles%20Ver2.pdf Give credit in Further Reading section of Plots.Rnw
The line type can also be specified as an even length string of up eight characters of the hex digits (0–9, a–f). The pairs specify the length in pixels of the line and the blank. Thus lty=“44” is the same as lty=2:
plot(c(0,1), c(0,0), type="l", axes=FALSE, xlab=NA, ylab=NA, lty=2)
plot(c(0,1), c(0,0), type="l", axes=FALSE, xlab=NA, ylab=NA, lty="dashed")
plot(c(0,1), c(0,0), type="l", axes=FALSE, xlab=NA, ylab=NA, lty="44")
Your donation will support ongoing development and give you access to the PDF version of this book. Desktop Survival Guides include Data Science, GNU/Linux, and MLHub. Books available on Amazon include Data Mining with Rattle and Essentials of Data Science. Popular open source software includes rattle, wajig, and mlhub. Hosted by Togaware, a pioneer of free and open source software since 1984.
Copyright © 1995-2021 [email protected] Creative Commons Attribution-ShareAlike 4.0.
| 2021-09-19T16:47:02 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.1705760806798935, "perplexity": 7746.2648087205125}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780056892.13/warc/CC-MAIN-20210919160038-20210919190038-00177.warc.gz"}
|
https://nroer.gov.in/55ab34ff81fccb4f1d806025/file/58dd4558472d4a03227bfb6b
|
### Special Integrals 02:
This is the second part of Integral calculus. In this video, we will learn how can an integral be reduced to another special integral.
| 2020-07-10T21:50:03 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9220563769340515, "perplexity": 606.1925230561202}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593655912255.54/warc/CC-MAIN-20200710210528-20200711000528-00496.warc.gz"}
|
https://indico.bnl.gov/event/10080/?print=1
|
High Energy / Nuclear Theory / RIKEN seminars
# [NT/RIKEN seminar] Relativistic Navier-Stokes equations
## by Pavel Kovtun (University of Victoria)
US/Eastern
Description
It has been widely believed that the relativistic Navier-Stokes equations violate the basic physical requirements of equilibrium stability and causality, and therefore can not be used for practical simulations of relativistic fluids. In this talk, I will discuss why this belief is unfounded. There is not one, but infinitely many Navier-Stokes equations because there are infinitely many conventions that can be used to define what one means by "fluid temperature", "fluid velocity" etc. out of equilibrium. The early works on relativistic hydrodynamics (Eckart, Landau-Lifshitz) have indeed adopted conventions that lead to unphysical predictions. On the other hand, when one adopts physically sensible conventions, the resulting relativistic Navier-Stokes equations are both stable and causal.
| 2021-09-26T00:52:44 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8530049324035645, "perplexity": 1124.1508166229316}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780057787.63/warc/CC-MAIN-20210925232725-20210926022725-00148.warc.gz"}
|
https://publications.drdo.gov.in/ojs/index.php/dsj/article/download/1340/4649
|
Hypersonic Intake Starting Characteristics–A CFD Validation Study
Numerical simulation of hypersonic intake starting characteristics is presented. Three dimensional RANS equations are solved alongwith SST turbulence model using commercial computational fluid dynamics (CFD) software. Wall pressure distribution and intake performance parameters are found to match well with experimental data for different free stream Mach number in the range of 3-8. The unstarting of the intake is traced from the sudden drop of mass capture ratio. Wall condition (adiabatic or isothermal) is seen to have pronounced effect in estimating the performance parameters in the intake. The computed unstarting Mach number is seen to be higher for adiabatic condition compared to isothermal condition. For unstarting case, large separation bubble is seen near the entrance of the intake, which is responsible for expulsion of the shock system out of the intake.
The performance of a ramjet/scramjet powered hypersonic vehicle is determined by its inlet efficiency as the engine depends very much on the quantity and quality (uniformity and total pressure) of the flow required for its smooth performance. Hypersonic intakes are designed as mixed compression intake which is a combination of internal and external compression. A schematic of the flow pattern in the mixed compression intake is shown in Fig 1. The bow shock of the vehicle forebody compresses the air followed by the number of compression at the central body which coalesces at the cowl lip at design Mach number. The flow is turned inward to the axial direction in the internal compression zone by the lip geometry. The interaction of the reflected shock with the existing boundary layer on the ramp surface might lead to formation of a separation zone. The extent of separation will depend on the strength of the reflected shock and the condition of the boundary layer on the ramp surface.
Figure 1. Schematic of the flow field in the mixed compression intake
One major problem of hypersonic intakes with internal compression is the ‘unstart problem’ which describes the phenomenon that supersonic internal flow is not reached in the internal compression region if the area ratio between the throat and capture area is too low when the flight Mach number is increased. The internal flow remains subcritical and the intake is chocked. Generally unstart of the intake is observed through expulsion of the shock system and massive spillage, leading to degraded pressure recovery and large flow distortion at the exit and hence there may be catastrophic effect in the vehicle performance. The unstart of the intake could occur due to several reasons, e.g. over-contraction, variation of flight conditions, perturbations in combustor operation, back pressure, angle of attack, etc., or due to a combined effect of these factors. Interaction of the boundary layer with shock reflections and subsequent thickening of the boundary layer inside the internal duct, are believed to be the prime cause of a separation leading to a complex oscillatory flow structure and expulsion of the shock and the unstart of the intake. Usually, to start supersonic inlets at any flight condition, variable intake geometry or bleed bypass is used. But in a hypersonic flow situation which contains high enthalpy flow with high total temperature (~1800 K), any complex mechanical control system may cause severe structural and cooling problems.
The prediction of intake unstart and the mitigation plan to reduce its occurrence or its effect is very much essential for hypersonic intake design. Experimental and numerical research is in progress to understand the causes of hypersonic intake unstart and means to avoid it. Schmitz and Bissinger1. studied experimentally two fixed geometry hypersonic intakes and reported starting of the intake at M = 4.3 and stable operation up to M = 6. Various performance parameters of two geometries were also compared. Schneider and Koschel2. studied both experimentally and numerically the start and throttling behavior of a supersonic intake system of 9 different configurations with geometric variation at different inlet Mach number and exit throttling conditions. It was shown that by proper geometry selection, the size of the separation bubble at the ramp surface could be minimized without applying boundary layer bleed and high intake performance could be achieved. Goonko, et al. 3 reported experimental studies of three dimensional inlet at Mach number range 4 to 8 with ramp and side-swept compression wedges and depicted complex system of multiple shock waves, expansion waves and vortex structures leading to significant nonuniformity of the flow field at the inlet entrance and exit.
Haberle and Gulhan45 studied experimentally the effect of different bleed dimension and internal contraction ratios on starting characteristics of 2-D and 3-D scramjet inlets at hypersonic Mach number. Das and Prasad6. have conducted both experimental and numerical investigation of mixed compression intake flow field at Mach 2.2 with different cowl deflections and showed that small angle at the cowl lip leads to start of the intake and improve its performance. Experimental and numerical studies of Dirk, et al.7demonstrate that bleed can reduce boundary layer separation and improve the inlet total pressure recovery. Molder, et al 8 have studied the effect of mass extraction and overboard spillage as a means to start the intake and defined a starting index based on this study. They have also shown that for M>4, the starting operation regime can be increased by mass extraction. Reinhold, et al9 studied a multiple strut based 2-D hypersonic ramjet inlet flowfield using a Parabolised Navier Stokes code and presented good comparison of simulation results against experiment. Lind, et al 10 have studied the effect of forebody shock and cowl lip shock interaction demonstrating that, the shock-shock interaction can lead to very high pressure and temperature region around the cowl lip resulting in flow instability. It was observed that free stream variations have strong influence in making the flow unsteady. Brenneis, et al. 11. have studied 2-D inlet at freestream Mach number 7.4 and shown that there is drastic change in the behavior of the flowfield with adiabatic wall compared to fixed temperature wall. Barber, et al. 12. have carried out intercode comparisons to predict the starting characteristics of hypersonic intakes. It has been shown that starting characteristics is strongly dependent on viscous flow effects and choice of turbulence model has significant impact on the prediction of shock wave boundary layer interaction (SWBLI). Predicted transient calculations exhibit a time-lag effect related to SWBLI effects. Donde, et al 13. carried out numerical simulations of a starting problem in a variable geometry hypersonic intake with a movable cowl. Dynamic meshes have been used for depicting motion of the cowl. It was shown that the cowl needs to be rotated through 15.7° and then be brought back to the original position for restarting of the intake after an ‘unstart’. Yu, et al. 14. studied hypersonic inlet numerically for different freestream conditions and the backpressure using a RANS code with RNG k-ε turbulence model. A new method of pattern classification of inlet start/unstart is developed using the ‘numerical/experimental’ database by the support vector machine-recursive feature elimination algorithm. The control can sense inlet start/unstart through this pattern classification data. In order to develop these databases numerical tools played an important tool.
It is clear from the above discussion that the problem of starting of hypersonic intake has not been fully understood and requires further investigation. In this work, starting problem of hypersonic air-intake pertaining to experimental condition of Emami and Trexler 15 is simulated by solving 3-D RANS equations alongwith SST turbulence model using a commercial code 16. The computed results were compared with experimental values and insights were obtained about the complex process through analysis of various flow variables.
Figure 2 presents the intake geometry of Emami and Trexler 16. alongwith dimensions. In the geometry, the x-axis is taken along the longitudinal direction, while y and z axes are taken along the height and width of the model respectively. The intake is a 2-D geometry with ramp in the lower surface, which makes an angle of 11 degrees to the x-axis. The cowl is attached to the upper surface, and is tilted downwards by 3 degrees about x-axis. The throat height (h) is 0.01 m. All other dimensional details are provided in Fig 2. Side fencing of the intake starts ahead of the cowl lip. It is provided to prevent the flow compressed by ramp from spilling sidewise into ambient. 3-D computational domain is created to account for the simulation which is shown in Fig 3 along with all the boundaries and is extended upto a length of 0.34m in the longitudinal direction.
Figure 2. Air intake geometry of Emami and Trexler 16 for which the simulations are carried out.
Figure 3.computational domain alongwith their boundaries.
Since the intake is symmetric about mid-plane, the computational domain upto half of the intake width (25.4 mm) is simulated. Hexahedral grids of sizes 0.4 million (coarse grid) and 0.68 million (fine grid) are generated for grid variation study. In the forebody and in the intake interior, the number of cells in X,Y and Z directions are 338X49X30 and 259X32X30 for fine and coarse grid respectively. The grids are made very fine near the intake entry and near the throat for capturing the flow crisply. The axial distribution of Y+ along the length of the lower surface is presented in Fig. 4. In most of the length Y+ is less than 20; although in the downstream of the throat Y+ value is about 40. The minimum distance at the first cell is kept 0.05 mm and the sizes were exponentially stretched along the height. There are 5 to 10 cells in boundary layers at different regions.
Figure 4.y+ distribution along the lower surface of the intake.
3-D Reynolds averaged unsteady Navier stokes equations with SST turbulence model are solved. A density based solver with 2nd order spatially accurate Roe-Flux difference splitting scheme 17. is used for spatial discretisation and 2nd order implicit Euler Scheme for temporal discretisation is used in the present solution.
3.1 Governing Equation
The appropriate system of equations governed the turbulent compressible gas may be written as
Continuity equation:
$\frac{\partial \rho }{\mathrm{\partial t}}+\frac{\partial }{\partial {\chi }_{\kappa }}\left(\rho {\mu }_{\kappa }\right)=0$ k = 1,2,3
Momentum equation :
$\frac{\partial }{\partial t}\left(\rho {u}_{i}\right)+\frac{\partial }{\partial {x}_{\mathit{\kappa }}}\left(\rho {u}_{i}{u}_{k}\right)+\frac{\partial \rho }{\partial {x}_{\mathrm{i}}}=\frac{\partial \left({\mathit{\tau }}_{\mathrm{ik}}\right)}{\partial {x}_{\mathrm{i}}}$ ,i,k =1,2,3
Energy equation :
$\frac{\mathit{\partial }}{\mathit{\partial }t}\mathit{\left(}\mathit{\rho }E\mathit{\right)}\mathit{+}\frac{\mathit{\partial }}{\mathit{\partial }{x}_{k}}\mathit{\left(}\mathit{\rho }{u}_{k}H\mathit{\right)}\mathit{=}\mathit{-}\frac{\mathit{\partial }}{\mathit{\partial }{x}_{k}}\mathit{\left(}{u}_{j}{\mathit{\tau }}_{\mathrm{jk}}\mathit{\right)}\mathit{+}\frac{\mathit{\partial }{q}_{k}}{\mathit{\partial }{x}_{k}}$ ,
j,k = 1,2,3
where, ρ,u i,p, E and Hare the density, velocity components, pressure and total energy and enthalpy respectively Turbulent shear stress is defined as
μ= μl + μt is the total viscosity; μl , μt being the laminar and turbulent viscosity
Laminar viscosity (μl ) is calculated from Sutherland law as
${\mu }_{\iota }={\mu }_{\mathrm{ref}}{\left(\frac{\mathrm{T}}{{\mathrm{T}}_{\mathrm{ref}}}\right)}^{3}{2}}\left(\frac{{\mathrm{T}}_{\mathrm{ref}}}{+}\right)$
where, T is the temperature and μref , Tref and S are known coefficient.
In eddy viscosity models, the stress tensor is expressed as a function of turbulent viscosity (μt ). Based on dimensional analysis, few variables (k, ε, ω) are defined as given below,
Turbulent kinetic energy k,
$\mathrm{k}=\overline{{{\mathrm{u}}_{\mathrm{i}}}^{\prime }{{\mathrm{u}}_{\mathrm{i}}}^{\prime }}/2$
Turbulent dissipation rate ε,
$\mathit{ϵ}\mathit{\equiv }\mathit{\nu }\overline{\frac{\mathit{\partial }{{u}_{i}}^{\mathit{\prime }}}{\mathit{\partial }{x}_{j}}\left(\frac{\mathit{\partial }{u}_{i}}{\mathit{\partial }{u}_{j}},+,\frac{{{\mathit{\partial }u}^{\mathit{\prime }}}_{j}}{{\mathit{\partial }x}_{i}}\right)}$
Specific dissipation rate ω,
ω = ε /k
The turbulent viscosity μt is calculated as
${\mathit{\mu }}_{t}\mathit{=}{c}_{\mathit{\mu }}\frac{\mathit{\rho }{k}^{\mathit{2}}}{\mathit{ϵ}}$
The heat flux qk is calculated as ${q}_{k}\mathit{}\mathit{=}\mathit{-}\mathit{\lambda }\frac{\mathit{\partial }T}{\mathit{\partial }{x}_{k}}$, λ is the thermal conductivity
3.2 k-ω Turbulence Model
The turbulent viscosity is calculated as function of k and ω 18
${\mu }_{\mathrm{t}}=\mathrm{f}\left(\frac{{\rho }^{\mathrm{k}}}{\omega }\right)$
Turbulent kinetic energy (k) equation:
$\frac{\partial }{\partial \mathrm{t}}\left(\rho \mathrm{k}\right)+\frac{\partial }{\partial {\mathrm{x}}_{\mathrm{i}}}\left(\rho \mathrm{k}{\mathrm{u}}_{\mathrm{i}}\right)=\frac{\partial }{\partial {\mathrm{x}}_{\mathrm{j}}}\left({\Gamma }_{\mathrm{k}}\frac{\partial \mathrm{k}}{\partial {\mathrm{x}}_{\mathrm{j}}}\right)+{\mathrm{G}}_{\mathrm{k}}-{\mathrm{Y}}_{\mathrm{k}}$ (2.4.13)
Specific dissipation rate (ω) equation:
$\frac{\mathit{\partial }}{\mathit{\partial }t}\mathit{\left(}\mathit{\rho }\mathit{\omega }\mathit{\right)}\mathit{+}\frac{\mathit{\partial }}{\mathit{\partial }{x}_{i}}\mathit{\left(}\mathit{\rho }\mathit{\omega }{u}_{i}\mathit{\right)}\mathit{=}\frac{\mathit{\partial }}{\mathit{\partial }{x}_{j}}\left({\mathit{\Gamma }}_{\mathit{\omega }}\frac{\mathit{\partial }\mathit{\omega }}{\mathit{\partial }{x}_{j}}\right)\mathit{+}{G}_{\mathit{\omega }}\mathit{-}{Y}_{\mathit{\omega }}$
where are the production, dissipation and diffusion terms of the k and ω equations respectively
3.3 SST Turbulence Model
To retain the robust and accurate formulation of Wilcox’s k-ω model in the near wall region, and to take advantage of the freestream independence of the k-ε model in the outerpart of the boundary layer, Menter 19. blended both the models through a switching function. k-ε model was transformed into Wilcox’s k-ω formulation and was multiplied by (1–F 1) and added to original k-ω model multiplied by F1. The blending function F1will be one in the near wall region and zero away from the surface.
In the second step, the definition of eddy viscosity was modified in the following way to account for the transport of the principal turbulent shear stress ($\mathit{\tau }\mathit{}\mathit{=}\mathit{\text{}}\overline{\mathit{-}\mathit{\rho }{u}^{\mathit{\prime }}{v}^{\mathit{\prime }}}$ )
${\nu }_{\mathrm{t}}=\frac{{a}_{\mathit{1}}k}{\mathrm{max}\left({\mathrm{a}}_{1}\omega ;\Omega {\mathrm{F}}_{2}\right)}$
3.4 Boundary Condition
At the inlet of the intake, freestream static pressure and total temperature (T0) condition is imposed. By varying the inlet total pressure (P0), different free stream Mach numbers have been simulated. At the intake exit boundary, supersonic outflow boundary condition has been employed. For the ambient outlet also, the supersonic outflow condition is imposed. Adiabatic, no slip wall condition has been imposed for top, bottom, side and cowl walls. To find the effect of wall temperature on intake performance, simulations were also performed with 300K temperatures on the wall. All simulations is performed at zero angle of attack.
4.1 Steady State Simulation for Inlet with Free Stream Mach number 4
Figure 5 shows Mach number distribution in the intake mid plane for free stream Mach number 4 and zero angle of attack. Zoomed view of Mach number around intake cowl lip is also shown in the figure. It can be seen that oblique shock generated from the lower ramp is above the cowl lip indicating flow spillage. The shock from cowl lip impinges inside the intake on the ramp surface. Further, the cowl shock gets reflected from both the ramp and upper wall multiple times to create a train of oblique shocks inside the intake which further compresses the flow. The axial distribution of lower ramp wall pressure are compared with experimental data 15. in Fig. 6. The pressure and distances are nondimensionalised with free stream pressure (pinf) and intake throat height (h) respectively. Though, in general a good agreement is obtained between prediction and experiment, there is a difference in the position of the cowl shock impingement point. The effect of grid on the results is studied by computing the flow on fine grid. The comparison of ramp pressure distribution for both the grids is also plotted in Fig. 6.
Figure 5. Mach number plot for inlet entry Mach 4.
Figure 6.Comparison of lower ramp wall pressure for two grids at Mach 4.
Though, there is no significant change in pressure distribution up to x = 0.28 m, the pressure peaks have become sharper with fine grid. Beyond x = 0.28m, shock reflections were captured more crisply in the fine grid. The difference in surface pressure between the experimental and numerical values near x/h=20 is due to the inability of the turbulence model to predict the pressure ahead of the separation bubble. Incorporation of unsteady correction term is suggested 20. in recent literature to improve the prediction. Recent version of k-ω model21. has also shown improved performance in predicting the high speed flow. However, in the present study, SST turbulence model in its original form is used. The velocity vector plot inside the intake is shown in Fig. 7 where two shock induced separation bubbles are seen. To locate the starting of separation bubble, the axial wall shear stress distribution is presented in Fig. 8. The wall shear stress is seen to be nearly zero at x/h= 22.6 and 26.8 indicating the location of separation bubble inside the intake.
Figure 7. Streamline plot in air intake showing flow separation colored with flow velocity in m/s.
Figure 8. Axial distribution of wall shear inside the intake.
4.2 Simulation for different Free Stream Inlet Mach Number–unstarting of Intake
In order to bring out the condition at which the intake unstarting occurs, steady state simulations were also carried out for Mach 8, 7, 6, 5, 4, 3.5, 3.3, 3.2 and 3 conditions respectively by varying the total pressure at inlet. Initially, all the simulations were carried out under adiabatic wall condition. As the test duration is very short 15., it is expected that wall temperature will not change much during test duration. Hence,
simulations with wall temperature 300 K were also carried out. For determining the unstart condition of the intake, simulations are done first at a higher Mach number at which the intake starts and the Mach number is then gradually reduced to lower values. The converged solution corresponding to higher Mach number is fed as the initial flow field values for lower inlet free stream Mach numbers. Computed values of Mass capture ratio and mass averaged total pressure ratios for different free stream Mach numbers for adiabatic and isothermal wall conditions are compared with experimental results in Figs 9 and 10 respectively.
Figure 9.Comparison of mass capture ratio for different free stream Mach numbers.
Figure 10.Comparison of total pressure recovery for different free stream Mach numbers.
It is observed that for computed values of mass flow ratios and pressure recoveries match well with the isothermal calculation, while adiabatic wall condition shows a lower value. The difference in intake performance due to change in wall temperature has also been reported by Brenneis, et al. 11It is observed that there is sudden drop in mass capture ratio and total pressure recovery around Mach number 3 whereas this drop is observed at Mach number 4 for adiabatic wall condition. This drop in values can be considered as the unstarting of the intake. The drop in mass capture ratiois happening because of strong flow separation due to shock-boundary layer interaction which is responsible for most of the flow spillage. For adiabatic wall condition the flow spillage is more compared to isothermal wall condition. This fact will be evident from the comparison of Mach number distribution at symmetry plane for adiabatic and isothermal case for M∞=3.5 in Fig 11. Large separation bubble near the intake entrance for the adiabatic case is responsible for expulsion of shock system outside the intake and causing the intake to unstart. It can be noticed that in adiabatic case, an oblique shock is generated ahead of flow separation in the cowl entry. This causes a large flow spillage and drop in mass capture. No separation bubble is seen for the isothermal case. The higher gas temperature for adiabatic wall, (900 K, the recovery temperature) reduces density and momentum of flow; whereas for isothermal wall condition, the boundary layer flow is relatively at a lower temperature causing higher momentum. As a result, for adiabatic wall condition the boundary layer flow is expected to separate at a higher Mach number because of lower momentum compared to isothermal wall condition.
Starting characteristics of a 2-D hypersonic intake with side fencing is presented. 3-D RANS equations are solved with SST turbulence model using commercial CFD software. The steady state simulations have been done for different Mach numbers ranging from 3.0 to 8.0 for both adiabatic and isothermal wall condition (Tw = 300K). Computed wall pressure distribution and intake performance parameters (mass flow ratio and total pressure recovery) match reasonably well with experimental results. The free stream Mach number for which intake unstarting occurs is found out from the sudden drop in the mass capture ratio. It is observed that wall boundary condition for temperature (adiabatic or isothermal) has a pronounced effect in determining the starting Mach number. Computed free stream Mach number for which unstarting occur is higher for adiabatic condition compared to isothermal condition. Heated boundary layer for adiabatic condition is seen to cause large separation bubble at the intake entrance causing flow unstarting; while flow separation bubble is not observed for isothermal condition for same free stream Mach number.
1. Schmitz, D.M. Bissinger, N.C. Design and testing of 2-D fixed –Geometry hypersonic intakes. AIAA Paper No. 98-1529, 1998.
2. Schneider, A. Koschel, W.W. Detailed analysis of a mixed compression hypersonic intake. ISABE Paper No. 99-7036, 1999.
3. Goonko, Y.P.; Latypov, A.F.; Mazhul, I.I.; Khartinov, A.M.; Yaroslavtsev, & Rostland, P. Structure of flow over a hypersonic inlet with side compression wedges. AIAA Journal, 2003, 41(3), 436-47
4. Haberle, J. & Gulhan, A., Experimental investigation of a two-dimensional and three dimensional scramjet inlet at Mach 7. J. Propulsion Power, 2008, 24(5), 1023-034.
5. Hebrale, J. & Gulhan, A. Internal flowfield investigation of hypersonic inlet at Mach 6 with bleed. J. Propulsion Power, 2007, 23(5), 1007-017.
6. Das, S. & Prasad J.K. Starting characteristics of a rectangular supersonic airintake with cowl deflection. Aeronautical Journal, 2010, 114(3), 177-89.
7. Dirk, S.; Andreas, H. & Ulrich, W. Reduction of shock induced boundary layer separation in hypersonic inlets using bleed. Aerospace Sci. Technol., 1998, 2(4), 231-39.
8. Molder, S.; Timofeev, E.V. Tahir, R.B. Flow starting in high compression hypersonic air inlets by mass spillage.AIAA Paper No. 2004-4130, 2004.
9. Reinhold, A.; Gerbsch & Agarwal, Ramesh K. Computation of hypersonic ramjet-inlet flowfields using an upwind parabolized Navier-Stokes code. AIAA Paper No. 88-2828, 1988.
10. Lind, C.A. & Lewis, M.J. The effect of shock/shock interactions on the design of hypersonic inlets. AlAA Paper No. 90-2217, 1990.
11. Brenneis, A. & Wanie, K.M. Navier-Stokes results for hypersonic inlet flows. AlAA Paper No. 91-2472, 1991.
12. Barber, T.J.; Hiett, D. & Fastenberg, S. CFD modeling of the hypersonic inlet starting problem. AIAA Paper No. 2006-0123, 2006.
13. Donde, P.; Marathe, A.G. & Sudhakar, K. Starting in hypersonic intakes. AIAA Paper No. 2006-4510.
14. Yu, D.; Chang, J.; Bao, W. & Zong, X. Optimal classification criterions of hypersonic inlet start/unstart. J. Propulsion Power, 2007, 23(2), 310-16.
15. Emami, S. & Trexler, C. A. Experimental investigation of inlet combustor – isolators for a dual mode scramjet at a Mach number of 4. NASA Technical Report No. NASA TP3502, May 1995.
16. Fluent 6.3 User’s guide, 2006, Fluent Inc, USA
17. Roe, P.L. Characteristic based schemes for the Euler equations. Ann. Rev. Fluid Mechanics, 1986, 18, 337-65.
18. Wilcox, D.C. Multiscale model for turbulent flows. AIAA Journal, 1988, 26(11), 1311-320.
19. Menter, F.R. Performance of popular turbulence models for attached and separated adverse pressure gradient flows. AIAA Journal, 1992, 30(8), 2066-072.
20. Pasha, A.A. & Sinha, K. Simulation of hypersonic shock/turbulent boundary-layer interactions using shock-unsteadiness model. J. Propulsion Power, 2012, 28(1), 46-60.
21. Wilcox, D.C. Formulation of the k −ω turbulence model revisited. AIAA Paper No. 2007-1408.
Mr Soumyajit Saha obtained his ME (Aerospace Engg) from Indian Institute of Science (IISc), Bengaluru. Presently, he is working as Scientist E in Directorate of Computational Dynamics, Defence Research & Development Laboratory (DRDL), Hyderabad. His research interests include: CFD, aerodynamics, high-speed combustion, and propulsion. He has 5 journal and 4 conference publications to his credit.. Dr Debasis Chakraborty obtained his PhD in Aerospace Engineering from IISc, Bengaluru. Presently, he is working as Technology Director, Computational Dynamics Directorate, DRDL, Hyderabad. His research interests are : CFD, aerodynamics, high-speed combustion, and propulsion. He has about 40 journal and 50 conference publications to his credit.
| 2022-01-23T05:34:49 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 13, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6203954815864563, "perplexity": 2931.1533129749855}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304134.13/warc/CC-MAIN-20220123045449-20220123075449-00676.warc.gz"}
|
https://news.fnal.gov/events/event/virtual-meeting-only-neutrino-seminar-series-cp-violation-at-lbn-experiments/
|
## Virtual Meeting Only – Neutrino Seminar Series: CP Violation at LBN Experiments
• Oct. 22, 2020, 1:00 pm
This week we are pleased to have Peter Denton from Brookhaven National Laboratory, who will talk about CP Violation at Long-Baseline Neutrino Experiments.
Please join us on Thursday October 22nd at 1 PM Central Time. Zoom connection details and instructions are below. For the smooth running of the seminar we would appreciate if you reviewed the guidelines. We note that the zoom meeting is now password protected and this password is given in the zoom details below.
Title: “CP Violation at Long-Baseline Neutrino Experiments”
Abstract:
The nature of CP violation in the lepton sector is one of the biggest open questions in particle physics. Long-baseline accelerator experiments have the opportunity to determine if CP is violated in the mass matrix. I will discuss some theoretical issues about how CP is parameterized and, in particular, that using $\delta$ is misleading. Then I will look at the most recent NOvA and T2K data which show a slight and very interesting tension. While this tension possibly indicates a flipping in the mass ordering, it is better fit by new physics such as NSI with an additional source of CP violation. The strength of this NSI can be easily estimated analytically and I will present a numerical analysis of the preferred regions which are generally consistent with other constraints.
| 2020-12-05T12:40:07 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.641437828540802, "perplexity": 1402.2049697483042}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141747774.97/warc/CC-MAIN-20201205104937-20201205134937-00670.warc.gz"}
|
https://control.com/textbook/signal-characterization/
|
# Chapter 26 - Signal Characterization in Control Systems
## Chapter 26 - Signal Characterization in Control Systems
Mathematics is full of complementary principles and symmetry. Perhaps nowhere is this more evident than with inverse functions: functions that “un-do” one another when put together. A few examples of inverse functions are shown in the following table:
$f(x)$ $f^{-1}(x)$
Multiplication Division
Power Root
Exponential Logarithm
Derivative Integral
Inverse functions are vital to master if one hopes to be able to manipulate algebraic (literal) expressions. For example, to solve for time ($$t$$) in this exponential formula, you must know that the natural logarithm function directly “un-does” the exponential $$e^x$$. This is the only way to “unravel” the equation and get $$t$$ isolated by itself on one side of the equals sign:
$V = 12e^{-t}$
$\hbox\textit{Divide both sides by 12}$
${V \over 12} = e^{-t}$
$\hbox\textit{Take the natural logarithm of both sides}$
$\ln \left({V \over 12}\right) = \ln \left(e^{-t}\right)$
$\hbox\textit{The natural logarithm cancels out'' the exponential}$
$\ln \left({V \over 12}\right) = -t$
$\hbox\textit{Multiply both sides by negative one}$
$- \ln \left({V \over 12}\right) = t$
In industry there exist a great many practical problems where inverse functions play a similar role. Just as inverse functions are useful for manipulating literal expressions in algebra, they are also useful in inferring measurements of things we cannot directly measure. Many continuous industrial measurements are inferential in nature, meaning that we actually measure some other variable in order to quantify the variable of interest. More often than not, the relationship between the primary variable and the inferred variable is nonlinear, necessitating some form of mathematical processing to complete the inferential measurement.
Practical examples of inferential measurement include:
• Liquid flow measurement through restrictions in pipes
• Liquid flow measurement in open channels (over weirs)
• Liquid level measurement in non-cylindrical vessels
• Temperature measurement by radiated energy
• Chemical composition measurement
The following sections will describe the mathematics behind each of these measurement applications.
Published under the terms and conditions of the Creative Commons Attribution 4.0 International Public License
| 2022-01-21T04:41:08 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.31685343384742737, "perplexity": 1200.656098603142}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320302723.60/warc/CC-MAIN-20220121040956-20220121070956-00393.warc.gz"}
|
http://dlmf.nist.gov/15.2
|
# §15.2 Definitions and Analytical Properties
## §15.2(i) Gauss Series
The hypergeometric function is defined by the Gauss series
on the disk , and by analytic continuation elsewhere. In general, does not exist when . The branch obtained by introducing a cut from 1 to on the real -axis, that is, the branch in the sector , is the principal branch (or principal value) of .
For all values of
again with analytic continuation for other values of , and with the principal branch defined in a similar way.
Except where indicated otherwise principal branches of and are assumed throughout the DLMF.
The difference between the principal branches on the two sides of the branch cut (§4.2(i)) is given by
On the circle of convergence, , the Gauss series:
• (a)
Converges absolutely when .
• (b)
Converges conditionally when and is excluded.
• (c)
Diverges when .
## §15.2(ii) Analytic Properties
The principal branch of is an entire function of , , and . The same is true of other branches, provided that , 1, and are excluded. As a multivalued function of , is analytic everywhere except for possible branch points at , 1, and . The same properties hold for , except that as a function of , in general has poles at .
Because of the analytic properties with respect to , , and , it is usually legitimate to take limits in formulas involving functions that are undefined for certain values of the parameters.
For example, when , , and , is a polynomial:
This formula is also valid when , , provided that we use the interpretation
and not
which is sometimes used in the literature. (Both interpretations give solutions of the hypergeometric differential equation (15.10.1), as does , which is analytic at .) For illustration see Figures 15.3.6 and 15.3.7.
In the case the right-hand side of (15.2.4) becomes the first terms of the Maclaurin series for .
| 2013-05-23T12:43:48 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9810620546340942, "perplexity": 772.6427488801279}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368703306113/warc/CC-MAIN-20130516112146-00075-ip-10-60-113-184.ec2.internal.warc.gz"}
|
https://fermi.gsfc.nasa.gov/ssc/data/analysis/gbm/gbm_data_tools/gdt-docs/notebooks/PositionHistory.html
|
# The Position History Data¶
Probably the most critical auxiliary file GBM produces is the position history (POSHIST) file. The POSHIST contains, for an entire day, the spacecraft location in orbit and pointing information, sampled on a 1 second timescale. If you are just interested in triggered GRB analysis where all of the response files are already made for you, then POSHIST may not be of much interest. But if you are using the continuous data in any way, the POSHIST is your dearest friend. You may want to know if a source is visible at a particular time (i.e. not behind the Earth), and if it is, what is the closest detector to the source. You may want to know if there are specific contributions to the background during a time interval, such as sun visibility or high geomagnetic latitude in orbit. You may want to rotate something from the equatorial frame to the Fermi inertial frame, or vice versa. Or you may want to make a pretty gif of the detector pointings over time.
[1]:
from gbm import test_data_dir
from gbm.data import PosHist
# open a poshist file
poshist = PosHist.open(test_data_dir+'/glg_poshist_all_170101_v00.fit')
print(poshist)
glg_poshist_all_170101_v00.fit
An important thing you should check is the time coverage of the POSHIST to ensure it is the file you need. The times are listed in Fermi Mission Elapsed Time (MET).
[2]:
poshist.time_range
[2]:
(504921540.740104, 505008061.340078)
This seems like a good time for a brief aside about MET and time conversions. Sometimes you don’t know the MET corresponding to the time you’re interested in, or you’re not sure what a given MET really means. There is a nice utility class in gbm.time that will allow you to do various time coversions to/from MET. Let’s see what poshist time_range is in UTC:
[3]:
from gbm.time import Met
[Met(t).iso() for t in poshist.time_range]
[3]:
['2016-12-31T23:58:56', '2017-01-02T00:00:56']
Similarly, you can use the Met class to go from some time convention or epoch to MET. This is useful because many of the functions and classes in the Data Tools use the MET:
[4]:
met = Met.from_iso('2017-01-01T14:58:15')
met.met
[4]:
504975500.0
Ok, back to the position history!
The POSHIST also contains information about good time intervals (GTI). GTIs are intervals when the GBM detectors were operational and observing. Mostly non-operational times are when Fermi is passing through the South Atlantic Anomaly (SAA). The listing of GTIs in the POSHIST is an attribute:
[5]:
poshist.gti
[5]:
[(504921540.740104, 504924818.340072),
(504925227.340079, 504962247.340076),
(504963081.340078, 504967992.340078),
(504969383.340077, 504973833.340077),
(504975419.340078, 504979728.340076),
(504981395.340078, 504985767.340077),
(504987345.340078, 504991938.340124),
(504993281.340069, 504998034.340079),
(504999211.340076, 505004088.340077),
(505005126.34007, 505008061.340078)]
Let’s say we are interested in data around a specific time, for example MET=504975500. We can query the PosHist object for various things, such as where Fermi was in orbit at that particular time:
[6]:
t0 = 504975500.0
lat = poshist.get_latitude(t0)
lon = poshist.get_longitude(t0) # note: East longitude
alt = poshist.get_altitude(t0) # in meters
print('Latitude: {:.2f}'.format(lat))
print('Longitude: {:.2f}'.format(lon))
print('Altitude: {:.2f} m'.format(alt))
Latitude: -23.43
Longitude: 26.52
Altitude: 544568.92 m
You can check to see if Fermi was in the SAA at that time:
[7]:
poshist.get_saa_passage(t0)
[7]:
array(False)
You might be interested to know where the Earth is (and its apparent radius) relative to Fermi:
[8]:
geocenter = poshist.get_geocenter_radec(t0)
print("Geocenter RA, Dec = {0:.2f}, {1:.2f}".format(*geocenter))
Geocenter RA, Dec = 172.53, 23.43
It might be useful to know if the sun is visible. Perhaps you’re interested in looking for solar emission or you’re worried about noise contributions from the sun:
[9]:
poshist.get_sun_visibility(t0)
[9]:
array(True)
For that matter, you could be interested in a particular known source, and it would be pretty helpful to know if it is even visible to Fermi at the time of interest:
[10]:
# the position of our source
ra = 324.3
dec = -20.8
poshist.location_visible(ra, dec, t0)
[10]:
array([ True])
Well, that’s good to know. But we want to look at the data for the closest detector to that position. We can figure that out. Where is detector ‘n0’ pointing?
[11]:
poshist.detector_pointing('n0', t0)
[11]:
(array(327.88023524), array(-18.18014898))
Ooh, we got lucky; that’s pretty close to our source position! What’s the detector-source angle?
[12]:
poshist.detector_angle(ra, dec, 'n0', t0)
[12]:
4.2721980564266975
Sometimes it’s useful to transform a source location of interest in equatorial coordinates to the Fermi inertial frame. You can do that by
[13]:
poshist.to_fermi_frame(ra, dec, t0)
[13]:
(array(39.67934005), array(24.14464044))
It’s important to note that the Fermi inertial frame is defined by azimuth (0-360 deg) and zenith (0-180 deg). Here, azimuth=0 is approximately the pointing of detector NaI 5, and increases counter-clockwise when looking down the LAT boresight. Zenith=0 is defined as the LAT boresight, and zenith=180 is directly below the spacecraft.
You can also go from Fermi (azimuth, zenith) coordinates to equatorial coordinates:
[14]:
# and where is the Fermi zenith (LAT boresight) in equatorial coordinates?
poshist.to_equatorial(0.0, 0.0, t0)
[14]:
(array(333.15399016), array(1.73430464))
You probably noticed that many of the outputs to these functions are returned as arrays. That is because instead of just defining a single time of interest, you can provide an array of times, and easily calculate any of these properties.
Now all of this great, but can we make a pretty plot? Yep. Use the SkyPlot (Equatorial Coordinates) or FermiSkyPlot (Fermi Inertial Coordinates) class in the gbm.plot module:
[15]:
%matplotlib inline
import matplotlib.pyplot as plt
from gbm.plot import SkyPlot, FermiSkyPlot
# initialize plot
skyplot = SkyPlot()
# plot the orientation of the detectors and Earth blockage at our time of interest
plt.show()
Woah! So there’s a lot going on here. First of all, there is a big blue blob in the middle of the plot; that’s the Earth as observed by Fermi. So nothing behind that is visible. The curved gray line going through the plot demarcates the Galactic Plane, and the dot is the Galactic Center. All of the gray labeled circles are the GBM detector pointings. Note these are not representative of the field-of-view (FoV) of the detectors (their FoV is virtually the whole sky). But they do allow you to visualize where the effective area of each detector is near its maximum. Finally, the yellow smiley-face is the sun.
The FermiSkyPlot class does the plot in Fermi inertial coordinates:
[16]:
fermiplot = FermiSkyPlot()
plt.show()
And to finish off our plotting fun, we can plot where Fermi is in orbit during our time of interest using the EarthPlot class:
[17]:
from gbm.plot import EarthPlot
# initialize plot
earthplot = EarthPlot()
# let's show the orbital path for +/-1000 s around our t0
Finally, you could be interested in some long period of time, or a period that crosses the day boundary, and therefore you need to use more than one POSHIST file. The PosHist class has a method specifically for this case. You can merge multiple PosHist objects into one object following:
merged_poshists = PosHist.merge([poshist1, poshist2, ...])
| 2023-03-23T15:10:43 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5125768184661865, "perplexity": 2311.8007171278914}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945168.36/warc/CC-MAIN-20230323132026-20230323162026-00470.warc.gz"}
|
https://gea.esac.esa.int/archive/documentation/GDR2/Gaia_archive/chap_cu9arch/sec_cu9arch_dr2/ssec_cu9arch_datalink.html
|
# 13.2.3 DataLink protocol for lightcurves / epoch photometry
Different Gaia data releases provide additional information for the catalogue sources. Apart from the five-parameter astrometric solution, other data sets like lightcurves, spectroscopic data, and variable-star classifications will be added in connection with the main Gaia catalogue. The richness and complexity of the Gaia data increases for each new release. Ensuring a reasonable data access performance as the volume grows poses a significant technical challenge.
The Gaia Archive deployed for Gaia DR2 offers the first implementation of a flexible IVOA protocol called DataLink. This protocol allows the discovery of extra metadata associated to a certain row (that is, an astronomical source) by the publication of a RESTful protocol that includes links to different kinds of data, including for instance time series, spectral data, or calibration files.
For Gaia DR2, the DataLink service provides access to photometric time series (lightcurves) of $\sim$$550\,000$ selected, variable objects. The Archive online help https://www.cosmos.esa.int/web/gaia-users/archive/help provides both a detailed description of the interfaces (see ’Datalink service’ section) and a hands-on tutorial on how to work with Gaia DR2 lightcurves (see ’Tutorials - Datalink and light curves’ section).
| 2022-10-04T19:20:29 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 2, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.23808377981185913, "perplexity": 5024.360722030277}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337524.47/warc/CC-MAIN-20221004184523-20221004214523-00354.warc.gz"}
|
https://www.usgs.gov/center-news/volcano-watch-dirty-research-flushing-mud-inside-k-lauea
|
# Volcano Watch — Dirty research: flushing mud from inside Kīlauea
Release Date:
A 1,262-m-deep (4,139-ft-deep) research hole was drilled in the southwest corner of Kīlauea's caldera in 1973. At the time, this was the deepest hole in the summit region of any active volcano on earth.
A 1,262-m-deep (4,139-ft-deep) research hole was drilled in the southwest corner of Kīlauea's caldera in 1973. At the time, this was the deepest hole in the summit region of any active volcano on earth. Funded by a National Science Foundation grant to the Colorado School of Mines, the hole was drilled to study the hydrothermal system and various geophysical properties above Kīlauea's magma reservoir. Standing water was encountered at a depth of about 488 m (1600 ft); below this water table, rocks were saturated all the way to the bottom of the hole, 160 m (525 ft) below sea level. Over the years, much valuable geophysical and geochemical information was acquired that has guided our interpretations of how Kīlauea operates.
But the hole is muddy. Drilling mud was not flushed from the hole after drilling. It has settled and gelled into a stiff, pudding-like mass that plugs the hole below a depth of about 473 m (1,554 ft). This causes a problem. Cracks and cavities in the rock surrounding the hole are clogged with mud, so that groundwater can't flow freely in and out of the hole. The hole needs to be cleaned to take advantage of new monitoring methods.
If groundwater can move easily into the hole, its level will rise if the rocks are squeezed and sink if the rocks relax. Think of what happens to a saturated sponge when you squeeze it, and you can get the picture. If we can measure the ups and downs of water in the hole, we have an inexpensive means of measuring earth strain in the caldera. With a clean hole, we can study the changes in rock permeability that control flow of groundwater toward sea level. If there were to be a significant increase in interaction between groundwater and hot rock or magma, we could monitor a possible build-up in steam pressure by a rapid rise in water level. Finally, we can trace changes in the chemical composition of the water before, during, and after eruptions.
A very precise device called a dilatometer may be put in the hole to monitor strain. It is so sensitive that it needs to be at least 200 m (650 ft) underground to take full advantage of its capability. Any shallower, the dilatometer "feels" spurious changes caused by heating and cooling near the earth's surface. If the sides of the hole can be cleaned sufficiently, the instrument can be bonded in place. If this works, a radio will send back to HVO information about the most subtle earth deformation that will help us anticipate the future at Kīlauea.
Perhaps it will be possible to have both a reliable water-level gage and a dilatometer in the hole, providing that a bypass can be made through the housing of the dilatometer to allow the water data to be transmitted by cable to the surface. And, we may also put a seismometer in the hole, so that it will be at a level with, or even below, the depth of some of the earthquakes within Kīlauea. A tiltmeter will be another instrument in the hole.
The cleaning of the hole is done with a drilling rig. Clean water is poured down the hole, and mud and dirty water are bailed to the surface and dumped into waiting trailers. In principle, it is like the old-fashioned windlass and bucket that were used to bail up water from hand-dug farmyard wells. We hope that enough of the drilling mud can be removed to clean the hole down to at least 300 m (1,000 ft) below the original water table and to establish free-flowing communication between the borehole and the surrounding aquifers. The work began last week and, at the time of writing, was having a big problem penetrating the stiff mud.
### Volcano Activity Update
The two sizable earthquakes during the past week did not affect the eruption. Eruptive activity at the Puu O`o vent continued unabated. Lava flows through a network of tubes from the vent to the seacoast where it enters the ocean in two locations near Kamokuna. The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying frequent collapses of the lava delta. The steam clouds are highly acidic and laced with glass particles.
Eight earthquakes were reported felt during the past week. Seven earthquakes originating from a very shallow depth beneath Volcano Village were felt only by residents of the surrounding area. The largest earthquake of the sequence occurred at 9:56 p.m. on Sunday, September 27. It had a magnitude of 4.6 and caused some damage in the neighborhood. Residents and businesses of Volcano reported the falling and breaking of items, the shattering of windows, and the cracking of masonry. The other felt earthquakes from the Volcano Village source occurred on September 26 at 5:27 p.m. (2.9 mag.), on September 27 at 10:10 p.m. (2.1 mag.), on September 28 at 1:59 a.m. (4.1 mag.), 2:17 a.m. (2.0 mag.), 2:23 a.m. (3.1 mag.) and 5:08 a.m. (3.3 mag.).
On Monday, September 28, at 8:39 p.m., a magnitude-4.8 earthquake was felt throughout the island. The earthquake was located 18 km (10.8 mi) southeast of Kīlauea summit at a depth of 9.5 km (5.7 mi). Residents of Puna and Hilo reported losses from items falling and breaking.
| 2020-08-04T02:57:04 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.39229804277420044, "perplexity": 1862.027360630573}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439735851.15/warc/CC-MAIN-20200804014340-20200804044340-00341.warc.gz"}
|
https://www.federalreserve.gov/econres/notes/feds-notes/accounting-for-covid-related-funding-credit-liquidity-and-loan-facilities-20210730.htm
|
July 30, 2021
### Accounting for COVID-19 Related Funding, Credit, Liquidity, and Loan Facilities in the Financial Accounts of the United States1
Matthew Hoops and Robert Kurtzman
In response to the COVID-19 pandemic, U.S. government policymakers took extraordinary actions to support the nation's households and businesses. As a part of this crisis response, the Federal Reserve established a number of funding, liquidity, and loan facilities to help maintain the flow of credit and improve financial conditions, in most cases with a backstop of funds appropriated by the U.S. Congress.
This note provides technical details on how these facilities have been accounted for in the Financial Accounts of the United States (Financial Accounts).2 The facilities generate financial flows across a number of sectors, and the Financial Accounts can be used to track these flows as part of analyses of the government response to the pandemic.
Overall, the Fed established 11 facilities in response to the COVID-19 pandemic.3 Five of the facilities are treated as on-balance-sheet facilities for the monetary authority, and the credit they provided can be seen directly on the monetary authority sector table in the Financial Accounts. The other six facilities were established as special purpose vehicles (SPVs), managed and funded by the Fed, with investments provided by the U.S. Department of the Treasury. Because of this unique structure, these SPVs are treated as off-balance-sheet facilities for the monetary authority and included in the other financial business sector, in accordance with System of National Accounts (SNA2008) guidelines.4
In section 1, we describe the accounting treatment for the on-balance-sheet facilities, and in section 2 we describe the treatment of facilities that were set up as off-balance-sheet SPVs. In section 3, we conclude.
#### Section 1: On-Balance-Sheet Facilities
Three of the facilities—the Primary Dealer Credit Facility (PDCF), the Money Market Mutual Fund Liquidity Facility (MMLF), and the Paycheck Protection Program Liquidity Facility (PPPLF)—show up directly as assets on the monetary authority balance sheet (table L.109), with corresponding liabilities on the balance sheets of U.S.-chartered depository institutions (table L.111), credit unions (table L.114), finance companies (table L.128), and security brokers and dealers (table L.130).5 Two others—the central bank liquidity swaps and the temporary Foreign and International Monetary Authorities (FIMA) Repo Facility—also appear as assets on the monetary authority balance sheet, with corresponding liabilities on the rest of the world balance sheet (table L.133).
Table 1 shows the amounts outstanding over the four quarters of 2020 and 2021:Q1 for all facilities on the monetary authority balance sheet. We provide further details on the treatment of these on-balance-sheet facilities below.
##### Table 1. On-Balance-Sheet Facilities and Their 2020 and 2021:Q1 Levels in the Accounts
Series Series Number Balances (millions of dollars)
2020:Q1 2020:Q2 2020:Q3 2020:Q4 2021:Q1
1. PDCF loans to broker-dealers FL713068663 36,178 2,489 233 485 25
2. Total MMLF loans FL713068803 50,084 21,375 7,088 3,621 200
3. MMLF loans to U.S.-chartered depository institutions FL763069143 27,546 11,756 3,898 1,992 110
4. MMLF loans to broker-dealers FL713068605 22,538 9,619 3,190 1,629 90
5. Total PPPLF loans FL713068873 0 68,215 67,573 50,428 60,135
6. PPPLF loans to depository institutions FL713068725 0 64,515 59,252 40,980 40,430
7. PPPLF loan to U.S.-chartered depository institutions FL713068775 0 64,014 58,750 40,584 40,203
8. PPPLF loans to credit unions FL713068743 0 501 502 396 227
9. PPPLF loans to finance companies FL713068863 0 3,700 8,321 9,448 19,705
10. Central bank liquidity swaps FL713091103 357,674 226,884 23,895 17,883 2,510
11. Temporary FIMA Repo Facility * 0 2 1,000 1,000 0
12. Treasury investment in the MMLF FL313094213 0 1,500 1,500 1,500 1,500
Note: * Denotes the series is not separately identified in the Financial Accounts. The table locations for each series are listed in the text. Series data sources are described in Appendix Table A1.
#### PDCF:
The PDCF loan balance (series FL713068663) is a component of line 21, "loans to brokers and dealers" (series FL713068665), which is part of the financial instrument category "depository institution loans n.e.c." on the monetary authority table (L.109).6 The corresponding liability is a component of line 18, "depository institution loans n.e.c." on the security brokers and dealers table (L.130).
#### MMLF:
The total MMLF loan balance (series FL713068803) is split between two financial instrument categories on the asset side of the monetary authority table.7
Just over half (55 percent) of the MMLF loan balance is classified as interbank loans and allocated to line 8 (series FL763069143) on the monetary authority table (L.109), which includes all U.S.-chartered depository institutions' (banks') commercial paper funded by borrowing from the Federal Reserve.8 The corresponding liability is a component of total bank borrowing from the Fed, shown on line 34 of the U.S.-chartered depository institutions table (L.111). In addition to the MMLF loan balance, line 34 also includes loan balances from the monetary authority through the AMLF, the PPPLF, and the discount window.
The remaining 45 percent of the MMLF loan balance is to broker dealers (series FL713068605), and as with the PDCF, is a component of line 21, "loans to brokers and dealers" (series FL713068665) on the monetary authority table (L.109). The corresponding liability is likewise a component of line 18, "depository institution loans n.e.c." on the liability side of the security brokers and dealers table (L.130).
As part of the creation of the MMLF, the Treasury provided credit protection to the Federal Reserve Bank of Boston through the Exchange Stabilization Fund (ESF).9 In 2020:Q2, the Treasury made a $1.5 billion investment in the MMLF, which is shown as line 44, "Treasury contributions to MMLF" (series FL313094213) under "miscellaneous liabilities" on the monetary authority table (L.109). #### PPPLF: Most of the PPPLF loans went to private depository institutions, shown on line 9 on the monetary authority table (L.109), while the remainder went to finance companies, shown on line 22.10 The total balance of the PPPLF can also be found as a separate series in the Financial Accounts (series FL713068873). The balance of PPPLF loans to U.S. private depository institutions includes both banks and credit unions and is reported on line 9, "PPPLF loans" (series FL713068725) on the monetary authority table (L.109). U.S.-chartered depository institutions account for the vast majority of PPPLF loans to depository institutions (series FL713068775), with the corresponding liability included as a component of line 34 (series FL713068715) on the U.S.-chartered depository institutions table (L.111).11 The residual balance of loans to U.S. private depository institutions were made to credit unions (series FL713068743), and the corresponding liability is included as part of line 17 (series FL474110005), "net interbank transactions" on the credit unions table (L.114). The remainder of the balance of loans extended under the PPPLF went to finance companies—which include mortgage finance companies and captive finance companies—and is shown on line 22 (series FL713068863) on the monetary authority table (L.109). The corresponding liability is considered "depository institution loans n.e.c." and is therefore included as a component of line 16 (series FL613168005) on the finance companies table (L.128). #### Central Bank Liquidity Swaps: The balance of central bank liquidity swaps is shown on line 26, "nonofficial foreign currencies" (series FL713091103) under "miscellaneous assets" on the monetary authority table (L.109).12 The corresponding liability is not separately identified but is included as a component of line 40, "nonofficial foreign currencies" (series FL263191103) on the rest of the world table (L.133). #### Temporary FIMA Repo Facility: The temporary FIMA Repo Facility balance is not separately identified on the monetary authority table (L.109); instead, it is included as a component of line 10, "security repurchase agreements" (series FL712051000).13 The corresponding liability is a component of line 26, "security repurchase agreements" (series FL262151003) on the rest of the world table (L.133). Because we do not have a separate series for the Temporary FIMA Repo in the Financial Accounts, we present the facility loan balance from the H.4.1 releases around quarter end in table 1; table A1 in appendix A has further details on the series. #### Section 2: Off-Balance-Sheet SPV Facilities In this section, we document the treatment in the Financial Accounts of the six off-balance-sheet facilities—the Municipal Liquidity Facility (Muni LF), the Main Street Lending Program (Main Street), the Commercial Paper Funding Facility (CPFF II), the Primary Corporate Credit Facility and Secondary Market Corporate Credit Facilities (jointly the CCFs), and the Term Asset-Backed Securities Loan Facility (TALF II)—that were established as SPVs, in which the Federal Reserve was the managing entity, while the Treasury maintained an investment made through the ESF.14 The SPV facilities are treated as off-balance-sheet facilities from the monetary authority, in that they are classified as separate financial entities included as part of the other financial business sector (table L.132), rather than the monetary authority sector. The SPV facilities in the other financial business sector borrow from the monetary authority and then lend directly to, or purchase assets from, other sectors of the economy. All of the SPV facilities are treated the same way on the monetary authority table and federal government table (L.106), though there are differences across facilities in how credit flows from the other financial business sector to other sectors of the economy. Accordingly, we begin our review with the shared treatment of the facilities.15 We then review how the loans from the other financial business sector flow to the other sectors of the economy for each of the facilities. #### Subsection 2.1: Shared Treatment in the Accounts: This subsection focuses on the shared treatment of the SPV facilities in the Financial Accounts. Table 2 shows the balances over the four quarters of 2020 and 2021:Q1 of all series described in our review. ##### Table 2. Off-Balance-Sheet SPVs and Their 2020 and 2021:Q1 Levels in the Accounts Series Series Number Balances (millions of dollars) 2020:Q1 2020:Q2 2020:Q3 2020:Q4 2021:Q1 Panel A: Treasury Equity Investments 1. Treasury investment in TALF II FL313094263 0 10,000 10,000 10,000 3,549 2. Treasury investment in the CPFF II FL313094223 0 10,000 10,000 10,000 10,000 3. Treasury investment in the Muni LF FL313094233 0 17,500 17,500 17,500 6,276 4. Treasury investment in the CCFs FL313094243 0 37,500 37,500 37,500 13,881 5. Treasury investment in Main Street FL313094253 0 37,500 37,500 37,500 16,572 6. Cash Deposits at monetary authority for TALF II, CPFF II, Muni LF, CCFs FL713129013 0 11,250 11,250 11,250 5,056 7. Cash Deposits at monetary authority for Main Street FL713129023 0 5,625 5,625 5,625 2,486 Panel B: Credit Flows from the Monetary Authority 8. MA loans to TALF II FL713068953 0 252 3,207 3,656 2,256 9. MA loans to the CPFF II FL713068913 0 4,243 30 0 0 10. MA loans to the Muni LF FL713068923 0 1,200 1,651 6,361 6,203 11. MA loans to the CCFs FL713068933 0 9,445 12,875 14,138 13,956 12. MA loans to Main Street FL713068943 0 0 2,195 16,502 16,488 Note: The table locations for each series are listed in the text. Series data sources are described in Appendix Table A2. Panel A of the table shows Treasury investments in each of the facilities made through the ESF. TALF II (series FL313094263) and the CPFF II (series FL313094223) each received$10 billion, while the Muni LF (series FL313094233) received $17.5 billion. The CCFs (series FL313094243) and Main Street (series FL313094253) each received$37.5 billion. These investments are treated as identified miscellaneous assets and are included as a component of line 15, "miscellaneous assets" on the federal government table (L.106). The corresponding liability is included as a component of line 26, investments in Federal Reserve facilities on the other financial businesses table (L.132).
The other financial business sector holds 15 percent of the Treasury's investment as cash deposits at the monetary authority, recorded as components of line 2, "checkable deposits and currency" on the other financial business table (L.132) and line 37 on the monetary authority table (L.109).16 The other 85 percent of the Treasury's investment is held as nonmarketable U.S. Treasury securities, which is shown on line 7 (series FL503061303) on the other financial business table (L.132) and as part of line 23 on the federal government table (L.106).17
Panel B of the table shows the balances of loans from the monetary authority to each of the SPV facilities—TALF II (series FL713068953), the CPFF II (series FL713068913), the Muni LF (FL713068923), the CCFs (series FL713068933), and Main Street (series FL713068943).18 These are classified as "depository institution loans n.e.c." to other financial business and are a component of line 23 (series FL713068505) on the monetary authority table (L.109).19 The corresponding loan liability is a component of line 20, "depository institution loans n.e.c." on the other financial businesses table (L.132).
#### Subsection 2.2: Loans from the Other Financial Business Sector to Other Sectors
The SPV facilities provided credit to a number of sectors across the economy. In the Financial Accounts, the facilities flow to the households and nonprofit organizations sector (table L.101), the nonfinancial corporate and noncorporate business sectors (tables L.103 and L.104, respectively), the exchange-traded funds (ETFs) sector (table L.124), and the state and local governments sector (table L.107).20 In this subsection, we provide detail on the flow of credit for each of the facilities as treated in the Financial Accounts.
The TALF II loan balance (series FL503069003) is a component of line 10, "loans (other loans and advances)" (series FL503069005) on the other financial business table (L.132). The corresponding liability is owed by domestic hedge funds and private equity funds, which are included by residual calculation in the household sector. These loans are included as a component of line 30 (series FL153169005), "other loans and advances," on the households and nonprofit organizations table (L.101).
The CPFF II balance is not separately identified but is included as part of line 6 (series FL503069105), "open market paper," on the other financial business table (L.132). The corresponding liability is not assigned to a particular sector but is part of total commercial paper shown on line 2 (series FL893169105) on the open market paper table (L.209).
The Muni LF balance is shown on line 9, "municipal securities" (series FL503062003) on the other financial business table (L.132). The corresponding liability is part of line 19 (series FL213162005) on the state and local governments table (L.107), which shows all municipal securities liabilities.
The CCFs purchased both U.S. corporate bonds and U.S. corporate bond ETFs; therefore, the CCF asset purchase balance is split between two lines on the other financial business table (L.132). The corporate bond purchase balance (series FL503063015) is a component of line 8, "corporate and foreign bonds" (series FL503063005).21 Some of the purchases were of investment-grade U.S. debt of companies in the domestic financial sector, while most were in the nonfinancial corporate business sector.22 The ETF purchase balance (series FL503064113) is included as a component of line 11, "corporate equities" (series FL503064105) on the other financial business table (L.132). The liability corresponding to the ETF purchases is a part of line 8, "total shares outstanding" (series LM564090005) on the ETFs table (L.124).
As with TALF II, the Main Street loan balance (the sum of series FL503069013 and FL503069023) is shown as a component of line 10 (series FL503069005), "loans (other loans and advances)," on the other financial business table (L.132).23 A fraction of the corresponding liability (series FL503069013) is included as a component of line 32 (series FL103169005), "other loans and advances" on the nonfinancial corporate business table (L.103). The remainder of the loans (series FL503069023) is included as part of line 20 (series FL113169005), "other loans and advances" on the nonfinancial noncorporate business table (L.104).24
#### Section 3: Conclusion
In this note, we have documented the financial accounting treatment in the Financial Accounts of the facilities that were established in response to the COVID-19 pandemic. While we focused on the levels series on the sector tables, the facilities can also be viewed in the context of the markets for the underlying financial instruments shown in the instrument tables of the Financial Accounts, or as part of the Integrated Macroeconomic Accounts. Readers can look to the interactive Financial Accounts Guide for additional detail on how the series discussed in this note are presented on other tables.25
#### Appendix A
In table A1, we present further detail on the data source for each on-balance-sheet series referenced in the main text. In table A2, we present such detail for each off-balance-sheet series referenced in the main text.
As explained in footnote 2, most data referred to in this note comes from the H.4.1. While H.4.1 data are released weekly (Wednesday), we use only quarter-end values in the Financial Accounts. Also note that a few series are derived from other sources, including the Bureau of Economic Analysis (BEA) International Transactions tables. For the BEA data, the level is calculated as the previous level plus the unadjusted transactions. For any data from other sources that are released monthly, we use only quarter-end values.
##### Table A1: Further Information on On-Balance-Sheet Referenced Series
Series Series Number Data Source Information
1. PDCF loans to broker-dealers FL713068663 Derived from the line "Primary Dealer Credit Facility" under "loans" on table 1 "Factors Affecting Reserve Balances of Depository Institutions" of the H.4.1.
2. Total MMLF loans FL713068803 Derived as 55 percent of the line "Money Market Mutual Fund Liquidity Facility" under "loans" on table 1 "Factors Affecting Reserve Balances of Depository Institutions" of the H.4.1.
3. MMLF loans to U.S.-chartered depository institutions FL763069143 See line 2 above.
4. MMLF loans to broker-dealers FL713068605 See line 2 above.
5. Total PPPLF loans FL713068873 Derived from the line "Paycheck Protection Program Liquidity Facility" under "loans" on table 1 "Factors Affecting Reserve Balances of Depository Institutions" of the H.4.1.
6. PPPLF loans to depository institutions FL713068725 Calculated residually as the difference between line 5 and line 9.
7. PPPLF loan to U.S.-chartered depository institutions FL713068775 Calculated residually as the difference between line 6 and line 8.
8. PPPLF loans to credit unions FL713068743 Derived from a Federal Reserve publication's detailed PPPLF spreadsheet, aggregated by entity type to isolate credit unions.
9. PPPLF loans to finance companies FL713068863 Derived from a Federal Reserve publication's detailed PPPLF spreadsheet, aggregated by entity type to isolate entities where 50 percent of balance sheet is loan assets.
10. Central bank liquidity swaps FL713091103 Derived from the line "central bank liquidity swaps" under "loans" on table 1 "Factors Affecting Reserve Balances of Depository Institutions" of the H.4.1
11. Temporary FIMA Repo Facility * Taken directly from the line "foreign official" under "repurchase agreements" on table 1 "Factors Affecting Reserve Balances of Depository Institutions" of the H.4.1. For 2020:Q1, see April 2, 2020, release. For 2020:Q2, see July 2, 2020, release. For 2020:Q3, see October 1, 2020, release. For 2020:Q4, see December 21, 2020, release. For 2021:Q1, see April 1, 2021, release.
12. Treasury investment in the MMLF FL313094213 Derived from the line "Money Market Mutual Fund Liquidity Facility (MMLF)" under "economic recovery program - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position. Accrued facility fees are excluded.
Additional Items Referenced in the text
13. Central bank liquidity swaps (liability of the rest of the world sector) FL263191103 Derived from the line "short term" (line 34, under "assets by sector of U.S. holder" → "net U.S. acquisition of other investment assets" → "central bank" → "currency and deposits" → "deposits") on BEA International Transactions table 8.1 "U.S. International Financial Transactions for Other Investment."
14. Federal Reserve securities repurchases including temporary FIMA Repo Facility (asset of the monetary authority sector) FL712051000 Derived from the line "repurchase agreements" under "securities, unamortized premiums and discounts, repurchase agreements, and loans" on table 5 "Consolidated Statement of Condition of All Federal Reserve Banks" of the H.4.1. Note that this series in the Financial Accounts includes all repo, and not just that through the temporary FIMA Repo Facility.
15. Federal Reserve securities repurchases including temporary FIMA Repo Facility (liability of the rest of the world sector) FL262151003 Derived from the line "of which: resale agreements" (line 39, under "assets by sector of U.S. holder" → "net U.S. acquisition of other investment assets" → "deposit-taking institutions except central bank" → "currency and deposits" → "deposits") plus the line "of which: resale agreements" (line 51, under "assets by sector of U.S. holder" → "net U.S. acquisition of other investment assets" → "other financial institutions and nonfinancial institutions except general government" → "loans") on BEA International Transactions table 8.1 "U.S. International Financial Transactions for Other Investment."
Note: * Denotes the series is not separately identified in the Financial Accounts. The table locations for each series are listed in the text.
##### Table A2. Further Information on Off-Balance-Sheet Referenced Series
Series Series Number Data Source Information
Panel A: Treasury Equity Investments
1. Treasury investment in TALF II FL313094263 Derived from the line "Term Asset-Backed Securities Loan Facility (TALF)" under "economic recovery program - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position.
2. Treasury investment in the CPFF II FL313094223 Derived from the line "Commercial Paper Funding Facility (CPFF)" under "economic recovery program - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position.
3. Treasury investment in the Muni LF FL313094233 Derived from the line "Municipal Liquidity Facility (MLF)" under "economic recovery programs - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position.
4. Treasury investment in the CCFs FL313094243 Derived from the line "Corporate Credit Facilities (CCF)" under "economic recovery programs - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position.
5. Treasury investment in Main Street FL313094253 Derived from the line "Main Street Loan Program (MSLP)" under "economic recovery program - investments and other" on the U.S. Department of the Treasury Exchange Stabilization Fund Statement of Financial Position.
6. Cash deposits at monetary authority for TALF II, CPFF II, Muni LF, CCFs FL713129013 Derived from the H.4.1 Federal Reserve statistical release, notes for line "Treasury contributions to credit facilities" on table 5 "Consolidated Statement of Condition of All Federal Reserve Banks," computed as 15 percent of equity investment due to Commercial Paper Funding Facility II LLC, Corporate Credit Facilities LLC, Municipal Liquidity Facility LLC, and TALF II LLC.
7. Cash deposits at monetary authority for Main Street FL713129023 Derived from the H.4.1 Federal Reserve statistical release, notes for line "Treasury contributions to credit facilities" on table 5 "Consolidated Statement of Condition of All Federal Reserve Banks," computed as 15 percent of equity investment due to MS Facilities LLCs.
Panel B: Credit Flows from the Monetary Authority
8. MA loans to TALF II FL713068953 Derived from the line "TALF II LLC" on table 4 "Information on Principal Accounts of Credit Facilities LLCs" of the H.4.1.
9. MA loans to the CPFF II FL713068913 Derived from the line "Commercial Paper Funding Facility II LLC" on table 4 "Information on Principal Accounts of Credit Facilities LLCs" of the H.4.1.
10. MA loans to the Muni LF FL713068923 Derived from the line "Municipal Liquidity Facility LLC" on table 4 "Information on Principal Accounts of Credit Facilities LLCs" of the H.4.1.
11. MA loans to the CCFs FL713068933 Derived from the line "Corporate Credit Facilities LLC" on table 4 "Information on Principal Accounts of Credit Facilities LLCs" of the H.4.1.
12. MA loans to Main Street FL713068943 Derived from the line "MS Facilities LLC (Main Street Lending Program)" on table 4 "Information on Principal Accounts of Credit Facilities LLCs" of the H.4.1.
Note: The table locations for each series are listed in the text.
1. We are grateful for the comments and suggestions of Marco Cagetti, Joshua Louria, Maria Perozek, and Paul Smith. The views presented in this note are those of the authors and do not necessarily reflect those of the Federal Reserve Board or the Federal Reserve System. Return to text
2. Though we are interested in describing the treatment of the Fed facilities in the Financial Accounts, importantly, a significant number of series discussed as part of this note are derived from the Federal Reserve's H.4.1 Statistical Release "Factors Affecting Reserve Balances of Depository Institutions and Condition Statement of Federal Reserve Banks." Note that our treatment of some of the facilities as off-balance-sheet facilities can differ from the H.4.1. In appendix A, we provide further details on the underlying data sources for each series. Return to text
3. The list of facilities that we review corresponds to those listed (as of June 29, 2021) at https://www.federalreserve.gov/funding-credit-liquidity-and-loan-facilities.htm. Note that the Fed also created facilities in response to the 2007–08 financial crisis, though this note focuses only on the treatment of the recently created loan facilities. Return to text
4. The treatment is different in the H.4.1 (as explained in the "note on consolidation" following table 6 of the H.4.1). Specifically, the assets and liabilities of the SPVs are consolidated with the assets and liabilities of the Federal Reserve Banks on the H.4.1. The SNA2008 guidelines can be found at https://unstats.un.org/unsd/nationalaccount/sna2008.asp. Return to text
5. The series descriptions, table numbers, and line numbers come from the Financial Accounts of the United States June 10, 2021, release (see https://www.federalreserve.gov/releases/z1/20210610/z1.pdf). Some series do not show up directly on the tables, but can be found using the advanced search tool (see https://www.federalreserve.gov/apps/fof/AdvancedSearch.aspx?ck=a). Here and throughout our analysis, we focus on the levels tables ("L" tables) and associated levels series (that is, those with "FL" or "LM" prefixes) for financial and nonfinancial sectors in the Financial Accounts. It is important to note that these facilities also affect other tables, such as the transactions and instruments tables. Return to text
7. The split is based on information provided by the Federal Reserve Bank of Boston. For details on the MMLF, see https://www.federalreserve.gov/monetarypolicy/mmlf.htm. Return to text
8. Series FL763069143 includes 66 percent of the Asset-Backed Commercial Paper Money Market Mutual Fund Liquidity Facility (AMLF) for the period 2008:Q3 through 2009:Q3. Return to text
9. Though the Treasury provided credit protection to the MMLF, the facility is not classified as "off-balance-sheet" in the Financial Accounts because it is not a SPV. Return to text
11. This treatment is similar to the MMLF. See the MMLF subsection for further details. Return to text
12. For details on the central bank liquidity swaps, see https://www.federalreserve.gov/monetarypolicy/central-bank-liquidity-swaps.htm. Return to text
13. For details on the temporary FIMA Repo Facility, see https://www.federalreserve.gov/monetarypolicy/fima-repo-facility.htm. For details on how the temporary FIMA Repo Facility is treated on the H.4.1, see the April 9, 2020, release, which is available at https://www.federalreserve.gov/releases/h41/20200409. Return to text
14. In the Financial Accounts, Treasury investments made through the ESF in Federal Reserve facilities are treated as identified miscellaneous assets (table L.232). For details on the ESF, see https://home.treasury.gov/policy-issues/international/exchange-stabilization-fund. Return to text
15. In the Financial Accounts, we treat the CCFs as a single facility, so we do not separate out the PMCCF from the SMCCF in our analysis. Return to text
16. Line 37 on the monetary authority table (L.109) consists of deposits due to designated financial market utilities and SPV facilities. SPV cash deposits at the monetary authority are shown in panel A of table 2 for the sum of TALF II, the CPFF II, the Muni LF, and the CCFs (series FL713129013), and separately for Main Street (series FL713129023). The size of the cash deposit is computed as 15 percent of the initial Treasury investment for the corresponding facilities. Return to text
17. Note that for series FL503061303, the initial investment in nonmarketable U.S. Treasury securities was 85 percent, but the series now includes reinvested interest as reported in the U.S. Treasury Monthly Statement of the Public Debt of the United States. See, for example, the line "SPV demand" under "domestic series" under "nonmarketable" on page 10 of the September 30, 2020, statement, which is available at https://www.treasurydirect.gov/govt/reports/pd/mspd/2020/opdm092020.pdf PDF.
Also note that nonmarketable U.S. Treasury securities are shown on line 23 on the federal government table (L.106). The nonmarketable U.S. Treasury securities holdings of other financial business are only a small percentage of total nonmarketable U.S. Treasury securities outstanding. Return to text
18. For details on TALF II, see https://www.federalreserve.gov/monetarypolicy/talf.htm. For details on the CPFF II, see https://www.federalreserve.gov/monetarypolicy/cpff.htm. For details on the Muni LF, see https://www.federalreserve.gov/monetarypolicy/muni.htm. For details on the PMCCF and SMCCF, see https://www.federalreserve.gov/monetarypolicy/pmccf.htm and https://www.federalreserve.gov/monetarypolicy/smccf.htm, respectively. For details on Main Street, see https://www.federalreserve.gov/monetarypolicy/mainstreetlending.htm. Return to text
19. The sum of the loans made through the vehicles is also in the Financial Accounts; see series FL713068905. Return to text
20. SPV holdings in the other financial business sector of ETFs, corporate bonds, and municipal bonds are the outstanding facility asset purchases and can differ from the outstanding principal amount of the loan to the SPV (see the notes on H.4.1 table 4). That said, more often than not they are the same, and they are always close in size. Therefore, though we include the series codes for SPV holdings in the other financial business sector in this subsection text, we do not include a separate table for the values in this section. Return to text
21. Corporate bond purchases are residually calculated by subtracting the ETF level from the level of SPV holdings for the CCFs. The SPV holdings for the CCFs is from the H.4.1 table 4 "Information on Principal Accounts of Credit Facilities LLCs:" the "outstanding amount of facility asset purchases" column and the "corporate credit facilities LLC" row. The ETF level is from the aggregated Federal Reserve Secondary Market Corporate Credit Facility spreadsheet: the "position summary-ETF" tab and the "market value" column. Return to text
22. To be more specific, the corresponding liability is split between the following: line 1, "total liabilities" on the corporate and foreign bonds table (L.213); line 2, "foreign deposits" (series FL103091003) on the nonfinancial corporate business table (L.103); and line 38, "corporate and foreign bonds" (FL793163005) on the domestic financial sectors table (L.108). Return to text
23. In this case, Main Street loans are considered a part of "syndicated loans to nonfinancial corporate business" (series FL503069805). Note that for Main Street and TALF II, separate detail is not shown on the sector tables; however, this detail is shown on lines 53 through 56 on the other loans and advances table (L.216). Also note that the sum of Main Street and TALF II loans can be found as series FL503069075. Return to text
24. The breakdown of this split is determined by the Federal Reserve Bank of Boston. Return to text
25. The Financial Accounts Guide can be found at https://www.federalreserve.gov/apps/fof. Return to text
| 2022-05-18T14:32:33 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.18864354491233826, "perplexity": 9730.1844796904}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662522270.37/warc/CC-MAIN-20220518115411-20220518145411-00604.warc.gz"}
|
https://par.nsf.gov/biblio/10098858-observations-mechanochemical-insertion-zinc-ii-copper-ii-magnesium-ii-select-other-metal-ii-ions-porphyrins
|
Observations on the Mechanochemical Insertion of Zinc(II), Copper(II), Magnesium(II), and Select Other Metal(II) Ions into Porphyrins
Authors:
;
Award ID(s):
Publication Date:
NSF-PAR ID:
10098858
Journal Name:
Inorganic Chemistry
ISSN:
0020-1669
We present 10 main-sequence ALPINE galaxies (log (M/M⊙) = 9.2−11.1 and ${\rm SFR}=23-190\, {\rm M_{\odot }\, yr^{-1}}$) at z ∼ 4.5 with optical [O ii] measurements from Keck/MOSFIRE spectroscopy and Subaru/MOIRCS narrow-band imaging. This is the largest such multiwavelength sample at these redshifts, combining various measurements in the ultraviolet, optical, and far-infrared including [C ii]158 $\mu$m line emission and dust continuum from ALMA and H α emission from Spitzer photometry. For the first time, this unique sample allows us to analyse the relation between [O ii] and total star-formation rate (SFR) and the interstellar medium (ISM) properties via [O ii]/[C ii] and [O ii]/H α luminosity ratios at z ∼ 4.5. The [O ii]−SFR relation at z ∼ 4.5 cannot be described using standard local descriptions, but is consistent with a metal-dependent relation assuming metallicities around $50{{\ \rm per\ cent}}$ solar. To explain the measured dust-corrected luminosity ratios of $\log (L_{\rm [OII]}/L_{\rm [CII]}) \sim 0.98^{+0.21}_{-0.22}$ and $\log (L_{\rm [OII]}/L_{\rm H\alpha }) \sim -0.22^{+0.13}_{-0.15}$ for our sample, ionization parameters log (U) < −2 and electron densities $\log (\rm n_e / {\rm [cm^{-3}]}) \sim 2.5-3$ are required. The former is consistent with galaxies at z ∼ 2−3, however lower than at z > 6. The latter may be slightly higher than expected given the galaxies’ specific SFR. Themore »
| 2022-11-29T05:32:55 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7505631446838379, "perplexity": 4057.9612650857275}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710685.0/warc/CC-MAIN-20221129031912-20221129061912-00797.warc.gz"}
|
http://home.fnal.gov/~mrenna/lutp0613man2/node181.html
|
Next: Beam Remnants (and Multiple Up: Multiple Interactions Previous: The simple model Contents
### A model with varying impact parameters
Up to this point, it has been assumed that the initial state is the same for all hadron collisions, whereas in fact each collision also is characterized by a varying impact parameter . Within the classical framework of the model reviewed here, is to be thought of as a distance of closest approach, not as the Fourier transform of the momentum transfer. A small value corresponds to a large overlap between the two colliding hadrons, and hence an enhanced probability for multiple interactions. A large , on the other hand, corresponds to a grazing collision, with a large probability that no parton-parton interactions at all take place.
In order to quantify the concept of hadronic matter overlap, one may assume a spherically symmetric distribution of matter inside the hadron, . For simplicity, the same spatial distribution is taken to apply for all parton species and momenta. Several different matter distributions have been tried, and are available. We will here concentrate on the most extreme one, a double Gaussian
(210)
This corresponds to a distribution with a small core region, of radius and containing a fraction of the total hadronic matter, embedded in a larger hadron of radius . While it is mathematically convenient to have the origin of the two Gaussians coinciding, the physics could well correspond to having three disjoint core regions, reflecting the presence of three valence quarks, together carrying the fraction of the proton momentum. One could alternatively imagine a hard hadronic core surrounded by a pion cloud. Such details would affect e.g. the predictions for the distribution in elastic scattering, but are not of any consequence for the current topics. To be specific, the values and were picked as default values. It should be noted that the overall distance scale never enters in the subsequent calculations, since the inelastic, non-diffractive cross section is taken from literature rather than calculated from the .
Compared to other shapes, like a simple Gaussian, the double Gaussian tends to give larger fluctuations, e.g. in the multiplicity distribution of minimum-bias events: a collision in which the two cores overlap tends to have a strongly increased activity, while ones where they do not are rather less active. One also has a biasing effect: hard processes are more likely when the cores overlap, thus hard scatterings are associated with an enhanced multiple interaction rate. This provides one possible explanation for the experimental pedestal effect' [UA187]. Recent studies of CDF data [Fie02,Mor02] have confirmed that indeed something more peaked than a single Gaussian is required to understand the transition from minimum-bias to underlying-event activity.
For a collision with impact parameter , the time-integrated overlap between the matter distributions of the colliding hadrons is given by
(211)
The necessity to use boosted distributions has been circumvented by a suitable scale transformation of the and coordinates.
The overlap is obviously strongly related to the eikonal of optical models. We have kept a separate notation, since the physics context of the two is slightly different: is based on the quantum mechanical scattering of waves in a potential, and is normally used to describe the elastic scattering of a hadron-as-a-whole, while comes from a purely classical picture of point-like partons distributed inside the two colliding hadrons. Furthermore, the normalization and energy dependence is differently realized in the two formalisms.
The larger the overlap is, the more likely it is to have interactions between partons in the two colliding hadrons. In fact, there should be a linear relationship
(212)
where counts the number of interactions when two hadrons pass each other with an impact parameter . The constant of proportionality, , is related to the parton-parton cross section and hence increases with c.m. energy.
For each given impact parameter, the number of interactions is assumed to be distributed according to a Poisson. If the matter distribution has a tail to infinity (as the double Gaussian does), events may be obtained with arbitrarily large values. In order to obtain finite total cross sections, it is necessary to assume that each event contains at least one semi-hard interaction. The probability that two hadrons, passing each other with an impact parameter , will actually undergo a collision is then given by
(213)
according to Poisson statistics. The average number of interactions per event at impact parameter is now
(214)
where the denominator comes from the removal of hadron pairs which pass without colliding, i.e. with .
The relationship was earlier introduced for the average number of interactions per non-diffractive, inelastic event. When averaged over all impact parameters, this relation must still hold true: the introduction of variable impact parameters may give more interactions in some events and less in others, but it does not affect either or . For the former this is because the perturbative QCD calculations only depend on the total parton flux, for the latter by construction. Integrating eq. () over , one then obtains
(215)
For , and given, with , can thus always be found (numerically) by solving the last equality.
The absolute normalization of is not interesting in itself, but only the relative variation with impact parameter. It is therefore useful to introduce an enhancement factor' , which gauges how the interaction probability for a passage with impact parameter compares with the average, i.e.
(216)
The definition of the average is a bit delicate, since the average number of interactions per event is pushed up by the requirement that each event contain at least one interaction. However, an exact meaning can be given [Sjö87a].
With the knowledge of , the function of the simple model generalizes to
(217)
The naïve generation procedure is thus to pick a according to the phase space , find the relevant and plug in the resulting in the formalism of the simple model. If at least one hard interaction is generated, the event is retained, else a new is to be found. This algorithm would work fine for hadronic matter distributions which vanish outside some radius, so that the phase space which needs to be probed is finite. Since this is not true for the distributions under study, it is necessary to do better.
By analogy with eq. (), it is possible to ask what the probability is to find the hardest scattering of an event at . For each impact parameter separately, the probability to have an interaction at is given by , and this should be multiplied by the probability that the event contains no interactions at a scale , to yield the total probability distribution
(218)
If the treatment of the exponential is deferred for a moment, the distribution in and appears in factorized form, so that the two can be chosen independently of each other. In particular, a high- QCD scattering or any other hard scattering can be selected with whatever kinematics desired for that process, and thereafter assigned some suitable hardness' . With the chosen according to , the neglected exponential can now be evaluated, and the event retained with a probability proportional to it. From the scale of the selected interaction, a sequence of softer values may again be generated as in the simple model, using the known . This sequence may be empty, i.e. the event need not contain any further interactions.
It is interesting to understand how the algorithm above works. By selecting according to , i.e. , the primary distribution is maximally biased towards small impact parameters. If the first interaction is hard, by choice or by chance, the integral of the cross section above is small, and the exponential close to unity. The rejection procedure is therefore very efficient for all standard hard processes in the program -- one may even safely drop the weighting with the exponential completely. The large value is also likely to lead to the generation of many further, softer interactions. If, on the other hand, the first interaction is not hard, the exponential is no longer close to unity, and many events are rejected. This pulls down the efficiency for minimum bias' event generation. Since the exponent is proportional to , a large leads to an enhanced probability for rejection, whereas the chance of acceptance is larger with a small . Among events where the hardest interaction is soft, the distribution is therefore biased towards larger values (smaller ), and there is a small probability for yet softer interactions.
To evaluate the exponential factor, the program pretabulates the integral of at the initialization stage, and further increases the Monte Carlo statistics of this tabulation as the run proceeds. The grid is concentrated towards small , where the integral is large. For a selected value, the integral is obtained by interpolation. After multiplication by the known factor, the exponential factor may be found.
In this section, nothing has yet been assumed about the form of the spectrum. Like in the impact-parameter-independent case, it is possible to use a sharp cut-off at some given value. However, now each event is required to have at least one interaction, whereas before events without interactions were retained and put at . It is therefore aesthetically more appealing to assume a gradual turn-off, so that a (semi)hard interaction can be rather soft part of the time. The matrix elements roughly diverge like for . They could therefore be regularized as follows. Firstly, to remove the behaviour, multiply by a factor . Secondly, replace the argument in by . If one has included a factor by a rescaling of the argument, as mentioned earlier, replace by .
With these substitutions, a continuous spectrum is obtained, stretching from to . For the standard perturbative QCD cross section is recovered, while values are strongly damped. The scale, which now is the main free parameter of the model, in practice comes out to be of the same order of magnitude as the sharp cut-off did, i.e. 1.5-2 GeV at collider energies, but typically about 10% higher.
Above we have argued that and should only have a slow energy dependence, and even allowed for the possibility of fixed values. For the impact-parameter-independent picture this works out fine, with all events being reduced to low- two-string ones when the c.m. energy is reduced. In the variable-impact-parameter picture, the whole formalism only makes sense if , see e.g. eq. (). Since does not vanish with decreasing energy, but would do that for a fixed , this means that has to be reduced significantly at low energies, possibly even more than implied by our assumed energy dependence. The more `sophisticated' model of this section therefore makes sense at collider energies, whereas it may not be well suited for applications at fixed-target energies. There one should presumably attach to a picture of multiple soft Pomeron exchanges.
Next: Beam Remnants (and Multiple Up: Multiple Interactions Previous: The simple model Contents
Stephen Mrenna 2007-10-30
| 2018-01-17T20:11:50 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8674652576446533, "perplexity": 582.1459401762511}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084886964.22/warc/CC-MAIN-20180117193009-20180117213009-00525.warc.gz"}
|
http://dlmf.nist.gov/33.12
|
# §33.12 Asymptotic Expansions for Large
## §33.12(i) Transition Region
When and , the outer turning point is given by ; compare (33.2.2). Define
33.12.1
Then as ,
For derivations and additional terms in the expansions in this subsection see Abramowitz and Rabinowitz (1954) and Fröberg (1955).
## §33.12(ii) Uniform Expansions
With the substitution , Equation (33.2.1) becomes
Then, by application of the results given in §§2.8(iii) and 2.8(iv), two sets of asymptotic expansions can be constructed for and when .
The first set is in terms of Airy functions and the expansions are uniform for fixed and , where is an arbitrary small positive constant. They would include the results of §33.12(i) as a special case.
The second set is in terms of Bessel functions of orders and , and they are uniform for fixed and , where again denotes an arbitrary small positive constant.
Compare also §33.20(iv).
| 2013-05-25T08:46:17 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9652440547943115, "perplexity": 1260.770143188682}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368705790741/warc/CC-MAIN-20130516120310-00072-ip-10-60-113-184.ec2.internal.warc.gz"}
|
http://trove.nla.gov.au/work/195944?q&versionId=208336
|
# 2003, English, Article edition: Geometric crystal and tropical R for Formula Kuniba, A.; Okado, M.; Takagi, T.; ...
#### User activity
##### Share to:
Bookmark: http://trove.nla.gov.au/version/208336
Physical Description
• text/html
Published
• Oxford University Press
• 2003-01-01 00:00:00.0
Language
• English
### Edition details
Title
• Geometric crystal and tropical R for Formula
Author
• Kuniba, A.
• Takagi, T.
Published
• Oxford University Press
• 2003-01-01 00:00:00.0
Physical Description
• text/html
Subjects
Notes
• We construct a geometric crystal for the affine Lie algebra $${D}_{n}^{\left(1\right)}$$ in the sense of Berenstein and Kazhdan. Based on a matrix realization including a spectral parameter, we prove uniqueness and explicit form of the tropical R , the birational map that intertwines products of the geometric crystals. The tropical R commutes with geometric Kashiwara operators and satisfies the Yang-Baxter equation. It is subtraction-free and yields a piecewise linear formula of the combinatorial R for crystals upon ultradiscretization.
• Copyright (C) 2003, Oxford University Press
Language
• English
Contributed by
OAIster
## With access conditions
• Set up My libraries
### How do I set up "My libraries"?
In order to set up a list of libraries that you have access to, you must first login or sign up. Then set up a personal list of libraries from your profile page by clicking on your user name at the top right of any screen.
• All (1)
• Unknown (1)
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
## User activity
#### Tags
What are tags? Add a tag
e.g. test cricket, Perth (WA), "Parkes, Henry"
Separate different tags with a comma. To include a comma in your tag, surround the tag with double quotes.
Be the first to add a tag for this edition
| 2017-05-24T07:01:39 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6005254983901978, "perplexity": 7706.000524085294}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463607802.75/warc/CC-MAIN-20170524055048-20170524075048-00221.warc.gz"}
|
https://www.anl.gov/topic/washington
|
# Washington
## Filter Results
• ### Seventeen from Argonne recognized with Secretary of Energy’s Honor Awards
Recognitions included achievements in supercomputing and characterizing COVID-19
• ### High-impact research: How meteorite strikes may change quartz on the Earth’s surface
Scientists using a unique combination of capabilities at the Advanced Photon Source have learned more about how meteorites affect one of the most abundant materials in the Earth’s crust.
• ### Department of Energy awards $3.15 million to Argonne to support collaborations with industry Awards come from DOE’s Technology Commercialization Fund. • ### Washington Argonne’s collaborations in Washington and across the United States have led to groundbreaking discoveries and development of new technologies that help meet the nation’s needs for sustainable energy, economic prosperity, and security. • ### Argonne researchers focus on grid cybersecurity to pave the way for a clean energy future Enhancing grid cybersecurity to prepare for a clean energy future • ### New version of Earth model captures detailed climate dynamics DOE labs collaborate on new high-resolution Earth systems model to predict climate trends into the next century. • ### Argonne lends a hand toward climate and weather understanding DOE user facility provides detailed weather and climate pattern data for more accurate prediction models. • ### Magic Tricks, Virtual Reality, and Trash Sorting: DOE STEM-CON Exposes Chicago’s South Side to Diverse STEM Opportunities and AI Advances DOE’s Argonne National Laboratory collaborated with South Side of Chicago’s Gary Comer Youth Center to host a multi-national DOE lab exhibition for local youth. • ### Department of Energy awards$4.6 million to Argonne to support collaborations with industry
Argonne National Laboratory received \$4.6 million to fund 12 projects across four research divisions.
• ### Ultrathin and ultrafast: scientists pioneer new technique for two-dimensional material analysis
Discovery allows scientists to look at how 2D materials move with ultrafast precision.
| 2023-02-05T17:53:23 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24137774109840393, "perplexity": 14550.195691972021}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500273.30/warc/CC-MAIN-20230205161658-20230205191658-00663.warc.gz"}
|
http://dlmf.nist.gov/27.4
|
# §27.4 Euler Products and Dirichlet Series
The fundamental theorem of arithmetic is linked to analysis through the concept of the Euler product. Every multiplicative $f$ satisfies the identity
27.4.1 $\sum_{n=1}^{\infty}f(n)=\prod_{p}\left(1+\sum_{r=1}^{\infty}f(p^{r})\right),$
if the series on the left is absolutely convergent. In this case the infinite product on the right (extended over all primes $p$) is also absolutely convergent and is called the Euler product of the series. If $f(n)$ is completely multiplicative, then each factor in the product is a geometric series and the Euler product becomes
27.4.2 $\sum_{n=1}^{\infty}f(n)=\prod_{p}(1-f(p))^{-1}.$
Euler products are used to find series that generate many functions of multiplicative number theory. The completely multiplicative function $f(n)=n^{-s}$ gives the Euler product representation of the Riemann zeta function $\mathop{\zeta\/}\nolimits\!\left(s\right)$25.2(i)):
27.4.3 $\mathop{\zeta\/}\nolimits\!\left(s\right)=\sum_{n=1}^{\infty}n^{-s}=\prod_{p}(% 1-p^{-s})^{-1},$ $\realpart{s}>1$.
The Riemann zeta function is the prototype of series of the form
27.4.4 $F(s)=\sum_{n=1}^{\infty}f(n)n^{-s},$
called Dirichlet series with coefficients $f(n)$. The function $F(s)$ is a generating function, or more precisely, a Dirichlet generating function, for the coefficients. The following examples have generating functions related to the zeta function:
27.4.5 $\displaystyle\sum_{n=1}^{\infty}\mathop{\mu\/}\nolimits\!\left(n\right)n^{-s}$ $\displaystyle=\frac{1}{\mathop{\zeta\/}\nolimits\!\left(s\right)},$ $\realpart{s}>1$, 27.4.6 $\displaystyle\sum_{n=1}^{\infty}\mathop{\phi\/}\nolimits\!\left(n\right)n^{-s}$ $\displaystyle=\frac{\mathop{\zeta\/}\nolimits\!\left(s-1\right)}{\mathop{\zeta% \/}\nolimits\!\left(s\right)},$ $\realpart{s}>2$, 27.4.7 $\displaystyle\sum_{n=1}^{\infty}\mathop{\lambda\/}\nolimits\!\left(n\right)n^{% -s}$ $\displaystyle=\frac{\mathop{\zeta\/}\nolimits\!\left(2s\right)}{\mathop{\zeta% \/}\nolimits\!\left(s\right)},$ $\realpart{s}>1$, 27.4.8 $\displaystyle\sum_{n=1}^{\infty}|\mathop{\mu\/}\nolimits\!\left(n\right)|n^{-s}$ $\displaystyle=\frac{\mathop{\zeta\/}\nolimits\!\left(s\right)}{\mathop{\zeta\/% }\nolimits\!\left(2s\right)},$ $\realpart{s}>1$, 27.4.9 $\displaystyle\sum_{n=1}^{\infty}2^{\mathop{\nu\/}\nolimits\!\left(n\right)}n^{% -s}$ $\displaystyle=\frac{(\mathop{\zeta\/}\nolimits\!\left(s\right))^{2}}{\mathop{% \zeta\/}\nolimits\!\left(2s\right)},$ $\realpart{s}>1$, 27.4.10 $\displaystyle\sum_{n=1}^{\infty}\mathop{d_{k}\/}\nolimits\!\left(n\right)n^{-s}$ $\displaystyle=(\mathop{\zeta\/}\nolimits\!\left(s\right))^{k},$ $\realpart{s}>1$,
27.4.11 $\sum_{n=1}^{\infty}\mathop{\sigma_{\alpha}\/}\nolimits\!\left(n\right)n^{-s}=% \mathop{\zeta\/}\nolimits\!\left(s\right)\mathop{\zeta\/}\nolimits\!\left(s-% \alpha\right),$ $\realpart{s}>\max(1,1+\realpart{\alpha})$,
27.4.12 $\displaystyle\sum_{n=1}^{\infty}\mathop{\Lambda\/}\nolimits\!\left(n\right)n^{% -s}$ $\displaystyle=-\frac{\mathop{\zeta\/}\nolimits'\!\left(s\right)}{\mathop{\zeta% \/}\nolimits\!\left(s\right)},$ $\realpart{s}>1$, 27.4.13 $\displaystyle\sum_{n=2}^{\infty}(\mathop{\ln\/}\nolimits n)n^{-s}$ $\displaystyle=-\mathop{\zeta\/}\nolimits'\!\left(s\right),$ $\realpart{s}>1$. Symbols: $\mathop{\zeta\/}\nolimits\!\left(s\right)$: Riemann zeta function, $\mathop{\ln\/}\nolimits z$: principal branch of logarithm function, $\realpart{}$: real part and $n$: positive integer Referenced by: §27.4 Permalink: http://dlmf.nist.gov/27.4.E13 Encodings: TeX, pMML, png Change of Notation (effective with 1.0.10): The notation for logarithm has been changed to $\mathop{\ln\/}\nolimits$ from $\mathrm{log}$. Reported 2015-06-08
In (27.4.12) and (27.4.13) $\mathop{\zeta\/}\nolimits'\!\left(s\right)$ is the derivative of $\mathop{\zeta\/}\nolimits\!\left(s\right)$.
| 2015-10-06T09:46:58 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 95, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9929710030555725, "perplexity": 495.67564711702835}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443736678574.43/warc/CC-MAIN-20151001215758-00220-ip-10-137-6-227.ec2.internal.warc.gz"}
|
https://pdglive.lbl.gov/DataBlock.action?node=M300K01
|
#### $\mathbf {{{\mathit X}{(2000)}} }$ $\mathit I{}^{G}(\mathit J{}^{PC}) = 1{}^{-}(?{}^{?+})$
MASS ${\mathrm {(MeV)}}$ WIDTH ${\mathrm {(MeV)}}$ DOCUMENT ID TECN CHG COMMENT
$1964 \pm35$ $225 \pm50$ 1
1993 D
E760 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ 3 ${{\mathit \pi}^{0}}$ $\rightarrow$ 6 ${{\mathit \gamma}}$
$\sim2100$ $\sim500$ 1
1977
CIBS - 25 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{-}}{{\mathit \rho}_{{3}}}$
$2214 \pm15$ $355 \pm21$ 2
1977
HBC 0 15 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Delta}^{++}}$3 ${{\mathit \pi}}$
$2080 \pm40$ $340 \pm80$
1975
HBC + 15 ${{\mathit \pi}^{+}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{+}}{{\mathit \rho}_{{3}}}$
1 Cannot determine spin to be 3.
2 BALTAY 1977 favors $\mathit J{}^{P}$.
References:
ARMSTRONG 1993D
PL B307 399 Production of the ${{\mathit f}_{{2}}{(1520)}}$ Resonance in Antiproton Proton Annihilation at $\sqrt {s }$ = 2980 and 3526 MeV
ANTIPOV 1977
NP B119 45 Boson States in the Reaction ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit p}}$ with Leading ${{\mathit \pi}^{+}}$ Meson at 25 ${\mathrm {GeV/}}\mathit c$
BALTAY 1977
PRL 39 591 Diffractive and Nondiffractive ${{\mathit A}_{{1}}}$ , ${{\mathit A}_{{3}}}$ and ${{\mathit A}_{{4}}}$ Production in ${{\mathit \pi}^{+}}{{\mathit p}}$ Interactions at 15 ${\mathrm {GeV/}}\mathit c$
KALELKAR 1975
Thesis Nevis 207 Meson Resonance Production in 15 ${\mathrm {GeV/}}\mathit c$ ${{\mathit \pi}^{+}}$ Interactions with Liquid Hydrogen
| 2023-03-31T12:39:04 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7116803526878357, "perplexity": 4172.497731056212}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949642.35/warc/CC-MAIN-20230331113819-20230331143819-00305.warc.gz"}
|
https://www.conicet.gov.ar/new_scp/detalle.php?keywords=&id=13074&inst=yes&congresos=yes&detalles=yes&congr_id=977185
|
IFLP 13074
INSTITUTO DE FISICA LA PLATA
congresos y reuniones científicas
Título:
Modulation spectroscopy with ultracold atoms loaded in optical lattice
Autor/es:
ANIBAL IUCCI
Lugar:
Malargüe
Reunión:
Congreso; 95a Reunión de la Asociación Física Argentina; 2010
The experimental realization of the regime of quantum degeneracy with weakly interacting ultracold atoms opened the way to numerous exciting experiments directly probing fundamental effects of quantum mechanics. In addition, the remarkable control on the parameters reached in cold atoms loaded in optical lattices setups led to employ out of equilibrium processes to increase the ability to probe the properties of these systems. In this talk we shall present the analysis of an experimental technique for probing ultracold atoms in an optical lattices by periodic lattice depth modulations. We find that for bosons, sharp energy absorption peaks are not unique to the Mott insulating phase at commensurate filling but also exist for superfluids at incommensurate filling. For strong interactions, the peak structure provides an experimental measure of the interaction strength. Moreover, the peak height of the peaks at $\hbar\omega\gtrsim 2U$ can be employed as a measure of the incommensurability of the system. For fermions, the lattice modulation produces double occupied sites. The spectrum of the induced double occupancy allows to determine the pairing gap in a superfluid state and the interaction energy in the Mott-insulator.
| 2020-04-10T06:18:25 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3267632722854614, "perplexity": 1491.5015225439302}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585371886991.92/warc/CC-MAIN-20200410043735-20200410074235-00094.warc.gz"}
|
https://dlmf.nist.gov/24.9
|
# §24.9 Inequalities
Except where otherwise noted, the inequalities in this section hold for $n=1,2,\dotsc$.
24.9.1 $\displaystyle|B_{2n}|$ $\displaystyle>|B_{2n}\left(x\right)|,$ $1>x>0$, ⓘ Symbols: $B_{\NVar{n}}$: Bernoulli numbers, $B_{\NVar{n}}\left(\NVar{x}\right)$: Bernoulli polynomials, $n$: integer and $x$: real or complex A&S Ref: 23.1.13 Referenced by: §24.9 Permalink: http://dlmf.nist.gov/24.9.E1 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24 24.9.2 $\displaystyle(2-2^{1-2n})|B_{2n}|$ $\displaystyle\geq|B_{2n}\left(x\right)-B_{2n}|,$ $1\geq x\geq 0$. ⓘ Symbols: $B_{\NVar{n}}$: Bernoulli numbers, $B_{\NVar{n}}\left(\NVar{x}\right)$: Bernoulli polynomials, $n$: integer and $x$: real or complex Referenced by: §24.9 Permalink: http://dlmf.nist.gov/24.9.E2 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
(24.9.3)–(24.9.5) hold for $\tfrac{1}{2}>x>0$.
24.9.3 $\displaystyle 4^{-n}|E_{2n}|$ $\displaystyle>(-1)^{n}E_{2n}\left(x\right)>0,$ ⓘ Symbols: $E_{\NVar{n}}$: Euler numbers, $E_{\NVar{n}}\left(\NVar{x}\right)$: Euler polynomials, $n$: integer and $x$: real or complex A&S Ref: 23.1.13 Referenced by: §24.9, §24.9 Permalink: http://dlmf.nist.gov/24.9.E3 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24 24.9.4 $\displaystyle\frac{2(2n+1)!}{(2\pi)^{2n+1}}$ $\displaystyle>(-1)^{n+1}B_{2n+1}\left(x\right)>0,$ $n=2,3,\dots$, 24.9.5 $\displaystyle\frac{4(2n-1)!}{\pi^{2n}}\frac{2^{2n}-1}{2^{2n}-2}$ $\displaystyle>(-1)^{n}E_{2n-1}\left(x\right)>0.$ ⓘ Symbols: $E_{\NVar{n}}\left(\NVar{x}\right)$: Euler polynomials, $\pi$: the ratio of the circumference of a circle to its diameter, $!$: factorial (as in $n!$), $n$: integer and $x$: real or complex A&S Ref: 23.1.14 Referenced by: §24.9, §24.9 Permalink: http://dlmf.nist.gov/24.9.E5 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
(24.9.6)–(24.9.7) hold for $n=2,3,\dotsc$.
24.9.6 $5\sqrt{\pi n}\left(\frac{n}{\pi e}\right)^{2n}>(-1)^{n+1}B_{2n}>4\sqrt{\pi n}% \left(\frac{n}{\pi e}\right)^{2n},$ ⓘ Symbols: $B_{\NVar{n}}$: Bernoulli numbers, $\pi$: the ratio of the circumference of a circle to its diameter, $\mathrm{e}$: base of natural logarithm and $n$: integer Referenced by: §24.9, §24.9 Permalink: http://dlmf.nist.gov/24.9.E6 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
24.9.7 $8\sqrt{\frac{n}{\pi}}\left(\frac{4n}{\pi e}\right)^{2n}\left(1+\frac{1}{12n}% \right)>(-1)^{n}E_{2n}>8\sqrt{\frac{n}{\pi}}\left(\frac{4n}{\pi e}\right)^{2n}.$ ⓘ Symbols: $E_{\NVar{n}}$: Euler numbers, $\pi$: the ratio of the circumference of a circle to its diameter, $\mathrm{e}$: base of natural logarithm and $n$: integer Referenced by: §24.9, §24.9 Permalink: http://dlmf.nist.gov/24.9.E7 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
Lastly,
24.9.8 $\frac{2(2n)!}{(2\pi)^{2n}}\frac{1}{1-2^{\beta-2n}}\geq(-1)^{n+1}B_{2n}\geq% \frac{2(2n)!}{(2\pi)^{2n}}\frac{1}{1-2^{-2n}}$
with
24.9.9 $\beta=2+\frac{\ln\left(1-6\pi^{-2}\right)}{\ln 2}=0.6491\dots.$ ⓘ Symbols: $\pi$: the ratio of the circumference of a circle to its diameter, $\ln\NVar{z}$: principal branch of logarithm function and $\beta$: quantity Permalink: http://dlmf.nist.gov/24.9.E9 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
24.9.10 $\frac{4^{n+1}(2n)!}{\pi^{2n+1}}>(-1)^{n}E_{2n}>\frac{4^{n+1}(2n)!}{\pi^{2n+1}}% \frac{1}{1+3^{-1-2n}}.$ ⓘ Symbols: $E_{\NVar{n}}$: Euler numbers, $\pi$: the ratio of the circumference of a circle to its diameter, $!$: factorial (as in $n!$) and $n$: integer A&S Ref: 23.1.15 Referenced by: §24.9 Permalink: http://dlmf.nist.gov/24.9.E10 Encodings: TeX, pMML, png See also: Annotations for §24.9 and Ch.24
| 2021-02-25T18:44:01 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 68, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9492619633674622, "perplexity": 14886.828778566878}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178351454.16/warc/CC-MAIN-20210225182552-20210225212552-00003.warc.gz"}
|
https://pages.nist.gov/feasst/plugin/monte_carlo/doc/TrialComputeMove.html
|
# TrialComputeMove¶
class TrialComputeMove : public feasst::TrialCompute
Move a selection of particles and sites.
Derivation of the acceptance criteria follows Lecture 9 of Prof. David Kofke’s Molecular Simulation course CE 530.
http://www.eng.buffalo.edu/~kofke/ce530/Lectures/lectures.html
For this type of move, the potential energy of the system, U, is the only thermodynamic variable which changes. Thus, whether in the canonical ensemble or otherwise, the probability distribution,
$$\pi_i \propto e^{-\beta U_i}$$
because the other thermodynamic variables such as number of particles, or volume do not change.
The following table describes the transition probabilities associated with the chosen trial move, and its reverse trial that is considered for the purpose of satisfying detailed balance. Thus, the probability shown represents the probability of transitioning from the old to the new state, $$\pi_{on}$$. And the reverse transition probability is from new to old, $$\pi_{no}$$.
Forward event [reverse event] Probability, $$\pi_{on}$$ [reverse probability, $$\pi_{no}$$] Select molecule of type t [Select molecule of type t] $$1/N_t$$ $$[1/N_t]$$ Move to new position [Move to old position] $$1/v$$ $$[1/v]$$ Accept [Accept] $$min(1, \chi)$$ $$[min(1, 1/\chi)]$$
where $$\chi$$ is the acceptance probability that we can now derive by imposing the (local) detailed balance condition.
For (local) detailed balance, the probability of being in the old state, $$\pi_o$$, times the probability of transitioning from the old to the new state, $$\pi_{on}$$, should be equal to the probability of being in the new state, $$\pi_n$$ times the probability of transitioning from the new to old state, $$\pi_{no}$$.
$$\pi_o \pi_{on} = \pi_n \pi_{no}$$
Substituting the probability distribution and transition probabilities yields
$$\frac{e^{-\beta U_o}min(1, \chi)}{N_t v} = \frac{e^{-\beta U_n}min(1, 1/\chi)}{N_t v}$$
$$min(1, \chi)/min(1, 1/\chi) = e^{-\beta(U_n - U_o)} = e^{-\beta\Delta U}$$
The left hand side is $$\chi$$ for both cases of $$\chi <= 1$$ and $$\chi > 1$$. Thus,
$$\chi = e^{-\beta\Delta U}$$
Subclassed by feasst::ComputeAVB2, feasst::ComputeAVB4
Public Functions
void perturb_and_acceptance(Criteria *criteria, System *system, Acceptance *acceptance, std::vector<TrialStage*> *stages, Random *random)
Perform the Perturbations and determine acceptance.
| 2021-02-28T01:44:27 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6604546904563904, "perplexity": 1271.4914427617828}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178359624.36/warc/CC-MAIN-20210227234501-20210228024501-00030.warc.gz"}
|
http://roderic.uv.es/handle/10550/53343
|
Correlated neutral beta meson decays into CP eigenstates
NAGIOS: RODERIC FUNCIONANDO
Correlated neutral beta meson decays into CP eigenstates
Visualització (167.2Kb)
Álvarez, Ezequiel; Bernabeu, J. (José) Perfil Aquest document és un/a article, creat/da en: 2004 In the two correlated B meson decay experiment we propose to measure intensities relating CP eigenstate (J/ψKS,L) decays on both sides, which will be measurable in future upgrades of KEK and PEP. As a CP-forbidden transition, we obtain I(J/ψKS,J/ψKS,Δt)∼sin2(2β). We calculate in a model independent way all the possible intensities relating final CP and flavour eigenstate decays. Under CPT-invariance, the asymmetries for processes related by CPΔt vanish for ΔΓ=0 and measure ΔΓ linearly. We notice the impossibility to isolate the sign of $\cos (2\bet a)$ without an independent knowledge of the sign of ΔΓ. This exhaustion of the possible Golden Plate and flavour decays provides new observables which may throw light in our present understanding of CKM physics. Álvarez, Ezequiel Bernabeu, J. (José) 2004 Correlated neutral beta meson decays into CP eigenstates Physics Letters B 579 1-2 79 85 http://dx.doi.org/10.1016/j.physletb.2003.10.114
distribuït sota llicència Creative Commons de Reconeixement-NoComercial 3.0 No adaptada
| 2017-03-27T14:48:53 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8815621137619019, "perplexity": 13877.013377268291}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218189474.87/warc/CC-MAIN-20170322212949-00215-ip-10-233-31-227.ec2.internal.warc.gz"}
|
https://lammps.sandia.gov/doc/Errors_common.html
|
# 13.1. Common problems
If two LAMMPS runs do not produce the exact same answer on different machines or different numbers of processors, this is typically not a bug. In theory you should get identical answers on any number of processors and on any machine. In practice, numerical round-off can cause slight differences and eventual divergence of molecular dynamics phase space trajectories within a few 100s or few 1000s of timesteps. However, the statistical properties of the two runs (e.g. average energy or temperature) should still be the same.
If the velocity command is used to set initial atom velocities, a particular atom can be assigned a different velocity when the problem is run on a different number of processors or on different machines. If this happens, the phase space trajectories of the two simulations will rapidly diverge. See the discussion of the loop option in the velocity command for details and options that avoid this issue.
Similarly, the create_atoms command generates a lattice of atoms. For the same physical system, the ordering and numbering of atoms by atom ID may be different depending on the number of processors.
Some commands use random number generators which may be setup to produce different random number streams on each processor and hence will produce different effects when run on different numbers of processors. A commonly-used example is the fix langevin command for thermostatting.
A LAMMPS simulation typically has two stages, setup and run. Most LAMMPS errors are detected at setup time; others like a bond stretching too far may not occur until the middle of a run.
LAMMPS tries to flag errors and print informative error messages so you can fix the problem. For most errors it will also print the last input script command that it was processing. Of course, LAMMPS cannot figure out your physics or numerical mistakes, like choosing too big a timestep, specifying erroneous force field coefficients, or putting 2 atoms on top of each other! If you run into errors that LAMMPS doesn’t catch that you think it should flag, please send an email to the developers.
If you get an error message about an invalid command in your input script, you can determine what command is causing the problem by looking in the log.lammps file or using the echo command to see it on the screen. If you get an error like “Invalid … style”, with … being fix, compute, pair, etc, it means that you mistyped the style name or that the command is part of an optional package which was not compiled into your executable. The list of available styles in your executable can be listed by using the -h command-line swith. The installation and compilation of optional packages is explained on the Build packages doc page.
For a given command, LAMMPS expects certain arguments in a specified order. If you mess this up, LAMMPS will often flag the error, but it may also simply read a bogus argument and assign a value that is valid, but not what you wanted. E.g. trying to read the string “abc” as an integer value of 0. Careful reading of the associated doc page for the command should allow you to fix these problems. In most cases, where LAMMPS expects to read a number, either integer or floating point, it performs a stringent test on whether the provided input actually is an integer or floating-point number, respectively, and reject the input with an error message (for instance, when an integer is required, but a floating-point number 1.0 is provided):
ERROR: Expected integer parameter instead of '1.0' in input script or data file
Some commands allow for using variable references in place of numeric constants so that the value can be evaluated and may change over the course of a run. This is typically done with the syntax v_name for a parameter, where name is the name of the variable. On the other hand, immediate variable expansion with the syntax \$name is performed while reading the input and before parsing commands,
Note
Using a variable reference (i.e. v_name) is only allowed if the documentation of the corresponding command explicitly says it is. Otherwise, you will receive an error message of this kind:
ERROR: Expected floating point parameter instead of 'v_name' in input script or data file
Generally, LAMMPS will print a message to the screen and logfile and exit gracefully when it encounters a fatal error. Sometimes it will print a WARNING to the screen and logfile and continue on; you can decide if the WARNING is important or not. A WARNING message that is generated in the middle of a run is only printed to the screen, not to the logfile, to avoid cluttering up thermodynamic output. If LAMMPS crashes or hangs without spitting out an error message first then it could be a bug (see this section) or one of the following cases:
LAMMPS runs in the available memory a processor allows to be allocated. Most reasonable MD runs are compute limited, not memory limited, so this shouldn’t be a bottleneck on most platforms. Almost all large memory allocations in the code are done via C-style malloc’s which will generate an error message if you run out of memory. Smaller chunks of memory are allocated via C++ “new” statements. If you are unlucky you could run out of memory just when one of these small requests is made, in which case the code will crash or hang (in parallel), since LAMMPS doesn’t trap on those errors.
Illegal arithmetic can cause LAMMPS to run slow or crash. This is typically due to invalid physics and numerics that your simulation is computing. If you see wild thermodynamic values or NaN values in your LAMMPS output, something is wrong with your simulation. If you suspect this is happening, it is a good idea to print out thermodynamic info frequently (e.g. every timestep) via the thermo so you can monitor what is happening. Visualizing the atom movement is also a good idea to insure your model is behaving as you expect.
In parallel, one way LAMMPS can hang is due to how different MPI implementations handle buffering of messages. If the code hangs without an error message, it may be that you need to specify an MPI setting or two (usually via an environment variable) to enable buffering or boost the sizes of messages that can be buffered.
| 2019-06-18T20:55:11 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.36033082008361816, "perplexity": 1006.6997341276102}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627998817.58/warc/CC-MAIN-20190618203528-20190618225528-00270.warc.gz"}
|
https://www.zbmath.org/authors/?q=ai%3Ajager.willi
|
## Jäger, Willi
Compute Distance To:
Author ID: jager.willi Published as: Jäger, Willi; Jäger, W. Homepage: http://www.iwr.uni-heidelberg.de/groups/amj/People/Willi.Jaeger/Contents.php External Links: MGP · Wikidata · Math-Net.Ru · dblp · GND
Documents Indexed: 98 Publications since 1967 22 Contributions as Editor · 1 Further Contribution Biographic References: 3 Publications Co-Authors: 95 Co-Authors with 110 Joint Publications 2,293 Co-Co-Authors
all top 5
### Co-Authors
9 single-authored 15 Neuss-Radu, Maria 14 Mikelić, Andro 7 Shaposhnikova, Tatiana A. 6 Krause, Egon Hermann Emil 5 Oleĭnik, Ol’ga Arsen’evna 4 Bock, Hans Georg 4 Ivanov, Aleksandr Vasil’evich 4 Kacur, Jozef 4 Simon, László 4 Wittum, Gabriel 3 An, Le Thi Thanh 3 Capasso, Vincenzo 3 Gurevich, Pavel L. 3 Hornung, Ulrich 3 Kaul, Helmut 3 Mkrtychyan, P. Z. 3 Rannacher, Rolf 3 Rejto, Peter 3 Resch, Michael M. 3 Saitō, Yoshimi 3 Tang, Betty K. P. 2 Antonić, Nenad 2 Chavarría Krauser, Andrés 2 Chuai-Aree, Somporn 2 Hoàng Xuân Phù 2 Hoppensteadt, Frank C. 2 Krebs, Hans-Joachim 2 Krömker, Susanne 2 Lax, Peter David 2 Lu, Yunguang 2 Nagel, Wolfgang E. 2 Neuss, Nicolas 2 Ptashnyk, Mariya 2 Schlöder, Johannes P. 2 Shamaev, Alexei S. 2 Siripant, Suchada 2 Skubachevskiĭ, Aleksandr Leonidovich 2 Synge Morawetz, Cathleen 2 van Duijn, Cornelis Johannes 2 Wagner, Christian 1 Bastian, Peter 1 Bocharov, Gennady A. 1 Carraro, Thomas 1 Chiu, Chichia 1 Engwer, Christian 1 Gahn, Markus 1 Helmig, Rainer 1 Hildebrandt, Stefan 1 Hoffmann, Karl-Heinz 1 John, Oldřich 1 Kinzelbach, Wolfgang 1 Kirkilionis, Markus A. 1 Knabner, Peter 1 Knoch, Jonas 1 Kohlmeier, Eberhard 1 Kopfer, Kai H. 1 Körkel, Stefan 1 Kühnle, J. 1 Lang, Serge 1 Le Thi Thanh An 1 Lohmann, Thomas Wilhelm 1 Luckhaus, Stephan 1 Ludwig, Stephan Ernst 1 Marnach, Sven 1 Marušić-Paloka, Eduard 1 Matthäus, Franziska 1 Mercker, Moritz 1 Morale, Daniela 1 Moser, Jürgen K. 1 Najzar, Karel 1 Nečas, Jindřich 1 Noori, Hamid Reza 1 Postel, Marie 1 Quien, Norbert 1 Remmert, Reinhold W. 1 Rost, Hermann 1 Sager, Sebastian 1 Sauvigny, Friedrich 1 Schmitt, Klaus 1 Schunck, Hermann 1 Sepúlveda, Mauricio A. 1 Smith, Hal Leslie 1 So, Joseph Wai-Hung 1 Stará, Jana 1 Tambulea, Adela 1 Tautu, Petre 1 Thiel, Manfred 1 Tomi, Friedrich 1 Törner, Günter 1 Valentin, Patrick 1 Waltman, Paul Elvis 1 Warnatz, Jürgen 1 Weller, Frédéric Frank 1 Willershausen, Harald 1 Wirth, James F. 1 Woukeng, Jean Louis 1 Yang, Yifan 1 Yong, Wen-An 1 Zanella, Mattia
all top 5
### Serials
6 Journal of Differential Equations 5 Mathematische Zeitschrift 5 Journal of Mathematical Sciences (New York) 4 Journal of Mathematical Biology 4 SIAM Journal on Mathematical Analysis 3 Journal of Mathematical Analysis and Applications 3 Doklady Mathematics 3 Vietnam Journal of Mathematics 3 Nonlinear Analysis. Real World Applications 3 Journal of Theoretical Biology 2 Archive for Rational Mechanics and Analysis 2 Communications on Pure and Applied Mathematics 2 Nachrichten der Akademie der Wissenschaften in Göttingen. II. Mathematisch-Physikalische Klasse 2 Transactions of the Moscow Mathematical Society 2 Acta Mathematica Hungarica 2 RAIRO. Modélisation Mathématique et Analyse Numérique 2 Computing and Visualization in Science 1 Applicable Analysis 1 Communications in Mathematical Physics 1 Jahresbericht der Deutschen Mathematiker-Vereinigung (DMV) 1 Mathematical Biosciences 1 Mitteilungen der Deutschen Mathematiker-Vereinigung (DMV) 1 Bulletin of Mathematical Biology 1 Reviews in Mathematical Physics 1 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 1 Annales Universitatis Scientiarum Budapestinensis de Rolando Eötvös Nominatae. Sectio Mathematica 1 Computing 1 Journal of Computational and Applied Mathematics 1 Journal für die Reine und Angewandte Mathematik 1 Manuscripta Mathematica 1 Mathematische Annalen 1 Numerische Mathematik 1 Osaka Journal of Mathematics 1 Studia Scientiarum Mathematicarum Hungarica 1 Transactions of the American Mathematical Society 1 Forum Mathematicum 1 SIAM Journal on Applied Mathematics 1 Notices of the American Mathematical Society 1 Journal of Dynamics and Differential Equations 1 SIAM Journal on Scientific Computing 1 Russian Academy of Sciences. Doklady. Mathematics 1 Zapiski Nauchnykh Seminarov POMI 1 East-West Journal of Mathematics 1 Differential Equations 1 Multiscale Modeling & Simulation 1 Lecture Notes in Biomathematics 1 Chapman & Hall/CRC Research Notes in Mathematics 1 Contributions in Mathematical and Computational Sciences
all top 5
### Fields
67 Partial differential equations (35-XX) 30 Fluid mechanics (76-XX) 28 Biology and other natural sciences (92-XX) 20 Numerical analysis (65-XX) 19 General and overarching topics; collections (00-XX) 12 Computer science (68-XX) 8 Mechanics of deformable solids (74-XX) 7 Quantum theory (81-XX) 6 History and biography (01-XX) 6 Systems theory; control (93-XX) 5 Ordinary differential equations (34-XX) 3 Dynamical systems and ergodic theory (37-XX) 3 Operator theory (47-XX) 3 Classical thermodynamics, heat transfer (80-XX) 3 Relativity and gravitational theory (83-XX) 2 Integral equations (45-XX) 2 Calculus of variations and optimal control; optimization (49-XX) 2 Differential geometry (53-XX) 2 Global analysis, analysis on manifolds (58-XX) 2 Statistical mechanics, structure of matter (82-XX) 1 Real functions (26-XX) 1 Potential theory (31-XX) 1 Functional analysis (46-XX) 1 Algebraic topology (55-XX) 1 Probability theory and stochastic processes (60-XX) 1 Statistics (62-XX) 1 Optics, electromagnetic theory (78-XX) 1 Geophysics (86-XX) 1 Operations research, mathematical programming (90-XX)
### Citations contained in zbMATH Open
72 Publications have been cited 1,488 times in 1,247 Documents Cited by Year
On explosions of solutions to a system of partial differential equations modelling chemotaxis. Zbl 0746.35002
Jäger, W.; Luckhaus, S.
1992
On the interface boundary condition of Beavers, Joseph, and Saffman. Zbl 0969.76088
Jäger, Willi; Mikelic, Andro
2000
On the roughness-induced effective boundary conditions for an incompressible viscous flow. Zbl 1009.76017
Jäger, Willi; Mikelić, Andro
2001
Uniqueness and stability of harmonic maps and their Jacobi fields. Zbl 0413.31006
Jäger, Willi; Kaul, Helmut
1979
Diffusion, convection, adsorption, and reaction of chemicals in porous media. Zbl 0731.76080
Hornung, Ulrich; Jäger, Willi
1991
On the boundary conditions at the contact interface between a porous medium and a free fluid. Zbl 0878.76076
Jäger, Willi; Mikelić, Andro
1996
Effective transmission conditions for reaction-diffusion processes in domains separated by an interface. Zbl 1145.35017
2007
Rotationally symmetric harmonic maps from a ball into a sphere and the regularity problem for weak solutions of elliptic systems. Zbl 0516.35032
Jäger, Willi; Kaul, Helmut
1983
Asymptotic analysis of the laminar viscous flow over a porous bed. Zbl 0980.35124
Jäger, Willi; Mikelic, Andro; Neuss, Nicolas
2001
Zur Theorie der Schwingungsgleichung mit variablen Koeffizienten in Außengebieten. Zbl 0162.16402
Jäger, W.
1967
Couette flows over a rough boundary and drag reduction. Zbl 1062.76012
Jäger, Willi; Mikelić, Andro
2003
Behavior of minimal surfaces with free boundaries. Zbl 0204.11601
Jäger, W.
1970
Solution of doubly nonlinear and degenerate parabolic problems by relaxation schemes. Zbl 0837.65103
Jäger, W.; Kačur, J.
1995
Reactive transport through an array of cells with semi-permeable membranes. Zbl 0824.76083
Hornung, U.; Jäger, W.; Mikelić, A.
1994
Solution of porous medium type systems by linear approximation schemes. Zbl 0744.65060
Jäger, Willi; Kačur, Jozef
1991
Competition in the gradostat. Zbl 0643.92021
Jäger, W.; So, Joseph W.-H.; Tang, Betty; Waltman, Paul
1987
Ein gewöhnlicher Differentialoperator zweiter Ordnung für Funktionen mit Werten in einem Hilbertraum. Zbl 0187.09001
Jäger, W.
1970
Homogenization of a variational inequality for the Laplace operator with nonlinear restriction for the flux on the interior boundary of a perforated domain. Zbl 1295.35048
Jäger, Willi; Neuss-Radu, Maria; Shaposhnikova, Tatiana A.
2014
Homogenization and multigrid. Zbl 0992.35013
Neuss, N.; Jäger, W.; Wittum, G.
2001
Uniqueness of harmonic mappings and of solutions of elliptic equations on Riemannian manifolds. Zbl 0388.58002
Jäger, Willi; Kaul, Helmut
1979
Über das Dirichletsche Außenraumproblem für die Schwingungsgleichung. Zbl 0144.15402
Jäger, W.
1967
On solutions to nonlinear reaction-diffusion-convection equations with degenerate diffusion. Zbl 0977.35068
Lu, Yunguang; Jäger, Willi
2001
Mathematical modeling and simulation of the evolution of plaques in blood vessels. Zbl 1343.35190
Yang, Yifan; Jäger, Willi; Neuss-Radu, Maria; Richter, Thomas
2016
Global regularity of solution for general degenerate parabolic equations in 1-D. Zbl 0915.35047
Jäger, W.; Lu, Yunguang
1997
Pattern formation by bacteria. Zbl 0437.92023
1980
Quiescence and transient growth dynamics in chemostat models. Zbl 0799.92022
Jäger, Willi; Krömker, Susanne; Tang, Betty
1994
Ein Maximumprinzip für ein System nichtlinearer Differentialgleichungen. Zbl 0362.35030
Jäger, Willi
1976
Das asymptotische Verhalten von Lösungen eines Typs von Differentialgleichungen. Zbl 0185.17902
Jäger, W.
1969
On the regularity of surfaces with prescribed man curvature at a free boundary. Zbl 0204.11504
Hildebrandt, S.; Jäger, W.
1970
On periodicity of solutions for thermocontrol problems with hysteresis-type switches. Zbl 1192.35012
Gurevich, P.; Jäger, W.; Skubachevskii, A.
2009
Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for a class of doubly nonlinear parabolic equations. Zbl 0872.35055
Ivanov, A. V.; Mkrtychyan, P. Z.; Jäger, W.
1994
Homogenization limit of a model system for interaction of flow, chemical reactions, and mechanics in cell tissues. Zbl 1226.93016
Jäger, Willi; Mikelić, Andro; Neuss-Radu, Maria
2011
Multiscale analysis and simulation of a reaction-diffusion problem with transmission conditions. Zbl 1228.35030
Neuss-Radu, Maria; Ludwig, Stephan; Jäger, Willi
2010
Remarks on results of Heinz concerning the continuity of total variations. Zbl 0201.13802
Jäger, W.
1970
Limiting absorption principle for some Schrödinger operators with exploding potentials. I. Zbl 0533.35018
Jäger, Willi; Rejto, Peter
1983
A multiscale approach to curvature modulated sorting in biological membranes. Zbl 1397.92062
Mercker, M.; Ptashnyk, M.; Kühnle, J.; Hartmann, D.; Weiss, M.; Jäger, W.
2012
Analysis and computer simulation of accretion patterns in bacterial cultures. Zbl 0808.92010
Chiu, Chichia; Hoppensteadt, Frank C.; Jäger, Willi
1994
Homogenization limit for the diffusion equation with nonlinear flux condition on the boundary of very thin holes periodically distributed in a domain, in case of a critical size. Zbl 1213.35061
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2010
Analysis of differential equations modelling the reactive flow through a deformable system of cells. Zbl 1160.74034
Jäger, Willi; Mikelić, Andro; Neuss-Radu, Maria
2009
On the effective equations of a viscous incompressible fluid flow through a filter of finite thickness. Zbl 0938.76101
Jäger, Willi; Mikelić, Andro
1998
Erratum to: “Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for a class of doubly nonlinear parabolic equations”. Zbl 1252.35161
Ivanov, A. V.; Mkrtychan, P. Z.; Jäger, Willi
2012
Parabolic problems with the Preisach hysteresis operator in boundary conditions. Zbl 1180.35120
Gurevich, Pavel; Jäger, Willi
2009
On a system of quasliniear parabolic functional differential equations. Zbl 1121.35138
Jäger, W.; Simon, L.
2006
Homogenization of solutions of the Poisson equation in a domain perforated along a hypersurface, with mixed boundary conditions on the boundary of the cavities. Zbl 0921.35015
Jäger, W.; Oleinik, O. A.; Shaposhnikova, T. A.
1998
On homogenization of solutions of the Poisson equation in a perforated domain with different types of boundary conditions on different cavities. Zbl 0903.35005
Jäger, W.; Oleinik, O. A.; Shaposhnikova, T. A.
1997
Existence and uniqueness of a regular solution of the first initial-boundary value problem for a certain class of doubly nonlinear parabolic equations. Zbl 0868.35060
Ivanov, A. V.; Mkrtychyan, P. Z.; Jäger, W.
1994
Generic failure of persistence and equilibrium coexistence in a model of $$m$$-species competition in an $$n$$-vessel gradostat when $$m>n$$. Zbl 0745.92027
Jäger, Willi; Smith, Hal; Tang, Betty
1991
Limiting absorption principle for some Schrödinger operators with exploding potentials. II. Zbl 0533.35019
Jäger, Willi; Rejto, Peter
1983
Multiscale problems in science and technology. Challenges to mathematical analysis and perspectives. Proceedings of the conference on multiscale problems in science and technology, Dubrovnik, Croatia, September 3–9, 2000. Zbl 0989.00039
2002
On the flow conditions at the boundary between a porous medium and an impervious solid. Zbl 0840.35083
Jäger, W.; Mikelić, A.
1994
On transmission problems for nonlinear parabolic differential equations. Zbl 1049.35105
Jäger, W.; Simon, L.
2002
Homogenization of the diffusion equation with nonlinear flux condition on the interior boundary of a perforated domain – the influence of the scaling on the nonlinearity in the effective sink-source term. Zbl 1291.35112
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2011
Asymptotics of solutions of the boundary value problem for the Laplace equation in a partially perforated domain with boundary conditions of the third kind on the boundaries of the cavities. Zbl 0902.35012
Jäger, W.; Oleinik, O. A.; Shamaev, A. S.
1997
Mathematics – key technology for the future. Joint projects between universities and industry. Zbl 1016.00014
2003
Homogenization of the Laplace equation in a partially perforated domain. Zbl 1043.35030
Jäger, W.; Mikelić, A.
1999
On non-uniformly parabolic functional differential equations. Zbl 1174.35054
Simon, László; Jäger, Willi
2008
On the existence of periodic solutions to some nonlinear thermal control problems. Zbl 1151.93020
Gurevich, P. L.; Jäger, W.; Skubachevskii, A. L.
2008
Homogenization of reactive transport through porous media. Zbl 0938.76586
Hornung, Ulrich; Jäger, Willi
1993
Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for the equation of turbulent filtration. Zbl 0957.35067
Ivanov, A. V.; Jäger, W.
1997
Systems of populations with multiple structures: modeling and analysis. Zbl 1342.92182
Le Thi Thanh An; Jäger, Willi; Neuss-Radu, Maria
2015
A quantitative model of population dynamics in malaria with drug treatment. Zbl 1302.34068
An, Le Thi Thanh; Jäger, Willi
2014
Scale limit of a variational inequality modeling diffusive flux in a domain with small holes and strong adsorption in case of a critical scaling. Zbl 1233.35104
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2011
Analysis of a free boundary problem modeling thrombus growth. Zbl 1304.35784
Weller, Frederic Frank; Neuss-Radu, Maria; Jäger, Willi
2013
Modelling in vitro growth of dense root networks. Zbl 1400.92333
Bastian, Peter; Chavarría-Krauser, Andrés; Engwer, Christian; Jäger, Willi; Marnach, Sven; Ptashnyk, Mariya
2008
Correctors and error estimates for reaction-diffusion processes through thin heterogeneous layers in case of homogenized equations with interface diffusion. Zbl 1450.35038
Gahn, Markus; Jäger, Willi; Neuss-Radu, Maria
2021
The uniqueness of the solution of the Schrödinger equation with discontinuous coefficients. Zbl 0924.35185
Jäger, Willi; Saitō, Yoshimi
1998
On the spectrum of the reduced wave operator with cylindrical discontinuity. Zbl 0870.35071
Jäger, Willi; Saitō, Yoshimi
1997
The reduced wave equation in layered materials. Zbl 0891.35026
Jäger, Willi; Saitō, Yoshimi
1997
Model based parameter estimation. Theory and applications. Based on the workshop on parameter estimation, Heidelberg, Germany, 2009. Zbl 1261.65002
Bock, Hans Georg
2013
Das Randverhalten von Flächen beschränkter mittlerer Krümmung bei $$C^{1,\alpha}$$-Rändern. Zbl 0395.35028
Jäger, W.
1977
On the boundary conditions at the contact interface between two porous media. Zbl 0934.35135
Jäger, W.; Mikelić, A.
2000
On a theorem of Mochizuki and Uchiyama about long range oscillating potentials. I. Zbl 1008.35011
Jäger, W.; Rejto, P.
2000
Correctors and error estimates for reaction-diffusion processes through thin heterogeneous layers in case of homogenized equations with interface diffusion. Zbl 1450.35038
Gahn, Markus; Jäger, Willi; Neuss-Radu, Maria
2021
Mathematical modeling and simulation of the evolution of plaques in blood vessels. Zbl 1343.35190
Yang, Yifan; Jäger, Willi; Neuss-Radu, Maria; Richter, Thomas
2016
Systems of populations with multiple structures: modeling and analysis. Zbl 1342.92182
Le Thi Thanh An; Jäger, Willi; Neuss-Radu, Maria
2015
Homogenization of a variational inequality for the Laplace operator with nonlinear restriction for the flux on the interior boundary of a perforated domain. Zbl 1295.35048
Jäger, Willi; Neuss-Radu, Maria; Shaposhnikova, Tatiana A.
2014
A quantitative model of population dynamics in malaria with drug treatment. Zbl 1302.34068
An, Le Thi Thanh; Jäger, Willi
2014
Analysis of a free boundary problem modeling thrombus growth. Zbl 1304.35784
Weller, Frederic Frank; Neuss-Radu, Maria; Jäger, Willi
2013
Model based parameter estimation. Theory and applications. Based on the workshop on parameter estimation, Heidelberg, Germany, 2009. Zbl 1261.65002
Bock, Hans Georg
2013
A multiscale approach to curvature modulated sorting in biological membranes. Zbl 1397.92062
Mercker, M.; Ptashnyk, M.; Kühnle, J.; Hartmann, D.; Weiss, M.; Jäger, W.
2012
Erratum to: “Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for a class of doubly nonlinear parabolic equations”. Zbl 1252.35161
Ivanov, A. V.; Mkrtychan, P. Z.; Jäger, Willi
2012
Homogenization limit of a model system for interaction of flow, chemical reactions, and mechanics in cell tissues. Zbl 1226.93016
Jäger, Willi; Mikelić, Andro; Neuss-Radu, Maria
2011
Homogenization of the diffusion equation with nonlinear flux condition on the interior boundary of a perforated domain – the influence of the scaling on the nonlinearity in the effective sink-source term. Zbl 1291.35112
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2011
Scale limit of a variational inequality modeling diffusive flux in a domain with small holes and strong adsorption in case of a critical scaling. Zbl 1233.35104
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2011
Multiscale analysis and simulation of a reaction-diffusion problem with transmission conditions. Zbl 1228.35030
Neuss-Radu, Maria; Ludwig, Stephan; Jäger, Willi
2010
Homogenization limit for the diffusion equation with nonlinear flux condition on the boundary of very thin holes periodically distributed in a domain, in case of a critical size. Zbl 1213.35061
Jäger, W.; Neuss-Radu, M.; Shaposhnikova, T. A.
2010
On periodicity of solutions for thermocontrol problems with hysteresis-type switches. Zbl 1192.35012
Gurevich, P.; Jäger, W.; Skubachevskii, A.
2009
Analysis of differential equations modelling the reactive flow through a deformable system of cells. Zbl 1160.74034
Jäger, Willi; Mikelić, Andro; Neuss-Radu, Maria
2009
Parabolic problems with the Preisach hysteresis operator in boundary conditions. Zbl 1180.35120
Gurevich, Pavel; Jäger, Willi
2009
On non-uniformly parabolic functional differential equations. Zbl 1174.35054
Simon, László; Jäger, Willi
2008
On the existence of periodic solutions to some nonlinear thermal control problems. Zbl 1151.93020
Gurevich, P. L.; Jäger, W.; Skubachevskii, A. L.
2008
Modelling in vitro growth of dense root networks. Zbl 1400.92333
Bastian, Peter; Chavarría-Krauser, Andrés; Engwer, Christian; Jäger, Willi; Marnach, Sven; Ptashnyk, Mariya
2008
Effective transmission conditions for reaction-diffusion processes in domains separated by an interface. Zbl 1145.35017
2007
On a system of quasliniear parabolic functional differential equations. Zbl 1121.35138
Jäger, W.; Simon, L.
2006
Couette flows over a rough boundary and drag reduction. Zbl 1062.76012
Jäger, Willi; Mikelić, Andro
2003
Mathematics – key technology for the future. Joint projects between universities and industry. Zbl 1016.00014
2003
Multiscale problems in science and technology. Challenges to mathematical analysis and perspectives. Proceedings of the conference on multiscale problems in science and technology, Dubrovnik, Croatia, September 3–9, 2000. Zbl 0989.00039
2002
On transmission problems for nonlinear parabolic differential equations. Zbl 1049.35105
Jäger, W.; Simon, L.
2002
On the roughness-induced effective boundary conditions for an incompressible viscous flow. Zbl 1009.76017
Jäger, Willi; Mikelić, Andro
2001
Asymptotic analysis of the laminar viscous flow over a porous bed. Zbl 0980.35124
Jäger, Willi; Mikelic, Andro; Neuss, Nicolas
2001
Homogenization and multigrid. Zbl 0992.35013
Neuss, N.; Jäger, W.; Wittum, G.
2001
On solutions to nonlinear reaction-diffusion-convection equations with degenerate diffusion. Zbl 0977.35068
Lu, Yunguang; Jäger, Willi
2001
On the interface boundary condition of Beavers, Joseph, and Saffman. Zbl 0969.76088
Jäger, Willi; Mikelic, Andro
2000
On the boundary conditions at the contact interface between two porous media. Zbl 0934.35135
Jäger, W.; Mikelić, A.
2000
On a theorem of Mochizuki and Uchiyama about long range oscillating potentials. I. Zbl 1008.35011
Jäger, W.; Rejto, P.
2000
Homogenization of the Laplace equation in a partially perforated domain. Zbl 1043.35030
Jäger, W.; Mikelić, A.
1999
On the effective equations of a viscous incompressible fluid flow through a filter of finite thickness. Zbl 0938.76101
Jäger, Willi; Mikelić, Andro
1998
Homogenization of solutions of the Poisson equation in a domain perforated along a hypersurface, with mixed boundary conditions on the boundary of the cavities. Zbl 0921.35015
Jäger, W.; Oleinik, O. A.; Shaposhnikova, T. A.
1998
The uniqueness of the solution of the Schrödinger equation with discontinuous coefficients. Zbl 0924.35185
Jäger, Willi; Saitō, Yoshimi
1998
Global regularity of solution for general degenerate parabolic equations in 1-D. Zbl 0915.35047
Jäger, W.; Lu, Yunguang
1997
On homogenization of solutions of the Poisson equation in a perforated domain with different types of boundary conditions on different cavities. Zbl 0903.35005
Jäger, W.; Oleinik, O. A.; Shaposhnikova, T. A.
1997
Asymptotics of solutions of the boundary value problem for the Laplace equation in a partially perforated domain with boundary conditions of the third kind on the boundaries of the cavities. Zbl 0902.35012
Jäger, W.; Oleinik, O. A.; Shamaev, A. S.
1997
Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for the equation of turbulent filtration. Zbl 0957.35067
Ivanov, A. V.; Jäger, W.
1997
On the spectrum of the reduced wave operator with cylindrical discontinuity. Zbl 0870.35071
Jäger, Willi; Saitō, Yoshimi
1997
The reduced wave equation in layered materials. Zbl 0891.35026
Jäger, Willi; Saitō, Yoshimi
1997
On the boundary conditions at the contact interface between a porous medium and a free fluid. Zbl 0878.76076
Jäger, Willi; Mikelić, Andro
1996
Solution of doubly nonlinear and degenerate parabolic problems by relaxation schemes. Zbl 0837.65103
Jäger, W.; Kačur, J.
1995
Reactive transport through an array of cells with semi-permeable membranes. Zbl 0824.76083
Hornung, U.; Jäger, W.; Mikelić, A.
1994
Quiescence and transient growth dynamics in chemostat models. Zbl 0799.92022
Jäger, Willi; Krömker, Susanne; Tang, Betty
1994
Existence and uniqueness of a regular solution of the Cauchy-Dirichlet problem for a class of doubly nonlinear parabolic equations. Zbl 0872.35055
Ivanov, A. V.; Mkrtychyan, P. Z.; Jäger, W.
1994
Analysis and computer simulation of accretion patterns in bacterial cultures. Zbl 0808.92010
Chiu, Chichia; Hoppensteadt, Frank C.; Jäger, Willi
1994
Existence and uniqueness of a regular solution of the first initial-boundary value problem for a certain class of doubly nonlinear parabolic equations. Zbl 0868.35060
Ivanov, A. V.; Mkrtychyan, P. Z.; Jäger, W.
1994
On the flow conditions at the boundary between a porous medium and an impervious solid. Zbl 0840.35083
Jäger, W.; Mikelić, A.
1994
Homogenization of reactive transport through porous media. Zbl 0938.76586
Hornung, Ulrich; Jäger, Willi
1993
On explosions of solutions to a system of partial differential equations modelling chemotaxis. Zbl 0746.35002
Jäger, W.; Luckhaus, S.
1992
Diffusion, convection, adsorption, and reaction of chemicals in porous media. Zbl 0731.76080
Hornung, Ulrich; Jäger, Willi
1991
Solution of porous medium type systems by linear approximation schemes. Zbl 0744.65060
Jäger, Willi; Kačur, Jozef
1991
Generic failure of persistence and equilibrium coexistence in a model of $$m$$-species competition in an $$n$$-vessel gradostat when $$m>n$$. Zbl 0745.92027
Jäger, Willi; Smith, Hal; Tang, Betty
1991
Competition in the gradostat. Zbl 0643.92021
Jäger, W.; So, Joseph W.-H.; Tang, Betty; Waltman, Paul
1987
Rotationally symmetric harmonic maps from a ball into a sphere and the regularity problem for weak solutions of elliptic systems. Zbl 0516.35032
Jäger, Willi; Kaul, Helmut
1983
Limiting absorption principle for some Schrödinger operators with exploding potentials. I. Zbl 0533.35018
Jäger, Willi; Rejto, Peter
1983
Limiting absorption principle for some Schrödinger operators with exploding potentials. II. Zbl 0533.35019
Jäger, Willi; Rejto, Peter
1983
Pattern formation by bacteria. Zbl 0437.92023
1980
Uniqueness and stability of harmonic maps and their Jacobi fields. Zbl 0413.31006
Jäger, Willi; Kaul, Helmut
1979
Uniqueness of harmonic mappings and of solutions of elliptic equations on Riemannian manifolds. Zbl 0388.58002
Jäger, Willi; Kaul, Helmut
1979
Das Randverhalten von Flächen beschränkter mittlerer Krümmung bei $$C^{1,\alpha}$$-Rändern. Zbl 0395.35028
Jäger, W.
1977
Ein Maximumprinzip für ein System nichtlinearer Differentialgleichungen. Zbl 0362.35030
Jäger, Willi
1976
Behavior of minimal surfaces with free boundaries. Zbl 0204.11601
Jäger, W.
1970
Ein gewöhnlicher Differentialoperator zweiter Ordnung für Funktionen mit Werten in einem Hilbertraum. Zbl 0187.09001
Jäger, W.
1970
On the regularity of surfaces with prescribed man curvature at a free boundary. Zbl 0204.11504
Hildebrandt, S.; Jäger, W.
1970
Remarks on results of Heinz concerning the continuity of total variations. Zbl 0201.13802
Jäger, W.
1970
Das asymptotische Verhalten von Lösungen eines Typs von Differentialgleichungen. Zbl 0185.17902
Jäger, W.
1969
Zur Theorie der Schwingungsgleichung mit variablen Koeffizienten in Außengebieten. Zbl 0162.16402
Jäger, W.
1967
Über das Dirichletsche Außenraumproblem für die Schwingungsgleichung. Zbl 0144.15402
Jäger, W.
1967
all top 5
### Cited by 1,496 Authors
38 Winkler, Michael 29 Jäger, Willi 21 Shaposhnikova, Tatiana A. 20 Neuss-Radu, Maria 17 Mikelić, Andro 17 Mu, Chunlai 15 Tao, Youshan 14 Jost, Jürgen 14 Pop, Iuliu Sorin 13 Carrillo de la Plata, José Antonio 13 Muntean, Adrian 13 Ptashnyk, Mariya 13 Viglialoro, Giuseppe 11 Gérard-Varet, David 10 Chechkin, Gregory Aleksandrovich 10 Podolskii, Alexander V. 10 Zheng, Jiashan 9 Gahn, Markus 9 Gurevich, Pavel L. 9 Nitsche, Johannes Carl Christian 9 Quarteroni, Alfio M. 9 Zheng, Pan 9 Zheng, Sining 8 Calvez, Vincent 8 Diaz Diaz, Jesus Ildefonso 8 Discacciati, Marco 8 He, Xiaoming 8 Hildebrandt, Stefan 8 Kacur, Jozef 8 Kang, Kyungkeun 8 Knabner, Peter 8 Lankeit, Johannes 8 Nagai, Toshitaka 8 Radu, Florin Adrian 8 Wang, Xiaoming 7 Cieślak, Tomasz 7 Fardoun, Ali 7 Lin, Ke 7 Marušić-Paloka, Eduard 7 Oyarzúa, Ricardo 7 Smith, Hal Leslie 7 Wang, Yifu 6 Amirat, Youcef Aït 6 Feireisl, Eduard 6 Gadyl’shin, Rustem R. 6 Gatica, Gabriel N. 6 Gómez-Castro, David 6 Gómez, Delfina 6 Granero Belinchón, Rafael 6 Gunzburger, Max D. 6 Mallea-Zepeda, Exequiel 6 Mizoguchi, Noriko 6 Nečasová, Šárka 6 Ogawa, Takayoshi 6 Perthame, Benoît 6 Suzuki, Takashi 6 Velázquez, Juan J. L. 6 Xiang, Tian 6 Zubova, Maria N. 5 Allaire, Grégoire 5 Blanchet, Adrien 5 Brillard, Alain 5 Bucur, Dorin 5 Burczak, Jan 5 Cai, Mingchao 5 Chen, Qun 5 Di Francesco, Marco 5 Eggenweiler, Elissa 5 El Jarroudi, Mustapha 5 Fuest, Mario 5 Fujie, Kentarou 5 He, Siming 5 Hélein, Frédéric 5 Hu, Xuegang 5 Ijioma, Ekeoma Rowland 5 Kumar, Kundan 5 Marciniak-Czochra, Anna K. 5 Müller, Siegfried 5 Pažanin, Igor 5 Rybak, I. V. 5 Stevens, Angela 5 Sugiyama, Yoshie 5 Tomi, Friedrich 4 Ahn, Jaewook 4 Biler, Piotr 4 Bonnivard, Matthieu 4 Bresch, Didier 4 Čanić, Sunčica 4 Cao, Xinru 4 Carraro, Thomas 4 Chen, Li 4 Chen, Wenbin 4 Corrias, Lucilla 4 Dalibard, Anne-Laure 4 Deolmi, Giulia 4 Dziuk, Gerhard 4 Ervin, Vincent J. 4 Grüter, Michael 4 Hadeler, Karl-Peter 4 Hillen, Thomas ...and 1,396 more Authors
all top 5
### Cited in 241 Serials
81 Journal of Mathematical Analysis and Applications 57 Journal of Differential Equations 32 Nonlinear Analysis. Real World Applications 29 Archive for Rational Mechanics and Analysis 28 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 26 Journal of Computational and Applied Mathematics 25 Journal of Computational Physics 24 Mathematische Zeitschrift 23 Applicable Analysis 22 Mathematical Methods in the Applied Sciences 22 Manuscripta Mathematica 19 Computers & Mathematics with Applications 19 Calculus of Variations and Partial Differential Equations 18 Computer Methods in Applied Mechanics and Engineering 17 Journal of Functional Analysis 17 Discrete and Continuous Dynamical Systems. Series B 16 Numerische Mathematik 16 Journal of Mathematical Sciences (New York) 15 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 15 SIAM Journal on Mathematical Analysis 15 Discrete and Continuous Dynamical Systems 14 Journal of Scientific Computing 14 Journal of Mathematical Fluid Mechanics 13 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 13 Multiscale Modeling & Simulation 12 Mathematische Annalen 11 Journal of Mathematical Biology 11 Nonlinearity 11 ZAMP. Zeitschrift für angewandte Mathematik und Physik 11 Communications in Partial Differential Equations 11 Computational Geosciences 11 Comptes Rendus. Mathématique. Académie des Sciences, Paris 11 Communications on Pure and Applied Analysis 10 Journal of Fluid Mechanics 10 Applied Numerical Mathematics 10 Applied Mathematics Letters 10 Journal de Mathématiques Pures et Appliquées. Neuvième Série 10 SIAM Journal on Applied Mathematics 10 Discrete and Continuous Dynamical Systems. Series S 9 Communications in Mathematical Physics 9 Mathematical Biosciences 9 Applied Mathematics and Computation 9 Applications of Mathematics 9 Doklady Mathematics 9 Vietnam Journal of Mathematics 9 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 9 Nonlinear Analysis. Theory, Methods & Applications 8 Journal of Mathematical Physics 8 Mathematics of Computation 8 M2AN. Mathematical Modelling and Numerical Analysis. ESAIM, European Series in Applied and Industrial Mathematics 8 Journal of Evolution Equations 7 Inventiones Mathematicae 7 Quarterly of Applied Mathematics 7 Transactions of the American Mathematical Society 7 Acta Applicandae Mathematicae 6 Communications on Pure and Applied Mathematics 6 Annali di Matematica Pura ed Applicata. Serie Quarta 6 SIAM Journal on Numerical Analysis 6 The Journal of Geometric Analysis 6 Journal of Nonlinear Science 6 Networks and Heterogeneous Media 5 International Journal of Engineering Science 5 Rocky Mountain Journal of Mathematics 5 Applied Mathematics and Optimization 5 Archiv der Mathematik 5 Annals of Global Analysis and Geometry 5 Mathematical and Computer Modelling 5 European Journal of Applied Mathematics 5 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 5 Communications in Contemporary Mathematics 5 Advances in Nonlinear Analysis 4 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 4 Proceedings of the American Mathematical Society 4 Physica D 4 Numerical Methods for Partial Differential Equations 4 Journal of Elasticity 4 NoDEA. Nonlinear Differential Equations and Applications 4 Kinetic and Related Models 3 Computers and Fluids 3 Jahresbericht der Deutschen Mathematiker-Vereinigung (DMV) 3 Journal of Engineering Mathematics 3 Bulletin of Mathematical Biology 3 Reviews in Mathematical Physics 3 Acta Mathematica 3 Calcolo 3 Geometriae Dedicata 3 Integral Equations and Operator Theory 3 Monatshefte für Mathematik 3 Zeitschrift für Analysis und ihre Anwendungen 3 Asymptotic Analysis 3 Applied Mathematical Modelling 3 Journal of Dynamics and Differential Equations 3 Applied Mathematics. Series B (English Edition) 3 St. Petersburg Mathematical Journal 3 Computing and Visualization in Science 3 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 3 European Series in Applied and Industrial Mathematics (ESAIM): Proceedings 3 Oberwolfach Reports 3 Boundary Value Problems 3 Annali dell’Università di Ferrara. Sezione VII. Scienze Matematiche ...and 141 more Serials
all top 5
### Cited in 38 Fields
862 Partial differential equations (35-XX) 388 Biology and other natural sciences (92-XX) 378 Fluid mechanics (76-XX) 215 Numerical analysis (65-XX) 101 Global analysis, analysis on manifolds (58-XX) 88 Mechanics of deformable solids (74-XX) 77 Differential geometry (53-XX) 64 Calculus of variations and optimal control; optimization (49-XX) 44 Ordinary differential equations (34-XX) 40 Operator theory (47-XX) 26 Classical thermodynamics, heat transfer (80-XX) 22 Dynamical systems and ergodic theory (37-XX) 20 Statistical mechanics, structure of matter (82-XX) 15 Probability theory and stochastic processes (60-XX) 14 Quantum theory (81-XX) 13 Optics, electromagnetic theory (78-XX) 12 Geophysics (86-XX) 10 Systems theory; control (93-XX) 9 Functions of a complex variable (30-XX) 8 Functional analysis (46-XX) 7 Potential theory (31-XX) 7 Integral equations (45-XX) 4 General and overarching topics; collections (00-XX) 4 Real functions (26-XX) 4 Astronomy and astrophysics (85-XX) 3 History and biography (01-XX) 3 Harmonic analysis on Euclidean spaces (42-XX) 3 Mechanics of particles and systems (70-XX) 2 Convex and discrete geometry (52-XX) 2 Computer science (68-XX) 1 Mathematical logic and foundations (03-XX) 1 Measure and integration (28-XX) 1 Difference and functional equations (39-XX) 1 Approximations and expansions (41-XX) 1 Integral transforms, operational calculus (44-XX) 1 Manifolds and cell complexes (57-XX) 1 Relativity and gravitational theory (83-XX) 1 Operations research, mathematical programming (90-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2022-05-24T00:13:14 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.51584392786026, "perplexity": 7012.547775516213}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662562106.58/warc/CC-MAIN-20220523224456-20220524014456-00509.warc.gz"}
|
https://www.usgs.gov/center-news/volcano-watch-mount-st-helens-back-news
|
# Volcano Watch — Mount St. Helens back in the news
Release Date:
As most readers probably know, Mount St. Helens has reawakened after 18 years of repose. Here are some of the many questions HVO has received in the past few days, and the corresponding answers.
What has happened so far?
Earthquake activity (seismicity) rose above normal levels on September 23 and continued to increase over a period of days. A part of the crater floor-between the lava dome formed in the 1980s and the south crater wall-has been uplifted to about the height of the dome. Small steam and ash emissions have occurred from two small vents on the margin of the uplifted area. As of this writing, earthquakes have decreased. Magma is probably very near the surface.
Ok, so what is likely to happen? Monitoring tells us when a dormant volcano is reawakening, and when an eruption is imminent. But volcanologists can't predict the exact times, types, or magnitudes of eruptions that will occur. So they tabulate the nature and magnitude of various types of past eruptions and use the information to calculate the probabilities of various outcomes.
The range of possibilities at St. Helens is broad. There's about an 80 percent chance that a magmatic eruption will occur. If a magmatic eruption occurs, there's a 10 percent chance that there would be non-explosive dome growth and a 10 percent chance that a powerful explosive eruption would occur like the one on May 18, 1980, after the lateral explosion. There's also a 20 percent chance that activity could stop without an eruption.
What happened last time?
On May 18, 1980, after about a month-and-a-half of bulging and increased seismicity, the north flank became over steepened and it collapsed, producing an enormous landslide.
As the north flank slid away, it depressurized the magma that had accumulated inside the volcano. Gases dissolved in the magma suddenly expanded, and the magma exploded producing a huge, ground-hugging blast of rock particles and hot gas that swept out to the north, devastating 600 square kilometers (150 square miles) of mountainous, densely forested terrain. Just 5 minutes after the landslide began, the devastation was complete.
Shortly after the blast, a vertical eruption began that lasted about 9 hours. Ash rose to as much as 24 kilometers (15 miles) above the volcano, carried to the east-northeast by wind. Thousands of square kilometers in Washington, Idaho, and Montana were blanketed with ash. Pumice and ash flows reached Spirit Lake, 7 kilometers (4.5 miles) to the northeast.
The eruption blew the insides out of what had been a beautiful snow-capped volcanic cone, producing a crater more than a mile wide. Fifty-seven people were killed including David Johnston, a USGS scientist who was measuring the bulge rate from the first ridge north of the volcano about 9 kilometers (5.5 miles) away.
Smaller vertical eruptions occurred later in 1980 and eventually gave way to dome-building eruptions. The last of these occurred in October 1986.
Is there going to be another devastating blast?
A large lateral explosion like the one that occurred on May 18, 1980, is not likely because much of the pre-1980 volcano is gone precluding another flank collapse. Furthermore, deformation measurements show almost no change of the volcano's flanks but, rather on the crater floor. Explosive eruptions are likely to be directed upward instead of outward.
Some upward-directed explosions produce lethal ground-hugging clouds of ash and gas, when hot ash and pumice fountain back onto the volcano's flanks and flow down slope. Unlike lateral explosions, vertical explosions usually send out material in all directions. A given quantity of material erupted vertically typically does not go as far as the same quantity of material erupted laterally.
Stay tuned, we will most likely see a magmatic eruption at Mount St. Helens in coming days to months.
### Volcano Activity Update
Eruptive activity at Puu Oo continues weakly. The Banana flow is no longer active. Scattered breakouts are taking place within a wide expanse of the PKK flow east of the Banana flow, and one small tongue of lava has been moving down Pulama pali since September 22. The eruptive activity in Puu Oo's crater is weak, with sporadic minor spattering.
No earthquakes were reported felt on the island during the week ending October 6.
Mauna Loa is not erupting. The summit region continues to inflate slowly. Seismic activity continues at a slightly higher level than during the past several weeks. Only 47 earthquakes were recorded beneath the summit area during the past week. Nearly all of the earthquakes of this ongoing activity are of long-period type, have magnitudes less than 3, and are deep, 40 km (23 miles) or more.
| 2020-12-05T23:13:15 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.37417274713516235, "perplexity": 4720.520893814279}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141750841.83/warc/CC-MAIN-20201205211729-20201206001729-00324.warc.gz"}
|
https://www.usgs.gov/center-news/volcano-watch-lava-flow-forest-primary-succession
|
Volcano Watch — From lava flow to forest: Primary succession
Release Date:
One of the most striking aspects of a newly formed lava flow is its barren and sterile nature. The process of colonization of such flows by plants and animals is called primary succession, and it is also found on other newly formed surfaces such as glacial deposits, large landslides, and river deposits.
One of the most striking aspects of a newly formed lava flow is its barren and sterile nature. The process of colonization of such flows by plants and animals is called primary succession, and it is also found on other newly formed surfaces such as glacial deposits, large landslides, and river deposits. When new growth develops on previously vegetated areas that have been disturbed by floods, hurricanes, logging, bulldozing and the like, that process is called secondary succession.
Colonization of new flows begins almost immediately as certain native organisms specially adapted to the harsh conditions begin to arrive from adjoining areas. A wolf spider and cricket may be the first to take up residence, consuming other invertebrates that venture onto the forbidding new environment. The succession process relies heavily on adjacent ecosystems. A steady rain of organic material, seeds, and spores slowly accumulates in cracks and pockets along with tiny fragments of the new lava surface. Some pockets of this infant soil retain enough moisture to support scattered ohia seedlings and a few hardy ferns and shrubs. Over time, the progeny of these colonizers, and additional species from nearby forests, form an open cover of vegetation, gradually changing the conditions to those more favorable to other organisms. The accumulation of fallen leaves, bark, and dead roots is converted by soil organisms into a thin but rich organic soil. A forest can develop in wet regions in less than 150 years.
On Hawaiian lava flows, primary succession proceeds rapidly on wet windward slopes, but more slowly in dry areas. The influence of moisture can be seen on the Kona side, where the same flow can support a forest along the Belt Highway but be nearly barren near the dry coast. Except for the newer flows and disturbed areas, the windward surfaces of Kīlauea are heavily forested, but the leeward slope is barren or sparsely vegetated.
All the undisturbed flows on Kīlauea, Mauna Loa, and Hualālai volcanoes are young enough to be in some degree of primary succession, and the patterns and relative age of lava flows are reflected in the maturity of vegetation. Only a few of the newest flows on the dry upper slopes of dormant Mauna Kea are young enough to reflect primary succession. Extinct Kohala volcano is too old to find such flows, and vegetation differences reflect rainfall amounts and disturbance.
On wetter slopes of Hualālai and Mauna Loa, younger flows stand out against a more uniform, older background, as the surfaces are recovered by lava at rates of only 20 and 40 percent a century. Small and more active, Kīlauea renews about 90 percent of its surface in the same time period, and the resulting pattern is a patchwork of flows and vegetated remnants (kipuka). The many younger flows rely on the older kipuka to provide sources of plants and animals.
The native forest ecosystems have adapted to the overpowering nature of volcanic eruptions by being able to quickly recolonize from the many kipuka around new flows. However, the added losses due to forest clearing and alien invasion provide additional threats to which the native biota is not adapted. If too many of the native forest areas are cleared or taken over by introduced organisms, natural succession may not be able to provide a replacement native ecosystem on the younger flows. The continuing primary succession process may be already partially interrupted in lower Puna, where so much of the native forest has been cleared for development and where colonizers from nearby areas are mostly introduced organisms.
Volcano Activity Update
Lava continued to erupt from Puu O`o and flow through a network of tubes from the vent to the sea. No surface flows from breakouts of the tube system were observed on the coastal flats. Lava is entering the ocean near Kamokuna and forming a new bench. The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying frequent collapses of the new land. Especially vigorous explosions took place on Monday and Tuesday, sending spatter to heights of 100 m (300 feet). The steam clouds are highly acidic and laced with glass particles.
Two felt earthquakes were reported during the week ending on January 21. At 0610 a.m. on the 15th, a magitude 3.0 shake took place at a depth of 4 km (2.5 miles) beneath the upper east rift zone of Kīlauea and was feld in the summit area. Later in the same day, at 1256 pm.m, residents of the Waimea-Waikoloa area felt an earthquake of magnitude 3.5 located northwest of Mauna Kea summit at a depth of 31 km (19 miles).
| 2021-10-19T00:38:56 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3590751886367798, "perplexity": 4791.628998845768}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585215.14/warc/CC-MAIN-20211018221501-20211019011501-00211.warc.gz"}
|
https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_Introductory_Physics_-_Building_Models_to_Describe_Our_World_(Martin_Neary_Rinaldo_and_Woodman)/00%3A_Front_Matter/04%3A_Preface
|
$$\require{cancel}$$
# Preface
This textbook is shared under the CC-BY-SA 3.0 (Creative Commons) license. You are free to copy and redistribute the material in any medium or format, remix, transform, and build upon the material for any purpose, even commercially. You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
## Preface
This textbook is written to fill several needs that we believe were not already met by the many existing introductory physics textbooks. First, we wanted to ensure that the textbook is free to use for students and professors. Second, we wanted to design a textbook that is mindful of the new pedagogies being used in introductory physics, by writing it in a way that is adapted to a flipped-classroom approach where students complete readings, think about the readings, and then discuss the material in class. Third, we wanted to create a textbook that also addresses the experimental aspect of physics, by proposing experiments to be conducted at home or in the lab, as well as providing guidelines for designing experiments and reporting on experimental results. Finally, we wanted to create a textbook that is a sort of “living document”, that professors can edit and re-mix for their own needs, and to which students can contribute material as well. The textbook is hosted on GitHub, which allows anyone to make suggestions, point out issues and mistakes, and contribute material.
This textbook is meant to be paired with the accompanying “Question Library”, which contains many practice problems, many of which were contributed by students.
This textbook would not have been possible without the support of Queen’s University and the Department of Physics, Engineering Physics & Astronomy at Queen’s University, as well as the many helpful discussions with the students, technicians and professors at Queen’s University.
### Hello from the authors
Ryan Martin I am a professor of physics at Queen’s University. My main research is in the field of particle astrophysics, particularly in studying the properties of neutrinos. I grew up in Switzerland, obtained my Bachelor’s, Master’s and Ph.D. at Queen’s University. I was then a postdoctoral fellow at Lawrence Berkeley National Laboratory, a faculty at the University of South Dakota, before returning to Queen’s. I am particularly passionate about education, and I am always seeking opportunities to involve students in helping to make education more accessible. I also like to cook and to play volleyball.
Emma Neary I am currently a second year physics major and QuARMS (Queen’s University Accelerated Route to Medical School) student, as well as a native of St. John’s, Newfoundland. Uniting the perspectives of students and professors in an accessible way is important to me. I strongly believe in the importance of building physical models; whether it be in physics, medicine, sciences or the arts. It has been my goal to infuse the textbook with the theme of modelling in a creative and engaging way. Aside from doing physics, I enjoy hiking, dancing, reading and doing research in gastroenterology and neuropsychiatry.
Joshua Rinaldo I am a third year physics major and concurrent education student. I was first introduced to the flipped classroom approach in Ryan Martin’s first year physics class, and have found that the experience shaped the way I approach education. I intend on continuing to make use of the flipped classroom approach as I move forward in my career. Being able to co-author this textbook has been an amazing opportunity for me to grow as an educator, and I look forward to applying the skills I learned while working on the textbook. Outside of physics, I enjoy making jewelry and practicing mixed martial arts.
Olivia Woodman I am a currently a third year undergraduate student at Queen’s Univeristy, majoring in physics. The flipped classroom approach has been beneficial to my own learning, and I think that we have created a textbook that really complements this learning style. Throughout this book, I have shared my thoughts on various topics in physics, as well as some useful tips and tricks. I hope that students enjoy using this book and continue to contribute to it in the future. Working on this textbook has also allowed me to combine my love of physics with my love of doodling, so I hope you enjoy the drawings!
### How to use this textbook
This textbook is designed to be used in a flipped-classroom approach, where students complete readings at home, and the material is then discussed in class. The material is thus presented fairly succinctly, and contains Checkpoint Questions throughout that are meant to be answered as the students complete the reading. We suggest including these Checkpoint Questions as part of a quiz in a reading assignment (marked based on completion, not correctness), and then using these questions as a starting point for discussions in class.
For topics that are particularly difficult, we have included Thought Boxes written by students that try to present the material in a different light. We are always happy if students (or professors) wish to contribute additional thought boxes.
Chapters start with a set of Learning outcomes and an Opening question to help students have a sense of the chapter contents. The chapters have Examples throughout, as well as additional practice problems at the end. The Question Library should be consulted for additional practice problems. At the end of the chapter, a Summary presents the key points from the chapter. We suggest that students carefully read the summaries to make sure that they understand the contents of the chapter (and potentially identify, before reading the chapter, if the content is review to them). At the end of the chapters, we also present a section to Think about the material. This includes questions that can be assigned in reading assignments to research applications of the material or historical context. The thinking about the material section also includes experiments that can be done at home (as part of the reading assignment) or in the lab.
Appendices cover the main background in mathematics (Calculus and Vectors), as well as present an introduction to programming in python, which we feel is a useful skill to have in science. There is also an Appendix that is intended to guide work in the lab, by providing examples of how to write experimental proposals and reports, as well as guidelines for reviewing proposals and reports. We believe that introductory laboratories should not be be “recipe-based”, but rather that students should take an approach similar to that of a researcher in designing (proposing) an experiment, conducting it, and reviewing the proposals and results of their peers.
### Credits
This textbook, and especially the many questions in the Question Library would not have been possible without the many contributions from students, teaching assistants and other professors. Below is a list of the students that have contributed material that have made this textbook and the Question Library possible.
Alex Hughes
Alexis Brossard
Allyson Smith
Amy Van Nest
Camren Oakes
Ceaira Hiemstra
Damara Gagnier
Daniel Barake
Daniel Tazbaz
David Cutler
Emily Darling
Emily Mendelson
Emily Wener
Emma Lanciault
Erin Parson
Genevieve Fawcett
Gregory Love
Haoyuan Wang
Ian McClean
Jack Fitzgerald
James Godfrey
Jenna Vanker
Jesse Fu
Jesse Simmons
Jessica Grennan
Joanna Fu
Jonathan Abott
Kate Fenwick
Lily Dodd
Marie Vidal
Matt Routliffe
Maya Gibb
Natalie Dubas
Nathan Wilson
Neil Rajan
Nicholas Everton
Nick Brown
Nicole Gaul
Noah Rowe
Olivia Bouaban
Patrick Singal
Qiqi Zhang
Quentin Sanders
Robin Joshi
Ryan Underwood
Sam Connolly
Sara Stephens
Sarmund Mahmood
Shaundra Buelow
Shona Birkett
Stephanie Ciccone
Talia Castillo
Tamy Puniani
Thomas Faour
Troy Allen
Tashifa Imtiaz
Wei Zhuolin
Yannick Bisson
Yumian Chen
Zifeng Chen
Zoe Macmillan
| 2022-01-20T19:36:24 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.21044577658176422, "perplexity": 1322.537806730755}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320302622.39/warc/CC-MAIN-20220120190514-20220120220514-00231.warc.gz"}
|
http://xmm.esac.esa.int/sas/current/doc/attbin/node5.html
|
XMM-Newton Science Analysis System
attbin (attcalc2-1.3.3) [xmmsas_20130501_1901-13.0.0]
## Limits on attitude wander
The limits on attitude wander are defined via the parameter maxdelta, which is in arcseconds. The RA limit is set to
(1)
where is the average declination value (the exact meaning of `average' in this context is discussed in section 3.3 below). The declination limit is just set to maxdelta, and the position angle (apos) limit is set to
where is the nominal radius of the field of view of the XMM EPIC cameras.
XMM-Newton SOC/SSC -- 2013-05-02
| 2013-05-21T13:57:37 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9491387009620667, "perplexity": 5047.964367928413}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700074077/warc/CC-MAIN-20130516102754-00018-ip-10-60-113-184.ec2.internal.warc.gz"}
|
https://witcher.fandom.com/wiki/Character_attributes
|
## FANDOM
10,947 Pages
"Do you really wish to know?"
Spoilers from the books and/or adaptations to follow!
The Character attributes panel provides information on Geralt's current state within The Witcher 2: Assassins of Kings, and is accessed by choosing the Attributes menu from the Character Skills screen.
The information given includes Geralt's level, current stats, knowledge, and acquired abilities.
Level – Displays Geralt's current level (up to a maximum of 35), as well as the number of currently available talents and his progress in the current range of experience points to the next level.
## Character abilities
### Damage
How much damage Geralt can inflict with his currently equipped weapon, given as a range.
### Armor
The armor statistic describes how much protection Geralt's current armor and/or weapons provide. This statistic can also be boosted with the use of potions, trophies, and enhancements.
It's calculated as follows:
$IncomingDamage - Armor = ReceivedDamage$
So if a nekker hits at 35 and Geralt's current armor is 12, then it'd be:
35 - 12 = 23 damage to Geralt
### Vitality
Geralt's maximum level of vitality, with additional information about vitality regeneration during combat and outside of it. Geralt gains 5 vitality with each level.
### Vigor
Geralt's maximum level of vigor, with additional information about vigor regeneration during combat and outside of it, as well as with raised toxicity. The maximum level of Vigor is 9, with all the related skills suitably upgraded, and wearing the Armor of Ysgith, having used a Maribor Forest potion, and wielding the Forgotten Vran Sword together.[1]
### Resistance
List of active resistances and level of damage reduction.
### Critical effects
List of active critical effects.
### Bonus
List of active bonuses.
## Knowledge
Geralt's current knowledge about various monsters. The entries here are obtained via defeating a certain number of monsters or via reading a book on the monster.
## Abilities
Geralt can acquire certain permanent bonuses and other advantages by performing specific actions in specific locations or circumstances and interacting with various NPCs in specific ways.
• Axii Sign Hex, Intimidate, and Persuasion all have three levels; all other Abilities have only one.
• It isn't possible to acquire all of these abilities in a single play-through – mostly due to the branching paths in Chapter I, but also because four of them were coded for but never actually incorporated into the game.
• No ability carries over to any subsequent play-through, nor to The Witcher 3: Wild Hunt.
These abilities and how to acquire them are listed below:
Ability Effect Source Chapter
Anatomy lesson Damage against humans: +10%. Examine the body in the catacombs during With Flickering Heart quest in Chapter II (Iorveth's path). 2 (Iorveth)
Arcane Knowledge Intensity of all Signs: +0.5. Earned by completing The Gargoyle Contract in Chapter III. 3
Assassin Damage dealt by attacking from behind: +25% Find the dead Altaïr (from Assassin's Creed) look-alike next to some hay in the courtyard near the ballista during the Prologue. 0
Axii sign hex Allows the use of the Axii sign during conversations to obtain information or other benefits. Use the Axii sign option during specific conversations You can earn this Ability at any time in the game.
Batter Chance of instant kill with a redirected arrow: 20%. Requires ability to redirect arrows toward the shooter. Earned by redirecting approximately 10 arrows back at NPCs. 1
Battle seasoned Vigor regeneration when fighting +5% Not in the game, nor mentioned in the guide. It was supposed to be obtained after finishing the defense of Vergen in chapter II (Iorveth) or by winning all the fights during Ave Henselt! (Roche), but is unobtainable due to buggy scripts. Not in game
Birdman Damage against harpies: +10%. Complete The Harpy Contract quest during Chapter II (Iorveth's path). 2 (Iorveth)
Child of the night Vitality regeneration at night: +2. Sneak through the camp undetected during the Where is Triss Merigold? quest (Iorveth's path) near the end of Chapter II. 2 (Iorveth)
Conjuror Signs damage: +3. Automatically given for using the Axii Sign Hex during a conversation. You can earn this Ability at any time in the game.
Cover Damage reduction: +10%. Stay under Triss' protective umbrella without exiting during the beginning of Chapter I, or sneak up on the first two guards in Loredo's compound while looking for the Kayran trap, and knock them out. 1
David Damage dealt to opponents much bigger than Geralt: +10% Kill the golem in the kingslayer's hideout in Chapter II (Roche's path). 2 (Roche)
Executioner +1% to Instant Kill Chance Kill Aryan La Valette, Adam Pangratt and let Roche kill Henselt at the end of Chapter II. (Technically, Stennis can be substituted for Henselt in Iorveth's path, but a substitute for Pangratt is not known, so until further notice this ablility can only be won on Roche's path.) 0 (Roche)
Exorcist Damage against all spectres and wraiths: +10%. Remove the curse from the king in Chapter II (Roche's path). 2 (Roche)
Experienced +10% Bonus to Experience Earned Destroy 10 training dummies. 0 [and 1]
Haggling -20% to price of items in shops. Convince the merchant to double the fee by using the Axii sign during The Kayran: A Matter of Price quest in Chapter I. You get the ability after defeating the kayran and picking up payment from the merchant. 1
Half-Pirouette Resistance to all critical effects +10% Defeat Letho during the main story quest in Chapter I. To get the ability, you need to fight him until the cutscene kicks in, in which Geralt knocks the sword out of his hands. [This ability may not appear afterwards due to a buggy script.] 1
Healthy diet Regeneration of vitality when not fighting +20% Not in the game, nor mentioned in the guide. It was supposed to be obtained after beating the Mighty Numa, but is unobtainable due to buggy scripts. Not in game
Intimidate Allows the use of intimidation during conversations in order to obtain information or other benefits. Use the intimidate option during specific conversations like Geralt's interactions. You can earn this Ability at any time in the game.
Invincible Vitality +20 Not in the game, nor mentioned in the guide. It was supposed to be obtained after winning all the fistfights in chapter II (both paths), but is unobtainable due to buggy scripts. Not in game
Parry Chance of automatic riposte after blocking a blow: 10%. Requires the Riposte ability from the Swordsmanship tree. Earned by using Riposte a certain number of times. (Approximately 30-50 times, both silver and steel count towards the threshold) 1
Persuasion Allows the use of persuasion during conversations in order to obtain information or other benefits. Use the persuasion option during specific conversations. You can earn this Ability at any time in the game.
Precision Chance of all critical effects +5%. Not in the game, nor mentioned in the guide. Not in game
Pyromaniac Critical effect chance: incineration +20%. (It adds 20% of your actual incineration percentage, i.e. if you are wielding a sword with 2 fire runes which give you a 20% chance of incineration, with this ability you will make that 24% in total) Receive a certain amount of damage by being set on fire. Set Geralt ablaze by walking into a campfire and repeat approximately 5 times. You can earn this Ability at any time in the game.
Resistance to Magic Damage reduction in case of magical attacks: +20% (It adds 20% of your actual magic resistance, i.e. if you are wearing a set of armor that give you a 15% reduction of damage from magic, with this ability you will receive 18% in total) Reject Triss in the Elven Bath and cast Aard to open the way out during The Rose of Remembrance in Chapter I. 1
Sapper Chance of avoiding damage dealt by traps and bombs 50% Interrupt Geralt (by interacting with another object, using his medallion, or possibly using other methods) five times while he is in the process of disarming a trap.[3] 0 [and 1]
Strong Back Geralt can carry more items. Total Capacity: +50. Spare Aryan La Valette and help him escape the La Valette's dungeon during the Prologue. It will be awarded upon exiting the dungeon.[4] 0
Strong Stomach Resistance to critical effect: poisoning: +10%. Drink Mongoose potion during Chapter I. 1
Swordsman Damage caused during sword fights: +4. Awarded after defending King Henselt from the two assassins in Chapter II (Roche's path). 2 (Roche)
Summer's Crown Quen Sign: +10% chance to Incinerate enemies who strike while Quen is in effect. Awarded when visiting a shrine in Chapter I in the swamp outside Lobinden. (after patch 3.3) 1 (PC Only)
Thrower Damage dealt by throwing knives: +5. Defeat Ves in a knife throwing contest during the party at the Blue Stripes hangout in Chapter I. 1
Toxic Blood Opponents that damage Geralt may be poisoned if Geralt is using potions. Chance of poisoning 30%. Poison Geralt using several Devil's Puffball bombs.
You can earn this Ability at any time in the game.
Winter's Shroud Changes Aard Sign into the freezing Ice Aard, which adds a 20% chance of freezing opponents hit with the Sign. Awarded when visiting a shrine in Chapter III outside of Loc Muinne. (after patch 3.3) 3 (PC Only)
## Notes
1. Note, however, that the game will display only 8 bars representing the 9 Vigor levels, and the circle will be empty rather than showing a #9 character (nonagon). Still, you can cast Quen and see that now the circle will show the octagon square with all bars filled, meaning, you have 9 Vigor levels (one used for the Quen.)
2. One of the best ways is in Foltest's camp during the Prologue. There is a Circle of Power which grants +2 Vitality regeneration and near it is a camp fire. Use the Circle of Power, set yourself ablaze and regenerate very fast. Repeat.
3. This can be done in the Camp at game start. Set a trap, then interrupt with Medallion.
4. This can also be awarded by losing a fistfight (needs clarification). (See note on talk page)
Community content is available under CC-BY-SA unless otherwise noted.
| 2020-04-01T18:38:28 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4278280735015869, "perplexity": 8352.513097617395}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370505826.39/warc/CC-MAIN-20200401161832-20200401191832-00185.warc.gz"}
|
https://uvcdat.llnl.gov/Jupyter-notebooks/vcs/VCS_Basics/VCS_Basics.html
|
# Visualization Control System (VCS) Basic Tutorial¶
VCS allows scientists to produce highly customized plots. This tutorial provides an overview of VCS while other tutorials on the CDAT Tutorials page provide more specifics on additional VCS Principles, the VCS Template which controls many aspects of a plot, Text Objects in VCS and another example of using VCS to plot data from start to finish in the VCS Example tutorial. We recommend you also look at the CDMS 101 notebook.
The most direct way to work with this Jupyter Notebook is to download the notebook by right-clicking on the link below and chosing "Download Linked File As..." or "Save Link as...", activating a CDAT + Jupyter compatible environment, and running the notebook on its own or within a JupyterLab interface. For more details, see the Getting Started section below.
If you are unfamiliar with Jupyter Notebooks, they are files with an .ipynb extension that are made up of cells that can include executable code or regular text to explain what the code is doing. From Jupyter.org "The Jupyter Notebook is an open-source web application that allows you to create and share documents that contain live code, equations, visualizations and narrative text." Users can step through each cell in the notebook by putting their cursor in the cell they wish to run and either clicking on the "Run" button at the top of the page or pressing enter on the keyboard while holding down shift at the same time (shift-enter).
To download this Jupyter Notebook, right click on the link and choose "Download Linked File As..." or "Save Link as...". Remember where you save the downloaded file which should have an .ipynb extension. (You'll need to launch the Jupyter notebook or JupyterLab from the location where you store the notebook file.)
# Getting Started¶
This notebook uses Python 3.
If you only have Python 2 installed, the code should still work in Python 2, but if it doesn't, isn't this a good time to join the Python 3 crowd? The instructions below make it relatively painless to install a Python 3 environment.
For the code in this notebook to work, you need to install a CDAT compatible environment. See the next cell in the notebook for details on how to create an appropriate environment and activate it. If you see three grey dots, that cell has been hidden. Just click on the dots to see the contents of the cell. (To hide the cell in JupyterLab, click on the vertical blue bar to the left of the cell.)
## Conda Installation¶
We recommend using conda to install and manage environments. Conda itself can be installed either via Anaconda (the everything-but-the-kitchen-sink version) or Miniconda (the minimalist version).
I prefer Miniconda since it takes up less room on my computer and I don't mind installing the various packages I need when I need them. Miniconda (or Anaconda) will install Python on your computer. If you already have Python installed on your computer, see this helpful page. The choice of whether to install the Python 2.x or Python 3.x version of Miniconda will affect only your root environment. You can create both Python 2.x and Python 3.x environments with either version of Miniconda installed (and many environments can exist on your computer at the same time).
When installing Miniconda or Anaconda, let the installer add the conda installation of Python to your PATH environment variable. On a Mac or Linux machine, if asked "Do you wish the installer to initialize Anaconda3 by running conda init?" or something similar, we recommend saying "yes". For more details see this page.
## Create a CDAT Compatible Environment¶
Once you have a version of Miniconda (or Anaconda) installed, create a CDAT or Jupyter-VCDAT environment.
### For CDAT¶
1. Type the following code at a command line prompt. Note, since all output of code in this notebook will be displayed within the notebook, we do not need a separate display window so we can use the mesalib (or headless display) version of the latest version of the cdatX.x environment, which is currently cdat8.1.
conda create -n cdat81-mesa -c cdat/label/v81 -c conda-forge python=3.6 cdat mesalib
2. Once the cdat81-mesa environment is installed, activate it by typing:
conda activate cdat81-mesa
3. Install JupyterLab within your cdat81-mesa environment so you can run Jupyter notebooks:
conda install -c conda-forge jupyterlab
For additional details on creating a CDAT environment, see the following CDAT installation page.
### For VCDAT and the jupyter-vcdat environment¶
1. Follow these instructions for installing VCDAT 2.0 on your personal computer.
2. Once the jupyter-vcdat environment (and VCDAT) have been installed, activate the environment with:
conda activate jupyter-vcdat
### If "conda activate" doesn't work¶
Try:
source activate name_of_environment
## Start JupyterLab¶
Once you have a cdatXx-mesa or jupyter-vcdat environment activated, navigate to the parent folder that contains this notebook, then type:
jupyter-lab
Note: you must launch JupyterLab from the highest level folder you want to be able to access. Jupyter can see folders below the directory from which it was launched, but it cannot see directories above its launch directory.
If you do not want to use the enhanced JupyterLab interface, you can run:
jupyter-notebook
to load only the notebook without the JupyterLab interface.
Once JupyterLab (or Jupyter Notebook) has started, you may be asked to pick a Kernel. Choose the generic Python 3 environment or cdatXx-mesa or jupyter-vcdat. If you chose the generic Python 3 environment that means Jupyter will use whichever Python environment started the JupyterLab (or Jupyter Notebook) session. Hence it is best to start the JupyterLab session from an environment that contains CDAT.
As a side note, VCDAT and VCS are two different CDAT modules though they have similar acronyms. VCDAT 2.0 helps you visualize, manipulate data, and test out code within the JupyterLab interface. VCS stands for Visualization Control System which allows you to create customized plots and animations.
First let's download some sample data, specifically the three NetCDF files: ta_ncep_87-6-88-4.nc, clt.nc, and sampleCurveGrid4.nc, which will be stored in the same directory as this notebook.
In [1]:
from __future__ import print_function
import requests
import os
for filename in ['ta_ncep_87-6-88-4.nc', 'clt.nc', 'sampleCurveGrid4.nc']:
if not os.path.exists(filename):
r = requests.get("https://cdat.llnl.gov/cdat/sample_data/{}".format(filename), stream=True)
with open(filename,"wb") as f:
for chunk in r.iter_content(chunk_size=1024):
if chunk:
f.write(chunk) # write this chunk to a local version of the file
# Opening Data Files ¶
First we will open one of our demo files, which is done via the cdms2 module.
In the output below the code cell below, if you see a message that says "Allow anonymous logging usage to help improve CDAT(you can also set the environment variable CDAT_ANONYMOUS_LOG to yes or no)? [yes]/no:" either press enter (for yes) or type yes or no. If you do not respond with a return or yes or no, you will not be able to proceed.
In [2]:
import cdms2
f = cdms2.open("ta_ncep_87-6-88-4.nc")
# Querying File ¶
Next we will query the file to learn which variables are available.
In [3]:
f.variables.keys()
Out[3]:
dict_keys(['bounds_time', 'bounds_latitude', 'bounds_longitude', 'ta'])
We can obtain information on a specific variable using the info method. In the next line of code we look at the ta variable which is the Air Temperature in degrees Kelvin (K). The file contains:
• 11 months of Air Temperature data (the T axis),
• 17 different atmospheric pressure levels (the Z axis),
• 73 latitude bands (spanning from 90 to -90) (Y axis) and
• 144 longitude bands (spanning from 0 to 360) (X axis).
The latitude axis is Y and the longitude axis is X. (If this seems backwards, think of the values of latitude increasing or decreasing along the Y axis though the actual lines of latitude - or parallels - follow the X axis).
As you'll see in the output, the shape of the data is (11, 17, 73, 144). Each axis is also known as a dimension.
In [4]:
f["ta"].info()
*** Description of Slab ta ***
id: ta
shape: (11, 17, 73, 144)
filename: /Users/davis278/repos/Jupyter-notebooks/vcs/VCS_Basics/ta_ncep_87-6-88-4.nc
missing_value: [1.e+20]
grid_name: grid_73x144
grid_type: None
time_statistic:
long_name:
units:
title: Air Temperature [K]
Grid has Python id 0x11e9fd320.
Gridtype: generic
Grid shape: (73, 144)
Order: yx
** Dimension 1 **
id: time
Designated a time axis.
units: months since 1949-1-1 0:0
Length: 11
First: 461.0
Last: 471.0
Other axis attributes:
calendar: proleptic_gregorian
axis: T
Python id: 0x11e9fd2e8
** Dimension 2 **
id: level
Designated a level axis.
units: lev
Length: 17
First: 1000.0
Last: 10.0
Other axis attributes:
axis: Z
Python id: 0x11e9fd278
** Dimension 3 **
id: latitude
Designated a latitude axis.
units: degrees_north
Length: 73
First: -90.0
Last: 90.0
Other axis attributes:
axis: Y
Python id: 0x11e9fd240
** Dimension 4 **
id: longitude
Designated a longitude axis.
units: degrees_east
Length: 144
First: 0.0
Last: 357.5
Other axis attributes:
axis: X
modulo: [360.]
topology: circular
Python id: 0x11e9fd2b0
*** End of description for ta ***
In general, with the latitude dimension having a length of 73 (meaning there are 73 temperature values from -90 to 90 degrees) and the longitude dimension having a length of 144 (or 144 temperature values from 0 to 360 degrees), a single temperature value spans a 2.5 x 2.5 degree portion of the globe. The exception is in the latitude dimension which would normally have a length of 72 if all sections of the grid were 2.5 degrees. Instead, it has a length of 73 because the first and last grid elements (at -90 and 90 degrees) are each 1.25 degrees tall not 2.5. You can see this by displaying the latitude slices in the data using the getBounds() method.
In [5]:
f["ta"].getLatitude().getBounds()
Out[5]:
array([[-90. , -88.75],
[-88.75, -86.25],
[-86.25, -83.75],
[-83.75, -81.25],
[-81.25, -78.75],
[-78.75, -76.25],
[-76.25, -73.75],
[-73.75, -71.25],
[-71.25, -68.75],
[-68.75, -66.25],
[-66.25, -63.75],
[-63.75, -61.25],
[-61.25, -58.75],
[-58.75, -56.25],
[-56.25, -53.75],
[-53.75, -51.25],
[-51.25, -48.75],
[-48.75, -46.25],
[-46.25, -43.75],
[-43.75, -41.25],
[-41.25, -38.75],
[-38.75, -36.25],
[-36.25, -33.75],
[-33.75, -31.25],
[-31.25, -28.75],
[-28.75, -26.25],
[-26.25, -23.75],
[-23.75, -21.25],
[-21.25, -18.75],
[-18.75, -16.25],
[-16.25, -13.75],
[-13.75, -11.25],
[-11.25, -8.75],
[ -8.75, -6.25],
[ -6.25, -3.75],
[ -3.75, -1.25],
[ -1.25, 1.25],
[ 1.25, 3.75],
[ 3.75, 6.25],
[ 6.25, 8.75],
[ 8.75, 11.25],
[ 11.25, 13.75],
[ 13.75, 16.25],
[ 16.25, 18.75],
[ 18.75, 21.25],
[ 21.25, 23.75],
[ 23.75, 26.25],
[ 26.25, 28.75],
[ 28.75, 31.25],
[ 31.25, 33.75],
[ 33.75, 36.25],
[ 36.25, 38.75],
[ 38.75, 41.25],
[ 41.25, 43.75],
[ 43.75, 46.25],
[ 46.25, 48.75],
[ 48.75, 51.25],
[ 51.25, 53.75],
[ 53.75, 56.25],
[ 56.25, 58.75],
[ 58.75, 61.25],
[ 61.25, 63.75],
[ 63.75, 66.25],
[ 66.25, 68.75],
[ 68.75, 71.25],
[ 71.25, 73.75],
[ 73.75, 76.25],
[ 76.25, 78.75],
[ 78.75, 81.25],
[ 81.25, 83.75],
[ 83.75, 86.25],
[ 86.25, 88.75],
[ 88.75, 90. ]])
# First Plot ¶
Now, let's visualize the ta variable. For this we will need the vcs module. We will also need a vcs canvas upon which to plot the data.
In [6]:
import vcs
canvas = vcs.init()
canvas.plot(f["ta"]) # This plots the first time interval (1987/6/1) and the first atmospheric level (1000).
Out[6]:
# Subsetting Data¶
In the above plot we used all the variable dimensions (time, level, latitude and longitude) and the resulting plot is a boxfill plot. (If the data has at least two dimensions for the variable being plotted, the default plot type is boxfill.)
You can load and use a subset of the dimensions, however. Notice how we can use either the actual dimension value (e.g. -90 for longitude) or indices (via slice). For this dataset, the longitude values range from 0 to 360, so specifying a -90 value for longintude means 360-90 = 270.
In [7]:
data = f["ta"](longitude=-90, latitude=40, level=500, time=slice(0,1))
print(data)
[[[[263.4303]]]]
In the previous example, we fixed all dimensions and the command returned a single value. Let's subset longitude to a range rather than a single value and plot it.
The "squeeze" parameter in the first line below prevents dimensions of length 1 (e.g. latitude, level, and time) from being plotted.
In [8]:
data = f["ta"](longitude=(0,180), latitude=40, level=500, time=slice(0,1), squeeze=1)
canvas.clear()
canvas.plot(data)
Out[8]:
# Using Isolines¶
If we want an isoline rather than the default boxfill, we will need to create the associated isoline graphic rendering object using vcs' createisoline method.
In [9]:
isoline = vcs.createisoline()
data = f("ta")
canvas.clear()
canvas.plot(data, isoline)
Out[9]:
# Cross Sections¶
Now, let's plot a cross section of the data.
In [10]:
canvas.clear()
data = f["ta"](longitude=-90, latitude=(-90,90), level=(1000,100), time=slice(0,1), squeeze=1)
canvas.plot(data, isoline)
Out[10]:
We can also colorize the isolines, if we want, and turn on labels.
In [11]:
levels = vcs.mkscale(*vcs.minmax(data))
colors = vcs.getcolors(levels)
isoline.levels = levels
isoline.linecolors = colors
isoline.label = True
isoline.textcolors= colors
canvas.clear()
canvas.plot(data, isoline)
Out[11]:
# Easy Plot Tweaks¶
We can also control the dimensions' "range" on the plot via the isoline graphic rendering object,
In [12]:
data = f["ta"](longitude=-90, time=slice(0,1), squeeze=1)
# The next two lines put the North Pole on the left of the plot
isoline.datawc_x1 = 90
isoline.datawc_x2 = -90
isoline.datawc_y1 = 3 # log10(1000)
isoline.datawc_y2 = 2.3 # log10(200)
Or tweak the axes' scale (turn the y axis of the plot (not the data) - the atmospheric pressure levels - into a base 10 logarithmic scale),
In [13]:
isoline.yaxisconvert = "log10"
Or change the default labels.
In [14]:
isoline.yticlabels1 = {1000:"1000", 800:"800", 500: "500", 20:"20"}
canvas.clear()
canvas.plot(data, isoline)
Out[14]:
# Overlays¶
Now let's overlay another variable from a different NetCDF file: the u component of the wind from the clt.nc file. Since u has different values than the previous ta variable, we will create a separate isoline graphic rendering object, iso2.
In [15]:
f2 = cdms2.open("clt.nc")
u = f2("u", longitude=-90., time=slice(0,1), squeeze=1) # First time slice
iso2 = vcs.createisoline(source=isoline) # Essentially makes a copy
levels = vcs.mkscale(*vcs.minmax(u))
iso2.levels = levels
colors = ["blue",] # Blue lines
iso2.linecolors = colors
iso2.textcolors = colors
canvas.clear()
canvas.plot(data, isoline)
canvas.plot(u, iso2)
Out[15]:
| 2019-08-18T13:40:31 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2606543004512787, "perplexity": 7474.0516182311585}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027313889.29/warc/CC-MAIN-20190818124516-20190818150516-00082.warc.gz"}
|
https://sfyctraining.hants.gov.uk/course/info.php?id=123
|
### Environment Rating Scales
Please complete this section first, before proceeded on to your specific area.
| 2020-09-23T23:00:53 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8016892671585083, "perplexity": 8636.050137845226}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400212959.12/warc/CC-MAIN-20200923211300-20200924001300-00475.warc.gz"}
|
https://par.nsf.gov/biblio/10303335-deep-multi-task-mining-calabiyau-four-folds
|
Abstract
We continue earlier efforts in computing the dimensions of tangent space cohomologies of Calabi–Yau manifolds using deep learning. In this paper, we consider the dataset of all Calabi–Yau four-folds constructed as complete intersections in products of projective spaces. Employing neural networks inspired by state-of-the-art computer vision architectures, we improve earlier benchmarks and demonstrate that all four non-trivial Hodge numbers can be learned at the same time using a multi-task architecture. With 30% (80%) training ratio, we reach an accuracy of 100% for$h(1,1)$and 97% for$h(2,1)$(100% for both), 81% (96%) for$h(3,1)$, and 49% (83%) for$h(2,2)$. Assuming that the Euler number is known, as it is easy to compute, and taking into account the linear constraint arising from index computations, we get 100% total accuracy.
Authors:
; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10303335
Journal Name:
Machine Learning: Science and Technology
Volume:
3
Issue:
1
Page Range or eLocation-ID:
Article No. 015006
ISSN:
2632-2153
Publisher:
IOP Publishing
National Science Foundation
##### More Like this
1. Abstract
We use ALMA observations of CO(2–1) in 13 massive (M*≳ 1011M) poststarburst galaxies atz∼ 0.6 to constrain the molecular gas content in galaxies shortly after they quench their major star-forming episode. The poststarburst galaxies in this study are selected from the Sloan Digital Sky Survey spectroscopic samples (Data Release 14) based on their spectral shapes, as part of the Studying QUenching at Intermediate-z Galaxies: Gas, angu$L→ar$momentum, and Evolution ($SQuIGGL⃗E$) program. Early results showed that two poststarburst galaxies host large H2reservoirs despite their low inferred star formation rates (SFRs). Here we expand this analysis to a larger statistical sample of 13 galaxies. Six of the primary targets (45%) are detected, with$MH2≳109$M. Given their high stellar masses, this mass limit corresponds to an average gas fraction of$〈fH2≡MH2/M*〉∼7%$or ∼14% using lower stellar masses estimates derived from analytic, exponentially declining star formation histories. The gas fraction correlates with theDn4000 spectral index, suggesting that the cold gas reservoirs decrease with time since burst, as found in local K+A galaxies. Star formation histories derived from flexible stellar population synthesis modeling support thismore »
2. Abstract
Cosmic reionization was the last major phase transition of hydrogen from neutral to highly ionized in the intergalactic medium (IGM). Current observations show that the IGM is significantly neutral atz> 7 and largely ionized byz∼ 5.5. However, most methods to measure the IGM neutral fraction are highly model dependent and are limited to when the volume-averaged neutral fraction of the IGM is either relatively low ($x¯HI≲10−3$) or close to unity ($x¯HI∼1$). In particular, the neutral fraction evolution of the IGM at the critical redshift range ofz= 6–7 is poorly constrained. We present new constraints on$x¯HI$atz∼ 5.1–6.8 by analyzing deep optical spectra of 53 quasars at 5.73 <z< 7.09. We derive model-independent upper limits on the neutral hydrogen fraction based on the fraction of “dark” pixels identified in the Lyαand Lyβforests, without any assumptions on the IGM model or the intrinsic shape of the quasar continuum. They are the first model-independent constraints on the IGM neutral hydrogen fraction atz∼ 6.2–6.8 using quasar absorption measurements. Our results give upper limits of(1σ),$x¯HI(z=6.5)<0.87±0.03$(1σ), and$x¯HI(z=6.7)<0.94−0.09+0.06$(1σ). The dark pixel fractions atz> 6.1 are consistent with the redshift evolution of the neutral fraction of the IGM derived from Planck 2018.
3. Abstract
The best upper limit for the electron electric dipole moment was recently set by the ACME collaboration. This experiment measures an electron spin-precession in a cold beam of ThO molecules in their metastable$H(3Δ1)$state. Improvement in the statistical and systematic uncertainties is possible with more efficient use of molecules from the source and better magnetometry in the experiment, respectively. Here, we report measurements of several relevant properties of the long-lived$Q(3Δ2)$state of ThO, and show that this state is a very useful resource for both these purposes. TheQstate lifetime is long enough that its decay during the time of flight in the ACME beam experiment is negligible. The large electric dipole moment measured for theQstate, giving rise to a large linear Stark shift, is ideal for an electrostatic lens that increases the fraction of molecules detected downstream. The measured magnetic moment of theQstate is also large enough to be used as a sensitive co-magnetometer in ACME. Finally, we show that theQstate has a large transition dipole moment to the$C(1Π1)$state, which allows for efficient population transfer between the ground stateand theQstate via$X−C−Q$Stimulated Raman Adiabatic Passage (STIRAP). We demonstrate 90 % STIRAP transfer efficiency. In the course of these measurements, we also determine the magnetic moment ofCstate, the$X→C$transition dipole moment, and branching ratios of decays from theCstate.
4. Abstract
The genericity of Arnold diffusion in the analytic category is an open problem. In this paper, we study this problem in the followinga prioriunstable Hamiltonian system with a time-periodic perturbation$Hε(p,q,I,φ,t)=h(I)+∑i=1n±12pi2+Vi(qi)+εH1(p,q,I,φ,t),$where$(p,q)∈Rn×Tn$,$(I,φ)∈Rd×Td$withn,d⩾ 1,Viare Morse potentials, andɛis a small non-zero parameter. The unperturbed Hamiltonian is not necessarily convex, and the induced inner dynamics does not need to satisfy a twist condition. Using geometric methods we prove that Arnold diffusion occurs for generic analytic perturbationsH1. Indeed, the set of admissibleH1isCωdense andC3open (a fortiori,Cωopen). Our perturbative technique for the genericity is valid in theCktopology for allk∈ [3, ∞) ∪ {∞,ω}.
5. Abstract
We present a chemodynamical study of the Grus I ultra-faint dwarf galaxy (UFD) from medium-resolution (R∼ 11,000) Magellan/IMACS spectra of its individual member stars. We identify eight confirmed members of Grus I, based on their low metallicities and coherent radial velocities, and four candidate members for which only velocities are derived. In contrast to previous work, we find that Grus I has a very low mean metallicity of 〈[Fe/H]〉 = −2.62 ± 0.11 dex, making it one of the most metal-poor UFDs. Grus I has a systemic radial velocity of −143.5 ± 1.2 km s−1and a velocity dispersion of$σrv=2.5−0.8+1.3$km s−1, which results in a dynamical mass of$M1/2(rh)=8−4+12×105$Mand a mass-to-light ratio ofM/LV=$440−250+650$M/L. Under the assumption of dynamical equilibrium, our analysis confirms that Grus I is a dark-matter-dominated UFD (M/L> 80M/L). However, we do not resolve a metallicity dispersion (σ[Fe/H]< 0.44 dex). Our results indicate that Grus I is a fairly typical UFD with parameters that agree with mass–metallicity and metallicity-luminosity trends for faint galaxies. This agreement suggests that Grus I has not lost an especially significant amount of mass from tidal encounters with the Milky Way, in linemore »
| 2023-01-27T20:23:44 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 26, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6260637044906616, "perplexity": 2919.596515524035}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764495012.84/warc/CC-MAIN-20230127195946-20230127225946-00557.warc.gz"}
|
https://pos.sissa.it/334/306/
|
Volume 334 - The 36th Annual International Symposium on Lattice Field Theory (LATTICE2018) - Poster reception
Determination of the N$_f$=12 step scaling function using Möbius domain wall fermions
A. Hasenfratz*, C. Rebbi and O. Witzel
Full text: pdf
Published on: May 29, 2019
Abstract
We calculate the renormalized step scaling function for twelve fundamental flavors nonperturbatively by determining the gradient flow coupling on gauge field configurations generated with dynamical stout-smeared M\"obius domain wall fermions and Symanzik gauge action. Using Zeuthen, Symanzik, and Wilson flow we measure the energy density with three different operators. Our updated analysis is based on up to five volume pairs ranging from $L^4=8^4$ up to $32^4$. Predictions for the infinite volume extrapolated step scaling function based on different flows and operators are mutually consistent. Our new results confirm the previously observed significant discrepancy with staggered fermion simulations in a wide range of the renormalized coupling.
DOI: https://doi.org/10.22323/1.334.0306
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2023-02-04T08:37:29 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.22035974264144897, "perplexity": 2607.2533810198156}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500095.4/warc/CC-MAIN-20230204075436-20230204105436-00312.warc.gz"}
|
https://mfix.netl.doe.gov/doc/nodeworks/20.2.0/userguide/sma/doe.html
|
# Design of Experiments¶
The Design of Experiments is used to choose the sampling points to be used as input parameters for full model evaluation. It is important in this stage to consider the potential range of interest and ensure that the sampling space completely covers this range so that the resulting surrogate model is analyzed within its range of support.
## Variables¶
Variables are added in the first Variables tab by clicking on the symbol above the table. Variables can be removed from the table by highlighting them in the table and clicking on the symbol. Information about the variable properties are entered and edited in the entry spaces below the table. Some of the properties are type specific, discussed below. All entered variables are listed and summarized in the table.
Variable properties:
• variable: used to name and identify the variables.
• arg(s): defines the variable argument, i.e., the ineger index if the variable is an array or vector.
• units: specify variable units for plotting.
• type: Double Precision real variables.
• link used to specify the variable as a function of another variable. NOTE that the variable is no longer an independent variable, which can be important when sampling randomly. However, it can also be useful when dependent variables need to be set consistently with one independent random variable. The plot below shows a two variable array which must sum to one like the volume fraction of a two-phase mixture, for example.
• from: lower bound of parameter space of this variable dimension.
• to: upper bound of parameter space of this variable dimension.
• levels: defines the number of evenly spaced sampling points between from and to inclusively. NOTE that this is only used in the specific instance when the factorial design is specified on the Design tab and the Use variable specific levels option is checked.
• type: Integer integer valued variables have the same properties as Double Precision variables. NOTE that integers are also treated the same as reals during the calculation of the sampling points and then rounded. Care should be taken to avoid unwanted repeated samples.
• type: String text based variables can be added and removed with the + and - symbols, activated by checking the box and named by double clicking on the entry space to the right of the checkbox. NOTE that the functionality of String variables is not currently fully implemented. Specifically, downstream nodes can not handle string variables. Currently, it is recommended that users convert strings into integer or real variables.
• type: Logical variables only take integer values of 1 or 0 for True or False.
A design where two variables are linked.
## Design¶
The Design tab is where the samples are actually constructed. Generally speaking, there are four ways to construct a sampling scheme: ordered, sequentially (sub-random), pseudo-randomly and simply importing a design constructed previously or from a different code. Available Method’s include
Ordered designs:
Sequential designs
Random designs
Previously generated designs
• The Import button is used to load a design saved locally in csv, comma separated variable format
• Samples specifies the total number of samples drawn
• Repeat specifies how many samples are repeated a specified number of times–this can be useful when generating designs for actual experiments and for non-deterministic simulations
• Randomize sample order–this applies to the table as well as the order in which the samples are transferred to downstream nodes
• Build generates the samples, also used to re-generate the design if properties are adjusted
• Export exports the samples to a comma separated variable file
Some other method-specific properties:
• Randomize toggles between setting the seed of the pseudorandom number generator from the given seed or from the clock NOTE that randomize should be used with caution and the accepted design should be saved with Export as the design will be re-generated and changed when the sheet is run
• Levels a constant number number of sampling intervals to be used with all variables with the Factorial design
• Alternatively, users may check Use variable specific levels and the intervals for each variable are taken from the levels value entered previously in the Variables tab
• Face in the central composite design specifies circumscribed, inscribed or faced
• Alpha in the central composite design specifies orthogonal or rotatable
• Optimize in the latin hypercube design allows selection of an optimization technique to improve the space filling of the design. See Latin Hypercube for more.
• Iterations in the latin hypercube design allows for the specification of iterations used by the Optimize technique.
Example of designs with 30 samples.
## Plot¶
The samples are plotted in a 2D scatter plot. The variables can be set by selecting the Y Axis and X Axis variables from the dropdown list. The plot can be customized and saved using the buttons below the plot. By default, all variables are shown with included points in blue and excluded points in red. Excluded and/or included points can be alternatively turned off by right clicking on the plot and unchecking.
## Quality¶
The Quality tab analyzes the spatial quality of the design. The Minimum Distance, Maximum Distance and their Ratio (Max/Min) are reported and calculated using scipy.spatial.distance.pdist. Several Distance Metric options are available from the scipy library:
The L2-Discrepancy from Eq.5 of [Fang2001b] is also calculated for the design.
$WD^2(D) = -(4/3)^K + 1/N^2 \Sigma_{i,j=1}^{N} Pi_{k=1}^K [3/2 - |x_k^1 - x_k^2| * (1 - |x_k^1 - x_k^2|)]$
### References¶
Fang2001b
K.T. Fang and C.X. Ma, “Wrap-Around L2-Discrepancy of Random Sampling, Latin Hypercube, and Uniform Designs,” Journal of Complexity, vol. 17, pp. 608-624, 2001.
| 2020-10-22T15:48:45 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3579525947570801, "perplexity": 1293.5262686650606}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107879673.14/warc/CC-MAIN-20201022141106-20201022171106-00220.warc.gz"}
|
http://dlmf.nist.gov/10.67
|
# §10.67 Asymptotic Expansions for Large Argument
## §10.67(i) , and Derivatives
Define and as in §§10.17(i) and 10.17(ii). Then as with fixed,
The contributions of the terms in , , , and on the right-hand sides of (10.67.3), (10.67.4), (10.67.7), and (10.67.8) are exponentially small compared with the other terms, and hence can be neglected in the sense of Poincaré asymptotic expansions (§2.1(iii)). However, their inclusion improves numerical accuracy.
As
| 2013-05-22T23:08:07 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9166659116744995, "perplexity": 2380.0108835901256}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368702454815/warc/CC-MAIN-20130516110734-00017-ip-10-60-113-184.ec2.internal.warc.gz"}
|
http://www.bnl.gov/physics/NTG/seminars.php
|
# Seminars
1. MAY
26
Today
Nuclear Physics Seminar
"Probing Nucleon Structure Through Transversely Polarized Proton-proton Collisions at STAR"
Presented by Jim L. Drachenberg, Valparaiso University
11 am, Small Seminar Room, Bldg. 510
Tuesday, May 26, 2015, 11:00 am
Hosted by: Oleg Eyser
At leading twist, a complete picture of the one-dimensional momentum structure of the nucleon requires knowledge of three types of parton distribution functions (PDFs): the unpolarized PDFs; the helicity PDFs; and the transversity PDF, related to the transverse polarization of quarks within a transversely polarized nucleon. Current global extractions of transversity are limited by the kinematic reach of existing semi-inclusive deep-inelastic scattering (SIDIS) experiments. Beyond the open questions of one-dimensional nucleon structure, myriad opportunities abound in exploring the multi-dimensional structure of the nucleon. A step toward this goal is to investigate the nature of the transverse momentum dependence (TMD) of nucleon parton densities and their relation to nucleon spin polarization. The STAR experiment at RHIC proposes to investigate these and other spin-related phenomena through the interaction of high-energy collisions between spin-polarized protons. In preliminary results from data collected in 2011 at $\sqrt{s}=500$ GeV and in 2012 at $\sqrt{s}=200$ GeV, STAR has observed the first non-zero spin asymmetries due to the effects of transversity in proton-proton collisions. Studying these effects through both jet+hadron and di-hadron production channels and across a range of collision energy yields the potential not only to extend understanding of transversity beyond the current kinematic reach but also to address longstanding theoretical questions concerning the universality and evolution of transversity and polarized fragmentation functions. From the 2011 dataset STAR has also released the first preliminary measurements sensitive to the Sivers TMD PDF in weak-boson production. Weak boson production provides an ideal tool for isolating the unconstrained sea-quark Sivers PDF and may provide sensitivity to the expected modified universality of the Sivers PDF when compared to SIDIS. These exploratory measurements pave the way for future higher precision inv
2. JUN
2
Tuesday
Nuclear Physics Seminar
"Elliptic flow from anisotropic escape"
Presented by Denes Molnar, Purdue University
11 am, Small Seminar Room, Bldg. 510
Tuesday, June 2, 2015, 11:00 am
Hosted by: Jin Huang
While hydrodynamics is regarded as the dominant paradigm for describing heavy-ion collisions at RHIC and LHC energies, its applicability to nuclear reactions is not very well understood. Open question remain about the mechanism of rapid thermalization, initial conditions, treatment of decoupling (conversion of the fluid to particles), finite system effects, and quantum corrections in very small systems, for example. In a recent work (arXiv:1502.05572) we showed that in the AMPT transport model elliptic flow is generated quite differently from hydrodynamics, mainly through anisotropic escape from the collision zone. I will demonstrate that this is, in fact, a general feature of kinetic theory, originating in the modest opacities <Ncoll> \sim 4-5 in AMPT calculations. Implications of the escape effect will be discussed together with connections to other hydro related problems such as proper particle distributions (arXiv:1404.8750) and anisotropic flow from quantum mechanics (arXiv:1404.4119).
3. JUN
4
Thursday
RIKEN Lunch Seminar
"Non-relativistic particles in a thermal bath"
Presented by Antonio Vairo, Munich Technical University
12:30 pm, Building 510 Room 2-160
Thursday, June 4, 2015, 12:30 pm
Hosted by: Tomomi Ishikawa
4. JUN
5
Friday
Nuclear Theory/RIKEN Seminar
"Novel mechanisms of charmonium suppression/enhancement in pA and AA collisions"
Presented by Boris Kopeliovich, Universidad Tecnica Federico Santa Maria, Valparaiso
2 pm, Small Seminar Room, Bldg. 510
Friday, June 5, 2015, 2:00 pm
Hosted by: Soeren Schlichting
5. JUN
5
Friday
Nuclear Theory/RIKEN seminar
"Novel mechanisms of charmonium suppression/enhancement in pA and AA collisions"
Presented by Boris Kopeliovich, Universidad Tecnica Federico Santa Maria, Valparaiso
2 pm, Small Seminar Room, Bldg. 510
Friday, June 5, 2015, 2:00 pm
Hosted by: Soeren Schlichting
Charmonium production in pA collisions is known to be suppressed by shadowing and absorption. There are however nuclear effects, which enhance charmonium yield. They steeply rise with energy and seem to show up in LHC data for J/psi production in pA collisions. In the case of heavy ion collisions produced charmonia are additionally suppressed by final state interaction in the created dense medium. On the contrary to current evaluations of the melting effects caused by Debye screening, a charmonium produced with a large pT easily survives even at high temperatures. Another source of charmonium suppression, missed in previous calculations, color-exchange interactions with the medium, leads to suppression of a comparable magnitude. A quantitative comparison is performed.
6. JUN
10
Wednesday
HET/RIKEN seminar
"TBA"
Presented by Wolfgang Altmannshofer, Perimeter Institute
2 pm, Small Seminar Room, Bldg. 510
Wednesday, June 10, 2015, 2:00 pm
Hosted by: Chien-Yi Chen
7. JUN
25
Thursday
RIKEN Lunch Seminar
"TBA"
Presented by Jacobus Verbaarschot, Stony Brook University
12:30 pm, Building 510 Room 2-160
Thursday, June 25, 2015, 12:30 pm
Hosted by: Daniel Pitonyak
8. JUN
26
Friday
Nuclear Theory/RIKEN Seminar
"TBA"
Presented by Jacobus Verbaarschot, Stonybrook University
2 pm, Small Seminar Room, Bldg. 510
Friday, June 26, 2015, 2:00 pm
Hosted by: Soeren Schlichting
1. Nuclear Physics Seminar
"High-pt Hadron Production in Au+Au and d+Au Collisions at sqrt (s) = 200 GeV"
Presented by Sasha Milov, Stony Brook University
Tuesday, July 1, 2003, 11 am
Small Seminar Room, Bldg. 510
2. Nuclear Physics Seminar
"Production of Lambda (1520) at RHIC at sqrt (s) = 200 GeV"
Presented by Ludovic Gaudichet, Subatech, France
Tuesday, July 15, 2003, 11 am
Small Seminar Room, Bldg. 510
3. Nuclear Physics Seminar
"Induced Criticality of Non-Order Parameter Fields"
Presented by Agnes Mocsy, Niels Bohr Institute, Denmark
Tuesday, July 22, 2003, 11 am
Small Seminar Room, Bldg. 510
4. Nuclear Physics Seminar
"Strangeness Production in Au+Au Collisions at RHIC"
Presented by Ben Norman, Kent State University
Tuesday, July 29, 2003, 11 am
Small Seminar Room, Bldg. 510
5. Nuclear Physics & RIKEN Theory Seminar
"Hydrodynamic Afterburner for Color Glass Condensate"
Presented by Yasushi Nara, University of Arizona
Friday, August 8, 2003, 2 pm
Small Seminar Room, Bldg. 510
6. High-Energy Physics & RIKEN Theory Seminar
"Strong Interaction Effect on Muon g-2"
Presented by Masashi Hayakawa, RIKEN/BNL Research Center
Sunday, August 10, 2003, 1:30 pm
Small Seminar Room, Bldg. 510
7. High-Energy Physics & RIKEN Theory Seminar
"Elitzurs Theorem and the Sign Problem"
Presented by Kim Splittorff, Stony Brook University
Wednesday, August 13, 2003, 1:30 pm
Small Seminar Room, Bldg. 510
8. Instrumentation Division Seminar
"Development of Novel Silicon Stripixel Detectors for High energy and Nuclear Physics Experiments"
Presented by Zheng Li, Instrumentation Division
Wednesday, September 10, 2003, 2:30 pm
Large Seminar Room, Bldg. 535
9. Nuclear Physics Seminar
"Discovery of Penta Quarks"
Presented by Prof. Ken-chi Imai, Kyoto University, Japan
Tuesday, October 14, 2003, 11 am
Small Seminar Room, Bldg. 510
10. RIKEN BNL Research Center Workshop
"Collective Flow and QGP Properties"
Monday, November 17, 2003, 9 am
Large Seminar Room, Bldg. 510
| 2015-05-26T07:42:08 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7271295189857483, "perplexity": 14263.887158892274}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1432207928817.29/warc/CC-MAIN-20150521113208-00314-ip-10-180-206-219.ec2.internal.warc.gz"}
|
https://zbmath.org/authors/?q=ai%3Abrown.gavin.1
|
# zbMATH — the first resource for mathematics
## Brown, Gavin
Compute Distance To:
Author ID: brown.gavin.1 Published as: Brown, G.; Brown, Gavin External Links: MGP · Math-Net.Ru · Wikidata · dblp · MacTutor
Documents Indexed: 125 Publications since 1967
all top 5
#### Co-Authors
27 single-authored 39 Moran, William 12 Wang, Kunyang 10 Yin, Qinghe 9 Móricz, Ferenc 7 Dooley, Anthony Haynes 7 Koumandos, Stamatis 6 Hewitt, Edwin 6 Pearce, Charles Edward Miller 5 Dai, Feng 5 Feng, Dai 4 Wilson, David Charles 3 Pollington, Andrew Douglas 3 Williamson, John H. 1 Bailey, W. J. 1 Chandler, Graeme A. 1 Glicksberg, Irving Leonard 1 Graham, Colin D. 1 Karanikas, Costas 1 Keane, Michael S. 1 Lake, Jane 1 Michon, Guy Jean 1 Pečarić, Josip 1 Peyrière, Jacques 1 Pryce, John D. 1 Safar, Zoltan 1 Sanders, Jeff W. 1 Sheng, Sun Yong 1 Sloan, Ian Hugh 1 Sun, Yongsheng 1 Tijdeman, Robert
all top 5
#### Serials
11 Mathematical Proceedings of the Cambridge Philosophical Society 6 Journal of the London Mathematical Society. Second Series 6 Acta Mathematica Hungarica 6 Journal of the Australian Mathematical Society. Series A 5 Bulletin of the London Mathematical Society 4 Proceedings of the Edinburgh Mathematical Society. Series II 4 Proceedings of the London Mathematical Society. Third Series 4 Proceedings of the Royal Irish Academy. Section A, Mathematical and Physical Sciences 4 Proceedings of the Cambridge Philosophical Society 3 Studia Mathematica 3 Mathematische Annalen 3 Ergodic Theory and Dynamical Systems 3 The Journal of Fourier Analysis and Applications 2 Journal of Mathematical Analysis and Applications 2 Acta Scientiarum Mathematicarum 2 Journal of Functional Analysis 2 Monatshefte für Mathematik 2 Pacific Journal of Mathematics 2 Tohoku Mathematical Journal. Second Series 2 Advances in Mathematics 2 Mathematical Inequalities & Applications 2 Journal of the London Mathematical Society 1 Bulletin of the Australian Mathematical Society 1 Journal of Statistical Physics 1 Periodica Mathematica Hungarica 1 Acta Mathematica 1 Advances in Mathematics 1 Colloquium Mathematicum 1 Duke Mathematical Journal 1 Glasgow Mathematical Journal 1 Inventiones Mathematicae 1 Journal of Applied Probability 1 Journal of Number Theory 1 Mathematika 1 Osaka Journal of Mathematics 1 Proceedings of the American Mathematical Society 1 The Quarterly Journal of Mathematics. Oxford Second Series 1 Semigroup Forum 1 Zeitschrift für Wahrscheinlichkeitstheorie und Verwandte Gebiete 1 Journal of Beijing Normal University. Natural Science 1 Journal of Complexity 1 International Journal of Mathematics 1 Mathematical Chronicle 1 Proceedings of the National Academy of Sciences of the United States of America 1 Comptes Rendus de l’Académie des Sciences. Série I 1 Far East Journal of Mathematical Sciences 1 The Ramanujan Journal 1 Analysis (München) 1 Analysis in Theory and Applications
all top 5
#### Fields
49 Harmonic analysis on Euclidean spaces (42-XX) 39 Abstract harmonic analysis (43-XX) 28 Measure and integration (28-XX) 19 Number theory (11-XX) 14 Probability theory and stochastic processes (60-XX) 11 Functional analysis (46-XX) 8 Real functions (26-XX) 6 Special functions (33-XX) 6 Dynamical systems and ergodic theory (37-XX) 6 Approximations and expansions (41-XX) 5 Topological groups, Lie groups (22-XX) 5 Operator theory (47-XX) 1 Group theory and generalizations (20-XX) 1 Functions of a complex variable (30-XX) 1 Difference and functional equations (39-XX) 1 Numerical analysis (65-XX)
#### Citations contained in zbMATH
84 Publications have been cited 523 times in 388 Documents Cited by Year
On the multifractal analysis of measures. Zbl 0892.28006
Brown, G.; Michon, G.; Peyrière, J.
1992
Approximation of smooth functions on compact two-point homogeneous spaces. Zbl 1076.41012
Brown, Gavin; Dai, Feng
2005
Riesz products and generalized characters. Zbl 0325.43003
Brown, Gavin
1975
Kolmogorov width of classes of smooth functions on the sphere $$\mathbb S^{d-1}$$. Zbl 1036.41012
Brown, Gavin; Feng, Dai; Sheng, Sun Yong
2002
Multivariate Hausdorff operators on the spaces $$L^p(\mathbb R^n)$$. Zbl 1027.47024
Brown, Gavin; Móricz, Ferenc
2002
On orthogonality of Riesz products. Zbl 0282.43001
Brown, Gavin; Moran, William
1974
Riesz products and normal numbers. Zbl 0574.10051
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1985
Properties of certain trigonometric series arising in numerical analysis. Zbl 0753.42008
Brown, Gavin; Chandler, G. A.; Sloan, Ian H.; Wilson, David C.
1991
Idempotents of compact monothetic semigroups. Zbl 0215.49002
Brown, G.; Moran, W.
1971
Positivity of some basic cosine sums. Zbl 0792.42002
Brown, Gavin; Wang, Kun-Yang; Wilson, David C.
1993
A dichotomy for infinite convolutions of discrete measures. Zbl 0247.43002
Brown, G.; Moran, W.
1973
Odometer actions on $$G$$-measures. Zbl 0739.58032
Brown, Gavin; Dooley, Anthony H.
1991
Riesz products, Hausdorff dimension and normal numbers. Zbl 0625.10043
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1987
Point derivations on M(G). Zbl 0321.43003
Brown, Gavin; Moran, William
1976
Extensions of Vietoris’s inequalities I. Zbl 1138.26009
Brown, Gavin; Dai, Feng; Wang, Kunyang
2007
A class of positive trigonometric sums. Zbl 0522.42001
Brown, Gavin; Hewitt, Edwin
1984
Raikov systems and radicals in convolution measure algebras. Zbl 0545.43003
Brown, Gavin; Moran, William
1983
On the Silov boundary of a measure algebra. Zbl 0221.43005
Brown, G.; Moran, W.
1971
The Hausdorff and the quasi Hausdorff operators on the spaces $$L^p$$, $$1\leq p<\infty$$. Zbl 0952.47028
Brown, Gavin; Móricz, Ferenc
2000
Continuous singular measures with small Fourier-Stieltjes transforms. Zbl 0445.42004
Brown, G.; Hewitt, E.
1980
Singular infinitely divisible distributions whose characteristic functions vanish at infinity. Zbl 0366.60021
Brown, Gavin
1977
Products of random variables and Kakutani’s criterion for orthogonality of product measures. Zbl 0311.60016
Brown, Gavin; Moran, William
1975
Coin tossing and powers of singular measures. Zbl 0307.60046
Brown, Gavin; Moran, William
1975
Positivity of a class of cosine sums. Zbl 0980.42003
Brown, Gavin; Yin, Qinghe
2001
On $$G$$-measures and product measures. Zbl 0919.28014
Brown, Gavin; Dooley, A. H.
1998
Jacobi polynomial estimates and Fourier-Laplace convergence. Zbl 0909.42017
Brown, Gavin; Wang, Kunyang
1997
On the Krieger-Araki-Woods ratio set. Zbl 0836.28008
Brown, Gavin; Dooley, Anthony H.; Lake, Jane
1995
A decomposition theorem for numbers in which the summands have prescribed normality properties. Zbl 0599.10046
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1986
Bernoulli measure algebras. Zbl 0278.43004
Brown, Gavin; Moran, William
1974
The idempotent semigroups of compact monothetic semigroups. Zbl 0296.22004
Brown, G.; Moran, W.
1972
On positive cosine sums. Zbl 1148.42003
Brown, Gavin; Dai, Feng; Wang, Kunyang
2007
$$\beta$$-transformation, natural extension and invariant measure. Zbl 0960.28009
Brown, Gavin; Yin, Qinghe
2000
Normality with respect to powers of a base. Zbl 0887.11033
Brown, G.; Moran, W.; Pollington, A. D.
1997
Normality to non-integer bases. Zbl 0784.11037
Brown, Gavin; Moran, William; Pollington, Andrew D.
1993
Ergodic measures are of weak product type. Zbl 0586.28015
Brown, Gavin; Dooley, A. H.
1985
Lognormal genesis. Zbl 0462.60094
Brown, Gavin; Sanders, J. W.
1981
Positivity and boundedness of trigonometric sums. Zbl 1150.42004
Brown, Gavin
2007
On the positivity of some basic Legendre polynomial sums. Zbl 0935.33009
Brown, Gavin; Koumandos, Stamatis; Wang, Kunyang
1999
On a monotonic trigonometric sum. Zbl 0869.42002
Brown, Gavin; Koumandos, Stamatis
1997
Metrical theory for Farey continued fractions. Zbl 0880.11057
Brown, Gavin; Yin, Qinghe
1996
Positivity of more Jacobi polynomial sums. Zbl 0847.33006
Brown, Gavin; Koumandos, Stamatis; Wang, Kunyang
1996
Dichotomy theorems for $$G$$-measures. Zbl 0874.28005
Brown, G.; Dooley, A. H.
1994
An inequality, with applications to Cantor measures and normal numbers. Zbl 0662.28007
Brown, Gavin; Keane, Michael S.; Moran, William; Pearce, Charles E. M.
1988
M$$_0$$(G)-boundaries are M(G)-boundaries. Zbl 0294.43005
Brown, Gavin; Moran, William
1975
M$$_0$$(G) has a symmetric maximal ideal off the Silov boundary. Zbl 0279.43004
Brown, Gavin
1973
L-ideals of M(G) determined by continuity of translation. Zbl 0267.43006
Brown, Gavin; Moran, William
1973
Spectra of independent power measures. Zbl 0257.43002
Bailey, W. J.; Brown, G.; Moran, W.
1972
Idempotents in the closure of the characters. Zbl 0247.43016
Brown, Gavin
1972
Positivity of basic sums of ultraspherical polynomials. Zbl 0917.33005
Brown, Gavin; Koumandos, Stamatis; Wang, Kun-Yang
1998
Positivity of Cotes numbers at more Jacobi abscissas. Zbl 0860.33005
Brown, Gavin; Koumandos, Stamatis; Wang, Kun-Yang
1996
Schmidt’s conjecture on normality for commuting matrices. Zbl 0773.11049
Brown, Gavin; Moran, William
1993
A class of positive trigonometric sums. II. Zbl 0663.42002
Brown, Gavin; Wilson, David C.
1989
Indicator functions with large Fourier transforms. Zbl 0521.43004
Brown, Gavin; Glicksberg, Irving; Hewitt, Edwin
1983
Some new singular Fourier-Stieltjes series. Zbl 0423.42008
Brown, Gavin; Hewitt, Edwin
1978
An unusual compact monothetic semigroup. Zbl 0237.22003
Brown, G.; Moran, W.
1971
Norm properties of a class of semi-algebras. Zbl 0164.15602
Brown, Gavin
1969
Type 0 semi-algebras in Banach algebras. Zbl 0155.45802
Brown, Gavin
1968
Symmetric Cantor measure, coin-tossing and sum sets. Zbl 1208.28002
Brown, Gavin
2010
The maximal Riesz, Fejér, and Cesàro operators on real Hardy spaces. Zbl 1062.42003
Brown, Gavin; Feng, Dai; Móricz, Ferenc
2004
Lebesgue measure of sum sets – the basic result for coin-tossing. Zbl 1063.60005
Brown, Gavin; Yin, Qinghe
2004
Strong approximation by Fourier-Laplace series on the unit sphere $$\mathbf S^{n-1}$$. Zbl 1050.42017
Brown, G.; Dai, F.; Móricz, F.
2004
Schmidt’s conjecture on normality for dimension two. Zbl 1045.11053
Brown, Gavin; Moran, William; Pollington, Andrew D.
2002
$$\beta$$-expansions and frequency of zero. Zbl 0963.11041
Brown, Gavin; Yin, Qinghe
1999
A new bound for the Fejér-Jackson sum. Zbl 0912.42001
Brown, G.; Koumandos, S.
1998
On a conjecture of F. Móricz. Zbl 0916.42006
Brown, G.; Wang, K. Y.
1998
An extension of the Fejér-Jackson inequality. Zbl 0882.42001
Brown, Gavin; Wang, Kun-Yang
1997
Approximation by Bochner-Riesz means and Hardy summability. Zbl 0851.42003
Wang, Kunyang; Brown, Gavin
1994
Trigonometric sums and polynomial zeros. Zbl 0671.42009
Brown, Gavin; Wilson, David C.
1988
Some inequalities that arise in measure theory. Zbl 0669.26009
Brown, Gavin
1988
Coin tossing and sum sets. Zbl 0638.60009
Brown, Gavin; Williamson, John H.
1987
Probability measures with trivial Stam groups. Zbl 0496.60007
Brown, Gavin; Moran, William
1982
The asymmetry of M//0(G). Zbl 0493.43001
Brown, G.; Karanikas, C.; Williamson, J. H.
1982
Maximal elements of the maximal ideal space of a measure algebra. Zbl 0401.43003
Brown, Gavin; Moran, William
1980
Analytic discs in the maximal ideal space of M(G). Zbl 0378.43001
Brown, Gavin; Moran, William
1978
Translation and symmetry in M(G). Zbl 0379.43002
Brown, Gavin; Graham, Colin; Moran, William
1977
Sums of random variables in groups and the purity law. Zbl 0293.60011
Brown, Gavin; Moran, William
1974
Lnn(G) is the kernel of the asymmetric maximal ideals of M(G). Zbl 0269.43003
Brown, Gavin; Moran, William
1973
Translation and power independence for Bernoulli convolutions. Zbl 0262.42028
Brown, G.; Moran, W.
1973
In general, Bernoulli convolutions have independent powers. Zbl 0256.43004
Brown, Gavin; Moran, William
1973
Idempotents in compact monothetic semigroups. Zbl 0239.22004
Brown, Gavin; Moran, William
1971
Stability theorems for wedges. Zbl 0219.46024
Brown, Gavin; Pryce, John D.
1971
On convolution measure algebras. Zbl 0191.13902
Brown, Gavin
1970
Stability of wedges and semi-algebras. Zbl 0159.18303
Brown, Gavin
1968
Relatively type O’ semi-algebras. Zbl 0153.44404
Brown, Gavin
1967
Symmetric Cantor measure, coin-tossing and sum sets. Zbl 1208.28002
Brown, Gavin
2010
Extensions of Vietoris’s inequalities I. Zbl 1138.26009
Brown, Gavin; Dai, Feng; Wang, Kunyang
2007
On positive cosine sums. Zbl 1148.42003
Brown, Gavin; Dai, Feng; Wang, Kunyang
2007
Positivity and boundedness of trigonometric sums. Zbl 1150.42004
Brown, Gavin
2007
Approximation of smooth functions on compact two-point homogeneous spaces. Zbl 1076.41012
Brown, Gavin; Dai, Feng
2005
The maximal Riesz, Fejér, and Cesàro operators on real Hardy spaces. Zbl 1062.42003
Brown, Gavin; Feng, Dai; Móricz, Ferenc
2004
Lebesgue measure of sum sets – the basic result for coin-tossing. Zbl 1063.60005
Brown, Gavin; Yin, Qinghe
2004
Strong approximation by Fourier-Laplace series on the unit sphere $$\mathbf S^{n-1}$$. Zbl 1050.42017
Brown, G.; Dai, F.; Móricz, F.
2004
Kolmogorov width of classes of smooth functions on the sphere $$\mathbb S^{d-1}$$. Zbl 1036.41012
Brown, Gavin; Feng, Dai; Sheng, Sun Yong
2002
Multivariate Hausdorff operators on the spaces $$L^p(\mathbb R^n)$$. Zbl 1027.47024
Brown, Gavin; Móricz, Ferenc
2002
Schmidt’s conjecture on normality for dimension two. Zbl 1045.11053
Brown, Gavin; Moran, William; Pollington, Andrew D.
2002
Positivity of a class of cosine sums. Zbl 0980.42003
Brown, Gavin; Yin, Qinghe
2001
The Hausdorff and the quasi Hausdorff operators on the spaces $$L^p$$, $$1\leq p<\infty$$. Zbl 0952.47028
Brown, Gavin; Móricz, Ferenc
2000
$$\beta$$-transformation, natural extension and invariant measure. Zbl 0960.28009
Brown, Gavin; Yin, Qinghe
2000
On the positivity of some basic Legendre polynomial sums. Zbl 0935.33009
Brown, Gavin; Koumandos, Stamatis; Wang, Kunyang
1999
$$\beta$$-expansions and frequency of zero. Zbl 0963.11041
Brown, Gavin; Yin, Qinghe
1999
On $$G$$-measures and product measures. Zbl 0919.28014
Brown, Gavin; Dooley, A. H.
1998
Positivity of basic sums of ultraspherical polynomials. Zbl 0917.33005
Brown, Gavin; Koumandos, Stamatis; Wang, Kun-Yang
1998
A new bound for the Fejér-Jackson sum. Zbl 0912.42001
Brown, G.; Koumandos, S.
1998
On a conjecture of F. Móricz. Zbl 0916.42006
Brown, G.; Wang, K. Y.
1998
Jacobi polynomial estimates and Fourier-Laplace convergence. Zbl 0909.42017
Brown, Gavin; Wang, Kunyang
1997
Normality with respect to powers of a base. Zbl 0887.11033
Brown, G.; Moran, W.; Pollington, A. D.
1997
On a monotonic trigonometric sum. Zbl 0869.42002
Brown, Gavin; Koumandos, Stamatis
1997
An extension of the Fejér-Jackson inequality. Zbl 0882.42001
Brown, Gavin; Wang, Kun-Yang
1997
Metrical theory for Farey continued fractions. Zbl 0880.11057
Brown, Gavin; Yin, Qinghe
1996
Positivity of more Jacobi polynomial sums. Zbl 0847.33006
Brown, Gavin; Koumandos, Stamatis; Wang, Kunyang
1996
Positivity of Cotes numbers at more Jacobi abscissas. Zbl 0860.33005
Brown, Gavin; Koumandos, Stamatis; Wang, Kun-Yang
1996
On the Krieger-Araki-Woods ratio set. Zbl 0836.28008
Brown, Gavin; Dooley, Anthony H.; Lake, Jane
1995
Dichotomy theorems for $$G$$-measures. Zbl 0874.28005
Brown, G.; Dooley, A. H.
1994
Approximation by Bochner-Riesz means and Hardy summability. Zbl 0851.42003
Wang, Kunyang; Brown, Gavin
1994
Positivity of some basic cosine sums. Zbl 0792.42002
Brown, Gavin; Wang, Kun-Yang; Wilson, David C.
1993
Normality to non-integer bases. Zbl 0784.11037
Brown, Gavin; Moran, William; Pollington, Andrew D.
1993
Schmidt’s conjecture on normality for commuting matrices. Zbl 0773.11049
Brown, Gavin; Moran, William
1993
On the multifractal analysis of measures. Zbl 0892.28006
Brown, G.; Michon, G.; Peyrière, J.
1992
Properties of certain trigonometric series arising in numerical analysis. Zbl 0753.42008
Brown, Gavin; Chandler, G. A.; Sloan, Ian H.; Wilson, David C.
1991
Odometer actions on $$G$$-measures. Zbl 0739.58032
Brown, Gavin; Dooley, Anthony H.
1991
A class of positive trigonometric sums. II. Zbl 0663.42002
Brown, Gavin; Wilson, David C.
1989
An inequality, with applications to Cantor measures and normal numbers. Zbl 0662.28007
Brown, Gavin; Keane, Michael S.; Moran, William; Pearce, Charles E. M.
1988
Trigonometric sums and polynomial zeros. Zbl 0671.42009
Brown, Gavin; Wilson, David C.
1988
Some inequalities that arise in measure theory. Zbl 0669.26009
Brown, Gavin
1988
Riesz products, Hausdorff dimension and normal numbers. Zbl 0625.10043
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1987
Coin tossing and sum sets. Zbl 0638.60009
Brown, Gavin; Williamson, John H.
1987
A decomposition theorem for numbers in which the summands have prescribed normality properties. Zbl 0599.10046
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1986
Riesz products and normal numbers. Zbl 0574.10051
Brown, Gavin; Moran, William; Pearce, Charles E. M.
1985
Ergodic measures are of weak product type. Zbl 0586.28015
Brown, Gavin; Dooley, A. H.
1985
A class of positive trigonometric sums. Zbl 0522.42001
Brown, Gavin; Hewitt, Edwin
1984
Raikov systems and radicals in convolution measure algebras. Zbl 0545.43003
Brown, Gavin; Moran, William
1983
Indicator functions with large Fourier transforms. Zbl 0521.43004
Brown, Gavin; Glicksberg, Irving; Hewitt, Edwin
1983
Probability measures with trivial Stam groups. Zbl 0496.60007
Brown, Gavin; Moran, William
1982
The asymmetry of M//0(G). Zbl 0493.43001
Brown, G.; Karanikas, C.; Williamson, J. H.
1982
Lognormal genesis. Zbl 0462.60094
Brown, Gavin; Sanders, J. W.
1981
Continuous singular measures with small Fourier-Stieltjes transforms. Zbl 0445.42004
Brown, G.; Hewitt, E.
1980
Maximal elements of the maximal ideal space of a measure algebra. Zbl 0401.43003
Brown, Gavin; Moran, William
1980
Some new singular Fourier-Stieltjes series. Zbl 0423.42008
Brown, Gavin; Hewitt, Edwin
1978
Analytic discs in the maximal ideal space of M(G). Zbl 0378.43001
Brown, Gavin; Moran, William
1978
Singular infinitely divisible distributions whose characteristic functions vanish at infinity. Zbl 0366.60021
Brown, Gavin
1977
Translation and symmetry in M(G). Zbl 0379.43002
Brown, Gavin; Graham, Colin; Moran, William
1977
Point derivations on M(G). Zbl 0321.43003
Brown, Gavin; Moran, William
1976
Riesz products and generalized characters. Zbl 0325.43003
Brown, Gavin
1975
Products of random variables and Kakutani’s criterion for orthogonality of product measures. Zbl 0311.60016
Brown, Gavin; Moran, William
1975
Coin tossing and powers of singular measures. Zbl 0307.60046
Brown, Gavin; Moran, William
1975
M$$_0$$(G)-boundaries are M(G)-boundaries. Zbl 0294.43005
Brown, Gavin; Moran, William
1975
On orthogonality of Riesz products. Zbl 0282.43001
Brown, Gavin; Moran, William
1974
Bernoulli measure algebras. Zbl 0278.43004
Brown, Gavin; Moran, William
1974
Sums of random variables in groups and the purity law. Zbl 0293.60011
Brown, Gavin; Moran, William
1974
A dichotomy for infinite convolutions of discrete measures. Zbl 0247.43002
Brown, G.; Moran, W.
1973
M$$_0$$(G) has a symmetric maximal ideal off the Silov boundary. Zbl 0279.43004
Brown, Gavin
1973
L-ideals of M(G) determined by continuity of translation. Zbl 0267.43006
Brown, Gavin; Moran, William
1973
Lnn(G) is the kernel of the asymmetric maximal ideals of M(G). Zbl 0269.43003
Brown, Gavin; Moran, William
1973
Translation and power independence for Bernoulli convolutions. Zbl 0262.42028
Brown, G.; Moran, W.
1973
In general, Bernoulli convolutions have independent powers. Zbl 0256.43004
Brown, Gavin; Moran, William
1973
The idempotent semigroups of compact monothetic semigroups. Zbl 0296.22004
Brown, G.; Moran, W.
1972
Spectra of independent power measures. Zbl 0257.43002
Bailey, W. J.; Brown, G.; Moran, W.
1972
Idempotents in the closure of the characters. Zbl 0247.43016
Brown, Gavin
1972
Idempotents of compact monothetic semigroups. Zbl 0215.49002
Brown, G.; Moran, W.
1971
On the Silov boundary of a measure algebra. Zbl 0221.43005
Brown, G.; Moran, W.
1971
An unusual compact monothetic semigroup. Zbl 0237.22003
Brown, G.; Moran, W.
1971
Idempotents in compact monothetic semigroups. Zbl 0239.22004
Brown, Gavin; Moran, William
1971
Stability theorems for wedges. Zbl 0219.46024
Brown, Gavin; Pryce, John D.
1971
On convolution measure algebras. Zbl 0191.13902
Brown, Gavin
1970
Norm properties of a class of semi-algebras. Zbl 0164.15602
Brown, Gavin
1969
Type 0 semi-algebras in Banach algebras. Zbl 0155.45802
Brown, Gavin
1968
Stability of wedges and semi-algebras. Zbl 0159.18303
Brown, Gavin
1968
Relatively type O’ semi-algebras. Zbl 0153.44404
Brown, Gavin
1967
all top 5
#### Cited by 391 Authors
28 Brown, Gavin 24 Dai, Feng 20 Barral, Julien 19 Seuret, Stéphane 17 Moran, William 14 Wang, Heping 12 Sloan, Ian Hugh 9 Wang, Kunyang 8 Dooley, Anthony Haynes 8 Feng, De-Jun 7 Alzer, Horst 7 Koumandos, Stamatis 7 Kwong, Man Kam 6 Graham, Colin C. 5 Duong, Dao Van 5 Fan, Ai Hua 5 Hesse, Kerstin 5 Host, Bernard 5 Jaffard, Stéphane 5 Karanikas, Costas 5 Nguyen Minh Chuong 5 Parreau, François 5 Xu, Yuan 4 Ben Mabrouk, Anouar 4 Bisbas, Antonis 4 Chen, Jiecheng 4 El Abdalaoui, El Houcein 4 Fan, Dashan 4 Heurteaux, Yanick 4 Huang, Hongwei 4 Lin, Shaobo 4 Mhaskar, Hrushikesh N. 4 Simpelaere, Dominique 4 Zhang, Xiongying 3 Aouidi, Jamil 3 Bhouri, Imen 3 Klein, Abel 3 Lau, Anthony To-Ming 3 Lau, Kasing 3 Lévy Véhel, Jacques 3 Liflyand, Elijah 3 Mandelbrot, Benoit B. 3 Mirotin, Adol’f Rubimovich 3 Mortiss, Genevieve 3 Ohrysko, Przemysław 3 Pearce, Charles Edward Miller 3 Pesenson, Isaac Zalmanovich 3 Petrushev, Pencho P. 3 Riedi, Rudolf H. 3 Ritter, Gunter 3 Ruppert, Wolfgang A. F. 3 Volosivets, Sergeĭ Sergeevich 3 Willis, George A. 3 Zhai, Xuebo 2 Bacry, Emmanuel 2 Bertrand-Mathis, Anne 2 Burenkov, Viktor Ivanovich 2 Carey, Alan L. 2 Chandler, Graeme A. 2 Dajani, Karma 2 Dick, Josef 2 Ditzian, Zeev 2 Domínguez, Víctor 2 Doubtsov, Evgueni Sergeevich 2 Duc Duyet, Nguyen 2 Dung, Kieu Huu 2 Dunkl, Charles F. 2 Feng, Han 2 Figueira, Santiago 2 Forrest, Brian E. 2 Hare, Kathryn E. 2 Hewitt, Edwin 2 Hindman, Neil 2 Ivanov, Kamen G. 2 Jin, Xiong 2 Jordão, Thaís 2 Lake, Jane 2 Lemańczyk, Mariusz 2 Loy, Richard J. 2 Ma, Chunsheng 2 MacLean, Alan H. 2 Martinelli, Fabio 2 McLean, William 2 Menegatto, Valdir Antonio 2 Mondal, Saiful Rahman 2 Muzy, Jean-François 2 Narcowich, Francis J. 2 Peron, Ana Paula 2 Peyrière, Jacques 2 Pollington, Andrew Douglas 2 Pym, John S. 2 Queffelec, Martine 2 Ramirez, Donald E. 2 Roginskaya, Maria 2 Sangal, Priyanka 2 Sarnak, Peter Clive 2 Sato, Enji 2 Sheng, Baohuai 2 Shieh, Narn-Rueih 2 Swaminathan, Anbhu ...and 291 more Authors
all top 5
#### Cited in 130 Serials
17 Journal of Functional Analysis 15 Journal of Mathematical Analysis and Applications 14 Israel Journal of Mathematics 14 Mathematical Proceedings of the Cambridge Philosophical Society 13 Communications in Mathematical Physics 13 Advances in Mathematics 13 Proceedings of the American Mathematical Society 13 Ergodic Theory and Dynamical Systems 13 Journal of Complexity 12 Journal of Approximation Theory 12 Semigroup Forum 10 Transactions of the American Mathematical Society 9 Monatshefte für Mathematik 8 Chaos, Solitons and Fractals 8 International Journal of Wavelets, Multiresolution and Information Processing 7 Constructive Approximation 6 Journal of Statistical Physics 6 Tohoku Mathematical Journal. Second Series 5 Annales de l’Institut Fourier 5 Journal of Integral Equations and Applications 5 The Journal of Fourier Analysis and Applications 5 Comptes Rendus. Mathématique. Académie des Sciences, Paris 5 Analysis in Theory and Applications 4 Numerische Mathematik 4 Proceedings of the Edinburgh Mathematical Society. Series II 4 Acta Mathematica Hungarica 3 Journal d’Analyse Mathématique 3 Inventiones Mathematicae 3 Mathematische Annalen 3 Mathematische Zeitschrift 3 Advances in Applied Mathematics 3 Stochastic Processes and their Applications 3 Acta Mathematica Sinica. English Series 3 Journal of the Australian Mathematical Society 3 $$p$$-Adic Numbers, Ultrametric Analysis, and Applications 2 Advances in Applied Probability 2 Analysis Mathematica 2 Lithuanian Mathematical Journal 2 Mathematical Notes 2 Arkiv för Matematik 2 Mathematics of Computation 2 Bulletin de la Société Mathématique de France 2 Journal of Computational and Applied Mathematics 2 Mathematika 2 Publications of the Research Institute for Mathematical Sciences, Kyoto University 2 Results in Mathematics 2 Statistics & Probability Letters 2 Revista Matemática Iberoamericana 2 Journal of Theoretical Probability 2 Journal de Mathématiques Pures et Appliquées. Neuvième Série 2 Applied Mathematics. Series B (English Edition) 2 Applied and Computational Harmonic Analysis 2 Bulletin des Sciences Mathématiques 2 Integral Transforms and Special Functions 2 The Ramanujan Journal 2 Journal of Inequalities and Applications 2 Analysis and Applications (Singapore) 1 Modern Physics Letters A 1 Applicable Analysis 1 Bulletin of the Australian Mathematical Society 1 Computers & Mathematics with Applications 1 Letters in Mathematical Physics 1 Nonlinearity 1 Physics Reports 1 Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg 1 Acta Mathematica 1 Annali di Matematica Pura ed Applicata. Serie Quarta 1 The Annals of Probability 1 Canadian Mathematical Bulletin 1 Compositio Mathematica 1 Duke Mathematical Journal 1 Functional Analysis and its Applications 1 Journal of Computer and System Sciences 1 Journal of the London Mathematical Society. Second Series 1 Journal of Multivariate Analysis 1 Journal of Number Theory 1 Journal of Soviet Mathematics 1 Mathematische Nachrichten 1 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 1 Numerical Functional Analysis and Optimization 1 Ricerche di Matematica 1 Theoretical Computer Science 1 Tokyo Journal of Mathematics 1 Zeitschrift für Wahrscheinlichkeitstheorie und Verwandte Gebiete 1 Combinatorica 1 Chinese Annals of Mathematics. Series B 1 Acta Applicandae Mathematicae 1 Physica D 1 Acta Mathematicae Applicatae Sinica. English Series 1 Journal of Cryptology 1 Forum Mathematicum 1 Science in China. Series A 1 Neural Networks 1 The Annals of Applied Probability 1 The Journal of Geometric Analysis 1 Numerical Algorithms 1 Journal of Contemporary Mathematical Analysis. Armenian Academy of Sciences 1 Aequationes Mathematicae 1 Communications in Statistics. Theory and Methods 1 Proceedings of the Indian Academy of Sciences. Mathematical Sciences ...and 30 more Serials
all top 5
#### Cited in 44 Fields
121 Measure and integration (28-XX) 113 Harmonic analysis on Euclidean spaces (42-XX) 68 Abstract harmonic analysis (43-XX) 55 Probability theory and stochastic processes (60-XX) 51 Dynamical systems and ergodic theory (37-XX) 51 Approximations and expansions (41-XX) 46 Number theory (11-XX) 46 Functional analysis (46-XX) 35 Operator theory (47-XX) 27 Topological groups, Lie groups (22-XX) 27 Real functions (26-XX) 27 Numerical analysis (65-XX) 18 Special functions (33-XX) 8 Functions of a complex variable (30-XX) 8 Integral equations (45-XX) 8 Statistics (62-XX) 7 Partial differential equations (35-XX) 7 Statistical mechanics, structure of matter (82-XX) 6 Computer science (68-XX) 5 General topology (54-XX) 5 Quantum theory (81-XX) 4 Integral transforms, operational calculus (44-XX) 4 Information and communication theory, circuits (94-XX) 3 Combinatorics (05-XX) 3 Sequences, series, summability (40-XX) 3 Fluid mechanics (76-XX) 3 Biology and other natural sciences (92-XX) 2 Mathematical logic and foundations (03-XX) 2 Linear and multilinear algebra; matrix theory (15-XX) 2 Group theory and generalizations (20-XX) 2 Potential theory (31-XX) 2 Operations research, mathematical programming (90-XX) 1 General and overarching topics; collections (00-XX) 1 History and biography (01-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Ordinary differential equations (34-XX) 1 Convex and discrete geometry (52-XX) 1 Differential geometry (53-XX) 1 Algebraic topology (55-XX) 1 Manifolds and cell complexes (57-XX) 1 Global analysis, analysis on manifolds (58-XX) 1 Astronomy and astrophysics (85-XX) 1 Geophysics (86-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX)
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-01-20T13:46:55 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5839925408363342, "perplexity": 9014.971510026067}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703520883.15/warc/CC-MAIN-20210120120242-20210120150242-00588.warc.gz"}
|
http://www.gfdl.noaa.gov/blog/isaac-held/2011/08/
|
# Isaac Held's Blog
## 16. Heat uptake and internal variability
Suppose that most of the global mean surface warming in the past half century was due to internal variability rather than external forcing, contrary to one of the central conclusions in the IPCC/AR4/WG1 Summary for Policymakers. Let’s think about the implications for ocean heat uptake. Considering the past half century in this context is convenient because we have direct, albeit imprecise, estimates of ocean heat uptake over this period.
Set the temperature change in question, $T$, equal to the sum of a forced part and an internal variability part: $T = T_F + T_I$, with $T_F= \xi T$, so $\xi$ is the fraction of the temperature change that is forced. The assumption is that this is a linear superposition of two independent pieces, so I’ll write the heat uptake as $H = H_F + H_I$.
When the surface of the Earth warms due to external forcing, we expect the Earth to take up heat. But what do we expect when the surface warms due to internal variability? Can we use observations of heat uptake to constrain $\xi$?
| 2016-06-27T14:48:34 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 6, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9057340025901794, "perplexity": 862.3362887079215}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-26/segments/1466783396029.85/warc/CC-MAIN-20160624154956-00156-ip-10-164-35-72.ec2.internal.warc.gz"}
|
http://pdglive.lbl.gov/DataBlock.action?node=S071RSG
|
# Limits on Kaluza-Klein Gravitons in Warped Extra Dimensions INSPIRE search
This section places limits on the mass of the first Kaluza-Klein (KK) excitation of the graviton in the warped extra dimension model of Randall and Sundrum. Bounds in parenthesis assume Standard Model fields propagate in the bulk. Experimental bounds depend strongly on the warp parameter, $\mathit k$. See the Extra Dimensions'' review for a full discussion.
Here we list limits for the value of the warp parameter $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1.
VALUE (TeV) CL% DOCUMENT ID TECN COMMENT
$\bf{> 4.1}$ 95 1
2017 AP
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
• • • We do not use the following data for averages, fits, limits, etc. • • •
2
2018 F
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit h}}{{\mathit h}}$
$> 3.11$ 95 3
2017 T
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$> 1.9$ 95 4
2017 W
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit j}}{{\mathit j}}$
5
2017 AK
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ , ${{\mathit Z}}{{\mathit Z}}$
6
2016 AE
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ , ${{\mathit Z}}{{\mathit Z}}$
7
2016 H
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
8
2016 I
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit h}}{{\mathit h}}$
9
2016 R
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ , ${{\mathit Z}}{{\mathit Z}}$
10
2016 BQ
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit h}}{{\mathit h}}$
$>3.3$ 95 11
2016 M
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$>2.66$ 95 12
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
13
2015 AU
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
14
2015 AZ
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$
15
2015 BK
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit h}}{{\mathit h}}$
16
2015 CT
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ , ${{\mathit Z}}{{\mathit Z}}$
$> 2.73$ 95 17
2015 AE
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
18
2015 R
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit h}}{{\mathit h}}$
$> 2.68$ 95 19
2014 V
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
20
2014 A
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ , ${{\mathit Z}}{{\mathit Z}}$ , ${{\mathit W}}{{\mathit Z}}$
$\text{>1.23 (>0.84)}$ 95 21
2013 A
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$
$\text{>0.94 (>0.71)}$ 95 22
2013 AO
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$
$> 2.23$ 95 23
2013 AS
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ , ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$> 2.39$ 95 24
2013 AF
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
25
2013 U
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
$> 0.845$ 95 26
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
$> 2.16$ 95 27
2012 CC
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \ell}}{{\overline{\mathit \ell}}}$
$> 1.95$ 95 28
2012 Y
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ , ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
29
2012 V
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
30
2012
RVUE Electroweak
$> 1.84$ 95 31
2012 R
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$> 1.63$ 95 32
ATLS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \ell}}{{\overline{\mathit \ell}}}$
33
2011 G
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
$> 1.058$ 95 34
2011 R
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$
$> 0.754$ 95 35
2011 H
D0 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$
$> 1.079$ 95 36
2011
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \ell}}{{\overline{\mathit \ell}}}$
$> 0.607$ 37
2010 N
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$
$> 1.05$ 38
2010 F
D0 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$
39
2008 S
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$
$> 0.90$ 40
2008 J
D0 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$
41
2007 G
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$> 0.889$ 42
2007 H
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit e}}{{\overline{\mathit e}}}$
$> 0.785$ 43
2005 N
D0 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \ell}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$
$> 0.71$ 44
2005 A
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit \ell}}{{\overline{\mathit \ell}}}$
1 AABOUD 2017AP use 36.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV in the diphoton channel to place a lower limit on the mass of the lightest KK graviton.
2 SIRUNYAN 2018F use 35.9 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV to search for Higgs boson pair production in the ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit \ell}}{{\mathit \nu}}{{\mathit \ell}}{{\mathit \nu}}$ final state. See their Figure 7 for limits on the cross section times branching fraction as a function of the KK graviton mass with a warp parameter value $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1.
3 KHACHATRYAN 2017T use 2.7 (2.9) fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV in the dielectron (dimuon) channel. This 13 TeV data is combined with 20 fb${}^{-1}$ of a previously analyzed set of 8 TeV data to place a lower bound on the mass of the lightest KK graviton. See their paper for the limit with warp parameter value $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.01.
4 KHACHATRYAN 2017W use 12.9 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV to place a lower bound on the mass of the lightest KK graviton. (The quoted bound is for a warp parameter value of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1, although it was not disclosed in the publication.)
5 SIRUNYAN 2017AK use 19.7 fb${}^{-1}$ and up to 2.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV and 13 TeV, respectively, to place limits on the production cross section of a KK graviton resonance. See their Figure 3 for exclusion limits on the signal strength for $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.5 and a mass range of 0.6 to 4.0 TeV .
6 AABOUD 2016AE use 3.2 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV to place a lower bound on the mass of the lightest KK graviton. See their Figure 8 for the limit on the KK graviton mass as a function of the cross section times branching fraction for $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 1.
7 AABOUD 2016H use 3.2 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV in the diphoton channel to place a lower limit on the mass of the lightest KK graviton. See their Figure 11 for limits on the cross section times branching fraction as a function of the graviton mass with warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.3.
8 AABOUD 2016I use 3.2 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV to search for Higgs boson pair production in the ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}$ final state. See their Figure 10 for limits on the cross section times branching fraction as a function of the KK graviton mass with warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 1.0 and 2.0.
9 AAD 2016R use 20.3 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to place a lower bound on the mass of the lightest KK graviton. See their Figure 4 for the limit on the KK graviton mass as a function of the cross section times branching fraction.
10 KHACHATRYAN 2016BQ use 19.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to search for Higgs boson pair production in the ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit b}}{{\overline{\mathit b}}}$ final state. See their Figure 9 for limits on the cross section times branching fraction as a function of the KK graviton mass with a warp parameter value $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.2.
11 KHACHATRYAN 2016M use 19.7 fb${}^{-1}$ and 3.3 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV and 13 TeV, respectively, in the diphoton channel to place a lower limit on the mass of the lightest KK graviton. See their paper for limits with other warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.01 and 0.2.
12 AAD 2015AD use 20.3 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV in the diphoton channel to place a lower limit on the mass of the lightest KK graviton. See their Table IV for limits with warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1.
13 AAD 2015AU use 20 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to search for KK gravitons in a warped extra dimension decaying to ${{\mathit Z}}{{\mathit Z}}$ dibosons. See their Figure 2 for limits on the KK graviton mass as a function of the cross section times branching fraction.
14 AAD 2015AZ use 20.3 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to place a lower bound on the mass of the lightest KK graviton. See their Figure 2 for limits on the KK graviton mass as a function of the cross section times branching ratio.
15 AAD 2015BK use 19.5 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to search for Higgs boson pair production in the ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}$ final state, and exclude masses of the lightest KK graviton. See their Table 9 for the excluded mass ranges with warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 1.0, 1.5, and 2.0.
16 AAD 2015CT use 20.3 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to place a lower bound on the mass of the lightest KK graviton. See their Figures 6b and 6c for the limit on the KK graviton mass as a function of the cross section times branching fraction.
17 KHACHATRYAN 2015AE use 20.6 (19.7) fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV in the dimuon (dielectron) channel to place a lower bound on the mass of the lightest KK graviton.
18 KHACHATRYAN 2015R use 17.9 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to search for Higgs boson pair production in the ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}$ final state, and exclude a KK graviton with mass from 380 to 830 GeV.
19 AAD 2014V use 20 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV in the dielectron and dimuon channels to place a lower bound on the mass of the lightest KK graviton.
20 KHACHATRYAN 2014A use 19.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV to search for KK gravitons in a warped extra dimension decaying to dibosons. See their Figure 9 for limits on the cross section times branching fraction as a function of the KK graviton mass.
21 AAD 2013A use 4.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the ${{\mathit \ell}}{{\mathit \nu}}{{\mathit \ell}}{{\mathit \nu}}$ channel, to place a lower bound on the mass of the lightest KK graviton.
22 AAD 2013AO use 4.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the ${{\mathit \ell}}{{\mathit \nu}}{{\mathit j}}{{\mathit j}}$ channel, to place a lower bound on the mass of the lightest KK graviton.
23 AAD 2013AS use 4.9 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the diphoton channel to place lower limits on the mass of the lightest KK graviton. The diphoton channel is combined with previous results in the dielectron and dimuon channels to set the best limit. See their Table 2 for warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1.
24 CHATRCHYAN 2013AF use 5.3 and 4.1 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV and 8 TeV, respectively, in the dielectron and dimuon channels, to place a lower bound on the mass of the lightest KK graviton.
25 CHATRCHYAN 2013U use 5 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV to search for KK gravitons in a warped extra dimension decaying to ${{\mathit Z}}{{\mathit Z}}$ dibosons. See their Figure 5 for limits on the lightest KK graviton mass as a function of $\mathit k/{{\overline{\mathit M}}_{{P}}}$.
26 AAD 2012AD use 1.02 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV to search for KK gravitons in a warped extra dimension decaying to ${{\mathit Z}}{{\mathit Z}}$ dibosons in the ${{\mathit l}}{{\mathit l}}{{\mathit j}}{{\mathit j}}$ and ${{\mathit l}}{{\mathit l}}{{\mathit l}}{{\mathit l}}$ channels (${{\mathit \ell}}={{\mathit e}}$, ${{\mathit \mu}}$). The limit is quoted for the combined ${{\mathit l}}{{\mathit l}}{{\mathit j}}{{\mathit j}}$ + ${{\mathit l}}{{\mathit l}}{{\mathit l}}{{\mathit l}}$ channels. See their Figure 5 for limits on the cross section ${\mathit \sigma (}$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}{)}$ as a function of the graviton mass.
27 AAD 2012CC use 4.9 and 5.0 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the dielectron and dimuon channels, respectively, to place a lower bound on the mass of the lightest KK graviton. See their Figure 5 for limits on the lightest KK graviton mass as a function of $\mathit k/{{\overline{\mathit M}}_{{P}}}$.
28 AAD 2012Y use 2.12 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the diphoton channel to place lower limits on the mass of the lightest KK graviton. The diphoton channel is combined with previous results in the dielectron and dimuon channels to set the best limit. See their Table 3 for warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1.
29 AALTONEN 2012V use 6 fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in a warped extra dimension decaying to ${{\mathit Z}}{{\mathit Z}}$ dibosons in the ${{\mathit l}}{{\mathit l}}{{\mathit j}}{{\mathit j}}$ and ${{\mathit l}}{{\mathit l}}{{\mathit l}}{{\mathit l}}$ channels (${{\mathit \ell}}={{\mathit e}}$, ${{\mathit \mu}}$). It provides improved limits over the previous analysis in AALTONEN 2011G. See their Figure 16 for limits from all channels combined on the cross section times branching ratio ${\mathit \sigma (}$ ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit G}^{*}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}{)}$ as a function of the graviton mass.
30 BAAK 2012 use electroweak precision observables to place a lower bound on the compactification scale $\mathit k$ $\mathit e{}^{- {{\mathit \pi}} {{\mathit k}} {{\mathit R}} }$, assuming Standard Model fields propagate in the bulk and the Higgs is confined to the IR brane. See their Fig. 27 for more details.
31 CHATRCHYAN 2012R use 2.2 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the diphoton channel to place lower limits on the mass of the lightest KK graviton. See their Table III for warp parameter values $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1.
32 AAD 2011AD use 1.08 and 1.21 fb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the dielectron and dimuon channels, respectively, to place a lower bound on the mass of the lightest graviton. For warp parameter values ${{\mathit k}}/{{\overline{\mathit M}}_{{P}}}$ between 0.01 to 0.1 the lower limit on the mass of the lightest graviton is between 0.71 and 1.63 TeV. See their Table IV for more details.
33 AALTONEN 2011G use $2.5 - 2.9$ fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in a warped extra dimension decaying to ${{\mathit Z}}{{\mathit Z}}$ dibosons via the ${{\mathit e}}{{\mathit e}}{{\mathit e}}{{\mathit e}}$ , ${{\mathit e}}{{\mathit e}}{{\mathit \mu}}{{\mathit \mu}}$ , ${{\mathit \mu}}{{\mathit \mu}}{{\mathit \mu}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit e}}{{\mathit j}}{{\mathit j}}$ , and ${{\mathit \mu}}{{\mathit \mu}}{{\mathit j}}{{\mathit j}}$ channels. See their Fig. 20 for limits on the cross section ${\mathit \sigma (}$ ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}{)}$ as a function of the graviton mass.
34 AALTONEN 2011R uses 5.7 fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV in the dielectron channel to place a lower bound on the mass of the lightest graviton. It provides combined limits with the diphoton channel analysis of AALTONEN 2011U. For warp parameter values ${{\mathit k}}/{{\overline{\mathit M}}_{{P}}}$ between 0.01 to 0.1 the lower limit on the mass of the lightest graviton is between 612 and 1058 GeV. See their Table I for more details.
35 ABAZOV 2011H use 5.4 fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to place a lower bound on the mass of the lightest graviton. Their 95$\%$ C.L. exclusion limit does not include masses less than 300 GeV.
36 CHATRCHYAN 2011 use 35 and 40 pb${}^{-1}$ of data from ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV in the dielectron and dimuon channels, respectively, to place a lower bound on the mass of the lightest graviton. For a warp parameter value ${{\mathit k}}/{{\overline{\mathit M}}_{{P}}}$ = 0.05, the lower limit on the mass of the lightest graviton is 0.855 TeV.
37 AALTONEN 2010N use 2.9 fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to place a lower bound on the mass of the lightest graviton.
38 ABAZOV 2010F use 5.4 fb${}^{-1}$ of data from ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to place a lower bound on the mass of the lightest graviton. For warp parameter values of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1 the lower limit on the mass of the lightest graviton is between 560 and 1050 GeV. See their Fig. 3 for more details.
39 AALTONEN 2008S use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to four electrons via two ${{\mathit Z}}$ bosons using 1.1 fb${}^{-1}$ of data. See their Fig. 8 for limits on $\sigma \cdot{}$B( ${{\mathit G}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$ ) versus the graviton mass.
40 ABAZOV 2008J use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to electrons and photons using 1 fb${}^{-1}$ of data. For warp parameter values of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ between 0.01 and 0.1 the lower limit on the mass of the lightest excitation is between 300 and 900 GeV. See their Fig. 4 for more details.
41 AALTONEN 2007G use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to photons using 1.2 fb${}^{-1}$ of data. For warp parameter values of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1, 0.05, and 0.01 the bounds on the graviton mass are 850, 694, and 230 GeV, respectively. See their Fig. 3 for more details. See also AALTONEN 2007H.
42 AALTONEN 2007H use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to electrons using 1.3 fb${}^{-1}$ of data. For a warp parameter value of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1 the bound on the graviton mass is 807 GeV. See their Fig. 4 for more details. A combined analysis with the diphoton data of AALTONEN 2007G yields for $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1 a graviton mass lower bound of 889 GeV.
43 ABAZOV 2005N use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to muons, electrons or photons, using 260~pb${}^{-1}$ of data. For warp parameter values of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1, 0.05, and 0.01, the bounds on the graviton mass are 785, 650 and 250$~$GeV respectively. See their Fig.$~$3 for more details.
44 ABULENCIA 2005A use ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV to search for KK gravitons in warped extra dimensions. They search for graviton resonances decaying to muons or electrons, using 200~pb${}^{-1}$ of data. For warp parameter values of $\mathit k/{{\overline{\mathit M}}_{{P}}}$ = 0.1, 0.05, and 0.01, the bounds on the graviton mass are 710, 510 and 170 GeV respectively.
References:
SIRUNYAN 2018F
JHEP 1801 054 Search for Resonant and Nonresonant Higgs Boson Pair Production in the ${\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}{{\mathit \ell}}{{\mathit \nu}}{{\mathit \ell}}{{\mathit \nu}}$ Final State in Proton-Proton Collisions at $\sqrt {s }$ = 13 TeV
AABOUD 2017AP
PL B775 105 Search for New Phenomena in High-Mass Diphoton Final States using 37 ${\mathrm {fb}}{}^{-1}$ of Proton-Proton Collisions Collected at $\sqrt {s }$ = 13 TeV with the ATLAS Detector
KHACHATRYAN 2017W
PL B769 520 Search for Dijet Resonances in Proton-Proton Collisions at $\sqrt {s }$ = 13 TeV and Constraints on Dark Matter and other Models
KHACHATRYAN 2017T
PL B768 57 Search for Narrow Resonances in Dilepton Mass Spectra in Proton-Proton Collisions at $\sqrt {s }$ = 13 TeV and Combination with 8 TeV Data
SIRUNYAN 2017AK
PL B774 533 Combination of Searches for Heavy Resonances Decaying to ${{\mathit W}}{{\mathit W}}$, ${{\mathit W}}{{\mathit Z}}$, ${{\mathit Z}}{{\mathit Z}}$, ${{\mathit W}}{{\mathit H}}$, and ${{\mathit Z}}{{\mathit H}}$ Boson Pairs in Proton-Proton Collisions at $\sqrt {s }$ = 8 and 13 TeV
AABOUD 2016AE
JHEP 1609 173 Searches for Heavy Diboson Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 13 TeV with the ATLAS Detector
AABOUD 2016I
PR D94 052002 Search for Pair Production of Higgs Bosons in the ${\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}{\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Final State using Proton-Proton Collisions at $\sqrt {s }$ = 13 TeV with the ATLAS Detector
AABOUD 2016H
JHEP 1609 001 Search for Resonances in Diphoton Events at $\sqrt {s }$ = 13 TeV with the ATLAS Detector
PL B755 285 Combination of Searches for ${{\mathit W}}{{\mathit W}}$, ${{\mathit W}}{{\mathit Z}}$, and ${{\mathit Z}}{{\mathit Z}}$ Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
KHACHATRYAN 2016M
PRL 117 051802 Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at $\sqrt {s }$ = 8 and 13 TeV
KHACHATRYAN 2016BQ
PR D94 052012 Search for Two Higgs Bosons in Final States Containing Two Photons and Two Bottom Quarks in Proton-Proton Collisions at 8 TeV
PR D92 032004 Search for High-Mass Diphoton Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
JHEP 1512 055 Search for High-Mass Diboson Resonances with Boson-Tagged Jets in Proton-Proton Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
EPJ C75 209 Search for Production of ${{\mathit W}}{{\mathit W}}/{{\mathit W}}{{\mathit Z}}$ Resonances Decaying to a Lepton, Neutrino and Jets in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
EPJ C75 412 Search for Higgs Boson Pair Production in the ${\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}{\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Final State from ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
EPJ C75 69 Search for Resonant Diboson Production in the ${{\mathit \ell}}{{\mathit \ell}}{\mathit {\mathit q}}{\mathit {\overline{\mathit q}}}$ Final State in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
KHACHATRYAN 2015AE
JHEP 1504 025 Search for Physics Beyond the Standard Model in Dilepton Mass Spectra in Proton-Proton Collisions at $\sqrt {s }$ = 8 TeV
KHACHATRYAN 2015R
PL B749 560 Search for Resonant Pair Production of Higgs Bosons Decaying to Two Bottom Quark-Antiquark Pairs in Proton-Proton Collisions at 8 TeV
PR D90 052005 Search for High-Mass Dilepton Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
KHACHATRYAN 2014A
JHEP 1408 174 Search for Massive Resonances Decaying into Pairs of Boosted Bosons in Semi-Leptonic Final States at $\sqrt {s }$ = 8 TeV
NJP 15 043007 Search for Extra Dimensions in Diphoton Events Using Proton$−$Proton Collisions Recorded at $\sqrt {s }$ = 7 TeV with the ATLAS Detector at the LHC
PR D87 112006 Search for Resonant Diboson Production in the ${{\mathit \ell}}{{\mathit \nu}}{{\mathit j}}{{\mathit j}}$ Decay Channels with the ATLAS Detector at 7 TeV
PL B718 860 Search for New Phenomena in the ${{\mathit W}}$ ${{\mathit W}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}{{\mathit \ell}^{\,'}}{{\mathit \nu}^{\,'}}$ Final State in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
CHATRCHYAN 2013U
JHEP 1302 036 Search for Exotic Resonances Decaying into ${{\mathit W}}{{\mathit Z}}/{{\mathit Z}}{{\mathit Z}}$ in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
CHATRCHYAN 2013AF
PL B720 63 Search for Heavy Narrow Dilepton Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV and $\sqrt {s }$ = 8 TeV
PL B712 331 Search for New Particles Decaying to ${{\mathit Z}}{{\mathit Z}}$ using Final States with Leptons and Jets with the ATLAS Detector in $\sqrt {s }$ = 7 TeV Proton$−$Proton Collisions
JHEP 1211 138 Search for High-Mass Resonances Decaying to Dilepton Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
PL B710 538 Search for Extra Dimensions using Diphoton Events in 7 TeV Proton$−$Proton Collisions with the ATLAS Detector
AALTONEN 2012V
PR D85 012008 Search for High-Mass Resonances Decaying into ${{\mathit Z}}{{\mathit Z}}$ in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
BAAK 2012
EPJ C72 2003 Updated Status of the Global Electroweak Fit and Constraints on New Physics
CHATRCHYAN 2012R
PRL 108 111801 Search for Signatures of Extra Dimensions in the Diphoton Mass Spectrum at the Large Hadron Collider
PRL 107 272002 Search for Dilepton Resonances in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
AALTONEN 2011R
PRL 107 051801 Search for New Dielectron Resonances and Randall-Sundrum Gravitons at the Collider Detector at Fermilab
AALTONEN 2011G
PR D83 112008 Search for New Heavy Particles Decaying to ${{\mathit Z}}{{\mathit Z}}$ --> $\mathit llll$, $\mathit lljj$ in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
ABAZOV 2011H
PRL 107 011801 Search for Resonant ${{\mathit W}}{{\mathit W}}$ and ${{\mathit W}}{{\mathit Z}}$ Production in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
CHATRCHYAN 2011
JHEP 1105 093 Search for Resonances in the Dilepton Mass Distribution in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
AALTONEN 2010N
PRL 104 241801 Search for ${{\mathit W}}{{\mathit W}}$ and ${{\mathit W}}{{\mathit Z}}$ Resonances Decaying to Electron, Missing $\mathit E_{T}$, and Two Jets in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
ABAZOV 2010F
PRL 104 241802 Search for Randall-Sundrum Gravitons in the Dielectron and Diphoton Final States with 5.4 fb${}^{-1}$ of Data from ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96$~$TeV
AALTONEN 2008S
PR D78 012008 Search for New Heavy Particles Decaying to ${{\mathit Z}^{0}}$ ${{\mathit Z}^{0}}$ $\rightarrow$ ${{\mathit e}}{{\mathit e}}{{\mathit e}}{{\mathit e}}$ in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
ABAZOV 2008J
PRL 100 091802 Search for Randall-Sundrum Gravitons with 1 ${\mathrm {fb}}{}^{-1}$ of Data from ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
AALTONEN 2007G
PRL 99 171801 Search for High-Mass Diphoton States and Limits on Randall-Sundrum Gravitons at CDF
AALTONEN 2007H
PRL 99 171802 Search for New Physics in High-Mass Electron-Positron Events in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
ABAZOV 2005N
PRL 95 091801 Search for Randall-Sundrum Gravitons in Dilepton and Diphoton Final States
ABULENCIA 2005A
PRL 95 252001 Search for New High-Mass Particles Decaying to Lepton Pairs in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ =1.96 TeV
| 2019-04-22T12:11:35 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9663291573524475, "perplexity": 1382.3187326406864}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-18/segments/1555578553595.61/warc/CC-MAIN-20190422115451-20190422141451-00201.warc.gz"}
|
http://mathonline.wikidot.com/the-number-of-positive-divisors-of-an-integer
|
The Number of Positive Divisors of an Integer
Table of Contents
# The Number of Positive Divisors of an Integer
We will now begin to look at some very important functions in number theory. The first is the number of positive divisors function which we define below.
Definition: Let $n \in \mathbb{Z}$. The function $d : \mathbb{Z} \to \mathbb{N}$ defined by $\displaystyle{d(n) = \sum_{d \mid n}_{d > 0} 1}$ is the Number of Positive Divisors Function.
For conventional purposes we define $d(0) = \infty$. Furthermore, note that $d(n) = d(-n)$ for all $n \in \mathbb{Z}$, so we will often times only make mention of $d(n)$ for $n \in \mathbb{N}$.
For example, let $n = 18$. Then the positive divisors of $n$ are $1$, $2$, $3$, $6$, $9$, and $18$. There are $6$ of them, and so $d(18) = 6$.
We will now look at some results regarding the number of positive divisors of an integer.
Proposition 1: Let $p \in \mathbb{N}$. Then $p$ is prime if and only if $d(p) = 2$.
• Proof: $\Rightarrow$ Suppose that $p$ is prime. Then the only positive divisors of $p$ are $1$ and $p$ by definition, so $d(p) = 2$.
• $\Leftarrow$ Conversely, suppose that $d(p) = 2$. Then we must have that $1$ and $p$ are the only divisors of $p$, i.e., $p$ is prime. $\blacksquare$
Proposition 2: Let $p \in \mathbb{N}$ be a prime number. Then $d(p^2) = 3$.
• Proof: Let $p$ be prime. Then the positive divisors of $p^2$ are $1$, $p$, and $p^2$ (all of which values are distinct) and there exists no other positive divisors since $p^2$ can be factored into $p^2 = p \cdot p$ and we have already covered all divisors of the factors of $p^2$. So $d(p^2) = 3$. $\blacksquare$
Proposition 3: Let $p \in \mathbb{N}$ be a prime number. Then for all $n \in \mathbb{N}$, $d(p^n) = n + 1$.
• Proof: Use Proposition 2 and carry out by induction. $\blacksquare$
Proposition 4: Let $p, q \in \mathbb{N}$ be prime numbers. Then $d(pq) = d(p)d(q)$.
• Proof: Let $p, q \in \mathbb{N}$ be prime. Then the positive divisors of $pq$ are $1$, $p$, $q$, and $pq$, so $d(pq) = 4$. But by Proposition 1, since $p$ and $q$ are prime we have that $d(p) = d(q) = 2$, so indeed:
(1)
\begin{align} \quad d(pq) = d(p)d(q) \quad \blacksquare \end{align}
Proposition 5: Let $n \in \mathbb{N}$, $n > 1$, and let $n = p_1^{e_1}p_2^{e_2}...p_k^{e_k}$ be the prime power decomposition of $n$. Then $d(n) = d(p_1^{e_1})d(p_2^{e_2})...d(p_n^{e_n})$.
• Proof: Use Proposition 4 and carry out by induction. $\blacksquare$
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License
| 2021-04-17T03:11:21 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9947460293769836, "perplexity": 74.96078742068792}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038098638.52/warc/CC-MAIN-20210417011815-20210417041815-00157.warc.gz"}
|
https://nroer.gov.in/55ab34ff81fccb4f1d806025/file/590ad75316b51c9bc01830f3
|
Two chambers were connected by a passage on either sides of the tomb. The structure is in ruins. Feroz Shah Tughlaq undertook the charge of repairing the tomb structure.
License:[Source CIET, NCERT ]June 13, 2017, 5:42 p.m.
| 2020-07-02T22:25:58 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9356790781021118, "perplexity": 9608.936877303613}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593655880243.25/warc/CC-MAIN-20200702205206-20200702235206-00280.warc.gz"}
|
https://zbmath.org/authors/?q=ai%3Alalonde.francois
|
# zbMATH — the first resource for mathematics
## Lalonde, François
Compute Distance To:
Author ID: lalonde.francois Published as: Lalonde, F.; Lalonde, Francois; Lalonde, François External Links: MGP · Wikidata
Documents Indexed: 50 Publications since 1981, including 5 Books
all top 5
#### Co-Authors
17 single-authored 11 McDuff, Dusa 4 Hu, Shengda 4 Polterovich, Leonid Viktorovich 3 Pinsonnault, Martin 2 Anjos, Sílvia 2 Cornea, Octav 1 Abreu, Miguel 1 Biran, Paul 1 Eliashberg, Yakov M. 1 Gatien, Daniel 1 Hurtubise, Jacques C. 1 Kerman, Ely 1 Khesin, Boris A. 1 Leclercq, Rémi 1 Payette, Jordan 1 Pestieau, Charles 1 Sabidussi, Gert 1 Savelyev, Yasha 1 Shelukhin, Egor 1 Sikorav, Jean-Claude 1 Teleman, Andrei-Dumitru
all top 5
#### Serials
3 Inventiones Mathematicae 3 Comptes Rendus de l’Académie des Sciences. Série I 3 Geometry & Topology 2 Duke Mathematical Journal 2 Mathematische Annalen 2 Topology 2 Comptes Rendus. Mathématique. Académie des Sciences, Paris 2 African Diaspora Journal of Mathematics 2 CRM Proceedings & Lecture Notes 2 Electronic Research Announcements in Mathematical Sciences 1 Communications in Mathematical Physics 1 Discrete Mathematics 1 Annales de l’Institut Fourier 1 Canadian Journal of Mathematics 1 Commentarii Mathematici Helvetici 1 Journal of Differential Geometry 1 Transactions of the American Mathematical Society 1 Comptes Rendus Mathématiques de l’Académie des Sciences 1 International Journal of Mathematics 1 Geometric and Functional Analysis. GAFA 1 Mémoires de la Société Mathématique de France. Nouvelle Série 1 Mathematical Research Letters 1 Electronic Research Announcements of the American Mathematical Society 1 Annals of Mathematics. Second Series 1 Fields Institute Communications 1 NATO ASI Series. Series C. Mathematical and Physical Sciences 1 NATO Science Series II: Mathematics, Physics and Chemistry 1 Annales Mathématiques du Québec
all top 5
#### Fields
41 Differential geometry (53-XX) 26 Manifolds and cell complexes (57-XX) 16 Dynamical systems and ergodic theory (37-XX) 11 Algebraic topology (55-XX) 11 Global analysis, analysis on manifolds (58-XX) 5 General and overarching topics; collections (00-XX) 2 Quantum theory (81-XX) 1 Combinatorics (05-XX) 1 Computer science (68-XX)
#### Citations contained in zbMATH Open
37 Publications have been cited 368 times in 250 Documents Cited by Year
The geometry of symplectic energy. Zbl 0829.53025
Lalonde, François; McDuff, Dusa
1995
Topological rigidity of Hamiltonian loops and quantum homology. Zbl 0907.58004
Lalonde, François; McDuff, Dusa; Polterovich, Leonid
1999
Lagrangian submanifolds and exact Lagrangians of cotangent bundles. Zbl 0759.53022
Lalonde, François; Sikorav, Jean-Claude
1991
Hofer’s $$L^ \infty$$-geometry: Energy and stability of Hamiltonian flows. II. Zbl 0844.58021
Lalonde, François; McDuff, Dusa
1996
Symplectic structures on fiber bundles. Zbl 1032.53077
Lalonde, François; McDuff, Dusa
2003
The classification of ruled symplectic 4-manifolds. Zbl 0874.57019
Lalonde, François; McDuff, Dusa
1996
$$J$$-curves and the classification of rational and ruled symplectic 4-manifolds. Zbl 0867.53028
Lalonde, François; McDuff, Dusa
1996
Hofer’s $$L^ \infty$$-geometry: Energy and stability of Hamiltonian flows. I. Zbl 0844.58020
Lalonde, François; McDuff, Dusa
1996
The topology of the space of symplectic balls in rational 4-manifolds. Zbl 1063.57023
Lalonde, François; Pinsonnault, Martin
2004
Cluster homology: an overview of the construction and results. Zbl 1113.53052
Cornea, Octav; Lalonde, François
2006
On the flux conjectures. Zbl 0974.53062
Lalonde, François; McDuff, Dusa; Polterovich, Leonid
1998
Symplectic diffeomorphisms as isometries of Hofer’s norm. Zbl 0874.53028
Lalonde, François; Polterovich, Leonid
1997
Holomorphic cylinders with Lagrangian boundaries and Hamiltonian dynamics. Zbl 0966.37031
Gatien, Daniel; Lalonde, François
2000
Isotopy of symplectic balls, Gromov’s radius and the structure of ruled symplectic 4-manifolds. Zbl 0812.53032
Lalonde, François
1994
Length minimizing Hamiltonian paths for symplectically aspherical manifolds. Zbl 1113.53056
Kerman, Ely; Lalonde, François
2003
Local non-squeezing theorems and stability. Zbl 0837.58014
Lalonde, F.; McDuff, D.
1995
Homological Lagrangian monodromy. Zbl 1229.53082
Hu, Shengda; Lalonde, François; Leclercq, Rémi
2011
A relative Seidel morphism and the Albers map. Zbl 1189.53076
Hu, Shengda; Lalonde, François
2010
Stabilisation of symplectic inequalities and applications. Zbl 0955.53048
Lalonde, François; Pestieau, Charles
1999
Lagrangian suppression of double points and symplectic rigidity. Zbl 0815.53042
Lalonde, François
1992
Le problème d’étoiles pour graphes est NP-complèt. Zbl 0458.68025
Lalonde, Francois
1981
Energy and capacities in symplectic topology. Zbl 0939.53002
Lalonde, François
1997
Positive paths in the linear symplectic group. Zbl 0868.58031
Lalonde, François; McDuff, Dusa
1997
The homotopy type of the space of symplectic balls in rational ruled 4-manifolds. Zbl 1171.53054
Anjos, Sílvia; Lalonde, François; Pinsonnault, Martin
2009
Classes caractéristiques isotropes. (Isotropic characteristic classes). Zbl 0662.55009
Lalonde, François
1989
The $$g$$-areas and the commutator length. Zbl 1276.53082
Lalonde, François; Teleman, Andrei
2013
Hamiltonian collapsing of irrational Lagrangian submanifolds with small first Betti numbers. Zbl 0806.58020
Lalonde, François
1992
Homologie de Shih d’une submersion (homologies non singulières des variétés feuilletées). (Shih homology of a submersion (nonsingular homologies of foliated manifolds)). Zbl 0642.57019
Lalonde, François
1987
Smooth covers on symplectic manifolds. Zbl 1425.53110
Lalonde, François; Payette, Jordan
2019
An example concerning Hamiltonian groups of self product. I. Zbl 1283.53079
Hu, Shengda; Lalonde, François
2012
The topology of the space of symplectic balls in $$S^{2}\times S^{2}$$. Zbl 1143.53076
Anjos, Sílvia; Lalonde, François
2007
Lagrangian submanifolds: from the local model to the cluster complex. Zbl 1104.53079
Lalonde, François
2006
A field theory for symplectic fibrations over surfaces. Zbl 1078.53091
Lalonde, François
2004
Automorphism groups and embeddings of symplectic balls into rational manifolds. Zbl 1055.53062
Lalonde, François; Pinsonnault, Martin
2002
$$J$$-holomorphic curves and symplectic invariants (Based on notes taken by Daniel Gatien). Zbl 0870.53021
Lalonde, François
1997
Homologie de Shih d’une submersion. (Shih homology of a submersion). Zbl 0571.57017
Lalonde, François
1984
Homologie de plongements dans les varietés différentiables. (Homology of embeddings in differentiable manifolds). Zbl 0571.57016
Lalonde, François
1984
Smooth covers on symplectic manifolds. Zbl 1425.53110
Lalonde, François; Payette, Jordan
2019
The $$g$$-areas and the commutator length. Zbl 1276.53082
Lalonde, François; Teleman, Andrei
2013
An example concerning Hamiltonian groups of self product. I. Zbl 1283.53079
Hu, Shengda; Lalonde, François
2012
Homological Lagrangian monodromy. Zbl 1229.53082
Hu, Shengda; Lalonde, François; Leclercq, Rémi
2011
A relative Seidel morphism and the Albers map. Zbl 1189.53076
Hu, Shengda; Lalonde, François
2010
The homotopy type of the space of symplectic balls in rational ruled 4-manifolds. Zbl 1171.53054
Anjos, Sílvia; Lalonde, François; Pinsonnault, Martin
2009
The topology of the space of symplectic balls in $$S^{2}\times S^{2}$$. Zbl 1143.53076
Anjos, Sílvia; Lalonde, François
2007
Cluster homology: an overview of the construction and results. Zbl 1113.53052
Cornea, Octav; Lalonde, François
2006
Lagrangian submanifolds: from the local model to the cluster complex. Zbl 1104.53079
Lalonde, François
2006
The topology of the space of symplectic balls in rational 4-manifolds. Zbl 1063.57023
Lalonde, François; Pinsonnault, Martin
2004
A field theory for symplectic fibrations over surfaces. Zbl 1078.53091
Lalonde, François
2004
Symplectic structures on fiber bundles. Zbl 1032.53077
Lalonde, François; McDuff, Dusa
2003
Length minimizing Hamiltonian paths for symplectically aspherical manifolds. Zbl 1113.53056
Kerman, Ely; Lalonde, François
2003
Automorphism groups and embeddings of symplectic balls into rational manifolds. Zbl 1055.53062
Lalonde, François; Pinsonnault, Martin
2002
Holomorphic cylinders with Lagrangian boundaries and Hamiltonian dynamics. Zbl 0966.37031
Gatien, Daniel; Lalonde, François
2000
Topological rigidity of Hamiltonian loops and quantum homology. Zbl 0907.58004
Lalonde, François; McDuff, Dusa; Polterovich, Leonid
1999
Stabilisation of symplectic inequalities and applications. Zbl 0955.53048
Lalonde, François; Pestieau, Charles
1999
On the flux conjectures. Zbl 0974.53062
Lalonde, François; McDuff, Dusa; Polterovich, Leonid
1998
Symplectic diffeomorphisms as isometries of Hofer’s norm. Zbl 0874.53028
Lalonde, François; Polterovich, Leonid
1997
Energy and capacities in symplectic topology. Zbl 0939.53002
Lalonde, François
1997
Positive paths in the linear symplectic group. Zbl 0868.58031
Lalonde, François; McDuff, Dusa
1997
$$J$$-holomorphic curves and symplectic invariants (Based on notes taken by Daniel Gatien). Zbl 0870.53021
Lalonde, François
1997
Hofer’s $$L^ \infty$$-geometry: Energy and stability of Hamiltonian flows. II. Zbl 0844.58021
Lalonde, François; McDuff, Dusa
1996
The classification of ruled symplectic 4-manifolds. Zbl 0874.57019
Lalonde, François; McDuff, Dusa
1996
$$J$$-curves and the classification of rational and ruled symplectic 4-manifolds. Zbl 0867.53028
Lalonde, François; McDuff, Dusa
1996
Hofer’s $$L^ \infty$$-geometry: Energy and stability of Hamiltonian flows. I. Zbl 0844.58020
Lalonde, François; McDuff, Dusa
1996
The geometry of symplectic energy. Zbl 0829.53025
Lalonde, François; McDuff, Dusa
1995
Local non-squeezing theorems and stability. Zbl 0837.58014
Lalonde, F.; McDuff, D.
1995
Isotopy of symplectic balls, Gromov’s radius and the structure of ruled symplectic 4-manifolds. Zbl 0812.53032
Lalonde, François
1994
Lagrangian suppression of double points and symplectic rigidity. Zbl 0815.53042
Lalonde, François
1992
Hamiltonian collapsing of irrational Lagrangian submanifolds with small first Betti numbers. Zbl 0806.58020
Lalonde, François
1992
Lagrangian submanifolds and exact Lagrangians of cotangent bundles. Zbl 0759.53022
Lalonde, François; Sikorav, Jean-Claude
1991
Classes caractéristiques isotropes. (Isotropic characteristic classes). Zbl 0662.55009
Lalonde, François
1989
Homologie de Shih d’une submersion (homologies non singulières des variétés feuilletées). (Shih homology of a submersion (nonsingular homologies of foliated manifolds)). Zbl 0642.57019
Lalonde, François
1987
Homologie de Shih d’une submersion. (Shih homology of a submersion). Zbl 0571.57017
Lalonde, François
1984
Homologie de plongements dans les varietés différentiables. (Homology of embeddings in differentiable manifolds). Zbl 0571.57016
Lalonde, François
1984
Le problème d’étoiles pour graphes est NP-complèt. Zbl 0458.68025
Lalonde, Francois
1981
all top 5
#### Cited by 230 Authors
17 Lalonde, François 14 McDuff, Dusa 13 Polterovich, Leonid Viktorovich 10 Kȩdra, Jarek 6 Ginzburg, Viktor L’vovich 6 Li, Tian-Jun 6 Schlenk, Felix 6 Viña, Andrés 5 Anjos, Sílvia 5 Buhovsky, Lev 5 Leclercq, Rémi 4 Banyaga, Augustin 4 Biran, Paul 4 Cornea, Octav 4 Eliashberg, Yakov M. 4 Gürel, Basak Zehra 4 Oh, Yong-Geun 4 Pelayo, Alvaro 4 Pinsonnault, Martin 4 Savelyev, Yasha 3 Bialy, Misha 3 Brandenbursky, Michael 3 Cho, Yunhyung 3 Fukaya, Kenji 3 Hind, Richard K. 3 Hu, Shengda 3 Milinković, Darko 3 Mundet i Riera, Ignasi 3 Ono, Kaoru 3 Ostrover, Yaron 3 Pedroza, Andrés 3 Seidel, Paul 3 Tralle, Aleksy E. 3 Wu, Weiwei 2 Abbondandolo, Alberto 2 Abreu, Miguel 2 Borman, Matthew Strom 2 Cerf, Jean 2 Cieliebak, Kai 2 Gadbled, Agnès 2 Gal, Światosław R. 2 Gatien, Daniel 2 Gong, Wenmin 2 Hajduk, Bogusław 2 Han, Zhigang 2 Katić, Jelena 2 Kerman, Ely 2 Lu, Guangcun 2 Niglio, Louis 2 Pitiş, Gheorghe 2 Ruan, Yongbin 2 Rudyak, Yuli B. 2 Salamon, Dietmar Arno 2 Sandon, Sheila 2 Shelukhin, Egor 2 Siburg, Karl Friedrich 2 Slimowitz, Jennifer 2 Smith, Ivan 2 Stevenson, Bret 2 Sugimoto, Yoshihiro 2 Swoboda, Jan 2 Usher, Michael 2 Vũ Ngọc, San 2 Ziltener, Fabian 1 Álvarez Gavela, Daniel 1 Barraud, Jean-François 1 Benedetti, Gabriele 1 Bhupal, Mohan 1 Bottman, Nathaniel 1 Buşe, Olguţa 1 Buss, Guy 1 Campos-Apanco, Carlos 1 Casals, Roger 1 Chantraine, Baptiste 1 Charest, François 1 Charette, François 1 Charles, Laurent 1 Chassé, Jean-Philippe 1 Chekanov, Yu. V. 1 Chiang, River 1 Cho, Cheol-Hyun 1 Cho, Yong Seung 1 Çineli, Erman 1 Coffey, Joseph 1 Czarnecki, Andrzej 1 Dai, Bo 1 Damian, Mihai 1 Davis, Donald M. 1 Dimitroglou Rizell, Georgios 1 Donato, Paul 1 Eden, Sinan 1 Ekholm, Tobias 1 Entov, Michael 1 Ferreira de Velloso Vianna, Renato 1 Fomin, Fedor V. 1 Frauenfelder, Urs Adrian 1 Giroux, Emmanuel 1 Gonzalez, Eduardo 1 Gordeev, Nikolai L. 1 Granja, Gustavo ...and 130 more Authors
all top 5
#### Cited in 87 Serials
16 Geometry & Topology 14 Algebraic & Geometric Topology 13 Duke Mathematical Journal 9 Israel Journal of Mathematics 9 Mathematische Zeitschrift 9 Selecta Mathematica. New Series 9 Journal of Topology and Analysis 7 Inventiones Mathematicae 7 Transactions of the American Mathematical Society 7 International Journal of Mathematics 6 Proceedings of the American Mathematical Society 6 Differential Geometry and its Applications 6 Communications in Contemporary Mathematics 6 Journal of Fixed Point Theory and Applications 5 Mathematische Annalen 5 Geometric and Functional Analysis. GAFA 5 Comptes Rendus. Mathématique. Académie des Sciences, Paris 4 Journal of Geometry and Physics 4 Compositio Mathematica 4 Geometriae Dedicata 4 Topology and its Applications 4 Annales Mathématiques du Québec 3 Advances in Mathematics 3 Annales de l’Institut Fourier 3 Pacific Journal of Mathematics 2 Rocky Mountain Journal of Mathematics 2 Commentarii Mathematici Helvetici 2 Journal für die Reine und Angewandte Mathematik 2 Michigan Mathematical Journal 2 Proceedings of the Edinburgh Mathematical Society. Series II 2 Annals of Global Analysis and Geometry 2 Journal of the American Mathematical Society 2 The Journal of Geometric Analysis 2 Bulletin of the American Mathematical Society. New Series 2 Mémoires de la Société Mathématique de France. Nouvelle Série 2 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 2 Journal of Algebraic Geometry 2 Journal of the European Mathematical Society (JEMS) 2 International Journal of Geometric Methods in Modern Physics 2 African Diaspora Journal of Mathematics 2 Japanese Journal of Mathematics. 3rd Series 1 Communications in Mathematical Physics 1 Discrete Applied Mathematics 1 Jahresbericht der Deutschen Mathematiker-Vereinigung (DMV) 1 Letters in Mathematical Physics 1 Nonlinearity 1 Russian Mathematical Surveys 1 Arkiv för Matematik 1 Acta Mathematica Vietnamica 1 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 1 Bulletin de la Société Mathématique de France 1 Glasgow Mathematical Journal 1 Journal of Graph Theory 1 Journal of Soviet Mathematics 1 Manuscripta Mathematica 1 Memoirs of the American Mathematical Society 1 Nagoya Mathematical Journal 1 Proceedings of the London Mathematical Society. Third Series 1 Results in Mathematics 1 Theoretical Computer Science 1 Ergodic Theory and Dynamical Systems 1 Physica D 1 Forum Mathematicum 1 Computational Mathematics and Modeling 1 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 1 Indagationes Mathematicae. New Series 1 Experimental Mathematics 1 Calculus of Variations and Partial Differential Equations 1 Journal of Mathematical Sciences (New York) 1 Electronic Research Announcements of the American Mathematical Society 1 Transformation Groups 1 Proceedings of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 1 Annals of Mathematics. Second Series 1 Acta Mathematica Sinica. English Series 1 Annales Henri Poincaré 1 Advances in Geometry 1 Bulletin of the Brazilian Mathematical Society. New Series 1 Journal of Discrete Algorithms 1 SIGMA. Symmetry, Integrability and Geometry: Methods and Applications 1 Journal of Modern Dynamics 1 Journal of Homotopy and Related Structures 1 Journal of Topology 1 Electronic Research Announcements in Mathematical Sciences 1 São Paulo Journal of Mathematical Sciences 1 Kyoto Journal of Mathematics 1 ISRN Geometry 1 Communications in Mathematics and Statistics
all top 5
#### Cited in 27 Fields
208 Differential geometry (53-XX) 108 Manifolds and cell complexes (57-XX) 49 Dynamical systems and ergodic theory (37-XX) 27 Global analysis, analysis on manifolds (58-XX) 24 Algebraic topology (55-XX) 23 Algebraic geometry (14-XX) 15 Several complex variables and analytic spaces (32-XX) 9 Mechanics of particles and systems (70-XX) 7 Topological groups, Lie groups (22-XX) 6 Computer science (68-XX) 5 Combinatorics (05-XX) 4 Category theory; homological algebra (18-XX) 4 Convex and discrete geometry (52-XX) 4 Quantum theory (81-XX) 3 Group theory and generalizations (20-XX) 2 Operator theory (47-XX) 2 Geometry (51-XX) 2 Fluid mechanics (76-XX) 1 Number theory (11-XX) 1 Measure and integration (28-XX) 1 Ordinary differential equations (34-XX) 1 Partial differential equations (35-XX) 1 Abstract harmonic analysis (43-XX) 1 Functional analysis (46-XX) 1 General topology (54-XX) 1 Mechanics of deformable solids (74-XX) 1 Operations research, mathematical programming (90-XX)
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-05-17T11:55:56 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3694361746311188, "perplexity": 9415.210641094465}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991772.66/warc/CC-MAIN-20210517115207-20210517145207-00102.warc.gz"}
|
https://par.nsf.gov/biblio/10067739-characterization-nested-canalyzing-functions-maximum-average-sensitivity
|
A characterization of nested canalyzing functions with maximum average sensitivity
Nested canalyzing functions (NCFs) are a class of Boolean functions which are used to model certain biological phenomena. We derive a complete characterization of NCFs with the largest average sensitivity, expressed in terms of a simple structural property of the NCF. This characterization provides an alternate, but elementary, proof of the tight upper bound on the average sensitivity of any NCF established by Klotz et al. (2013). We also utilize the characterization to derive a closed form expression for the number of NCFs that have the largest average sensitivity.
Authors:
; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10067739
Journal Name:
Discrete applied mathematics
ISSN:
1872-6771
This paper aims to quantify how the lowest halo mass that can be detected with galaxy-galaxy strong gravitational lensing depends on the quality of the observations and the characteristics of the observed lens systems. Using simulated data, we measure the lowest detectable NFW mass at each location of the lens plane, in the form of detailed sensitivity maps. In summary, we find that: (i) the lowest detectable mass Mlow decreases linearly as the signal-to-noise ratio (SNR) increases and the sensitive area is larger when we decrease the noise; (ii) a moderate increase in angular resolution (0.07″ versus 0.09″) and pixel scale (0.01″ versus 0.04″) improves the sensitivity by on average 0.25 dex in halo mass, with more significant improvement around the most sensitive regions; (iii) the sensitivity to low-mass objects is largest for bright and complex lensed galaxies located inside the caustic curves and lensed into larger Einstein rings (i.e rE ≥ 1.0″). We find that for the sensitive mock images considered in this work, the minimum mass that we can detect at the redshift of the lens lies between 1.5 × 108 and $3\times 10^{9}\, \mathrm{M}_{\odot }$. We derive analytic relations between Mlow, the SNR and resolution and discuss themore »
| 2022-12-08T16:38:31 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7082571983337402, "perplexity": 1213.7036815388979}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446711344.13/warc/CC-MAIN-20221208150643-20221208180643-00354.warc.gz"}
|
http://howitallbegan.family/forum/05a987-under-the-bridge-music-theory
|
# under the bridge music theory
is by far the most common internal pattern for strophes. It also, for many people, is the more memorable part of the song. Sciences, Culinary Arts and Personal Online Bachelor's Degree in IT - Visual Communications, How Universities Are Suffering in the Recession & What IT Means to You, Top School in Arlington, VA, for a Computer & IT Security Degree, Top School in Columbia, SC, for IT Degrees, Top School in Lexington, KY, for an IT Degree, Top School in New York City for an International Business Degree, Best Degree Programs in Medical Office Assisting - Des Moines, IA, Top Criminal Justice Administration Degree Program - Albuquerque, NM, Political Risk Analyst Salary Job Description, Competitive Intelligence Analyst Salary Job Description, What is the Bridge of a Song? Study.com has thousands of articles about every In "Longer" by Dan Fogelberg, the second bridge may either be lyrically the same or different than the first bridge and at times it can also be an instrumental part, as in this case. For an example of a strophic song, consider “Blue Suede Shoes” by Carl Perkins. Strict Four-Voice Composition, Partimenti, and Schemata, A brief history of basso continuo keyboard-style voice-leading, Tendency tones and functional harmonic dissonances, Generating Roman numerals from a figured bass line, Galant schemas – The Rule of the Octave and Harmonising the Scale with Sequences, Foundational Concepts for Phrase-level Forms, Expansion and Contraction at the Phrase Level, V. Diatonic Harmony, Tonicization, and Modulation, Introduction to Harmony, Cadences, and Phrase Endings, Strengthening Endings with Strong Pre-dominants, Prolonging Tonic at Phrase Beginnings with V6 and Inverted V7s, Performing Harmonic Analysis Using the Phrase Model, Prolongation at Phrase Beginnings using the Leading-tone Chord, La (scale degree 6) in the bass at beginnings, middles, and endings, Mi (scale degree 3) in the bass at beginnings, Diatonic Sequences in Middles (in progress--no examples yet), Extended Tonicization and Modulation to Closely Related Keys, Introduction to Harmonic Schemas in Pop Music, Pitch Class Sets, Normal Order, and Transformations, Analyzing with Modes, Scales, and Collections. A refrain is most often the last line or so of a section’s text (tail refrain), and occasionally the material at the beginning of a section’s text (head refrain). Once the first AABA cycle is complete, there tend not to be any new lyrics, only repetition of the whole or the end of the main cycle. succeed. A refrain is too short to form its own section—typically a phrase or less. For three-part strophes, the 12-bar blues progression is the most common pattern. An error occurred trying to load this video. Bridges share many traits with the continuation function of classical form. just create an account. That's what bridges do. In the thirty-two bar form of songs, represented as AABA, the A section is repeated three times with the B (the bridge) breaking them up. What do you mean by the balance point of a Carey Foste's Bridge? It's adventurous, but repetitive. Bridges increase the emotional impact of the song by alternating quickly between new information and strong emotional statements. In an AABA song, building expectation for the return of the strophe and arriving on dominant harmony in preparation of that return are essential to bridge function. The tension is generally resolved in the chorus, but the resolution is really only as good as the tension itself. Popular in the first half of the 20th century as a formula for writing music, "AABA" is a type of song structure that has a predictable sequence for songwriting. In "Somewhere Over the Rainbow" by Judy Garland, you can see how the first two verses establish the main melody of the song. The bridge usually uses different chords, a different melody, and the lyrics usually shift. So, where can we expect to find a bridge in popular songs? - Definition & Texture, Operetta: Definition, Composers & Famous Examples, Camelot the Musical: Synopsis, Characters & Songs, The Nutcracker Ballet: Composer, Music & Story, Intertextuality in Music: Definition & Examples, Nikolai Rimsky-Korsakov: Flight of the Bumblebee & Scheherazade, Art, Music, and Architecture Around the World, Biological and Biomedical Category 1: embellishing tones that move by step. Closing rhetoric involves common patterns and techniques that signal that the end of the song is likely coming soon. How Long Does IT Take To Get a PhD in Law? Recommended by The Wall Street Journal [/footnote], Structure of Individual Sections (Simple vs. A simpler song structure common in Western popular music is the verse-chorus model. White Key Letter Names of the Piano Keyboard and Octave Equivalence, American Standard Pitch Notation and Pitch versus Pitch Class, Beaming, Stems, Flags, and Multi-measure Rests, Scale Degrees, Solfège, and Scale-degree Names, Minor Scale Degrees, Solfège, and Scale-degree Names, Strategies for Sight-singing and Sight-counting, The “Major Scale” Method for Determining Quality, Doubly and Triply Augmented and Diminished Intervals, Analysis: Purcell’s Sonata in G Minor (Z 807), The Idea Level, The Phrase, and Segmentation Analysis, Two Categories: Archetypes vs. Jason Summach, “Form in Top-20 Rock Music, 1955–89” (Ph.D. Functional progression takes place on the phrase level within the strophe. This song contains multiple sections, all of which have the same basic underlying music. Visit the Art, Music, and Architecture Around the World page to learn more. However, where “Blue Suede Shoes” followed with an instrumental strophe, The Beatles move to a bridge at 0:52. Auxiliary modules help frame the core modules, introducing them, providing temporary relief from them, or winding down from them. They help you cross something different and get to where you're going. imaginable degree, area of American popular music follows a few basic structures, most of which contain a bridge, a break from the normal pattern that adds excitement. This new section, which brings something of a conclusion (if an open-ended one) to the narrative, gives way to a song-ending outro at 4:54. | {{course.flashcardSetCount}} Chris has a master's degree in history and teaches at the University of Northern Colorado. Your Guide to the Best R&B Singles of 1979. Over 79,000 lessons in all major subjects, {{courseNav.course.mDynamicIntFields.lessonCount}}, What is Dubstep Music? Notation of Notes, Clefs, and Ledger Lines, Half- and Whole-steps, Accidentals, and The Black Keys of the Piano, Major Scales, Scale Degrees, and Key Signatures, Minor Scales, Scale Degrees, and Key Signatures, Introduction to Diatonic Modes and the Chromatic "Scale", The Basics of Sight-singing and Dictation, Roman Numerals and SATB Chord Construction, III. A large-scale song structure, in which the same basic multi-phrase unit is repeated throughout (AAA). School Closures in Virginia Due to Coronavirus: Learning Online in VA When Schools Close, Tech and Engineering - Questions & Answers, Health and Medicine - Questions & Answers, In the circuit below a voltage of V is applied and the variable capacitor C_1 is adjusted until there is zero voltage between a and b. The third section is different, adding a unique twist in the song. Select a subject to preview related courses: Just as the harmonies and melodies of the bridge are different from the usual pattern of the song to build up drama, so are the lyrics. Muse’s “Resistance” is useful for distinguishing between these two terms, since it has both a coda and an outro. A refrain that is the last line or so of a section's text. In this structure, the bridge is easy to find. The bridge gives the song contrast before transitioning to the final A section. AABA form, like strophic form, relies on the strophe to communicate the main lyric and musical ideas of the song, but add in a contrasting bridge section in the middle. Strophic form consists only of repeated strophes.Its form would be abbreviated as AAA. - Definition & Examples, Art & Architecture of the Ancient Middle East, Ancient South American Art & Architecture, DSST Art of the Western World: Study Guide & Test Prep, Introduction to Textiles & the Textile Industry, World Music & Art Lesson Plans & Activities, NES Music - WEST (504): Practice & Study Guide. Somewhere over the rainbow skies are blue, Someday I'll wish upon a star and wake up where the clouds are far behind me. Bridge sections tend to play a transitional role (neither the point from which to depart, nor the point of arrival) in the formal cycle. flashcard set{{course.flashcardSetCoun > 1 ? Then, the return to the last verse provides the listener a comfortable return to what is familiar. AABA consists of at least four sections. ), Writing Half Cadences (using I and V only). Category 3: embellishing tones involving static notes, Identifying the phrase model in harmonic analysis, Substituting the leading-tone chord in place of V(7), Using the leading-tone chord as a half-diminished-seventh chord, Writing plagal motion after an authentic cadence, Writing plagal motion at a phrase beginning, Secondary V and V7 as altered diatonic chords, Connection to the lament-bass progression, Ger+6 in major keys ($\downarrow\hat{3}$ vs. $\uparrow\hat{2}$ – me vs. ri), Deriving a CT°7 chord from multiple neighbor tones, More Networks of Neo-Riemannian Transformations, Applying Chord-Scales to Progressions within a Key, Using the clock face to transpose and invert, Important considerations with collections, The Emergence and Evolution of the Twelve-tone Technique, For the ‘attack-sustain’ (‘resonance’) effect, Recognizing and identifying applied chords, Applied V and V7 as altered diatonic chords, as in “I Want to Be a Cowboy’s Sweetheart” above, Creative Commons Attribution-ShareAlike 4.0 International License.
| 2021-04-18T12:09:22 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.20561328530311584, "perplexity": 6450.660121552738}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038476606.60/warc/CC-MAIN-20210418103545-20210418133545-00532.warc.gz"}
|
https://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MatCreateKAIJ.html
|
petsc-master 2020-01-17
Report Typos and Errors
# MatCreateKAIJ
Creates a matrix type to be used for matrices of the following form:
### Synopsis
#include "petscmat.h"
PetscErrorCode MatCreateKAIJ(Mat A,PetscInt p,PetscInt q,const PetscScalar S[],const PetscScalar T[],Mat *kaij)
[I \otimes S + A \otimes T]
where S is a dense (p \times q) matrix T is a dense (p \times q) matrix A is an AIJ (n \times n) matrix I is the identity matrix The resulting matrix is (np \times nq)
S and T are always stored independently on all processes as PetscScalar arrays in column-major format.
Collective
### Input Parameters
A - the AIJ matrix p - number of rows in S and T q - number of columns in S and T S - the S matrix (can be PETSC_NULL), stored as a PetscScalar array (column-major) T - the T matrix (can be PETSC_NULL), stored as a PetscScalar array (column-major)
### Output Parameter
kaij -the new KAIJ matrix
### Notes
This function increases the reference count on the AIJ matrix, so the user is free to destroy the matrix if it is not needed. Changes to the entries of the AIJ matrix will immediately affect the KAIJ matrix.
MatKAIJSetAIJ(), MatKAIJSetS(), MatKAIJSetT(), MatKAIJGetAIJ(), MatKAIJGetS(), MatKAIJGetT(), MATKAIJ
| 2020-01-19T00:50:02 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.991264283657074, "perplexity": 6179.182404362583}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250593994.14/warc/CC-MAIN-20200118221909-20200119005909-00426.warc.gz"}
|
https://zbmath.org/authors/?q=ai%3Athurston.william-p
|
## Thurston, William Paul
Compute Distance To:
Author ID: thurston.william-p Published as: Thurston, William P.; Thurston, William; Thurston, W. P.; Thurston, Bill; Thurston, W. more...less Homepage: http://www.math.cornell.edu/m/People/Faculty/thurston.html External Links: MacTutor · MGP · Wikidata · Math-Net.Ru · GND · IdRef Awards: Fields Medal (1982)
Documents Indexed: 76 Publications since 1972, including 8 Books 5 Further Contributions Biographic References: 15 Publications Co-Authors: 51 Co-Authors with 52 Joint Publications 1,630 Co-Co-Authors
all top 5
### Co-Authors
28 single-authored 5 Gabai, David 5 Hass, Joel 5 Kerckhoff, Steven P. 4 Farb, Benson 3 Agol, Ian 3 Cannon, James W. 3 Dunfield, Nathan M. 3 Epstein, David Bernard Alper 3 Levy, Silvio V. F. 3 Miller, Gary Lee 3 Teng, Shang-Hua 3 Vavasis, Stephen A. 2 Eliashberg, Yakov Matveevich 2 Gromov, Mikhael Leonidovich 2 Handel, Michael 2 Hatcher, Allen Edward 2 Marden, Albert 2 Milnor, John Willard 2 Plante, Joseph F. 2 Sullivan, Dennis Parnell 2 Tarjan, Robert Endre 1 Almgren, Frederick Justin jun. 1 Baik, Hyungryul 1 Bourguignon, Jean-Pierre 1 Conway, John Horton 1 Cooper, Daryl 1 Coven, Ethan M. 1 Delgado-Friedrichs, Olaf 1 Floyd, William J. 1 Geller, William 1 Grayson, Matthew A. 1 Gunn, Charlie 1 Hirsch, Morris W. 1 Holt, Derek F. 1 Hubbard, John Hamal 1 Huson, Daniel H. 1 Kan, Daniel Marinus 1 Lagarias, Jeffrey C. 1 Lawson, Herbert Blaine jun. 1 Lei, Tan 1 Lindsey, Kathryn A. 1 Park, James K. 1 Paterson, Michael S. 1 Pitici, Mircea 1 Riley, Timothy R. 1 Rosenberg, Harold 1 Silberger, Sylvia 1 Snoeyink, Jack Scott 1 Steiglitz, Kenneth 1 Storm, Peter A. 1 1 Thompson, Abigail A. 1 Thurston, Dylan Paul 1 Vaserstein, Leonid N. 1 Winkelnkemper, Horst Elmar 1 Yan, Gao
all top 5
### Serials
5 Inventiones Mathematicae 5 Topology 4 Annals of Mathematics. Second Series 3 Bulletin of the American Mathematical Society. New Series 3 Geometry & Topology 2 Commentarii Mathematici Helvetici 2 Proceedings of the American Mathematical Society 2 Journal of the American Mathematical Society 2 L’Enseignement Mathématique. 2e Série 2 Bulletin of the American Mathematical Society 2 Astérisque 1 American Mathematical Monthly 1 Classical and Quantum Gravity 1 Israel Journal of Mathematics 1 Beiträge zur Algebra und Geometrie 1 Acta Mathematica 1 Advances in Mathematics 1 Gazette des Mathématiciens 1 Geometriae Dedicata 1 Publications Mathématiques 1 Journal of Differential Geometry 1 Memoirs of the American Mathematical Society 1 Proceedings of the London Mathematical Society. Third Series 1 Transactions of the American Mathematical Society 1 Topology and its Applications 1 Physica D 1 Discrete & Computational Geometry 1 SIAM Journal on Discrete Mathematics 1 Pokroky Matematiky, Fyziky & Astronomie 1 SIAM Journal on Scientific Computing 1 Turkish Journal of Mathematics 1 The Electronic Journal of Combinatorics 1 Journal of the ACM 1 Princeton Mathematical Series 1 University Lecture Series
all top 5
### Fields
51 Manifolds and cell complexes (57-XX) 16 Differential geometry (53-XX) 11 Group theory and generalizations (20-XX) 10 Dynamical systems and ergodic theory (37-XX) 8 Algebraic topology (55-XX) 8 Computer science (68-XX) 7 General and overarching topics; collections (00-XX) 6 Global analysis, analysis on manifolds (58-XX) 5 Functions of a complex variable (30-XX) 5 Geometry (51-XX) 4 Combinatorics (05-XX) 3 History and biography (01-XX) 3 Mathematical logic and foundations (03-XX) 2 Number theory (11-XX) 2 Topological groups, Lie groups (22-XX) 2 Numerical analysis (65-XX) 1 Category theory; homological algebra (18-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Functional analysis (46-XX) 1 Calculus of variations and optimal control; optimization (49-XX) 1 Convex and discrete geometry (52-XX) 1 General topology (54-XX) 1 Fluid mechanics (76-XX)
### Citations contained in zbMATH Open
72 Publications have been cited 4,318 times in 3,654 Documents Cited by Year
On the geometry and dynamics of diffeomorphisms of surfaces. Zbl 0674.57008
Thurston, William P.
1988
Three dimensional manifolds, Kleinian groups and hyperbolic geometry. Zbl 0496.57005
Thurston, William P.
1982
Word processing in groups. Zbl 0764.20017
Epstein, David B. A.; Cannon, James W.; Holt, Derek F.; Levy, Silvio V. F.; Paterson, Michael S.; Thurston, William P.
1992
Three-dimensional geometry and topology. Vol. 1. Ed. by Silvio Levy. Zbl 0873.57001
Thurston, William P.
1997
A norm for the homology of 3-manifolds. Zbl 0585.57006
Thurston, William P.
1986
On iterated maps of the interval. Zbl 0664.58015
Milnor, John; Thurston, William
1988
Some simple examples of symplectic manifolds. Zbl 0324.53031
Thurston, W. P.
1976
Incompressible surfaces in 2-bridge knot complements. Zbl 0602.57002
Hatcher, Allen E.; Thurston, William P.
1985
Hyperbolic structures on 3-manifolds. I: Deformation of acylindrical manifolds. Zbl 0668.57015
Thurston, William P.
1986
Rotation distance, triangulations, and hyperbolic geometry. Zbl 0653.51017
Sleator, Daniel D.; Tarjan, Robert E.; Thurston, William P.
1988
Conway’s tiling groups. Zbl 0714.52007
Thurston, William P.
1990
Hyperbolic geometry and 3-manifolds. Zbl 0483.57007
Thurston, William P.
1982
A presentation for the mapping class group of a closed orientable surface. Zbl 0447.57005
Hatcher, Allen E.; Thurston, William P.
1980
Shapes of polyhedra and triangulations of the sphere. Zbl 0931.57010
Thurston, William P.
1998
Foliations and groups of diffeomorphisms. Zbl 0295.57014
Thurston, William
1974
On the existence of contact forms. Zbl 0312.53028
Thurston, W. P.; Winkelnkemper, H. E.
1975
Confoliations. Zbl 0893.53001
Eliashberg, Yakov M.; Thurston, William P.
1998
A generalization of the Reeb stability theorem. Zbl 0305.57025
Thurston, William P.
1974
Group invariant Peano curves. Zbl 1136.57009
Cannon, James W.; Thurston, William P.
2007
Transformation groups and natural bundles. Zbl 0409.58001
Epstein, D. B. A.; Thurston, W. P.
1979
Pinching constants for hyperbolic manifolds. Zbl 0646.53037
Gromov, Mikhael; Thurston, William P.
1987
Every connected space has the homology of a $$K$$ $$(\pi,1)$$. Zbl 0355.55004
Kan, D. M.; Thurston, W. P.
1976
Separators for sphere-packings and nearest neighbor graphs. Zbl 0883.68100
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1997
Extending holomorphic motions. Zbl 0619.30026
Sullivan, Dennis P.; Thurston, William P.
1986
Existence of codimension-one foliations. Zbl 0347.57014
Thurston, W. P.
1976
On the geometry and dynamics of iterated rational maps. Zbl 1185.37111
Thurston, William P.
2009
Finite covers of random 3-manifolds. Zbl 1111.57013
Dunfield, Nathan M.; Thurston, William P.
2006
Non cobordant foliations of S$$^3$$. Zbl 0266.57004
Thurston, William
1972
New proofs of some results of Nielsen. Zbl 0584.57007
Handel, Michael; Thurston, William P.
1985
On proof and progress in mathematics. Zbl 0817.01031
Thurston, William P.
1994
Travaux de Thurston sur les surfaces. Séminaire Orsay. 2nd ed. Zbl 0731.57001
1991
Lower bounds on volumes of hyperbolic Haken 3-manifolds. Zbl 1155.58016
Agol, Ian; Storm, Peter A.; Thurston, William P.; Dunfield, Nathan
2007
Anosov flows on new three manifolds. Zbl 0435.58019
Handel, Michael; Thurston, William P.
1980
The theory of foliations of codimension greater than one. Zbl 0295.57013
Thurston, William
1974
Characteristic numbers of 3-manifolds. Zbl 0393.57002
Milnor, John W.; Thurston, W.
1977
Travaux de Thurston sur les surfaces. Séminaire Orsay. Zbl 0406.00016
1979
Soliton-like behavior in automata. Zbl 0604.68061
Park, James K.; Steiglitz, Kenneth; Thurston, William P.
1986
Manifolds with canonical coordinate charts: Some examples. Zbl 0529.53025
Sullivan, Dennis; Thurston, William
1983
Non-continuity of the action of the modular group at Bers’ boundary of Teichmüller space. Zbl 0698.32014
Kerckhoff, Steven P.; Thurston, William P.
1990
The virtual Haken conjecture: Experiments and examples. Zbl 1037.57015
Dunfield, Nathan M.; Thurston, William P.
2003
Polynomial growth in holonomy groups of foliations. Zbl 0348.57009
Plante, J. F.; Thurston, W. P.
1976
Anosov flows and the fundamental group. Zbl 0246.58014
Plante, J. F.; Thurston, W. P.
1972
Foliated bundles, invariant measures and flat manifolds. Zbl 0321.57015
Hirsch, Morris W.; Thurston, William P.
1975
The computational complexity of knot genus and spanning area. Zbl 1098.57003
Agol, Ian; Hass, Joel; Thurston, William
2006
Geometric separators for finite-element meshes. Zbl 0914.65123
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1998
Hyperbolic 4-manifolds and conformally flat 3-manifolds. Zbl 0692.57012
Gromov, M.; Lawson, H. Blaine jun.; Thurston, W.
1988
Automatic mesh partitioning. Zbl 0803.68083
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1993
Entropy in dimension one. Zbl 1408.37031
Thurston, William P.
2014
Short encodings of evolving structures. Zbl 0796.68139
Sleator, Daniel D.; Tarjan, Robert E.; Thurston, William P.
1992
On three-dimensional space groups. Zbl 0991.20036
Conway, John H.; Delgado Friedrichs, Olaf; Huson, Daniel H.; Thurston, William P.
2001
Stabilization of Heegaard splittings. Zbl 1177.57018
Hass, Joel; Thompson, Abigail; Thurston, William
2009
Examples of unknotted curves which bound only surfaces of high genus within their convex hulls. Zbl 0353.53001
Almgren, Frederick J. jun.; Thurston, William P.
1977
Earthquakes in two-dimensional hyperbolic geometry. Zbl 0628.57009
Thurston, William P.
1986
The size of spanning disks for polygonal curves. Zbl 1015.57008
Hass, Joel; Snoeyink, Jack; Thurston, William P.
2003
Three dimensional manifolds, Kleinian groups and hyperbolic geometry. Zbl 0528.57009
Thurston, William P.
1983
Solvgroups are not almost convex. Zbl 0687.57018
Cannon, J. W.; Floyd, W. J.; Grayson, M. A.; Thurston, W. P.
1989
On $$K_ 1$$-theory of the Euclidean space. Zbl 0611.18007
Thurston, William P.; Vaserstein, Leonid N.
1986
3-manifold knot genus is NP-complete. Zbl 1192.68305
Agol, Ian; Hass, Joel; Thurston, William
2002
Some remarks on foliations. Zbl 0286.57014
Rosenberg, Harold; Thurston, William P.
1973
On the construction and classification of foliations. Zbl 0332.57014
Thurston, William
1975
Area inequalities for embedded disks spanning unknotted curves. Zbl 1104.53006
Hass, Joel; Lagarias, Jeffrey C.; Thurston, William P.
2004
Two papers: Genera of the arborescent links and A norm for the homology of 3-manifolds. Zbl 1415.57001
Gabai, David; Thurston, William P.
1986
On proof and progress in mathematics. Zbl 1163.00311
Thurston, William P.
2006
A local construction of foliations for three-manifolds. Zbl 0323.57014
Thurston, William P.
1975
Making waves. A guide to the ideas behind Outside In. With an article by Bill Thurston and an afterword by Albert Marden. Zbl 1031.00529
Levy, Silvio
1995
How to see $$3$$-manifolds. Zbl 0932.57017
Thurston, William P.
1998
The absence of efficient dual pairs of spanning trees in planar graphs. Zbl 1097.05015
Riley, T. R.; Thurston, W. P.
2006
Degree-$$d$$-invariant laminations. Zbl 1452.37055
Thurston, William P.; Baik, Hyungryul; Yan, Gao; Hubbard, John H.; Lindsey, Kathryn A.; Lei, Tan; Thurston, Dylan P.
2020
Contact structures and foliations on 3-manifolds. Zbl 0879.57021
Eliashberg, Yakov M.; Thurston, William P.
1996
Triangulating 3-manifolds using 5 vertex link types. Zbl 0656.57004
Cooper, D.; Thurston, W. P.
1988
The theory of foliations of codimension greater than one. Zbl 0316.57013
Thurston, William P.
1975
The symbolic dynamics of tiling the integers. Zbl 1010.37006
Coven, Ethan M.; Geller, William; Silberger, Sylvia; Thurston, William
2002
Degree-$$d$$-invariant laminations. Zbl 1452.37055
Thurston, William P.; Baik, Hyungryul; Yan, Gao; Hubbard, John H.; Lindsey, Kathryn A.; Lei, Tan; Thurston, Dylan P.
2020
Entropy in dimension one. Zbl 1408.37031
Thurston, William P.
2014
On the geometry and dynamics of iterated rational maps. Zbl 1185.37111
Thurston, William P.
2009
Stabilization of Heegaard splittings. Zbl 1177.57018
Hass, Joel; Thompson, Abigail; Thurston, William
2009
Group invariant Peano curves. Zbl 1136.57009
Cannon, James W.; Thurston, William P.
2007
Lower bounds on volumes of hyperbolic Haken 3-manifolds. Zbl 1155.58016
Agol, Ian; Storm, Peter A.; Thurston, William P.; Dunfield, Nathan
2007
Finite covers of random 3-manifolds. Zbl 1111.57013
Dunfield, Nathan M.; Thurston, William P.
2006
The computational complexity of knot genus and spanning area. Zbl 1098.57003
Agol, Ian; Hass, Joel; Thurston, William
2006
On proof and progress in mathematics. Zbl 1163.00311
Thurston, William P.
2006
The absence of efficient dual pairs of spanning trees in planar graphs. Zbl 1097.05015
Riley, T. R.; Thurston, W. P.
2006
Area inequalities for embedded disks spanning unknotted curves. Zbl 1104.53006
Hass, Joel; Lagarias, Jeffrey C.; Thurston, William P.
2004
The virtual Haken conjecture: Experiments and examples. Zbl 1037.57015
Dunfield, Nathan M.; Thurston, William P.
2003
The size of spanning disks for polygonal curves. Zbl 1015.57008
Hass, Joel; Snoeyink, Jack; Thurston, William P.
2003
3-manifold knot genus is NP-complete. Zbl 1192.68305
Agol, Ian; Hass, Joel; Thurston, William
2002
The symbolic dynamics of tiling the integers. Zbl 1010.37006
Coven, Ethan M.; Geller, William; Silberger, Sylvia; Thurston, William
2002
On three-dimensional space groups. Zbl 0991.20036
Conway, John H.; Delgado Friedrichs, Olaf; Huson, Daniel H.; Thurston, William P.
2001
Shapes of polyhedra and triangulations of the sphere. Zbl 0931.57010
Thurston, William P.
1998
Confoliations. Zbl 0893.53001
Eliashberg, Yakov M.; Thurston, William P.
1998
Geometric separators for finite-element meshes. Zbl 0914.65123
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1998
How to see $$3$$-manifolds. Zbl 0932.57017
Thurston, William P.
1998
Three-dimensional geometry and topology. Vol. 1. Ed. by Silvio Levy. Zbl 0873.57001
Thurston, William P.
1997
Separators for sphere-packings and nearest neighbor graphs. Zbl 0883.68100
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1997
Contact structures and foliations on 3-manifolds. Zbl 0879.57021
Eliashberg, Yakov M.; Thurston, William P.
1996
Making waves. A guide to the ideas behind Outside In. With an article by Bill Thurston and an afterword by Albert Marden. Zbl 1031.00529
Levy, Silvio
1995
On proof and progress in mathematics. Zbl 0817.01031
Thurston, William P.
1994
Automatic mesh partitioning. Zbl 0803.68083
Miller, Gary L.; Teng, Shang-Hua; Thurston, William; Vavasis, Stephen A.
1993
Word processing in groups. Zbl 0764.20017
Epstein, David B. A.; Cannon, James W.; Holt, Derek F.; Levy, Silvio V. F.; Paterson, Michael S.; Thurston, William P.
1992
Short encodings of evolving structures. Zbl 0796.68139
Sleator, Daniel D.; Tarjan, Robert E.; Thurston, William P.
1992
Travaux de Thurston sur les surfaces. Séminaire Orsay. 2nd ed. Zbl 0731.57001
1991
Conway’s tiling groups. Zbl 0714.52007
Thurston, William P.
1990
Non-continuity of the action of the modular group at Bers’ boundary of Teichmüller space. Zbl 0698.32014
Kerckhoff, Steven P.; Thurston, William P.
1990
Solvgroups are not almost convex. Zbl 0687.57018
Cannon, J. W.; Floyd, W. J.; Grayson, M. A.; Thurston, W. P.
1989
On the geometry and dynamics of diffeomorphisms of surfaces. Zbl 0674.57008
Thurston, William P.
1988
On iterated maps of the interval. Zbl 0664.58015
Milnor, John; Thurston, William
1988
Rotation distance, triangulations, and hyperbolic geometry. Zbl 0653.51017
Sleator, Daniel D.; Tarjan, Robert E.; Thurston, William P.
1988
Hyperbolic 4-manifolds and conformally flat 3-manifolds. Zbl 0692.57012
Gromov, M.; Lawson, H. Blaine jun.; Thurston, W.
1988
Triangulating 3-manifolds using 5 vertex link types. Zbl 0656.57004
Cooper, D.; Thurston, W. P.
1988
Pinching constants for hyperbolic manifolds. Zbl 0646.53037
Gromov, Mikhael; Thurston, William P.
1987
A norm for the homology of 3-manifolds. Zbl 0585.57006
Thurston, William P.
1986
Hyperbolic structures on 3-manifolds. I: Deformation of acylindrical manifolds. Zbl 0668.57015
Thurston, William P.
1986
Extending holomorphic motions. Zbl 0619.30026
Sullivan, Dennis P.; Thurston, William P.
1986
Soliton-like behavior in automata. Zbl 0604.68061
Park, James K.; Steiglitz, Kenneth; Thurston, William P.
1986
Earthquakes in two-dimensional hyperbolic geometry. Zbl 0628.57009
Thurston, William P.
1986
On $$K_ 1$$-theory of the Euclidean space. Zbl 0611.18007
Thurston, William P.; Vaserstein, Leonid N.
1986
Two papers: Genera of the arborescent links and A norm for the homology of 3-manifolds. Zbl 1415.57001
Gabai, David; Thurston, William P.
1986
Incompressible surfaces in 2-bridge knot complements. Zbl 0602.57002
Hatcher, Allen E.; Thurston, William P.
1985
New proofs of some results of Nielsen. Zbl 0584.57007
Handel, Michael; Thurston, William P.
1985
Manifolds with canonical coordinate charts: Some examples. Zbl 0529.53025
Sullivan, Dennis; Thurston, William
1983
Three dimensional manifolds, Kleinian groups and hyperbolic geometry. Zbl 0528.57009
Thurston, William P.
1983
Three dimensional manifolds, Kleinian groups and hyperbolic geometry. Zbl 0496.57005
Thurston, William P.
1982
Hyperbolic geometry and 3-manifolds. Zbl 0483.57007
Thurston, William P.
1982
A presentation for the mapping class group of a closed orientable surface. Zbl 0447.57005
Hatcher, Allen E.; Thurston, William P.
1980
Anosov flows on new three manifolds. Zbl 0435.58019
Handel, Michael; Thurston, William P.
1980
Transformation groups and natural bundles. Zbl 0409.58001
Epstein, D. B. A.; Thurston, W. P.
1979
Travaux de Thurston sur les surfaces. Séminaire Orsay. Zbl 0406.00016
1979
Characteristic numbers of 3-manifolds. Zbl 0393.57002
Milnor, John W.; Thurston, W.
1977
Examples of unknotted curves which bound only surfaces of high genus within their convex hulls. Zbl 0353.53001
Almgren, Frederick J. jun.; Thurston, William P.
1977
Some simple examples of symplectic manifolds. Zbl 0324.53031
Thurston, W. P.
1976
Every connected space has the homology of a $$K$$ $$(\pi,1)$$. Zbl 0355.55004
Kan, D. M.; Thurston, W. P.
1976
Existence of codimension-one foliations. Zbl 0347.57014
Thurston, W. P.
1976
Polynomial growth in holonomy groups of foliations. Zbl 0348.57009
Plante, J. F.; Thurston, W. P.
1976
On the existence of contact forms. Zbl 0312.53028
Thurston, W. P.; Winkelnkemper, H. E.
1975
Foliated bundles, invariant measures and flat manifolds. Zbl 0321.57015
Hirsch, Morris W.; Thurston, William P.
1975
On the construction and classification of foliations. Zbl 0332.57014
Thurston, William
1975
A local construction of foliations for three-manifolds. Zbl 0323.57014
Thurston, William P.
1975
The theory of foliations of codimension greater than one. Zbl 0316.57013
Thurston, William P.
1975
Foliations and groups of diffeomorphisms. Zbl 0295.57014
Thurston, William
1974
A generalization of the Reeb stability theorem. Zbl 0305.57025
Thurston, William P.
1974
The theory of foliations of codimension greater than one. Zbl 0295.57013
Thurston, William
1974
Some remarks on foliations. Zbl 0286.57014
Rosenberg, Harold; Thurston, William P.
1973
Non cobordant foliations of S$$^3$$. Zbl 0266.57004
Thurston, William
1972
Anosov flows and the fundamental group. Zbl 0246.58014
Plante, J. F.; Thurston, W. P.
1972
all top 5
### Cited by 3,475 Authors
24 Dehornoy, Patrick 23 Ohshika, Ken’ichi 21 Calegari, Danny Matthew Cornelius 19 McMullen, Curtis Tracy 19 Reid, Alan W. 18 Wang, Shi Cheng 17 Friedl, Stefan 16 Kapovich, Ilya 16 Leininger, Christopher J. 15 Handel, Michael 15 Rémila, Eric 15 Souto, Juan 14 Brock, Jeffrey F. 14 Gabai, David 14 Papadopoulos, Athanase 13 Goldman, William M. 13 González-Meneses, Juan 13 Mj, Mahan 13 Ni, Yi 12 Dunfield, Nathan M. 12 Minsky, Yair N. 12 Motegi, Kimihiko 11 Blokh, Alexander M. 11 Boileau, Michel Charles 11 Cain, Alan J. 11 Choi, Suhyoung 11 Cooper, Daryl 11 Fenley, Sérgio R. 11 Franks, John M. 11 Jiang, Yunping 11 Koberda, Thomas 11 Long, Darren D. 11 Luo, Feng 11 Myasnikov, Alexei G. 11 Parlier, Hugo 11 Zhang, Chaohui 10 Barbot, Thierry 10 Colin, Vincent 10 Ichihara, Kazuhiro 10 Inoguchi, Jun-ichi 10 Oversteegen, Lex G. 10 Šarić, Dragomir 10 Teng, Shang-Hua 10 Teragaito, Masakazu 10 Tresser, Charles 9 Bonahon, Francis 9 Bonatti, Christian 9 Bowden, Jonathan Peter 9 Boyer, Steven 9 Bridson, Martin R. 9 Gebhardt, Volker 9 Hermiller, Susan M. 9 Holt, Derek F. 9 Honda, Ko 9 Kenyon, Richard W. 9 Lackenby, Marc 9 Margalit, Dan 9 Mosher, Lee 9 Purcell, Jessica Shepherd 9 Tillmann, Stephan 8 Alsedà, Lluís 8 Baik, Hyungryul 8 Canary, Richard D. 8 Culler, Marc 8 Etnyre, John B. 8 Frigerio, Roberto 8 Fukui, Kazuhiko 8 Gambaudo, Jean-Marc 8 Hooper, W. Patrick 8 Hubert, Pascal 8 Ito, Tetsuya 8 Lyubich, Mikhail 8 Masur, Howard A. 8 Neumann, Walter David 8 Ozsváth, Peter Steven 8 Shalen, Peter B. 8 Sun, Hongbin 8 Szabo, Zoltan 8 Wiest, Bertold 8 Young, Robert 7 Agol, Ian 7 Aßelmeyer-Maluga, Torsten 7 Birman, Joan S. 7 Burton, Benjamin A. 7 Cleary, Sean 7 Conlon, Lawrence 7 Derbez, Pierre 7 Fernández Rodríguez, Marisa 7 Fujiwara, Koji 7 Funar, Louis 7 Hall, Toby 7 Kapovich, Michael 7 Kazez, William H. 7 Kim, Sang-Hyun 7 Kojima, Sadayoshi 7 Lanneau, Erwan 7 Ma, Jiming 7 Milnor, John Willard 7 Mitra, Sudeb 7 Navas, Andrés ...and 3,375 more Authors
all top 5
### Cited in 417 Serials
160 Geometry & Topology 159 Topology and its Applications 157 Transactions of the American Mathematical Society 133 Proceedings of the American Mathematical Society 126 Geometriae Dedicata 120 Algebraic & Geometric Topology 99 Inventiones Mathematicae 89 Advances in Mathematics 75 Mathematische Annalen 73 Journal of Knot Theory and its Ramifications 69 Annales de l’Institut Fourier 65 Duke Mathematical Journal 61 Ergodic Theory and Dynamical Systems 53 Bulletin of the American Mathematical Society. New Series 52 Journal of Algebra 48 Theoretical Computer Science 47 Mathematische Zeitschrift 44 Israel Journal of Mathematics 41 Communications in Mathematical Physics 40 Geometric and Functional Analysis. GAFA 39 Journal of the American Mathematical Society 35 Discrete & Computational Geometry 34 Journal of Pure and Applied Algebra 31 Annals of Global Analysis and Geometry 27 Mathematical Proceedings of the Cambridge Philosophical Society 26 Acta Mathematica 26 Conformal Geometry and Dynamics 24 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 23 Publications Mathématiques 23 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 23 Groups, Geometry, and Dynamics 22 Osaka Journal of Mathematics 21 International Journal of Mathematics 21 Experimental Mathematics 21 Journal of Mathematical Sciences (New York) 21 Journal of Topology and Analysis 20 International Journal of Algebra and Computation 19 Chaos, Solitons and Fractals 19 Journal of Geometry and Physics 19 Differential Geometry and its Applications 18 Computational Geometry 17 Discrete Mathematics 17 Proceedings of the Japan Academy. Series A 17 European Journal of Combinatorics 16 Information Processing Letters 16 Journal of the Mathematical Society of Japan 15 Journal of Combinatorial Theory. Series A 15 Annals of Mathematics. Second Series 15 Journal of Topology 14 Journal d’Analyse Mathématique 14 Physica D 14 Journal of High Energy Physics 13 Journal of the European Mathematical Society (JEMS) 13 Acta Mathematica Sinica. English Series 12 Compositio Mathematica 12 Journal of Geometry 12 Memoirs of the American Mathematical Society 12 Tôhoku Mathematical Journal. Second Series 11 Discrete Applied Mathematics 11 Journal of Mathematical Physics 11 The Mathematical Intelligencer 11 The Journal of Geometric Analysis 11 Journal of Group Theory 11 Comptes Rendus. Mathématique. Académie des Sciences, Paris 10 Communications in Algebra 10 Journal of Statistical Physics 10 Monatshefte für Mathematik 10 Qualitative Theory of Dynamical Systems 10 Bulletin of the Brazilian Mathematical Society. New Series 10 Journal of Modern Dynamics 9 Michigan Mathematical Journal 9 Chinese Annals of Mathematics. Series B 9 Expositiones Mathematicae 9 International Journal of Bifurcation and Chaos in Applied Sciences and Engineering 9 Discrete and Continuous Dynamical Systems 9 Proceedings of the Steklov Institute of Mathematics 8 Archiv der Mathematik 8 Commentarii Mathematici Helvetici 8 Glasgow Mathematical Journal 8 Journal für die Reine und Angewandte Mathematik 8 Manuscripta Mathematica 8 Semigroup Forum 8 Siberian Mathematical Journal 8 Information and Computation 7 General Relativity and Gravitation 7 Mathematical Notes 7 The Annals of Probability 7 Functional Analysis and its Applications 7 Journal of Functional Analysis 7 Journal of Soviet Mathematics 7 Tokyo Journal of Mathematics 7 St. Petersburg Mathematical Journal 7 Annales Mathématiques Blaise Pascal 7 The Electronic Journal of Combinatorics 7 Selecta Mathematica. New Series 7 Bulletin of the American Mathematical Society 7 Forum of Mathematics, Sigma 7 Arnold Mathematical Journal 6 Bulletin of the Australian Mathematical Society 6 Annali di Matematica Pura ed Applicata. Serie Quarta ...and 317 more Serials
all top 5
### Cited in 58 Fields
1,777 Manifolds and cell complexes (57-XX) 779 Group theory and generalizations (20-XX) 688 Dynamical systems and ergodic theory (37-XX) 652 Differential geometry (53-XX) 373 Functions of a complex variable (30-XX) 284 Computer science (68-XX) 276 Combinatorics (05-XX) 250 Several complex variables and analytic spaces (32-XX) 213 Global analysis, analysis on manifolds (58-XX) 184 Convex and discrete geometry (52-XX) 162 Algebraic topology (55-XX) 161 Topological groups, Lie groups (22-XX) 118 Algebraic geometry (14-XX) 79 Geometry (51-XX) 79 General topology (54-XX) 79 Quantum theory (81-XX) 69 Number theory (11-XX) 57 Relativity and gravitational theory (83-XX) 55 Probability theory and stochastic processes (60-XX) 45 Measure and integration (28-XX) 39 General and overarching topics; collections (00-XX) 39 History and biography (01-XX) 38 Statistical mechanics, structure of matter (82-XX) 37 Partial differential equations (35-XX) 35 Mathematical logic and foundations (03-XX) 34 Numerical analysis (65-XX) 31 Order, lattices, ordered algebraic structures (06-XX) 29 Associative rings and algebras (16-XX) 29 Functional analysis (46-XX) 25 Nonassociative rings and algebras (17-XX) 24 Category theory; homological algebra (18-XX) 23 Biology and other natural sciences (92-XX) 22 Calculus of variations and optimal control; optimization (49-XX) 22 Fluid mechanics (76-XX) 21 Commutative algebra (13-XX) 20 $$K$$-theory (19-XX) 20 Operations research, mathematical programming (90-XX) 19 Real functions (26-XX) 19 Information and communication theory, circuits (94-XX) 15 Mechanics of deformable solids (74-XX) 14 Mechanics of particles and systems (70-XX) 12 Ordinary differential equations (34-XX) 11 Difference and functional equations (39-XX) 10 Linear and multilinear algebra; matrix theory (15-XX) 9 Potential theory (31-XX) 8 Operator theory (47-XX) 7 Abstract harmonic analysis (43-XX) 7 Mathematics education (97-XX) 6 General algebraic systems (08-XX) 6 Special functions (33-XX) 5 Statistics (62-XX) 5 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 5 Systems theory; control (93-XX) 3 Field theory and polynomials (12-XX) 2 Harmonic analysis on Euclidean spaces (42-XX) 2 Optics, electromagnetic theory (78-XX) 2 Geophysics (86-XX) 1 Sequences, series, summability (40-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2022-10-03T15:15:45 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5050589442253113, "perplexity": 6967.810988648854}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337421.33/warc/CC-MAIN-20221003133425-20221003163425-00105.warc.gz"}
|
https://par.nsf.gov/biblio/10338993-production-light-anti-nuclei-pp-collisions-sqrt-tev
|
This content will become publicly available on January 1, 2023
Production of light (anti)nuclei in pp collisions at $$\sqrt{s}$$ = 13 TeV
A bstract Understanding the production mechanism of light (anti)nuclei is one of the key challenges of nuclear physics and has important consequences for astrophysics, since it provides an input for indirect dark-matter searches in space. In this paper, the latest results about the production of light (anti)nuclei in pp collisions at $$\sqrt{s}$$ s = 13 TeV are presented, focusing on the comparison with the predictions of coalescence and thermal models. For the first time, the coalescence parameters B 2 for deuterons and B 3 for helions are compared with parameter-free theoretical predictions that are directly constrained by the femtoscopic measurement of the source radius in the same event class. A fair description of the data with a Gaussian wave function is observed for both deuteron and helion, supporting the coalescence mechanism for the production of light (anti)nuclei in pp collisions. This method paves the way for future investigations of the internal structure of more complex nuclear clusters, including the hypertriton.
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10338993
Journal Name:
Journal of High Energy Physics
Volume:
2022
Issue:
1
ISSN:
1029-8479
1. Abstract The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of $$\text {(anti-)deuterons}$$ (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at $$\sqrt{s}=13$$ s = 13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity ( $${\mathrm {d} N_{ch}/\mathrm {d} \eta } \sim 26$$ dmore »
2. Abstract The study of the production of nuclei and antinuclei in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper, the production of protons, deuterons and $$^{3}\mathrm {He}$$ 3 He and their charge conjugates at midrapidity is studied as a function of the charged-particle multiplicity in inelastic pp collisions at $$\sqrt{s}=5.02$$ s = 5.02 TeV using the ALICE detector. Within the uncertainties, the yields of nuclei in pp collisions at $$\sqrt{s}=5.02$$ s = 5.02 TeV are compatible with those in pp collisions at differentmore »
3. A bstract A measurement of the inclusive b-jet production cross section is presented in pp and p-Pb collisions at $$\sqrt{s_{\mathrm{NN}}}$$ s NN = 5 . 02 TeV, using data collected with the ALICE detector at the LHC. The jets were reconstructed in the central rapidity region |η| < 0 . 5 from charged particles using the anti- k T algorithm with resolution parameter R = 0 . 4. Identification of b jets exploits the long lifetime of b hadrons, using the properties of secondary vertices and impact parameter distributions. The p T -differential inclusive production cross section ofmore »
5. A bstract The transverse momentum ( p T ) differential cross section of the charm-strange baryon $${\Xi}_{\mathrm{c}}^0$$ Ξ c 0 is measured at midrapidity (| y | < 0.5) via its semileptonic decay into e + Ξ − ν e in pp collisions at $$\sqrt{s}$$ s = 5 . 02 TeV with the ALICE detector at the LHC. The ratio of the p T -differential $${\Xi}_{\mathrm{c}}^0$$ Ξ c 0 -baryon and D 0 -meson production cross sections is also reported. The measurements are compared with simulations with different tunes of the PYTHIA 8 eventmore »
| 2022-09-27T14:56:53 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.893758237361908, "perplexity": 1109.8285067441234}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030335034.61/warc/CC-MAIN-20220927131111-20220927161111-00202.warc.gz"}
|
https://pubag.nal.usda.gov/catalog/4799198
|
# PubAg
## Inheritance for economically important traits in popcorn from distinct heterotic groups by Hayman’s diallel
Author:
Silva, V. Q. R., Amaral JÚnior, A. T., Scapim, C. A., Freitas Júnior, S. P., Gonçalves, L. S. A.
Source:
Cereal research communications 2010 v.38 no.2 pp. 272-284
ISSN:
0133-3720
Subject:
agronomic traits, alleles, dominant genes, ears, genetic improvement, genotype, grain yield, heritability, hybrids, overdominance, parents, popcorn, popping, recessive genes, researchers, Brazil
Abstract:
When using genotypes of different heterotic groups, the scarcity of information on the inheritance of traits that are of economic importance to popcorn has hindered the implementation of more appropriate methodologies to obtain higher genetic gains. To date, the diallel of Hayman (1954) has not been used by popcorn researchers, but it has robust properties that can minimize this gap in scientific information. Therefore, ten popcorn lines were used to obtain 45 diallel hybrids, which were evaluated along with their parents and three controls in a randomized complete block design with three replicates at two different locations in the State of Rio de Janeiro, Brazil. Three agronomic traits of interest for the crop were scored based on the Hayman method (1954). The positive correlation between $$\bar Y_{ii}$$ and <i>W</i> <sub>i</sub> + <i>V</i> <sub>i</sub> showed that mostly recessive genes determine the expression of popping expansion (PE). It was concluded that dominant genes are mostly responsible for the trait expression of mean ear weight (EW) and grain yield (GY). A predominance of non-additive genetic effects for EW and GY existed and a prevalence of partial dominance and a high narrow-sense determined heritability for PE. For EW and GY, overdominance predominated and heritabilities were moderate to low. As an interpopulation method, popcorn lines with high concentrations of recessive alleles linked to the expression of PE can provide gains in PE and yield traits.
Agid:
4799198
| 2019-09-22T23:44:13 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.47237440943717957, "perplexity": 11843.693855574546}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514575751.84/warc/CC-MAIN-20190922221623-20190923003623-00467.warc.gz"}
|
https://www.nist.gov/publications/spherical-reference-cavities-ultra-stable-lasers-non-laboratory-environments
|
An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.
The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.
# Spherical Reference Cavities for Ultra-Stable Lasers in Non-Laboratory Environments
Published
### Author(s)
David R. Leibrandt, Michael J. Thorpe, Mark Notcutt, Robert E. Drullinger, Till P. Rosenband, James C. Bergquist
### Abstract
We present an ultra-stable optical cavity design that is insensitive to both vibrations and orientation. The design is based on a spherical cavity spacer which is held rigidly at two points on a diameter of the sphere. Coupling of the support forces to the cavity length is eliminated by holding the sphere at a squeeze insensitive angle'' with respect to the optical axis. Finite element analysis is used to calculate the acceleration sensitivity of the spherical cavity for the ideal geometry ($\le 4(2) \times 10^{-12}$/g for accelerations in any direction) as well as for several varieties of fabrication errors. The spherical cavity acceleration sensitivity is measured with an initial version of the cavity mount to be $4.0(5) \times 10^{-11}$/g, $1.6(3) \times 10^{-10}$/g, and $3.1(1) \times 10^{-10}$/g for accelerations along the vertical and two horizontal directions. This low acceleration sensitivity combined with the orientation insensitivity that comes with a rigid mount indicates that this cavity design could be used for ultra-stable lasers in a non-laboratory environment.
Citation
Optics Express
Volume
19
Issue
4
### Keywords
Laser stabilization, optical resonators, vibration analysis
Created February 14, 2011, Updated February 19, 2017
| 2020-09-21T04:00:08 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2838514447212219, "perplexity": 2913.5928068774597}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400198887.3/warc/CC-MAIN-20200921014923-20200921044923-00155.warc.gz"}
|
https://gea.esac.esa.int/archive/documentation/GDR2/Gaia_archive/chap_datamodel/sec_dm_variability_tables/ssec_dm_vari_rotation_modulation.html
|
# 14.3.6 vari_rotation_modulation
This table describes the solar-like stars with rotational modulation.
Columns description:
solution_id : Solution Identifier (long)
All Gaia data processed by the Data Processing and Analysis Consortium comes tagged with a solution identifier. This is a numeric field attached to each table row that can be used to unequivocally identify the version of all the subsystems that where used in the generation of the data as well as the input data used. It is mainly for internal DPAC use but is included in the published data releases to enable end users to examine the provenance of processed data products. To decode a given solution ID visit https://gaia.esac.esa.int/decoder/solnDecoder.jsp
source_id : Unique source identifier (long)
A unique single numerical identifier of the source obtained from gaia_source (for a detailed description see gaia_source.source_id)
num_segments : Number of segments (int, Dimensionless[see description])
This is the number of time intervals (segments) in which the magnitude and colour time-series are splitted. The segmentation of time-series is needed because the spots due to the stellar magnetic activity have a life-time shorter than the whole Gaia time-series. The rotational modulation induced by spots can therefore be detected only in segments whose duration is comparable with the spots life-time
segments_start_time : Times at which segments start (double, Time[Barycentric JD in TCB - 2455197.5 (day)])
an array filled with the starting times of segments
segments_end_time : Times at which segments end (double, Time[Barycentric JD in TCB - 2455197.5 (day)])
an array filled with the ending times of segments
segments_colour_mag_intercept : Colour-Magnitude Intercept in segments (double, Misc[see description])
a robust linear regression is applied to the points (BP-RP, G) in each segment. This array is filled with the intercepts given by the fitting procedure in the different segments.
segments_colour_mag_intercept_error : Colour-Magnitude Intercept uncertainty in segments (double, Misc[see description])
This array is filled with the uncertainties associated with the intercepts given by the fitting procedure
segments_colour_mag_slope : Colour-Magnitude Slope in segments (double, Misc[see description])
a robust linear regression is applied to the points (BP-RP, G) in each segment. This array is filled with the slopes given by the fitting procedure in the different segments.
segments_colour_mag_slope_error : Colour-Magnitude Slope uncertainty in segments (double, Misc[see description])
This array is filled with the uncertainties associated with the slopes given by the fitting procedure
segments_correlation_coefficient : Correlation coefficient in segments (double, Dimensionless[see description])
The Pearson correlation coefficient $r$ between BP-RP and G is computed in each segment. The higher is the Pearson coefficient the higher is the probability that the stellar variability is due to rotational modulation. This array is filled with the Pearson coefficients obtained in the different segments
segments_correlation_significance : Correlation coefficient significance in segments (double, Dimensionless[see description])
this array is filled with the statistical significances associated with the Pearson coefficients computed in the different segments. The significance p associated with a given $r=r_{0}$ gives the probability $P(r\geq r_{0}$) that two sets of uncorrelated measurements have a Pearson coefficient $\geq r_{0}$
num_outliers : Number of outliers (int, Dimensionless[see description])
the number of outliers detected by the robust linear regression procedure
outliers_time : Times at which outliers occurs (double, Time[Barycentric JD in TCB - 2455197.5 (day)])
times at which the detected outliers occurred
segments_rotation_period : Rotation period in segment (double, Time[day])
A period search algorithm is applied to the different time-series segments. If the star is a solar-like variable the detected period is a measure of the stellar rotation period. This array is filled with the periods detected in the different segments (for each segment the period with the highest statistical significance is stored).
segments_rotation_period_error : Rotation period uncertainty in segment (double, Time[day])
This array is filled with the errors associated with the periods found in the different segments
segments_rotation_period_fap : FAP on rotation period in segment (double, Dimensionless[percentage/100])
False Alarm Probability = Probability that that a white noise sequence produces a peak similar or higher than the computed one; i.e., small FAP = little probability of noise, high FAP = noise is an acceptable explanation for the peak.
segments_cos_term : Coefficient of cosine term of linear fit in segment (double, Magnitude[mag])
if a significative period $T_{0}$ is detected in a time-series segment, then the points of the time-series segment are fitted with the function
$mag(t)=mag_{0}+Acos(\frac{2\pi}{T_{0}}t)+Bsin(\frac{2*\pi}{T_{0}}t)$ (14.1)
This array stores the A terms obtained by the fitting procedure in the different segments.
segments_cos_term_error : Errors on cosin terms (double, Magnitude[mag])
This array is filled with the errors associated with the A terms obtained from the fitting procedure in the different segments
segments_sin_term : Coefficient of sin term of linear fit in segment (double, Magnitude[mag])
if a significative period $T_{0}$ is detected in a time-series segment, then the points of the time-series segment are fitted with the function
$mag(t)=mag_{0}+Acos(\frac{2\pi}{T_{0}}t)+Bsin(\frac{2*\pi}{T_{0}}t)$ (14.2)
This array stores the B terms obtained by the fitting procedure in the different segments.
segments_sin_term_error : Errors on sine terms (double, Magnitude[mag])
This array is filled with the errors associated with the B terms obtained from the fitting procedure in the different segments
segments_a0_term : Constant term (A0) of linear fit in segment (double, Magnitude[mag])
if a significative period $T_{0}$ is detected in a time-series segment, then the points of the time-series segment are fitted with the function
$mag(t)=A_{0}+Acos(\frac{2\pi}{T_{0}}t)+Bsin(\frac{2*\pi}{T_{0}}t)$ (14.3)
This array stores the $A_{0}$ terms obtained by the fitting procedure in the different segments.
segments_a0_term_error : Errors on constant terms (double, Magnitude[mag])
This array is filled with the errors associated with the $A_{0}$ terms obtained from the fitting procedure in the different segments
best_rotation_period : Best rotation period (double, Time[day])
this field is an estimate of the stellar rotation period and is obtained by averaging the periods obtained in the different segments
best_rotation_period_error : Error on best rotation period (double, Time[day])
error on the best rotation period
segments_activity_index : Activity Index in segment (double, Magnitude[mag])
this array stores the activity indexes measured in the different segments. In a given segment the amplitude of variability A is taken as an index of the magnetic activity level. The amplitude of variability is measured by means of the equation:
$A=mag_{95}-mag_{5}$ (14.4)
where $mag_{95}$ and $mag_{5}$ are the 95-th and the 5-th percentiles of the $G$-band magnitude values.
segments_activity_index_error : error on Activity index in segment (double, Magnitude[mag])
this array stores the errors associated with the activity indexes in the $G$ band. In a given segment the error on the activity index A is computed by means of the equation:
$\sigma_{A}=\sqrt{\sigma_{mag95}^{2}+\sigma_{mag5}^{2}}$ (14.5)
where $\sigma_{mag95}$ and $\sigma_{mag5}$ are the uncertainties of the measurements associated with the 95th and 5th percentiles of the $G$-band magnitude values, respectively
max_activity_index : The maximum Activity Index (double, Magnitude[mag])
this field is the maximum of measured the activity indexes in the $G$ band
max_activity_index_error : Error on maximum activity index (double, Magnitude[mag])
this field stores the error associated with the maximum activity index in the $G$ band
segments_g_unspotted : The unspotted G mags in segment (double, Magnitude[mag])
in a given segment the G magnitude corresponding to the unspotted state is estimated by taking the minimum G value in the segment
segments_g_unspotted_error : The unspotted G mag uncertainties in segment (double, Magnitude[mag])
this array stores the errors associated to the unspotted G values registered in the different segments
segments_bp_unspotted : The unspotted BP mag in segment (double, Magnitude[mag])
in a given segment the BP magnitude corresponding to the unspotted state is estimated by taking the BP magnitude occurring at the same time of the unspotted G
segments_bp_unspotted_error : The unspotted BP mag uncertainties in segment (double, Magnitude[mag])
this array stores the errors associated to the unspotted BP values registered in the different segments
segments_rp_unspotted : The unspotted RP mag in segment (double, Magnitude[mag])
in a given segment the RP magnitude corresponding to the unspotted state is estimated by taking the RP magnitude occurring at the same time of the unspotted G
segments_rp_unspotted_error : The unspotted RP mag uncertainties in segment (double, Magnitude[mag])
this array stores the errors associated to the unspotted RP values registered in the different segments
g_unspotted : Unspotted G mag (double, Magnitude[mag])
final estimate of the G magnitude corresponding to the unspotted state. It is computed by taking the minimum G magnitude in the whole time-series
g_unspotted_error : Unspotted G mag uncertainty (double, Magnitude[mag])
this field stores the photometric error associated with g_unspotted
bp_unspotted : Unspotted BP mag (double, Magnitude[mag])
final estimate of the BP magnitude corresponding to the unspotted state. It is estimated by taking the BP magnitude occurring at the same time in which the minim G magnitude has been measured.
bp_unspotted_error : Unspotted BP mag uncertainty (double, Magnitude[mag])
error associated with the bp_unspotted value
rp_unspotted : Unspotted RP mag (double, Magnitude[mag])
final estimate of the RP magnitude corresponding to the unspotted state. It is estimated by taking the RP magnitude occurring at the same time in which the minim G magnitude has been measured.
rp_unspotted_error : Unspotted RP mag uncertainty (double, Magnitude[mag])
error associated with the rp_unspotted value
| 2019-05-22T07:40:43 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 23, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5671524405479431, "perplexity": 2809.6641158721227}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232256764.75/warc/CC-MAIN-20190522063112-20190522085112-00518.warc.gz"}
|
https://pos.sissa.it/358/205/
|
Volume 358 - 36th International Cosmic Ray Conference (ICRC2019) - CRI - Cosmic Ray Indirect
Towards an improved mass composition analysis with LOFAR
S. Buitink
Full text: pdf
Pre-published on: 2019 July 22
Published on:
Abstract
The LOFAR radio telescope measures air showers in the energy range $10^{17}$ to $10^{18}$ eV. For each measured shower, the depth of shower maximum Xmax is reconstructed by simulating the radio signal for an ensemble of showers using Corsika and CoREAS. Fitting their radio ‘footprints’ on the ground to the measured radio data yields an Xmax estimate to a precision of about 20 g/cm$^2$. Compared to previous works, we have improved the method in several ways. Local atmospheric data and refractive index profiles are now included into the simulations. The energy estimate and the fitting procedure are now done using the radio signals only, thus limiting systematic uncertainties due to the particle detector array (LORA). Using selection criteria from a more elaborate characterisation of the radio and particle detection, we reduce a composition bias in the Xmax reconstruction. A possible residual bias has been bounded from above. Thus, the systematic uncertainties on <Xmax> have been lowered, reducing an important limiting factor for composition studies at any level of statistics.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2019-10-19T00:41:05 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5254669785499573, "perplexity": 2100.5206014808373}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986685915.43/warc/CC-MAIN-20191018231153-20191019014653-00216.warc.gz"}
|
https://raymiller5050.com/baby-background-regenlr/83e51f-multivariate-analysis-in-r
|
# multivariate analysis in r
We will explain below how to standardise the variables. Therefore, to plot A basic understanding of ggplot2 is required. Again, we recommend making a .Rmd file in Rstudio for your own documentation. The second discriminant function (y-axis) achieves a fairly good separation of cultivars For example, in the wine data set, we have 13 chemical concentrations describing wine samples from three cultivars. For example, to calculate correlation coefficients between the concentrations of the 13 chemicals R package to do this. ac. The columns are separated by commas. variables corresponding to the concentrations of the first five chemicals. chemical’s concentration), we can use the function “calcWithinGroupsVariance()” below: You will need to copy and paste this function into R before you can use it. available on the “Kickstarting R” website, Since $$U$$ is orthonormal, $$U'U = I$$ is the identity. http://archive.ics.uci.edu/ml, for making data sets available just the cultivar 2 samples: You can calculate the mean and standard deviation of the 13 chemicals’ concentrations for just cultivar 1 samples, Applied Multivariate Analysis (MVA) with R is a practical, conceptual and applied “hands-on” course that teaches students how to perform various specific MVA tasks using real data sets and R software. We can check that each of the standardised variables stored in “standardisedconcentrations” We can do similar calculations for $$XX'$$. So the next step is to try to decide if there are more than two dimensions. Let $$X$$ be a centered but unscaled matrix. Description Applied Multivariate Analysis (MVA) with R is a practical, conceptual and applied "hands-on" course that teaches students how to perform various specific MVA tasks using real data sets and R … Learn to interpret output from multivariate projections. # get the mean and standard deviation for each group: # get the standard deviation for group i: # get the mean and standard deviation for group i: # calculate the separation for each variable, "variable V2 Vw= 0.262052469153907 Vb= 35.3974249602692 separation= 135.0776242428", "variable V3 Vw= 0.887546796746581 Vb= 32.7890184869213 separation= 36.9434249631837", "variable V4 Vw= 0.0660721013425184 Vb= 0.879611357248741 separation= 13.312901199991", "variable V5 Vw= 8.00681118121156 Vb= 286.41674636309 separation= 35.7716374073093", "variable V6 Vw= 180.65777316441 Vb= 2245.50102788939 separation= 12.4295843381499", "variable V7 Vw= 0.191270475224227 Vb= 17.9283572942847 separation= 93.7330096203673", "variable V8 Vw= 0.274707514337437 Vb= 64.2611950235641 separation= 233.925872681549", "variable V9 Vw= 0.0119117022132797 Vb= 0.328470157461624 separation= 27.5754171469659", "variable V10 Vw= 0.246172943795542 Vb= 7.45199550777775 separation= 30.2713831702276", "variable V11 Vw= 2.28492308133354 Vb= 275.708000822304 separation= 120.664018441003", "variable V12 Vw= 0.0244876469432414 Vb= 2.48100991493829 separation= 101.3167953903", "variable V13 Vw= 0.160778729560982 Vb= 30.5435083544253 separation= 189.972320578889", "variable V14 Vw= 29707.6818705169 Vb= 6176832.32228483 separation= 207.920373902178". To use this function, you first need to copy and paste it into R. The arguments to the I am grateful to the UCI Machine Learning Repository, Linear discriminant analysis is also known as “canonical discriminant analysis”, or simply “discriminant analysis”. The mid-way point between the mean values for cultivars 1 and 2 is (-3.42248851-0.07972623)/2=-1.751107, I. Olkin, A.R. each column in a dataframe “mydataframe”. analysis” (product code M249/03) by the Open University, available from the Open University Shop. quite a lot higher than that for the other variables. To get a more accurate idea of how well the first discriminant function Note that the square of the loadings sum to 1, as above: The second principal component has highest loadings for V11 (0.530), V2 (0.484), V14 (0.365), V4 (0.316), For example, we found above that the concentrations of the 13 chemicals in the wine samples show a wide range of Comparison of classical multidimensional scaling (cmdscale) and pca. analysis of the 13 chemical concentrations in wine samples, we type: This means that the first principal component is a linear combination of the variables: Multivariate analysis (MVA) is based on the principles of multivariate statistics, which involves observation and analysis of more than one statistical outcome variable at a time.Typically, MVA is used to address the situations where multiple measurements are made on each experimental unit and the relations among these measurements and their structures are important. We don't want the result of our PCA to change based on the units a dimension is measured in. As a multivariate procedure, it is used when there are two or more dependent variables, and is typically followed by significance tests involving individual dependent variables seperately. A Little Book of Python for Multivariate Analysis by Yiannis Gatsoulis is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. + 0.039*Z10 + 0.530*Z11 - 0.279*Z12 - 0.164*Z13 + 0.365*Z14, where Z1, Z2, Z3...Z14 There is another nice (slightly more in-depth) tutorial to R there is a little overlap in their values. have very different variances, which is true in this case as the concentrations of the 13 chemicals have the concentrations of V11 and V2, and the concentration of V12. Density and random generation for the multivariate t distribution, using the Cholesky factor of either the precision matrix (i.e., inverse scale matrix) or the scale matrix. Multivariate analysis in the human services, J.R. Schuerman, Springer Libri. essentially equal to 0, and the standard deviations of the standardised variables are all equal to 1. are very high compared to the mean values of V9 (-0.577), V3 (-0.292) and V5 (-0.736). are also not very different from the mean value of V12 (-1.202). We use ggplot2 here to show what's going on. Sampson, in International Encyclopedia of the Social & Behavioral Sciences, 2001. In this case, Multivariate Analysis with R. Cluster analysis. we type: Thus, the within-groups variance for V2 is 0.2620525. that you want included in the plot. Above, we interpreted the first principal component as a contrast between the concentrations of V8, V7, V13, V10, V12, and V14, the first column of x contains the first discriminant function, the second column of x contains the second For instance, we may have biometric characteristics such as height, weight, age as well as clinical variables such as blood pressure, blood sugar, heart rate, and genetic data for, say, a thousand patients. data set. Here we see what is called a “size effect”. Therefore, the misclassification rate is 9/178, or 5.1%. V2) using the function the “col=red” option will plot the text in red. of cultivar 3. and the number of variables is 13 (13 chemicals’ concentrations; p = 13). The figure below uses the default plotting function in ade4. This contains a matrix with the principal components, where the first column in the matrix We can therefore calculate the separations achieved by the two linear discriminant functions for the wine data by using the machine-learning r high-dimensional-data multivariate-analysis Updated Jan 28, 2019; R; dasaptaerwin / CikapundungProject Star 0 Code Issues Pull requests An R project on Cikapundung watershed dataset. Read section 1, 2, and 2.1 of the Wikipedia article about eigendecomposition of a matrix. first discriminant function is (794.652200566216*100/1155.893=) 68.75%, and the percentage separation achieved by the The variable returned by the lda() function also has a named element “svd”, which contains the ratio of Example 1. \begin{pmatrix} Get it as soon as Wed, Nov 4. There is one row per wine sample. Some choices can be found in help(vegdist). This booklet tells you how to use the R statistical software to carry out some simple multivariate analyses, it make sense that the second principal component can separate cultivar 2 from cultivars 1 and 3? Again, we recommend making a .Rmd file in Rstudio for your own documentation. for each pair of variables, but you might be just interested in finding out what are the most highly which I have used in the examples in this booklet. If you have a lot of variables, you can use “cor.test()” to calculate the correlation coefficient mean and standard deviation for each of the variables in your multivariate data set. In particular, the fourth edition of the text introduces R code for performing all of the analyses, making it an even more excellent reference … Description. # set the correlations on the diagonal or lower triangle to zero. We found above that variables V8 and V11 have a negative between-groups covariance (-60.41) and a positive within-groups covariance (0.29). and the concentrations of V9, V3 and V5; and that principal component 1 can separate cultivar 1 from cultivar 3. to answer some questions. are much less than the mean value of V12 (0.432). Multivariate statistics is a subdivision of statistics encompassing the simultaneous observation and analysis of more than one outcome variable. Now it is time to delve into our first worked example of a meta-analytic SEM using R.We will begin by using the SEM-based approach for multivariate meta-analysis, which has not been covered before.In multivariate meta-analyses, each study contributes more than just one effect size at the same time. So we type: This tells us that the mean of variable V2 is 13.0006180, the mean of V3 is 2.3363483, and so on. available on the “Introduction to R” website, This gives us the following plot: We can see from the scatterplot of V4 versus V5 that the wines from cultivar 2 seem to have We can obtain a scatterplot of the best two discriminant functions, with the data points labelled by cultivar, by typing: From the scatterplot of the first two discriminant functions, we can see that the wines from the three A biologically meaningful analysis of multivariate variance patterns is much more challenging than the analysis of averages. We will show that there is a matrix $$X_r$$ whose principal component output (without rescaling the columns) is the same as the eigendecomposition of $$X'X$$. To save time later, we'll save a default plot and a screeplot making function. Multivariate analysis of variance (MANOVA) is a procedure for comparing multivariate sample means. 1155.89, rounded to two decimal places. Exploratory Multivariate Analysis By Example Using R, Second Edition by Francois Husson, Sebastien Le, Jérôme Pagès, 9781138196346, T&F/Crc Press, 2017, Hardcover. This is exactly the goal of PCA. was 233.9 for V8, which is quite a lot less than 794.7, the separation achieved by the first discriminant function. in the LDA section; to John Christie for suggesting a more compact form for my printMeanAndSdByGroup() function, you can use the function “calcSeparations()” below: For example, to calculate the separations for each of the 13 chemical concentrations, we type: Thus, the individual variable which gives the greatest separations between the groups (the wine cultivars) is Looking at the screeplot though, it is evident that this dimension is not very well defined since there is a small jump in variance explained from this direction to the direction with next most variance. \end{pmatrix} I. Olkin, A.R. This booklet assumes that the reader has some basic knowledge of multivariate analyses, and Multivariate analysis methods are used in the evaluation and collection of statistical data to clarify and explain relationships between different variables that are associated with this data. first principal component is that it represents a contrast between the concentrations of V8, V7, V13, V10, V12, and V14, explain 80.2% of the variance (while the first four components explain just 73.6%, so are not sufficient). Introduction; Data; Methods; References; Introduction. Furthermore, the “scale()” Maybe there's something more important going on with the full structure of the dataset. The loadings for V11, V2, V14, V4, V6 and V3 are positive, while the “cor.test()” function in R. For example, to calculate the correlation coefficient for the first V2, V3, ... V14 are the concentrations of the 14 chemicals found in the wine samples. or for just cultivar 3 samples, in a similar way. plot that scatterplot in more detail, with the data points labelled by their group (their cultivar in this case). This is more in line with what we're interested in. Multivariate analysis is that branch of statistics concerned with examination of several variables simultaneously. Here, we're looking at the case with lots of genes and seeing if we can pick out the important ones. lower values of V4 compared to the wines of cultivar 1. - 1.496*V9 + 0.134*V10 + 0.355*V11 - 0.818*V12 - 1.158*V13 - 0.003*V14, where In the OHMS questions, we ask you about the relationship between the SVD of $$X'X$$, the eigendecomposition of $$X'X$$, and the SVD of $$X$$. This function requires the discriminant function (eg. Thus, it would be a better idea to first standardise the variables so that they all have variance 1 and mean 0, very different variances (see above). uk. function is 794.7, and the separation achieved by the second (second best) discriminant function is 361.2. the original (unstandardised) variables. three principal components. The freshwater, freshwater creek, and ocean are all together. function are a vector containing the names of the varibles that you want to plot, and Several multivariate data analysis techniques became accessible to organizations — and later, to everyone with a personal computer. Full of real-world case studies and practical advice, Exploratory Multivariate Analysis by Example Using R, Second Edition focuses on four fundamental methods of multivariate exploratory data analysis that are most suitable for applications. By default (using dudi.pca), we center the data and then rescale it so each column has a Euclidean norm of 1. The purpose of principal component analysis is to find the best low-dimensional representation of the variation in a multivariate data set. One way to do this is with multidimensional scaling. out that sd() and mean() is deprecated; to Arnau Serra-Cayuela for pointing out a typo The loadings for V8, V7, V13, as a cutoff for statistical significance), so there is very weak evidence that that the correlation is non-zero. Advantages and Disadvantages of Multivariate Analysis For example, to standardise the concentrations of the 13 chemicals in the wine samples, we type: Note that we use the “as.data.frame()” function to convert the output of “scale()” into a The default plotting functions in ade4 are very limitted. The short version is that there is a unifying connection between many multivariate data analysis techniques. It is often of interest to investigate whether any of the variables in a multivariate data set are discussed above (see the discussion of percentage separation above). set may be an overestimate. Let's see what $$X$$ actually looks like. We can use the “scatterplotMatrix()” function from the “car” However, this is probably an underestimate of the misclassification rate, as the allocation rule was based on this data (this is If we want to separate the wines by cultivar, the wines come from three different cultivars, so the number of groups (G) is 3, Multivariate analysis (MVA) is a Statistical procedure for analysis of data involving more than one type of measurement or observation. This lab was put together by authors who have different preferences in this notation. components), where each of these new variables is a linear combination of all or some of the 13 chemical concentrations. To carry out a principal component analysis (PCA) on a multivariate data set, the first step is often to standardise Compare the mean values of this new variable between groups. Multivariate Regression is a supervised machine learning algorithm involving multiple data variables for analysis. Again, we recommend making a .Rmd file in Rstudio for your own documentation. If we calculated the misclassification rate for a separate “test set” consisting of data other than that and the variable containing the group of each sample. (for instructions on how to install an R package, see How to install an R package). are not very different from the mean value of V12 (0.458). Why is the default to center and to scale? The second component seems to break up “Analysis” on the one end versus “English” on the other. principal component analysis (PCA, see below) of the in R to plot some text beside every data point. The objective of scientific investigations to which multivariate methods most naturally lend themselves includes. presented here, I would highly recommend the Open University book As mentioned above, we can do this using the “predict()” function in R. For example, variables, by plotting the value of each of the variables for each of the samples. Principal Component Analysis (PCA) in R Studio; Linear Discriminant Analysis (LDA) in R Studio; Classification in R Studio. In order to decide how many principal components should be retained, The purpose of "Exploratory Multivariate Analysis by Example using R" is to provide the practitioner with a sound understanding of, and the tools to apply, an array of multivariate technique (including Principal Components, Correspondence Analysis, and Clustering). Multivariate Analysis in R Lab Goals. Once you have standardised your variables, you can carry out a principal component analysis using the “prcomp()” Furthermore, the second discriminant function also the “RColorBrewer” library. To achieve a very good separation of the three cultivars, it would be best to use both the first and second Therefore, the discriminant function seems to represent a contrast between the concentrations of have much lower values of the first principal component than wine samples of cultivar 3. Now we will calculate the unifrac distance, and do an MDS. in increments of 2, and a vector of length 4 with values variance to the within-groups variance: As mentioned above, the loadings for each discriminant function are calculated in such a way that Multivariate Analysis 79 Incorporating Nonmetric Data with Dummy Variables 86 Summary 88 • Questions 89 • Suggested Readings 89 References 90 Chapter 3 Factor Analysis 91 What Is Factor Analysis? have very different standard deviations - the standard deviation of V14 is 314.9074743, while the standard deviation Usage second discriminant function as well. for V8 here). © Copyright 2010, Avril Coghlan. This component gives us an idea of what the students were good at. Sorted by: Results 1 - 10 of 21. univariate analysis and the Cox proportional hazard model for multivariate analysis. The dataset deug contains data on 104 French students' scores in 9 subjects: Algebra, Analysis, Proba, Informatic, Economy, Option1, Option2, English, Sport. For the statistically inclined, you can read the paper Multivariate Data Analysis: The French Way. \]. Multivariate Regression is a supervised machine learning algorithm involving multiple data variables for analysis. 13 chemical concentration variables. original data, without being overly biased by those variables that show the most variance in the original data. it is necessary to use both of the first two discriminant functions. Or you can make it very fancy in ggplot2. The first thing that you will want to do to analyse your multivariate data will be to read Multivariate Time Series Analysis with R and Financial Applications. V8, V13 and V14, and the concentrations of V11 and V5. cbind () takes two vectors, or columns, and “binds” them together into two columns of data. \begin{pmatrix} sapply(mydataframe,sd) will calculate the standard deviation of same values as just calculated (68.75% and 31.25%): Therefore, the first discriminant function does achieve a good separation between the three groups (three cultivars), but the second The maximum number of useful discriminant Similarly, we can obtain the loadings for the second principal component by typing: This means that the second principal component is a linear combination of the variables: each pair of variables in your data set, in order of the correlation coefficient. are scaled so that their mean value is zero (see below). For example, to extract the loadings for 2013;1(1):92-107. doi: 10.2174/2213235X11301010092. Example 2. u_{n1} \\ FREE Shipping by Amazon. Interpretation of MANOVA. This lets you see separates cultivars 2 and 3 quite well, although again there is a little overlap in their values so groups with a high mean value of V8 tend to have a low mean value of V11, and vice versa. Say for example, that we just want to include the Performs Cox regression on right-censored data using a multiple covariates. Another type of plot that is useful is a “profile plot”, which shows the variation in each of the Example data sets are included and may be downloaded to run the exercises if desired. two chemicals’ concentrations, V2 and V3, we type: This tells us that the correlation coefficient is about 0.094, which is a very weak correlation. In correlation you rescale by dividing by the norm of each dimension. http://a-little-book-of-r-for-time-series.readthedocs.org/. -0.144*Z2 + 0.245*Z3 + 0.002*Z4 + 0.239*Z5 - 0.142*Z6 - 0.395*Z7 - 0.423*Z8 + 0.299*Z9 The loadings for the principal components are stored in a named element “rotation” of the variable For example, for the wine data we get the The loadings for V8, V13 and V14 are negative, while variance for a variable such as V2: Thus, the between-groups variance of V2 is 35.39742. One of the best introductory books on this topic is Multivariate Statistical Methods: A Primer, by Bryan Manly and Jorge A. Navarro Alberto, cited above. Performing multivariate multiple regression in R requires wrapping the multiple responses in the cbind () function. \times component separates samples of cultivar 2 from samples of cultivars 1 and 3. \vdots \\ the loadings for the first discriminant function, the second column contains the loadings In survivalAnalysis: High-Level Interface for Survival Analysis and Associated Plots. principal component than wine samples of cultivars 1 and 3. Read sections 1, 2, and 3 of the Wikipedia article about SVD. while the values for cultivar 3 are between 2 and 6, and so there is no overlap in values. Les informations fournies dans la section « Synopsis » peuvent faire référence à une autre édition de ce titre. There is not a low rank structure left after accounting for this effect, and plotting this in two dimenions tells us little more than plotting only in one dimension. In our case, $$N=15$$. V2, V14, V4, V6 and V3, and the concentration of V12; and that principal component 2 can separate cultivar 2 from cultivars 1 and 3. -0.313*Z10 + 0.089*Z11 - 0.297*Z12 - 0.376*Z13 - 0.287*Z14, where Z2, Z3, Z4...Z14 are This is equivalent to the first $$k$$ eigenvectors of the covariance matrix. V13 (189.97), V2 (135.08) and V11 (120.66). output from calcSeparations() above. wine samples, as if you did that, the first principal component would be dominated by the variables In this scenario, the three outcome variables are measured simultaneously, and you may expect some extent of correlation among the outcome variables (e.g., A … In this case, the cultivar of wine is stored in the column Hence, Therefore, it does make sense that principal component 1 is a contrast between the concentrations of V8, V7, V13, V10, V12, and V14, by the lda() function. are given to V8 (-0.871), V11 (0.537), V13 (-0.464), V14 (-0.464), and V5 (0.438). There is a book available in the “Use R!” series on using R for multivariate analyses, such as the wine samples from different cultivars, it is often of interest to calculate the within-groups You can read data into R using the read.table() function. Multivariate Analysis term is used to include all statistics for more than two variables which are simultaneously analyzed.. Multivariate analysis is based upon an underlying probability model known as the Multivariate Normal Distribution (MND). The output from calcSeparations() tells us that the separation achieved by the first (best) discriminant Multivariate Analysis term is used to include all statistics for more than two variables which are simultaneously analyzed. “wine” by typing: To make a matrix scatterplot of just these 13 variables using the scatterplotMatrix() function we type: In this matrix scatterplot, the diagonal cells show histograms of each of the variables, in this Choosing the right metric can provide useful insights while others do not. the within-group variance (Vw) for each group (wine cultivar here) is equal to 1, as we see in the cultivars are well separated in the scatterplot. For example, to make a profile plot of the concentrations of the first five chemicals in the wine samples Recall the difference between correlation and covariance. to calculate the value of the discriminant functions for the wine data, we type: The returned variable has a named element “x” which is a matrix containing the linear discriminant functions: As you can probably tell, it is very hard to visually discover a low dimensional space in higher dimensions, even when “high dimensions” only means 4! - 1.496*V9 + 0.134*V10 + 0.355*V11 - 0.818*V12 - 1.158*V13 - 0.003*V14. # get the covariance of variable 1 and variable 2 for each group: # calculate the between-groups covariance. In data with a small number of samples, this is often an important first step. The MTS package associated with the book is available from R … rule for the first discriminant function, we type: This can be displayed in a “confusion matrix”: There are 3+5+1=9 wine samples that are misclassified, out of (56+3+5+65+1+48=) 178 wine samples: prints out the mean and standard deviation of the variables for each group in your data set: To use the function “printMeanAndSdByGroup()”, you first need to copy and paste it into R. The The “sapply()” function can be used to apply some other function to each column It helps to answer: Kindle $28.99$ 28. The total variance is equal to the sum As a result, it is not a good idea to use the unstandardised chemical concentrations as the input for a variable made by “prcomp”: The total variance explained by the components is the sum of the variances of the components: In this case, we see that the total variance is 13, which is equal to the number of standardised variables (13 variables). that was returned by the “prcomp()” function, so we can compare those values to the ones that we A Multivariate regression is an extension of multiple regression with one dependent variable and multiple independent variables. 0.484*Z2 + 0.225*Z3 + 0.316*Z4 - 0.011*Z5 + 0.300*Z6 + 0.065*Z7 - 0.003*Z8 + 0.029*Z9 So if we let $$X_r = X*\sqrt{N}$$, then the pca output will be the first $$k$$ eigenvectors of $$(X*\sqrt{N})‘(X*\sqrt{N}) / N = X'X$$. and to then carry out the principal component analysis on the standardised data. 1 and 3, or cultivars 2 and 3. Patient 2 is near VDR. Distance metric is very important dimension ( which corresponds to an object proportionality and if violated, out! The middle ( close to the first three components should be retained and V3 are positive, while those V11., rounded to two decimal places with community ordination data frame,.. The data looks linear in all four dimensions and V3 are positive, while loading! Mean solving problems where more than two variables which are all zeros, then is this decomposition?... You have read a multivariate analysis by Avril Coghlan licensed under a Creative Commons Attribution 3.0 License ' X/N\.. Each observation we try to decide if there are more than two which! Techniques became accessible to organizations — and later, we try to predict the output triangle to.! Can find at most 2 useful discriminant functions to separate the wines by cultivar, using the (. = UDV'\ ) first component is obviously the most change in the human services, J.R. Schuerman, Libri. Covariance, we 'll save a default plot and a screeplot making.... So each column in a multivariate analysis term is used to apply the multivariate to! The second component seems to break up “ analysis ” on the “ sapply ( ) takes two vectors or. Data. value to an object each standardised variable is analyzed simultaneously other... Are scaled so that each dimension has variance 1 version of this variable..., 2001: High-Level Interface for Survival analysis and the Cox proportional hazard model for multivariate analysis data into ¶. To apply some other function to each column in a multivariate data set above, we recommend making.Rmd. Later, we cut the data. in to OHMS measured on the of! R “ MASS ” package looking at the case with lots of genes seeing... And shapes an important first step is stored in the screeplot ) apply to! Run the exercises if desired and therefore the accuracy of the package ade4 are the... And no columns which are all together that on the one end versus “ English ” the... Dans la section « Synopsis » peuvent faire référence à une autre édition de ce titre became accessible organizations... ) actually looks like ) and PCA the tutorial assumes familiarity both with R and Financial Applications covariance, get. Actually plotting the data and clean it some the centered ) \ ( =.: //web.stanford.edu/class/bios221/labs/multivariate/lab_5_multivariate.html multivariate analysis in the left are the bluest points and they seem to get darker linearly as move! Multivariate analysis ¶ multivariate analysis of variance could be used to test this hypothesis ) eigenvectors of the:! Do similar calculations for \ ( X = UDV'\ ) an object Series analysis with r. out. Are the bluest points and they seem to get darker linearly as you right. Group, find the mean values of the variable “ wine ” a technique for groups... Analysis data into R ¶ some functions in ade4 and 4 are near JUN ORAI2! Synopsis » peuvent faire référence à une autre édition de ce titre distinguishing wine of... Dudi.Pca ), we only plot the directions in which there is a subdivision of statistics with... Is equivalent to the freshwater creek, and weight in survivalAnalysis: High-Level Interface for Survival analysis and the proportional! To verify that our calculations are correct therefore the accuracy of the package.. V5 and V4 dimension ( which corresponds to a numerical analysis using functions from the aforementioned,... Choice of a distance metric is very important when working with data '! If violated, carry out a linear discriminant analysis ” on the “ introduction to,. Is also known as the multivariate Normal Distribution ( MND ) by a variable as between-groups! A matrix or 5.1 % always used when more than just the phylogenetic tree, we center data! By a variable as its between-groups variance devided by its within-groups variance tests are always used when more two... Include more information using ggplot to add colors and shapes provide useful insights while others do not the statistical! It corresponds to an object or high-dimensional data. the cultivar is stored in 2-14! Interface for Survival analysis and the Cox proportional hazard model for multivariate ¶... ( using dudi.pca ), ncol=4 ) analysis ¶ multivariate analysis of multivariate counts to... Function ( eg something more important going on with the full structure of the variables analyses will be data! Read sections 1, 2, and 3 function on the “ introduction to multivariate ¶. Of interest to investigate whether any of the Social & Behavioral Sciences, 2001 for! 20 ), we subtract the mean from each observation achetez multivariate analysis the... Tree, we subtract the mean from each observation those of cultivar 3 informations fournies dans la section « »! That our calculations are correct vegdist ) to test them nice ( more... Which is ( 794.652200566216+361.241041493455=1155.893 ) 1155.89, rounded to two decimal places how well the students good! What 's going on with the full structure of the variable “ wine ” a plot of package! R statistical software to carry out some simple... Reading multivariate analysis has either the units a dimension measured. Associated Plots 233.9 for V8, V13 and V14 are negative, while those for V11 and are. Regression on right-censored data using a multiple covariates hypotheses and do an MDS unscaled matrix technique for finding in... Do experiments to test them multivariate analysis in r a.Rmd file in Rstudio for your own documentation continuous-continuous. The other five chemicals expected before actually plotting the data. is annotated with more than three are. And with community ordination function on the singular value decomposition read a multivariate is... Are also stored in columns 2-6 of the scree plot that the.. Compare the mean from each observation techniques to multivariate analysis the other can! Components of \ ( U\ ) is a supervised machine learning algorithm multiple... Similar calculations for \ ( D = D'\ ) analysis for Business Analytics component has the largest variation and... 5.1 % correlations on the same set of subjects: patients, samples this. Hazard model for multivariate analysis data into R, a good online tutorial is available on the as... Apply this to the freshwater creek ) and later, we cut the data and a. This book is licensed under CC-BY-3.0 than the analysis of multivariate or data... Would retain the first \ ( k\ ) eigenvectors of the Social & Behavioral Sciences,.! ; data ; methods ; References ; introduction we 'll save a default plot and a screeplot function! Cation if we are able to pick out the minimum and maximum of! Functions to separate the wines by cultivar, using Kaiser ’ s criterion, we have 13 concentration! Component gives us an idea of what the students did to break up “ analysis ” these! Is very important dimension ( which corresponds to a numerical analysis using the “ introduction to R, misclassification... And categorical-categorical can pick out these interesting genes variables we want to include the:... You can use = and < - interchangeably in R Studio ; linear discriminant analysis PCA. Include the variables all the wine data set, we have collected groundwater quality data for several years based... Right-Censored data using a multiple covariates sections 1, Robert Powers 1 Affiliation 1 Department of Chemistry, of. V8 here ) course, data analysis with r. Check out the minimum maximum. First step ” website, cran.r-project.org/doc/contrib/Lemon-kickstart a fancy plot from ggplot2 ) takes two vectors, or simply discriminant. Or you can read data into R using the “ introduction to R ” website cran.r-project.org/doc/contrib/Lemon-kickstart. An assessment primarily of the dataset up “ analysis ” analysis ”, or organisms the full of! The bluest points and they seem to get darker linearly as you move right 1 Affiliation Department... In-Depth introduction to R ” website, cran.r-project.org/doc/manuals/R-intro.html analysis with r. Check out the course here https. 1 ( 1 ):92-107. doi: 10.2174/2213235X11301010092 genes and seeing if we can find at most 2 useful functions... I\ ) is the sum of these, which is ( 794.652200566216+361.241041493455=1155.893 ) 1155.89 rounded! Include more information using ggplot to add colors and shapes cound be argued based the... Have different preferences in this book is licensed under CC-BY-3.0 édition de ce.! The simultaneous observation and analysis of more than just the phylogenetic tree, we \!, patients 3 and 4 are near the middle ( close to the first principal component analysis PCA...: multivariate ” which pair of variables are most highly correlated a profile plot them together into two of! Have read a multivariate data analysis: machine learning algorithm involving multiple data variables for analysis data. Cran package ade4 very limitted: patients, samples, this is because for data. Is through cluster analysis, a good online tutorial is available on the “ introduction to R ” website cran.r-project.org/doc/contrib/Lemon-kickstart! ) function data using a multiple covariates columns, and we will look at an and! Class cation if we are able to pick out the important ones ( X\ ) actually looks like Euclidean. This is equivalent to the freshwater, freshwater creek ) basic or-dination methods, we would suggest that analysis. Standardised data, we multivariate analysis in r the data. packages, the separation achieved by norm... And the genes on the one end versus “ English ” on the same set of subjects patients. Variance for a particular variable ( 233.9 for V8, V13 and are!: this lab will focus on the singular value decomposition which are simultaneously analyzed under CC-BY-3.0 achievable by any variable...
| 2021-04-21T20:47:13 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5511199235916138, "perplexity": 1314.1188379081482}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618039550330.88/warc/CC-MAIN-20210421191857-20210421221857-00347.warc.gz"}
|
https://www.andywills.info/rminr/evidence.html
|
Before you start…
Before starting this exercise, you should have had a brief introduction to getting and using RStudio – Introduction to RStudio. You should also have also completed the workshop exercises for Exploring Data and Group Differences. If not, take a look these earlier worksheets before continuing.
First, log in to RStudio server, and make sure you are in your psyc411 project.
Next, create a new script file in your project, called evidence.R.
Now, you load tidyverse and you load the income data frame, and create the cpslow data frame by adding the following commands and comments to your R script, and using CTRL+ENTER to run each command in turn:
## EVIDENCE
library(tidyverse)
# Filter to incomes < $150K cpslow <- cpsdata %>% filter(income < 150000) What’s a p value? The first thing we’re going to go in this class is calculate a p value. In its most basic form, a p value is just a probability. A probability is a number between 0 and 1 that represents how likely something is to happen. For example, if you flip a fair coin, P(Heads) = 0.5, and P(Tails) = 0.5. If you roll a six-sided dice, the probability of rolling a 3 (or any other number) is 1/6. In psychology, when people talk about p values, they normally mean something a bit more specific. They mean the probability that we would have got the data we did, given a theory that we have. When psychologists talk about p values, that theory is nearly always a theory of no difference (a null hypothesis). For example, we might have the null hypothesis that men and women in the US have exactly the same mean income, and we collect some data to test this. For example, we have our cpsdata dataset, which is data on the incomes of 10,000 US men and women. When we started looking at this data (see the previous Group Differences workshop), we observed that the mean salary for women was several thousand dollars lower than the mean salary for men. Our sample of 10,000 people is less than 1% of the US population, and the effect size in our sample is small (the difference in means is about one-fifth of the standard deviation). Still, on the face of it, it seems unlikely that our data (our sample) would have a gender pay gap of several thousands dollars if, in the US as a whole (i.e. in the US population), male and female mean salaries were exactly the same. So, the probability of our data, given the null hypothesis, seems like it should be quite low. R allows us to estimate how low this probability is, under the assumption that we have a random sample of the population. One way to do this is to use a between-subjects t-test. Between-subjects t-test We are aiming to calculate the probability of the income data we have collected, under the theory that men and women have identical mean incomes. One way we can do that is to perform a t-test. A t-test takes two things into account when calculating this probability: 1. the effect size, see Group Differences 2. the sample size (i.e. the number of people in our sample, in this case 10,000). If we hope to find a low probability despite a low effect size, we will need a large sample. Although our effect size is small (about 0.2, see Group Differences), our sample is quite large (10,000 people). In R, the command for a t-test is very similar to the command for calculating effect size (see Group Differences). In fact, all we need to do is replace cohen.d with t.test. So, the comment and command to add to your script and run is: # Perform t-test on income, by sex t.test(cpsdata$income ~ cpsdata$sex) Welch Two Sample t-test data: cpsdata$income by cpsdata$sex t = -3.6654, df = 9991.3, p-value = 0.0002482 alternative hypothesis: true difference in means between group female and group male is not equal to 0 95 percent confidence interval: -14518.10 -4400.64 sample estimates: mean in group female mean in group male 82677.29 92136.66 The key figure in the output is the p-value. We can see here that the p value is, as we expected, very low, it’s about .0002. So, given a theory that male and female mean incomes are identical in the US population (our null hypothesis), the probability of observing the data we did (our sample), is very low (less than 1 in 1000). Note: Technically, it’s the probability of observing at least the difference in means that we did (i.e. a difference in means equal or larger than the one we observed), under the assumption the null hypothesis is correct. Reporting a t-test Psychologists will generally record this probability in their articles. So, in this case, they would writep = .0002 or, alternatively, p < .05. The latter form, p < .05, reads “the p value is less than .05”. More on this later. Psychologists usually also report at least two further numbers when reporting a t-test in their articles. The first is the t value, t. Our t value in this case is about 3.67 (we can safely ignore the minus sign). The second is the “degrees of freedom” (df). Degrees of freedom are a way of talking about the size of the dataset used in the t test. You’ll see it isn’t quite the sample size, because we know our sample size was 10,000, yet the df are a bit lower than that: 9991.3. In summary, t = 3.67, df = 9991.3, and p = .0002. Psychologists have a standard shorthand for this, which is to write, t(9991.3) = 3.67, p = .0002. You’ll see this sort of thing in most psychology articles. In more recent articles, you’ll also see a report of the effect size, in this case d = .020, as we calculated previously. The whole sentence would be something like: Men earned more than women, d = .20, t(9991.3) = 3.67, p < .05. There’s quite a bit of other output from our t-test that we haven’t discussed. If you’re curious about what the rest of the output means, take at look at more on t-tests. In particular, there is a section on confidence intervals, which may come up in some of your other teaching. Interpreting a t-test As we covered above, psychologists often report any p value less than .05 as simply p < .05. This comparison to .05 (1 in 20) is an arbitrary convention in our subject. The convention, in practice, works as follows: • If p < .05 then psychologists will believe your observed difference is real and allow you to proclaim it as “statistically significant”, and to publish it. • If p >= .05 then psychologists will be sceptical. They probably won’t believe your observed difference is real, and they’ll expect you to describe it as “statistically non-significant”. Sometimes, if p is between .05 and about 0.15, authors will describe their finding as “marginally significant”. Psychologists will also tell you (quite accurately) that a “non significant” p value gives you no more information than you had before you collected the data. So, a non-significant p-value does not mean you have evidence for the null. Instead, you have an absence of evidence. This seems crazy – after all, you now have some data, surely that tells you something? This is a big problem with p values, but it is not the only one, as we’ll see in a moment. Psychologists misinterpret p values The p value is P(data | null) – which means the probability of our data, assuming the null hypothesis is correct. The traditional way of interpreting this p value (see above) treats it is as if it were the: P(null | data) – the probability of the null hypothesis, given the data. These two things are not the same, but psychologists have a long history of not realising this. So, if you can’t see what the problem is just yet, you’re in good company! Below, I’ll try and illustrate the error with an analogy. If you understand the analogy, you understand (at some level) what the problem is. If you don’t get it, don’t worry too much – in the next section, we’ll look at a different sort of test that allows us to avoid the error. Your car won’t start? There must be a banana in the exhaust pipe! To make this all a bit less abstract, let’s make the data “your car doesn’t start”, and my theory “there’s a banana in your exhaust pipe”. Sticking a banana up your car’s exhaust pipe (not recommended!!) is a reasonably effective way of making it so your car won’t start. So the probability your car won’t start, given there’s a banana in the exhaust pipe, is quite high. Let’s say that P(nostart | banana) = 0.95. However, the probability your car has a banana in its exhaust pipe, given the fact it doesn’t start, is quite low. There are lots of reasons a car might not start (flat battery, no fuel, …), so the probability that my theory (that there’s a banana in your exhaust) is correct, given the data that your car does not start, is quite low. You’d be better off checking the battery and the fuel gauge first. You can save searching for fruit in your exhaust pipe for later. Let’s say P(banana | nostart ) = .01. In summary, P(nostart | banana) = 0.95, but P(banana | nostart) = .01. The only thing to take from this example is that these two numbers are not the same. Similarly, P(data|null) will seldom be the same as P(null|data). How likely is the null hypothesis? It is possible to calculate what we want to know, P(null|data), given what a t-test gives us, P(data|null), but we have to know P(null) – the probability the null hypothesis was correct before we collected our data. We normally don’t know this precisely but we can make an informed guess. For example, say you have the hypothesis that if people read a few sentences related to old age, they will walk more slowly. Believe it or not, this is a real example of a psychological hypothesis. Before collecting any data, this hypothesis seems unlikely. If the experiment is well designed, we might conclude that the probability of the null hypothesis was rather high. Let’s say, P(null) = 0.95. We run the experiment, do a t-test, and get a p value of .049. So, P(data|null) = .049. Traditionally, psychologists would call this a significant result, believe you, and allow you to publish it. This is the wrong response because, in this case, P(null|data) is about 0.5 (not .05, .5! 50:50 !) . In other words, instead of running the experiment, you’d have done just as well to flip a coin and say your hypothesis was right if the coin came up heads. This is no way to run a research programme, and probably goes some way to explain why psychology is full of reports of weird findings that aren’t real (aka. the “replication crisis”“). Bayes Factors We can escape this whole confusing mess of the traditional t-test by calculating a Bayes Factor rather than a p value. A Bayes Factor is a number that tells us how likely it is there’s a difference between groups For example, a Bayes Factor of 10 means it’s ten times more likely there is a difference than there isn’t. A Bayes Factor less than 1 is also informative. For example, a Bayes Factor of 0.1 (1/10) tells you it’s ten times more likely that there isn’t a difference than there is. A Bayes Factor of exactly 1 tells you that the presence or absence of a difference is equally likely. All the above assumes that, before you collected the data, you thought the presence or absence of a difference were equally likely outcomes. If that is not the case, see more on Bayes Factors. Between-subjects Bayesian t-test A Bayesian t-test is used for the same sorts of things as a traditional t-test (see above), but returns a Bayes Factor rather than a p value. The easiest way to do a Bayesian t-test in R is to use the BayesFactor package. Recall, that you load a package using the library command. So, the next comment and command to add to your script and run is: # Load package for Bayes Factors library(BayesFactor) R will return a welcome message and various other text in response to this command (we do not show this text here, as it is quite long). You can safely ignore that text. However, if you get an error here, please see common errors. The command for a Bayesian t-test is similar, but not identical, to the commands for effect size and for a traditional t-test. For our gender pay gap example, we add the following command to our script and run it: # Perform Bayesian t-test on income, by sex ttestBF(formula = income ~ sex, data = data.frame(cpsdata)) Bayes factor analysis -------------- [1] Alt., r=0.707 : 18.25138 ±0% Against denominator: Null, mu1-mu2 = 0 --- Bayes factor type: BFindepSample, JZS The Bayes Factor is reported on the third line, towards the right. Our Bayes Factor is about 18.25. This means it’s about 18 times more likely that there is a gender pay gap in the US population than that there isn’t. If you’re curious about what the rest of the output means, see more on Bayes Factors. Explanation of command The ttestBF() (short for “Bayes Factor t-test”) command has two components, separated by a comma: 1. formula = - Here we tell R what we want to analyse (the income column of our data frame), and which group each income belongs to (which is found in the sex column). The tilde, ~ is used in the same way as in the effect size calculation and the standard t-test, i.e. it means “as a function of”. So income ~ sex means look at income as a function of biological sex. Unlike cohen.d, we don’t need to say cpsdata$income because of the second component of the command:
2. data = - Here we tell R which data frame to use; in our case cpsdata. Due to a limitation of the BayesFactor package, we have to specifically tell it to treat our data as a data frame (hence data.frame(cpsdata) rather than just cpsdata).
Reporting a Bayes Factor
Psychologists love a “line in the sand”, so a convention has emerged that we believe there is a difference if the Bayes Factor is greater than 3, and believe there isn’t a difference if the Bayes Factor is less than 0.33. We sometimes describe these lines in the sand as “substantial evidence for a difference” (BF > 3) and “substantial evidence for the null” (BF < 0.33). In good, recent papers, you will see a Bayes Factor reported alongside the effect size and results of a traditional t-test. The full sentence might be something like:
Men earned more than women, d = .20, BF = 18.25, t(9991.3) = 3.67, p < .05.
Others, like Kass & Raftery (1993), have provided some additional guidelines on how to interpret Bayes Factors. It is a more detailed guide than a simple “line in a sand” and can prove very useful when comparing multiple studies. The following comes from Andraszewicz et al. (2014):
Bayes Factors Interpretation A rule-of-thumb interpretation of Bayes Factors > 100 Extreme evidence for the alternative hypothesis 30 - 100 Very strong evidence for the alternative hypothesis 10 - 30 Strong evidence for the alternative hypothesis 3 - 10 Moderate evidence for the alternative hypothesis 1 - 3 Anecdotal evidence for the alternative hypothesis 0.33 - 1 Anecdotal evidence for the null hypothesis 0.10 – 0.33 Moderate evidence for the null hypothesis 0.03 – 0.10 Strong evidence for the null hypothesis 0.01 – 0.03 Very strong evidence for the null hypothesis < 0.01 Extreme evidence for the null hypothesis Note that this is BF10, which means that the larger the Bayes Factor is, the more evidence we have for the alternative hypothesis.
Sometimes, you’ll see Bayes Factor written as BF10, which means the same thing as BF. You’ll also occasionally see BF01, which is the same idea but flipped, so BF01 < 1/3 means substantial evidence for a difference, and BF01 > 3 means substantial evidence for the null.
Which Bayesian t-test?
In order to calculate a Bayes Factor, R has to make some assumptions about how big the difference is likely to be. The ttestBF command does this for you, making some broad assumptions that cover the range of effect sizes typically seen in psychology. Other commands may make different assumptions, including estimating the likely effect size from previous experiments. So, when reporting Bayes Factors, it’s particularly important to report, somewhere in your Results section, the specific method that you used. For the ttestBF function you’d write something like:
“Bayesian t-tests were calculated using the BayesFactor package (Morey & Rouder, 2022), within the R environment (R Core Team, 2022).”
You can get the references for these citations by typing citation("BayesFactor") and citation().
Exercise
In this exercise, you’ll consolidate what you’ve learned so far.
The task is to further examine this sample of participants who are living in the US (cpsdata) , and earning less than $150k (cpslow). # EXERCISE Specifically, the task is to perform a traditional t-test and a Bayesian t-test to address the question of whether people born in the US earn more. So, after adding the comment above, add commands to the end of your script to do this, and run them. Your output should look like the below if you’ve got it right. As you can see, the Bayesian evidence for a difference is pretty overwhelming in this case – it’s about 3.5 million times more likely there is a difference than there isn’t! Expected output Welch Two Sample t-test data: cpslow$income by cpslow\$native
t = -6.5669, df = 1473.8, p-value = 7.102e-11
alternative hypothesis: true difference in means between group foreign and group native is not equal to 0
95 percent confidence interval:
-9716.752 -5246.980
sample estimates:
mean in group foreign mean in group native
51422.69 58904.56
Bayes factor analysis
--------------
[1] Alt., r=0.707 : 3534729 ±0%
Against denominator:
Null, mu1-mu2 = 0
---
Bayes factor type: BFindepSample, JZS
Note: 7.102e-11, what does that mean? It’s scientific notation (a.k.a. “Standard Form”), so is read 7.102 x 10-11. You would have been taught scientific notation in school, but here’s a reminder if you need it BBC bitesize revision guide on standard form.
Now write a single sentence that reports what you’ve found in the standard way. It will be of the form:
Immigrants earn less than those born in the US, BF = , t( ) = , p = (or you could replace p= with p <).
Fill in the blanks!
When p-values and Bayes Factors disagree
Question: So, what if your p-value is less than .05, but your Bayes Factor is less than 3?
Answer: Believe the Bayes Factor, and ignore the p value. The p value is there for historical reasons and doesn’t tell you anything you actually want to know. If you’d like to read more about this issue, take a look at more on Bayes Factors.
This material is distributed under a Creative Commons licence. CC-BY-SA 4.0.
| 2022-12-03T14:47:49 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5501424074172974, "perplexity": 1434.7588897582903}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710933.89/warc/CC-MAIN-20221203143925-20221203173925-00314.warc.gz"}
|
https://www.usgs.gov/publications/progress-toward-establishing-national-assessment-water-availability-and-use
|
# Progress toward establishing a national assessment of water availability and use
March 15, 2013
The Omnibus Public Land Management Act of 2009 (Public Law 111-11) was passed into law on March 30, 2009. Subtitle F, also known as the SECURE Water Act, calls for the establishment of a "national water availability and use assessment program" within the U.S. Geological Survey (USGS). A major driver for this recommendation was that national water availability and use have not been comprehensively assessed since 1978. This report fulfills a requirement to report to Congress on progress in implementing the national water availability and use assessment program, also referred to as the National Water Census. The SECURE Water Act authorized \$20 million for each of fiscal years (FY) 2009 through 2023 for assessment of national water availability and use. The first appropriation for this effort was \$4 million in FY 2011, followed by an appropriation of \\$6 million in FY 2012. The National Water Census synthesizes and reports information at the regional and national scales, with an emphasis on compiling and reporting the information in a way that is useful to states and others responsible for water management and natural-resource issues. The USGS works with Federal and non-Federal agencies, universities, and other organizations to ensure that the information can be aggregated with other types of water-availability and socioeconomic information, such as data on food and energy production. To maximize the utility of the information, the USGS coordinates the design and development of the effort through the Federal Advisory Committee on Water Information. A National Water Census is a complex undertaking, particularly because there are major gaps in the information needed to conduct such an assessment. To maximize progress, the USGS engaged stakeholders in a discussion of priorities and leveraged existing studies and program activities to enhance efforts toward the development of a National Water Census.
## Citation Information
Publication Year 2013 Progress toward establishing a national assessment of water availability and use 10.3133/cir1384 William M. Alley, Eric J. Evenson, Nancy L. Barber, Breton W. Bruce, Kevin F. Dennehy, Mary Freeman, Ward O. Freeman, Jeffrey M. Fischer, William B. Hughes, Jonathan Kennen, Julie E. Kiang, Kelly O. Maloney, MaryLynn Musgrove, Barbara E. Ralston, Steven Tessler, James P. Verdin Report USGS Numbered Series Circular 1384 cir1384 USGS Publications Warehouse Earth Resources Observation and Science (EROS) Center
| 2022-06-29T10:17:55 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4312334656715393, "perplexity": 7331.971640799994}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103626162.35/warc/CC-MAIN-20220629084939-20220629114939-00329.warc.gz"}
|
http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S2007-09342018000200417&lng=es&nrm=iso&tlng=en
|
Articulo
• Similares en SciELO
versión impresa ISSN 2007-0934
Rev. Mex. Cienc. Agríc vol.9 no.2 Texcoco feb./mar. 2018
https://doi.org/10.29312/remexca.v9i2.1082
Articles
Evaluation of the production cost of neotropical ectomycorrhizal inoculants based on spores
1División de Ciencias Forestales-Universidad Autónoma Chapingo. Carretera México-Texcoco km 38.5, Chapingo, Estado de México. CP. 56230. Tel. 01(595) 9521500, ext. 5468. ([email protected]; [email protected]; [email protected]).
2Microbiología, Edafología-Campus Montecillo, Colegio de Postgraduados. Carretera México-Texcoco km 36.5, Montecillo, Texcoco, Estado de México, CP. 56230. Tel. 01(595) 9520200, ext. 1280. ([email protected]).
3Tecnológico de Estudios Superiores del Oriente del Estado de México. Paraje San Isidro s/n, Barrio de Tecamachalco, La Paz, Estado de México, México. CP. 56400, Tel. 5559863497. ([email protected]).
Abstract
The biological diversity in any ecosystem is fundamental for its existence and balance. Logging undoubtedly alters this diversity. An example is the modifications in the communities of ectomycorrhizal fungi, which are fundamental for the species of forest importance. Due to the above, it is essential for reforestation to carry out mycorrhization in the nursery and thereby favor the establishment of trees in the field, especially in highly disturbed or eroded areas. However, reintroducing ectomycorrhizal species is a challenge due to the ecological, biotechnological and financial implications. Particularly, there is scarce information that analyzes the production cost of ectomycorrhizal inoculants based on spores and the species or the criteria to choose the ectomycorrhizal fungus species suitable for preparation of inoculants. In the present work, the cost of production of Neotropical inoculants based on spores of edible ectomycorrhizal fungi species native to Mexico belonging to Laccaria spp. and Hebeloma spp. The production costs of the spore-based ectomycorrhizal inoculant evaluated in the present work were $2.00 Mexican pesos per gram for the powder inoculum and$0.05 pesos per mL for the liquid inoculum. Both inoculants are effective in the pine mycorrhizal colonization. We demonstrate the financial feasibility of the production of ectomycorrhizal inoculants to inoculate pine trees of forest importance.
Keywords: Hebeloma spp.; Laccaria spp. and Suillus spp
Resumen
La diversidad biológica en cualquier ecosistema es fundamental para su existencia y equilibrio. La explotación forestal altera indudablemente esta diversidad. Un ejemplo son las modificaciones en las comunidades de hongos ectomicorrízicos, los cuales son fundamentales para las especies de importancia forestal. Debido a lo anterior es imprescindible para la reforestación llevar a cabo la micorrización en vivero y con ello favorecer el establecimiento de los árboles en campo sobre todo en áreas altamente perturbadas o erosionadas. Sin embargo, el reintroducir a las especies ectomicorrízicas es todo un reto por las implicaciones ecológicas, biotecnológicas y financieras. Particularmente, existe escasa información que analice el costo de producción de inoculantes ectomicorrízicos a base de esporas y de las especies o los criterios para elegir la especie de hongo ectomicorrízico adecuado para preparación de inoculantes. En el presente trabajo se realizó la evaluación del costo de producción de inoculantes Neotropicales a base de esporas de especies de hongos ectomicorrízicos comestibles nativos de México pertenecientes a Laccaria spp. y Hebeloma spp. Los costos de producción del inoculante ectomicorrízico a base de esporas evaluado en el presente trabajo fueron de $2.00 por gramo para el inóculo en polvo y de$0.05 por mL para el inóculo líquido. Ambos inoculantes son efectivos en la colonización micorrízica de pinos, se demuestra la factibilidad financiera de la producción de inoculantes ectomicorrízicos para inocular pinos de importancia forestal.
Palabras claves: Hebeloma spp.; Laccaria spp. y Suillus spp
Introduction
In a forest, most plants naturally mycorrhize, since they find propagules in the soil for their mycorrhization, such as spores, sclerotia, mycelium, mycorrhizal roots and rhizomorphs. One of the most studied propagules has been the spores, which have a considerable longevity since they can remain in the soil for several years and even decades before germinating (Bruns et al., 2009; Nguyen et al., 2012). In the case of plant production in nursery, the plant is outside its natural habitat and is unable to access enough fungal propagules for its mycorrhization, so it is necessary to carry out the inoculation in the nursery.
Therefore, it is essential to know the techniques of production of inocula with ectomycorrhizal fungi and the costs involved. There are three inoculation techniques with ectomycorrhizal fungi in the nursery that are: inoculation with monte soil, inoculation based on spores and inoculation with vegetative mycelium (Landis et al., 1989; Rossi et al., 2007; Duponnois et al., 2011). In Mexico, most traditional nurseries use the forest floor as a substrate for plant production and take advantage of it as the sole source of ectomycorrhizal fungal propagules. However, this method has a set of deficiencies, which include: i) the possibility of introducing pathogens; ii) the lack of a mycorrhization controlled by the heterogeneity of distribution of the ectomycorrhizal propagules; and iii) the erosion and destruction of the forest areas from which the soil is extracted.
The second method is the inoculation based on spores that consists in the application of the ectomycorrhizal inoculant in the irrigation water or it can also be mixed in the substrate. For the preparation of said inoculant, the ectomycorrhizal fungus is dehydrated or ground fresh and applied to the substrate. It is important to select an ectomycorrhizal species that is in abundance for the preparation of said inoculant, since large quantities of fresh fungi are required due to their high moisture content. The third method of inoculation is by means of fungal mycelium, this is based on the selection, isolation, purification and subsequent propagation of the ectomycorrhizal fungus in a carrier for example in a mixture of peat-vermiculite; which is applied directly to the substrate that will be used in the nursery.
The fungal mycelium can also be included in sodium alginate, in order to avoid dehydration and keep it in good condition until its application; this technique of preparation of inoculants has also given very good results (Pera et al., 1998; Oliveira et al., 2006). Several factors must be taken into account for the selection of the species of ectomycorrhizal fungus to be used as an ectomycorrhizal inoculant based on spores or mycelium, such as: i) the compatibility of the fungus with the host plant; ii) the efficiency of the mycobiont to promote rapid mycorrhization, greater growth and survival of the plant; iii) the shelf life of the mycobiont; iv) quality control in the production process of inoculants; and v) the methodological and financial feasibility of production of the inoculants (Brundrett et al., 1996a).
In particular, this last aspect has received little attention, mainly in the production of neotropical ectomycorrhizal inoculants. In the present study, an analysis of the costs of inoculants based on powder and liquid spores is described and carried out. The efficiency of the analyzed inoculants was evaluated in Pinus patula. Species of the genus Laccaria and Hebeloma were chosen according to previous studies which have demonstrated their abundance and biocultural importance in the center of Mexico (Pérez-Moreno et al., 2008).
Materials and methods
Preparation of ectomycorrhizal inoculants based on powder spores. Species sporomes of the edible ectomycorrhizal fungi belonging to the genera Hebeloma and Laccaria (Figure 1a and 2a), were acquired in the market of Ozumba, State of Mexico located at 19° 02’ 11” north latitude and 98° 47’ 48” west longitude, during the months of august and september of 2016. Once the sporomas were acquired, they were classified by species, according to the diagnostic characteristics specified by Carrasco-Hernández et al. (2010, 2015).
The stipe was cut and only the pileus was dehydrated in a dehydrator type trays with steam (brand JERSA) at a temperature of 33 ±2 °C for a period of 16 hours (Figures 1b and 1c). The already dehydrated inoculum was milled in an industrial mill (Figure 1d.), with an aperture sheet of 1 mm at the outlet, to allow homogenization of the inoculum thus produced. The inoculum obtained was placed in plastic bags of 500 g capacity and 1.5 mL Eppendorf tubes (Figures 1e and 1f). The inoculant was stored at 3 °C until use. Fresh and dry weight were recorded, and these data were used for cost analysis.
Cost analysis
For the financial analysis of powder inoculum preparation, the following costs were taken into account: mushroom price, transport, manpower separation by species, use of dehydrator, grinding and storage. All costs were expressed in mexican pesos.
Cost of the fungus (Ch): the cost of fresh fungus of Laccaria and Hebeloma was 60 pesos per kilo. However, due to its high water content, the cost of one gram of dehydrated fungus was calculated which was calculated from the amount of fresh fungus acquired in kilos (Hr), the price per kilogram of mushroom (P) and the amount of dehydrated inoculum obtained in kilos (Ci). In order to obtain the price in grams, it was divided by 1 000. For this, the following model was used:
Ch=(Hr)(P)Ci/1000
Cost of separation by species (Cse): based on previous evaluations it was determined that a person is required to separate 5 kg of mushrooms in 6 hours and a payment of $80.04 per person was considered, taking into account Mexico’s general minimum wage for the year 2017 (DOF, 2016). The cost of separation by species (Cse), was calculated with the following formula: Cse=Hr5X 100 Cost of transport for the acquisition of the fungus (Ct): in this case the cost of the payment of the personnel (Cp) for the acquisition of the mushroom and driver who was paid$80.04 per person was considered. The cost of gasoline (Cg) for the transfer to <the mushroom acquisition area was also considered, considering the liter of gasoline at $16.50. Ct= Cp+Cg Cost for dehydration (Cdh): the costs for the use of the dehydrator were as follows: 1 to 5 kg were paid$500, 5 to 30 kg were paid $1 000 and 31 to 60 kg were paid$ 1 500. Costs increased because more time was required for the use of the dehydrator.
Grinding cost (Cmo): 1 to 5 kg were paid $50; 6 to 30 kg were paid$100 and from 31 to 60 kg were paid $150. The greater the quantity of fungus, the greater the cost of electricity required by the mill. Cost of storage (Cre): this cost was$ 50 per month of storage and a maximum storage of one year was considered, since the viability of the spores is maintained during this time (Brundrett et al., 1996b).
Cost of inoculant per gram (CI): The cost was calculated from the sum of the cost of the fungus and the costs of preparing the inoculant between the amount of dehydrated pileus obtained.
CI=Chp1+CpiPs
Where: Chp1= average of the average costs of the four species of Laccaria and of the three species of Hebeloma, in the four collections made.
Σ Cpi= sum of transport costs (Ct), separation (Cse), dehydration (Cdh), grinding (Cmo) and storage (Cre).
Ps = number of dry picoles obtained in g.
Preparation of ectomycorrhizal inoculant based on spores in liquid. The acquisition of the fungus for preparation of ectomycorrhizal inoculant based on spores in liquid was also carried out in the Ozumba market. Sporomes acquired from the genus Laccaria were separated by species. Three species were identified: L. laccata, L. bicolor and L. proxima. In the case of Hebeloma, three species were identified: H. leucosarx, H. mesophaeum and H. alpinum. Specimens of Suillus spp. and the following species were identified: S. pseudobrevipes, S. granulatus and S. brevipes.
The preparation of the spore-based liquid inoculant consisted of grinding the pileus of each species separately in a homemade blender at a dose of 30 g of fresh pileus per 100 mL of purified water (Figure 2b). Once ground, the inoculum thus obtained was stored in five liter plastic containers (Figure 2c) and refrigerated at 3 °C, until use. In order to know the spore concentration of the inoculant in liquid of each species, the spores were counted with the Neubauer chamber. The camera is divided into 9 main quadrants. To calculate the spore concentration (CE), per cm3 or mL, the spores of the five main quadrants were counted: A, B, C, D and E (Figure 2e) and the following formula was used:
CE=A, B, C, D, E2000
Cost analysis. For the financial analysis of the ectomycorrhizal liquid inoculant preparation the following costs were taken into account: fungi, transport, water, containers, use of blender, electric power, fungus separation by species and storage. As for the preparation of powdered ectomycorrhizal inoculant, the price of the mushroom kilo at 60 pesos was considered and the same variables were taken for the analysis of transport cost and separation by species. To calculate the cost of the final inoculant, all costs were added and divided by the amount of inoculum obtained in milliliters.
Evaluation of the liquid ectomycorrhizal inoculant: the seeds of P. patula were put to germinate in a substrate of pine bark, river sand and forest floor in a ratio of 2:2:1, previously sterilized and inside a plastic tube with a capacity of 350 mL. One month after having germinated, the seedlings were applied the first inoculation with 5 mL of the inoculum (Figure 1d) and after two weeks another dose of 5 mL of the spore-based inoculants was applied in liquid of L. proxima, H. mesophaeum and S. pseudobrevipes separately in 20 pines per fungus species.
In addition, 20 uninoculated pine trees were maintained that corresponded to the controls. These fungal species were chosen because they were collected in greater quantity in 2016. After maintaining the plants in the greenhouse, the percentage of external mycelium was evaluated (Figure 2f) and the interval was found: 0 to 25%, from 25 to 50%, from 50 to 75% and from 75 to 100%. (Table 4), as an indicator of the percentage of ectomycorrhizal colonization. During this period they were irrigated every third day and no fertilizers or fungicides were applied.
Results and discussion
One of the greatest impacts of logging is the change in the composition of the community of ectomycorrhizal fungi, since these are altered by the chemical and biological changes that occur in the soil after deforestation (Bradley, 2001; Jones et al., 2003). It should be noted that the mycorrhizal association according to Dupponnois et al. (2011), 95% of native vegetation areas are present that have not been disturbed, while this is less than 1% in disturbed sites.
Due to the above, it is essential that in the nursery the appropriate ectomycorrhizals are introduced that adapt to the plant species and also to the new conditions of the area that is to be regenerated, especially in highly degraded areas. In this sense, it is very important to know the technologies for preparation of ectomycorrhizal inoculants and the costs that would imply for their application in a large-scale nursery.
In the species studied, the average humidity percentage varied from 89 to 91% for the Laccaria case and from 91.6 to 94.4% for the Hebeloma species. The remaining percentage corresponds to dry matter. In the case of Laccaria, an average of 4.8 to 5.5% was obtained for the pileus and 2.6 to 5.3% for the stipe of dry matter. Regarding the Hebeloma species, the dry matter pile percentage was 4.3 to 5% and from 1.2 to 2.7% for the stipe. In both cases the highest percentage of dry matter was recorded in the pileus.
It should be noted that only the pileus is used for preparation of ectoomycorrhizal inoculant of Laccaria spp. and Hebeloma spp. because in the sheets is where the spores are, which are the reproductive structures from which the mycelium with ectomycorrhizal colonization capacity is produced. The data in Table 1 and 2 show the amount of fresh fungi collected for Laccaria spp. and Hebeloma spp. respectively, as well as the quantities of dry pileus (inoculum) used for the cost analysis. The final cost of producing the ectomycorrhizal powder inoculant for the species evaluated was 2 pesos per gram of ectomycorrhizal inoculant.
Table 1 Fresh and dry weight (kg) of Laccaria spp. in the five collections made in the market of Ozumba, State of Mexico.
Characteristics L. proxima L. laccata L. proximella L. bicolor A1 Fresh weight Pilea 39 0.789 2.8 0.643 Stipe 13 0.424 2.2 0.302 Total 52.6 1.2 5 0.945 Dry weight Pilea 2.5 0.071 0.283 0.085 Stipe 1.3 0.064 0.167 0.054 Total 3.8 0.135 0.45 0.139 A2 Fresh weight Pilea 5.9 4.4 0.45 0.43 Stipe 2.7 2.5 0.17 0.42 Total 8.6 6.9 0.62 0.85 Dry weight Pilea 0.473 0.323 0.038 0.035 Stipe 0.289 0.202 0.018 0.04 Total 0.762 0.525 0.056 0.075 A3 Fresh weight Pilea 29.8 0.101 3.5 0.069 Stipe 11.5 0.074 2.8 0.089 Total 41.3 0.175 6.3 0.158 Dry weight Pilea 2.2 0.01 0.369 0.005 Stipe 0.704 0.008 0.201 0.007 Total 2.9 0.017 0.57 0.012 A4 Fresh weight Pilea 1.4 1 0.068 0.026 Stipe 0.689 0.66 0.079 0.039 Total 2 1.66 0.147 0.065 Dry weight Pilea 0.106 0.075 0.005 0.002 Stipe 0.056 0.058 0.007 0.004 Total 0.162 0.133 0.012 0.006
A1= acquisition of mushrooms on the date August 23, 2016; A2= acquisition of mushrooms on the date August 30, 2016; A3= acquisition of mushrooms on the date September 6, 2016; A4= acquisition of mushrooms on the date September 13, 2016.
Table 2 Fresh and dry weight (g) of Hebeloma spp. in the five collections made in the market of Ozumba, State of Mexico.
Characteristics H. leucosarx H. mesophaeum H. aff. alpinum A1 Fresh weight Pilea 669 439.5 287.3 Stipe 223 133.3 108.6 Total 892 572.8 395.9 Dry weight Pilea 54.2 28.5 20.5 Stipe 24.5 9.8 9.1 Total 78.7 38.3 29.6 A2 Fresh weight Pilea 435 60 440 Stipe 200 20 190 Total 635 80 630 Dry weight Pilea 35.7 3 33 Stipe 18 1 18 Total 53.7 4 51 A3 Fresh weight Pilea 182.2 205.8 335 Stipe 70.8 67.1 98.1 Total 253 272.9 433.1 Dry weight Pilea 14.4 11.3 19.3 Stipe 6.7 2.7 5 Total 21.1 14 24.3 A4 Fresh weight Pilea 40 775 67.5 Stipe 15 250 33 Total 55 1025 100.5 Dry weight Pilea 3 45.7 5 Stipe 1.5 10.3 3 Total 4.5 56 8
A1= acquisition of mushrooms on the date August 23, 2016; A2= acquisition of mushrooms on the date August 30, 2016; A3= acquisition of mushrooms on the date September 6, 2016; A4= acquisition of mushrooms on the date September 13, 2016.
In previous works this type of inoculant (3g seedling-1), in P. greggii, P. patula and P. pseudostrobus has been applied at a spore concentration of 106 to 108 per gram and high efficiency results have been obtained with percentages high mycorrhization that have varied from 70 to 90% (Carrasco-Hernández, 2011; Mendez-Neri et al., 2011; Martínez-Reyes, 2012). If 3 g of inoculant powder-based inoculant are applied per plant, the cost of inoculation per plant is $6. The cost of producing one kilogram of inoculant ectomycorrhizal powder is$2 000, if you consider applying 3 g by plant this would reach to inoculate 333 plants. However, if the dose is reduced by half 1.5 g per seedling, the cost of the inoculant would be $3, which has also been shown to be effective (Rendón et al., 2014). The cost of production of P. greggii and P. pseudostrobus is 2.72 and 2.98 pesos respectively in the nursery of the Autonomous University of Chapingo. The plant that is offered at this price is a 10-month plant for P. greggii and 12 months for P. pseudostrobus and are produced in plastic tubes (black virgin polypropylene containers with a capacity of 140 mL) in a peat substrate-vermiculite-perlite in a proportion of 50, 30 and 20 respectively. To these plants were applied eight fertilizations and four fumigations per month. The fertilizers used and the doses of N varied according to the stage of the pine and were the following: as initiator: 9-45-15 to 50 ppm of N, in its growth stage: calcium nitrate combined with 20-20-20 to 200 ppm of N and as finalizer: 4-25-35 to 50 ppm of N. From the above it is deduced that the cost of a mycorrhized plant with the powder inoculum, would have a price of$5.72 for P. greggii and of $5.98 for P. pseudostrobus at a dose of 1.5 g of inoculum per plant. It is important to mention that studies are needed related to the minimum doses of ectomycorrhizal inoculant powder, which can reach levels of mycorrhization abundant (higher than 70%) and reduce costs. It should be noted that CONAFOR (2010) takes into account mycorrhiza as an important quality index and that it must cover at least 40% of the root ball so that it is considered an optimum quality plant to be taken to the field. An alternative form of preparation of ectomycorrhizal inoculant is to take the fresh pileus and grind it for its application as a liquid inoculant. The cost per ml of liquid ectomycorrhizal inoculant was$0.05 per mL and $50 per liter. The concentrations of spores varied according to the species (Table 3). The ectomycorrhizal inoculant based on spores in liquid prepared in the present study was inoculated in Pinus patula to test its effectiveness. The fungi inoculated were: L. proxima, H. mesophaeum and S. pseudobrevipes and the majority of pines presented high percentages of mycorrhization (75% to 100%), which demonstrates their effectiveness (Table 4). Table 3 Concentration of spores per cm3 or mL of the inoculant in prepared liquid. Spores Number of spores cm-3 L. laccata 7.9 x 105 L. proxima 8.7 x 105 L. bicolor 4.66 x 105 H. mesophaeum 5.5 x 106 H. leucosarx 7.2 x 106 H. alpinum 3.5 x 106 Table 4 Percentage of external mycelium in Pinus patula inoculated with three species of edible ectomycorrhizal fungi one year after the application of the ectomycorrhizal inoculant in liquid. Percentage Control L. proxima H. mesophaeum S. pseudobrevipes 0 a 25 20 1 0 0 25 a 50 7 5 2 50 a 75 5 2 2 75 a 100 7 13 16 According to evaluations developed in the present work with 10 mL of liquid inoculum per plant, optimal mycorrhization values are obtained and the price would be$0.50 per plant, which substantially reduces the cost compared with the ectomycorrhizal powder inoculant.
The cost of the powder ectomycorrhizal inoculant evaluated in the present work was of $2 000 kg-1, which is lower compared to the Ecto-Rhyza product of the PHC company, although if the amount of inoculum needed per plant is considered, the product is more expensive than those handled by this company (Table 5). It should be noted that the inoculum evaluated in the present work has not been tested in smaller quantities, which would substantially reduce the cost per plant. In addition to this, the PHC company does not show greenhouse bioassays on the label of its products where it can be confirmed that the concentrations they manage can reach high mycorrhization percentages (greater than 70%). Table 5 Cost of ectomycorrhizal inoculants. Name of the company and location Product Content Cost in mexican pesos Cost of inoculum per plant Source Forest and applied mycology Spain Ectoplant Irrigation Esporas de Pisolithus tinctorius, Scleroderma spp., Rhizopogon spp.,$23 423.85 L-1 Enough to 25 000 plants $0.93 1 Spain Ectoplant tablets Rhizopogon spp., Pisolithus tinctorius, Scleroderma verrucosum y Suillus spp. 500 tablets per$1 247.64 Enough to 500 plants $2.4 MycoGrow® MycoGrow™ Micronized Mix of spores of 4 different species of endomycorrhizal fungi and 7 ectomycorrhizal fungi. 28 g per$88.15 The cost is variable since it will depend on the size of the seed 2 United States Endo/Ecto Enough to 453.592 g of seed MycoGrow™ Soluble Mixture of spores of 9 different species of endomycorrhizal fungi and 10 ectomycorrhizal fungi as well as two disease-inhibiting species and 12 beneficial bacteria. 453.592 g per $1 423.73 It can reach from 2 000 to 4 000 plants, which will depend on the size of the plant and method of application. From$0.30 to $0.70 if considered for 2 000 and 4 000 plants respectively Plant Success™ Tablets compressed with concentrate of 7 spores of endomycorrhizal fungi and 5 spores of ectomycorrhizal fungi. 150 tablets per$444.02 Enough to 150 seedlings $2.9 Planth Health Care of Mexico PHC® Ecto-Rhyza® 250 million cfu g of spores of Pisolithus tinctorius and 4 strains of Trichoderma harzianum (5x10) cfu g-1.$ 5300 kg-1 Enough to 100 000 plants $0.05 3 Mexico Enough to 100 000 plants MycorTree® Ecto- Injectable ® Spore of Pisolithus tinctorius, Scleroderma citrinum, rhizobacteria and cassava extracts. 226 g$1 400 $0.09 Enough to 15 000 plants The cost of production of the inoculum in liquid evaluated in the present work is$0.05 per mL and \$50 pesos per liter, which would reach 100 plants in a dose of 10 mL per plant. This price was similar to the product Mycogrow soluble and PHC Ectorhyza and slightly lower in cost to the product Ectoplant irrigation (Table 5).
Conclusions
The ectomycorrhizal inoculant based on liquid spores has a lower cost when compared to the ecomicorrízico inoculant based on spores in powder.
The ectomycorrhizal inoculant based on spores in liquid is effective and also has the potential to originate high percentages of mycorrhization as well as with the ectomycorrhizal inoculant based on powder spores.
The economic feasibility, comparable with the current prices of commercial inoculants existing in the international market, of the production of inoculants based on powder or liquid spores produced for neotropical tree species is demonstrated.
It is necessary to encourage the creation of national companies that produce ectomycorrhizal inoculants based on fungi native to Mexico, since acquiring and introducing species from other countries carries the risk of serious ecological consequences, such as the possible displacement of native species of the country and economic and social benefits as the creation of local and regional jobs.
Gratefulness
The first author is grateful for the financing granted by the National Council of Science and Technology (CONACYT), for the realization of a postdoctoral stay. They also appreciate the support of the CONACYT Project 246674
REFERENCES
Bradley, R. L. 2001. An alternative explanation for the post-discurbance NO3- flush in some forest ecosystems. Ecology Letter. 4(5):412-416. [ Links ]
Brundrett, M.; Bougher, N.; Dell, B.; Grove, T. and Malajczuk, N. 1996b. Working with mycorrhizas in forestry and agriculture. ACIAR Monograph. 374 p. [ Links ]
Brundrett, M. C.; Ashwath, N; and Jasper, D. A. 1996a. Mycorrhizas in the Kakadu region of tropical Australia. II. Propagules of mycorrhizal fungi in disturbed habitats. Plant and Soil, 184(1):173-184. [ Links ]
Bruns T. D.; Peay, K. G.; Boynton, P. J.; Grubisha, L. C.; Hynson, N. A.; Nguyen N. H. and Rosenstock. N. P. 2009. Inoculum potential of Rhizopogon spores increases with time over the first 4 yr of a 99-yr spore burial experiment. New Phytol. 181(2):463-470. [ Links ]
Carrasco, H. V.; Pérez, M. J; Espinosa, H. V; Almaraz, S. J. J.; Quintero, L. R y Torres, A. M. 2010. Caracterización de micorrizas establecidas entre dos hongos comestibles silvestres y pinos nativos de México. Rev. Mex. Cienc. Agríc. 1(4):567-577. [ Links ]
Carrasco, H. V.; Pérez, M. J; Espinosa, H. V; Almaraz, S. J. J.; Quintero, L. R. y Torres, A. M. 2011. Contenido de nutrientes e inoculación con hongos ectomicorrízicos comestibles en dos pinos neotropicales. Rev. Chilena de Historia Natural. 84(1):83-96. [ Links ]
Carrasco, H. V.; Pérez, M. J.; Quintero, L. R.; Espinosa, S. T.; Lorenzana, F. A. and Espinosa, H. V. 2015. Edible species of the fungal genus Hebeloma and two neotropical pines. Pak. J. Bot. 43(1):319-326. [ Links ]
CONAFOR. 2010. Comisión Nacional Forestal Forestal. Prácticas de reforestación. Manual básico. CONAFOR- SEMARNAP. Jalisco, México. 64 p. [ Links ]
DOF. 2016. Diario Oficial de la Federación. De la comisión nacional de los salarios mínimos que fija los salarios mínimos general y profesionales vigentes a partir del 01 enero, 2017. http://www.dof.gob.mx/nota-detalle.php?codigo=5283125&fecha=21/12/2012. [ Links ]
Duponnois R.; Bâ, A.; Mousain, D.; Galiana, A; Baudoin, E.; Dreyfus, B. and Prin, Y. 2011. Biotechnological processes used in controlled ectomycorrhizal practices. In: Ray, M. and Varma, A. (Eds.). Diversity and biotechnology of ectomycorrhizae. Soil Biol. 25. Springer, Berlin Heidelberg. 143-155 pp. [ Links ]
Jones, M. D.; Durall, D. M. and Cairney, J. W. G. 2003. Ectomycorrhizal fungal communities in young forest stands regenerating after clearcut logging. New Phytol. 157(3):399-422. [ Links ]
Landis, T. D.; Tinus, R. W.; McDonald, S. E. and Barnett, J. P. 1989. The biological component: nursery pest and mycorrhizae. The container tree nursery manual. Agric. Handbk. 674. Washington, DC: US. Department of Agriculture, Forest Service. Vol 5. 159 p. [ Links ]
Martínez, R. M.; Pérez, M. J.; Villareal, R. L.; Ferrera, C. R.; Xoconostle, C. B.; Várgas, H. J. J. y Honrubia, G. M. 2012. Crecimiento y contenido nutrimental de Pinus greggii Engelm. Inoculado con el hongo comestible ectomicorrizico Hebeloma mesophaeum (Pers.) Quél. Rev. Chapingo Ser. Cienc. Fores. Amb. 18 (2):183-192. [ Links ]
Méndez, N. M.; Pérez, M. J.; Quintero, L. R; Herández, A. E. y Lara, H. A. 2011. Crecimiento y contenido nutrimental de Pinus greggii inoculados con tres hongos comestibles ectomicorrízicos. Terra Latinoam. 29(1):73-81. [ Links ]
Nguyen, N. H.; Hynson, N. A. and Bruns, T. D. 2012. Stayin’ alive: survival of mycorrhizal fungal propagules from 6-yr-old forest soil. Fungal Ecol. 5(6):741-746. [ Links ]
Oliveira L. P; Rossi, M. J.; Furigo J. A.; Silva F.; Germano, N. and Oliveira V. L. 2006. Viability and infectivity of an ectomycorrhizal inoculum produced in an airlift bioreactor and immobilized in calcium alginate. Braz. J. Microbiol. 37(3):251-255. [ Links ]
Pera, J.; Álvarez, I. F. y Parlade, J. 1998. Eficacia del inóculo miceliar de 17 especies de hongos ectomicorricicos para la micorrización controlada de: Pinus pinaster, Pinus radiata y Pseudotsuga menziesii en contenedor. Invest. Agr. Sist. Recur. For. 7(1 y 2):140-153. [ Links ]
Pérez, M. J.; Martínez, R. M; Yesca, P. A.; Delgado, A. A. and Xoconostle, C. B. 2008. Wild mushroom market in central Mexico and a case study at Ozumba. Econ. Bot. 62(3):425-436. [ Links ]
Rendón, P. A.; López, R. L.; Portillo, M. E.; Tapia, H. A.; Sánchez, A. M.; Pérez, M. J.; y Carcaño, M. M. 2014. Evaluación del crecimiento en invernadero de Pinus Montezumae Lamb. al tratamiento con bacterias y hongos benéficos. In: XXXVIII. Congreso de la Sociedad Mexicana de la Ciencia del Suelo. 326-332 pp. [ Links ]
Rossi, M. J.; Furigo, J. R. and Oliveira V. L. 2007. Inoculant production of ectomycorrhizal fungi by solid and submerged fermentations. Food Technol. Biotechnol. 45(3):275-284. [ Links ]
Received: December 00, 2017; Accepted: February 00, 2018
Este es un artículo publicado en acceso abierto bajo una licencia Creative Commons
| 2022-05-24T19:15:37 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.59391850233078, "perplexity": 12363.850556838057}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662573189.78/warc/CC-MAIN-20220524173011-20220524203011-00687.warc.gz"}
|
https://ceres.larc.nasa.gov/science/publications/
|
# Publications
## 2022
Andersen, Hendrik; Cermak, Jan; Zipfel, Lukas; Myers, Timothy A.Andersen, H., J. Cermak, L. Zipfel, T. A. Myers, 2022: Attribution of Observed Recent Decrease in Low Clouds Over the Northeastern Pacific to Cloud-Controlling Factors. Geophysical Research Letters, 49(3), e2021GL096498. doi: 10.1029/2021GL096498. Marine low clouds cool the Earth's climate, with their coverage (LCC) being controlled by their environment. Here, an observed significant decrease of LCC in the northeastern Pacific over the past two decades is linked quantitatively to changes in cloud-controlling factors. In a comparison of different statistical and machine learning methods, a decrease in the inversion strength and near-surface winds, and an increase in sea surface temperatures (SSTs) are unanimously shown to be the main causes of the LCC decrease. While the decreased inversion strength leads to more entrainment of dry free-tropospheric air, the increasing SSTs are shown to lead to an increased vertical moisture gradient that enhances evaporation when entrainment takes place. While the LCC trend is likely driven by natural variability, the trend-attribution framework developed here can be used with any method in future analyses. We find the choice of predictors is more important than the method. satellite data; low clouds; trend analysis; machine learning; cloud-controlling factors
Andrews, Timothy; Bodas-Salcedo, Alejandro; Gregory, Jonathan M.; Dong, Yue; Armour, Kyle C.; Paynter, David; Lin, Pu; Modak, Angshuman; Mauritsen, Thorsten; Cole, Jason N. S.; Medeiros, Brian; Benedict, James J.; Douville, Hervé; Roehrig, Romain; Koshiro, Tsuyoshi; Kawai, Hideaki; Ogura, Tomoo; Dufresne, Jean-Louis; Allan, Richard P.; Liu, ChunleiAndrews, T., A. Bodas-Salcedo, J. M. Gregory, Y. Dong, K. C. Armour, D. Paynter, P. Lin, A. Modak, T. Mauritsen, J. N. S. Cole, B. Medeiros, J. J. Benedict, H. Douville, R. Roehrig, T. Koshiro, H. Kawai, T. Ogura, J. Dufresne, R. P. Allan, C. Liu, 2022: On the Effect of Historical SST Patterns on Radiative Feedback. Journal of Geophysical Research: Atmospheres, 127(18), e2022JD036675. doi: 10.1029/2022JD036675. We investigate the dependence of radiative feedback on the pattern of sea-surface temperature (SST) change in 14 Atmospheric General Circulation Models (AGCMs) forced with observed variations in SST and sea-ice over the historical record from 1871 to near-present. We find that over 1871–1980, the Earth warmed with feedbacks largely consistent and strongly correlated with long-term climate sensitivity feedbacks (diagnosed from corresponding atmosphere-ocean GCM abrupt-4xCO2 simulations). Post 1980, however, the Earth warmed with unusual trends in tropical Pacific SSTs (enhanced warming in the west, cooling in the east) and cooling in the Southern Ocean that drove climate feedback to be uncorrelated with—and indicating much lower climate sensitivity than—that expected for long-term CO2 increase. We show that these conclusions are not strongly dependent on the Atmospheric Model Intercomparison Project (AMIP) II SST data set used to force the AGCMs, though the magnitude of feedback post 1980 is generally smaller in nine AGCMs forced with alternative HadISST1 SST boundary conditions. We quantify a “pattern effect” (defined as the difference between historical and long-term CO2 feedback) equal to 0.48 ± 0.47 [5%–95%] W m−2 K−1 for the time-period 1871–2010 when the AGCMs are forced with HadISST1 SSTs, or 0.70 ± 0.47 [5%–95%] W m−2 K−1 when forced with AMIP II SSTs. Assessed changes in the Earth's historical energy budget agree with the AGCM feedback estimates. Furthermore satellite observations of changes in top-of-atmosphere radiative fluxes since 1985 suggest that the pattern effect was particularly strong over recent decades but may be waning post 2014. observations; climate models; climate feedback; climate sensitivity; pattern effect; historical record
Aparna, A. R.; Girishkumar, M. S.Aparna, A. R., M. S. Girishkumar, 2022: Mixed layer heat budget in the eastern equatorial Indian Ocean during the two consecutive positive Indian Ocean dipole events in 2018 and 2019. Climate Dynamics. doi: 10.1007/s00382-021-06099-8. The Indian Ocean hosted a strong positive Indian Ocean Dipole (pIOD) event in 2019–2020, and a weak event in 2018–2019, such as the magnitude of the cold sea surface temperature anomaly (SSTA) during June-December in the former case is a factor of two higher (~ − 1.5 °C) than the latter (~ − 0.75 °C) at the western periphery of the eastern IOD zone at 5° S, 95° E. The plausible mechanisms responsible for this difference in the SSTA between these two events are examined using the mixed layer heat budget estimate using the moored buoy measurements. It is found that the enhanced cooling during June-December in 2019–2020 is determined primarily by the anomalous cooling due to the vertical processes associated with the combined effect of the anomalous thin barrier layer (BL), shallow thermocline, weak near-surface stratification, and strong wind speed induced vertical mixing, and secondarily by the enhancement in the latent heat flux (LHF) loss from the ocean. Conversely, the magnitude of cooling due to the vertical processes is much smaller in 2018–2019 due to the near-climatological states such as a thick BL, deep thermocline, and weak wind speed. During these events, the warming tendency by the horizontal advection dampens the cooling tendency associated with the vertical processes and LHF. These characteristics are distinct from the past study that suggested that the horizontal advection was responsible for the cool SSTA at the exact location during an extreme pIOD event in 2006–2007.
Atlas, R.l.; Bretherton, C.s.; Khairoutdinov, M.f.; Blossey, P.n.Atlas, R., C. Bretherton, M. Khairoutdinov, P. Blossey, 2022: Hallett-Mossop rime splintering dims cumulus clouds over the Southern Ocean: New insight from nudged global storm-resolving simulations. AGU Advances, n/a(n/a), e2021AV000454. doi: 10.1029/2021AV000454. In clouds containing both liquid and ice with temperatures between − 3°C and − 8°C, liquid droplets collide with large ice crystals, freeze, and shatter, producing a plethora of small ice splinters. This process, known as Hallett-Mossop rime splintering, and other forms of secondary ice production, can cause clouds to reflect less sunlight and to have shorter lifetimes. We show its impact on Southern Ocean shallow cumuli using a novel suite of five global storm-resolving simulations, which partition the Earth’s atmosphere into 2-4 km wide columns. We evaluate simulated clouds and radiation over the Southern Ocean with aircraft observations from the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES), and satellite observations from Clouds and the Earth’s Radiant Energy System (CERES) and Himawari. Simulations with large concentrations of ice crystals in boundary layer clouds, which agree better with SOCRATES observations, have reduced mixed-phase cumulus cloud cover and weaker shortwave cloud radiative effects that are less biased compared with CERES. Using a pair of simulations differing only in their treatment of Hallett-Mossop rime splintering, we show that including this process increases ice crystal concentrations in cumulus clouds and weakens shortwave cloud radiative effects over the Southern Ocean by 10 W m−2. We also demonstrate the key role that global storm-resolving models can play in detangling the effects of clouds on Earth’s climate across scales, making it possible to trace the impact of changes in individual cumulus cloud anvils (10 km2) on the radiative budget of the massive Southern Ocean basin (108 km2). Southern Ocean; Boundary layer; Global cloud-resolving simulations; Hallett-Mossop rime splintering; Open cell cumuli; Secondary ice production
Atmoko, Dwi; Lin, Tang-HuangAtmoko, D., T. Lin, 2022: Sea Salt Aerosol Identification Based on Multispectral Optical Properties and Its Impact on Radiative Forcing over the Ocean. Remote Sensing, 14(13), 3188. doi: 10.3390/rs14133188. The ground-based measurement of sea salt (SS) aerosol over the ocean requires the massive utilization of satellite-derived aerosol products. In this study, n-order spectral derivatives of aerosol optical depth (AOD) based on wavelength were examined to characterize SS and other aerosol types in terms of their spectral dependence related to their optical properties such as particle size distributions and complex refractive indices. Based on theoretical simulations from the second simulation of a satellite signal in the solar spectrum (6S) model, AOD spectral derivatives of SS were characterized along with other major types including mineral dust (DS), biomass burning (BB), and anthropogenic pollutants (APs). The approach (normalized derivative aerosol index, NDAI) of partitioning aerosol types with intrinsic values of particle size distribution and complex refractive index from normalized first- and second-order derivatives was applied to the datasets from a moderate resolution imaging spectroradiometer (MODIS) as well as by the ground-based aerosol robotic network (AERONET). The results after implementation from multiple sources of data indicated that the proposed approach could be highly effective for identifying and segregating abundant SS from DS, BB, and AP, across an ocean. Consequently, each aerosol’s shortwave radiative forcing and its efficiency could be further estimated in order to predict its impact on the climate. particle size; sea salt aerosol; aerosol optical depth (AOD); complex refractive index; normalized derivative aerosol index (NDAI); spectral derivatives
Bai, Jianhui; Zong, Xuemei; Lanconelli, Christian; Lupi, Angelo; Driemel, Amelie; Vitale, Vito; Li, Kaili; Song, TaoBai, J., X. Zong, C. Lanconelli, A. Lupi, A. Driemel, V. Vitale, K. Li, T. Song, 2022: Long-Term Variations of Global Solar Radiation and Its Potential Effects at Dome C (Antarctica). International Journal of Environmental Research and Public Health, 19(5), 3084. doi: 10.3390/ijerph19053084. An empirical model to predict hourly global solar irradiance under all-sky conditions as a function of absorbing and scattering factors has been applied at the Dome C station in the Antarctic, using measured solar radiation and meteorological variables. The calculated hourly global solar irradiance agrees well with measurements at the ground in 2008–2011 (the model development period) and at the top of the atmosphere (TOA). This model is applied to compute global solar irradiance at the ground and its extinction in the atmosphere caused by absorbing and scattering substances during the 2006–2016 period. A sensitivity study shows that the responses of global solar irradiance to changes in water vapor and scattering factors (expressed by water vapor pressure and S/G, respectively; S and G are diffuse and global solar irradiance, respectively) are nonlinear and negative, and that global solar irradiance is more sensitive to changes in scattering than to changes in water vapor. Applying this empirical model, the albedos at the TOA and the surface in 2006–2016 are estimated and found to agree with the satellite-based retrievals. During 2006–2016, the annual mean observed and estimated global solar exposures decreased by 0.05% and 0.09%, respectively, and the diffuse exposure increased by 0.68% per year, associated with the yearly increase of the S/G ratio by 0.57% and the water vapor pressure by 1.46%. The annual mean air temperature increased by about 1.80 °C over the ten years, and agrees with the warming trends for all of Antarctica. The annual averages were 316.49 Wm−2 for the calculated global solar radiation, 0.332 for S/G, −46.23 °C for the air temperature and 0.10 hPa for the water vapor pressure. The annual mean losses of solar exposure due to absorbing and scattering substances and the total loss were 4.02, 0.19 and 4.21 MJ m−2, respectively. The annual mean absorbing loss was much larger than the scattering loss; their contributions to the total loss were 95.49% and 4.51%, respectively, indicating that absorbing substances are dominant and play essential roles. The annual absorbing, scattering and total losses increased by 0.01%, 0.39% and 0.28% per year, respectively. The estimated and satellite-retrieved annual albedos increased at the surface. The mechanisms of air-temperature change at two pole sites, as well as a mid-latitude site, are discussed. albedo; energy balance; air temperature; absorbing and scattering substances; climate and climate change
Baxter, Ian; Ding, QinghuaBaxter, I., Q. Ding, 2022: An Optimal Atmospheric Circulation Mode in the Arctic Favoring Strong Summertime Sea Ice Melting and Ice–Albedo Feedback. J. Climate, 35(20), 3027-3045. doi: 10.1175/JCLI-D-21-0679.1. Abstract The rapid decline of summer Arctic sea ice over the past few decades has been driven by a combination of increasing greenhouse gases and internal variability of the climate system. However, uncertainties remain regarding spatial and temporal characteristics of the optimal internal atmospheric mode that most favors summer sea ice melting on low-frequency time scales. To pinpoint this mode, we conduct a suite of simulations in which atmospheric circulation is constrained by nudging tropospheric Arctic (60°–90°N) winds within the Community Earth System Model, version 1 (CESM1), to those from reanalysis. Each reanalysis year is repeated for over 10 model years using fixed greenhouse gas concentrations and the same initial conditions. Composites show the strongest September sea ice losses are closely preceded by a common June–August (JJA) barotropic anticyclonic circulation in the Arctic favoring shortwave absorption at the surface. Successive years of strong wind-driven melting also enhance declines in Arctic sea ice through enhancement of the ice–albedo feedback, reaching a quasi-equilibrium response after repeated wind forcing for over 5–6 years, as the effectiveness of the wind-driven ice–albedo feedback becomes saturated. Strong melting favored by a similar wind pattern as observations is detected in a long preindustrial simulation and 400-yr paleoclimate reanalysis, suggesting that a summer barotropic anticyclonic wind pattern represents the optimal internal atmospheric mode maximizing sea ice melting in both the model and natural world over a range of time scales. Considering strong contributions of this mode to changes in Arctic climate, a better understanding of its origin and maintenance is vital to improving future projections of Arctic sea ice.
Boudala, Faisal S.; Milbrandt, Jason A.; Isaac, George A.Boudala, F. S., J. A. Milbrandt, G. A. Isaac, 2022: Evaluation of CanESM Cloudiness, Cloud Type and Cloud Radiative Forcing Climatologies Using the CALIPSO-GOCCP and CERES Datasets. Remote Sensing, 14(15), 3668. doi: 10.3390/rs14153668. In this study, the annual and seasonal climatology of cloud fraction (CF) and cloud type simulated by the Canadian Environmental System Models (CanESMs) version 5 (CanESM5) and version 2 (CanESM2) at their fully coupled and AMIP configurations were validated against the CALIPSO-GOCCP-based CF. The CFs produced using the CALIPSO-COSP simulator based on the CanESMs data at their atmospheric (AMIP) configuration are also evaluated. The simulated shortwave, longwave, and net cloud radiative forcing using the AMIP version of the CanESM5 were also validated against satellite observations based on the recent CERES radiation satellite products. On average, all models have a negative bias in the total CF with global mean biases (MBs) of 2%, 2.4%, 3.9%, 6.4%, 5.6%, and 7.1% for the coupled-CanESM5, AMIP-CanESM5, COSP-AMIP-CanESM5, coupled-CanESM2, AMIP-CanESM2, and COSP-AMIP-CanESM2, respectively, indicating that the CanESM5 has a smaller MB. There were no significant differences between AMIP and coupled versions of the model, but the COSP-based model-simulated data showed larger biases. Although the models captured well the climatological features of CF, they also exhibited a significant bias in CF reaching up to 40% over some geographical locations. This is particularly prevalent over the low level (LL) marine stratocumulus/cumulus, convectively active tropical latitudes that are normally dominated by high level (HL) clouds and at the polar regions where all models showed negative, positive, and positive bias corresponding to these locations, respectively. The AMIP-CanESM5 model performed reasonably well simulating the global mean cloud radiative forcing (CRF) with slight negative biases in the NetCRF at the TOA and surface that would be expected if the model has a positive bias in CF. This inconsistent result may be attributed to the parameterization of the optical properties in the model. The geographical distributions of the model bias in the NetCRF, however, can be significant reaching up to ±40 Wm−2 depending on the location and atmospheric level. The Pearson correlation showed that there is a strong correlation between the global distribution of model bias in NetCRF and CF and it is significantly influenced by the LL and HL clouds. cloud fraction; satellite data; cloud radiative forcing; GCM model evaluation
Cao, Yunfeng; Li, Manyao; Zhang, YuzhenCao, Y., M. Li, Y. Zhang, 2022: Estimating the Clear-Sky Longwave Downward Radiation in the Arctic from FengYun-3D MERSI-2 Data. Remote Sensing, 14(3), 606. doi: 10.3390/rs14030606. Surface longwave downward radiation (LWDR) plays a key role in determining the Arctic surface energy budget, especially in insolation-absent boreal winter. A reliable LWDR product is essential for understanding the intrinsic physical mechanisms of the rapid changes in the Arctic climate. The Medium-Resolution Spectral Imager (MERSI-2), a major payload of the Chinese second-generation polar-orbiting meteorological satellite, FengYun-3D (FY-3D), was designed similar to the NASA Moderate-Resolution Imaging Spectroradiometer (MODIS) in terms of the spectral bands. Although significant progress has been made in estimating clear-sky LWDR from MODIS observations using a variety of methods, few studies have focused on the retrieval of clear-sky LWDR from FY-3D MERSI-2 observations. In this study, we propose an advanced method to directly estimate the clear-sky LWDR in the Arctic from the FY-3D MERSI-2 thermal infrared (TIR) top-of-atmosphere (TOA) radiances and auxiliary information using the extremely randomized trees (ERT) machine learning algorithm. The retrieval accuracy of RMSE and bias, validated with the Baseline Surface Radiation Network (BSRN) in situ measurements, are 14.14 W/m2 and 4.36 W/m2, respectively, which is comparable and even better than previous studies. The scale effect in retrieval accuracy evaluation was further analyzed and showed that the validating window size could significantly influence the retrieval accuracy of the MERSI-2 clear-sky LWDR dataset. After aggregating to a spatial resolution of 9 km, the RMSE and bias of MERSI-2 retrievals can be reduced to 9.43 W/m2 and −0.14 W/m2, respectively. The retrieval accuracy of MERSI-2 clear-sky LWDR at the CERES SSF FOV spatial scale (approximately 20 km) can be further reduced to 8.64 W/m2, which is much higher than the reported accuracy of the CERES SSF products. This study demonstrates the feasibility of producing LWDR datasets from Chinese FY-3D MERSI-2 observations using machine learning methods. satellite observation; surface downward longwave radiation; Arctic region; machine learning; FengYun-3D; MERSI-2
Chakraborty, T.; Lee, X.; Lawrence, D. M.Chakraborty, T., X. Lee, D. M. Lawrence, 2022: Diffuse Radiation Forcing Constraints on Gross Primary Productivity and Global Terrestrial Evapotranspiration. Earth's Future, 10(8), e2022EF002805. doi: 10.1029/2022EF002805. The diffuse radiation fertilization effect—the increase in plant productivity in the presence of higher diffuse radiation (K↓,d)—is an important yet understudied aspect of atmosphere-biosphere interactions and can modify the terrestrial carbon, energy, and water budgets. The K↓,d fertilization effect links the carbon cycle with clouds and aerosols, all of which are large sources of uncertainties for our current understanding of the Earth system and for future climate projections. Here we establish to what extent observational and modeling uncertainty in sunlight's diffuse fraction (kd) affects simulated gross primary productivity (GPP) and terrestrial evapotranspiration (λE). We find only 48 eddy covariance sites with simultaneous sufficient measurements of K↓,d with none in the tropical climate zone, making it difficult to constrain this mechanism globally using observations. Using a land modeling framework based on the latest version of the Community Land Model, we find that global GPP ranges from 114 Pg C year−1 when using kd forcing from the Modern-Era Retrospective analysis for Research and Applications, version 2 reanalysis to a ∼7% higher value of 122 Pg C year−1 when using the Clouds and the Earth's Radiant Energy System satellite product, with especially strong differences apparent over the tropical region (mean increase ∼9%). The differences in λE, although smaller (−0.4%) due to competing changes in shaded and sunlit leaf transpiration, can be greater than regional impacts of individual forcing agents like aerosols. Our results demonstrate the importance of comprehensively and systematically validating the simulated kd by atmosphere modules as well as the response to differences in kd within land modules across Earth System Models. evapotranspiration; gross primary productivity; atmosphere-biosphere interactions; diffuse radiation fertilization effect; land-surface models
Chan, Man-Yau; Chen, Xingchao; Leung, L. RubyChan, M., X. Chen, L. R. Leung, 2022: A High-Resolution Tropical Mesoscale Convective System Reanalysis (TMeCSR). Journal of Advances in Modeling Earth Systems, 14(9), e2021MS002948. doi: 10.1029/2021MS002948. Modern global reanalysis products have greatly accelerated meteorological research in synoptic-to-planetary-scale phenomena. However, their use in studying tropical mesoscale convective systems (MCSs) and their regional-to-global impact has mostly been limited to supplying initial and boundary conditions for MCS-resolving simulations and providing information about the large-scale environments of MCSs. These limitations are due to difficulties in resolving tropical MCS dynamics in the relatively low-resolution global models and that tropical MCSs often occur over poorly observed regions. In this work, a Tropical MCS-resolving Reanalysis product (TMeCSR) was created over a region with frequent tropical MCSs. This region spans the tropical Indian Ocean, tropical continental Asia, Maritime Continent, and Western Pacific. TMeCSR is produced by assimilating all-sky infrared radiances from geostationary satellites and other conventional observations into an MCS-resolving regional model using the Ensemble Kalman Filter. The resulting observation-constrained high-resolution (9-km grid spacing) data set is available hourly during the boreal summer (June-August) of 2017, during which widespread severe flooding occurred. Comparisons of TMeCSR and European Center for Medium Range Weather Forecast Reanalysis version 5 (ERA5) against independent satellite retrievals indicate that TMeCSR's cloud and multiscale rain fields are better than those of ERA5. Furthermore, TMeCSR better captured the diurnal variability of rainfall and the statistical characteristics of MCSs. Forecasts initialized from TMeCSR also have more accurate rain and clouds than those initialized from ERA5. The TMeCSR and ERA5 forecasts have similar performances with respect to sounding and surface observations. These results indicate that TMeCSR is a promising MCS-resolving data set for tropical MCS studies. reanalysis; data assimilation; mesoscale convective system
Chao, Li-Wei; Muller, Jacob C.; Dessler, Andrew E.Chao, L., J. C. Muller, A. E. Dessler, 2022: Impacts of the Unforced Pattern Effect on the Cloud Feedback in CERES Observations and Climate Models. Geophysical Research Letters, 49(2), e2021GL096299. doi: 10.1029/2021GL096299. The equilibrium climate sensitivity estimated from different sources is inconsistent due to its dependence on the surface warming pattern. Cloud feedbacks have been identified as the major contributor to this so-called pattern effect. We find a large unforced pattern effect in CERES data, with cloud feedback estimated from two consecutive 125-month periods (March 2000–July 2010 and August 2010–December 2020) changing from −0.45 ± 0.85 to +1.2 ± 0.78 W/m2/K. When comparing to models, 27% of consecutive 10-year segments in CMIP6 control runs have differences similar to the observations. We also compare the spatial patterns in the CERES data to those in climate models and find they are similar, with the East Pacific playing a key role. This suggests that the impact of the unforced pattern effect can be significant and that models are capable of reproducing its global-average magnitude. climate models; cloud feedback; pattern effect
Chen, Guangcan; Zhang, Xiangdong; Fu, YunfeiChen, G., X. Zhang, Y. Fu, 2022: Diurnal Variation in Clouds and Radiative Budgets Over the Tibetan Plateau During Summer Using CERES Data. Journal of Geophysical Research: Atmospheres, 127(16), e2021JD036329. doi: 10.1029/2021JD036329. Diurnal variations in clouds and radiation budgets over four subareas of the Tibetan Plateau (TP) during summer (June–August) are analyzed using the Clouds and the Earth's Radiant Energy System (CERES) synoptic 1° (SYN1deg) data from 2000 to 2020. The results show that the total cloud amount decreases from southeast to northwest and is larger during daytime (71.1%) than nighttime (67.2%) over the entire TP. High-clouds develop in the afternoon, persist during nighttime, and dissipate after sunrise. Low clouds develop after sunrise and dissipate in the afternoon over the entire TP, but show opposite temporal variation over the Kunlun Mountains. The net radiation budget at the top-of-atmosphere reaches its maximum at noon. The surface net radiation budget is positive in the daytime and negative at nighttime. These features are mainly adjusted by the cloud distribution. The diurnal variations in heating rate over the four subareas are similar in the upper atmosphere but different in the lower layer. The low-atmosphere heating rate shows a maximum value over the center-south (CS) subarea, while it is lowest over the west (W) subarea. Internal cloud forcing has distinct regional differences over the four subareas: it shows a heating effect in the low atmosphere and a cooling effect in the middle atmosphere over the CS subarea, whereas over the W subarea it shows a radiative cooling effect in the low atmosphere and no significant radiative effect in the middle layer. The findings of this study help toward improving our understanding of the TP's energy cycle. diurnal variation; heating rate; cloud cover; internal cloud forcing; Tibet Plateau
Chen, Xingan; Huang, Yuefei; Nie, Chong; Zhang, Shuo; Wang, Guangqian; Chen, Shiliu; Chen, ZhichaoChen, X., Y. Huang, C. Nie, S. Zhang, G. Wang, S. Chen, Z. Chen, 2022: A long-term reconstructed TROPOMI solar-induced fluorescence dataset using machine learning algorithms. Scientific Data, 9(1), 427. doi: 10.1038/s41597-022-01520-1. Photosynthesis is a key process linking carbon and water cycles, and satellite-retrieved solar-induced chlorophyll fluorescence (SIF) can be a valuable proxy for photosynthesis. The TROPOspheric Monitoring Instrument (TROPOMI) on the Copernicus Sentinel-5P mission enables significant improvements in providing high spatial and temporal resolution SIF observations, but the short temporal coverage of the data records has limited its applications in long-term studies. This study uses machine learning to reconstruct TROPOMI SIF (RTSIF) over the 2001–2020 period in clear-sky conditions with high spatio-temporal resolutions (0.05° 8-day). Our machine learning model achieves high accuracies on the training and testing datasets (R2 = 0.907, regression slope = 1.001). The RTSIF dataset is validated against TROPOMI SIF and tower-based SIF, and compared with other satellite-derived SIF (GOME-2 SIF and OCO-2 SIF). Comparing RTSIF with Gross Primary Production (GPP) illustrates the potential of RTSIF for estimating gross carbon fluxes. We anticipate that this new dataset will be valuable in assessing long-term terrestrial photosynthesis and constraining the global carbon budget and associated water fluxes. Phenology; Ecosystem ecology
Chen, Zhe; Wang, Minghuai; Zhang, Haipeng; Lin, Shuheng; Guo, Zhun; Jiang, Yiquan; Zhou, ChenChen, Z., M. Wang, H. Zhang, S. Lin, Z. Guo, Y. Jiang, C. Zhou, 2022: Long-term change in low-cloud cover in Southeast China during cold seasons. Atmospheric and Oceanic Science Letters, 15(6), 100222. doi: 10.1016/j.aosl.2022.100222. Southeast China has comparable stratus cloud to that over the oceans, especially in the cold seasons (winter and spring), and this cloud has a substantial impact on energy and hydrological cycles. However, uncertainties remain across datasets and simulation results about the long-term trend in low-cloud cover in Southeast China, making it difficult to understand climate change and related physical processes. In this study, multiple datasets and numerical simulations were applied to show that low-cloud cover in Southeast China has gone through two stages since 1980—specifically, a decline and then a rise, with the turning point around 2008. The regional moisture transport plays a crucial role in low-cloud cover changes in the cold seasons and is mainly affected by the Hadley Cell in winter and the Walker Circulation in spring, respectively. The moisture transport was not well simulated in CMIP6 climate models, leading to poor simulation of the low-cloud cover trend in these models. This study provides insights into further understanding the regional climate changes in Southeast China. 摘要 中国东南地区在冬春冷季节盛行低云, 对局地能量平衡和水文循环有重要的作用. 本研究使用多套数据和数值模拟结果, 分析这一地区冷季节内低云云量在1980年至2017年的长期变化. 结果表明, 低云云量经历了先下降后上升的趋势变化, 转折点出现在2008年左右. 局地水汽通量输送在影响低云云量的变化中起着至关重要的作用, 其在冬季和春季分别受到哈德莱环流和沃克环流的影响. CMIP6中的气候模式对水汽通量输送的模拟能力欠佳, 影响了对低云云量的模拟结果. Hadley cell; Large-scale circulation; Low-cloud cover; Pacific walker circulation; 低云云量; 关键词:; 哈德莱环流; 大尺度环流场; 沃克环流
Chtirkova, Boriana; Folini, Doris; Correa, Lucas Ferreira; Wild, MartinChtirkova, B., D. Folini, L. F. Correa, M. Wild, 2022: Internal Variability of All-Sky and Clear-Sky Surface Solar Radiation on Decadal Timescales. Journal of Geophysical Research: Atmospheres, 127(12), e2021JD036332. doi: 10.1029/2021JD036332. Internal variability comprises all processes that occur within the climate system without any natural or anthropogenic forcing. Climate-driving variables like the surface solar radiation (SSR) are shown to exhibit unforced trends (i.e., trends due to internal variability) of magnitudes comparable to the magnitude of the forced signal even on decadal timescales. We use annual mean data from 50 models participating in the preindustrial control experiment (piControl) of the Coupled Model Intercomparison Project-Phase 6 (CMIP6) to give quantitative grid-box specific estimates of the magnitudes of unforced trends. To characterize a trend distribution, symmetrical around 0, we use the 75th percentile of all possible values, which corresponds to a positive trend with 25% chance of occurrence. For 30-year periods and depending on geographical location, this trend has a magnitude between 0.15 and 2.1 W m−2/decade for all-sky and between 0.04 and 0.38 W m−2/decade for clear-sky SSR. The corresponding area-weighted medians are 0.69 W m−2/decade for all-sky trends and 0.17 W m−2/decade for clear-sky trends. The influence of internal variability is on average six times smaller in clear-sky, compared to all-sky SSR. The relative uncertainties in the physical representation, derived from the CMIP6 inter-model spread, are ±32% for all-sky and ±43% for clear-sky SSR trends. Reasons for differences between models like horizontal resolution, aerosol handling, and the representation of atmospheric and oceanic phenomena are investigated. The results can be used in the analysis of observational time series by attributing a probability for a trend to be caused by internal variability, given its magnitude, length, and location. internal variability; surface solar radiation; dimming and brightening; CMIP6; unforced trends
Chu, Wenchao; Lin, Yanluan; Zhao, MingChu, W., Y. Lin, M. Zhao, 2022: Implementation and Evaluation of a Double-Plume Convective Parameterization in NCAR CAM5. J. Climate, 35(2), 617-637. doi: 10.1175/JCLI-D-21-0267.1. Abstract Performance of global climate models (GCMs) is strongly affected by the cumulus parameterization (CP) used. Similar to the approach in GFDL AM4, a double-plume CP, which unifies the deep and shallow convection in one framework, is implemented and tested in the NCAR Community Atmospheric Model version 5 (CAM5). Based on the University of Washington (UW) shallow convection scheme, an additional plume was added to represent the deep convection. The shallow and deep plumes share the same cloud model, but use different triggers, fractional mixing rates, and closures. The scheme was tested in single-column, short-term hindcast, and AMIP simulations. Compared with the default combination of the Zhang–McFarlane scheme and UW scheme in CAM5, the new scheme tends to produce a top-heavy mass flux profile during the active monsoon period in the single-column simulations. The scheme increases the intensity of tropical precipitation, closer to TRMM observations. The new scheme increased subtropical marine boundary layer clouds and high clouds over the deep tropics, both in better agreement with observations. Sensitivity tests indicate that regime-dependent fractional entrainment rates of the deep plume are desired to improve tropical precipitation distribution and upper troposphere temperature. This study suggests that a double-plume approach is a promising way to combine shallow and deep convections in a unified framework.
Cutler, Lauren; Brunke, Michael A.; Zeng, XubinCutler, L., M. A. Brunke, X. Zeng, 2022: Re-Evaluation of Low Cloud Amount Relationships With Lower-Tropospheric Stability and Estimated Inversion Strength. Geophysical Research Letters, 49(12), e2022GL098137. doi: 10.1029/2022GL098137. Lower-tropospheric stability (LTS) and estimated inversion strength (EIS) have a widely accepted relationship with low cloud amount and are key observational foundations for understanding and modeling low-level stratiform clouds. Using the updated surface-based and satellite cloud data, we find that low cloud amount is not as strongly correlated with LTS, and not as sensitive to LTS, as established in the past. EIS does not provide a stronger correlation with low cloud amount than LTS over all eight regions (including the midlatitudes). Further analyzing the relationships between LTS and EIS with different types of low clouds, we find that there is a strong correlation of LTS and EIS with stratocumulus only. This explains the weaker correlation of low cloud fraction (including cumulus, stratocumulus, and stratus) to both LTS and EIS. These results also suggest the need to re-evaluate these relationships in Earth system models.
Dauhut, Thibaut; Hohenegger, CathyDauhut, T., C. Hohenegger, 2022: The Contribution of Convection to the Stratospheric Water Vapor: The First Budget Using a Global Storm-Resolving Model. Journal of Geophysical Research: Atmospheres, 127(5), e2021JD036295. doi: 10.1029/2021JD036295. The deepest convection on Earth injects water in the tropical stratosphere, but its contribution to the global stratospheric water budget remains uncertain. The Global Storm-Resolving Model ICOsahedral Non-hydrostatic is used to simulate the moistening of the lower stratosphere for 40 days during boreal summer. The decomposition of the water vapor budget in the tropical lower stratosphere (TLS, 10°S–30°N, and 17–20 km altitude) indicates that the average moistening (+21 Tg) over the simulated 40-day period is the result of the combined effect of the vertical water vapor transport from the troposphere (+27 Tg), microphysical phase changes and subgrid-scale transport (+2 Tg), partly compensated by horizontal water vapor export (−8 Tg). The very deep convective systems, explicitly represented thanks to the employed 2.5 km grid spacing of the model, are identified using the very low Outgoing Longwave Radiation of their cold cloud tops. The water vapor budget reveals that the vertical transport, the sublimation and the subgrid-scale transport at their top contribute together to 11% of the water vapor mass input into the TLS. convection; water vapor; budget; global storm-resolving model; ICON; stratosphere
Devi, Archana; Satheesh, Sreedharan K.Devi, A., S. K. Satheesh, 2022: Global maps of aerosol single scattering albedo using combined CERES-MODIS retrieval. Atmospheric Chemistry and Physics, 22(8), 5365-5376. doi: 10.5194/acp-22-5365-2022. Abstract. Single scattering albedo (SSA) is a leading contributor to the uncertainty in aerosol radiative impact assessments. Therefore accurate information on aerosol absorption is required on a global scale. In this study, we have applied a multi-satellite algorithm to retrieve SSA (550 nm) using the concept of critical optical depth. Global maps of SSA were generated following this approach using spatially and temporally collocated data from Clouds and the Earth's Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on board Terra and Aqua satellites. Limited comparisons against airborne observations over India and surrounding oceans were generally in agreement within ±0.03. Global mean SSA estimated over land and ocean is 0.93 and 0.97, respectively. Seasonal and spatial distribution of SSA over various regions are also presented. Sensitivity analysis to various parameters indicate a mean uncertainty around ±0.044 and shows maximum sensitivity to changes in surface albedo. The global maps of SSA, thus derived with improved accuracy, provide important input to climate models for assessing the climatic impact of aerosols on regional and global scales.
Diamond, Michael S.; Gristey, Jake J.; Kay, Jennifer E.; Feingold, GrahamDiamond, M. S., J. J. Gristey, J. E. Kay, G. Feingold, 2022: Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry. Communications Earth & Environment, 3(1), 1-10. doi: 10.1038/s43247-022-00546-y. A striking feature of the Earth system is that the Northern and Southern Hemispheres reflect identical amounts of sunlight. This hemispheric albedo symmetry comprises two asymmetries: The Northern Hemisphere is more reflective in clear skies, whereas the Southern Hemisphere is cloudier. Here we show that the hemispheric reflection contrast from differences in continental coverage is offset by greater reflection from the Antarctic than the Arctic, allowing the net clear-sky asymmetry to be dominated by aerosol. Climate model simulations suggest that historical anthropogenic aerosol emissions drove a large increase in the clear-sky asymmetry that would reverse in future low-emission scenarios. High-emission scenarios also show decreasing asymmetry, instead driven by declines in Northern Hemisphere ice and snow cover. Strong clear-sky hemispheric albedo asymmetry is therefore a transient feature of Earth’s climate. If all-sky symmetry is maintained, compensating cloud changes would have uncertain but important implications for Earth’s energy balance and hydrological cycle. Atmospheric chemistry; Climate and Earth system modelling; Cryospheric science
Dodson, J. Brant; Robles, Marilé Colón; Rogerson, Tina M.; Taylor, Jessica E.Dodson, J. B., M. Robles, . Colón, T. M. Rogerson, J. E. Taylor, 2022: Do citizen science Intense Observation Periods increase data usability? A deep dive of the NASA GLOBE Clouds data set with satellite comparisons. Earth and Space Science, n/a(n/a), e2021EA002058. doi: 10.1029/2021EA002058. The Global Learning and Observations to Benefit the Environment (GLOBE) citizen science program has recently conducted a series of month-long intensive observation periods (IOPs), asking the public to submit daily reports on cloud and sky conditions from all regions of Earth. This provides a wealth of crowdsourced observations from the ground, which complements other conventional scientific cloud data. In addition, the GLOBE reports are matched in space and time with geostationary and low Earth orbit satellites, which allows for a straightforward comparison of cloud properties, and minimizes the biases associated with mismatched sampling between participants and satellites. The matched GLOBE dataset is used to calculate the mean observed cloud cover by atmospheric level both worldwide and by region. The overall magnitudes of cloud cover between the GLOBE participants and the matched satellites agree within 10%, which is notable given the distinctly different natures of the data sources. The mean vertical cloud profiles show GLOBE reporting more low-level clouds and fewer high-level clouds than satellites. The low cloud disagreement is likely related to satellites missing low clouds when high clouds block their view. Conversely, the high cloud disagreement is related primarily to cloud opacity, as satellites may miss some optically thin clouds. Monte Carlo testing shows the results to be robust, and the tripled amount of IOP data reduces uncertainty by half. These findings also highlight ways in which citizen science IOP data may be used to support scientific research while accounting for their unique properties. Monte Carlo; cloud cover; citizen science; global data set; satellite validation; vertical cloud structure
Espinoza, Jhan-Carlo; Marengo, José Antonio; Schongart, Jochen; Jimenez, Juan CarlosEspinoza, J., J. Marengo, . Antonio, J. Schongart, J. C. Jimenez, 2022: The new historical flood of 2021 in the Amazon River compared to major floods of the 21st century: Atmospheric features in the context of the intensification of floods. Weather and Climate Extremes, 35, 100406. doi: 10.1016/j.wace.2021.100406. In June 2021 a new extreme flood was reported in the Amazon Basin, the largest hydrological system on Earth. During this event water level was above 29 m (the emergency threshold) for 91 days at Manaus station (Brazil), surpassing even the previous historical flood of 2012. Since the late 1990s, 9 extreme floods occurred, while only 8 events were reported from 1903 to 1998. Here we report that the 2021 flood is associated with an intensification of the atmospheric upward motion in the northern Amazonia (5°S-5°N), which is related to an intensification of the Walker circulations. This atmospheric feature is associated with an enhanced of deep convective clouds and intense rainfall over the northern Amazonia that produce positive anomalies of terrestrial water storage over northern Amazonia in the 2021 austral summer. The intensification of Walker circulation is associated with La Niña conditions that characterize the major floods observed in Amazonia during the 21st century (2009, 2012 and 2021). However, during the 2021 an intensification of the continental Hadley circulation is also observed. This feature produces simultaneous dry conditions over southern and southeastern Amazonia, where negative rainfall anomalies, low frequency of deep convective clouds and negative anomalies of terrestrial water storage are observed.
Fasullo, J. T.; Lamarque, Jean-Francois; Hannay, Cecile; Rosenbloom, Nan; Tilmes, Simone; DeRepentigny, Patricia; Jahn, Alexandra; Deser, ClaraFasullo, J. T., J. Lamarque, C. Hannay, N. Rosenbloom, S. Tilmes, P. DeRepentigny, A. Jahn, C. Deser, 2022: Spurious Late Historical-Era Warming in CESM2 Driven by Prescribed Biomass Burning Emissions. Geophysical Research Letters, 49(2), e2021GL097420. doi: 10.1029/2021GL097420. A spurious increase in the interannual variability of prescribed biomass burning (BB) emissions in the CMIP6 forcing database during the satellite era of wildfire monitoring (1997–2014) is found to lead to warming in the Northern Hemisphere extratropics in simulations with the Community Earth System Model version 2 (CESM2). Using targeted sensitivity experiments with the CESM2 in which prescribed BB emissions are homogenized and variability is removed, we show that the warming is specifically attributable to BB variability from 40° to 70°N and arises from a net thinning of the cloud field and an associated increase in absorbed solar radiation. Our results also demonstrate the potential pitfalls of introducing discontinuities in climate forcing data sets when trying to incorporate novel observations. land/atmosphere interactions; aerosol/cloud interactions; global climate models; global change
Feng, Chunjie; Zhang, Xiaotong; Xu, Jiawen; Yang, Shuyue; Guan, Shikang; Jia, Kun; Yao, YunjunFeng, C., X. Zhang, J. Xu, S. Yang, S. Guan, K. Jia, Y. Yao, 2022: Comprehensive assessment of global atmospheric downward longwave radiation in the state-of-the-art reanalysis using satellite and flux tower observations. Climate Dynamics. doi: 10.1007/s00382-022-06366-2. The atmospheric downward longwave radiation at the Earth’s surface (Ld) is an important parameter for investigating greenhouse effects and global climate changes. Reanalysis data have been widely applied to obtain surface radiation components. Since new generation reanalysis data have been released, a comprehensive evaluation of the Ld predictions from the latest reanalysis data using ground measurements is still necessary. In this study, the Ld estimates of four representative reanalysis data (CFSR, JRA-55, ERA5, and MERRA2) were evaluated using ground observations at 383 stations from the AmeriFlux, AsiaFlux, BSRN, Buoy, FLUXNET, and SURFEAD networks. The evaluation results manifested that the overall root mean square errors (mean bias errors) of daily mean Ld values over the global surface were 21.1 (− 1.8) W m−2, 22.4 (− 3.9) W m−2, 19.3 (− 3.6) W m−2, 25.2 (− 12.6) W m−2, and 20.5 (3.1) W m−2 for CFSR, JRA-55, ERA5, MERAA2, and CERES-SYN, respectively. Compared with the CERES-SYN satellite retrievals, the ERA5 (CFSR) daily mean Ld estimates had relatively smaller overall root mean square errors (mean bias errors) over the global land surface. Over the global ocean surface, the JRA-55 daily mean Ld estimates had comparable mean bias errors (MBEs) with CERES-SYN. After removing the MBEs, the best annual mean Ld estimate was 344.0 (± 3) W m−2 over the global surface of 2001 to 2020. The spatial distributions and long-term trends of Ld for the selected four reanalysis data and CERES-SYN were also investigated in this study. The comprehensive assessment of the Ld products from reanalysis data and satellite retrievals in this study would be helpful for climate change studies. Reanalysis; Surface downward longwave radiation; CERES-SYN; Ground observation
Ferris, Laur; Gong, Donglai; Clayson, Carol Anne; Merrifield, Sophia; Shroyer, Emily L.; Smith, Madison; Laurent, Louis StFerris, L., D. Gong, C. A. Clayson, S. Merrifield, E. L. Shroyer, M. Smith, L. S. Laurent, 2022: Shear Turbulence in the High-Wind Southern Ocean Using Direct Measurements. J. Phys. Oceanogr., 52(10), 2325-2341. doi: 10.1175/JPO-D-21-0015.1. Abstract The ocean surface boundary layer is a gateway of energy transfer into the ocean. Wind-driven shear and meteorologically forced convection inject turbulent kinetic energy into the surface boundary layer, mixing the upper ocean and transforming its density structure. In the absence of direct observations or the capability to resolve subgrid-scale 3D turbulence in operational ocean models, the oceanography community relies on surface boundary layer similarity scalings (BLS) of shear and convective turbulence to represent this mixing. Despite their importance, near-surface mixing processes (and ubiquitous BLS representations of these processes) have been undersampled in high-energy forcing regimes such as the Southern Ocean. With the maturing of autonomous sampling platforms, there is now an opportunity to collect high-resolution spatial and temporal measurements in the full range of forcing conditions. Here, we characterize near-surface turbulence under strong wind forcing using the first long-duration glider microstructure survey of the Southern Ocean. We leverage these data to show that the measured turbulence is significantly higher than standard shear-convective BLS in the shallower parts of the surface boundary layer and lower than standard shear-convective BLS in the deeper parts of the surface boundary layer; the latter of which is not easily explained by present wave-effect literature. Consistent with the CBLAST (Coupled Boundary Layers and Air Sea Transfer) low winds experiment, this bias has the largest magnitude and spread in the shallowest 10% of the actively mixing layer under low-wind and breaking wave conditions, when relatively low levels of turbulent kinetic energy (TKE) in surface regime are easily biased by wave events. Significance Statement Wind blows across the ocean, turbulently mixing the water close to the surface and altering its properties. Without the ability to measure turbulence in remote locations, oceanographers use approximations called boundary layer scalings (BLS) to estimate the amount of turbulence caused by the wind. We compared turbulence measured by an underwater robot to turbulence estimated from wind speed to determine how well BLS performs in stormy places. We found that in both calm and stormy conditions, estimates are 10 times too large closest to the surface and 10 times too small deeper within the turbulently mixed surface ocean.
Francis, Diana; Fonseca, Ricardo; Nelli, Narendra; Bozkurt, Deniz; Picard, Ghislain; Guan, BinFrancis, D., R. Fonseca, N. Nelli, D. Bozkurt, G. Picard, B. Guan, 2022: Atmospheric rivers drive exceptional Saharan dust transport towards Europe. Atmospheric Research, 266, 105959. doi: 10.1016/j.atmosres.2021.105959. This study highlights the occurrence of atmospheric rivers (ARs) over northwest Africa towards Europe, which were accompanied by intense episodes of Saharan dust transport all the way to Scandinavia, in the winter season. Using a combination of observational and reanalysis data, we investigate two extreme dusty AR events in February 2021 and assess their impact on snow melt in the Alps. The warm, moist, and dusty air mass (spatially-averaged 2-meter temperature and water vapour mixing ratio anomalies of up to 8 K and 3 g kg−1, and aerosol optical depths and dust loadings of up to 0.85 and 11 g m−2, respectively) led to a 50% and 40% decrease in snow depth and surface albedo, respectively, in less than one month during the winter season. ARs over northwest Africa show increasing trends over the past 4 decades, with 78% of AR events associated with severe dust episodes over Europe. Dust aerosols; Atmospheric rivers; European Alps; Sahara Desert; Snow melting; Water vapour
Francis, Diana; Fonseca, Ricardo; Nelli, Narendra; Teixido, Oriol; Mohamed, Ruqaya; Perry, RichardFrancis, D., R. Fonseca, N. Nelli, O. Teixido, R. Mohamed, R. Perry, 2022: Increased Shamal winds and dust activity over the Arabian Peninsula during the COVID-19 lockdown period in 2020. Aeolian Research, 55, 100786. doi: 10.1016/j.aeolia.2022.100786. While anthropogenic pollutants have decreased during the lockdown imposed as an effort to contain the spread of the Coronavirus disease 2019 (COVID-19), changes in particulate matter (PM) do not necessarily exhibit the same tendency. This is the case for the eastern Arabian Peninsula, where in March–June 2020, and with respect to the same period in 2016–2019, a 30 % increase in PM concentration is observed. A stronger than normal nocturnal low-level jet and subtropical jet over parts of Saudi Arabia, in response to anomalous convection over the tropical Indian Ocean, promoted enhanced and more frequent episodes of Shamal winds over the Arabian Peninsula. Increased surface winds associated with the downward mixing of momentum to the surface fostered, in turn, dust lifting and increased PM concentrations. The stronger low-level winds also favoured long-range transport of aerosols, changing the PM values downstream. The competing effects of reduced anthropogenic and increased dust concentrations leave a small positive signal (20 W m−2 with respect to the baseline period, owing to a clearer environment and weaker winds. It is concluded that a reduction in anthropogenic emissions due to the lockdown does not necessarily go hand in hand with lower particulate matter concentrations. Therefore, emissions reduction strategies need to account for feedback effects in order to reach the planned long-term outcomes. Arabian Peninsula; Low-level jet; Particulate Matter; Rossby Wavetrain; Shamal Winds; Surface Radiation Budget
Francis, Diana; Nelli, Narendra; Fonseca, Ricardo; Weston, Michael; Flamant, Cyrille; Cherif, CharfeddineFrancis, D., N. Nelli, R. Fonseca, M. Weston, C. Flamant, C. Cherif, 2022: The dust load and radiative impact associated with the June 2020 historical Saharan dust storm. Atmospheric Environment, 268, 118808. doi: 10.1016/j.atmosenv.2021.118808. In June 2020, a major dust outbreak occurred in the Sahara that impacted the tropical Atlantic Ocean. In this study, the dust load and radiative forcing of the dust plumes on both the atmosphere and ocean surface is investigated by means of observations and modelling. We estimated dust loadings in excess of 8 Tg over the eastern tropical Atlantic, comparable to those observed over the desert during major Saharan dust storms. The dust induced an up to 1.1 K net warming of the ocean surface and a 1.8K warming of the air temperature (i.e., two to three times the respective climatological standard deviations), with a +14 W m−2 (∼28% of the mean value) increase in the surface net radiation flux at night. As the dust plumes extended all the way to the Caribbean, it is possible that this historical dust event helped fuel the record-breaking 2020 Atlantic hurricane season. Dust aerosols; Radiative forcing; WRF-Chem; Sahara; Tropical Atlantic
Giraldo, Jorge A.; del Valle, Jorge I.; González-Caro, Sebastián; Sierra, Carlos A.Giraldo, J. A., J. I. del Valle, S. González-Caro, C. A. Sierra, 2022: Intra-annual isotope variations in tree rings reveal growth rhythms within the least rainy season of an ever-wet tropical forest. Trees, 36(3), 1039-1052. doi: 10.1007/s00468-022-02271-7. Isotope variation (δ18O) in wood suggests new insights on growth rhythms in trees growing in tropical forest with extremely high precipitation, without seasonal droughts or flooding. Biogeographical Chocó region; C isotopes; Dendrochronology; O isotopes; Tropical trees
González-Bárcena, David; Bermejo-Ballesteros, Juan; Pérez-Grande, Isabel; Sanz-Andrés, ÁngelGonzález-Bárcena, D., J. Bermejo-Ballesteros, I. Pérez-Grande, Á. Sanz-Andrés, 2022: Selection of time-dependent worst-case thermal environmental conditions for Low Earth Orbit spacecrafts. Advances in Space Research, 70(7), 1847-1868. doi: 10.1016/j.asr.2022.06.060. When facing the thermal analysis of a Low Earth Orbit satellite, selecting the worst-case orbit where the minimum and maximum temperatures are reached is essential for ensuring the success of the mission. Typical orbits have a non-constant Solar Beta Angle throughout the year providing a wide range of orbits with different heat loads and eclipses. It is possible to focus the analysis on a single orbit configuration by a rough analysis using a simple model. In order to achieve this, every potential orbit with their corresponding thermal environmental parameters must be analysed based on real data. The direct solar radiation, the albedo and the Earth Outgoing Longwave Radiation (OLR) characterize the thermal environment to be taken into account. However, their values have a wide variability which depend on many parameters. Based on the characteristics of the orbit and the system thermo-optical properties and characteristic time, it is possible to obtain particularized profiles of albedo and OLR that would lead the system to its maximum and minimum temperatures. The conventional criteria, which is studied here in depth, provides two constant values of albedo and OLR as the hot and cold worst-cases. This is suitable for massive system or cases in which the characteristics times of the system are high. For lighter elements or low characteristic times, temperatures throughout the orbit deviate considerably from the real behaviour. In contrast, the methodology here proposed provides a time-dependant profile that allows for the determination of a system temperature response closer to the real one, together with the potential minimum and maximum temperatures of the orbit, in order to optimize the design and avoid the oversizing. Albedo; Thermal environment; OLR; LEO; Thermal analysis; Worst-case
Haghighatnasab, Mahnoosh; Kretzschmar, Jan; Block, Karoline; Quaas, JohannesHaghighatnasab, M., J. Kretzschmar, K. Block, J. Quaas, 2022: Impact of Holuhraun volcano aerosols on clouds in cloud-system-resolving simulations. Atmospheric Chemistry and Physics, 22(13), 8457-8472. doi: 10.5194/acp-22-8457-2022. Abstract. Increased anthropogenic aerosols result in an enhancement in cloud droplet number concentration (Nd), which consequently modifies the cloud and precipitation process. It is unclear how exactly the cloud liquid water path (LWP) and cloud fraction respond to aerosol perturbations. A volcanic eruption may help to better understand and quantify the cloud response to external perturbations, with a focus on the short-term cloud adjustments. The goal of the present study is to understand and quantify the response of clouds to a selected volcanic eruption and to thereby advance the fundamental understanding of the cloud response to external forcing. In this study we used the ICON (ICOsahedral Non-hydrostatic) model in its numerical weather prediction setup at a cloud-system-resolving resolution of 2.5 km horizontally, to simulate the region around the Holuhraun volcano for 1 week (1–7 September 2014). A pair of simulations, with and without the volcanic aerosol plume, allowed us to assess the simulated effective radiative forcing and its mechanisms, as well as its impact on adjustments of LWP and cloud fraction to the perturbations of Nd. In comparison to MODIS (Moderate Resolution Imaging Spectroradiometer) satellite retrievals, a clear enhancement of Nd due to the volcanic aerosol is detected and attributed. In contrast, no changes in either LWP or cloud fraction could be attributed. The on average almost unchanged LWP is a result of some LWP enhancement for thick clouds and a decrease for thin clouds.
Ham, Seung-Hee; Kato, Seiji; Rose, Fred G.; Sun-Mack, Sunny; Chen, Yan; Miller, Walter F.; Scott, Ryan C.Ham, S., S. Kato, F. G. Rose, S. Sun-Mack, Y. Chen, W. F. Miller, R. C. Scott, 2022: Combining Cloud Properties from CALIPSO, CloudSat, and MODIS for Top-of-Atmosphere (TOA) Shortwave Broadband Irradiance Computations: Impact of Cloud Vertical Profiles. J. Appl. Meteor. Climatol., 61(10), 1449-1471. doi: 10.1175/JAMC-D-21-0260.1. Abstract Cloud vertical profile measurements from the CALIPSO and CloudSat active sensors are used to improve top-of-atmosphere (TOA) shortwave (SW) broadband (BB) irradiance computations. The active sensor measurements, which occasionally miss parts of the cloud columns because of the full attenuation of sensor signals, surface clutter, or insensitivity to a certain range of cloud particle sizes, are adjusted using column-integrated cloud optical depth derived from the passive MODIS sensor. Specifically, we consider two steps in generating cloud profiles from multiple sensors for irradiance computations. First, cloud extinction coefficient and cloud effective radius (CER) profiles are merged using available active and passive measurements. Second, the merged cloud extinction profiles are constrained by the MODIS visible scaled cloud optical depth, defined as a visible cloud optical depth multiplied by (1 − asymmetry parameter), to compensate for missing cloud parts by active sensors. It is shown that the multisensor-combined cloud profiles significantly reduce positive TOA SW BB biases, relative to those with MODIS-derived cloud properties only. The improvement is more pronounced for optically thick clouds, where MODIS ice CER is largely underestimated. Within the SW BB (0.18–4 μm), the 1.04–1.90-μm spectral region is mainly affected by the CER, where both the cloud absorption and solar incoming irradiance are considerable. Significance Statement The purpose of this study is to improve shortwave irradiance computations at the top of the atmosphere by using combined cloud properties from active and passive sensor measurements. Relative to the simulation results with passive sensor cloud measurements only, the combined cloud profiles provide more accurate shortwave simulation results. This is achieved by more realistic profiles of cloud extinction coefficient and cloud particle effective radius. The benefit is pronounced for optically thick clouds composed of large ice particles.
Hartmann, Dennis L.; Dygert, Brittany D.Hartmann, D. L., B. D. Dygert, 2022: Global Radiative Convective Equilibrium With a Slab Ocean: SST Contrast, Sensitivity and Circulation. Journal of Geophysical Research: Atmospheres, 127(12), e2021JD036400. doi: 10.1029/2021JD036400. Warming experiments with a uniformly insolated, non-rotating climate model with a slab ocean are conducted by increasing the solar irradiance. As the global mean surface temperature is varied across the range from 289 to 319K, the sea surface temperature (SST) contrast at first declines, then increases then declines again. Increasing SST contrast with global warming is associated with reduced climate sensitivity, while decreasing SST contrast is associated with enhanced climate sensitivity. The changing SST contrast and climate sensitivity are both related fundamentally to the effect of water vapor on clear-sky radiative cooling. The clouds in the convective region are always more reflective than those in the subsiding region and so always act to reduce the SST contrast. At lower temperatures between 289 and 297 K the shortwave suppression of SST contrast increases faster than the longwave enhancement of SST contrast. At warmer temperatures between 297 and 309 K the longwave enhancement of SST contrast with warming is stronger than the shortwave suppression of SST contrast, so that the SST contrast increases. Above 309 K the greenhouse effect in the subsiding region begins to grow, the SST contrast declines and the climate sensitivity increases. The transitions at 297 and 309 K can be related to the increasing vapor pressure path with warming. The mass circulation rate between warm and cool regions consists of shallow and deep cells. Both cells increase in strength with SST contrast. The lower cell remains connected to the surface, while the upper cell rises to maintain a roughly constant temperature. climate change; climate model; climate feedbacks
Heidinger, Andrew K.; Foster, Michael J.; Knapp, Kenneth R.; Schmit, Timothy J.Heidinger, A. K., M. J. Foster, K. R. Knapp, T. J. Schmit, 2022: Using GOES-R ABI Full-Disk Reflectance as a Calibration Source for the GOES Imager Visible Channels. Remote Sensing, 14(15), 3630. doi: 10.3390/rs14153630. The availability of onboard calibration for solar reflectance channels on recently launched advanced geostationary imagers provides an opportunity to revisit the calibration of the visible channels on past geostationary imagers, which lacked onboard calibration systems. This study used the data from the Advanced Baseline Imager (ABI) on GOES-16 and GOES-17 to calibrate the visible channels on the GOES-IP (GOES-8, -9, -10, -11, -12, -13, and -15) sensors (1994–2021). The visible channels are dominant sources of information for many of the essential climate variables from these sensors. The technique developed uses the stability of the integrated full-disk reflectance to define a calibration target that is applied to past sensors to generate new calibration equations. These equations are found to be stable and agree well with other established techniques. Given the lack of assumptions and ease of application, this technique offers a new calibration method that can be used to complement existing techniques used by the operational space agencies with the GSICS Project. In addition, its simplicity allows for its application to data that existed prior to many of the reference data employed in current calibration methods. calibration; climate; GOES
Herrington, Adam R.; Lauritzen, Peter H.; Lofverstrom, Marcus; Lipscomb, William H.; Gettelman, Andrew; Taylor, Mark A.Herrington, A. R., P. H. Lauritzen, M. Lofverstrom, W. H. Lipscomb, A. Gettelman, M. A. Taylor, 2022: Impact of grids and dynamical cores in CESM2.2 on the surface mass balance of the Greenland Ice Sheet. Journal of Advances in Modeling Earth Systems, n/a(n/a), e2022MS003192. doi: 10.1029/2022MS003192. Six different configurations, a mixture of grids and atmospheric dynamical cores available in the Community Earth System Model, version 2.2 (CESM2.2), are evaluated for their skill in representing the climate of the Arctic and the surface mass balance of the Greenland Ice Sheet (GrIS). The finite-volume dynamical core uses structured, latitude-longitude grids, whereas the spectral-element dynamical core is built on unstructured meshes, permitting grid flexibility such as quasi-uniform grid spacing globally. The 1° − 2° latitude-longitude and quasi-uniform unstructured grids systematically overestimate both accumulation and ablation over the GrIS. Of these 1° − 2° grids, the latitude-longitude grids outperform the quasi-uniform unstructured grids because they have more degrees of freedom to represent the GrIS. Two Arctic-refined meshes, with 1/4° and 1/8° refinement over Greenland, were developed for the spectral-element dynamical core and are documented here as newly supported configurations in CESM2.2. The Arctic meshes substantially improve the simulated clouds and precipitation rates in the Arctic. Over Greenland, these meshes skillfully represent accumulation and ablation processes, leading to a more realistic GrIS surface mass balance. As CESM is in the process of transitioning away from conventional latitude-longitude grids, these new Arctic-refined meshes improve the representation of polar processes in CESM by recovering resolution lost in the transition to quasi-uniform grids, albeit at increased computational cost.
Hu, Zhiyuan; Jin, Qinjian; Ma, Yuanyuan; Ji, Zhenming; Zhu, Xian; Dong, WenjieHu, Z., Q. Jin, Y. Ma, Z. Ji, X. Zhu, W. Dong, 2022: How Does COVID-19 Lockdown Impact Air Quality in India?. Remote Sensing, 14(8), 1869. doi: 10.3390/rs14081869. Air pollution is a severe environmental problem in the Indian subcontinent. Largely caused by the rapid growth of the population, industrialization, and urbanization, air pollution can adversely affect human health and environment. To mitigate such adverse impacts, the Indian government launched the National Clean Air Programme (NCAP) in January 2019. Meanwhile, the unexpected city-lockdown due to the COVID-19 pandemic in March 2020 in India greatly reduced human activities and thus anthropogenic emissions of gaseous and aerosol pollutants. The NCAP and the lockdown could provide an ideal field experiment for quantifying the extent to which various levels of human activity reduction impact air quality in the Indian subcontinent. Here, we study the improvement in air quality due to COVID-19 and the NCAP in the India subcontinent by employing multiple satellite products and surface observations. Satellite data shows significant reductions in nitrogen dioxide (NO2) by 17% and aerosol optical depth (AOD) by 20% during the 2020 lockdown with reference to the mean levels between 2005–2019. No persistent reduction in NO2 nor AOD is detectable during the NCAP period (2019). Surface observations show consistent reductions in PM2.5 and NO2 during the 2020 lockdown in seven cities across the Indian subcontinent, except Mumbai in Central India. The increase in relative humidity and the decrease in the planetary boundary layer also play an important role in influencing air quality during the 2020 lockdown. With the decrease in aerosols during the lockdown, net radiation fluxes show positive anomalies at the surface and negative anomalies at the top of the atmosphere over most parts of the Indian subcontinent. The results of this study could provide valuable information for policymakers in South Asia to adjust the scientific measures proposed in the NCAP for efficient air pollution mitigation. AOD; air quality; COVID-19; India subcontinent; NO2; PM2.5
Ito, Masato; Masunaga, HirohikoIto, M., H. Masunaga, 2022: Process-level Assessment of the Iris Effect over Tropical Oceans. Geophysical Research Letters, n/a(n/a), e2022GL097997. doi: 10.1029/2022GL097997. The iris hypothesis suggests a cloud feedback mechanism that a reduction in the tropical anvil cloud fraction (CF) in a warmer climate may act to mitigate the warming by enhanced outgoing longwave radiation. Two different physical processes, one involving precipitation efficiency and the other focusing on upper-tropospheric stability, have been argued in the literature to be responsible for the iris effect. In this study, A-Train observations and reanalysis data are analyzed to assess these two processes. Major findings are as follows: (1) the anvil CF changes evidently with upper-tropospheric stability as expected from the stability iris theory, (2) precipitation efficiency is unlikely to have control on the anvil CF but is related to mid- and low-level CFs, and (3) the day and nighttime cloud radiative effects are expected to largely cancel out when integrated over a diurnal cycle, suggesting a neutral cloud feedback.
Jia, Aolin; Wang, Dongdong; Liang, Shunlin; Peng, Jingjing; Yu, YunyueJia, A., D. Wang, S. Liang, J. Peng, Y. Yu, 2022: Global daily actual and snow-free blue-sky land surface albedo climatology from 20-year MODIS products. Journal of Geophysical Research: Atmospheres, n/a(n/a), e2021JD035987. doi: 10.1029/2021JD035987. Land surface albedo plays a critical role in climate, hydrological and biogeochemical modeling, and weather forecasting. It is often assigned in models and satellite retrievals by albedo climatology look-up tables using land cover type and other variables; however, there are considerable differences in albedo simulations among models, which partially result from uncertainty in obsolete albedo climatology. Therefore, this study introduces a new global 500 m daily blue-sky land surface albedo climatology dataset under both actual and snow-free surface conditions utilizing 20-year Moderate Resolution Imaging Spectroradiometer (MODIS) products from Google Earth Engine. In situ measurements from 38 long-term-maintained sites were utilized to validate the accuracies of different albedo climatology datasets. The root-mean-square error, bias, and correlation coefficient of the new climatology are 0.031, -0.003, and 0.96, respectively, which are more accurate than the GLASS, GlobAlbedo, and 16 model datasets. Data intercomparison suggests that ERA5 exhibits better performance than MERRA2 and 14 CMIP6 models. However, it contains positive biases in the snow-free season, while MERRA2 underestimates the snow albedo. Global albedo variation associated with basic surface plant functional types was also characterized, and snow impact was considered separately. Temporal variability analysis indicates that traditional climatology datasets with coarser temporal resolutions (≥8 days) cannot capture albedo variation over areas with distinct snow seasons, especially in central Eurasia and boreal regions. These results confirm the high reliability and robustness of the new albedo climatology in model assessment, data assimilation, and satellite product retrievals. MODIS; satellite retrieval; climatology; land surface albedo; model assessment
Jiang, Shuyi; Zhao, Chuanfeng; Xia, YanJiang, S., C. Zhao, Y. Xia, 2022: Distinct response of near surface air temperature to clouds in North China. Atmospheric Science Letters, n/a(n/a), e1128. doi: 10.1002/asl.1128. Using the daily 2 m maximum temperature (Tmax), 2 m minimum temperature (Tmin) and cloud cover data measured at ground sites of the China Meteorological Administration in North China from 2000 to 2017, this study investigates the influence of clouds on the daily temperature range (DTR) defined as the difference between Tmax and Tmin. As expected, the cloud cover shows the similar averaged spatial distribution and monthly variation with Tmin. Surprisingly, it also shows the similar average spatial distribution and monthly variation with Tmax, suggesting the more important roles of regions (latitude) and seasons associated with the variations of land surface temperature, which is further related to solar radiation absorbed and surface heat capacity. By comparing monthly variations of temperature between cloudy and clear skies, we find that clouds can weaken Tmax and increase Tmin, and thus decrease DTR. As a result, the spatial distribution of DTR is opposite to the cloud cover. The clouds have relatively stronger impact on Tmin and DTR over mountain region, which is most likely caused by the stronger longwave cloud radiative forcing associated with higher cloud tops over the mountain region. cloud cover; cloud top; daily temperature range; spatial distribution; temporal variation
Jiao, Zhong-Hu; Mu, XihanJiao, Z., X. Mu, 2022: Single-footprint retrieval of clear-sky surface longwave radiation from hyperspectral AIRS data. International Journal of Applied Earth Observation and Geoinformation, 110, 102802. doi: 10.1016/j.jag.2022.102802. Surface longwave radiation (SLR) derived from remotely sensed data facilitates understanding of the SLR in global climate change. Hyperspectral infrared sounders aboard space platforms provide information on the surface and vertical structure of Earth’s atmosphere. However, currently, SLR products estimated from these observations are unavailable, which hampers their application potential for Earth’s radiation budget in the context of global warming. To address this issue, we developed simple and effective SLR model under clear-sky conditions using at-sensor spectral radiances from Atmospheric Infrared Sounder (AIRS). The model was found to be insensitive to AIRS instrument noise, and showed good performances based on a simulation dataset. The AIRS footprint geometrical model was proposed to match the AIRS and Moderate Resolution Imaging Spectroradiometer (MODIS) data to estimate the cloud fraction. Validation against ground-based measurements found that the surface upward longwave radiation model has a bias of 3.18 W/m2, root-mean-square error (RMSE) of 30.51 W/m2, and R2 of 0.84; the surface downward longwave radiation model has a bias of 0.77 W/m2, RMSE of 29.09 W/m2, and R2 of 0.78. The large validation biases at two ground sites reflect the limited spatial representativeness for AIRS footprints. Terrain-induced altitude differences and spatial inhomogeneity can redistribute the spatial distributions of SLR. Moreover, the model performances were weakly dependent on seasonal variation. The results indicate that the proposed model provides a foundation for the further development of operational SLR products. Surface radiation budget; Atmospheric Infrared Sounder (AIRS); Hybrid method; Hyperspectral infrared remote sensing; Spatial representativeness; Surface longwave radiation
Jin, Daeho; Oreopoulos, Lazaros; Lee, Dongmin; Tan, Jackson; Kim, Kyu-myongJin, D., L. Oreopoulos, D. Lee, J. Tan, K. Kim, 2022: A New Organization Metric for Synoptic Scale Tropical Convective Aggregation. Journal of Geophysical Research: Atmospheres, 127(13), e2022JD036665. doi: 10.1029/2022JD036665. Organization metrics were originally developed to measure how densely convective clouds are arranged at mesoscales. In this work, we apply organization metrics to describe tropical synoptic scale convective activity. Such activity is identified by cloud-precipitation (hybrid) regimes defined at 1-degree and 1-hourly resolution. Existing metrics were found to perform inadequately for such convective regime aggregates because the large domain size and co-existence of sparse aggregate occurrences with noisy isolated convection often violate assumptions inherent in these metrics. In order to capture these characteristics, in this study the existing “convective organization potential” (COP) metric was modified so as to focus on local organization and provide increased weight to aggregate size. The resulting “area-based COP” (ABCOP) follows the principle that the more numerous the objects, the higher the chance of organization. It is thus optimized to capture large-scale convective events occurring during phenomena such as ENSO and MJO, while also performs as well as existing metrics for small domain sizes. tropical convection; cloud-precipitation regime; organization metric
Jönsson, Aiden; Bender, Frida A.-M.Jönsson, A., F. A. Bender, 2022: Corrigendum. J. Climate, 35(15), 5233-5234. doi: 10.1175/JCLI-D-22-0128.1. "Corrigendum" published on 01 Aug 2022 by American Meteorological Society.
Jönsson, Aiden; Bender, Frida A.-M.Jönsson, A., F. A. Bender, 2022: Persistence and Variability of Earth’s Interhemispheric Albedo Symmetry in 19 Years of CERES EBAF Observations. J. Climate, 35(1), 249-268. doi: 10.1175/JCLI-D-20-0970.1. Abstract Despite the unequal partitioning of land and aerosol sources between the hemispheres, Earth’s albedo is observed to be persistently symmetric about the equator. This symmetry is determined by the compensation of clouds to the clear-sky albedo. Here, the variability of this interhemispheric albedo symmetry is explored by decomposing observed radiative fluxes in the CERES EBAF satellite data record into components reflected by the atmosphere, clouds, and the surface. We find that the degree of interhemispheric albedo symmetry has not changed significantly throughout the observational record. The variability of the interhemispheric difference in reflected solar radiation (asymmetry) is strongly determined by tropical and subtropical cloud cover, particularly those related to nonneutral phases of El Niño–Southern Oscillation (ENSO). As ENSO is the most significant source of interannual variability in reflected radiation on a global scale, this underscores the interhemispheric albedo symmetry as a robust feature of Earth’s current annual mean climate. Comparing this feature in observations with simulations from coupled models reveals that the degree of modeled albedo symmetry is mostly dependent on biases in reflected radiation in the midlatitudes, and that models that overestimate its variability the most have larger biases in reflected radiation in the tropics. The degree of model albedo symmetry is improved when driven with historical sea surface temperatures, indicating that the degree of symmetry in Earth’s albedo is dependent on the representation of cloud responses to coupled ocean–atmosphere processes.
Jungclaus, J.h.; Lorenz, S.j.; Schmidt, H.; Brovkin, V.; Brüggemann, N.; Chegini, F.; Crüger, T.; De-Vrese, P.; Gayler, V.; Giorgetta, M.a; Gutjahr, O.; Haak, H.; Hagemann, S.; Hanke, M.; Ilyina, T.; Korn, P.; Kröger, J.; Linardakis, L.; Mehlmann, C.; Mikolajewicz, U.; Müller, W.a.; Nabel, J.e.m.s; Notz, D.; Pohlmann, H.; Putrasahan, D.a.; Raddatz, T.; Ramme, L.; Redler, R.; Reick, C.h.; Riddick, T.; Sam, T.; Schneck, R.; Schnur, R.; Schupfner, M.; Storch, J.-S. von; Wachsmann, F.; Wieners, K.-H.; Ziemen, F.; Stevens, B.; Marotzke, J.; Claussen, M.Jungclaus, J., S. Lorenz, H. Schmidt, V. Brovkin, N. Brüggemann, F. Chegini, T. Crüger, P. De-Vrese, V. Gayler, M. Giorgetta, O. Gutjahr, H. Haak, S. Hagemann, M. Hanke, T. Ilyina, P. Korn, J. Kröger, L. Linardakis, C. Mehlmann, U. Mikolajewicz, W. Müller, J. Nabel, D. Notz, H. Pohlmann, D. Putrasahan, T. Raddatz, L. Ramme, R. Redler, C. Reick, T. Riddick, T. Sam, R. Schneck, R. Schnur, M. Schupfner, J. v. Storch, F. Wachsmann, K. Wieners, F. Ziemen, B. Stevens, J. Marotzke, M. Claussen, 2022: The ICON Earth System Model Version 1.0. Journal of Advances in Modeling Earth Systems, n/a(n/a), e2021MS002813. doi: 10.1029/2021MS002813. This work documents the ICON-Earth System Model (ICON-ESM V1.0), the first coupled model based on the ICON (ICOsahedral Non-hydrostatic) framework with its unstructured, icosahedral grid concept. The ICON-A atmosphere uses a nonhydrostatic dynamical core and the ocean model ICON-O builds on the same ICON infrastructure, but applies the Boussinesq and hydrostatic approximation and includes a sea-ice model. The ICON-Land module provides a new framework for the modelling of land processes and the terrestrial carbon cycle. The oceanic carbon cycle and biogeochemistry are represented by the Hamburg Ocean Carbon Cycle module. We describe the tuning and spin-up of a base-line version at a resolution typical for models participating in the Coupled Model Intercomparison Project (CMIP). The performance of ICON-ESM is assessed by means of a set of standard CMIP6 simulations. Achievements are well-balanced top-of-atmosphere radiation, stable key climate quantities in the control simulation, and a good representation of the historical surface temperature evolution. The model has overall biases, which are comparable to those of other CMIP models, but ICON-ESM performs less well than its predecessor, the Max Planck Institute Earth System Model. Problematic biases are diagnosed in ICON-ESM in the vertical cloud distribution and the mean zonal wind field. In the ocean, sub-surface temperature and salinity biases are of concern as is a too strong seasonal cycle of the sea-ice cover in both hemispheres. ICON-ESM V1.0 serves as a basis for further developments that will take advantage of ICON-specific properties such as spatially varying resolution, and configurations at very high resolution. Earth; Model; System
Kenny, Darragh; Fiedler, StephanieKenny, D., S. Fiedler, 2022: Which gridded irradiance data is best for modelling photovoltaic power production in Germany?. Solar Energy, 232, 444-458. doi: 10.1016/j.solener.2021.12.044. Model estimates of expected photovoltaic (PV) power production rely on accurate irradiance data. Reanalysis and satellite products freely provide irradiance data with a high temporal and spatial resolution including locations for which no ground-based measurements are available. We assess differences in such gridded irradiance data and quantify the subsequent bias propagation from individual radiation components to capacity factors in a contemporary PV model. PV power production is simulated based on four reanalysis (ERA5, COSMO-REA6, COSMO-REA6pp, COSMO-REA2) and three satellite products (CAMS, SARAH-2, CERES Syn1Deg). The results are compared against simulations using measurements from 30 weather stations of the German Weather Service. We compute metrics characterizing biases in seasonal and annual means, day-to-day variability and extremes in PV power. Our results highlight a bias of −1.4% (COSMO-REA6) to ＋8.2% (ERA5) in annual and spatial means of PV power production for Germany. No single data set is best in all metrics, although SARAH-2 and the postprocessed COSMO-REA6 data (COSMO-REA6pp) outperform the other products for many metrics. SARAH-2 yields good results in summer, but overestimates PV output in winter by 16% averaged across all stations. COSMO-REA6pp represents day-to-day variability in the PV power production of a simulated PV fleet best and has a particularly small bias of 0.5% in annual means. This is at least in parts due to compensating biases in local and seasonal means. Our results imply that gridded irradiance data should be used with caution for site assessments and ideally be complemented by local measurements. Satellite; Data evaluation; Irradiance data; PV power model; Re-analysis; Station observations
Khairoutdinov, Marat F.; Blossey, Peter N.; Bretherton, Christopher S.Khairoutdinov, M. F., P. N. Blossey, C. S. Bretherton, 2022: Global System for Atmospheric Modeling: Model Description and Preliminary Results. Journal of Advances in Modeling Earth Systems, 14(6), e2021MS002968. doi: 10.1029/2021MS002968. The extension of a cloud-resolving model, the System for Atmospheric Modeling (SAM), to global domains is described. The resulting global model, gSAM, is formulated on a latitude-longitude grid. It uses an anelastic dynamical core with a single reference profile (as in SAM), but its governing equations differ somewhat from other anelastic models. For quasihydrostatic flows, they are isomorphic to the primitive equations (PE) in pressure coordinates but with the globally uniform reference pressure playing the role of actual pressure. As a result, gSAM can exactly maintain steady zonally symmetric baroclinic flows that have been specified in pressure coordinates, produces accurate simulations when initialized or nudged with global reanalyses, and has a natural energy conservation equation despite the drawbacks of using the anelastic system to model global scales. gSAM employs a novel treatment of topography using a type of immersed boundary method, the Quasi-Solid Body Method, where the instantaneous flow velocity is forced to stagnate in grid cells inside a prescribed terrain. The results of several standard tests designed to evaluate the accuracy of global models with and without topography as well as results from real Earth simulations are presented. global cloud-resolving model; model description; global storm-resolving model; anelastic dynamical core; system for atmospheric modeling
Knippertz, Peter; Gehne, Maria; Kiladis, George N.; Kikuchi, Kazuyoshi; Rasheeda Satheesh, Athul; Roundy, Paul E.; Yang, Gui-Ying; Žagar, Nedjeljka; Dias, Juliana; Fink, Andreas H.; Methven, John; Schlueter, Andreas; Sielmann, Frank; Wheeler, Matthew C.Knippertz, P., M. Gehne, G. N. Kiladis, K. Kikuchi, A. Rasheeda Satheesh, P. E. Roundy, G. Yang, N. Žagar, J. Dias, A. H. Fink, J. Methven, A. Schlueter, F. Sielmann, M. C. Wheeler, 2022: The intricacies of identifying equatorial waves. Quarterly Journal of the Royal Meteorological Society, 148(747), 2814-2852. doi: 10.1002/qj.4338. Equatorial waves (EWs) are synoptic- to planetary-scale propagating disturbances at low latitudes with periods from a few days to several weeks. Here, this term includes Kelvin waves, equatorial Rossby waves, mixed Rossby–gravity waves, and inertio-gravity waves, which are well described by linear wave theory, but it also other tropical disturbances such as easterly waves and the intraseasonal Madden–Julian Oscillation with more complex dynamics. EWs can couple with deep convection, leading to a substantial modulation of clouds and rainfall. EWs are amongst the dynamic features of the troposphere with the longest intrinsic predictability, and models are beginning to forecast them with an exploitable level of skill. Most of the methods developed to identify and objectively isolate EWs in observations and model fields rely on (or at least refer to) the adiabatic, frictionless linearized primitive equations on the sphere or the shallow-water system on the equatorial β$$\beta$$-plane. Common ingredients to these methods are zonal wave-number–frequency filtering (Fourier or wavelet) and/or projections onto predefined empirical or theoretical dynamical patterns. This paper gives an overview of six different methods to isolate EWs and their structures, discusses the underlying assumptions, evaluates the applicability to different problems, and provides a systematic comparison based on a case study (February 20–May 20, 2009) and a climatological analysis (2001–2018). In addition, the influence of different input fields (e.g., winds, geopotential, outgoing long-wave radiation, rainfall) is investigated. Based on the results, we generally recommend employing a combination of wave-number–frequency filtering and spatial-projection methods (and of different input fields) to check for robustness of the identified signal. In cases of disagreement, one needs to carefully investigate which assumptions made for the individual methods are most probably not fulfilled. This will help in choosing an approach optimally suited to a given problem at hand and avoid misinterpretation of the results. convection; equatorial Rossby waves; Kelvin waves; mixed Rossby–gravity waves; spatial projection; time–space filtering; tropical rainfall
Kooperman, G. J.; Akinsanola, A. A.; Hannah, W. M.; Pendergrass, A. G.; Reed, K. A.Kooperman, G. J., A. A. Akinsanola, W. M. Hannah, A. G. Pendergrass, K. A. Reed, 2022: Assessing Two Approaches for Enhancing the Range of Simulated Scales in the E3SMv1 and the Impact on the Character of Hourly US Precipitation. Geophysical Research Letters, 49(4), e2021GL096717. doi: 10.1029/2021GL096717. Improving the representation of precipitation in Earth system models is essential for understanding and projecting water cycle changes across scales. Progress has been hampered by persistent deficiencies in representing precipitation frequency, intensity, and timing in current models. Here, we analyze simulated US precipitation in the low-resolution (LR) configuration of the Energy Exascale Earth System Model (E3SMv1) and assess the effect of two approaches to enhance the range of explicitly resolved scales: high-resolution (HR) and multiscale modeling framework (MMF), which incur similar computational expense. Both E3SMv1-MMF and E3SMv1-HR capture more intense and less frequent precipitation on hourly and daily timescales relative to E3SMv1-LR. E3SMv1-HR improves the intensity over the Eastern and Northwestern US during winter, while E3SMv1-MMF improves the intensity over the Eastern US and summer diurnal timing over the Central US. These results indicate that both methods may be needed to improve simulations of different storm types, seasons, and regions. United States; precipitation; earth system model; energy exascale earth system model; high resolution; multiscale modelling framework
Koppa, Akash; Rains, Dominik; Hulsman, Petra; Poyatos, Rafael; Miralles, Diego G.Koppa, A., D. Rains, P. Hulsman, R. Poyatos, D. G. Miralles, 2022: A deep learning-based hybrid model of global terrestrial evaporation. Nature Communications, 13(1), 1912. doi: 10.1038/s41467-022-29543-7. Terrestrial evaporation (E) is a key climatic variable that is controlled by a plethora of environmental factors. The constraints that modulate the evaporation from plant leaves (or transpiration, Et) are particularly complex, yet are often assumed to interact linearly in global models due to our limited knowledge based on local studies. Here, we train deep learning algorithms using eddy covariance and sap flow data together with satellite observations, aiming to model transpiration stress (St), i.e., the reduction of Et from its theoretical maximum. Then, we embed the new St formulation within a process-based model of E to yield a global hybrid E model. In this hybrid model, the St formulation is bidirectionally coupled to the host model at daily timescales. Comparisons against in situ data and satellite-based proxies demonstrate an enhanced ability to estimate St and E globally. The proposed framework may be extended to improve the estimation of E in Earth System Models and enhance our understanding of this crucial climatic variable. Hydrology; Ecological modelling
Kuma, Peter; Bender, Frida A.-M.; Schuddeboom, Alex; McDonald, Adrian J.; Seland, ØyvindKuma, P., F. A. Bender, A. Schuddeboom, A. J. McDonald, Ø. Seland, 2022: Machine learning of cloud types shows higher climate sensitivity is associated with lower cloud biases. Atmospheric Chemistry and Physics Discussions, 1-32. doi: 10.5194/acp-2022-184. Abstract. Uncertainty in cloud feedback in climate models is a major limitation in projections of future climate. Therefore, to ensure the accuracy of climate models, evaluation and improvement of cloud simulation is essential. We analyse cloud biases and cloud change with respect to global mean near-surface temperature (GMST) in climate models relative to satellite observations, and relate them to equilibrium climate sensitivity, transient climate response and cloud feedback. For this purpose, we develop a supervised deep convolutional artificial neural network for determination of cloud types from low-resolution (approx. 1°×1°) daily mean top of atmosphere shortwave and longwave radiation fields, corresponding to the World Meteorological Organization (WMO) cloud genera recorded by human observers in the Global Telecommunication System. We train this network on a satellite top of atmosphere radiation observed by the Clouds and the Earth’s Radiant Energy System (CERES), and apply it on the Climate Model Intercomparison Project phase 5 and 6 (CMIP5 and CMIP6) historical and abrupt-4xCO2 experiment model output and the ECMWF Reanalysis version 5 (ERA5) and the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) reanalyses. We compare these with satellite observations, link biases in cloud type occurrence derived from the neural network to change with respect to GMST to climate sensitivity, and compare our cloud types with an existing cloud regime classification based on the Moderate Resolution Imaging Spectroradiometer (MODIS) and International Satellite Cloud Climatology Project (ISCCP) satellite data. We show that there is a significant negative linear relationship between the root mean square error of cloud type occurrence derived from the neural network and model equilibrium climate sensitivity and transient climate response (Bayes factor 22 and 17, respectively). This indicates that models with a better representation of the cloud types globally have higher climate sensitivity. Factoring in results from other studies, there are two possible explanations: either high climate sensitivity models are plausible, contrary to combined assessments of climate sensitivity by previous review studies, or the accuracy of representation of present-day clouds in models is negatively correlated with the accuracy of representation of future projected clouds.
Kuwano, A.; Evan, A.Kuwano, A., A. Evan, 2022: A Method to Account for the Impact of Water Vapor on Observation-Based Estimates of the Clear-Sky Shortwave Direct Radiative Effect of Mineral Dust. Journal of Geophysical Research: Atmospheres, 127(17), e2022JD036620. doi: 10.1029/2022JD036620. The shortwave direct radiative effect of dust, the difference between net shortwave radiative flux in a cloud free and cloud and aerosol free atmosphere, is typically estimated using forward calculations made with a radiative transfer model. However, estimates of the direct radiative effect made via this initial method can be highly uncertain due to difficultly in accurately describing the relevant optical and physical properties of dust used in these calculations. An alternative approach to estimate this effect is to determine the forcing efficiency, or the direct radiative effect normalized by aerosol optical depth. While this approach avoids the uncertainties associated with the initial method for calculating the direct effect, random errors and biases associated with this approach have not been thoroughly examined in literature. Here we explore biases in this observation-based approach that are related to atmospheric water vapor. We use observations to show that over the Sahara Desert dust optical depth and column-integrated atmospheric water vapor are positively correlated. We use three idealized radiative models of varying complexity to demonstrate that a positive correlation between dust and water vapor produces a positive bias in the dust forcing efficiency estimated via the observation-based method. We describe a simple modification to the observation-based method that correctly accounts for the correlation between dust and water vapor when estimating the forcing efficiency and use this method to estimate the instantaneous forcing efficiency of dust over the Sahara Desert using satellite data, obtaining −12.3 ± 6.68 to 20.9 ± 11.9 W m−2 per unit optical depth. shortwave; radiative transfer; satellite data; observations; dust; forcing efficiency
Lee, Jae N.; Wu, Dong L.Lee, J. N., D. L. Wu, 2022: Non-Gaussian Distributions of TOA SW Flux as Observed by MISR and CERES. Journal of Geophysical Research: Atmospheres, 127(14), e2022JD036636. doi: 10.1029/2022JD036636. The Top of Atmosphere (TOA) shortwave (SW) flux, converted from Terra Multi-angle Imaging SpectroRadiometer (MISR) narrow band albedos, is compared with that measured from Clouds and the Earth's Radiant Energy System (CERES). We describe the probability density function (PDF) of the monthly TOA SW flux and how the statistical third moment, skewness, can impact the quantification of the flux. The PDF of the SW flux is not normally distributed but positively skewed. In both sets of observations, the near-global (80 S–80 N) median value of the SW flux is ∼3 W/m2 less than the mean value, due to the positive skewness of the distribution. The near-global mean TOA SW flux converted from MISR is about 7 W/m2 (∼7%) less than CERES measured flux during the last two decades. Surprisingly, a hemispheric asymmetry exists with TOA SW observations from the Terra platform. SH reflects 3.92 and 1.15 W/m2 more mean SW flux than NH, from MISR and CERES Single Scanner Footprint products, respectively. We can infer that the offsetting by morning clouds in the SH is greater than the effect of hemispheric imbalance of SW flux caused by different land masses in two hemispheres. While the characteristics of the two SW fluxes broadly agree with each other, differences in the regional PDF from two different SW fluxes are substantial over high cloud regions and high altitude regions. Our analysis shows that some parts of the different skewness from the two measurements may be attributed to the different calibration of the radiance anisotropy over high cloud scenes. CERES; MISR; hemispheric asymmetry; non-Gaussian; TOA SW flux
Lee, Jiheun; Kang, Sarah M.; Kim, Hanjun; Xiang, BaoqiangLee, J., S. M. Kang, H. Kim, B. Xiang, 2022: Disentangling the effect of regional SST bias on the double-ITCZ problem. Climate Dynamics. doi: 10.1007/s00382-021-06107-x. This study investigates the causes of the double intertropical convergence zone (ITCZ) bias, characterized by too northward northern Pacific ITCZ, too dry equatorial Pacific, and too zonally elongated southern Pacific rainband. While the biases within one fully coupled model GFDL CM2.1 are examined, the large-scale bias patterns are broadly common to CMIP5/6 models. We disentangle the individual contribution of regional sea surface temperature (SST) biases to the double-ITCZ bias pattern using a series of slab ocean model experiments. A previously suggested Southern Ocean warm bias effect in displacing the zonal-mean ITCZ southward is manifested in the northern Pacific ITCZ while having little contribution to the zonally elongated wet bias south of the equatorial Pacific. The excessive southern Pacific precipitation is instead induced by the warm bias along the west coast of South America. The Southern Ocean bias effect on the zonal-mean ITCZ position is diminished by the neighboring midlatitude bias of opposite sign in GFDL CM2.1. As a result, the northern extratropical cold bias turns out to be most responsible for a southward-displaced zonal-mean ITCZ. However, this southward ITCZ displacement results from the northern Pacific branch, so ironically fixing the extratropical biases only deteriorates the northern Pacific precipitation bias. Thus, we emphasize that the zonal-mean diagnostics poorly represent the spatial pattern of the tropical Pacific response. Examination of longitude-latitude structure indicates that the overall tropical precipitation bias is mostly locally driven from the tropical SST bias. While our model experiments are idealized with no ocean dynamics, the results shed light on where preferential foci should be applied in model development to improve particular features of tropical precipitation bias.
Leng, Song; Huete, Alfredo; Cleverly, Jamie; Gao, Sicong; Yu, Qiang; Meng, Xianyong; Qi, Junyu; Zhang, Rongrong; Wang, QianfengLeng, S., A. Huete, J. Cleverly, S. Gao, Q. Yu, X. Meng, J. Qi, R. Zhang, Q. Wang, 2022: Assessing the Impact of Extreme Droughts on Dryland Vegetation by Multi-Satellite Solar-Induced Chlorophyll Fluorescence. Remote Sensing, 14(7), 1581. doi: 10.3390/rs14071581. Satellite-estimated solar-induced chlorophyll fluorescence (SIF) is proven to be an effective indicator for dynamic drought monitoring, while the capability of SIF to assess the variability of dryland vegetation under water and heat stress remains challenging. This study presents an analysis of the responses of dryland vegetation to the worst extreme drought over the past two decades in Australia, using multi-source spaceborne SIF derived from the Global Ozone Monitoring Experiment-2 (GOME-2) and TROPOspheric Monitoring Instrument (TROPOMI). Vegetation functioning was substantially constrained by this extreme event, especially in the interior of Australia, in which there was hardly seasonal growth detected by neither satellite-based observations nor tower-based flux measurements. At a 16-day interval, both SIF and enhanced vegetation index (EVI) can timely capture the reduction at the onset of drought over dryland ecosystems. The results demonstrate that satellite-observed SIF has the potential for characterizing and monitoring the spatiotemporal dynamics of drought over water-limited ecosystems, despite coarse spatial resolution coupled with high-retrieval noise as compared with EVI. Furthermore, our study highlights that SIF retrieved from TROPOMI featuring substantially enhanced spatiotemporal resolution has the promising capability for accurately tracking the drought-induced variation of heterogeneous dryland vegetation. SIF; dryland; EVI; extreme drought; TROPOMI
Leng, Song; Huete, Alfredo; Cleverly, Jamie; Yu, Qiang; Zhang, Rongrong; Wang, QianfengLeng, S., A. Huete, J. Cleverly, Q. Yu, R. Zhang, Q. Wang, 2022: Spatiotemporal Variations of Dryland Vegetation Phenology Revealed by Satellite-Observed Fluorescence and Greenness across the North Australian Tropical Transect. Remote Sensing, 14(13), 2985. doi: 10.3390/rs14132985. Accurate characterization of spatial patterns and temporal variations in dryland vegetation is of great importance for improving our understanding of terrestrial ecosystem functioning under changing climates. Here, we explored the spatiotemporal variability of dryland vegetation phenology using satellite-observed Solar-Induced chlorophyll Fluorescence (SIF) and the Enhanced Vegetation Index (EVI) along the North Australian Tropical Transect (NATT). Substantial impacts of extreme drought and intense wetness on the phenology and productivity of dryland vegetation are observed by both SIF and EVI, especially in the arid/semiarid interior of Australia without detectable seasonality in the dry year of 2018–2019. The greenness-based vegetation index (EVI) can more accurately capture the seasonal and interannual variation in vegetation production than SIF (EVI r2: 0.47~0.86, SIF r2: 0.47~0.78). However, during the brown-down periods, the rate of decline in EVI is evidently slower than that in SIF and in situ measurement of gross primary productivity (GPP), due partially to the advanced seasonality of absorbed photosynthetically active radiation. Over 70% of the variability of EVI (except for Hummock grasslands) and 40% of the variability of SIF (except for shrublands) can be explained by the water-related drivers (rainfall and soil moisture). By contrast, air temperature contributed to 25~40% of the variability of the effective fluorescence yield (SIFyield) across all biomes. In spite of high retrieval noises and variable accuracy in phenological metrics (MAE: 8~60 days), spaceborne SIF observations, offsetting the drawbacks of greenness-based phenology products with a potentially lagged end of the season, have the promising capability of mapping and characterizing the spatiotemporal dynamics of dryland vegetation phenology. SIF; EVI; NATT; phenology
Li, Lingfeng; Qiu, Bo; Guo, Weidong; Zhang, Yiping; Song, Qinghai; Chen, JiuyiLi, L., B. Qiu, W. Guo, Y. Zhang, Q. Song, J. Chen, 2022: Phenological and physiological responses of the terrestrial ecosystem to the 2019 drought event in Southwest China: Insights from satellite measurements and the SSiB2 model. International Journal of Applied Earth Observation and Geoinformation, 111, 102832. doi: 10.1016/j.jag.2022.102832. Understanding plant phenological and physiological changes in response to drought will provide key insight into the response of terrestrial ecosystems to climate change, but is still limited due to the increased drought severity and frequency in recent decades. Here, we combine solar-induced chlorophyll fluorescence (SIF) along with SSiB2 (Simplified Simple Biosphere Model) simulations to investigate the plant phenological and physiological responses to the 2019 drought in southwestern China. Our results show that this 2019 drought had substantial impacts on vegetation phenology and photosynthesis due to the soil moisture deficit in spring, while the rewatering process in July alleviated the water deficit and reduced drought damage to plants. Moreover, SIF observations provide a physiology-related vegetation response, as the recovery of plant photosynthesis indicated by fluorescence yield (SIFyield) is much stronger than the recovery of greenness described by vegetation indices during the rewatering in July. The SSiB2 simulations captured the physiological response of plants to moisture deficit during drought period, while the lack of realistic energy dissipation mechanisms under stressed conditions may lead to discrepancies in the timing of peak response to drought. Our findings highlight the prospective application of remote sensing SIF measurements in monitoring the timely response of plant physiology to changes in water conditions and to provide important information for model evaluation and improvement. Solar-induced chlorophyll fluorescence; Drought; Plant physiological response; Water stress
Li, Meng; Chu, Ronghao; Sha, Xiuzhu; Xie, Pengfei; Ni, Feng; Wang, Chao; Jiang, Yuelin; Shen, Shuanghe; Islam, Abu Reza Md TowfiqulLi, M., R. Chu, X. Sha, P. Xie, F. Ni, C. Wang, Y. Jiang, S. Shen, A. R. M. T. Islam, 2022: Monitoring 2019 Drought and Assessing Its Effects on Vegetation Using Solar-Induced Chlorophyll Fluorescence and Vegetation Indexes in the Middle and Lower Reaches of Yangtze River, China. Remote Sensing, 14(11), 2569. doi: 10.3390/rs14112569. Monitoring drought precisely and evaluating drought effects quantitatively can establish a scientific foundation for understanding drought. Although solar-induced chlorophyll fluorescence (SIF) can detect the drought stress in advance, the performance of SIF in monitoring drought and assessing drought-induced gross primary productivity (GPP) losses from lush to senescence remains to be further studied. Taking the 2019 drought in the middle and lower reaches of the Yangtze River (MLRYR) as an example, this study aims to monitor and assess this drought by employing a new global, OCO-2-based SIF (GOSIF) and vegetation indexes (VIs). Results showed that the GPP, GOSIF, and VIs all exhibited significant increasing trends during 2000–2020. GOSIF was most consistent with GPP in spatial distribution and was most correlated with GPP in both annual (linear correlation, R2 = 0.87) and monthly (polynomial correlation, R2 = 0.976) time scales by comparing with VIs. During July–December 2019, the precipitation (PPT), soil moisture, and standardized precipitation evapotranspiration index (SPEI) were generally below the averages during 2011–2020 and reached their lowest point in November, while those of air temperature (Tem), land surface temperature (LST), and photosynthetically active radiation (PAR) were the contrary. For drought monitoring, the spatial distributions of standardized anomalies of GOSIF and VIs were consistent during August–October 2019. In November and December, however, considering vegetation has entered the senescence stage, SIF had an obvious early response in vegetation physiological state monitoring compared with VIs, while VIs can better indicate meteorological drought conditions than SIF. For drought assessment, the spatial distribution characteristics of GOSIF and its standardized anomaly were both most consistent with that of GPP, especially the standardized anomaly in November and December. All the above phenomena verified the good spatial consistency between SIF and GPP and the superior ability of SIF in capturing and quantifying drought-induced GPP losses. Results of this study will improve the understanding of the prevention and reduction in agrometeorological disasters and can provide an accurate and timely method for drought monitoring. drought; solar-induced chlorophyll fluorescence; gross primary productivity; the middle and lower reaches of Yangtze River; vegetation indexes
Li, Ming; Letu, Husi; Peng, Yiran; Ishimoto, Hiroshi; Lin, Yanluan; Nakajima, Takashi Y.; Baran, Anthony J.; Guo, Zengyuan; Lei, Yonghui; Shi, JianchengLi, M., H. Letu, Y. Peng, H. Ishimoto, Y. Lin, T. Y. Nakajima, A. J. Baran, Z. Guo, Y. Lei, J. Shi, 2022: Investigation of ice cloud modeling capabilities for the irregularly shaped Voronoi ice scattering models in climate simulations. Atmospheric Chemistry and Physics, 22(7), 4809-4825. doi: 10.5194/acp-22-4809-2022. Abstract. Both weather–climate models and ice cloud remote sensing applications need to obtain effective ice crystal scattering (ICS) properties and the parameterization scheme. An irregularly shaped Voronoi ICS model has been suggested to be effective in remote sensing applications for several satellite programs, e.g., Himawari-8, GCOM-C (Global Change Observation Mission–Climate) and EarthCARE (Earth Cloud Aerosol and Radiation Explorer). As continuation work of Letu et al. (2016), an ice cloud optical property parameterization scheme (Voronoi scheme) of the Voronoi ICS model is employed in the Community Integrated Earth System Model (CIESM) to simulate the optical and radiative properties of ice clouds. We utilized the single-scattering properties (extinction efficiency, single-scattering albedo and asymmetry factor) of the Voronoi model from the ultraviolet to the infrared, combined with 14 408 particle size distributions obtained from aircraft measurements to complete the Voronoi scheme. The Voronoi scheme and existing schemes (Fu, Mitchell, Yi and Baum-yang05) are applied to the CIESM to simulate 10-year global cloud radiative effects during 2001–2010. Simulated globally averaged cloud radiative forcings at the top of the atmosphere (TOA) for Voronoi and the other four existing schemes are compared to the Clouds and the Earth's Radiant Energy System Energy Balanced and Filled (EBAF) product. The results show that the differences in shortwave and longwave globally averaged cloud radiative forcing at the TOA between the Voronoi scheme simulations and EBAF products are 1.1 % and 1.4 %, which are lower than those of the other four schemes. Particularly for regions (from 30∘ S to 30∘ N) where ice clouds occur frequently, the Voronoi scheme provides the closest match with EBAF products compared with the other four existing schemes. The results in this study fully demonstrated the effectiveness of the Voronoi ICS model in the simulation of the radiative properties of ice clouds in the climate model.
Li, Shaopeng; Jiang, Bo; Peng, Jianghai; Liang, Hui; Han, Jiakun; Yao, Yunjun; Zhang, Xiaotong; Cheng, Jie; Zhao, Xiang; Liu, Qiang; Jia, KunLi, S., B. Jiang, J. Peng, H. Liang, J. Han, Y. Yao, X. Zhang, J. Cheng, X. Zhao, Q. Liu, K. Jia, 2022: Estimation of the All-Wave All-Sky Land Surface Daily Net Radiation at Mid-Low Latitudes from MODIS Data Based on ERA5 Constraints. Remote Sensing, 14(1), 33. doi: 10.3390/rs14010033. The surface all-wave net radiation (Rn) plays an important role in the energy and water cycles, and most studies of Rn estimations have been conducted using satellite data. As one of the most commonly used satellite data sets, Moderate Resolution Imaging Spectroradiometer (MODIS) data have not been widely used for radiation calculations at mid-low latitudes because of its very low revisit frequency. To improve the daily Rn estimation at mid-low latitudes with MODIS data, four models, including three models built with random forest (RF) and different temporal expansion models and one model built with the look-up-table (LUT) method, are used based on comprehensive in situ radiation measurements collected from 340 globally distributed sites, MODIS top-of-atmosphere (TOA) data, and the fifth generation of European Centre for Medium-Range Weather Forecasts Reanalysis 5 (ERA5) data from 2000 to 2017. After validation against the in situ measurements, it was found that the RF model based on the constraint of the daily Rn from ERA5 (an RF-based model with ERA5) performed the best among the four proposed models, with an overall validated root-mean-square error (RMSE) of 21.83 Wm−2, R2 of 0.89, and a bias of 0.2 Wm−2. It also had the best accuracy compared to four existing products (Global LAnd Surface Satellite Data (GLASS), Clouds and the Earth’s Radiant Energy System Edition 4A (CERES4A), ERA5, and FLUXCOM_RS) across various land cover types and different elevation zones. Further analyses illustrated the effectiveness of the model by introducing the daily Rn from ERA5 into a “black box” RF-based model for Rn estimation at the daily scale, which is used as a physical constraint when the available satellite observations are too limited to provide sufficient information (i.e., when the overpass time is less than twice per day) or the sky is overcast. Overall, the newly-proposed RF-based model with ERA5 in this study shows satisfactory performance and has strong potential to be used for long-term accurate daily Rn global mapping at finer spatial resolutions (e.g., 1 km) at mid-low latitudes. modeling; MODIS; net radiation; energy balance; ERA5; constraint; mid-low latitude; random forest; temporal expansion
Li, Xiaohan; Zhang, Yi; Peng, Xindong; Chu, Wenchao; Lin, Yanluan; Li, JianLi, X., Y. Zhang, X. Peng, W. Chu, Y. Lin, J. Li, 2022: Improved Climate Simulation by Using a Double-Plume Convection Scheme in a Global Model. Journal of Geophysical Research: Atmospheres, 127(11), e2021JD036069. doi: 10.1029/2021JD036069. Convective parameterization can drastically regulate the mean climate and tropical transient activity of a General circulation model (GCM). In this study, the physics suite of the NCAR Community Atmosphere Model, version 5 (CAM5) was first ported to the Global-to-Regional Integrated Forecast System model. Then, the original convective parameterization of CAM5—with a separate representation of deep convection Zhang–Mcfarlane (ZM) and shallow convection University of Washington (UW)—was replaced by a double-plume (DP) scheme. This DP scheme adopts a quasi-unified representation of shallow and deep convection within a single framework. Results demonstrate that the new scheme brings about several improvements in the modeled climate. The differences in the trigger and closure assumptions, lateral mixing rate, and cloud model for the deep convection result in systematic regional differences in the simulated precipitation pattern, cloud vertical structure, and the associated radiative forcing. Compared with ZM-UW, DP reduces the biases in precipitation over the Indian Ocean, ameliorates the “high-frequency and low-intensity” problem of tropical precipitation, and leads to an improved representation of tropical variability, including the Madden–Julian Oscillation. Double-plume reduces low clouds and increases high clouds in the tropics, due to its internal parallel-split convective processes and smaller cumulus cloud fraction. Discussions related to parametric tuning of convective parameterization are also presented.
Liang, Hui; Jiang, Bo; Liang, Shunlin; Peng, Jianghai; Li, Shaopeng; Han, Jiakun; Yin, Xiuwan; Cheng, Jie; Jia, Kun; Liu, Qiang; Yao, Yunjun; Zhao, Xiang; Zhang, XiaotongLiang, H., B. Jiang, S. Liang, J. Peng, S. Li, J. Han, X. Yin, J. Cheng, K. Jia, Q. Liu, Y. Yao, X. Zhao, X. Zhang, 2022: A global long-term ocean surface daily/0.05° net radiation product from 1983–2020. Scientific Data, 9(1), 337. doi: 10.1038/s41597-022-01419-x. The all-wave net radiation (Rn) on the ocean surface characterizes the available radiative energy balance and is important to understand the Earth’s climate system. Considering the shortcomings of available ocean surface Rn datasets (e.g., coarse spatial resolutions, discrepancy in accuracy, inconsistency, and short duration), a new long-term global daily Rn product at a spatial resolution of 0.05° from 1983 to 2020, as part of the Global High Resolution Ocean Surface Energy (GHOSE) products suite, was generated in this study by fusing several existing datasets including satellite and reanalysis products based on the comprehensive in situ measurements from 68 globally distributed moored buoy sites. Evaluation against in-situ measurements shows the root mean square difference, mean bias error and correlation coefficient squared of 23.56 Wm−2, 0.88 Wm−2 and 0.878. The global average ocean surface Rn over 1983–2020 is estimated to be 119.71 ± 2.78 Wm−2 with a significant increasing rate of 0.16 Wm−2 per year. GHOSE Rn product can be valuable for oceanic and climatic studies. Physical oceanography
Lin, Qiao-Jun; Yu, Jia-YuhLin, Q., J. Yu, 2022: The potential impact of model horizontal resolution on the simulation of atmospheric cloud radiative effect in CMIP6 models. Terrestrial, Atmospheric and Oceanic Sciences, 33(1), 21. doi: 10.1007/s44195-022-00021-3. The simulations of atmospheric cloud-radiative effect (ACRE) from 54 Coupled Model Intercomparison Project phase 6 (CMIP6) models during the historical period of 2000/03–2014/12 are compared and evaluated against the satellite-based Clouds and the Earth’s Radiant Energy System (CERES) products. For ease of comparison, all CMIP6 models are divided into high-, medium-, and low-resolution groups to examine the potential impact of model horizontal resolution change on the simulations of ACRE distribution over the tropical oceans. The results show that ACRE is positive inside the ITCZs but negative in the subtropics and cold tongue areas, owing to the very different radiative forcing between deep and shallow clouds. Simulations of ACRE are sensitive to the model horizontal resolution used and the finer resolution models generally produce a better performance of ACRE simulations against the CERES observations. The reduced ACRE biases in finer resolution models are mainly contributed by the improved longwave ACRE (i.e., LWACRE) simulations, especially over the Pacific and Atlantic cold tongue areas where shallow stratocumulus clouds prevail. CMIP6; Atmospheric cloud-radiative effect; Model horizontal resolution
Lindzen, Richard S.; Choi, Yong-SangLindzen, R. S., Y. Choi, 2022: The Iris Effect: A Review. Asia-Pacific Journal of Atmospheric Sciences, 58(1), 159-168. doi: 10.1007/s13143-021-00238-1. This study reviews the research of the past 20-years on the role of anvil cirrus in the Earth’s climate – research initiated by Lindzen et al. (Bull. Am. Meteor. Soc. 82:417-432, 2001). The original study suggested that the anvil cirrus would shrink with warming, which was estimated to induce longwave cooling for the Earth. This is referred to as the iris effect since the areal change hypothetically resembles the light control by the human eye’s iris. If the effect is strong enough, it exerts a significant negative climate feedback which stabilizes tropical temperatures and limits climate sensitivity. Initial responses to Lindzen et al. (Bull. Am. Meteor. Soc. 82:417-432, 2001) denied the existence and effectiveness of the iris effect. Assessment of the debatable issues in these responses will be presented later in this review paper. At this point, the strong areal reduction of cirrus with warming appears very clearly in both climate models and satellite observations. Current studies found that the iris effect may not only come from the decreased cirrus outflow due to increased precipitation efficiency, but also from concentration of cumulus cores over warmer areas (the so-called aggregation effect). Yet, different opinions remain as to the radiative effect of cirrus clouds participating in the iris effect. For the iris effect to be most important, it must involve cirrus clouds that are not as opaque for visible radiation as they are for infrared radiation. However, current climate models often simulate cirrus clouds that are opaque in both visible and infrared radiation. This issue requires thorough examination as it seems to be opposed to conventional wisdom based on explicit observations. This paper was written in the hope of stimulating more effort to carefully evaluate these important issues.
Liu, Chunlei; Yang, Yazhu; Liao, Xiaoqing; Cao, Ning; Liu, Jimmy; Ou, Niansen; Allan, Richard P.; Jin, Liang; Chen, Ni; Zheng, RongLiu, C., Y. Yang, X. Liao, N. Cao, J. Liu, N. Ou, R. P. Allan, L. Jin, N. Chen, R. Zheng, 2022: Discrepancies in Simulated Ocean Net Surface Heat Fluxes over the North Atlantic. Advances in Atmospheric Sciences. doi: 10.1007/s00376-022-1360-7. The change in ocean net surface heat flux plays an important role in the climate system. It is closely related to the ocean heat content change and ocean heat transport, particularly over the North Atlantic, where the ocean loses heat to the atmosphere, affecting the AMOC (Atlantic Meridional Overturning Circulation) variability and hence the global climate. However, the difference between simulated surface heat fluxes is still large due to poorly represented dynamical processes involving multiscale interactions in model simulations. In order to explain the discrepancy of the surface heat flux over the North Atlantic, datasets from nineteen AMIP6 and eight highresSST-present climate model simulations are analyzed and compared with the DEEPC (Diagnosing Earth’s Energy Pathways in the Climate system) product. As an indirect check of the ocean surface heat flux, the oceanic heat transport inferred from the combination of the ocean surface heat flux, sea ice, and ocean heat content tendency is compared with the RAPID (Rapid Climate Change-Meridional Overturning Circulation and Heat flux array) observations at 26°N in the Atlantic. The AMIP6 simulations show lower inferred heat transport due to less heat loss to the atmosphere. The heat loss from the AMIP6 ensemble mean north of 26°N in the Atlantic is about 10 W m−2 less than DEEPC, and the heat transport is about 0.30 PW (1 PW = 1015 W) lower than RAPID and DEEPC. The model horizontal resolution effect on the discrepancy is also investigated. Results show that by increasing the resolution, both surface heat flux north of 26°N and heat transport at 26°N in the Atlantic can be improved. observations; ocean heat transport; discrepancy; ocean net surface heat flux; simulations
Liu, Le; Wu, Bingyi; Ding, ShuoyiLiu, L., B. Wu, S. Ding, 2022: On the Association of the Summertime Shortwave Cloud Radiative Effect in Northern Russia With Atmospheric Circulation and Climate Over East Asia. Geophysical Research Letters, 49(2), e2021GL096606. doi: 10.1029/2021GL096606. This study employs ERA5 reanalysis and CERES/EBAF Ed4.1 data to evaluate the dominant features of summer shortwave cloud radiative effect (SWCRE) variability and associated atmospheric circulation anomalies. Our findings suggest that the greatest variability in summer SWCRE occurs over the Barents, Kara, and Laptev seas and northern Eurasia. We also observe a close relationship between summertime SWCRE, particularly in northern Russia, and atmospheric circulation variability over East Asia. Significant positive SWCRE anomalies over northern Russia favor the generation of the Ural blocking, and dynamically trigger the emergence of positive Eurasian (EU) pattern, resulting in positive (negative) precipitation anomalies in northern (southeastern) China and persistent East Asian heatwaves between 20°N and 40°N. In contrast to previous work, which has focused mainly on local atmospheric responses to SWCRE, this study provides a broader perspective, thereby helping bridge summertime circulation between high latitudes and East Asia. shortwave cloud radiative effect; East Asian atmospheric circulation variability; Eurasian teleconnection; Ural blocking
Liu, Yawen; Wang, Minghuai; Qian, Yun; Ding, AijunLiu, Y., M. Wang, Y. Qian, A. Ding, 2022: A Strong Anthropogenic Black Carbon Forcing Constrained by Pollution Trends Over China. Geophysical Research Letters, 49(10), e2022GL098965. doi: 10.1029/2022GL098965. Estimates of the effective radiative forcing from aerosol-radiation interaction (ERFari) of anthropogenic Black Carbon (BC) have been disputable and require better constraints. Here we find a substantial decline in atmospheric absorption of −5.79Wm−2decade−1 over eastern central China (ECC) responding to recent anthropogenic BC emission reductions. By combining the observational finding with advances from Coupled Model Intercomparison Project phase6 (CMIP6), we identify an emergent constraint on the ERFari of anthropogenic BC. We show that across CMIP6 models the simulated trends correlate well with simulated annual mean shortwave atmospheric absorption by anthropogenic BC over China. Making use of this emergent relationship allows us to constrain the aerosol absorption optical depth of anthropogenic BC and further provide a constrained range of 2.4–3.0 Wm−2 for its top-of-atmosphere ERFari over China, higher than existing estimates. Our work supports a strong warming effect of BC over China, and highlights the need to improve BC simulations over source regions. CMIP6 models; anthropogenic black carbon; effective radiative forcing from aerosol-radiation interaction; long-term trend; observational constraint
Loeb, Norman G.; Mayer, Michael; Kato, Seiji; Fasullo, John T.; Zuo, Hao; Senan, Retish; Lyman, John M.; Johnson, Gregory C.; Balmaseda, MagdalenaLoeb, N. G., M. Mayer, S. Kato, J. T. Fasullo, H. Zuo, R. Senan, J. M. Lyman, G. C. Johnson, M. Balmaseda, 2022: Evaluating Twenty-Year Trends in Earth's Energy Flows From Observations and Reanalyses. Journal of Geophysical Research: Atmospheres, 127(12), e2022JD036686. doi: 10.1029/2022JD036686. Satellite, reanalysis, and ocean in situ data are analyzed to evaluate regional, hemispheric and global mean trends in Earth's energy fluxes during the first 20 years of the twenty-first century. Regional trends in net top-of-atmosphere (TOA) radiation from the Clouds and the Earth's Radiant Energy System (CERES), ECMWF Reanalysis 5 (ERA5), and a model similar to ERA5 with prescribed sea surface temperature (SST) and sea ice differ markedly, particularly over the Eastern Pacific Ocean, where CERES observes large positive trends. Hemispheric and global mean net TOA flux trends for the two reanalyses are smaller than CERES, and their climatological means are half those of CERES in the southern hemisphere (SH) and more than nine times larger in the northern hemisphere (NH). The regional trend pattern of the divergence of total atmospheric energy transport (TEDIV) over ocean determined using ERA5 analyzed fields is similar to that inferred from the difference between TOA and surface fluxes from ERA5 short-term forecasts. There is also agreement in the trend pattern over ocean for surface fluxes inferred as a residual between CERES net TOA flux and ERA5 analysis TEDIV and surface fluxes obtained directly from ERA5 forecasts. Robust trends are observed over the Gulf Stream associated with enhanced surface-to-atmosphere transfer of heat. Within the ocean, larger trends in ocean heating rate are found in the NH than the SH after 2005, but the magnitude of the trend varies greatly among datasets.
Lv, Mingzhu; Song, Yan; Li, Xijia; Wang, Mengsi; Qu, YingLv, M., Y. Song, X. Li, M. Wang, Y. Qu, 2022: Spatiotemporal characteristics and driving factors of global planetary albedo: an analysis using the Geodetector method. Theoretical and Applied Climatology, 147(1), 737-752. doi: 10.1007/s00704-021-03858-9. As an important parameter of the Earth’s energy budget, the planetary albedo of Earth varies with the dynamics of atmospheric and surface variables. In this study, we investigated the spatiotemporal characteristics and driving factors of the global planetary albedo using the Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) dataset and the Geodetector method. The results revealed that the planetary albedo can be decomposed into atmospheric and surface contributions, and the planetary albedo in the middle and low latitudes was predominantly affected by the atmospheric contribution. The global planetary albedo and the atmospheric and surface contributions exhibited decreasing trends of − 0.0020, − 0.0015, and − 0.0004/decade from 2001 to 2018, respectively, which were closely related to the variations of atmospheric and surface variables. The cloud fraction was the driving factor of the atmospheric contribution in the middle and low latitudes, and its influence was further enhanced by the aerosol optical thickness (AOT), ice water path (IWP), and liquid water path (LWP). The snow/ice coverage and normalized difference vegetation index (NDVI) were the driving factors of the surface contribution in the snow/ice-covered and vegetated areas, respectively. The interaction relationships between the surface variables were mainly bi-enhanced and nonlinearly enhanced. These results provide useful information about the driving factors of the planetary albedo and are benefit for improving the parametrization of the planetary albedo.
Ma, Mengnan; Ou, Tinghai; Liu, Dongqing; Wang, Shuyu; Fang, Juan; Tang, JianpingMa, M., T. Ou, D. Liu, S. Wang, J. Fang, J. Tang, 2022: Summer regional climate simulations over Tibetan Plateau: from gray zone to convection permitting scale. Climate Dynamics. doi: 10.1007/s00382-022-06314-0. The Tibetan Plateau (TP) is often referred to as ‘the Third Pole’ and plays an essential role in the global climate. However, it remains challenging for most global and regional models to realistically simulate the characteristics of climate over the TP. In this study, two Weather Research and Forecasting model (WRF) experiments using spectral nudging with gray-zone (GZ9) and convection-permitting (CP3) resolution are conducted for summers from 2009 to 2018. The surface air temperature (T2m) and precipitation from the two simulations and the global reanalysis ERA5 are evaluated against in-situ observations. The results show that ERA5 has a general cold bias over southern TP, especially in maximum T2m (Tmax), and wet bias over whole TP. Both experiments can successfully capture the spatial pattern and daily variation of T2m and precipitation, though cold bias for temperature and dry bias for precipitation exist especially over the regions south of 35° N. Compared with ERA5, the added value of the two WRF experiments is mainly reflected in the reduced cold bias especially for Tmax with more improvement found in CP3 and the reduced wet bias. However, the ability of the convection-permitting WRF experiment in improving the simulation of precipitation seems limited when compared to the gray-zone WRF experiment, which may be related to the biases in physical parameterization and lack of representativeness of station observation. Further investigation into surface radiation budget reveals that the underestimation of net shortwave radiation contributes a lot to the cold bias of T2m over the southeastern TP in GZ9 which is improved in CP3. Compared with GZ9, CP3 shows that larger specific humidity at low-level (mid-high level) coexists with more precipitation (clouds) over the southern TP. This improvement is achieved by better depiction of topographic details, underlying surface and atmospheric processes, land–atmosphere interactions and so on, leading to stronger northward water vapor transport (WVT) in CP3, providing more water vapor for precipitation at surface and much wetter condition in the mid-high level. Tibetan Plateau; Convection permitting; Gray zone; Spectral nudging; Summer precipitation; Surface air temperature
Ma, Wen; Ding, Jianli; Wang, Jinlong; Zhang, JunyongMa, W., J. Ding, J. Wang, J. Zhang, 2022: Effects of aerosol on terrestrial gross primary productivity in Central Asia. Atmospheric Environment, 288, 119294. doi: 10.1016/j.atmosenv.2022.119294. Aerosols significantly contribute to global and regional climate change by altering the surface solar radiation, thereby affecting plant productivity. Central Asia is a primary source of global dust aerosols. However, the mechanisms of how aerosols affect terrestrial gross primary productivity (GPP), especially in Central Asia, are not clearly understood. In this study, we investigated the spatial variation in aerosol optical depth (AOD) and GPP and the relationship between them during the growing season (April–October) from 2001 to 2018 using remote sensing data from several sources. We created a GWR-SEM model consisting of a geographically weighted model (GWR) coupled with a structural equation model (SEM) to quantify and analyze the effects of AOD on GPP. The results show that AOD decreased slightly at a rate of −0.0002 y−1 during the study period and that there was a tendency towards spatial aggregation. The extent of AOD pollution in the northwest region (around the Aral Sea) was slightly greater than that in the southeast. GPP increased significantly at a rate of 7.2965 g C m−2 y−2, especially in the northern region. There were some differences in the effects of AOD on GPP between different vegetation types; the highest AOD–GPP correlation was found in shrublands and croplands. Analysis of the GWR-SEM model suggested that AOD and two forms of radiation (surface net radiation, SNR, and photosynthetically active radiation, PAR) explained 72.4% (63.4% for 2001, 66.8% for 2018) of the spatial variation in GPP. SNR had the greatest effect on GPP, followed by AOD. Diffuse PAR had the greatest indirect effect on GPP. The findings of this study highlight the importance of aerosol pollution on spatial variation in gross primary productivity, and they provide a methodological framework for investigating the relationship between AOD and GPP in arid areas. GPP; Aerosol optional depth; Central Asia; SEM
Maity, Suman; Nayak, Sridhara; Nayak, Hara Prasad; Bhatla, R.Maity, S., S. Nayak, H. P. Nayak, R. Bhatla, 2022: Comprehensive assessment of RegCM4 towards interannual variability of Indian Summer Monsoon using multi-year simulations. Theoretical and Applied Climatology. doi: 10.1007/s00704-022-03961-5. In this study, the interannual variability (IAV) of Indian Summer Monsoon (ISM) is investigated using multi-year (1982‒2016) seasonal scale simulations (May‒September) of the regional climate model RegCM4. Model-simulated fields such as surface temperature, wind and rainfall are validated initially to testify the climatological behaviour of ISM. Subsequently, different aspects of IAV associated with ISM are discussed primarily focusing on model simulated rainfall and are verified against high-resolution rainfall analysis from India Meteorological Department (IMD). Analysis indicated that RegCM4 shows reasonable accuracy in simulating major large-scale features, however, has cold bias over entire India and wet (dry) bias over northwest and peninsular (central) India. Easterly (westerly) bias is noticed in the model simulated low (upper) level wind that affects regional Hadley circulation. The cold bias is found to be associated with the feedback cycle of land–atmosphere interaction. Surface evaporative cooling likely affects the static instability in the atmospheric column, thereby limiting the convection and thus reducing rainfall. While categorizing, it is noticed that the efficacy of the model is found to be better in simulating normal monsoon as compared to contrasting monsoon (deficit and excess) year, thereby reducing the simulation skill for the entire period. EOF analysis revealed that first two leading modes of IMD rainfall are linked with large-scale variabilities, viz. El-Nino Southern Oscillation and Indian Ocean Dipole, respectively, but RegCM4 could not well reproduce these relationships. The spectral analysis showed 2–7 year periodicity in the model. However, the associated spectral peaks are close to the red noise spectrum due to their weak power suggesting limited model skill to capture large-scale variability. Overall, this study advocates that the RegCM4 could capture the climatological features of ISM fairly well, but needs further improvement in representing the IAV more accurately.
Maloney, Christopher; Toon, Brian; Bardeen, Charles; Yu, Pengfei; Froyd, Karl; Kay, Jennifer; Woods, SarahMaloney, C., B. Toon, C. Bardeen, P. Yu, K. Froyd, J. Kay, S. Woods, 2022: The balance between heterogeneous and homogeneous nucleation of ice clouds using CAM5/CARMA. Journal of Geophysical Research: Atmospheres, e2021JD035540. doi: 10.1029/2021JD035540. We present a modification to the Community Aerosol and Radiation model for Atmospheres (CARMA) sectional ice microphysical model where we have added interactive nucleation of sulfates and heterogeneous nucleation onto dust in order to create a more comprehensive representation of ice nucleation within the CARMA sectional ice model. The convective wet removal fix has also been added in order to correctly transport aerosol within the Community Atmosphere Model version 5 (CAM5) and the 3-mode Modal Aerosols Model (MAM3). In CARMA, the balance of homogeneous and heterogeneous nucleation is controlled by the presence of temperatures below 240 °K, supersaturation, and the availability of heterogeneous nuclei. Due to a paucity of dust at altitudes above about 7 km, where temperatures over most of the Earth fall below 240 °K, cirrus clouds above 7 km nucleate primarily via homogeneous nucleation on aqueous sulfate aerosols in our simulations. Over mid-latitudes of the Northern Hemisphere, dust is more common above 7 km during spring through fall, and both heterogeneous nucleation and homogenous freezing occur in our model. Below 7 km heterogeneous nucleation dominates in situ formation of ice. Furthermore, we find an improvement of the representation of in-cloud ice within mixed phase clouds in CAM5/CARMA when compared to simulations with only homogeneous ice nucleation. Other modes of nucleation such as contact nucleation of liquid cloud droplets or liquid cloud droplet freezing on immersion nuclei, were not directly compared with classical depositional heterogeneous nucleation in this study. Cloud modeling; Dust Aerosol; Heterogeneous nucleation; Homogeneous nucleation; Ice nucleation
Matthews, G.Matthews, G., 2022: Direct Solar Viewing Calibration Concept for Future CERES-, GERB-, or Libera-Type Earth Orbital Climate Missions. J. Atmos. Oceanic Technol., 39(7), 1085-1091. doi: 10.1175/JTECH-D-21-0002.1. Abstract Better predictions of global warming can be enabled by tuning legacy and current computer simulations to Earth radiation budget (ERB) measurements. Since the 1970s, such orbital results exist, and the next-generation instruments such as one called “Libera” are in production. Climate communities have requested that new ERB observing system missions like these have calibration accuracy obtaining significantly improved calibration SI traceability and stability. This is to prevent untracked instrument calibration drifts that could lead to false conclusions on climate change. Based on experience from previous ERB missions, the alternative concept presented here utilizes directly viewing solar calibration, for cloud-size Earth measurement resolution at
Matthews, GrantMatthews, G., 2022: Assessment of Terra/Aqua MODIS and Deep Convective Cloud Albedo Solar Calibration Accuracies and Stabilities Using Lunar Calibrated MERBE Results. Remote Sensing, 14(11), 2517. doi: 10.3390/rs14112517. Moon calibrated radiometrically stable and relatively accurate Earth reflected solar measurements from the Moon and Earth Radiation Budget Experiment (MERBE) are compared here to primary channels of coaligned Terra/Aqua MODIS instruments. A space-based climate observing system immune to untracked drifts due to varying instrument calibration is a key priority for climate science. Measuring these changes in radiometers such as MODIS and compensating for them is critical to such a system. The independent MERBE project using monthly lunar scans has made a proven factor of ten improvement in calibration stability and relative accuracy of measurements by all devices originally built for another project called ‘CERES’, also on the Terra and Aqua satellites. The MERBE comparison shown here uses spectrally invariant Deep Convective Cloud or DCC targets as a transfer, with the objective of detecting possible unknown MODIS calibration trends or errors. Most MODIS channel 1–3 collection 5 calibrations are shown to be correct and stable within stated accuracies of 3% relative to the Moon, much in line with changes made for MODIS collection 6. Stable lunar radiance standards are then separately compared to the sometimes used calibration metric of the coldest DCCs as standalone calibration targets, when also located by MODIS. The analysis overall for the first time finds such clouds can serve as an absolute solar target on the order of 1% accuracy and are stable to ±0.3% decade−1 with two sigma confidences, based on the Moon from 2000–2015. Finally, time series analysis is applied to potential DCC albedo corrected Terra data. This shows it is capable of beginning the narrowing of cloud climate forcing uncertainty before 2015; some twenty five years sooner than previously calculated elsewhere, for missions yet to launch. earth radiation budget; MODIS; earth observation; lunar calibration; MERBE; climate observing system; deep convective cloud (DCC) albedo; solar forcing
Mayer, Johannes; Mayer, Michael; Haimberger, Leopold; Liu, ChunleiMayer, J., M. Mayer, L. Haimberger, C. Liu, 2022: Comparison of Surface Energy Fluxes from Global to Local Scale. J. Climate, 35(14), 4551-4569. doi: 10.1175/JCLI-D-21-0598.1. Abstract This study uses the ECMWF ERA5 reanalysis and observationally constrained top-of-the-atmosphere radiative fluxes to infer net surface energy fluxes covering 1985–2018, which can be further adjusted to match the observed mean land heat uptake. Various diagnostics are applied to provide error estimates of inferred fluxes on different spatial scales. For this purpose, adjusted as well as unadjusted inferred surface fluxes are compared with other commonly used flux products. On a regional scale, the oceanic energy budget of the North Atlantic between the RAPID array at 26.5°N and moorings located farther north (e.g., at the Greenland–Scotland Ridge) is evaluated. On the station scale, a comprehensive comparison of inferred and buoy-based fluxes is presented. Results indicate that global land and ocean averages of unadjusted inferred surface fluxes agree with the observed heat uptake to within 1 W m−2, while satellite-derived and model-based fluxes show large global mean biases. Furthermore, the oceanic energy budget of the North Atlantic is closed to within 2.7 (−0.2) W m−2 for the period 2005–09 when unadjusted (adjusted) inferred surface fluxes are employed. Indirect estimates of the 2004–16 mean oceanic heat transport at 26.5°N are 1.09 PW (1.17 PW with adjusted fluxes), which agrees well with observed RAPID transports. On the station scale, inferred fluxes exhibit a mean bias of −20.1 W m−2 when using buoy-based fluxes as reference, which confirms expectations that biases increase from global to local scales. However, buoy-based fluxes as reference are debatable, and are likely positively biased, suggesting that the station-scale bias of inferred fluxes is more likely on the order of −10 W m−2.
Mazhar, Usman; Jin, Shuanggen; Hu, Ting; Bilal, Muhammad; Ali, MD Arfan; Atique, LuqmanMazhar, U., S. Jin, T. Hu, M. Bilal, M. A. Ali, L. Atique, 2022: Long-time Variation and Mechanism of Surface Energy Budget over Diverse Geographical Regions in Pakistan. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 1-13. doi: 10.1109/JSTARS.2022.3185177. Earth's Energy budget is a major force that drives global climate. The long-term pattern of land surface energy budget with pronounced biophysical effects on climate was normally ignored at a regional scale, particularly in Pakistan. In this paper, the land surface energy budget from 2001 to 2018 was estimated and analyzed from Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud and the Earth's Radiant Energy System (CERES) observations over three geographical regions (Northern highlands, Indus plains and Baluchistan plateau) in Pakistan. Biophysical and energy budget parameters such as Land Surface Temperature (LST), albedo, emissivity, and Normalized Difference Vegetation Index (NDVI) were obtained from MODIS, while the downward shortwave solar and longwave thermal radiation were obtained from CERES satellite data. Spatiotemporal trends of three energy budget parameters: net radiation, latent heat flux and sensible heat flux, and three biophysical parameters, albedo, NDVI and LST, were investigated from 2001 to 2018. The latent heat flux showed a significant increase with a trend of 0.24, while a decrease in sensible heat flux with a trend of−0.21 was observed over Pakistan. Net radiation showed an ignorable increase with a trend of 0.054 over whole Pakistan. A significant negative relation was found between net radiation and sensible heat flux with albedo while a significant positive relation was found between latent heat flux and NDVI. Biophysical parameters such as NDVI, albedo and LST successively explain the trends of radiative and non-radiative fluxes. This study comprehensively explains the mechanism and patterns of the regional energy budget. Land surface; CERES; Meteorology; MODIS; Land surface temperature; Net radiation; Heating systems; and Pakistan; IP networks; Land surface Energy budget; Spatiotemporal phenomena
McCoy, Daniel T.; Field, Paul; Frazer, Michelle E.; Zelinka, Mark D.; Elsaesser, Gregory S; Mülmenstädt, Johannes; Tan, Ivy; Myers, Timothy A.; Lebo, Zachary J.McCoy, D. T., P. Field, M. E. Frazer, M. D. Zelinka, G. S. Elsaesser, J. Mülmenstädt, I. Tan, T. A. Myers, Z. J. Lebo, 2022: Extratropical shortwave cloud feedbacks in the context of the global circulation and hydrological cycle. Geophysical Research Letters, n/a(n/a), e2021GL097154. doi: 10.1029/2021GL097154. Shortwave (SW) cloud feedback (SWFB) is the primary driver of uncertainty in the effective climate sensitivity (ECS) predicted by global climate models (GCMs). ECS for several GCMs participating in the sixth assessment report exceed 5K, above the fifth assessment report ‘likely’ maximum (4.5K) due to extratropical SWFB’s that are more positive than those simulated in the previous generation of GCMs. Here we show that across 57 GCMs Southern Ocean SWFB can be predicted from the sensitivity of column-integrated liquid water mass (LWP) to moisture convergence and to surface temperature. The response of LWP to moisture convergence and the response of albedo to LWP anti-correlate across GCMs. This is because GCMs that simulate a larger response of LWP to moisture convergence tend to have higher mean-state LWPs, which reduces the impact of additional LWP on albedo. Observational constraints suggest a modestly negative Southern Ocean SWFB— inconsistent with extreme ECS. Feedback; Moisture; Clouds; Climate; Simulations
Miyamoto, Ayumu; Nakamura, Hisashi; Miyasaka, Takafumi; Kosaka, YuMiyamoto, A., H. Nakamura, T. Miyasaka, Y. Kosaka, 2022: Wintertime Weakening of Low-Cloud Impacts on the Subtropical High in the South Indian Ocean. J. Climate, 35(1), 323-334. doi: 10.1175/JCLI-D-21-0178.1. Abstract To elucidate the unique seasonality in the coupled system of the subtropical Mascarene high and low-level clouds, the present study compares wintertime cloud radiative impacts on the high with their summertime counterpart through coupled and atmospheric general circulation model simulations. A comparison of a fully coupled control simulation with another simulation in which the radiative effects of low-level clouds are artificially switched off demonstrates that the low-cloud effect on the formation of the Mascarene high is much weaker in winter. Background climatology plays an important role in this seasonality of the Mascarene high reinforcement. Relative to summer, the suppression of deep convection due to low-level clouds that acts to reinforce the high is much weaker in winter. This arises from 1) seasonally lower sea surface temperature in concert with the smaller sea surface temperature reduction due to the deeper ocean mixed layer and the weaker cloud radiative effect under weaker insolation and 2) seasonally stronger subtropical subsidence associated with the Hadley circulation in winter. As verified through atmospheric dynamical model experiments, enhanced cloud-top radiative cooling by low-level clouds acts to reinforce the wintertime Mascarene high in comparable magnitude as in summer. The present study reveals that the self-sustaining feedback with low-level clouds alone is insufficient for replenishing the full strength of the wintertime Mascarene high. This implies that another internal feedback pathway and/or external driver must be operative in maintaining the wintertime high.
Nugent, J. M.; Turbeville, S. M.; Bretherton, C. S.; Blossey, P. N.; Ackerman, T. P.Nugent, J. M., S. M. Turbeville, C. S. Bretherton, P. N. Blossey, T. P. Ackerman, 2022: Tropical Cirrus in Global Storm-Resolving Models: 1. Role of Deep Convection. Earth and Space Science, 9(2), e2021EA001965. doi: 10.1029/2021EA001965. Pervasive cirrus clouds in the upper troposphere and tropical tropopause layer (TTL) influence the climate by altering the top-of-atmosphere radiation balance and stratospheric water vapor budget. These cirrus are often associated with deep convection, which global climate models must parameterize and struggle to accurately simulate. By comparing high-resolution global storm-resolving models from the Dynamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) intercomparison that explicitly simulate deep convection to satellite observations, we assess how well these models simulate deep convection, convectively generated cirrus, and deep convective injection of water into the TTL over representative tropical land and ocean regions. The DYAMOND models simulate deep convective precipitation, organization, and cloud structure fairly well over land and ocean regions, but with clear intermodel differences. All models produce frequent overshooting convection whose strongest updrafts humidify the TTL and are its main source of frozen water. Intermodel differences in cloud properties and convective injection exceed differences between land and ocean regions in each model. We argue that, with further improvements, global storm-resolving models can better represent tropical cirrus and deep convection in present and future climates than coarser-resolution climate models. To realize this potential, they must use available observations to perfect their ice microphysics and dynamical flow solvers. convection; microphysics; cirrus; tropical tropopause layer; DYAMOND; global storm-resolving models
Nuncio, M.; Satheesan, K.; Acharya, Asutosh; Chatterjee, Sourav; Subeesh, M. P.; Athulya, R.Nuncio, M., K. Satheesan, A. Acharya, S. Chatterjee, M. P. Subeesh, R. Athulya, 2022: A southerly wind event and precipitation in Ny Ålesund, Arctic. Journal of Atmospheric and Solar-Terrestrial Physics, 231, 105869. doi: 10.1016/j.jastp.2022.105869. Precipitation in the Arctic is expected to increase with implications to ecosystems and changes to atmospheric circulation. In the Arctic strong southerly wind, often known as atmospheric rivers, supply enormous moisture and heat into the Arctic and is expected to increase in future warming scenarios. The impact of these events on Arctic climate change is not yet understood fully. In this study precipitation associated with such an event is studied for Ny Ålesund, Svalbard for 2016 March. During the event, the high precipitation was noticed between 22 and 23 UTC and 6–9 UTC on 12th March and 13th March respectively. It has been shown that during these two time periods, downwelling longwave radiation increased due to clouds. The enhanced downwelling longwave radiation increased the surface temperature locally. Above the shallow planetary boundary, advection dominated the temperature changes and initiated a shallow convection in the atmosphere leading to intensified precipitation in the lower layers during the event. Enhanced vertical velocity in MRR could be a result of this convection. Thus, the largescale southerly winds, that developed into an atmospheric river has not only contributed to the supply of heat and moisture but also enhanced cloud radiative effects and resulted in local warming. The moisture sources for this event appears to be Norwegian Sea and the east coast of Greenland. The scenario we have investigated was characterised by a warm Arctic with southerly warm winds. Studies suggest that convective scale precipitation is increasing in Eurasia under warm conditions. Our study points to the change in precipitation regime that Arctic may characterise as the warming continues. Cloud radiative effects; Arctic precipitation; Atmospheric river
Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Lebsock, Matthew; Zhang, ZhiboOreopoulos, L., N. Cho, D. Lee, M. Lebsock, Z. Zhang, 2022: Assessment of Two Stochastic Cloud Subcolumn Generators Using Observed Fields of Vertically Resolved Cloud Extinction. J. Atmos. Oceanic Technol., 39(8), 1229-1244. doi: 10.1175/JTECH-D-21-0166.1. Abstract We evaluate two stochastic subcolumn generators used in GCMs to emulate subgrid cloud variability enabling comparisons with satellite observations and simulations of certain physical processes. Our evaluation necessitated the creation of a reference observational dataset that resolves horizontal and vertical cloud variability. The dataset combines two CloudSat cloud products that resolve two-dimensional cloud optical depth variability of liquid, ice, and mixed-phase clouds when blended at ∼200 m vertical and ∼2 km horizontal scales. Upon segmenting the dataset to individual “scenes,” mean profiles of the cloud fields are passed as input to generators that produce scene-level cloud subgrid variability. The assessment of generator performance at the scale of individual scenes and in a mean sense is largely based on inferred joint histograms that partition cloud fraction within predetermined combinations of cloud-top pressure–cloud optical thickness ranges. Our main finding is that both generators tend to underestimate optically thin clouds, while one of them also tends to overestimate some cloud types of moderate and high optical thickness. Associated radiative flux errors are also calculated by applying a simple transformation to the cloud fraction histogram errors, and are found to approach values almost as high as 3 W m−2 for the cloud radiative effect in the shortwave part of the spectrum. Significance Statement The purpose of the paper is to assess the realism of relatively simple ways of producing fine-scale cloud variability in global models from coarsely resolved cloud properties. The assessment is achieved via comparisons to observed cloud fields where the fine-scale variability is known in both the horizontal and vertical directions. Our results show that while the generators have considerable skill, they still suffer from consistent deficiencies that need to be addressed with further development guided by appropriate observations.
Paca, Victor Hugo da Motta; Espinoza-Dávalos, Gonzalo E.; da Silva, Rodrigo; Tapajós, Raphael; dos Santos Gaspar, Avner BrasileiroPaca, V. H. d. M., G. E. Espinoza-Dávalos, R. da Silva, R. Tapajós, A. B. dos Santos Gaspar, 2022: Remote Sensing Products Validated by Flux Tower Data in Amazon Rain Forest. Remote Sensing, 14(5), 1259. doi: 10.3390/rs14051259. This work compares methods of climate measurements, such as those used to measure evapotranspiration, precipitation, net radiation, and temperature. The satellite products used were compared and evaluated against flux tower data. Evapotranspiration was validated against the SSEBop monthly and GLEAM daily and monthly products, respectively, and the results were RMSE = 24.144 mm/month, NRMSE = 0.223, r2 = 0.163, slope = 0.411; RMSE = 1.781 mm/day, NRMSE = 0.599, r2 = 0.000, slope = 0.006; RMSE = 36.17 mm/month, NRMSE = 0.401, r2 = 0.002, and slope = 0.026. Precipitation was compared with the CHIRPS data, K67 was not part of the CHIRPS station correction. The results for both the daily and monthly comparisons were RMSE = 18.777 mm/day, NRMSE = 1.027, r2 = 0.086, slope = 0.238 and RMSE = 130.713 mm/month, NRMSE = 0.706, r2 = 0.402, and slope = 0.818. The net radiation validated monthly with CERES was RMSE = 75.357 W/m2, NRMSE = 0.383, r2 = 0.422, and slope = 0.867. The temperature results, as compared to MOD11C3, were RMSE = 2.829 °C, NRMSE = 0.116, r2 = 0.153, and slope = 0.580. Comparisons between the remote sensing products and validation against the ground data were performed on a monthly basis. GLEAM and CHIRPS daily were the data sets with considerable discrepancy. comparison and validation; hydro-meteorological variables; remote sensing products
Peng, Liran; Pritchard, Michael; Hannah, Walter M.; Blossey, Peter N.; Worley, Patrick H; Bretherton, Christopher S.Peng, L., M. Pritchard, W. M. Hannah, P. N. Blossey, P. H. Worley, C. S. Bretherton, 2022: Load-balancing intense physics calculations to embed regionalized high-resolution cloud resolving models in the E3SM and CESM climate models. Journal of Advances in Modeling Earth Systems, n/a(n/a), e2021MS002841. doi: 10.1029/2021MS002841. We design a new strategy to load-balance high-intensity sub-grid atmospheric physics calculations restricted to a small fraction of a global climate simulation’s domain. We show why the current parallel load balancing infrastructure of CESM and E3SM cannot efficiently handle this scenario at large core counts. As an example, we study an unusual configuration of the E3SM Multiscale Modeling Framework (MMF) that embeds a binary mixture of two separate cloud-resolving model grid structures that is attractive for low cloud feedback studies. Less than a third of the planet uses high-resolution (MMF-HR; sub-km horizontal grid spacing) relative to standard low-resolution (MMF-LR) cloud superparameterization elsewhere. To enable MMF runs with Multi-Domain CRMs, our load balancing theory predicts the most efficient computational scale as a function of the high-intensity work’s relative overhead and its fractional coverage. The scheme successfully maximizes model throughput and minimizes model cost relative to precursor infrastructure, effectively by devoting the vast majority of the processor pool to operate on the few high-intensity (and rate-limiting) HR grid columns. Two examples prove the concept, showing that minor artifacts can be introduced near the HR/LR CRM grid transition boundary on idealized aquaplanets, but are minimal in operationally relevant real-geography settings. As intended, within the high (low) resolution area, our Multi-Domain CRM simulations exhibit cloud fraction and shortwave reflection convergent to standard baseline tests that use globally homogenous MMF-LR and MMF-HR. We suggest this approach can open up a range of creative multi-resolution climate experiments without requiring unduly large allocations of computational resources.
Quaas, Johannes; Jia, Hailing; Smith, Chris; Albright, Anna Lea; Aas, Wenche; Bellouin, Nicolas; Boucher, Olivier; Doutriaux-Boucher, Marie; Forster, Piers M.; Grosvenor, Daniel; Jenkins, Stuart; Klimont, Zig; Loeb, Norman G.; Ma, Xiaoyan; Naik, Vaishali; Paulot, Fabien; Stier, Philip; Wild, Martin; Myhre, Gunnar; Schulz, MichaelQuaas, J., H. Jia, C. Smith, A. L. Albright, W. Aas, N. Bellouin, O. Boucher, M. Doutriaux-Boucher, P. M. Forster, D. Grosvenor, S. Jenkins, Z. Klimont, N. G. Loeb, X. Ma, V. Naik, F. Paulot, P. Stier, M. Wild, G. Myhre, M. Schulz, 2022: Robust evidence for reversal in the aerosol effective climate forcing trend. Atmospheric Chemistry and Physics Discussions, 1-25. doi: 10.5194/acp-2022-295. Abstract. Anthropogenic aerosols exert a cooling influence that offsets part of the greenhouse gas warming. Due to their short tropospheric lifetime of only up to several days, the aerosol forcing responds quickly to emissions. Here we present and discuss the evolution of the aerosol forcing since 2000. There are multiple lines of evidence that allow to robustly conclude that the anthropogenic aerosol effective radiative forcing – both aerosol-radiation and aerosol-cloud interactions – has become globally less negative, i.e. that the trend in aerosol effective radiative forcing changed sign from negative to positive. Bottom-up inventories show that anthropogenic primary aerosol and aerosol precursor emissions declined in most regions of the world; observations related to aerosol burden show declining trends, in particular of the fine-mode particles that make up most of the anthropogenic aerosols; satellite retrievals of cloud droplet numbers show trends consistent in sign, as do observations of top-of-atmosphere radiation. Climate model results, including a revised set that is constrained by observations of the ocean heat content evolution show a consistent sign and magnitude for a positive forcing relative to 2000 due to reduced aerosol effects. This reduction leads to an acceleration of the forcing of climate change, i.e. an increase in forcing by 0.1 to 0.3 W m-2, up to 12 % of the total climate forcing in 2019 compared to 1750 according to IPCC.
Ramesh, Nandini; Boos, William R.Ramesh, N., W. R. Boos, 2022: The Unexpected Oceanic Peak in Energy Input to the Atmosphere and Its Consequences for Monsoon Rainfall. Geophysical Research Letters, 49(12), e2022GL099283. doi: 10.1029/2022GL099283. Monsoons have historically been understood to be caused by the low thermal inertia of land, allowing more energy from summer insolation to be transferred to the overlying atmosphere than over adjacent ocean. Here, we show that during boreal summer, the global maximum net energy input (NEI) to the atmosphere unexpectedly lies over the Indian Ocean, not over land. Observed radiative fluxes suggest that cloud-radiative effects (CRE) almost double the NEI over ocean, shifting the NEI peak from land to ocean. Global climate model experiments with both land and interactive sea surface temperatures confirm that CRE create the oceanic NEI maximum. Interactions between CRE, NEI, circulation, and land-sea contrast in surface heat capacity shift precipitation from Southeast to South Asia. CRE thus alter the global partitioning of precipitation between land and ocean and the spatial structure of Earth's strongest monsoon, in ways that can be understood through the NEI. cloud radiative effects; monsoons; atmospheric dynamics; land-sea contrast; tropical climate
Ramos, R. D.; LeGrande, A. N.; Griffiths, M. L.; Elsaesser, G. S.; Litchmore, D. T.; Tierney, J. E.; Pausata, F. S. R.; Nusbaumer, J.Ramos, R. D., A. N. LeGrande, M. L. Griffiths, G. S. Elsaesser, D. T. Litchmore, J. E. Tierney, F. S. R. Pausata, J. Nusbaumer, 2022: Constraining Clouds and Convective Parameterizations in a Climate Model Using Paleoclimate Data. Journal of Advances in Modeling Earth Systems, 14(8), e2021MS002893. doi: 10.1029/2021MS002893. Cloud and convective parameterizations strongly influence uncertainties in equilibrium climate sensitivity. We provide a proof-of-concept study to constrain these parameterizations in a perturbed parameter ensemble of the atmosphere-only version of the Goddard Institute for Space Studies Model E2.1 simulations by evaluating model biases in the present-day runs using multiple satellite climatologies and by comparing simulated δ18O of precipitation (δ18Op), known to be sensitive to parameterization schemes, with a global database of speleothem δ18O records covering the Last Glacial Maximum (LGM), mid-Holocene (MH) and pre-industrial (PI) periods. Relative to modern interannual variability, paleoclimate simulations show greater sensitivity to parameter changes, allowing for an evaluation of model uncertainties over a broader range of climate forcing and the identification of parts of the world that are parameter sensitive. Certain simulations reproduced absolute δ18Op values across all time periods, along with LGM and MH δ18Op anomalies relative to the PI, better than the default parameterization. No single set of parameterizations worked well in all climate states, likely due to the non-stationarity of cloud feedbacks under varying boundary conditions. Future work that involves varying multiple parameter sets simultaneously with coupled ocean feedbacks will likely provide improved constraints on cloud and convective parameterizations. PPE; cloud and convective parameterization; paleoclimate model; proxy-model comparison; speleothem; water isotopes
Ren, Tong; Yang, Ping; Wei, Jian; Huang, Xianglei; Sang, HuiyanRen, T., P. Yang, J. Wei, X. Huang, H. Sang, 2022: Performance of Cloud 3D Solvers in Ice Cloud Shortwave Radiation Closure Over the Equatorial Western Pacific Ocean. Journal of Advances in Modeling Earth Systems, 14(2), e2021MS002754. doi: 10.1029/2021MS002754. For retrieving cloud optical properties from satellite images or computing these properties from climate model output, computationally efficient treatments of cloud horizontal inhomogeneity include the Monte Carlo Independent Column Approximation (McICA) and the Tripleclouds method. Computationally efficient treatment of cloud horizontal radiation exchanges includes the SPeedy Algorithm for Radiative TrAnsfer through CloUd Sides (SPARTACUS). As a test to derive properties from satellite images, we collocate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud retrievals with near-nadir Cloud and the Earth's Radiant Energy System (CERES) footprints in July 2008 over an equatorial western Pacific Ocean region to compare the performance of the McICA, Tripleclouds, and SPARTACUS solvers to the conventional plane-parallel homogeneous (PPH) treatment. PPH overestimates cloud albedo, and the three solvers effectively reduce overestimation with root mean square error of shortwave upwelling irradiance decreasing between 15.72 and 18.53 W m−2, or about 22%–25%. Although cloud top variability does not get fed into the simulations, all three solvers also reduce the effect of cloud top variability on cloud albedo. Entrapment (energy reflected downward from clouds) and horizontal radiation transfer have opposite effects on the SPARTACUS cloud albedo simulation. The net effect depends on the cloud vertical extent, the unawareness of which limits the performance of the SPARTACUS solver. cloud 3D effect; cloud top variability; cloud vertical extent
Russotto, Rick D.; Strong, Jeffrey D. O.; Camargo, Suzana J.; Sobel, Adam; Elsaesser, Gregory S.; Kelley, Maxwell; Del Genio, Anthony; Moon, Yumin; Kim, DaehyunRussotto, R. D., J. D. O. Strong, S. J. Camargo, A. Sobel, G. S. Elsaesser, M. Kelley, A. Del Genio, Y. Moon, D. Kim, 2022: Evolution of Tropical Cyclone Properties Across the Development Cycle of the GISS-E3 Global Climate Model. Journal of Advances in Modeling Earth Systems, 14(1), e2021MS002601. doi: 10.1029/2021MS002601. The next-generation global climate model from the NASA Goddard Institute for Space Studies, GISS-E3, contains many improvements to resolution and physics that allow for improved representation of tropical cyclones (TCs) in the model. This study examines the properties of TCs in two different versions of E3 at different points in its development cycle, run for 20 years at 0.5° resolution, and compares these TCs with observations, the previous generation GISS model, E2, and other climate models. E3 shares many TC biases common to global climate models, such as having too few tropical cyclones, but is much improved from E2. E3 produces strong enough TCs that observation-based wind speed thresholds can now be used to detect and track them, and some storms now reach hurricane intensity; neither of these was true of E2. Model development between the first and second versions of E3 further increased the number and intensity of TCs and reduced TC count biases globally and in most regions. One-year sensitivity tests to changes in various microphysical and dynamical tuning parameters are also examined. Increasing the entrainment rate for the more strongly entraining plume in the convection scheme increases the number of TCs (though also affecting other climate variables, and in some cases increasing biases). Variations in divergence damping did not have a strong effect on simulated TC properties, contrary to expectations based on previous studies. Overall, the improvements in E3 make it more credible for studies of TC activity and its relationship to climate. tropical meteorology; climate model; tropical cyclones; hurricanes
Săftoiu, G; Stefan, Sabina; Antonescu, B; Iorga, Gabriela; Belegante, LSăftoiu, G., S. Stefan, B. Antonescu, G. Iorga, L. Belegante, 2022: CHARACTERISTICS OF STRATOCUMULUS CLOUDS OVER BUCHAREST-MĂGURELE. Romanian Reports in Physics, 74. Stratocumulus clouds represent one of the key components of the Earth's radiative balance because it generally reflects incident solar radiation. The aim of the study is to understand the occurrence and characteristics of stratocumulus clouds using satellite data collected from Dec 2019 to Feb 2021. A series of macrophysically and microphysical cloud parameters (cloud cover fraction, cloud types, cloud geometrical depth, cloud top temperature, cloud top pressure, cloud height, cloud optical depth, liquid water path) were extracted from the Clouds and the Earth's Radiant Energy System (CERES) database for a region in south west Bucharest, were the Măgurele Center for Atmosphere and Radiation Studies (MARS) is located.
Salzmann, M.; Ferrachat, S.; Tully, C.; Münch, S.; Watson-Parris, D.; Neubauer, D.; Siegenthaler-Le Drian, C.; Rast, S.; Heinold, B.; Crueger, T.; Brokopf, R.; Mülmenstädt, J.; Quaas, J.; Wan, H.; Zhang, K.; Lohmann, U.; Stier, P.; Tegen, I.Salzmann, M., S. Ferrachat, C. Tully, S. Münch, D. Watson-Parris, D. Neubauer, C. Siegenthaler-Le Drian, S. Rast, B. Heinold, T. Crueger, R. Brokopf, J. Mülmenstädt, J. Quaas, H. Wan, K. Zhang, U. Lohmann, P. Stier, I. Tegen, 2022: The Global Atmosphere-aerosol Model ICON-A-HAM2.3–Initial Model Evaluation and Effects of Radiation Balance Tuning on Aerosol Optical Thickness. Journal of Advances in Modeling Earth Systems, 14(4), e2021MS002699. doi: 10.1029/2021MS002699. The Hamburg Aerosol Module version 2.3 (HAM2.3) from the ECHAM6.3-HAM2.3 global atmosphere-aerosol model is coupled to the recently developed icosahedral nonhydrostatic ICON-A (icon-aes-1.3.00) global atmosphere model to yield the new ICON-A-HAM2.3 atmosphere-aerosol model. The ICON-A and ECHAM6.3 host models use different dynamical cores, parameterizations of vertical mixing due to sub-grid scale turbulence, and parameter settings for radiation balance tuning. Here, we study the role of the different host models for simulated aerosol optical thickness (AOT) and evaluate impacts of using HAM2.3 and the ECHAM6-HAM2.3 two-moment cloud microphysics scheme on several meteorological variables. Sensitivity runs show that a positive AOT bias over the subtropical oceans is remedied in ICON-A-HAM2.3 because of a different default setting of a parameter in the moist convection parameterization of the host models. The global mean AOT is biased low compared to MODIS satellite instrument retrievals in ICON-A-HAM2.3 and ECHAM6.3-HAM2.3, but the bias is larger in ICON-A-HAM2.3 because negative AOT biases over the Amazon, the African rain forest, and the northern Indian Ocean are no longer compensated by high biases over the sub-tropical oceans. ICON-A-HAM2.3 shows a moderate improvement with respect to AOT observations at AERONET sites. A multivariable bias score combining biases of several meteorological variables into a single number is larger in ICON-A-HAM2.3 compared to standard ICON-A and standard ECHAM6.3. In the tropics, this multivariable bias is of similar magnitude in ICON-A-HAM2.3 and in ECHAM6.3-HAM2.3. In the extra-tropics, a smaller multivariable bias is found for ICON-A-HAM2.3 than for ECHAM6.3-HAM2.3. modeling; aerosol
Shaw, J.; McGraw, Z.; Bruno, O.; Storelvmo, T.; Hofer, S.Shaw, J., Z. McGraw, O. Bruno, T. Storelvmo, S. Hofer, 2022: Using Satellite Observations to Evaluate Model Microphysical Representation of Arctic Mixed-Phase Clouds. Geophysical Research Letters, 49(3), e2021GL096191. doi: 10.1029/2021GL096191. Mixed-phase clouds play an important role in determining Arctic warming, but are parametrized in models and difficult to constrain with observations. We use two satellite-derived cloud phase metrics to investigate the vertical structure of Arctic clouds in two global climate models that use the Community Atmosphere Model version 6 (CAM6) atmospheric component. We report a model error limiting ice nucleation, produce a set of Arctic-constrained model runs by adjusting model microphysical variables to match the cloud phase metrics, and evaluate cloud feedbacks for all simulations. Models in this small ensemble uniformly overestimate total cloud fraction in the summer, but have variable representation of cloud fraction and phase in the winter and spring. By relating modeled cloud phase metrics and changes in low-level liquid cloud amount under warming to longwave cloud feedback, we show that mixed-phase processes mediate the Arctic climate by modifying how wintertime and springtime clouds respond to warming. climate models; cloud feedback; satellite; ice nucleation; Arctic amplificantion
Shi, Yang; Liu, Xiaohong; Wu, Mingxuan; Zhao, Xi; Ke, Ziming; Brown, HunterShi, Y., X. Liu, M. Wu, X. Zhao, Z. Ke, H. Brown, 2022: Relative importance of high-latitude local and long-range-transported dust for Arctic ice-nucleating particles and impacts on Arctic mixed-phase clouds. Atmospheric Chemistry and Physics, 22(4), 2909-2935. doi: 10.5194/acp-22-2909-2022. Abstract. Dust particles, serving as ice-nucleating particles (INPs), may impact the Arctic surface energy budget and regional climate by modulating the mixed-phase cloud properties and lifetime. In addition to long-range transport from low-latitude deserts, dust particles in the Arctic can originate from local sources. However, the importance of high-latitude dust (HLD) as a source of Arctic INPs (compared to low-latitude dust, LLD) and its effects on Arctic mixed-phase clouds are overlooked. In this study, we evaluate the contribution to Arctic dust loading and INP population from HLD and six LLD source regions by implementing a source-tagging technique for dust aerosols in version 1 of the US Department of Energy's Energy Exascale Earth System Model (E3SMv1). Our results show that HLD is responsible for 30.7 % of the total dust burden in the Arctic, whereas LLD from Asia and North Africa contributes 44.2 % and 24.2 %, respectively. Due to its limited vertical transport as a result of stable boundary layers, HLD contributes more in the lower troposphere, especially in boreal summer and autumn when the HLD emissions are stronger. LLD from North Africa and East Asia dominates the dust loading in the upper troposphere with peak contributions in boreal spring and winter. The modeled INP concentrations show better agreement with both ground and aircraft INP measurements in the Arctic when including HLD INPs. The HLD INPs are found to induce a net cooling effect (−0.24 W m−2 above 60∘ N) on the Arctic surface downwelling radiative flux by changing the cloud phase of the Arctic mixed-phase clouds. The magnitude of this cooling is larger than that induced by North African and East Asian dust (0.08 and −0.06 W m−2, respectively), mainly due to different seasonalities of HLD and LLD. Uncertainties of this study are discussed, which highlights the importance of further constraining the HLD emissions.
Shukla, Abhivyakti; Pattnaik, Sandeep; Trivedi, DhananjayShukla, A., S. Pattnaik, D. Trivedi, 2022: Study of Mesoscale Convective System and its Associated Cloud Structure over Indian Region Using Satellite Observations and Model Simulations. Journal of the Indian Society of Remote Sensing. doi: 10.1007/s12524-022-01573-0. The present study has discussed the identification of mesoscale convective systems (MCS) events using Cloud top temperatures from Cloud and the Earth’s Radiant Energy System and INSAT 3D imageries over the Indian region. The parameters such as height, areal extent, and vertical depth are considered as the criteria for identifying these intense rain-bearing MCS. High equivalent potential temperature, pronounced warm advection, low-level convergence, and local maximum in relative vorticity is associated with large-scale environments are the key indicators in identifying MCS. A total of five heavy rainfall events associated with MCS are simulated using the Weather Research and forecasting at a horizontal resolution of 3 km with a lead time of up to 96 h. In addition, the performance of two cumulus and four cloud microphysical parameterizations and their optimized combination are investigated for these MCS systems causing heavy rainfall over the region. The Betts–Miller–Janjic–Thompson combination simulated the best results in terms of rainfall, convective available potential energy, vertical updrafts, and reflectivity and its pre-formation environment of MCS. Further, this optimized combination is able to accurately represent the dominant hydrometeors (i.e., rain, graupel and snow), which have played a key role in simulating the MCS. Large-scale forcing such as moisture advection, convergence, relative vorticity, and equivalent potential temperature play a dominant role in the evolution and sustenance of MCS. Finally, a more robust (weaker) intensity MCS is better (poorly) predicted by the model. The findings of this study will further augment our understanding for better prediction of MCS associated with heavy rainfall events over the Indian region. Hydrometeors; Mesoscale convective system (MCS); WRF-ARW
Simonetti, Paolo; Vladilo, Giovanni; Silva, Laura; Maris, Michele; Ivanovski, Stavro L.; Biasiotti, Lorenzo; Malik, Matej; Hardenberg, Jost vonSimonetti, P., G. Vladilo, L. Silva, M. Maris, S. L. Ivanovski, L. Biasiotti, M. Malik, J. v. Hardenberg, 2022: EOS: Atmospheric Radiative Transfer in Habitable Worlds with HELIOS. The Astrophysical Journal, 925(2), 105. doi: 10.3847/1538-4357/ac32ca. We present EOS, a procedure for determining the outgoing longwave radiation (OLR) and top-of-atmosphere (TOA) albedo for a wide range of conditions expected to be present in the atmospheres of rocky planets with temperate conditions. EOS is based on HELIOS and HELIOS-K, which are novel and publicly available atmospheric radiative transfer (RT) codes optimized for fast calculations with GPU processors. These codes were originally developed for the study of giant planets. In this paper we present an adaptation for applications to terrestrial-type, habitable planets, adding specific physical recipes for the gas opacity and vertical structure of the atmosphere. To test the reliability of the procedure, we assessed the impact of changing line opacity profile, continuum opacity model, atmospheric lapse rate, and tropopause position prescriptions on the OLR and the TOA albedo. The results obtained with EOS are in line with those of other RT codes running on traditional CPU processors, while being at least one order of magnitude faster. The adoption of OLR and TOA albedo data generated with EOS in a zonal and seasonal climate model correctly reproduces the fluxes of the present-day Earth measured by the CERES spacecraft. The results of this study disclose the possibility to incorporate fast RT calculations in climate models aimed at characterizing the atmospheres of habitable exoplanets.
Singh, Sachchidanand; Mishra, Amit Kumar; Jose, Sandhya; Lodhi, Neelesh K.Singh, S., A. K. Mishra, S. Jose, N. K. Lodhi, 2022: Chapter 7 - Atmospheric pollution and solar ultraviolet radiation in Asia. Asian Atmospheric Pollution, 129-146. This chapter deals with atmospheric pollution, particularly the aerosol optical depth (AOD) and its impact on ultraviolet radiation flux reaching the Earth's surface, and its subsequent effect on vitamin D levels observed in the Asian region. It begins with the mean distribution during the last 16 years (2001–2016) of AOD, UVA, and UVB fluxes over Asia along with their trends on a 1°×1° grid scale. The Clouds and Earth Radiant Energy System (CERES) is the main source of data supported by data from MISR. High AOD values over Asia are well anticorrelated with the UVA and UVB fluxes reaching the surface. The reducing trend in UVB due to an increasing trend in AOD is a matter of concern, as UVB has a direct relation with the level of vitamin D prevalent in the Asian population, particularly in the South, Southeast Asian region. The accelerated economic development during the last two decades in Asia has led to an enhancement in AOD leading to a decrease in UVB reaching the surface and possibly reducing the production of vitamin D on a huge population in the region. Further targeted studies are however required to quantify the amount of reduction in vitamin D due to enhanced air pollution and AOD. CERES; Aerosol optical depth; MISR; Air pollution; UVA flux; UVB flux; Vitamin D
Sismanidis, Panagiotis; Bechtel, Benjamin; Perry, Mike; Ghent, DarrenSismanidis, P., B. Bechtel, M. Perry, D. Ghent, 2022: The Seasonality of Surface Urban Heat Islands across Climates. Remote Sensing, 14(10), 2318. doi: 10.3390/rs14102318. In this work, we investigate how the seasonal hysteresis of the Surface Urban Heat Island Intensity (SUHII) differs across climates and provide a detailed typology of the daytime and nighttime SUHII hysteresis loops. Instead of the typical tropical/dry/temperate/continental grouping, we describe Earth’s climate using the Köppen–Geiger system that empirically maps Earth’s biome distribution into 30 climate classes. Our thesis is that aggregating multi-city data without considering the biome of each city results in temporal means that fail to reflect the actual SUHII characteristics. This is because the SUHII is a function of both urban and rural features and the phenology of the rural surroundings can differ considerably between cities, even in the same climate zone. Our investigation covers all the densely populated areas of Earth and uses 18 years (2000–2018) of land surface temperature and land cover data from the European Space Agency’s Climate Change Initiative. Our findings show that, in addition to concave-up and -down shapes, the seasonal hysteresis of the SUHII also exhibits twisted, flat, and triangle-like patterns. They also suggest that, in wet climates, the daytime SUHII hysteresis is almost universally concave-up, but they paint a more complex picture for cities in dry climates. MODIS; LST; land surface temperature; ESA-CCI; Köppen–Geiger climate zones; seasonal hysteresis; SUHI; surface urban heat island
Södergren, A. H.; McDonald, A. J.Södergren, A. H., A. J. McDonald, 2022: Quantifying the Role of Atmospheric and Surface Albedo on Polar Amplification Using Satellite Observations and CMIP6 Model Output. Journal of Geophysical Research: Atmospheres, 127(12), e2021JD035058. doi: 10.1029/2021JD035058. Understanding polar amplification (PA) and its underlying processes is key to accurately predicting the climate system's response to increasing anthropogenic forcings. We examine the amplified warming in the Arctic and Antarctic in 17 global climate models from the Coupled Model Intercomparison Project 6 (CMIP6) against satellite data. Large hemispheric differences in PA strength was found in the CMIP6 models. Changes in surface temperature and strength of PA is closely coupled to changes in albedo. The planetary albedo of Earth (αp) is partitioned into a component associated with surface albedo (defined as surface contribution to planetary albedo, ), and a component associated with atmospheric albedo (atmospheric contribution to planetary albedo, ). To assess the hemispheric differences in PA strengths, the relative importance of and were investigated. The surface reflection looks different as seen at the surface (defined as surface albedo, αsurf) compared to (as seen at the top of the atmosphere). We find a stronger correlation between surface temperature and αsurf in the Arctic than in the Antarctic, with correlation coefficients of −0.94 and −0.88, respectively. Interestingly, the correlation for surface temperature and is stronger in the Antarctic than in the Arctic with correlation coefficients of −0.93 and −0.90, respectively. In the southern high latitudes, albedo changes at the surface are more important than changes in the atmosphere, while the opposite applies in the northern high latitudes. Surface temperature changes in the low- and mid-latitudes are strongly associated with changes in , dominated by changes in cloud properties. climate change; albedo; climate models; cmip6; polar amplification
Song, Yajuan; Qiao, Fangli; Liu, Jiping; Shu, Qi; Bao, Ying; Wei, Meng; Song, ZhenyaSong, Y., F. Qiao, J. Liu, Q. Shu, Y. Bao, M. Wei, Z. Song, 2022: Effects of Sea Spray on Large-Scale Climatic Features over the Southern Ocean. J. Climate, 35(14), 4645-4663. doi: 10.1175/JCLI-D-21-0608.1. Abstract The Southern Ocean, characterized by strong westerly winds and a rough sea state, exhibits the most pronounced sea spray effects. Sea spray ejected by ocean surface waves enhances heat and water exchange at the air–sea interface. However, this process has not been considered in current climate models, and the influence of sea spray on the coupled air–sea system remains largely unknown. This study incorporated a parameterization of the sea spray influence on latent and sensible heat fluxes into the First Institute of Oceanography Earth System Model version 2.0 (FIO-ESM v2.0), a climate model coupled with an ocean surface waves component. The results indicate that the spray-mediated enthalpy flux accounted for over 20%–50% of the total value. Sea spray promoted ocean evaporation and heat transport, resulting in air and ocean surface cooling and strengthened westerly winds. Furthermore, a moist and stable atmosphere favored an increase in cloud fraction over the Southern Ocean, particularly low-level clouds. Increased clouds reflected downward shortwave radiation and reduced solar radiation absorption at the surface. At present, the climate models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6) still suffer notable deficiencies in reasonably reproducing the climatological features of the Southern Ocean, including warm SST and underestimated clouds biases with more absorbed shortwave radiation. Our results suggest that consideration of sea spray effects is a feasible solution to mitigate these common biases and enhance the confidence in simulations and predictions with climate models.
Song, Zhen; Liang, Shunlin; Zhou, HongminSong, Z., S. Liang, H. Zhou, 2022: Top-of-Atmosphere Clear-Sky Albedo Estimation Over Ocean: Preliminary Framework for MODIS. IEEE Transactions on Geoscience and Remote Sensing, 60, 1-9. doi: 10.1109/TGRS.2021.3116620. Top-of-atmosphere (TOA) albedo is a significant factor of earth energy budget, climate change, and environmental change. As tremendous regional and global changes are happening over ocean, more details are needed to monitor the ocean environment. However, there were still no high-spatial resolution TOA albedo products over ocean. In this study, a new algorithm for clear-sky TOA albedo estimation over ocean was proposed, based on Moderate Resolution Imaging Spectroradiometer (MODIS) data. Instead of building angular distribution models, direct retrieval models between TOA reflectance and TOA albedo were developed based on extensive radiative transfer (RT) simulations, covering thousands of ocean and atmosphere types. Three-component ocean water albedo model was involved to take account for the ocean surface anisotropy at different wind speed, wind direction, and chlorophyll concentration, while Modtran 5 was utilized to simulate different atmospheric conditions. Our results showed good agreement with the Clouds and the Earth’s Radiant Energy System (CERES) based on a global comparison on August 4, 2011, with RMSE = 0.015 and bias = 0.002. And our MODIS-based products provide more spatial details due to higher spatial resolution (1 km), which will be a good data source for regional environmental and climatic research and will also enhance the understanding of Earth’s radiation budget. Earth; Oceans; Wind speed; MODIS; Atmospheric modeling; energy budget; Moderate Resolution Imaging Spectroradiometer (MODIS); Sea surface; Climate change; Broadband communication; ocean bidirectional reflectance distribution function (BRDF); radiative transfer (RT) simulations; top-of-atmosphere (TOA) albedo
Sreenath, A. V.; Abhilash, S.; Vijaykumar, P.; Mapes, B. E.Sreenath, A. V., S. Abhilash, P. Vijaykumar, B. E. Mapes, 2022: West coast India’s rainfall is becoming more convective. npj Climate and Atmospheric Science, 5(1), 1-7. doi: 10.1038/s41612-022-00258-2. A disastrous cloudburst and associated floods in Kerala during the 2019 monsoon season raise the hypothesis that rainfall over the west coast of India, much of which is stratiform, may be trending towards being more convective. As a first exploration, we sought statistically significant differences in monthly ERA-5 reanalysis data for the monsoon season between two epochs, 1980–1999 and 2000–2019. Results suggest a more convective (deeper, ice-rich) cloud population in recent decades, with patterns illustrated in ERA-5 spatial maps. Deepening of convection, above and beyond its trend in amount, is also indicated by the steeper regression slope of outgoing longwave radiation trends against precipitation than that exhibited in interannual variability. Our reanalysis results are strengthened by related trends manifested in more direct observations from satellite and gauge-based rainfall and a CAPE index from balloon soundings data. Attribution; Climate-change impacts
Srinivasan, Ashwanth; Chin, T. M.; Chassignet, E. P.; Iskandarani, M.; Groves, N.Srinivasan, A., T. M. Chin, E. P. Chassignet, M. Iskandarani, N. Groves, 2022: A Statistical Interpolation Code for Ocean Analysis and Forecasting. J. Atmos. Oceanic Technol., 39(3), 367-386. doi: 10.1175/JTECH-D-21-0033.1. Abstract We present a data assimilation package for use with ocean circulation models in analysis, forecasting, and system evaluation applications. The basic functionality of the package is centered on a multivariate linear statistical estimation for a given predicted/background ocean state, observations, and error statistics. Novel features of the package include support for multiple covariance models, and the solution of the least squares normal equations either using the covariance matrix or its inverse—the information matrix. The main focus of this paper, however, is on the solution of the analysis equations using the information matrix, which offers several advantages for solving large problems efficiently. Details of the parameterization of the inverse covariance using Markov random fields are provided and its relationship to finite-difference discretizations of diffusion equations are pointed out. The package can assimilate a variety of observation types from both remote sensing and in situ platforms. The performance of the data assimilation methodology implemented in the package is demonstrated with a yearlong global ocean hindcast with a 1/4° ocean model. The code is implemented in modern Fortran, supports distributed memory, shared memory, multicore architectures, and uses climate and forecasts compliant Network Common Data Form for input/output. The package is freely available with an open source license from www.tendral.com/tsis/.
Storto, Andrea; Cheng, Lijing; Yang, ChunxueStorto, A., L. Cheng, C. Yang, 2022: Revisiting the 2003–18 Deep Ocean Warming through Multiplatform Analysis of the Global Energy Budget. J. Climate, 35(14), 4701-4717. doi: 10.1175/JCLI-D-21-0726.1. Abstract Recent estimates of the global warming rates suggest that approximately 9% of Earth’s excess heat has been cumulated in the deep and abyssal oceans (below 2000-m depth) during the last two decades. Such estimates assume stationary trends deducted as long-term rates. To reassess the deep ocean warming and potentially shed light on its interannual variability, we formulate the balance between Earth’s energy imbalance (EEI), the steric sea level, and the ocean heat content (OHC), at yearly time scales during the 2003–18 period, as a variational problem. The solution is achieved through variational minimization, merging observational data from top-of-atmosphere EEI, inferred from Clouds and the Earth’s Radiant Energy System (CERES), steric sea level estimates from altimetry minus gravimetry, and upper-ocean heat content estimates from in situ platforms (mostly Argo floats). Global ocean reanalyses provide background-error covariances for the OHC analysis. The analysis indicates a 2000-m–bottom warming of 0.08 ± 0.04 W m−2 for the period 2003–18, equal to 13% of the total ocean warming (0.62 ± 0.08 W m−2), slightly larger than previous estimates but consistent within the error bars. The analysis provides a fully consistent optimized solution also for the steric sea level and EEI. Moreover, the simultaneous use of the different heat budget observing networks is able to decrease the analysis uncertainty with respect to the observational one, for all observation types and especially for the 0–700-m OHC and steric sea level (more than 12% reduction). The sensitivity of the analysis to the choice of the background time series proved insignificant. Significance Statement Several observing networks provide complementary information about the temporal evolution of the global energy budget. Here, satellite observations of Earth’s energy imbalance (EEI) and steric sea level and in situ–derived estimates of ocean heat content anomalies are combined in a variational analysis framework, with the goal of assessing the deep ocean warming. The optimized solution accounts for the uncertainty of the different observing networks. Furthermore, it provides fully consistent analyses of global ocean heat content, steric sea level, and EEI, which show smaller uncertainty than the original observed time series. The deep ocean (below 2000-m depth) exhibits a significant warming of 0.08 ± 0.04 W m−2 for the period 2003–18, equal to the 13% of the total ocean warming.
Subba, Tamanna; Gogoi, Mukunda M.; Moorthy, K. Krishna; Bhuyan, Pradip K.; Pathak, Binita; Guha, Anirban; Srivastava, Manoj Kumar; Vyas, B. M.; Singh, Karamjit; Krishnan, Jayabala; Lakshmi Kumar, T. V.; Babu, S. SureshSubba, T., M. M. Gogoi, K. K. Moorthy, P. K. Bhuyan, B. Pathak, A. Guha, M. K. Srivastava, B. M. Vyas, K. Singh, J. Krishnan, T. V. Lakshmi Kumar, S. S. Babu, 2022: New estimates of aerosol radiative effects over India from surface and satellite observations. Atmospheric Research, 276, 106254. doi: 10.1016/j.atmosres.2022.106254. Multi-year measurements of surface-reaching solar (shortwave) radiation fluxes across a network of aerosol observatories (ARFINET) are combined with concurrent satellite (CERES)-based top of the atmosphere (TOA) fluxes to estimate regional aerosol direct radiative forcing (ARF) over the Indian region. The synergistic approach improves the accuracy of ARF estimates, which otherwise results in an overestimation or underestimation of the atmospheric forcing. During summer, an overestimation of ~5 W m−2 (corresponding heating rate ~ 0.15 K day−1) is noticed. The regional average ARF from the synergistic approach reveals the surface forcing reaching −49 W m−2 over the Indo Gangetic Plains, −45 W m−2 over northeast India, −34 W m−2 over the southern Peninsula, and − 16 W m−2 in the oceanic regions of the Bay of Bengal. The ARF over the northern half of the Indian subcontinent is influenced mainly by anthropogenic sulfate and carbonaceous aerosols. Dust is dominant in the western region of India during MAM and JJAS. Overall, the clear sky surface reaching solar radiation fluxes is reduced by 3–22% due to the abundance of aerosols in the atmosphere, with the highest reduction over the IGP during autumn and winter. CERES; Heating rate; MERRA-2; ARFINET; SW-radiation; Aerosol composition; Aerosol radiative forcing
Sun, Moguo; Doelling, David R.; Loeb, Norman G.; Scott, Ryan C.; Wilkins, Joshua; Nguyen, Le Trang; Mlynczak, PamelaSun, M., D. R. Doelling, N. G. Loeb, R. C. Scott, J. Wilkins, L. T. Nguyen, P. Mlynczak, 2022: Clouds and the Earth’s Radiant Energy System (CERES) FluxByCldTyp Edition 4 Data Product. J. Atmos. Oceanic Technol., 39(3), 303-318. doi: 10.1175/JTECH-D-21-0029.1. Abstract The Clouds and the Earth’s Radiant Energy System (CERES) project has provided the climate community 20 years of globally observed top of the atmosphere (TOA) fluxes critical for climate and cloud feedback studies. The CERES Flux By Cloud Type (FBCT) product contains radiative fluxes by cloud type, which can provide more stringent constraints when validating models and also reveal more insight into the interactions between clouds and climate. The FBCT product provides 1° regional daily and monthly shortwave (SW) and longwave (LW) cloud-type fluxes and cloud properties sorted by seven pressure layers and six optical depth bins. Historically, cloud-type fluxes have been computed using radiative transfer models based on observed cloud properties. Instead of relying on radiative transfer models, the FBCT product utilizes Moderate Resolution Imaging Spectroradiometer (MODIS) radiances partitioned by cloud type within a CERES footprint to estimate the cloud-type broadband fluxes. The MODIS multichannel derived broadband fluxes were compared with the CERES observed footprint fluxes and were found to be within 1% and 2.5% for LW and SW, respectively, as well as being mostly free of cloud property dependencies. These biases are mitigated by constraining the cloud-type fluxes within each footprint with the CERES Single Scanner Footprint (SSF) observed flux. The FBCT all-sky and clear-sky monthly averaged fluxes were found to be consistent with the CERES SSF1deg product. Several examples of FBCT data are presented to highlight its utility for scientific applications.
Sun, Yuanheng; Knyazikhin, Yuri; She, Xiaojun; Ni, Xiangnan; Chen, Chi; Ren, Huazhong; Myneni, Ranga B.Sun, Y., Y. Knyazikhin, X. She, X. Ni, C. Chen, H. Ren, R. B. Myneni, 2022: Seasonal and long-term variations in leaf area of Congolese rainforest. Remote Sensing of Environment, 268, 112762. doi: 10.1016/j.rse.2021.112762. It is important to understand temporal and spatial variations in the structure and photosynthetic capacity of tropical rainforests in a world of changing climate, increased disturbances and human appropriation. The equatorial rainforests of Central Africa are the second largest and least disturbed of the biodiversly-rich and highly productive rainforests on Earth. Currently, there is a dearth of knowledge about the phenological behavior and long-term changes that these forests are experiencing. Thus, this study reports on leaf area seasonality and its time trend over the past two decades as assessed from multiple remotely sensed datasets. Seasonal variations of leaf area in Congolese forests derived from MODIS data co-vary with the bimodal precipitation pattern in this region, with higher values during the wet season. Independent observational evidence derived from MISR and EPIC sensors in the form of angular reflectance signatures further corroborate this seasonal behavior of leaf area. The bimodal patterns vary latitudinally within this large region. Two sub-seasonal cycles, each consisting of a dry and wet season, could be discerned clearly. These exhibit different sensitivities to changes in precipitation. Contrary to a previous published report, no widespread decline in leaf area was detected across the entire extent of the Congolese rainforests over the past two decades with the latest MODIS Collection 6 dataset. Long-term precipitation decline did occur in some localized areas, but these had minimal impacts on leaf area, as inferred from MODIS and MISR multi-angle observations. Remote sensing; MODIS; Phenology; MISR; Congolese rainforests; DSCOVR EPIC; Leaf area; Long-term trends
Tan, Ivy; Barahona, DonifanTan, I., D. Barahona, 2022: The Impacts of Immersion Ice Nucleation Parameterizations on Arctic Mixed-Phase Stratiform Cloud Properties and the Arctic Radiation Budget in GEOS-5. J. Climate, 35(13), 4049-4070. doi: 10.1175/JCLI-D-21-0368.1. Abstract The influence of four different immersion freezing parameterizations on Arctic clouds and the top-of-the atmosphere (TOA) and surface radiation fluxes is investigated in the fifth version of the National Aeronautics and Space Administration (NASA) Goddard Earth Observing System (GEOS-5) with sea surface temperature, sea ice fraction, and aerosol emissions held fixed. The different parameterizations were derived from a variety of sources, including classical nucleation theory and field and laboratory measurements. Despite the large spread in the ice-nucleating particle (INP) concentrations in the parameterizations, the cloud properties and radiative fluxes had a tendency to form two groups, with the lower INP concentration category producing larger water path and low-level cloud fraction during winter and early spring, whereas the opposite occurred during the summer season. The stability of the lower troposphere was found to strongly correlate with low-cloud fraction and, along with the effect of ice nucleation, ice sedimentation, and melting rates, appears to explain the spring-to-summer reversal pattern in the relative magnitude of the cloud properties between the two categories of simulations. The strong modulation effect of the liquid phase on immersion freezing led to the successful simulation of the characteristic Arctic cloud structure, with a layer rich in supercooled water near cloud top and ice and snow at lower levels. Comparison with satellite retrievals and in situ data suggest that simulations with low INP concentrations more realistically represent Arctic clouds and radiation.
Taylor, Patrick Charles; Itterly, Kyle Frederick; Corbett, Joe; Bucholtz, Anthony; Sejas, Sergio; Su, Wenying; Doelling, David R.; Kato, SeijiTaylor, P. C., K. F. Itterly, J. Corbett, A. Bucholtz, S. Sejas, W. Su, D. R. Doelling, S. Kato, 2022: A Comparison of Top-of-Atmosphere Radiative Fluxes from CERES and ARISE. doi: 10.1002/essoar.10512242.1. Uncertainty in Arctic top-of-atmosphere (TOA) radiative flux observations stems from the low sun angles and the heterogeneous scenes. Advancing our understanding of the Arctic climate system requires
Tezaur, Irina; Peterson, Kara; Powell, Amy; Jakeman, John; Roesler, ErikaTezaur, I., K. Peterson, A. Powell, J. Jakeman, E. Roesler, 2022: Global Sensitivity Analysis Using the Ultra-Low Resolution Energy Exascale Earth System Model. Journal of Advances in Modeling Earth Systems, 14(8), e2021MS002831. doi: 10.1029/2021MS002831. For decades, Arctic temperatures have increased twice as fast as average global temperatures. As a first step toward quantifying parametric uncertainty in Arctic climate, we performed a variance-based global sensitivity analysis (GSA) using a fully coupled, ultra-low resolution (ULR) configuration of version 1 of the U.S. Department of Energy's Energy Exascale Earth System Model (E3SMv1). Specifically, we quantified the sensitivity of six quantities of interests (QOIs), which characterize changes in Arctic climate over a 75 year period, to uncertainties in nine model parameters spanning the sea ice, atmosphere, and ocean components of E3SMv1. Sensitivity indices for each QOI were computed with a Gaussian process emulator using 139 random realizations of the random parameters and fixed preindustrial forcing. Uncertainties in the atmospheric parameters in the Cloud Layers Unified by Binormals (CLUBB) scheme were found to have the most impact on sea ice status and the larger Arctic climate. Our results demonstrate the importance of conducting sensitivity analyses with fully coupled climate models. The ULR configuration makes such studies computationally feasible today due to its low computational cost. When advances in computational power and modeling algorithms enable the tractable use of higher-resolution models, our results will provide a baseline that can quantify the impact of model resolution on the accuracy of sensitivity indices. Moreover, the confidence intervals provided by our study, which we used to quantify the impact of the number of model evaluations on the accuracy of sensitivity estimates, have the potential to inform the computational resources needed for future sensitivity studies. Arctic climate state; Energy Exascale Earth System Model (E3SM); fully coupled; global sensitivity analysis (GSA); ultra-low resolution (ULR); uncertainty quantification (UQ)
Thompson, Chelsea R.; Wofsy, Steven C.; Prather, Michael J.; Newman, Paul A.; Hanisco, Thomas F.; Ryerson, Thomas B.; Fahey, David W.; Apel, Eric C.; Brock, Charles A.; Brune, William H.; Froyd, Karl; Katich, Joseph M.; Nicely, Julie M.; Peischl, Jeff; Ray, Eric; Veres, Patrick R.; Wang, Siyuan; Allen, Hannah M.; Asher, Elizabeth; Bian, Huisheng; Blake, Donald; Bourgeois, Ilann; Budney, John; Bui, T. Paul; Butler, Amy; Campuzano-Jost, Pedro; Chang, Cecilia; Chin, Mian; Commane, Róisín; Correa, Gus; Crounse, John D.; Daube, Bruce; Dibb, Jack E.; DiGangi, Joshua P.; Diskin, Glenn S.; Dollner, Maximilian; Elkins, James W.; Fiore, Arlene M.; Flynn, Clare M.; Guo, Hao; Hall, Samuel R.; Hannun, Reem A.; Hills, Alan; Hintsa, Eric J.; Hodzic, Alma; Hornbrook, Rebecca S.; Huey, L. Greg; Jimenez, Jose L.; Keeling, Ralph F.; Kim, Michelle J.; Kupc, Agnieszka; Lacey, Forrest; Lait, Leslie R.; Lamarque, Jean-Francois; Liu, Junhua; McKain, Kathryn; Meinardi, Simone; Miller, David O.; Montzka, Stephen A.; Moore, Fred L.; Morgan, Eric J.; Murphy, Daniel M.; Murray, Lee T.; Nault, Benjamin A.; Neuman, J. Andrew; Nguyen, Louis; Gonzalez, Yenny; Rollins, Andrew; Rosenlof, Karen; Sargent, Maryann; Schill, Gregory; Schwarz, Joshua P.; Clair, Jason M. St; Steenrod, Stephen D.; Stephens, Britton B.; Strahan, Susan E.; Strode, Sarah A.; Sweeney, Colm; Thames, Alexander B.; Ullmann, Kirk; Wagner, Nicholas; Weber, Rodney; Weinzierl, Bernadett; Wennberg, Paul O.; Williamson, Christina J.; Wolfe, GlenThompson, C. R., S. C. Wofsy, M. J. Prather, P. A. Newman, T. F. Hanisco, T. B. Ryerson, D. W. Fahey, E. C. Apel, C. A. Brock, W. H. Brune, K. Froyd, J. M. Katich, J. M. Nicely, J. Peischl, E. Ray, P. R. Veres, S. Wang, H. M. Allen, E. Asher, H. Bian, D. Blake, I. Bourgeois, J. Budney, T. P. Bui, A. Butler, P. Campuzano-Jost, C. Chang, M. Chin, R. Commane, G. Correa, J. D. Crounse, B. Daube, J. E. Dibb, J. P. DiGangi, G. S. Diskin, M. Dollner, J. W. Elkins, A. M. Fiore, C. M. Flynn, H. Guo, S. R. Hall, R. A. Hannun, A. Hills, E. J. Hintsa, A. Hodzic, R. S. Hornbrook, L. G. Huey, J. L. Jimenez, R. F. Keeling, M. J. Kim, A. Kupc, F. Lacey, L. R. Lait, J. Lamarque, J. Liu, K. McKain, S. Meinardi, D. O. Miller, S. A. Montzka, F. L. Moore, E. J. Morgan, D. M. Murphy, L. T. Murray, B. A. Nault, J. A. Neuman, L. Nguyen, Y. Gonzalez, A. Rollins, K. Rosenlof, M. Sargent, G. Schill, J. P. Schwarz, J. M. S. Clair, S. D. Steenrod, B. B. Stephens, S. E. Strahan, S. A. Strode, C. Sweeney, A. B. Thames, K. Ullmann, N. Wagner, R. Weber, B. Weinzierl, P. O. Wennberg, C. J. Williamson, G. Wolfe, 2022: The NASA Atmospheric Tomography (ATom) Mission: Imaging the Chemistry of the Global Atmosphere. Bull. Amer. Meteor. Soc., 103(3), E761-E790. doi: 10.1175/BAMS-D-20-0315.1. Abstract This article provides an overview of the NASA Atmospheric Tomography (ATom) mission and a summary of selected scientific findings to date. ATom was an airborne measurements and modeling campaign aimed at characterizing the composition and chemistry of the troposphere over the most remote regions of the Pacific, Southern, Atlantic, and Arctic Oceans, and examining the impact of anthropogenic and natural emissions on a global scale. These remote regions dominate global chemical reactivity and are exceptionally important for global air quality and climate. ATom data provide the in situ measurements needed to understand the range of chemical species and their reactions, and to test satellite remote sensing observations and global models over large regions of the remote atmosphere. Lack of data in these regions, particularly over the oceans, has limited our understanding of how atmospheric composition is changing in response to shifting anthropogenic emissions and physical climate change. ATom was designed as a global-scale tomographic sampling mission with extensive geographic and seasonal coverage, tropospheric vertical profiling, and detailed speciation of reactive compounds and pollution tracers. ATom flew the NASA DC-8 research aircraft over four seasons to collect a comprehensive suite of measurements of gases, aerosols, and radical species from the remote troposphere and lower stratosphere on four global circuits from 2016 to 2018. Flights maintained near-continuous vertical profiling of 0.15–13-km altitudes on long meridional transects of the Pacific and Atlantic Ocean basins. Analysis and modeling of ATom data have led to the significant early findings highlighted here.
Tian, Lei; Zhang, Baoqing; Wang, Xuejin; Chen, Shuoyu; Pan, BaotianTian, L., B. Zhang, X. Wang, S. Chen, B. Pan, 2022: Large-Scale Afforestation Over the Loess Plateau in China Contributes to the Local Warming Trend. Journal of Geophysical Research: Atmospheres, 127(1), e2021JD035730. doi: 10.1029/2021JD035730. Afforestation is a major anthropogenic forcing to the global and regional climate. However, the biophysical impacts of large-scale afforestation on local temperature in temperate regions remain unclear, due to the closely matched but compensating radiative and non-radiative effects. The Grain for Green Program (GFGP) is a large-scale afforestation program implemented over the Loess Plateau (LP) in China. The GFGP thus provides an ideal platform to explore the temperature effect of afforestation. This study investigated such a temperature effect through long-term, high-resolution simulations incorporating satellite observations in a coupled land-atmosphere model. With an optimal combination of physical schemes proposed by this study, we greatly improved the accuracy of regional climate modeling. The results reveal that the afforestation caused a significant decline (−0.50% yr−1) in albedo. An increment in net shortwave radiation mainly led to an increment in net radiation (7.95 W m−2). The afforestation also led to an increment in sensible heat flux (3.78 W m−2). Consequently, the afforestation caused a warming effect (0.36°C) in 2-meter air temperature at the inter-annual scale. At the intra-annual scale, there was a cooling effect in July and August, while other months demonstrated a warming effect. The radiative effect dominated local temperature change induced by the afforestation over the LP. Therefore, the large-scale afforestation contributed to the local warming trend. Our findings highlight the temperature effect of afforestation, and imply that more attention should be paid to future revegetation to carefully assess its potential influence on regional climate. temperature; regional climate; evapotranspiration; afforestation; energy and water cycle; land-atmosphere model
Truong, Son C. H.; Huang, Yi; Siems, Steven T.; Manton, Michael J.; Lang, FranciscoTruong, S. C. H., Y. Huang, S. T. Siems, M. J. Manton, F. Lang, 2022: Biases in the thermodynamic structure over the Southern Ocean in ERA5 and their radiative implications. International Journal of Climatology, n/a(n/a). doi: 10.1002/joc.7672. The thermodynamic structure of the lower troposphere in the 37 standard levels ERA5 reanalysis has been evaluated against 2,186 high-resolution upper air soundings collected over the Southern Ocean (SO). The reanalysis, which incorporated these soundings, was found to be skilled in depicting the general synoptic meteorology and thermodynamic structure as defined by the cluster analysis of Truong et al. (2020) Journal of Geophysical Research: Atmospheres, 125, e2020JD033214. Using dew-point depression as a proxy for cloud, however, we found a significant reduction in the number of inferred cloud layers, which is inherited from a bias in the specific humidity in the ERA5 reanalysis, most notably over the high latitudes of the SO, where a multilayer cloud structure is frequently observed. The reanalysis was also found to have thinner inferred cloud geometric layer and shallower cloud top heights. Further analysis showed that the reanalysis displays a greater percentage of soundings having no inversion with this bias being more pronounced at high latitudes that tends to be associated with the colder sea surface temperature. While the statistics of the main inversion height are largely consistent, the average inversion strength in the ERA5 reanalysis is found to be weaker than the observations. We anticipate the 137-level ERA5 reanalysis simulation yields a smoothed vertical structure, from which the 37 standard levels ERA5 reanalysis is linearly interpolated. An examination of the sensitivity of the radiative transfer to cloud macrophysics suggests that the correct representation of thin multiple cloud layers can help reduce the amount of downward shortwave surface radiation over the SO. Southern Ocean; marine atmospheric boundary layer; inversion; multilayer clouds; radiation bias
Turbeville, S. M.; Nugent, J. M.; Ackerman, T. P.; Bretherton, C. S.; Blossey, P. N.Turbeville, S. M., J. M. Nugent, T. P. Ackerman, C. S. Bretherton, P. N. Blossey, 2022: Tropical Cirrus in Global Storm-Resolving Models: 2. Cirrus Life Cycle and Top-of-Atmosphere Radiative Fluxes. Earth and Space Science, 9(2), e2021EA001978. doi: 10.1029/2021EA001978. Cirrus clouds of various thicknesses and radiative characteristics extend over much of the tropics, especially around deep convection. They are difficult to observe due to their high altitude and sometimes small optical depths. They are also difficult to simulate in conventional global climate models, which have coarse grid spacings and simplified parameterizations of deep convection and cirrus formation. We investigate the representation of tropical cirrus in global storm-resolving models (GSRMs), which have higher spatial resolution and explicit convection and could more accurately represent cirrus cloud processes. This study uses GSRMs from the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) project. The aggregate life cycle of tropical cirrus is analyzed using joint albedo and outgoing longwave radiation (OLR) histograms to assess the fidelity of models in capturing the observed cirrus cloud populations over representative tropical ocean and land regions. The proportions of optically thick deep convection, anvils, and cirrus vary across models and are portrayed in the vertical distribution of cloud cover and top-of-atmosphere radiative fluxes. Model differences in cirrus populations, likely driven by subgrid processes such as ice microphysics, dominate over regional differences between convectively active tropical land and ocean locations. cirrus; life cycle; tropical tropopause layer; model comparison; DYAMOND; global storm-resolving models
Volvach, Alexandr; Kurbasova, Galina; Volvach, LarisaVolvach, A., G. Kurbasova, L. Volvach, 2022: Time series analysis of temperatures and insolation of the Earth's surface at Kara-Dag using satellite observation. Advances in Space Research, 69(12), 4228-4239. doi: 10.1016/j.asr.2022.04.016. This article discusses the results of a numerical analysis of the time series of the surface temperature, air temperature at a height of 2 m, as well as the total insolation falling to the earth at the Kara-Dag point over the past 38 years. Statistical analysis of observations and continuous time-frequency wavelet analysis are performed. Models of seasonal fluctuations in three time series of observations are compared. Coherent fluctuations were established between variations in total insolation data and data variations: of length of the day (LOD) (the period of variations is 11.8 years, the square of the coherence modulus is 0.85); of solar activity (the period of variations is 10.5 years, the squared modulus of coherence is 0.8; and the period of variations is 3.6 years, the squared modulus of coherence is 0.85); of global temperature indices (the period of variations is 2.3 years, the squared modulus of coherence is 0.7; and the period of variations is 3.5 years, the squared modulus of coherence is 0.9), respectively. The time evolution of observations in order to detect signs of chaotic oscillations is discussed. Earth; Insolation; Chaotic oscillations; Global temperature; POWER
Wall, Casey J.; Lutsko, Nicholas J.; Vishny, David N.Wall, C. J., N. J. Lutsko, D. N. Vishny, 2022: Revisiting Cloud Radiative Heating and the Southern Annular Mode. Geophysical Research Letters, n/a(n/a), e2022GL100463. doi: 10.1029/2022GL100463. Cloud-circulation interactions have a potentially large but uncertain influence on regional climate. Here we use satellite observations to investigate relationships between atmospheric cloud radiative heating and hemispheric-scale shifts in the Southern Hemisphere extratropical jet stream, as represented by the Southern Annular Mode. In contrast to a previous study, we find that poleward jet shifts cause bottom-heavy heating anomalies. The heating anomalies arise from two distinct mechanisms: First, poleward jet shifts promote anomalous large-scale subsidence equatorward of the mean jet latitude. This increases the fraction of low clouds that are exposed to space, thereby enhancing lower-tropospheric radiative cooling. Second, deep and multi-layer clouds in extratropical cyclones shift poleward with the jet, causing radiative heating anomalies throughout the troposphere. The bottom-heavy structure of the heating anomalies occurs because low clouds strongly emit radiation. These results establish new observational benchmarks for understanding extratropical cloud-circulation interactions. Annular Modes; Cloud Radiative Effects; Cloud-Circulation Interactions
Wall, Casey J.; Storelvmo, Trude; Norris, Joel R.; Tan, IvyWall, C. J., T. Storelvmo, J. R. Norris, I. Tan, 2022: Observational Constraints on Southern Ocean Cloud-Phase Feedback. J. Climate, 35(15), 5087-5102. doi: 10.1175/JCLI-D-21-0812.1. Abstract Shortwave radiative feedbacks from Southern Ocean clouds are a major source of uncertainty in climate projections. Much of this uncertainty arises from changes in cloud scattering properties and lifetimes that are caused by changes in cloud thermodynamic phase. Here we use satellite observations to infer the scattering component of the cloud-phase feedback mechanism and determine its relative importance by comparing it with an estimate of the overall temperature-driven cloud feedback. The overall feedback is dominated by an optical thinning of low-level clouds. In contrast, the scattering component of cloud-phase feedback is an order of magnitude smaller and is primarily confined to free-tropospheric clouds. The small magnitude of this feedback component is a consequence of counteracting changes in albedo from cloud optical thickening and enhanced forward scattering by cloud particles. These results indicate that shortwave cloud feedback is likely positive over the Southern Ocean and that changes in cloud scattering properties arising from phase changes make a small contribution to the overall feedback. The feedback constraints shift the projected 66% confidence range for the global equilibrium temperature response to doubling atmospheric CO2 by about +0.1 K relative to a recent consensus estimate of cloud feedback. Significance Statement Understanding how clouds respond to global warming is a key challenge of climate science. One particularly uncertain aspect of the cloud response involves a conversion of ice particles to liquid droplets in extratropical clouds. Here we use satellite data to infer how cloud-phase conversions affect climate by changing cloud albedo. We find that ice-to-liquid conversions increase cloud optical thickness and shift the scattering angles of cloud particles toward the forward direction. These changes in optical properties have offsetting effects on cloud albedo. This finding provides new insight about how changes in cloud phase affect climate change.
Wang, Fei; Zhang, Hua; Wang, Qiuyan; Xie, Bing; Zhou, Xixun; Liu, QingquanWang, F., H. Zhang, Q. Wang, B. Xie, X. Zhou, Q. Liu, 2022: An Assessment of Short-term Global and East Asian Local Climate Feedbacks using New Radiative Kernels. Climate Dynamics. doi: 10.1007/s00382-022-06369-z. This study estimates short-term climate feedbacks by using a new set of radiative kernels applied to observations and the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations. The new kernels are generated based on multiyear satellite observations, and they can well reproduce the top-of-atmosphere (TOA) radiation budget. The choice of radiative kernels influences the feedback estimation, especially the surface albedo feedback and cloud feedback in the Arctic and the Southern Ocean. Observational estimates show that tropospheric water vapor feedback makes the largest contribution to global warming, while lapse rate feedback is the largest contributor to local warming over East Asia. Compared to the observations, biases occur but differ when simulating global and East Asian local climate feedbacks. CMIP6 models overestimate global mean Planck, lapse rate, stratospheric temperature and water vapor, and cloud feedbacks, but underestimate global mean tropospheric water vapor and surface albedo feedbacks. Over East Asia, local Planck and lapse rate feedbacks are underestimated, while tropospheric water vapor, stratospheric temperature, and cloud feedbacks are overestimated. The simulation biases in local longwave (LW) and shortwave (SW) cloud feedbacks over East Asia are considerable, probably due to the failure in simulating cloud fraction response of marine cirrostratus, deep convective cloud, and stratus. The intermodel spread of cloud feedback is the largest for both global and East Asian local feedback processes. Our results suggest that contemporary climate models are still difficult to accurately simulate global and local climate feedback processes. East Asia; CMIP6 models; Observations; Radiative kernels; Short-term climate feedback
Wang, Hao; Wang, Minghuai; Zhang, Zhibo; Larson, Vincent E.; Griffin, Brian M.; Guo, Zhun; Zhu, Yannian; Rosenfeld, Daniel; Cao, Yang; Bai, HemingWang, H., M. Wang, Z. Zhang, V. E. Larson, B. M. Griffin, Z. Guo, Y. Zhu, D. Rosenfeld, Y. Cao, H. Bai, 2022: Improving the treatment of subgrid cloud variability in warm rain simulation in CESM2. Journal of Advances in Modeling Earth Systems, n/a(n/a), e2022MS003103. doi: 10.1029/2022MS003103. Representing subgrid variability of cloud properties has always been a challenge in global climate models (GCMs). In many cloud microphysics schemes, the warm rain non-linear process rates calculated based on grid-mean cloud properties are usually scaled by an enhancement factor (EF) to account for the effects of subgrid cloud variability. In our study, we find that the EF derived from Cloud Layers Unified by Binormals (CLUBB) in Community Atmosphere Model version 6 (CAM6) is severely overestimated in most of the cloudy oceanic areas, which leads to strong overestimation of the autoconversion rate. We improve the EF in warm rain simulation by developing a new formula for in-cloud subgrid cloud water variance. With the updated subgrid cloud water variance and EF treatment, the liquid cloud fraction (LCF) and cloud optical thickness (COT) increases noticeably for marine stratocumulus, and the shortwave cloud forcing (SWCF) matches better with observations. The updated formula improves the relationship between autoconversion rate and cloud droplet number concentration (CDNC), and it decreases the sensitivity of autoconversion rate to aerosols. The sensitivity of liquid water path (LWP) to aerosols decreases noticeably and is in better agreement with that in MODIS. Although the sensitivity of COT is similar to that in MODIS, CAM6 underestimates the sensitivity of grid-mean SWCF to aerosols because of the underestimation in the sensitivities of LCF and in-cloud SWCF. Our results indicate the importance of representing reasonable subgrid cloud variability in the simulation of cloud properties and aerosol-cloud interaction in GCMs. aerosol-cloud interaction; CLUBB; marine boundary layer clouds; CAM6; subgrid variability
Wang, Shiyao; Wang, Tianxing; Leng, Wanchun; Wang, Gaofeng; Letu, HusiWang, S., T. Wang, W. Leng, G. Wang, H. Letu, 2022: Toward an Improved Global Longwave Downward Radiation Product by Fusing Satellite and Reanalysis Data. IEEE Transactions on Geoscience and Remote Sensing, 60, 1-16. doi: 10.1109/TGRS.2022.3179017. Surface longwave downward radiation (LWDR) plays an important role in modulating greenhouse effect and climate change. Constructing a global longtime series LWDR dataset is greatly necessary to systematically and in-depth study the LWDR effect on the climate. However, the current multisource LWDR products (satellite and reanalysis) show large differences in terms of both spatiotemporal resolutions and accuracy in various regions. Therefore, it is necessary to fuse multisource datasets to generate more accurate LWDR with high spatiotemporal resolution on a global scale. To this end, a downscaling strategy is first proposed to generate LWDR dataset with 0.25° resolution from CERES-SYN data with 1° scale, by incorporating the land surface temperature (LST), total column water vapor (TCWV), and elevation. Then, a machine learning-based fusion method is provided to generate a global hourly LWDR dataset with a spatial resolution of 0.25° by combining three products (CERES-SYN, ERA5, and GLDAS). Compared with ground measurements, the performance of generated LWDR product reveals that the correlation coefficient ( $R$ ), mean bias error (BIAS), and root-mean-square error (RMSE) were 0.97, −0.95 W/m2, and 22.38 W/m2 over the land and 0.99, −0.88 W/m2, and 10.96 W/m2 over the ocean, respectively. In particular, it shows improved accuracy in the low and middle latitude regions compared with other LWDR products. Considering its better accuracy and higher spatiotemporal resolution, the new LWDR product can provide essential data for deeply understanding the global energy balance and even the global warming. Moreover, the proposed fusion strategy can be enlightening for readers in the fields of multisource data combination and big data analysis. Remote sensing; data fusion; Ocean temperature; Spatial resolution; Land surface temperature; GLDAS; Data models; machine learning; ERA5; CERES-SYN; Machine learning; Fuses; surface longwave downward radiation (LWDR)
Wang, Yipu; Li, Rui; Hu, Jiheng; Fu, Yuyun; Duan, Jiawei; Cheng, Yuanxi; Song, BinbinWang, Y., R. Li, J. Hu, Y. Fu, J. Duan, Y. Cheng, B. Song, 2022: Evaluation of evapotranspiration estimation under cloud impacts over China using ground observations and multiple satellite optical and microwave measurements. Agricultural and Forest Meteorology, 314, 108806. doi: 10.1016/j.agrformet.2021.108806. Evapotranspiration (ET) is an important component of the hydrological cycle and energy balance in a land-atmosphere system. Satellite remote sensing has been widely used to estimate regional and global ET, but most previous methods depend on optical measurements that are limited to cloud-free conditions. This makes ET estimation challenging under cloudy sky. Currently, evaluations of satellite ET estimation under various cloud conditions remain lacking at the regional scale. Owing to the ability to penetrate clouds, satellite passive microwave measurements are powerful tools for retrieving ET under clouds. This study evaluated a satellite microwave-based daily ET method under all sky conditions over the part of China between 18°N and 50°N from 2003 to 2010, using microwave emissivity difference vegetation index (EDVI) as the proxy of vegetation water content (VWC). Validations using the surface water balance method found that the estimated ET (EDVI-ET) had an overall small bias (6.18%) in eight river basins. EDVI-ET displayed consistent spatiotemporal patterns with global MOD16 ET, with high spatial correlation (R>0.71) and monthly temporal correlation (R>0.82) throughout four seasons. Their differences were also small ( cloudy sky; Evapotranspiration (ET); microwave Emissivity Difference Vegetation Index (EDVI); MOD16
Wang, Zhenquan; Ge, Jinming; Yan, Jialin; Li, Wenxue; Yang, Xuan; Wang, Meihua; Hu, XiaoyuWang, Z., J. Ge, J. Yan, W. Li, X. Yang, M. Wang, X. Hu, 2022: Interannual shift of tropical high cloud diurnal cycle under global warming. Climate Dynamics. doi: 10.1007/s00382-022-06273-6. This research focuses on the observed tropical oceanic high clouds above the 300 hPa level, to investigate their diurnal cycles and radiative effects at the top of atmosphere. The diurnal centroid is used to quantify the diurnal cycle based on circular statistics to indicate the daily peaking time of cloud cover. It is found that the diurnal cycle of the tropical oceanic high clouds can significantly impact their cloud radiative effects, with a correlation coefficient of − 0.63 at the 95% significant level and a slope of − 14.5 Wm−2 h−1 between the net cloud radiative effects and the diurnal centroid shifting from midnight towards noon. This implies that the changes of the diurnal cycle can strongly influence the Earth radiative budget, and thus possibly impose radiative feedbacks to affect atmospheric circulations under global climate warming. It is also found that the strength of convection and the cold point temperature are two major environmental factors in influencing the diurnal-cycle centroid of the tropical oceanic high clouds. Furthermore, according to observations, the correlation coefficient between the diurnal-cycle centroid of the tropical oceanic high clouds and the global mean temperature is 0.75 at the 95% significant level, indicating a 2-h shift of the tropical oceanic high clouds towards noon with 1℃ increases of the global mean temperature.
Wang, Zhili; Wang, Chense; Yang, Su; Lei, Yadong; Che, Huizheng; Zhang, Xiaoye; Wang, QiuyanWang, Z., C. Wang, S. Yang, Y. Lei, H. Che, X. Zhang, Q. Wang, 2022: Evaluation of surface solar radiation trends over China since the 1960s in the CMIP6 models and potential impact of aerosol emissions. Atmospheric Research, 268, 105991. doi: 10.1016/j.atmosres.2021.105991. Accurate representation of surface solar radiation (SSR) trends is an important indicator for global climate models (GCMs) to correctly reproducing the historical climate evolution. This study examines the annual mean SSR trends in China under all-sky and clear-sky conditions for the period 1961–2014 in 34 Coupled Model Intercomparison Project Phase 6 (CMIP6) models using the latest homogenized in-situ SSR dataset. The site-observed annual mean SSR over China shows a significant decadal decline during 1961–2005 but an uptrend during 2006–2014, with the trends being −6.4 (−8.6) W m−2 and + 2.5 (+5.9) W m−2 per decade under all-sky (clear-sky) condition, respectively. All CMIP6 models simulate the sustained decline in SSR over China for the period 1961–2005 but significantly underestimate the dimming. The model results show trends of −1.9 ± 0.5 W m−2 and -2.5 ± 0.7 W m−2 per decade during 1961–2005 under all-sky and clear-sky conditions, respectively, which are around one third of the observed results. Furthermore, the models fail to capture the reversal of SSR trends in China during 2006–2014, with the trends being −1.1 ± 1.7 W m−2 and -2.2 ± 0.9 W m−2 per decade under all-sky and clear-sky conditions, respectively. We infer that the underestimation of anthropogenic aerosol emissions, especially absorbing black carbon emissions cause the underestimated simulation of SSR in dimming period over China. After 2005, the unseasonal increase in carbonaceous aerosol emissions and the weaker decline of sulfur dioxide emissions in China in the models result in an opposite SSR trends relative to the trends based on the site-observations. Our results suggest that improving the anthropogenic aerosol emissions inventory will be useful for generating a more accurate reproduction of the regional SSR evolution over China in GCMs. Surface solar radiation; CMIP6; Aerosol emissions; Black carbon
Wei, Linyi; Lu, Zheng; Wang, Yong; Liu, Xiaohong; Wang, Weiyi; Wu, Chenglai; Zhao, Xi; Rahimi, Stefan; Xia, Wenwen; Jiang, YiquanWei, L., Z. Lu, Y. Wang, X. Liu, W. Wang, C. Wu, X. Zhao, S. Rahimi, W. Xia, Y. Jiang, 2022: Black carbon-climate interactions regulate dust burdens over India revealed during COVID-19. Nature Communications, 13(1), 1839. doi: 10.1038/s41467-022-29468-1. India as a hotspot for air pollution has heavy black carbon (BC) and dust (DU) loadings. BC has been identified to significantly impact the Indian climate. However, whether BC-climate interactions regulate Indian DU during the premonsoon season is unclear. Here, using long-term Reanalysis data, we show that Indian DU is positively correlated to northern Indian BC while negatively correlated to southern Indian BC. We further identify the mechanism of BC-dust-climate interactions revealed during COVID-19. BC reduction in northern India due to lockdown decreases solar heating in the atmosphere and increases surface albedo of the Tibetan Plateau (TP), inducing a descending atmospheric motion. Colder air from the TP together with warmer southern Indian air heated by biomass burning BC results in easterly wind anomalies, which reduces dust transport from the Middle East and Sahara and local dust emissions. The premonsoon aerosol-climate interactions delay the outbreak of the subsequent Indian summer monsoon. Climate change; Atmospheric science
Wu, Wen-Ying; Yang, Zong-LiangWu, W., Z. Yang, 2022: Aridity-Dependent Land Surface Skin Temperature Biases in CMIP5/6. Geophysical Research Letters, 49(15), e2022GL098952. doi: 10.1029/2022GL098952. Land surface skin temperature, a critical indicator of climate change, connects the water and energy cycles between the land and the atmosphere. Here, we evaluate the simulations of land surface skin temperature from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and CMIP6 models with satellite-based datasets and reanalysis. We find systematic cold skin temperature biases over arid regions in CMIP5/CMIP6 simulations. Over arid and semi-arid regions, latent heat biases drive skin temperature biases by evaporative cooling. Over humid regions, surface downward shortwave and albedo biases are relatively more critical. Spatial patterns of biases remain similar in the latest CMIP6 simulations, suggesting systematic biases in land-atmosphere interactions. These biases need to be corrected or considered while using models for future projections. CMIP; land surface temperature; land-atmosphere interaction
Xie, Xiaoming; He, Bin; Guo, Lanlan; Huang, Ling; Hao, Xingming; Zhang, Yafeng; Liu, Xuebang; Tang, Rui; Wang, SifanXie, X., B. He, L. Guo, L. Huang, X. Hao, Y. Zhang, X. Liu, R. Tang, S. Wang, 2022: Revisiting dry season vegetation dynamics in the Amazon rainforest using different satellite vegetation datasets. Agricultural and Forest Meteorology, 312, 108704. doi: 10.1016/j.agrformet.2021.108704. There has been a debate regarding whether the Amazon rainforest is greening during the dry season. This is partially because of the great uncertainty associated with the ability of different vegetation indices to accurately assess tropical vegetation status. This paper, revisit this issue by comprehensively examining the seasonal variations in vegetation recorded in various satellite-based vegetation datasets, namely, the leaf area index (LAI), contiguous solar-induced fluorescence (CSIF), enhanced vegetation index (EVI), and vegetation optical depth (VOD). All four of these vegetation datasets show an increase in vegetation during the dry season in most parts of the Amazon; however, the vegetation changes are not only spatially variable, but also differ among the datasets. This may be attributable in part to the different physical characteristics captured by each of the datasets. For example, the seasonal maximum value occurs first in the LAI, followed by the CSIF, EVI, and VOD, in that order. The seasonal cycle of the LAI agrees reasonably well with in-situ observations of leaf flush and leaf fall. As new leaf production offsets senescence and abscission, the dry-season vegetation increases in most parts of the Amazon rainforest. Partial correlation analysis was used to further investigate the potential climatic cues (i.e., precipitation, temperature and radiation) associated with the seasonal changes recorded in the vegetation data. We found that precipitation and radiation were the dominant potential cues for seasonal VOD (48%) and LAI (59%) changes, respectively. However, CSIF appears to be associated more closely with temperature and precipitation, with significant correlations observed across ∼x223C 37% of the Amazon rainforest area for both with CSIF. Finally, variations in the EVI showed similar sensitivity to all three climatic variables considered. The findings presented here will greatly improve our understanding of vegetation dynamics and the carbon cycle in the Amazon rainforest ecosystem. Amazon; Dry season; Greening; Rainforest; Vegetation data
Xu, Jiawen; Zhang, Xiaotong; Zhang, Weiyu; Hou, Ning; Feng, Chunjie; Yang, Shuyue; Jia, Kun; Yao, Yunjun; Xie, Xianhong; Jiang, Bo; Cheng, Jie; Zhao, Xiang; Liang, ShunlinXu, J., X. Zhang, W. Zhang, N. Hou, C. Feng, S. Yang, K. Jia, Y. Yao, X. Xie, B. Jiang, J. Cheng, X. Zhao, S. Liang, 2022: Assessment of surface downward longwave radiation in CMIP6 with comparison to observations and CMIP5. Atmospheric Research, 270, 106056. doi: 10.1016/j.atmosres.2022.106056. Surface downward longwave radiation (SDLR) plays an important role in understanding the greenhouse effect and global warming. The simulated SDLR from 47 coupled models in the Coupled Model Intercomparison Project (CMIP6) general circulation models (GCMs) was evaluated by comparing them with ground measurements and CMIP5 results. The estimated SDLR using all CMIP6 GCMs based on the multimodel ensemble (MME) methods was validated as well. The bias values of the SDLR simulations from individual CMIP6 GCMs averaged over the selected 183 sites around the world varied from −10 to 10 W m−2, while the root mean squared error (RMSE) values ranged from 20 to 26 W m−2. Compared to CMIP5 models, the CMIP6 GCMs did not show a significant tendency to underestimate SDLR. However, the SDLR from CMIP6 GCMs exhibited the relatively better precision at low altitude and low latitude sites compared to that at high altitude and high latitude sites. Moreover, the Bayesian model averaging (BMA) method increased the correlation coefficient (R) by approximately 0.02 and reduced the RMSE by approximately 5 W m−2 on average compared to the individual CMIP6 GCMs. The trend in SDLR was also investigated in this study, which has been related to the changes in air temperature (SAT), and water vapor pressure (WVP). CMIP5; GCMs; CMIP6; Bayesian model averaging; Multimodel ensemble; Surface downward longwave radiation (SDLR)
Yadav, Ramashray; Giri, R. K.; Bhan, S. C.Yadav, R., R. K. Giri, S. C. Bhan, 2022: High-resolution outgoing long wave radiation data (2014–2020) of INSAT-3D Imager and its comparison with Clouds and Earth’s Radiant Energy System (CERES) data. Advances in Space Research, 70(4), 976-991. doi: 10.1016/j.asr.2022.05.053. As a proxy of convection INSAT-3D satellite-derived product Outgoing Long Wave Radiation (OLR) data is available in both high temporal and spatial ranges over 40°N–40°S & 35°E–135°E. Daily gridded data set of 7 years of data (2014–2020) has been generated at 10 km × 10 km resolution and the same is compared with Clouds and Earth’s Radiant Energy System (CERES) instrument data taken from CERES as reference. Almost all the INSAT-3D data set generated is Global Space-based Inter-Calibration System (GSICS) corrected. The spatiotemporal consistency of the data set was statistically analyzed and found to be reasonably good agreement having a bias of ∼±5–6 W/m2 over above said domain. This inter-comparison is essential to get confidence in the data sets and release it further in the public domain for any scientific study. Again, this data set will be very useful in diagnosing the variations of convection at different scales (daily, weekly, monthly, annual, seasonal, intra-seasonal, etc.) & an important repository of Daily Climate Data Records (DCDR) for future studies. The specified domain of the present study is affected throughout the year with variable (weak, moderate, intense, or severe) spatiotemporal Inter-Tropical Convergence Zone (ITCZ) convection streams due to different types of weather activities (winter, pre-monsoon, monsoon, and post-monsoon) throughout the year. To visualize the importance of this high-resolution OLR data set a case study of Cyclone Amphan and Vayu is presented. The extremely severe intense convection (OLR departure −112 W/m2 with INSAT-3D new data set whereas −104 W/m2 in CERES data) was observed in both the data sets on 18th May-2020 at 13.7–16°N & 86.2–86.8°E during the super cyclonic stage of Amphan. A similar type of variation in the OLR has been noticed for Vayu Cyclone (OLR departure −94 W/m2 with INSAT-3D new data set whereas −86 W/m2 in CERES data). This information is very useful in impact-based forecasting and further future actions for disaster managers/decision-makers. The localized convective features during cyclone activity over the Indian Ocean region both in the Arabian Sea and the Bay of Bengal are well captured with this new data set and the difference in OLR of INSAT -3D and CERES -9 W/m2 and -12 W/m2 respectively. CERES; ITCZ; OLR; GSICS & DCDR; INSAT-3D; Spatiotemporal
Yang, Jie; Zhao, Chuanfeng; Sun, Yue; Chi, Yulei; Yang, YikunYang, J., C. Zhao, Y. Sun, Y. Chi, Y. Yang, 2022: Aerosol first indirect effect over narrow longitude regions of North Pacific and same-latitude lands. Atmospheric Environment, 277, 119081. doi: 10.1016/j.atmosenv.2022.119081. Aerosol first indirect effect (FIE), which causes variations of cloud droplet effective radius (re) and then cloud radiative effect (CRE), is one of the critical factors leading to uncertainties in climate model simulations. Different from most previous studies over continental regions, using 10-year observation data from CERES, this study investigates the statistical relationships between aerosol optical depth (AOD) and non-precipitating single-layer liquid phase cloud re and surface shortwave CRE (CRESW) over narrow longitude regions of North Pacific and its eastern and western lands at equal latitudes, along with the estimation of aerosol FIE. Both surface CRESW and cloud re are highly affected by aerosols. When AOD is less than 0.3–0.4 and liquid water path (LWP) is greater than 30 g/m2, positive AOD-CRESW and negative AOD-cloud re relationships are found over both ocean and land. With the increase of AOD, the sensitivity of CRESW and cloud re to aerosol is weakened, but both have greater fluctuations. The latitude dependence of the CRESW and cloud re variations with AOD are weak. The increases in liquid water path (LWP) when LWP is in a certain range (30–120 g/m2 over ocean and 30–90 g/m2 over land) can highly increase CRESW and promote the growth of cloud droplets. We also find that FIE values are positive under clean condition, while negative under polluted condition. Associated with the much less aerosol amount and more sufficient water supply, the FIE values over the ocean are distinctly larger than that over the land. Ocean; Liquid water path; Aerosol first indirect effect; Cloud droplet effective radius; Land; Shortwave cloud radiative effect
Yi, BingqiYi, B., 2022: Diverse cloud radiative effects and global surface temperature simulations induced by different ice cloud optical property parameterizations. Scientific Reports, 12(1), 10539. doi: 10.1038/s41598-022-14608-w. The representation of ice cloud optical properties in climate models has long been a difficult problem. Very different ice cloud optical property parameterization schemes developed based on very different assumptions of ice particle shape habits, particle size distributions, and surface roughness conditions, are used in various models. It is not clear as to how simulated climate variables are affected by the ice cloud optical property parameterizations. A total of five ice cloud optical property parameterization schemes, including three based on the ice habit mixtures suitable for general ice clouds, mid-latitude synoptic ice clouds, and tropical deep convective ice clouds, and the other two based on single ice habits (smooth hexagonal column and severely roughened column aggregate), are developed under a same framework and are implemented in the National Center for Atmospheric Research Community Atmospheric Model version 5. A series of atmosphere-only climate simulations are carried out for each of the five cases with different ice parameterizations. The differences in the simulated top of the atmosphere shortwave and longwave cloud radiative effects (CREs) are evaluated, and the global averaged net CRE differences among different cases range from − 1.93 to 1.03 Wm−2. The corresponding changes in simulated surface temperature are found to be most prominent on continental regions which amount to several degrees in Kelvin. Our results indicate the importance of choosing a reasonable ice cloud optical property parameterization in climate simulations. Environmental sciences; Climate sciences
Zeppetello, Lucas R. Vargas; Battisti, David S.; Baker, Marcia B.Zeppetello, L. R. V., D. S. Battisti, M. B. Baker, 2022: The Physics of Heat Waves: What Causes Extremely High Summertime Temperatures?. J. Climate, 35(7), 2231-2251. doi: 10.1175/JCLI-D-21-0236.1. Abstract We analyze observations and develop a hierarchy of models to understand heat waves—long-lived, high temperature anomalies—and extremely high daily temperatures during summertime in the continental extratropics. Throughout the extratropics, the number of extremely hot days found in the three hottest months is much greater than expected from a random, single-process model. Furthermore, in many locations the temperature skewness switches from negative on daily time scales to positive on monthly time scales (or shifts from positive on daily time scales to higher positive values on monthly time scales) in ways that cannot be explained by averaging alone. These observations motivate a hierarchy of models of the surface energy and moisture budgets that we use to illuminate the physics responsible for daily and monthly averaged temperature variability. Shortwave radiation fluctuations drive much of the variance and the negative skewness found in daily temperature observations. On longer time scales, precipitation-induced soil moisture anomalies are important for temperature variability and account for the shift toward positive skewness in monthly averaged temperature. Our results demonstrate that long-lived heat waves are due to (i) the residence time of soil moisture anomalies and (ii) a nonlinear feedback between temperature and evapotranspiration via the impact of temperature on vapor pressure deficit. For most climates, these two processes give rise to infrequent, long-lived heat waves in response to randomly distributed precipitation forcing. Combined with our results concerning high-frequency variability, extremely hot days are seen to be state-independent filigree driven by shortwave variability acting on top of longer-lived, moisture-driven heat waves.
Zhan, Chuan; Liang, ShunlinZhan, C., S. Liang, 2022: Improved estimation of the global top-of-atmosphere albedo from AVHRR data. Remote Sensing of Environment, 269, 112836. doi: 10.1016/j.rse.2021.112836. The top-of-atmosphere (TOA) albedo, a key component of the earth's energy balance, can be monitored regularly by satellite observations. Compared to the previous study Song et al. (2018), this paper estimates TOA albedo by directly linking Advanced Very High Resolution Radiometer (AVHRR) narrowband reflectance with TOA broadband albedo determined by NASA's Clouds and the Earth's Radiant Energy System (CERES) instead of Moderate Resolution Imaging Spectroradiometer (MODIS). The TOA albedo product developed in this study has an increased spatial resolution, from 1° to 0.05°, and its starting year has been extended from 2000 to 1981, compared to the CERES TOA albedo product. Models of lands and oceans are established separately under different atmospheric and surface conditions using gradient boosting regression tree (GBRT) method instead of the linear regression models in the previous study. The root mean square errors (RMSEs) of the cloudy-sky, clear-sky and snow-cover models over land are 11.2%, 9.2% and 2.3%, respectively; over oceans they are 14.6%, 10.6% and 5.6%, respectively. Compared to Song et al. (2018), the improvements of the three models over land are 28.8%, 29.2% and 68.6%, respectively. Compared to the CERES product, the new product is much more accurate than that from our previous study. The global monthly mean differences of the TOA albedo obtained with the GBRT product and CERES from 2001 to 2014 are mostly less than 5%. CERES; AVHRR; TOA albedo; Earth's energy budget; Machine learning
Zhang, Honghai; Seager, Richard; Xie, Shang-PingZhang, H., R. Seager, S. Xie, 2022: How Does Sea Surface Temperature Drive the Intertropical Convergence Zone in the Southern Indian Ocean?. J. Climate, 35(16), 5415-5432. doi: 10.1175/JCLI-D-21-0870.1. Abstract The Indian Ocean has an intriguing intertropical convergence zone (ITCZ) south of the equator year-round, which remains largely unexplored. Here we investigate this Indian Ocean ITCZ and the mechanisms for its origin. With a weak semiannual cycle, this ITCZ peaks in January–February with the strongest rainfall and southernmost location and a northeast–southwest orientation from the Maritime Continent to Madagascar, reaches a minimum around May with a zonal orientation, grows until its secondary maximum around September with a northwest–southeast orientation, weakens slightly until December, and then regains its mature phase in January. During austral summer, the Indian Ocean ITCZ exists over maximum surface moist static energy (MSE), consistent with convective quasi-equilibrium theory. This relationship breaks up during boreal summer when the surface MSE maximizes in the northern monsoon region. The position and orientation of the Indian Ocean ITCZ can be simulated well in both a linear dynamical model and the state-of-the-art Community Atmosphere Model version 6 (CAM6) when driven by observed sea surface temperature (SST). To quantify the contributions of the planetary boundary layer (PBL) and free-atmosphere processes to this ITCZ, we homogenize the free-atmosphere diabatic heating over the Indian Ocean in CAM6. In response, the ITCZ weakens significantly, owing to a weakened circulation and deep convection. Therefore, in CAM6, the SST drives the Indian Ocean ITCZ directly through PBL processes and indirectly via free-atmosphere diabatic heating. Their contributions are comparable during most seasons, except during the austral summer when the free-atmosphere diabatic heating dominates the mature-phase ITCZ. Significance Statement The intertropical convergence zone (ITCZ) is the globe-encircling band where trade winds converge and strong rainfall occurs in the tropics. Its rains provide life-supporting water to billions of people. Its associated latent heating invigorates the tropical atmospheric circulation and influences climate and weather across the planet. The ITCZ is located north of the equator in most tropical oceans, except in the Indian Ocean where it sits south of the equator year-around. In contrast to the well-known northern ITCZs, the origin of the southern ITCZ in the Indian Ocean remains unknown. This work provides the first explanation for how ocean surface temperature works together with processes in the lower and upper atmosphere to shape the unique ITCZ in the Indian Ocean.
Zhang, Jianhao; Zhou, Xiaoli; Goren, Tom; Feingold, GrahamZhang, J., X. Zhou, T. Goren, G. Feingold, 2022: Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions. Atmospheric Chemistry and Physics, 22(2), 861-880. doi: 10.5194/acp-22-861-2022. Abstract. Quantification of the radiative adjustment of marine low clouds to aerosol perturbations, regionally and globally, remains the largest source of uncertainty in assessing current and future climate. One of the important steps towards quantifying the role of aerosol in modifying cloud radiative properties is to quantify the susceptibility of cloud albedo and liquid water path (LWP) to perturbations in cloud droplet number concentration (Nd). We use 10 years of spaceborne observations from the polar-orbiting Aqua satellite to quantify the albedo susceptibility of marine low clouds to Nd perturbations over the northeast (NE) Pacific stratocumulus (Sc) region. Mutual information analysis reveals a dominating control of cloud state (e.g., LWP and Nd) on low-cloud albedo susceptibility, relative to the meteorological states that drive these cloud states. Through a LWP–Nd space decomposition of albedo susceptibilities, we show clear separation among susceptibility regimes (brightening or darkening), consistent with previously established mechanisms through which aerosol modulates cloud properties. These regimes include (i) thin non-precipitating clouds (LWP < 55 g m−2) that exhibit brightening (occurring 37 % of the time), corresponding to the Twomey effect; (ii) thicker non-precipitating clouds, corresponding to entrainment-driven negative LWP adjustments that manifest as a darkening regime (36 % of the time); and (iii) another brightening regime (22 % of the time) consisting of mostly precipitating clouds, corresponding to precipitation-suppression LWP positive adjustments. Overall, we find an annual-mean regional low-cloud brightening potential of 20.8±2.68 W m−2 ln(Nd)−1, despite an overall negative LWP adjustment for non-precipitating marine stratocumulus, owing to the high occurrence of the Twomey–brightening regime. Over the NE Pacific, clear seasonal covariabilities among meteorological factors related to the large-scale circulation are found to play an important role in grouping conditions favorable for each susceptibility regime. When considering the covarying meteorological conditions, our results indicate that for the northeastern Pacific stratocumulus, clouds that exhibit the strongest brightening potential occur most frequently within shallow marine boundary layers over a cool ocean surface with a stable atmosphere and a dry free troposphere above. Clouds that exhibit a darkening potential associated with negative LWP adjustments occur most frequently within deep marine boundary layers in which the atmospheric instability and the ocean surface are not strong and warm enough to produce frequent precipitation. Cloud brightening associated with warm-rain suppression is found to preferably occur either under unstable atmospheric conditions or humid free-tropospheric conditions that co-occur with a warm ocean surface.
Zhang, Ke; Zhao, Long; Tang, Wenjun; Yang, Kun; Wang, JingZhang, K., L. Zhao, W. Tang, K. Yang, J. Wang, 2022: Global and Regional Evaluation of the CERES Edition-4A Surface Solar Radiation and Its Uncertainty Quantification. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15, 2971-2985. doi: 10.1109/JSTARS.2022.3164471. This article presents a comprehensive evaluation of the 2000–2018 Clouds and Earth's Radiant Energy System Synoptic 1° Ed4A (CERES SYN1deg Edition 4A) surface solar radiation (SSR) product. In particular, the global assessment is conducted over different temporal scales (i.e., hourly, daily, and monthly-average) with special attention given to the impact of clouds, and a regional evaluation is further implemented over the Mainland of China (MC) using SSR measurements from a denser observational network provided by the China Meteorological Administration. Evaluation across all valid station-grid pairs yields mixed performance with |MBE|≤2.8 (6.2) W m−2, RMSE≤89.5 (31.6) W m−2, and R≥0.95 (0.93) over the globe (MC) for different temporal scales, and the monthly CERES SSR, with RMSE≤20 W m−2, is found to hold promise for global numerical weather prediction and climate monitoring. In addition, CERES is found to generally underestimate and overestimate SSR over land and ocean, respectively. Comparison between year-round and cloudy-season suggests that the presence of clouds may potentially impact the SSR retrievals, especially at the hourly temporal scales, with an increase in RMSE values larger than 10 W m−2 for most stations. Further investigation of subgrid heterogeneity suggests that most in situ SSR measurements can reasonably represent the 1° grid average except for some stations with specific geographic deployments, which may raise significant spatial representativeness issues and, therefore, need to be used with great caution. Earth; Satellites; cloud; Solar radiation; Sea measurements; Sea surface; surface solar radiation; Clouds; uncertainty quantification; Cloud computing; Clouds and Earth's radiant energy system synoptic (CERES); spatial representativeness
Zhang, Kun; Zhu, Gaofeng; Ma, Ning; Chen, Huiling; Shang, ShashaZhang, K., G. Zhu, N. Ma, H. Chen, S. Shang, 2022: Improvement of evapotranspiration simulation in a physically based ecohydrological model for the groundwater–soil–plant–atmosphere continuum. Journal of Hydrology, 613, 128440. doi: 10.1016/j.jhydrol.2022.128440. Accurate quantification of terrestrial evapotranspiration (ET) is essential to understanding the interaction between land and atmosphere, as well as the feedback response of vegetation dynamics. In our previous work, a physically based ecohydrological model called the simple terrestrial hydrosphere (SiTH) model was developed to estimate ET and the other ET-related variables based on the groundwater–soil–plant–atmosphere continuum (GSPAC). However, the SiTH model (SiTHv1) still has some deficiencies in the model structure and parameters, which can result in potential uncertainty in the estimation of terrestrial ET. In this study, we aimed to address these limitations by developing a new version of the SiTH model (SiTHv2). The main modifications of the SiTHv2 model include: (1) the vegetation moisture constraint module is updated with vegetation optical depth observations; (2) the critical model parameters associated with root distribution are constrained using flux observations; (3) the soil module is extended to a three-layer module with 5 m of total depth; (4) an irrigation input water strategy is applied in the cropland areas; and (5) the latest ERA5-Land reanalysis data with a finer spatial resolution are used as the meteorological forcing data. The estimated ET of the SiTHv2 model was validated/compared at multiple scales (i.e., site/plot, basin, and global) with flux data, basin water balance data, and other mainstream global ET products, respectively. The results demonstrate that the SiTHv2 model performs better than the SiTHv1 model, with an improvement in the overall model root-mean-square error of 0.66 mm day−1 (plot scale) and 98.58 mm year−1 (basin scale), representing 27% and 22% improvements over the SiTHv1 model in the same circumstances, respectively. In addition, the performance of the SiTHv2 model ranks well when compared to the existing terrestrial ET models and products. The improvements to the SiTH model should allow improved estimation of terrestrial ET and provide support to potential studies in water transfer within the GSPAC. Evapotranspiration; Water stress; Multi-scale verification; SiTH model
Zhang, Wanchun; Liu, Jian; Zhang, Peng; Sun, Ling; Xu, Hanlie; Wang, Yanjiao; Chen, LinZhang, W., J. Liu, P. Zhang, L. Sun, H. Xu, Y. Wang, L. Chen, 2022: Evaluation of Reprocessed Fengyun-3B Global Outgoing Longwave Radiation Data: Comparison with CERES OLR. Journal of Meteorological Research, 36(3), 417-428. doi: 10.1007/s13351-022-1132-4. Outgoing longwave radiation (OLR) at the top of the atmosphere (TOA) is a key parameter for understanding and interpreting the relationship between clouds, radiation, and climate interactions. It has been one of the operational products of the Fengyun (FY) meteorological satellites. OLR accuracy has gradually improved with advancements in satellite payload performance and the OLR retrieval algorithm. Supported by the National Key R&D Program Retrospective Calibration of Historical Chinese Earth Observation Satellite data (Richceos) project, a long-term OLR climate data record (CDR) was reprocessed based on the recalibrated Level 1 data of FY series satellites using the latest OLR retrieval algorithm. In this study, Fengyun-3B (FY-3B)’s reprocessed global OLR data from 2010 to 2018 were evaluated by using the Clouds and the Earth’s Radiant Energy System (CERES) global daily OLR data. The results showed that there was a high consistency between the FY-3B instantaneous OLR and CERES Single Scanner Footprint (SSF) OLR. Globally, between the two CDR datasets, the correlation coefficient reached 0.98, and the root-mean-square error (RMSE) was approximately 8–9 W m−2. The bias mainly came from the edge regions of the satellite orbit, which may be related to the satellite zenith angle and cloud cover distribution. It was shown that the long-term FY-3B OLR had temporal stability compared to CERES OLR long-term data. In terms of spatial distribution, the mean deviations showed zonal and seasonal characteristics, although seasonal fluctuations were observed in the differences between the two datasets. Effects of FY-3B OLR application to the South China Sea monsoon region and ENSO were demonstrated and analyzed, and the results showed that the seasonal deviation of FY-3B’s OLR comes mainly from the retrieval algorithm. However, it has little effect on the analysis of climate events. Clouds and the Earth’s Radiant Energy System (CERES); El Niño—Southern Oscillation (ENSO); Fengyun-3B (FY-3B); outgoing longwave radiation (OLR); South China Sea monsoon
Zhang, Xiyue; Schneider, Tapio; Shen, Zhaoyi; Pressel, Kyle G.; Eisenman, IanZhang, X., T. Schneider, Z. Shen, K. G. Pressel, I. Eisenman, 2022: Seasonal Cycle of Idealized Polar Clouds: Large Eddy Simulations Driven by a GCM. Journal of Advances in Modeling Earth Systems, 14(1), e2021MS002671. doi: 10.1029/2021MS002671. The uncertainty in polar cloud feedbacks calls for process understanding of the cloud response to climate warming. As an initial step toward improved process understanding, we investigate the seasonal cycle of polar clouds in the current climate by adopting a novel modeling framework using large eddy simulations (LES), which explicitly resolve cloud dynamics. Resolved horizontal and vertical advection of heat and moisture from an idealized general circulation model (GCM) are prescribed as forcing in the LES. The LES are also forced with prescribed sea ice thickness, but surface temperature, atmospheric temperature, and moisture evolve freely without nudging. A semigray radiative transfer scheme without water vapor and cloud feedbacks allows the GCM and LES to achieve closed energy budgets more easily than would be possible with more complex schemes. This enables the mean states in the two models to be consistently compared, without the added complications from interaction with more comprehensive radiation. We show that the LES closely follow the GCM seasonal cycle, and the seasonal cycle of low-level clouds in the LES resembles observations: maximum cloud liquid occurs in late summer and early autumn, and winter clouds are dominated by ice in the upper troposphere. Large-scale advection of moisture provides the main source of water vapor for the liquid-containing clouds in summer, while a temperature advection peak in winter makes the atmosphere relatively dry and reduces cloud condensate. The framework we develop and employ can be used broadly for studying cloud processes and the response of polar clouds to climate warming. cloud; GCM; Arctic; mixed-phase cloud; LES; seasonal cycle
Zhao, Guangyu; Yang, Muqun; Gao, Yizhao; Zhan, Yizhe; Lee, H. Joe; Di Girolamo, LarryZhao, G., M. Yang, Y. Gao, Y. Zhan, H. J. Lee, L. Di Girolamo, 2022: PYTAF: A Python Tool for Spatially Resampling Earth Observation Data. Earth Science Informatics, 15(3), 1443-1448. doi: 10.1007/s12145-020-00461-w. Earth observation data have revolutionized Earth science and significantly enhanced the ability to forecast weather, climate and natural hazards. The storage format of the majority of Earth observation data can be classified into swath, grid or point structures. Earth science studies frequently involve resampling between swath, grid and point data when combining measurements from multiple instruments, which can provide more insights into geophysical processes than using any single instrument alone. As the amount of Earth observation data increases each day, the demand for a high computational efficient tool to resample and fuse Earth observation data has never been greater. We present a software tool, called pytaf, that resamples Earth observation data stored in swath, grid or point structures using a novel block indexing algorithm. This tool is specially designed to process large scale datasets. The core functions of pytaf were implemented in C with OpenMP to enable parallel computations in a shared memory environment. A user-friendly python interface was also built. The tool has been extensively tested on supercomputers and successfully used to resample the data from five instruments on the EOS-Terra platform at a mission-wide scale. Grid; Nearest Neighbor; Pytaf; Python; Resample; Swath
Zhao, Lijun; Wang, Yuan; Zhao, Chuanfeng; Dong, Xiquan; Yung, Yuk L.Zhao, L., Y. Wang, C. Zhao, X. Dong, Y. L. Yung, 2022: Compensating Errors in Cloud Radiative and Physical Properties over the Southern Ocean in the CMIP6 Climate Models. Advances in Atmospheric Sciences. doi: 10.1007/s00376-022-2036-z. The Southern Ocean is covered by a large amount of clouds with high cloud albedo. However, as reported by previous climate model intercomparison projects, underestimated cloudiness and overestimated absorption of solar radiation (ASR) over the Southern Ocean lead to substantial biases in climate sensitivity. The present study revisits this long-standing issue and explores the uncertainty sources in the latest CMIP6 models. We employ 10-year satellite observations to evaluate cloud radiative effect (CRE) and cloud physical properties in five CMIP6 models that provide comprehensive output of cloud, radiation, and aerosol. The simulated longwave, shortwave, and net CRE at the top of atmosphere in CMIP6 are comparable with the CERES satellite observations. Total cloud fraction (CF) is also reasonably simulated in CMIP6, but the comparison of liquid cloud fraction (LCF) reveals marked biases in spatial pattern and seasonal variations. The discrepancies between the CMIP6 models and the MODIS satellite observations become even larger in other cloud macro- and micro-physical properties, including liquid water path (LWP), cloud optical depth (COD), and cloud effective radius, as well as aerosol optical depth (AOD). However, the large underestimation of both LWP and cloud effective radius (regional means ∼20% and 11%, respectively) results in relatively smaller bias in COD, and the impacts of the biases in COD and LCF also cancel out with each other, leaving CRE and ASR reasonably predicted in CMIP6. An error estimation framework is employed, and the different signs of the sensitivity errors and biases from CF and LWP corroborate the notions that there are compensating errors in the modeled shortwave CRE. Further correlation analyses of the geospatial patterns reveal that CF is the most relevant factor in determining CRE in observations, while the modeled CRE is too sensitive to LWP and COD. The relationships between cloud effective radius, LWP, and COD are also analyzed to explore the possible uncertainty sources in different models. Our study calls for more rigorous calibration of detailed cloud physical properties for future climate model development and climate projection. cloud physics; cloud radiative effect; global climate models; the Southern Ocean
Zheng, Cheng; Ting, Mingfang; Wu, Yutian; Kurtz, Nathan; Orbe, Clara; Alexander, Patrick; Seager, Richard; Tedesco, MarcoZheng, C., M. Ting, Y. Wu, N. Kurtz, C. Orbe, P. Alexander, R. Seager, M. Tedesco, 2022: Turbulent Heat Flux, Downward Longwave Radiation, and Large-Scale Atmospheric Circulation Associated with Wintertime Barents–Kara Sea Extreme Sea Ice Loss Events. J. Climate, 35(12), 3747-3765. doi: 10.1175/JCLI-D-21-0387.1. Abstract We investigate wintertime extreme sea ice loss events on synoptic to subseasonal time scales over the Barents–Kara Sea, where the largest sea ice variability is located. Consistent with previous studies, extreme sea ice loss events are associated with moisture intrusions over the Barents–Kara Sea, which are driven by the large-scale atmospheric circulation. In addition to the role of downward longwave radiation associated with moisture intrusions, which is emphasized by previous studies, our analysis shows that strong turbulent heat fluxes are associated with extreme sea ice melting events, with both turbulent sensible and latent heat fluxes contributing, although turbulent sensible heat fluxes dominate. Our analysis also shows that these events are connected to tropical convective anomalies. A dipole pattern of convective anomalies with enhanced convection over the Maritime Continent and suppressed convection over the central to eastern Pacific is consistently detected about 6–10 days prior to extreme sea ice loss events. This pattern is associated with either the Madden–Julian oscillation (MJO) or El Niño–Southern Oscillation (ENSO). Composites show that extreme sea ice loss events are connected to tropical convection via Rossby wave propagation in the midlatitudes. However, tropical convective anomalies alone are not sufficient to trigger extreme sea ice loss events, suggesting that extratropical variability likely modulates the connection between tropical convection and extreme sea ice loss events.
Zhou, Hao; Yue, Xu; Lei, Yadong; Tian, Chenguang; Zhu, Jun; Ma, Yimian; Cao, Yang; Yin, Xixi; Zhang, ZhidingZhou, H., X. Yue, Y. Lei, C. Tian, J. Zhu, Y. Ma, Y. Cao, X. Yin, Z. Zhang, 2022: Distinguishing the impacts of natural and anthropogenic aerosols on global gross primary productivity through diffuse fertilization effect. Atmospheric Chemistry and Physics, 22(1), 693-709. doi: 10.5194/acp-22-693-2022. Abstract. Aerosols can enhance ecosystem productivity by increasing diffuse radiation. Such diffuse fertilization effects (DFEs) vary among different aerosol compositions and sky conditions. Here, we apply a suite of chemical, radiation, and vegetation models in combination with ground- and satellite-based measurements to assess the impacts of natural and anthropogenic aerosol species on gross primary productivity (GPP) through DFE from 2001–2014. Globally, aerosols enhance GPP by 8.9 Pg C yr−1 under clear-sky conditions but only 0.95 Pg C yr−1 under all-sky conditions. Anthropogenic aerosols account for 41 % of the total GPP enhancement, though they contribute only 25 % to the increment of diffuse radiation. Sulfate/nitrate aerosols from anthropogenic sources make dominant contributions of 33 % (36 %) to aerosol DFE under all-sky (clear-sky) conditions, followed by the fraction of 18 % (22 %) by organic carbon aerosols from natural sources. In contrast to other species, black carbon aerosols reduce global GPP by 0.28 (0.12) Pg C yr−1 under all-sky (clear-sky) conditions. Long-term simulations show that aerosol DFE increases 2.9 % yr−1 under all-sky conditions mainly because of a downward trend in cloud amount. This study suggests that the impacts of aerosols and cloud should be considered in projecting future changes of ecosystem productivity under varied emission scenarios.
Zhou, Xingyu; Chen, Hua; Jiang, Weiping; Chen, Yan; Jin, Taoyong; Liu, Tianjun; Gao, YangZhou, X., H. Chen, W. Jiang, Y. Chen, T. Jin, T. Liu, Y. Gao, 2022: A new ambiguity resolution method for LEO precise orbit determination. Journal of Geodesy, 96(7), 49. doi: 10.1007/s00190-022-01629-6. Ambiguity resolution (AR) is an effective approach to improve the orbit accuracy of the low Earth orbit satellites using the Global Navigation Satellite System (GNSS). The most commonly used single-difference (SD) AR requires prior knowledge of the GNSS hardware biases, while the potential unavailability of the bias products may hinder the AR process for users. The track-to-track (T2T) AR can work as an alternative without the GNSS bias products, but the performance may be degraded by the receiver hardware biases. To provide a better alternative in this condition, a new AR method called SD T2T (SDT2T) is proposed in this study, where the GNSS and receiver biases can be greatly eliminated without external knowledge. The performance of the SD AR, SDT2T AR, and T2T AR methods are assessed based on the gravity recovery and climate experiment follow on and SWARM data. The results show that the improvements contributed by the SDT2T AR are comparable to the SD AR. The multiple iterations required by the T2T AR can be avoided by the SDT2T AR, and the accuracy of the T2T AR can be further improved with the preprocessed ambiguities of the SDT2T AR. Considering the efficiency and stable performance, the SDT2T AR is recommended as the preferred alternative single-receiver AR method in the absence of the GNSS hardware bias products. Ambiguity resolution; K-band range validation; LEO; Precise orbit determination; SLR orbit validation
Zhu, Fuxin; Li, Xin; Qin, Jun; Yang, Kun; Cuo, Lan; Tang, Wenjun; Shen, ChaopengZhu, F., X. Li, J. Qin, K. Yang, L. Cuo, W. Tang, C. Shen, 2022: Integration of Multisource Data to Estimate Downward Longwave Radiation Based on Deep Neural Networks. IEEE Transactions on Geoscience and Remote Sensing, 60, 1-15. doi: 10.1109/TGRS.2021.3094321. Downward longwave radiation (DLR) at the surface is a key variable of interest in fields, such as hydrology and climate research. However, existing DLR estimation methods and DLR products are still problematic in terms of both accuracy and spatiotemporal resolution. In this article, we propose a deep convolutional neural network (DCNN)-based method to estimate hourly DLR at 5-km spatial resolution from top of atmosphere (TOA) brightness temperature (BT) of the Himawari-8/Advanced Himawari Imager (AHI) thermal channels, combined with near-surface air temperature and dew point temperature of ERA5 and elevation data. Validation results show that the DCNN-based method outperforms popular random forest and multilayer perceptron-based methods and that our proposed scheme integrating multisource data outperforms that only using remote sensing TOA observations or surface meteorological data. Compared with state-of-the-art CERES-SYN and ERA5-land DLR products, the estimated DLR by our proposed DCNN-based method with physical multisource inputs has higher spatiotemporal resolution and accuracy, with correlation coefficient (CC) of 0.95, root-mean-square error (RMSE) of 17.2 W/m2, and mean bias error (MBE) of −0.8 W/m2 in the testing period on the Tibetan Plateau. Land surface; Atmospheric modeling; Ocean temperature; Spatial resolution; Himawari-8; Clouds; Temperature distribution; Deep convolutional neural network (DCNN); downward longwave radiation (DLR); Estimation; Tibetan Plateau (TP)
Zhu, Jiang; Otto-Bliesner, Bette L.; Brady, Esther C.; Gettelman, Andrew; Bacmeister, Julio T.; Neale, Richard B.; Poulsen, Christopher J.; Shaw, Jonah K.; McGraw, Zachary S.; Kay, Jennifer E.Zhu, J., B. L. Otto-Bliesner, E. C. Brady, A. Gettelman, J. T. Bacmeister, R. B. Neale, C. J. Poulsen, J. K. Shaw, Z. S. McGraw, J. E. Kay, 2022: LGM paleoclimate constraints inform cloud parameterizations and equilibrium climate sensitivity in CESM2. Journal of Advances in Modeling Earth Systems, n/a(n/a), e2021MS002776. doi: 10.1029/2021MS002776. The Community Earth System Model version 2 (CESM2) simulates a high equilibrium climate sensitivity (ECS > 5°C) and a Last Glacial Maximum (LGM) that is substantially colder than proxy temperatures. In this study, we examine the role of cloud parameterizations in simulating the LGM cooling in CESM2. Through substituting different versions of cloud schemes in the atmosphere model, we attribute the excessive LGM cooling to the new CESM2 schemes of cloud microphysics and ice nucleation. Further exploration suggests that removing an inappropriate limiter on cloud ice number (NoNimax) and decreasing the time-step size (substepping) in cloud microphysics largely eliminate the excessive LGM cooling. NoNimax produces a more physically consistent treatment of mixed-phase clouds, which leads to an increase in cloud ice content and a weaker shortwave cloud feedback over mid-to-high latitudes and the Southern Hemisphere subtropics. Microphysical substepping further weakens the shortwave cloud feedback. Based on NoNimax and microphysical substepping, we have developed a paleoclimate-calibrated CESM2 (PaleoCalibr), which simulates well the observed 20th century warming and spatial characteristics of key cloud and climate variables. PaleoCalibr has a lower ECS (∼4°C) and a 20% weaker aerosol-cloud interaction than CESM2. PaleoCalibr represents a physically more consistent treatment of cloud microphysics than CESM2 and is a valuable tool in climate change studies, especially when a large climate forcing is involved. Our study highlights the unique value of paleoclimate constraints in informing the cloud parameterizations and ultimately the future climate projection. Cloud parameterizations; Cloud feedback; Community Earth System Model version 2; Equilibrium Climate Sensitivity; Last Glacial Maximum
## 2021
Aldhaif, Abdulmonam M.; Lopez, David H.; Dadashazar, Hossein; Painemal, David; Peters, Andrew J.; Sorooshian, ArminAldhaif, A. M., D. H. Lopez, H. Dadashazar, D. Painemal, A. J. Peters, A. Sorooshian, 2021: An Aerosol Climatology and Implications for Clouds at a Remote Marine Site: Case Study Over Bermuda. Journal of Geophysical Research: Atmospheres, 126(9), e2020JD034038. doi: https://doi.org/10.1029/2020JD034038. Aerosol characteristics and aerosol–cloud interactions remain uncertain in remote marine regions. We use over a decade of data (2000–2012) from the NASA AErosol RObotic NETwork, aerosol and wet deposition samples, satellite remote sensors, and models to examine aerosol and cloud droplet number characteristics at a representative open ocean site (Bermuda) over the Western North Atlantic Ocean (WNAO). Annual mean values were as follows: aerosol optical depth (AOD) = 0.12, Ångström Exponent (440/870 nm) = 0.95, fine mode fraction = 0.51, asymmetry factor = 0.72 (440 nm) and 0.68 (1020 nm), and Aqua-MODIS cloud droplet number concentrations = 51.3 cm−3. The winter season (December–February) was characterized by high sea salt optical thickness and the highest aerosol extinction in the lowest 2 km. Extensive precipitation over the WNAO in winter helps contribute to the low FMFs in winter (∼0.40–0.50) even though air trajectories often originate over North America. Spring and summer had more pronounced influence from sulfate, dust, organic carbon, and black carbon. Volume size distributions were bimodal with a dominant coarse mode (effective radii: 1.85–2.09 µm) and less pronounced fine mode (0.14–0.16 µm), with variability in the coarse mode likely due to different characteristic sizes for transported dust (smaller) versus regional sea salt (larger). Extreme pollution events highlight the sensitivity of this site to long-range transport of urban emissions, dust, and smoke. Differing annual cycles are identified between AOD and cloud droplet number concentrations, motivating a deeper look into aerosol–cloud interactions at this site. aerosol; ACTIVATE; sea salt; African dust; Bermuda; EVS-3
Alexandri, Georgia; Georgoulias, Aristeidis K.; Balis, DimitrisAlexandri, G., A. K. Georgoulias, D. Balis, 2021: Effect of Aerosols, Tropospheric NO2 and Clouds on Surface Solar Radiation over the Eastern Mediterranean (Greece). Remote Sensing, 13(13), 2587. doi: 10.3390/rs13132587. In this work, the effect that two basic air quality indexes, aerosols and tropospheric NO2, exert on surface solar radiation (SSR) is studied, along with the effect of liquid and ice clouds over 16 locations in Greece, in the heart of the Eastern Mediterranean. State-of-the-art satellite-based observations and climatological data for the 15-year period 2005–2019, and a radiative transfer system based on a modified version of the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model are used. Our SSR simulations are in good agreement with ground observations and two satellite products. It is shown that liquid clouds dominate, with an annual radiative effect (RE) of −36 W/m2, with ice clouds (−19 W/m2) and aerosols (−13 W/m2) following. The radiative effect of tropospheric NO2 is smaller by two orders of magnitude (−0.074 W/m2). Under clear skies, REaer is about 3–4 times larger than for liquid and ice cloud-covered skies, while RENO2 doubles. The radiative effect of all the parameters exhibits a distinct seasonal cycle. An increase in SSR is observed for the period 2005–2019 (positive trends ranging from 0.01 to 0.52 W/m2/year), which is mostly related to a decrease in the aerosol optical depth and the liquid cloud fraction. clouds; aerosols; CERES; MODIS; surface solar radiation; CALIPSO; CM SAF; SBDART; Greece; tropospheric NO2
Arouf, Assia; Chepfer, Hélène; Vaillant de Guélis, Thibault; Chiriaco, Marjolaine; Shupe, Matthew D.; Guzman, Rodrigo; Feofilov, Artem; Raberanto, Patrick; L’Ecuyer, Tristan S.; Kato, Seiji; Gallagher, Michael R.Arouf, A., H. Chepfer, T. Vaillant de Guélis, M. Chiriaco, M. D. Shupe, R. Guzman, A. Feofilov, P. Raberanto, T. S. L’Ecuyer, S. Kato, M. R. Gallagher, 2021: The Surface Longwave Cloud Radiative Effect derived from Space Lidar Observations. Atmospheric Measurement Techniques Discussions, 1-54. doi: 10.5194/amt-2021-392. Abstract. Clouds warm the surface in the longwave (LW) and this warming effect can be quantified through the surface LW cloud radiative effect (CRE). The global surface LW CRE is estimated using long-term observations from space-based radiometers (2000–2021) but has some bias over continents and icy surfaces. It is also estimated globally using the combination of radar, lidar and space-based radiometer over the 5–year period ending in 2011. To develop a more reliable long time series of surface LW CRE over continental and icy surfaces, we propose new estimates of the global surface LW CRE from space-based lidar observations. We show from 1D atmospheric column radiative transfer calculations, that surface LW CRE linearly decreases with increasing cloud altitude. These computations allow us to establish simple relationships between surface LW CRE, and five cloud properties that are well observed by the CALIPSO space-based lidar: opaque cloud cover and altitude, and thin cloud cover, altitude, and emissivity. We use these relationships to retrieve the surface LW CRE at global scale over the 2008–2020 time period (27 Wm−2). We evaluate this new surface LW CRE product by comparing it to existing satellite-derived products globally on instantaneous collocated data at footprint scale and on global averages, as well as to ground-based observations at specific locations. Our estimate appears to be an improvement over others as it appropriately capture the surface LW CRE annual variability over bright polar surfaces and it provides a dataset of more than 13 years long.
Arya, V. B.; Surendran, Sajani; Rajendran, KavirajanArya, V. B., S. Surendran, K. Rajendran, 2021: On the build-up of dust aerosols and possible indirect effect during Indian summer monsoon break spells using recent satellite observations of aerosols and cloud properties. Journal of Earth System Science, 130(1), 42. doi: 10.1007/s12040-020-01526-6. Association of higher (lower) rainfall with lower (higher) Aerosol Optical Depth (AOD) is consistent with the understanding that increased washout (build-up) and shorter (longer) life-time of aerosols occur in wetter (drier) conditions. Given the life-time of aerosols, it is imperative to examine how aerosols impact active/break (wetter/drier than normal) spells, prominent intraseasonal variability (ISV) of Indian summer monsoon (ISM), through their composite analysis using recent satellite observations of aerosols and cloud properties, circulation and rainfall. Dust aerosols can act as CCN and participate efficiently in cloud processes during active phase. During breaks, build-up of desert dust transported by prevalent circulation, is associated with lower cloud effective radius implying aerosols’ indirect effect where they can inhibit cloud growth in the presence of reduced moisture and decrease precipitation efficiency/rainfall. Correspondingly, correlation albeit small, between intraseasonal anomalies of AOD and rainfall is negative, when AOD leads rainfall by 3–5 days implying that indirect aerosols impact is effective during breaks, though it is not the dominant responsible factor. During breaks, lower shortwave flux at top of atmosphere hints at dust-induced semi-direct effect. As breaks are permanent features of ISM, incorporation of dust-induced feedbacks in models, is essential for improved ISV simulation and ISM prediction.
Attada, Raju; Kunchala, Ravi Kumar; Dasari, Hari Prasad; Sivareddy, Sanikommu; Yesubabu, Viswanadhapalli; Knio, Omar; Hoteit, IbrahimAttada, R., R. K. Kunchala, H. P. Dasari, S. Sivareddy, V. Yesubabu, O. Knio, I. Hoteit, 2021: Representation of Arabian Peninsula summer climate in a regional atmospheric model using spectral nudging. Theoretical and Applied Climatology, 145(1), 13-30. doi: 10.1007/s00704-021-03617-w. This study assesses the performance of the Weather Research and Forecasting (WRF) model in simulating the Arabian Peninsula summer climate for the period 2001–2016. The European Centre for Medium range Weather Forecast (ECMWF) reanalysis is downscaled using WRF without (CTRL) and with the Spectral Nudging (SPN) method. Our results suggest that the noticeable cold biases in surface temperatures (mean, minimum, and maximum) over the Arabian Peninsula in CTRL are significantly reduced in SPN. The seasonal patterns of surface pressure, cloud cover, lower and upper tropospheric circulation, and mid-tropospheric anticyclone are also simulated more realistically with SPN. The evaluation of mean vertical profiles of dynamical and thermo-dynamical features over the Arabian Peninsula further confirms the enhanced simulations with SPN with respect to CTRL. Though SPN captures better the observed evolution of rainfall compared to that of CTRL, it produces a positive rainfall bias over the Southwestern Arabian Peninsula. Stronger vertical motions associated with the local topography enhance the higher water vapor loading, condenses in the upper layers, and results in excess amount of rainfall in SPN. Furthermore, with SPN, WRF is further able to better simulate the synoptic features of heat waves. Overall, SPN enhances WRF simulation skill of the horizontal structures and vertical profiles of the Arabian Peninsula summer climate by enforcing a better balance between the small and large scale features and associated feedbacks.
Baba, YuyaBaba, Y., 2021: Improved intraseasonal variability in the initialization of SINTEX-F2 using a spectral cumulus parameterization. International Journal of Climatology, 41(15), 6690-6712. doi: 10.1002/joc.7220. A newly developed spectral cumulus parameterization (spectral scheme) was implemented in the Scale Interaction Experiment-Frontier version 2 (SINTEX-F2) seasonal prediction system to improve intraseasonal variability in the system initialization. A simple sea surface temperature (SST) nudging scheme using different SST data and restoring times was used to initialize the system, and the initialized atmosphere obtained from both the original convection scheme (Tiedtke scheme) and the new spectral scheme was evaluated against observational data. It was found that that climatology and variability simulated by the spectral scheme were comparable to those simulated by the original scheme. In addition, the intraseasonal variability represented by the Madden–Julian oscillation (MJO) was better simulated by the spectral scheme than the original scheme. An analysis of the structure of the organized convection revealed the successful simulation of low-level shallow convection before the peak of the organized convection by the spectral scheme when compared with the observation, a result lacking in the original scheme simulation. In addition to the positive qualitative results, a statistical and quantitative analysis showed that the spectral scheme captured the MJO-related variability better than the original scheme. In conclusion, the prediction system using the spectral scheme is expected to improve seasonal predictions for seasonal variability whose evolution is affected by intraseasonal variations. atmosphere; convection; tropics; climate; general circulation model experiments; seasonal prediction
Balaguru, Karthik; Roekel, Luke P. Van; Leung, L. Ruby; Veneziani, MilenaBalaguru, K., L. P. V. Roekel, L. R. Leung, M. Veneziani, 2021: Subtropical Eastern North Pacific SST Bias in Earth System Models. Journal of Geophysical Research: Oceans, 126(8), e2021JC017359. doi: 10.1029/2021JC017359. This study systematically evaluates the warm sea surface temperature (SST) bias in the Subtropical Eastern North Pacific, a problem plaguing most Coupled Model Intercomparison Project Phase 6 models, using the Energy Exascale Earth System Model version 1 (E3SM). In the model at its standard resolution (1° atmosphere, 30–60 km ocean), the SST bias, exceeding several degrees, is mainly concentrated along the coast between 25°N and 40°N. In the high-resolution (0.25° atmosphere, 18–6 km ocean) version of the model, the nearshore SST bias improves considerably with a better representation of coastal upwelling. However, the offshore SST bias, approximately centered at 125°W and 25°N, is relatively stronger in the high-resolution version. To better understand the offshore warm bias in the model, a mixed-layer heat budget analysis is performed. While errors in surface radiative fluxes occur at both resolutions, positive biases in horizontal heat advection also play a role in the SST bias at high-resolution. Analysis of HighResMIP models indicates that the shift in the location of the prominent SST bias from nearshore to offshore with an increase in model spatial resolution, is not native to E3SM alone. CMIP6; coupled climate models; Eastern Pacific; large-scale circulation; mixed-layer heat budget; SST biases
Benjamin, Stanley G.; James, Eric P.; Hu, Ming; Alexander, Curtis R.; Ladwig, Therese T.; Brown, John M.; Weygandt, Stephen S.; Turner, David D.; Minnis, Patrick; Smith, William L.; Heidinger, Andrew K.Benjamin, S. G., E. P. James, M. Hu, C. R. Alexander, T. T. Ladwig, J. M. Brown, S. S. Weygandt, D. D. Turner, P. Minnis, W. L. Smith, A. K. Heidinger, 2021: Stratiform Cloud-Hydrometeor Assimilation for HRRR and RAP Model Short-Range Weather Prediction. Mon. Wea. Rev., 149(8), 2673-2694. doi: 10.1175/MWR-D-20-0319.1. AbstractAccurate cloud and precipitation forecasts are a fundamental component of short-range data assimilation/model prediction systems such as the NOAA 3-km High-Resolution Rapid Refresh (HRRR) or the 13-km Rapid Refresh (RAP). To reduce cloud and precipitation spinup problems, a nonvariational assimilation technique for stratiform clouds was developed within the Gridpoint Statistical Interpolation (GSI) data assimilation system. One goal of this technique is retention of observed stratiform cloudy and clear 3D volumes into the subsequent model forecast. The cloud observations used include cloud-top data from satellite brightness temperatures, surface-based ceilometer data, and surface visibility. Quality control, expansion into spatial information content, and forward operators are described for each observation type. The projection of data from these observation types into an observation-based cloud-information 3D gridded field is accomplished via identification of cloudy, clear, and cloud-unknown 3D volumes. Updating of forecast background fields is accomplished through clearing and building of cloud water and cloud ice with associated modifications to water vapor and temperature. Impact of the cloud assimilation on short-range forecasts is assessed with a set of retrospective experiments in warm and cold seasons using the RAPv5 model. Short-range (1–9 h) forecast skill is improved in both seasons for cloud ceiling and visibility and for 2-m temperature in daytime and with mixed results for other measures. Two modifications were introduced and tested with success: use of prognostic subgrid-scale cloud fraction to condition cloud building (in response to a high bias) and removal of a WRF-based rebalancing.
Bhatt, Rajendra; Doelling, David R.; Coddington, Odele; Scarino, Benjamin; Gopalan, Arun; Haney, ConorBhatt, R., D. R. Doelling, O. Coddington, B. Scarino, A. Gopalan, C. Haney, 2021: Quantifying the Impact of Solar Spectra on the Inter-Calibration of Satellite Instruments. Remote Sensing, 13(8), 1438. doi: 10.3390/rs13081438. In satellite-based remote sensing applications, the conversion of the sensor recorded top-of-atmosphere reflectance to radiance, or vice-versa, is carried out using a reference spectral solar irradiance (SSI) dataset. The choice of reference SSI spectrum has consistently changed over the past four decades with the increasing availability of more accurate SSI measurements with greater spectral coverage. Considerable differences (up to 15% at certain wavelengths) exist between the numerous SSI spectra that are currently being used in satellite ground processing systems. The aim of this study is to quantify the absolute differences between the most commonly used SSI datasets and investigate their impact in satellite inter-calibration and environmental retrievals. It was noted that if analogous SNPP and NOAA-20 VIIRS channel reflectances were perfectly inter-calibrated, the derived channel radiances can still differ by up to 3% due to the utilization of differing SSI datasets by the two VIIRS instruments. This paper also highlights a TSIS-1 SIM-based Hybrid Solar Reference Spectrum (HSRS) with an unprecedented absolute accuracy of 0.3% between 460 and 2365 nm, and recommends that the remote sensing community use it as a common reference SSI in satellite retrievals. calibration; solar spectra; VIIRS; solar constant; TSIS-1 SIM
Blanchard, Yann; Pelon, Jacques; Cox, Christopher J.; Delanoë, Julien; Eloranta, Edwin W.; Uttal, TanielBlanchard, Y., J. Pelon, C. J. Cox, J. Delanoë, E. W. Eloranta, T. Uttal, 2021: Comparison of TOA and BOA LW Radiation Fluxes Inferred From Ground-Based Sensors, A-Train Satellite Observations and ERA Reanalyzes at the High Arctic Station Eureka Over the 2002–2020 Period. Journal of Geophysical Research: Atmospheres, 126(11), e2020JD033615. doi: 10.1029/2020JD033615. This study focuses on the accuracy of longwave radiation flux retrievals at the top and bottom of the atmosphere at Eureka station, Canada, in the high Arctic. We report comparisons between seven products derived from (a) calculations based on a combination of ground-based and space-based lidar and radar observations, (b) standard radiometric observations from the CERES sensor, (c) direct observations at the surface from a broadband radiation station, and (d) the ERA-Interim and ERA5 reanalyzes. Statistical, independent analyses are first performed to look at recurring bias and trends in fluxes at Top and Bottom of the Atmosphere (TOA, BOA). The analysis is further refined by comparing fluxes derived from coincident observations decomposed by scene types. Results show that radiative transfer calculations using ground-based lidar-radar profiles derived at Eureka agree well with TOA LW fluxes observed by CERES and with BOA LW fluxes reference. CloudSat-CALIPSO also shows good agreement with calculations from ground-based sensor observations, with a relatively small bias. This bias is shown to be largely due to low and thick cloud occurrences that the satellites are insensitive to owing to attenuation from clouds above and surface clutter. These conditions of opaque low clouds, cause an even more pronounced bias for CERES BOA flux calculation in winter, due to the deficit of low clouds identified by MODIS. ERA-I and ERA5 fluxes behave differently, the large positive bias observed with ERA-I is much reduced in ERA5. ERA5 is closer to reference observations due to better behavior of low and mid-level clouds and surface temperature. clouds; radiation; satellite data; intercomparison; high Arctic; re-analyses
Blossey, Peter N.; Bretherton, Christopher S.; Mohrmann, JohannesBlossey, P. N., C. S. Bretherton, J. Mohrmann, 2021: Simulating Observed Cloud Transitions in the Northeast Pacific during CSET. Mon. Wea. Rev., 149(8), 2633-2658. doi: 10.1175/MWR-D-20-0328.1. AbstractThe goal of this study is to challenge a large-eddy simulation model with a range of observations from a modern field campaign and to develop case studies useful to other modelers. The 2015 Cloud System Evolution in the Trades (CSET) field campaign provided a wealth of in situ and remote sensing observations of subtropical cloud transitions in the summertime northeast Pacific. Two Lagrangian case studies based on these observations are used to validate the thermodynamic, radiative, and microphysical properties of large-eddy simulations (LES) of the stratocumulus to cumulus transition. The two cases contrast a relatively fast cloud transition in a clean, initially well-mixed boundary layer versus a slower transition in an initially decoupled boundary layer with higher aerosol concentrations and stronger mean subsidence. For each case, simulations of two neighboring trajectories sample mesoscale variability and the coherence of the transition in adjacent air masses. In both cases, LES broadly reproduce satellite and aircraft observations of the transition. Simulations of the first case match observations more closely than for the second case, where simulations underestimate cloud cover early in the simulations and overestimate cloud top height later. For the first case, simulated cloud fraction and liquid water path increase if a larger cloud droplet number concentration is prescribed. In the second case, precipitation onset and inversion cloud breakup occur earlier when the LES domain is chosen to be large enough to support strong mesoscale organization.
Bloxam, Kevin; Huang, YiBloxam, K., Y. Huang, 2021: Radiative Relaxation Time Scales Quantified from Sudden Stratospheric Warmings. Journal of Atmospheric Sciences, 78(1), 269-286. doi: 10.1175/JAS-D-20-0015.1. AbstractSudden stratospheric warmings (SSWs) are impressive events that occur in the winter hemisphere’s polar stratosphere and are capable of producing temperature anomalies upward of +50 K within a matter of days. While much work has been dedicated toward determining how SSWs occur and their ability to interact with the underlying troposphere, one underexplored aspect is the role of radiation, especially during the recovery phase of SSWs. Using a radiative transfer model and a heating rate analysis for distinct layers of the stratosphere averaged over the 60°–90°N polar region, this paper accounts for the radiative contribution to the removal of the anomalous temperatures associated with SSWs. In total 17 events are investigated over the 1979–2016 period. This paper reveals that in the absence of dynamical heating following major SSWs, longwave radiative cooling dominates and often results in a strong negative temperature anomaly. The polar winter stratospheric temperature change driven by the radiative cooling is characterized by an exponential decay of temperature with an increasing e-folding time of 5.7 ± 2.0 to 14.6 ± 4.4 days from the upper to middle stratosphere. The variability of the radiative relaxation rates among the SSWs was determined to be most impacted by the initial temperature of the stratosphere and the combined dynamic and solar heating rates following the onset of the events. We also found that trace-gas anomalies have little impact on the radiative heating rates and the temperature evolution during the SSWs in the mid- to upper stratosphere.
Bogenschutz, Peter A.; Yamaguchi, Takanobu; Lee, Hsiang-HeBogenschutz, P. A., T. Yamaguchi, H. Lee, 2021: The Energy Exascale Earth System Model Simulations With High Vertical Resolution in the Lower Troposphere. Journal of Advances in Modeling Earth Systems, 13(6), e2020MS002239. doi: 10.1029/2020MS002239. General circulation models (GCMs) are typically run with coarse vertical resolution. For example, the Energy Exascale Earth System Model (E3SM) has a vertical resolution of about 200 m in the boundary layer, which is far too coarse to resolve sharp gradients often found in the thermodynamic fields capping subtropical marine stratocumulus. In this article, we present a series of multiyear atmosphere only simulations of E3SM version 1 where we progressively increase the vertical resolution in the lower troposphere to scales approaching those often used in large eddy simulation (LES). We report marginal impacts in regards to the simulation of boundary layer clouds when vertical resolution is moderately increased, yet find significant positive impacts when the vertical resolution approaches that typically used in LES (∼10 m). In these experiments, there is a marked change in the simulated turbulence and thermodynamics which leads to more abundant marine stratocumulus. However, these simulations are burdened with excessive computational cost. They are also subject to degradations in overall climate metrics due to time step sensitivities and because some processes and parameterizations are sensitive to changes in the vertical resolution.
Boudala, Faisal S.; Milbrandt, Jason A.Boudala, F. S., J. A. Milbrandt, 2021: Evaluations of the Climatologies of Three Latest Cloud Satellite Products Based on Passive Sensors (ISCCP-H, Two CERES) against the CALIPSO-GOCCP. Remote Sensing, 13(24), 5150. doi: 10.3390/rs13245150. In this study, the climatologies of three different satellite cloud products, all based on passive sensors (CERES Edition 4.1 [EBAF4.1 and SYN4.1] and ISCCP–H), were evaluated against the CALIPSO-GOCCP (GOCCP) data, which are based on active sensors and, hence, were treated as the reference. Based on monthly averaged data (ocean + land), the passive sensors underestimated the total cloud cover (TCC) at lower (TCC < 50%), but, overall, they correlated well with the GOCCP data (r = 0.97). Over land, the passive sensors underestimated the TCC, with a mean difference (MD) of −2.6%, followed by the EBAF4.1 and ISCCP-H data with a MD of −2.0%. Over the ocean, the CERES-based products overestimated the TCC, but the SYN4.1 agreed better with the GOCCP data. The ISCCP-H data on average underestimated the TCC both over oceanic and continental regions. The annual mean TCC distribution over the globe revealed that the passive sensors generally underestimated the TCC over continental dry regions in northern Africa and southeastern South America as compared to the GOCCP, particularly over the summer hemisphere. The CERES datasets overestimated the TCC over the Pacific Islands between the Indian and eastern Pacific Oceans, particularly during the winter hemisphere. The ISCCP-H data also underestimated the TCC, particularly over the southern hemisphere near 60° S where the other datasets showed a significantly enhanced TCC. The ISCCP data also showed less TCC when compared against the GOCCP data over the tropical regions, particularly over the southern Pacific and Atlantic Oceans near the equator and also over the polar regions where the satellite retrieval using the passive sensors was generally much more challenging. The calculated global mean root meant square deviation value for the ISCCP-H data was 6%, a factor of 2 higher than the CERES datasets. Based on these results, overall, the EBAF4.1 agreed better with the GOCCP data. CERES; satellite remote sensing; ISCCP; CALIPSO; active and passive sensors; cloud cover 2
Bouniol, D.; Guichard, F.; Barbier, J.; Couvreux, F.; Roehrig, R.Bouniol, D., F. Guichard, J. Barbier, F. Couvreux, R. Roehrig, 2021: Sahelian Heat Wave Characterization From Observational Data Sets. Journal of Geophysical Research: Atmospheres, 126(11), e2020JD034465. doi: 10.1029/2020JD034465. This paper makes use of spaceborne observational data sets in order to characterize radiative processes involved in spring time heat waves in the Sahel. Spring corresponds to the hottest period of the year, with a high aerosol load, a gradual moistening, and the presence of clouds contributing to greenhouse effect. Heat waves are defined as synoptic events that have a large spatial extent and a duration longer than 3 days. Two types of heat waves are studied: daytime heat waves, detected with the daily maximum temperature and nighttime heat waves, detected with the daily minimum temperature. Daytime heat waves correspond to situations where cloud optical thickness is lower than the climatology and a large number of these situations are also associated with a lower aerosol load and a drier atmosphere. Nighttime heat waves correspond to a moister atmosphere compared to the climatology. In a large fraction of them, an increase in aerosol loading is also observed. This study, only based on observational data sets, highlights the subtle but different radiative balance at play in both types of events. radiation budget; observations; West Africa; heat wave
Caldwell, P. M.; Terai, C. R.; Hillman, B.; Keen, N. D.; Bogenschutz, P.; Lin, W.; Beydoun, H.; Taylor, M.; Bertagna, L.; Bradley, A. M.; Clevenger, T. C.; Donahue, A. S.; Eldred, C.; Foucar, J.; Golaz, J.-C.; Guba, O.; Jacob, R.; Johnson, J.; Krishna, J.; Liu, W.; Pressel, K.; Salinger, A. G.; Singh, B.; Steyer, A.; Ullrich, P.; Wu, D.; Yuan, X.; Shpund, J.; Ma, H.-Y.; Zender, C. S.Caldwell, P. M., C. R. Terai, B. Hillman, N. D. Keen, P. Bogenschutz, W. Lin, H. Beydoun, M. Taylor, L. Bertagna, A. M. Bradley, T. C. Clevenger, A. S. Donahue, C. Eldred, J. Foucar, J. Golaz, O. Guba, R. Jacob, J. Johnson, J. Krishna, W. Liu, K. Pressel, A. G. Salinger, B. Singh, A. Steyer, P. Ullrich, D. Wu, X. Yuan, J. Shpund, H. Ma, C. S. Zender, 2021: Convection-Permitting Simulations With the E3SM Global Atmosphere Model. Journal of Advances in Modeling Earth Systems, 13(11), e2021MS002544. doi: 10.1029/2021MS002544. This paper describes the first implementation of the Δx = 3.25 km version of the Energy Exascale Earth System Model (E3SM) global atmosphere model and its behavior in a 40-day prescribed-sea-surface-temperature simulation (January 20 through February 28, 2020). This simulation was performed as part of the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) Phase 2 model intercomparison. Effective resolution is found to be the horizontal dynamics grid resolution despite using a coarser grid for physical parameterizations. Despite this new model being in an immature and untuned state, moving to 3.25 km grid spacing solves several long-standing problems with the E3SM model. In particular, Amazon precipitation is much more realistic, the frequency of light and heavy precipitation is improved, agreement between the simulated and observed diurnal cycle of tropical precipitation is excellent, and the vertical structure of tropical convection and coastal stratocumulus look good. In addition, the new model is able to capture the frequency and structure of important weather events (e.g., tropical cyclones, extratropical cyclones including atmospheric rivers, and cold air outbreaks). Interestingly, this model does not get rid of the erroneous southern branch of the intertropical convergence zone nor the tendency for strongest convection to occur over the Maritime Continent rather than the West Pacific, both of which are classic climate model biases. Several other problems with the simulation are identified, underscoring the fact that this model is a work in progress. general circulation model; E3SM; cloud resolving model; convection permitting model; storm resolving model
Campbell, James R.; Dolinar, Erica K.; Lolli, Simone; Fochesatto, Gilberto J.; Gu, Yu; Lewis, Jasper R.; Marquis, Jared W.; McHardy, Theodore M.; Ryglicki, David R.; Welton, Ellsworth J.Campbell, J. R., E. K. Dolinar, S. Lolli, G. J. Fochesatto, Y. Gu, J. R. Lewis, J. W. Marquis, T. M. McHardy, D. R. Ryglicki, E. J. Welton, 2021: Cirrus Cloud Top-of-the-Atmosphere Net Daytime Forcing in the Alaskan Subarctic from Ground-Based MPLNET Monitoring. J. Appl. Meteor. Climatol., (In Press). doi: 10.1175/JAMC-D-20-0077.1. AbstractCirrus cloud daytime top-of-the-atmosphere radiative forcing (TOA CRF) is estimated for a two-year NASA Micro-Pulse Lidar Network (532 nm; MPLNET) dataset collected at Fairbanks, Alaska. Two-year averaged daytime TOA CRF is estimated at between -1.08 and 0.78 W·m-2 (-0.49 to 1.10 W·m-2 in 2017, and -1.67 to 0.47 W·m-2 in 2018). This subarctic study completes a now trilogy of MPLNET ground-based cloud forcing investigations, following midlatitude and tropical studies by Campbell et al. (2016; C16) at Greenbelt, Maryland and Lolli et al. (2017) at Singapore. C16 hypothesize a global meridional daytime TOA CRF gradient that begins positive at the equator (2.20 – 2.59 W·m-2 over land and -0.46 – 0.42 W·m-2 over ocean at Singapore), becomes neutral in the midlatitudes (0.03 – 0.27 W·m-2 over land in Maryland) and turns negative moving poleward. This study does not completely confirm C16, as values are not found as exclusively negative. Evidence in historical reanalysis data suggests that daytime cirrus forcing in and around the subarctic likely once was exclusively negative. Increasing tropopause heights, inducing higher and colder cirrus, have likely increased regional forcing over the last forty years. We hypothesize that subarctic inter-annual cloud variability is likely a considerable influence on global cirrus cloud forcing sensitivity, given the irregularity of polar versus midlatitude synoptic weather intrusions. This study and hypothesis lays basis for an extrapolation of these MPLNET experiments to satellite-based lidar cirrus cloud datasets.
Ceppi, Paulo; Fueglistaler, StephanCeppi, P., S. Fueglistaler, 2021: The El Niño–Southern Oscillation Pattern Effect. Geophysical Research Letters, 48(21), e2021GL095261. doi: 10.1029/2021GL095261. El Niño–Southern Oscillation (ENSO) variability is accompanied by out-of-phase anomalies in the top-of-atmosphere tropical radiation budget, with anomalous downward flux (i.e., net radiative heating) before El Niño and anomalous upward flux thereafter (and vice versa for La Niña). Here, we show that these radiative anomalies result mainly from a sea surface temperature (SST) “pattern effect,” mediated by changes in tropical-mean tropospheric stability. These stability changes are caused by SST anomalies migrating from climatologically cool to warm regions over the ENSO cycle. Our results are suggestive of a two-way coupling between SST variability and radiation, where ENSO-induced radiative changes may in turn feed back onto SST during ENSO. clouds; climate change; radiation budget; ENSO; climate feedbacks; climate variability
Ceppi, Paulo; Nowack, PeerCeppi, P., P. Nowack, 2021: Observational evidence that cloud feedback amplifies global warming. Proceedings of the National Academy of Sciences, 118(30). doi: 10.1073/pnas.2026290118. Global warming drives changes in Earth’s cloud cover, which, in turn, may amplify or dampen climate change. This “cloud feedback” is the single most important cause of uncertainty in Equilibrium Climate Sensitivity (ECS)—the equilibrium global warming following a doubling of atmospheric carbon dioxide. Using data from Earth observations and climate model simulations, we here develop a statistical learning analysis of how clouds respond to changes in the environment. We show that global cloud feedback is dominated by the sensitivity of clouds to surface temperature and tropospheric stability. Considering changes in just these two factors, we are able to constrain global cloud feedback to 0.43 ± 0.35 W⋅m−2⋅K−1 (90% confidence), implying a robustly amplifying effect of clouds on global warming and only a 0.5% chance of ECS below 2 K. We thus anticipate that our approach will enable tighter constraints on climate change projections, including its manifold socioeconomic and ecological impacts. clouds; climate change; climate feedbacks; climate modeling; climate sensitivity
Cerasoli, Sara; Yin, Jun; Porporato, AmilcareCerasoli, S., J. Yin, A. Porporato, 2021: Cloud cooling effects of afforestation and reforestation at midlatitudes. Proceedings of the National Academy of Sciences, 118(33). doi: 10.1073/pnas.2026241118. Because of the large carbon sequestration potential, reforestation and afforestation (R&A) are among the most prominent natural climate solutions. However, while their effectiveness is well established for wet tropics, it is often argued that R&A are less advantageous or even detrimental at higher latitudes, where the reduction of forest albedo (the amount of reflected solar radiation by a surface) tends to nullify or even overcome the carbon benefits. Here, we carefully analyze the situation for R&A at midlatitudes, where the warming effects due to vegetation albedo are regarded to be almost balanced by the cooling effects from an increased carbon storage. Using both satellite data and atmospheric boundary-layer models, we show that by including cloud–albedo effects due to land–atmosphere interactions, the R&A cooling at midlatitudes becomes prevalent. This points to a much greater potential of R&A for wet temperate regions than previously considered. cloud feedback; afforestation; carbon mitigation
Cesana, Grégory V.; Del Genio, Anthony D.Cesana, G. V., A. D. Del Genio, 2021: Observational constraint on cloud feedbacks suggests moderate climate sensitivity. Nature Climate Change, 11(3), 213-218. doi: 10.1038/s41558-020-00970-y. Global climate models predict warming in response to increasing GHG concentrations, partly due to decreased tropical low-level cloud cover and reflectance. We use satellite observations that discriminate stratocumulus from shallow cumulus clouds to separately evaluate their sensitivity to warming and constrain the tropical contribution to low-cloud feedback. We find an observationally inferred low-level cloud feedback two times smaller than a previous estimate. Shallow cumulus clouds are insensitive to warming, whereas global climate models exhibit a large positive cloud feedback in shallow cumulus regions. In contrast, stratocumulus clouds show sensitivity to warming and the tropical inversion layer strength, controlled by the tropical Pacific sea surface temperature gradient. Models fail to reproduce the historical sea surface temperature gradient trends and therefore changes in inversion strength, generating an overestimate of the positive stratocumulus cloud feedback. Continued weak east Pacific warming would therefore produce a weaker low-cloud feedback and imply a more moderate climate sensitivity (3.47 ± 0.33 K) than many models predict.
Chakraborty, T.; Lee, X.Chakraborty, T., X. Lee, 2021: Large Differences in Diffuse Solar Radiation Among Current-Generation Reanalysis and Satellite-Derived Products. J. Climate, -1(aop), 1-52. doi: 10.1175/JCLI-D-20-0979.1. AbstractThough the partitioning of shortwave radiation (K↓) at the surface into its diffuse (K↓,d) and direct beam (K↓,b) components is relevant for, among other things, the terrestrial energy and carbon budgets, there is a dearth of large-scale comparisons of this partitioning across reanalysis and satellite-derived products. Here we evaluate K↓, K↓,d, and K↓,b, as well as the diffuse fraction (kd) of solar radiation in four current-generation reanalysis (NOAA-CIRES-DOE, NCEP/NCAR, MERRA-2, ERA5) datasets and one satellite-derived product (CERES) using ≈1400 site years of observations. Although the systematic positive biases in K↓ is consistent with previous studies, the biases in gridded K↓,d and K↓,b vary in direction and magnitude, both annually and across seasons. The inter-model variability in cloud cover strongly explains the biases in both K↓,d and K↓,b. Over Europe and China, the long-term (10-year plus) trends in K↓,d in the gridded products are noticeably differ from corresponding observations and the grid-averaged 35-year trends show an order of magnitude variability. In the MERRA-2 reanalysis, which includes both clouds and assimilated aerosols, the reduction in both clouds and aerosols reinforce each other to establish brightening trends over Europe, while the effect of increasing aerosols overwhelm the effect of decreasing cloud cover over China. The inter-model variability in kd seen here (0.27 to 0.50 from CERES to MERRA-2) suggests substantial differences in shortwave parameterization schemes and their inputs in climate models and can contribute to inter-model variability in coupled simulations. Based on these results, we call for systematic evaluations of K↓,d and K↓,b in CMIP6 models.
Chang, Chiao-Wei; Chen, Wei-Ting; Chen, Yi-ChunChang, C., W. Chen, Y. Chen, 2021: Susceptibility of East Asian Marine Warm Clouds to Aerosols in Winter and Spring from Co-Located A-Train Satellite Observations. Remote Sensing, 13(24), 5179. doi: 10.3390/rs13245179. We constructed the A-Train co-located aerosol and marine warm cloud data from 2006 to 2010 winter and spring over East Asia and investigated the sensitivities of single-layer warm cloud properties to aerosols under different precipitation statuses and environmental regimes. The near-surface stability (NSS), modulated by cold air on top of a warm surface, and the estimated inversion strength (EIS) controlled by the subsidence are critical environmental parameters affecting the marine warm cloud structure over East Asia and, thus, the aerosols–cloud interactions. Based on our analysis, precipitating clouds revealed higher cloud susceptibility to aerosols as compared to non-precipitating clouds. The cloud liquid water path (LWP) increased with aerosols for precipitating clouds, yet decreased with aerosols for non-precipitating clouds, consistent with previous studies. For precipitating clouds, the cloud LWP and albedo increased more under higher NSS as unstable air promotes more moisture flux from the ocean. Under stronger EIS, the cloud albedo response to aerosols was lower than that under weaker EIS, indicating that stronger subsidence weakens the cloud susceptibility due to more entrainment drying. Our study suggests that the critical environmental factors governing the aerosol–cloud interactions may vary for different oceanic regions, depending on the thermodynamic conditions. aerosol–cloud interaction; cloud susceptibility; co-located data
Chao, Li-Wei; Dessler, Andrew E.Chao, L., A. E. Dessler, 2021: An Assessment of Climate Feedbacks in Observations and Climate Models Using Different Energy Balance Frameworks. J. Climate, 34(24), 9763-9773. doi: 10.1175/JCLI-D-21-0226.1. Abstract This study evaluates the performance of models from phase 5 and phase 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6) by comparing feedbacks in models with those inferred from observations. Overall, we find no systematic disagreements between the feedbacks in the model ensembles and feedbacks inferred from observations, although there is a wide range in the ability of individual models to reproduce the observations. In particular, 40 of 52 models have best estimates that fall within the uncertainty of the observed total feedback. We quantify two sources of uncertainty in the model ensembles: 1) the structural difference, due to the differences in model parameterizations, and 2) the unforced pattern effect, due to unforced variability, and find that both are important when comparing with an 18-yr observational dataset. We perform the comparison using two energy balance frameworks: the traditional energy balance framework, in which it is assumed that changes in energy balance are controlled by changes in global average surface temperatures, and an alternative framework that assumes the changes in energy balance are controlled by tropical atmospheric temperatures. We find that the alternative framework provides a more robust way of comparing the models with observations, with both smaller structural differences and smaller unforced pattern effect. However, when considering the relation of feedbacks in response to interannual variability and long-term warming, the traditional framework has advantages. There are no great differences between the CMIP5 and CMIP6 ensembles’ ability to reproduce the observed feedbacks.
Chen, Jiang; Zhu, Weining; Yu, QianChen, J., W. Zhu, Q. Yu, 2021: Estimating half-hourly solar radiation over the Continental United States using GOES-16 data with iterative random forest. Renewable Energy, 178, 916-929. doi: 10.1016/j.renene.2021.06.129. To reduce carbon emissions, using more solar energy is a feasible solution. Many meteorological-based models can estimate global downward solar radiation (DSR), but they are with limited applications due to the point-based estimation and low temporal resolution. Satellite remote sensing-based models can estimate DSR with better spatial coverage. However, most previous models are restricted to estimate clear-sky or monthly scale DSR at several sites, limiting the solar energy monitoring of nationwide scale. In this study, using high spatiotemporal resolution Geostationary Operational Environmental Satellites (GOES)-16 satellite data, an iterative random forest (RF) model was developed to estimate and map half-hourly DSR at 1-km spatial resolution over the Continental United States (CONUS). The results show that the iterative RF model performed better than multiple linear regression (MLR) and traditional RF models. The accuracy of estimating half-hourly DSR is that R2 = 0.95, root-mean-square-error (RMSE) = 66.92 W/m2, and mean-bias-error (MBE) = 0.06 W/m2. Half-hourly and daily DSR with spatial resolution 1-km over the CONUS were mapped. The GOES-16 estimated DSR showed the similar spatial patterns with the results from the Clouds and the Earth's Radiant Energy System (CERES) DSR product. This study demonstrated the potential of GOES-16 data for mapping DSR over the CONUS, and hence can be further used in solar energy related applications. Global solar radiation; Satellite remote sensing; Solar energy; Half-hourly; Iterative random forest
Chen, Shiliu; McColl, Kaighin A.; Berg, Alexis; Huang, YuefeiChen, S., K. A. McColl, A. Berg, Y. Huang, 2021: Surface Flux Equilibrium Estimates of Evapotranspiration at Large Spatial Scales. J. Hydrometeor., 22(4), 765-779. doi: 10.1175/JHM-D-20-0204.1. AbstractA recent theory proposes that inland continental regions are in a state of surface flux equilibrium (SFE), in which tight coupling between the land and atmosphere allow estimation of the Bowen ratio at daily to monthly time scales solely from atmospheric measurements, without calibration, even when the land surface strongly constrains the surface energy budget. However, since the theory has only been evaluated at quasi-point spatial scales using eddy covariance measurements with limited global coverage, it is unclear if it is applicable to the larger spatial scales relevant to studies of global climate. In this study, SFE estimates of the Bowen ratio are combined with satellite observations of surface net radiation to obtain large-scale estimates of latent heat flux λE. When evaluated against multiyear mean annual λE obtained from catchment water balance estimates from 221 catchments across the United States, the resulting error statistics are comparable to those in the catchment water balance estimates themselves. The theory is then used to diagnostically estimate λE using historical simulations from 26 CMIP6 models. The resulting SFE estimates are typically at least as accurate as the CMIP6 model’s simulated λE, when compared with catchment water balance estimates. Globally, there is broad spatial and temporal agreement between CMIP6 model SFE estimates and the CMIP6 model’s simulated λE, although SFE likely overestimates λE in some arid regions. We conclude that SFE applies reasonably at large spatial scales relevant to climate studies, and is broadly reproduced in climate models.
Chen, Yao-Sheng; Yamaguchi, Takanobu; Bogenschutz, Peter A.; Feingold, GrahamChen, Y., T. Yamaguchi, P. A. Bogenschutz, G. Feingold, 2021: Model Evaluation and Intercomparison of Marine Warm Low Cloud Fractions With Neural Network Ensembles. Journal of Advances in Modeling Earth Systems, 13(11), e2021MS002625. doi: 10.1029/2021MS002625. Low cloud fractions (LCFs) and meteorological factors (MFs) over an oceanic region containing multiple cloud regimes are examined for three data sets: one Energy Exascale Earth System Model (E3SM) simulation with the default 72-layer vertical grid (E3SM72), another one with 8-times vertical resolution via the Framework for Improvement by Vertical Enhancement (E3SM8), and one with MFs from ERA5 reanalysis and LCFs from the CERES SSF product (ERA5-SSF). Neural networks (NNs) are trained to capture the relationship between MFs and LCF and to select the best-performing MF subsets for predicting LCF. NN ensembles are used to (a) confirm the performance of selected MF subsets, (b) to serve as proxy models for each data set to predict LCFs for MFs from all data sets, and (c) to classify MFs into those in shared and uniquely occupied MF subspaces. Overall, E3SM72 and E3SM8 have large fractions of MFs in shared MF subspace, but less so near the Californian and Peruvian stratocumulus decks. E3SM8 and ERA5 have small fractions of MFs in shared MF subspace but greater than E3SM72 and ERA5, especially in the Southeast Pacific. The differences in LCFs between three pairs of data sets are decomposed into those associated with the differences in the LCF-MF relationship and those involving different MFs. Given the same MFs, LCFs produced by E3SM8 are greater than those produced by E3SM72 but are still different from those in ERA5-SSF. In general, the shift in MFs dominates the difference in the LCFs. E3SM; shallow clouds; machine learning; cloud controlling factors; high resolution modeling
Ciesielski, Paul E.; Johnson, Richard H.; Tang, Shuaiqi; Zhang, Yunyan; Xie, ShaochengCiesielski, P. E., R. H. Johnson, S. Tang, Y. Zhang, S. Xie, 2021: Comparison of Conventional and Constrained Variational Methods for Computing Large-Scale Budgets and Forcing Fields. Journal of Geophysical Research: Atmospheres, 126(16), e2021JD035183. doi: 10.1029/2021JD035183. Analyses of atmospheric heat and moisture budgets serve as an effective tool to study convective characteristics over a region and to provide large-scale forcing fields for various modeling applications. This paper examines two popular methods for computing large-scale atmospheric budgets: the conventional budget method (CBM) using objectively gridded analyses based primarily on radiosonde data and the constrained variational analysis (CVA) approach which supplements vertical profiles of atmospheric fields with measurements at the top of the atmosphere and at the surface to conserve mass, water, energy, and momentum. Successful budget computations are dependent on accurate sampling and analyses of the thermodynamic state of the atmosphere and the divergence field associated with convection and the large-scale circulation that influences it. Utilizing analyses generated from data taken during Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign conducted over the central Indian Ocean from October to December 2011, we evaluate the merits of these budget approaches and examine their limitations. While many of the shortcomings of the CBM, in particular effects of sampling errors in sounding data, are effectively minimized with CVA, accurate large-scale diagnostics in CVA are dependent on reliable background fields and rainfall constraints. For the DYNAMO analyses examined, the operational model fields used as the CVA background state provided wind fields that accurately resolved the vertical structure of convection in the vicinity of Gan Island. However, biases in the model thermodynamic fields were somewhat amplified in CVA resulting in a convective environment much weaker than observed. DYNAMO; forcing fields; large-scale atmospheric budgets; limitations; methodologies; strengths
Coelho, Caio A. S.; de Souza, Dayana C.; Kubota, Paulo Y.; Costa, Simone M. S.; Menezes, Layrson; Guimarães, Bruno S.; Figueroa, Silvio N.; Bonatti, José P.; Cavalcanti, Iracema F. A.; Sampaio, Gilvan; Klingaman, Nicholas P.; Baker, Jessica C. A.Coelho, C. A. S., D. C. de Souza, P. Y. Kubota, S. M. S. Costa, L. Menezes, B. S. Guimarães, S. N. Figueroa, J. Bonatti, . P., I. F. A. Cavalcanti, G. Sampaio, N. P. Klingaman, J. C. A. Baker, 2021: Evaluation of climate simulations produced with the Brazilian global atmospheric model version 1.2. Climate Dynamics, 56(3), 873-898. doi: 10.1007/s00382-020-05508-8. This paper presents an evaluation of climate simulations produced by the Brazilian Global Atmospheric Model version 1.2 (BAM-1.2) of the Center for Weather Forecast and Climate Studies (CPTEC). The model was run over the 1975–2017 period at two spatial resolutions, corresponding to ~ 180 and ~ 100 km, both with 42 vertical levels, following most of the Atmospheric Model Intercomparison Project (AMIP) protocol. In this protocol, observed sea surface temperatures (SSTs) are used as boundary conditions for the atmospheric model. Four ensemble members were run for each of the two resolutions. A series of diagnostics was computed for assessing the model’s ability to represent the top of the atmosphere (TOA) radiation, atmospheric temperature, circulation and precipitation climatological features. The representation of precipitation interannual variability, El Niño-Southern Oscillation (ENSO) precipitation teleconnections, the Madden and Julian Oscillation (MJO) and daily precipitation characteristics was also assessed. The model at both resolutions reproduced many observed temperature, atmospheric circulation and precipitation climatological features, despite several identified biases. The model atmosphere was found to be more transparent than the observations, leading to misrepresentation of cloud-radiation interactions. The net cloud radiative forcing, which produces a cooling effect on the global mean climate at the TOA, was well represented by the model. This was found to be due to the compensation between both weaker longwave cloud radiative forcing (LWCRF) and shortwave cloud radiative forcing (SWCRF) in the model compared to the observations. The model capability to represent inter-annual precipitation variability at both resolutions was found to be linked to the adequate representation of ENSO teleconnections. However, the model produced weaker than observed convective activity associated with the MJO. Light daily precipitation over the southeast of South America and other climatologically similar regions was diagnosed to be overestimated, and heavy daily precipitation underestimated by the model. Increasing spatial resolution helped to slightly reduce some of the diagnosed biases. The performed evaluation identified model aspects that need to be improved. These include the representation of polar continental surface and sea ice albedo, stratospheric ozone, low marine clouds, and daily precipitation features, which were found to be larger and last longer than the observed features.
Datseris, George; Stevens, BjornDatseris, G., B. Stevens, 2021: Earth’s Albedo and Its Symmetry. AGU Advances, 2(3), e2021AV000440. doi: 10.1029/2021AV000440. The properties of Earth's albedo and its symmetries are analyzed using twenty years of space-based Energy Balanced And Filled product of Clouds and the Earth's Radiant Energy System measurements. Despite surface asymmetries, top of the atmosphere temporally & hemispherically averaged reflected solar irradiance R appears symmetric over Northern/Southern hemispheres. This is confirmed with the use of surrogate time-series, which provides margins of 0.1±0.28Wm−2 for possible hemispheric differences supported by Clouds and Earth's Radiant System data. R time-series are further analyzed by decomposition into a seasonal (yearly and half yearly) cycle and residuals. Variability in the reflected solar irradiance is almost entirely (99%) due to the seasonal variations, mostly due to seasonal variations in insolation. The residuals of hemispherically averaged R are not only small, but also indistinguishable from noise, and thus not correlated across hemispheres. This makes yearly and sub-yearly timescales unlikely as the basis for a symmetry-establishing mechanism. The residuals however contain a global trend that is large, as compared to expected albedo feedbacks. It is also hemispherically symmetric, and thus indicates the possibility of a symmetry enforcing mechanism at longer timescales. To pinpoint precisely which parts of the Earth system establish the hemispheric symmetry, we create an energetically consistent cloud-albedo field from the data. We show that the surface albedo asymmetry is compensated by asymmetries between clouds over extra-tropical oceans, with southern hemispheric storm-tracks being 11% cloudier than their northern hemisphere counterparts. This again indicates that, assuming the albedo symmetry is not a result of chance, its mechanism likely operates on large temporal and spatial scales. CERES; albedo; energy balance; cloud albedo; hemispheric symmetry
de Freitas, Pedro Paulo; Paiva, Afonso de Moraes; Cirano, Mauro; Mill, Guilherme Nogueira; da Costa, Vladimir Santos; Gabioux, Mariela; França, Bruna Reis Leitede Freitas, P. P., A. d. M. Paiva, M. Cirano, G. N. Mill, V. S. da Costa, M. Gabioux, B. R. L. França, 2021: Coastal trapped waves propagation along the Southwestern Atlantic Continental Shelf. Continental Shelf Research, 226, 104496. doi: 10.1016/j.csr.2021.104496. This study investigates the propagation of coastal trapped waves (CTWs) along the Brazilian continental shelf between 34°S and 11°S using in situ data combined with the outputs from a high-resolution ocean simulation with HYCOM. The CTWs generation area covers a wide region ranging from the Patagonian shelf to the southern Brazilian shelf. The spectral analysis of coastal sea level series between 54°S and 10.5°S shows three bands of high energy associated with periods from 5 to 12 days, 15–22 days, and 25–40 days. The energy of the CTWs decreases along their propagation for all frequency bands, showing a drastic reduction north of 22°S, due to abrupt variations in the width and depth of the continental shelf between Tubarão Bight and Abrolhos Bank. Their phase speed propagation varies along the coast, being faster (>25 m/s) in the southernmost region (between 42°S and 41°S), reaching ~11 m/s north of 41°S, and reducing to ~3 m/s further north (equatorward of 24°S). The free Continental Shelf Wave theory supports the notion that the intense deceleration north of 24°S can be explained by the narrowing of the continental shelf. The stratification parameter indicates that the Brazilian continental shelf has a barotropic response to wind-generated disturbances. Air-sea interaction; Brazilian continental shelf; Coastal sea level; Continental Shelf Waves; Observing systems
Devi, N. S. M. P. LathaDevi, N. S. M. P. L., 2021: Recent Climatology and Environmental Impacts of Aerosols Observed from Satellite Data Over Yangtze River Delta Region. Research Trends and Challenges in Physical Science Vol. 4, 40-54. doi: 10.9734/bpi/rtcps/v4/12884D. The important elements of the climate system are aerosols and clouds, significantly affecting the radiation budget. They play an important role in modifying the hydrological cycle and chemistry of the atmosphere. The authors have analyzed and examined the optical and radiative effects of aerosols and clouds on the radiative forcing. This has been achieved through the investigation of aerosol optical depth (AOD), absorbing aerosol index (AAI), and vertically distributed aerosol types. The work reported in this paper demonstrates the spatiotemporal changes and climatology of aerosols and clouds over the urban agglomeration domain in East China, namely the Yangtze River Delta region during 2002-2020. The results revealed a strong spatiotemporal heterogeneity in AOD and AAI values over East China during the study period. The study also presents the impact of fire counts to understand the impact of forest fires and burning on the urban atmosphere. Further, we presented the vertical structure of aerosol distribution and their classification retrieved from the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) over the area during 2007-2020. Finally, the short-wave and long-wave cloud radiative forcing are investigated with the data obtained from the CERES (Clouds and the Earth’s Radiant Energy System) satellite over the domain. short- and long-wave radiation
Doelling, David R.; Cao, Changyong; Xiong, JDoelling, D. R., C. Cao, J. Xiong, 2021: GSICS recommends NOAA-20 VIIRS as reflective solar band (RSB) calibration reference. GSICS Quarterly Vol. 14 No. 4, 14(4), 2-4. doi: 10.25923/JMBT-D994.
Dong, Wenhao; Zhao, Ming; Ming, Yi; Ramaswamy, V.Dong, W., M. Zhao, Y. Ming, V. Ramaswamy, 2021: Representation of Tropical Mesoscale Convective Systems in a General Circulation Model: Climatology and Response to Global Warming. J. Climate, 34(14), 5657-5671. doi: 10.1175/JCLI-D-20-0535.1. AbstractThe characteristics of tropical mesoscale convective systems (MCSs) simulated with a finer-resolution (~50 km) version of the Geophysical Fluid Dynamics Laboratory (GFDL) AM4 model are evaluated by comparing with a comprehensive long-term observational dataset. It is shown that the model can capture the various aspects of MCSs reasonably well. The simulated spatial distribution of MCSs is broadly in agreement with the observations. This is also true for seasonality and interannual variability over different land and oceanic regions. The simulated MCSs are generally longer-lived, weaker, and larger than observed. Despite these biases, an event-scale analysis suggests that their duration, intensity, and size are strongly correlated. Specifically, longer-lived and stronger events tend to be bigger, which is consistent with the observations. The same model is used to investigate the response of tropical MCSs to global warming using time-slice simulations forced by prescribed sea surface temperatures and sea ice. There is an overall decrease in occurrence frequency, and the reduction over land is more prominent than over ocean.
Dong, Xiquan; Wu, Peng; Wang, Yuan; Xi, Baike; Huang, YiyiDong, X., P. Wu, Y. Wang, B. Xi, Y. Huang, 2021: New Observational Constraints on Warm Rain Processes and Their Climate Implications. Geophysical Research Letters, 48(6), e2020GL091836. doi: https://doi.org/10.1029/2020GL091836. Low stratiform clouds have profound impacts on the hydrological cycle and the Earth’s radiation budget. However, realistic simulation of low clouds in climate models presents a major challenge. Here we employ the newly retrieved cloud and drizzle microphysical properties to improve the autoconversion and accretion parameterizations in a microphysical scheme. We find that the new autoconversion (accretion) rate contributes 14% lower (greater) to total drizzle water content than the original scheme near the cloud top. Compared to satellite results, the simulated cloud liquid water path (LWP) and shortwave cloud radiative effect using the original scheme in a climate model agree well on global average but with large regional differences. Simulations using the updated scheme show a 7.3% decrease in the light rain frequency, and a 10% increase in LWP. The updated microphysics scheme alleviates the long-lasting problem in most climate models, that is “too frequent and too light precipitation.”
Espinoza, Jhan-Carlo; Arias, Paola A.; Moron, Vincent; Junquas, Clementine; Segura, Hans; Sierra-Pérez, Juan Pablo; Wongchuig, Sly; Condom, ThomasEspinoza, J., P. A. Arias, V. Moron, C. Junquas, H. Segura, J. P. Sierra-Pérez, S. Wongchuig, T. Condom, 2021: Recent Changes in the Atmospheric Circulation Patterns during the Dry-to-Wet Transition Season in South Tropical South America (1979–2020): Impacts on Precipitation and Fire Season. J. Climate, 34(22), 9025-9042. doi: 10.1175/JCLI-D-21-0303.1. Abstract We analyze the characteristics of atmospheric variations over tropical South America using the pattern recognition framework of weather typing or atmospheric circulation patterns (CPs). During 1979–2020, nine CPs are defined in the region, using a k-means algorithm based on daily unfiltered 850-hPa winds over 10°N–30°S, 90°–30°W. CPs are primarily interpreted as stages of the annual cycle of the low-level circulation. We identified three “winter” CPs (CP7, CP8, and CP9), three “summer” CPs (CP3, CP4, and CP5), and three “transitional” CPs (CP1, CP2, and CP6). Significant long-term changes are detected during the dry-to-wet transition season (July–October) over southern tropical South America (STSA). One of the wintertime patterns (CP9) increases from 20% in the 1980s to 35% in the last decade while the “transitional” CP2 decreases from 13% to 7%. CP9 is characterized by enhancement of the South American low-level jet and increasing atmospheric subsidence over STSA. CP2 is characterized by southerly cold-air incursions and anomalous convective activity over STSA. The years characterized by high frequency of CP9 and low frequency of CP2 during the dry-to-wet transition season are associated with a delayed South American monsoon onset and anomalous dry conditions over STSA. Consistently, a higher frequency of CP9 intensifies the fire season over STSA (1999–2020). Over the Brazilian states of Maranhão, Tocantins, Goiás, and São Paulo, the seasonal frequency of CP9 explains around 35%–44% of the interannual variations of fire counts.
Feldman, D. R.; Su, W.; Minnis, P.Feldman, D. R., W. Su, P. Minnis, 2021: Subdiurnal to Interannual Frequency Analysis of Observed and Modeled Reflected Shortwave Radiation From Earth. Geophysical Research Letters, 48(4), e2020GL089221. doi: https://doi.org/10.1029/2020GL089221. Estimates of global top-of-atmosphere radiation on monthly, seasonal, annual, and longer time-scales require estimates of the diurnal variability in both insolation and surface and atmospheric reflection. We compare Earth Polychromatic Imaging Camera (EPIC) and National Institute of Standards and Technology Advanced Radiometer (NISTAR) observations from the Deep Space Climate Observatory (DSCOVR) satellite with Clouds and Earth’s Radiant Energy System (CERES) hourly synoptic fluxes, which are diurnally filled through geostationary observations, and find that their power spectral density functions substantially agree, showing strong relative power at subdiurnal, diurnal, seasonal, and annual time-scales, and power growing from diurnal to seasonal time-scales. Frequency analysis of fluxes from several coupled model intercomparison project 5 model (CMIP5) and CMIP6 models shows that they distribute too much power over periods greater than 1 day but less than one year, indicating that a closer look is needed into how models achieve longer-term stability in reflected shortwave radiation. Model developers can consider using these datasets for time-varying energetic constraints, since tuning parameter choices will impact modeled planetary shortwave radiation across timescales ranging from subdiurnal to decadal. diurnal cycle; Albedo; DSCOVR; shortwave radiative energy budget
Fillmore, David; Rutan, David; Kato, Seiji; Rose, Fred; Caldwell, ThomasFillmore, D., D. Rutan, S. Kato, F. Rose, T. Caldwell, 2021: Evaluation of aerosol optical depths and clear-sky radiative fluxes of the CERES Edition 4.1 SYN1deg data product. Atmospheric Chemistry and Physics Discussions, 1-50. doi: 10.5194/acp-2021-283. Abstract. Aerosol optical depths (AOD) used for the Edition 4.1 Clouds and the Earth’s Radiant Energy System (CERES) Synoptic (SYN1deg) are evaluated. AODs are derived from Moderate Resolution Imaging Spectroradiometer (MODIS) observations and assimilated by an aerosol transport model (MATCH). As a consequence, clear-sky AODs closely match with those derived from MODIS instruments. AODs under all-sky conditions are larger than AODs under clear-sky conditions, which is supported by ground-based AERONET observations. When all-sky MATCH AODs are compared with Modern-Era Retrospective Analysis for Research and Applications (MERRA2) AODs, MATCH AODs are generally larger than MERRA2 AODS especially over convective regions (e.g. Amazon, central Africa, and eastern Asia). The difference is largely caused by MODIS AODs used for assimilation. Including AODs with larger retrieval uncertainty makes AODs over the convective regions larger. When AODs are used for clear-sky irradiance computations and computed downward shortwave irradiances are compared with ground- based observations, the computed instantaneous irradiances are 1 % to 2 % larger than observed irradiances. The comparison of top-of-atmosphere clear-sky irradiances with those derived from CERES observations suggests that AODs used for surface radiation observation sites are larger by 0.01 to 0.03, which is within the uncertainty of instantaneous MODIS AODs. However, the comparison with AERONET AOD suggests AODs used for computations over desert sites are 0.08 larger. The cause of positive biases of downward shortwave irradiance and AODs for the desert sites are unknown.
Freese, Lyssa M.; Cronin, Timothy W.Freese, L. M., T. W. Cronin, 2021: Antarctic Radiative and Temperature Responses to a Doubling of CO2. Geophysical Research Letters, 48(17), e2021GL093676. doi: 10.1029/2021GL093676. Greenhouse gases (GHGs), including carbon dioxide (), impact global and local outgoing longwave radiation (OLR). The Antarctic is known for its near-surface temperature inversion, where the addition of GHGs can lead to increased OLR during all but the winter months. These changes in OLR, however, are unable to explain modeled surface warming due to changes in GHGs across central Antarctica. Here we develop a simple explanation showing why adding always warms the surface, and allowing an estimation of the change in surface temperature due to a change in concentration based on the initial surface temperature. We develop a radiative-advective-turbulent single-column model based on observed temperatures for explicit comparisons between our estimations and model equilibrium behavior. We confirm that Antarctic surface temperatures warm as GHG concentrations increase, and find that this response is best explained through the surface greenhouse effect rather than that of the top of atmosphere (TOA). climate; temperature; radiation; Antarctic; GHG
Gasparini, Blaž; Rasch, Philip J.; Hartmann, Dennis L.; Wall, Casey J.; Dütsch, MarinaGasparini, B., P. J. Rasch, D. L. Hartmann, C. J. Wall, M. Dütsch, 2021: A Lagrangian Perspective on Tropical Anvil Cloud Lifecycle in Present and Future Climate. Journal of Geophysical Research: Atmospheres, 126(4), e2020JD033487. doi: https://doi.org/10.1029/2020JD033487. The evolution of tropical anvil clouds from their origin in deep convective cores to their slow decay determines the climatic effects of clouds in tropical convective regions. Despite the relevance of anvil clouds for climate and responses of clouds to global warming, processes dominating their evolution are not well understood. Currently available observational data reveal instantaneous snapshots of anvil cloud properties, but cannot provide a process-based perspective on anvil evolution. We therefore conduct simulations with the high resolution version of the exascale earth system model in which we track mesoscale convective systems over the tropical Western Pacific and compute trajectories that follow air parcels detrained from peaks of convective activity. With this approach we gain new insight into the anvil cloud evolution both in present day and future climate. Comparison with geostationary satellite data shows that the model is able to simulate maritime mesoscale convective systems reasonably well. Trajectory results indicate that anvil cloud lifetime is about 15 h with no significant change in a warmer climate. The anvil ice mixing ratio is larger in a warmer climate due to a larger source of ice by detrainment and larger depositional growth leading to a more negative net cloud radiative effect along detrained trajectories. However, the increases in sources are counteracted by increases in sinks of ice, particularly snow formation and sedimentation. Furthermore, we find that the mean anvil cloud feedback along trajectories is positive and consistent with results from more traditional cloud feedback calculation methods. cirrus clouds; cloud feedbacks; radiative effects; tropical convection; anvil clouds; convective life cycle
Ge, Jinming; Wang, Zhenquan; Wang, Chen; Yang, Xuan; Dong, Zixiang; Wang, MeihuaGe, J., Z. Wang, C. Wang, X. Yang, Z. Dong, M. Wang, 2021: Diurnal variations of global clouds observed from the CATS spaceborne lidar and their links to large-scale meteorological factors. Climate Dynamics. doi: 10.1007/s00382-021-05829-2. Diurnal cycle of cloud (DCC), referring to the diurnal variation of cloud macro- and micro-physical properties, thus largely determining the strength of net cloud radiative forcing (CRF), is a critical feature of clouds’ variation and is important for weather and climate evolutions. Nevertheless, neither the DCC vertical structures and their links to meteorology are well understood, nor the DCCs for different cloud type are accurately represented in current climate models. With unique orbit of the international space station, Cloud-Aerosol Transport System (CATS) lidar onboard the international space station (ISS) can sample cloud profiles at different local times and provide DCC vertical structures. In this study, we analyzed 2-year CATS data and found that the amplitude of diurnal cycle is significantly correlated with the mean frequency of occurrence. High clouds and oceanic low clouds have strong vertical development during nighttime, and continental low clouds tend to develop in daytime. These DCC features can impact the strength and the direction of CRF. Overall, large cloud cover and amplitude can amplify net cloud cooling effects, and high cloud nighttime (18:00 PM–06:00 AM) occurrence frequency can strengthen the cloud warming effects. To explain the DCC phenomenon, the instantaneous links between cloud vertical structure and lower-tropospheric stability (LTS), vertical velocity and cold point temperature (CPT) are discussed individually to show the evidence of their controls on cloud properties from tropics to midlatitude. Our results confirm that tropical water clouds and cirrus are more affected by LTS and CPT, respectively. Towards midlatitude from tropics, vertical velocity gradually plays a more important role in cloud development and dissipation. According to the diurnal cycles of these factors, temperature and static stability have the largest daily amplitude in the boundary layer of tropics and subtropics, which can explain the diurnal cycle of relative humidity and low clouds evolution, whereas vertical velocity has the largest daily amplitude in midlatitude, which is more related to the diurnal cycle of relative humidity and clouds in upper level of troposphere.
Gettelman, A.; Gagne, D. J.; Chen, C.-C.; Christensen, M. W.; Lebo, Z. J.; Morrison, H.; Gantos, G.Gettelman, A., D. J. Gagne, C. Chen, M. W. Christensen, Z. J. Lebo, H. Morrison, G. Gantos, 2021: Machine Learning the Warm Rain Process. Journal of Advances in Modeling Earth Systems, 13(2), e2020MS002268. doi: https://doi.org/10.1029/2020MS002268. Clouds are critical for weather and climate prediction. The multiple scales of cloud processes make simulation difficult. Often models and measurements are used to develop empirical relationships for large-scale models to be computationally efficient. Machine learning provides another potential tool to improve our empirical parameterizations of clouds. To explore these opportunities, we replace the warm rain formation process in a General Circulation Model (GCM) with a detailed treatment from a bin microphysical model that causes a 400% slowdown in the GCM. We analyze the changes in climate that result from the use of the bin microphysical calculation and find improvements in the rain onset and frequency of light rain compared to high resolution process models and observations. We also find a resulting change in the cloud feedback response of the model to warming, which will significantly impact the climate sensitivity. We then replace the bin microphysical model with several neural networks designed to emulate the autoconversion and accretion rates produced by the bin microphysical model. The neural networks are organized into two stages: the first stage identifies where tendencies will be nonzero (and the sign of the tendency), and the second stage predicts the magnitude of the autoconversion and accretion rates. We describe the risks of overfitting, extrapolation, and linearization by using perfect model experiments with and without the emulator. We can recover the solutions with the emulators in almost all respects, and get simulations that perform as the detailed model, but with the computational cost of the control simulation. clouds; microphysics; machine learning
Ghiz, Madison L.; Scott, Ryan C.; Vogelmann, Andrew M.; Lenaerts, Jan T. M.; Lazzara, Matthew; Lubin, DanGhiz, M. L., R. C. Scott, A. M. Vogelmann, J. T. M. Lenaerts, M. Lazzara, D. Lubin, 2021: Energetics of surface melt in West Antarctica. The Cryosphere, 15(7), 3459-3494. doi: 10.5194/tc-15-3459-2021. Abstract. We use reanalysis data and satellite remote sensing of cloud properties to examine how meteorological conditions alter the surface energy balance to cause surface melt that is detectable in satellite passive microwave imagery over West Antarctica. This analysis can detect each of the three primary mechanisms for inducing surface melt at a specific location: thermal blanketing involving sensible heat flux and/or longwave heating by optically thick cloud cover, all-wave radiative enhancement by optically thin cloud cover, and föhn winds. We examine case studies over Pine Island and Thwaites glaciers, which are of interest for ice shelf and ice sheet stability, and over Siple Dome, which is more readily accessible for field work. During January 2015 over Siple Dome we identified a melt event whose origin is an all-wave radiative enhancement by optically thin clouds. During December 2011 over Pine Island and Thwaites glaciers, we identified a melt event caused mainly by thermal blanketing from optically thick clouds. Over Siple Dome, those same 2011 synoptic conditions yielded a thermal-blanketing-driven melt event that was initiated by an impulse of sensible heat flux and then prolonged by cloud longwave heating. The December 2011 synoptic conditions also generated föhn winds at a location on the Ross Ice Shelf adjacent to the Transantarctic Mountains, and we analyze this case with additional support from automatic weather station data. In contrast, a late-summer thermal blanketing period over Pine Island and Thwaites glaciers during February 2013 showed surface melt initiated by cloud longwave heating and then prolonged by enhanced sensible heat flux. One limitation thus far with this type of analysis involves uncertainties in the cloud optical properties. Nevertheless, with improvements this type of analysis can enable quantitative prediction of atmospheric stress on the vulnerable Antarctic ice shelves in a steadily warming climate.
Ghosh, Sudipta; Riemer, Nicole; Giuliani, Graziano; Giorgi, Filippo; Ganguly, Dilip; Dey, SagnikGhosh, S., N. Riemer, G. Giuliani, F. Giorgi, D. Ganguly, S. Dey, 2021: Sensitivity of Carbonaceous Aerosol Properties to the Implementation of a Dynamic Aging Parameterization in the Regional Climate Model RegCM. Journal of Geophysical Research: Atmospheres, 126(17), e2020JD033613. doi: 10.1029/2020JD033613. Freshly emitted soot is hydrophobic, but condensation of secondary aerosols and coagulation with other particles modify its hygroscopic optical properties. This conversion is referred to as “aerosol aging.” Many climate models represent this aging process with a fixed aging time scale, whereas in reality, it is a dynamic process that depends on environmental conditions. Here, we implement a dynamic aging parameterization scheme in the regional climate model RegCM4 in place of the fixed aging timescale of 1.15 days (∼27.6 h) and examine its impact on the aerosol life cycle over the Indian subcontinent. The conversion from hydrophobic to hydrophilic aerosol is usually lower than 27.6 h over the entire landmass and lower than 10 h over the polluted Indo-Gangetic Basin (IGB), with seasonal variability. Due to the implementation of the dynamic aging scheme, the column burden and surface mass concentration of carbonaceous aerosols increase during the drier season (December–February) when washout is negligible. The burden is reduced during the wet season (June–September) due to a more efficient washout except over the IGB, where a reduction in precipitation as a result of radiative feedbacks increases the aerosol concentrations. Over the polluted IGB, surface dimming increases due to the dynamic aging scheme, with the top of the atmosphere forcing remaining mostly unchanged. As a result, atmospheric heating increases by at least 1.2 W/m2. Our results suggest that climate models should incorporate dynamic aging for a more realistic representation of aerosol simulations, especially in highly polluted regions. climate; black carbon; regional climate model; dynamic aging; feedback; India
Gibbins, Goodwin; Haigh, Joanna D.Gibbins, G., J. D. Haigh, 2021: Comments on “Global and Regional Entropy Production by Radiation Estimated from Satellite Observations”. J. Climate, 34(9), 3721-3728. doi: 10.1175/JCLI-D-20-0685.1. AbstractA recent paper by Kato and Rose reports a negative correlation between the annual mean entropy production rate of the climate and the absorption of solar radiation in the CERES SYN1deg dataset, using the simplifying assumption that the system is steady in time. It is shown here, however, that when the nonsteady interannual storage of entropy is accounted for, the dataset instead implies a positive correlation; that is, global entropy production rates increase with solar absorption. Furthermore, this increase is consistent with the response demonstrated by an energy balance model and a radiative–convective model. To motivate this updated analysis, a detailed discussion of the conceptual relationship between entropy production, entropy storage, and entropy flows is provided. The storage-corrected estimate for the mean global rate of entropy production in the CERES dataset from all irreversible transfer processes is 81.9 mW m−2 K−1 and from only nonradiative processes is 55.2 mW m−2 K−1 (observations from March 2000 to February 2018).
Girishkumar, M. S.; Joseph, Jofia; McPhaden, M. J.; Pattabhi Ram Rao, E.Girishkumar, M. S., J. Joseph, M. J. McPhaden, E. Pattabhi Ram Rao, 2021: Atmospheric Cold Pools and Their Influence on Sea Surface Temperature in the Bay of Bengal. Journal of Geophysical Research: Oceans, 126(9), e2021JC017297. doi: 10.1029/2021JC017297. Recent observations show that atmospheric cold pool (ACP) events are plentiful in the Bay of Bengal (BoB) during summer (May–September) and fall (October–November) and that these events can significantly modify local air-sea interaction processes on sub-daily time scales. In this study, we examine whether the magnitude of sea surface temperature (SST) drop associated with ACP events shows any diurnal variability during summer and fall. For this purpose, we use moored buoy data with a 10-min temporal resolution at 8°, 12°, and 15°N along 90°E and a one-dimensional mixed layer (ML) model. The analysis shows a reduction in SST (ΔSST) due to ACPs in the BoB during summer and fall, with a maximum magnitude of ΔSST during the afternoon (1200–1600 LST). However, the maximum magnitude of ΔSST during the afternoon is a factor of two higher during fall (∼−0.14°C) than summer (∼−0.07°C). Analysis based on observations and ACP sensitivity experiments indicates that the shallow daytime thermocline and associated thin surface ML is the primary factor regulating the day to night difference in ΔSST associated with ACPs. The presence of this shallow daytime thermocline and thin ML amplifies the effects on SST of net surface heat loss and entrainment of cold sub-surface water associated with enhanced ACP wind speeds. sea surface temperature; Bay of Bengal; air-sea interaction; mixed layer processes; atmospheric cold pool
Goode, P. R.; Pallé, E.; Shoumko, A.; Shoumko, S.; Montañes-Rodriguez, P.; Koonin, S. E.Goode, P. R., E. Pallé, A. Shoumko, S. Shoumko, P. Montañes-Rodriguez, S. E. Koonin, 2021: Earth's Albedo 1998–2017 as Measured From Earthshine. Geophysical Research Letters, 48(17), e2021GL094888. doi: 10.1029/2021GL094888. The reflectance of the Earth is a fundamental climate parameter that we measured from Big Bear Solar Observatory between 1998 and 2017 by observing the earthshine using modern photometric techniques to precisely determine daily, monthly, seasonal, yearly and decadal changes in terrestrial albedo from earthshine. We find the inter-annual fluctuations in albedo to be global, while the large variations in albedo within individual nights and seasonal wanderings tend to average out over each year. We measure a gradual, but climatologically significant 0.5 decline in the global albedo over the two decades of data. We found no correlation between the changes in the terrestrial albedo and measures of solar activity. The inter-annual pattern of earthshine fluctuations are in good agreement with those measured by CERES (data began in 2001) even though the satellite observations are sensitive to retroflected light while earthshine is sensitive to wide-angle reflectivity. The CERES decline is about twice that of earthshine. atmospheres; methods; observational; planetary systems; planets and satellites; spectroscopic techniques; stars: low mass
Grise, Kevin M.; Kelleher, Mitchell K.Grise, K. M., M. K. Kelleher, 2021: Midlatitude Cloud Radiative Effect Sensitivity to Cloud Controlling Factors in Observations and Models: Relationship with Southern Hemisphere Jet Shifts and Climate Sensitivity. J. Climate, 34(14), 5869-5886. doi: 10.1175/JCLI-D-20-0986.1. AbstractAn effective method to understand cloud processes and to assess the fidelity with which they are represented in climate models is the cloud controlling factor framework, in which cloud properties are linked with variations in large-scale dynamical and thermodynamical variables. This study examines how midlatitude cloud radiative effects (CRE) over oceans covary with four cloud controlling factors—midtropospheric vertical velocity, estimated inversion strength (EIS), near-surface temperature advection, and sea surface temperature (SST)—and assesses their representation in CMIP6 models with respect to observations and CMIP5 models. CMIP5 and CMIP6 models overestimate the sensitivity of midlatitude CRE to perturbations in vertical velocity and underestimate the sensitivity of midlatitude shortwave CRE to perturbations in EIS and temperature advection. The largest improvement in CMIP6 models is a reduced sensitivity of CRE to vertical velocity perturbations. As in CMIP5 models, many CMIP6 models simulate a shortwave cloud radiative warming effect associated with a poleward shift in the Southern Hemisphere (SH) midlatitude jet stream, an effect not present in observations. This bias arises because most models’ shortwave CRE are too sensitive to vertical velocity perturbations and not sensitive enough to EIS perturbations, and because most models overestimate the SST anomalies associated with SH jet shifts. The presence of this bias directly impacts the transient surface temperature response to increasing greenhouse gases over the Southern Ocean, but not the global-mean surface temperature. Instead, the models’ climate sensitivity is correlated with their shortwave CRE sensitivity to surface temperature advection perturbations near 40°S, with models with more realistic values of temperature advection sensitivity generally having higher climate sensitivity.
Gryspeerdt, Edward; McCoy, Daniel T.; Crosbie, Ewan; Moore, Richard H.; Nott, Graeme J.; Painemal, David; Small-Griswold, Jennifer; Sorooshian, Armin; Ziemba, LukeGryspeerdt, E., D. T. McCoy, E. Crosbie, R. H. Moore, G. J. Nott, D. Painemal, J. Small-Griswold, A. Sorooshian, L. Ziemba, 2021: The impact of sampling strategy on the cloud droplet number concentration estimated from satellite data. Atmospheric Measurement Techniques Discussions, 1-25. doi: 10.5194/amt-2021-371. Abstract. Cloud droplet number concentration (Nd) is of central importance to observation-based estimates of aerosol indirect effects, being used to quantify both the cloud sensitivity to aerosol and the base state of the cloud. However, the derivation of Nd from satellite data depends on a number of assumptions about the cloud and the accuracy of the retrievals of the cloud properties from which it is derived, making it prone to systematic biases. A number of sampling strategies have been proposed to address these biases by selecting the most accurate Nd retrievals in the satellite data. This work compares the impact of these strategies on the accuracy of the satellite retrieved Nd, using a selection of insitu measurements. In stratocumulus regions, the MODIS Nd retrieval is able to achieve a high precision (r2 of 0.5–0.8). This is lower in other cloud regimes, but can be increased by appropriate sampling choices. Although the Nd sampling can have significant effects on the Nd climatology, it produces only a 20 % variation in the implied radiative forcing from aerosol-cloud interactions, with the choice of aerosol proxy driving the overall uncertainty. The results are summarised into recommendations for using MODIS Nd products and appropriate sampling.
Guigma, Kiswendsida H.; Guichard, Françoise; Todd, Martin; Peyrille, Philippe; Wang, YiGuigma, K. H., F. Guichard, M. Todd, P. Peyrille, Y. Wang, 2021: Atmospheric tropical modes are important drivers of Sahelian springtime heatwaves. Climate Dynamics, 56(5), 1967-1987. doi: 10.1007/s00382-020-05569-9. Heatwaves pose a serious threat to human health worldwide but remain poorly documented over Africa. This study uses mainly the ERA5 dataset to investigate their large-scale drivers over the Sahel region during boreal spring, with a focus on the role of tropical modes of variability including the Madden–Julian Oscillation (MJO) and the equatorial Rossby and Kelvin waves. Heatwaves were defined from daily minimum and maximum temperatures using a methodology that retains only intraseasonal scale events of large spatial extent. The results show that tropical modes have a large influence on the occurrence of Sahelian heatwaves, and, to a lesser extent, on their intensity. Depending on their convective phase, they can either increase or inhibit heatwave occurrence, with the MJO being the most important of the investigated drivers. A certain sensitivity to the geographic location and the diurnal cycle is observed, with nighttime heatwaves more impacted by the modes over the eastern Sahel and daytime heatwaves more affected over the western Sahel. The examination of the physical mechanisms shows that the modulation is made possible through the perturbation of regional circulation. Tropical modes thus exert a control on moisture and the subsequent longwave radiation, as well as on the advection of hot air. A detailed case study of a major event, which took place in April 2003, further supports these findings. Given the potential predictability offered by tropical modes at the intraseasonal scale, this study has key implications for heatwave risk management in the Sahel.
Guo, Huan; Ming, Yi; Fan, Songmiao; Zhou, Linjiong; Harris, Lucas; Zhao, MingGuo, H., Y. Ming, S. Fan, L. Zhou, L. Harris, M. Zhao, 2021: Two-Moment Bulk Cloud Microphysics With Prognostic Precipitation in GFDL's Atmosphere Model AM4.0: Configuration and Performance. Journal of Advances in Modeling Earth Systems, 13(6), e2020MS002453. doi: 10.1029/2020MS002453. A two-moment Morrison-Gettelman bulk cloud microphysics with prognostic precipitation (MG2), together with a mineral dust and temperature-dependent ice nucleation scheme, have been implemented into the Geophysical Fluid Dynamics Laboratory's Atmosphere Model version 4.0 (AM4.0). We refer to this configuration as AM4-MG2. This paper describes the configuration of AM4-MG2, evaluates its performance, and compares it with AM4.0. It is shown that the global simulations with AM4-MG2 compare favorably with observations and reanalyses. The model skill scores are close to AM4.0. Compared to AM4.0, improvements in AM4-MG2 include (a) better coastal marine stratocumulus and seasonal cycles, (b) more realistic ice fraction, and (c) dominant accretion over autoconversion. Sensitivity tests indicate that nucleation and sedimentation schemes have significant impacts on cloud liquid and ice water fields, but higher horizontal resolution (about 50 km instead of 100 km) does not.
Guo, Zhun; Zhou, Tianjun; Wang, Minghuai; Yang, Ben; Wu, BoGuo, Z., T. Zhou, M. Wang, B. Yang, B. Wu, 2021: The role of Tibetan summer low clouds in the simulation of the East Asian summer monsoon rain belt. International Journal of Climatology, 1-13. doi: 10.1002/joc.7405. It has been challenging to simulate the East Asian summer monsoon (EASM) using general circulation models. By evaluating the cloud layers unified by binormals (CLUBB) model and its revised version in the version-5 Community Atmosphere Model, we find that EASM simulations benefit from improving the reproduction of low clouds over the Tibetan Plateau. When a cloud-top radiative cooling scheme (RAD) is coupled with CLUBB, it significantly improves the resulting EASM rain belt and western Pacific subtropical high (WPSH) simulations compared to the default simulations without RAD; in these default simulations, the low-level southwesterlies, WPSH ridge, and EASM rain belt are displaced northward. The moisture budget analyses indicate that the improvements in EASM simulations are mainly contributed to by the improved presentation of low-level stationary eddy meridional flow convergence over East Asia; this convergence shifts northward during the default model runs. Because the RAD scheme enables the model to better represent the subgrid radiation–turbulence interaction, the model produces stronger turbulent fluxes and lower clouds but reduces incoming solar radiation over the Tibetan Plateau. It thus shifts the Tibetan High southward, ultimately resulting in an improved simulation of the low-level southwesterlies. These improvements in CLUBB_RAD highlight the importance of improving the representation of low clouds when simulating EASM rainfall. Tibetan Plateau; low clouds; cloud-top radiative cooling scheme; EASM rain belt; low-level southwesterlies
Hakuba, M. Z.; Frederikse, T.; Landerer, F. W.Hakuba, M. Z., T. Frederikse, F. W. Landerer, 2021: Earth's Energy Imbalance From the Ocean Perspective (2005–2019). Geophysical Research Letters, 48(16), e2021GL093624. doi: 10.1029/2021GL093624. Earth's energy imbalance (EEI) represents the rate of global energy accumulation in response to radiative forcings and feedbacks. Ocean heat uptake (OHU) poses a vital constraint on EEI and its uncertainty. Considering recent geodetic observations, geophysical corrections, and new estimates of the ocean's expansion efficiency of heat, we translate steric sea-level change, the difference of total sea-level and ocean-mass change, into an OHU of 0.86 [0.62, 1.10, 5%–95%] Wm−2 for the period 2005–2019. Adding components of non-oceanic heat uptake, we obtain an EEI of 0.94 [0.70, 1.19] Wm−2, which is at the upper end of previous assessments, but agrees within uncertainty. Interannual geodetic OHU variability exhibits a higher correlation with top-of-the-atmosphere net radiative flux than hydrographic-only data, but has a three times larger standard deviation. The radiation fluxes and the geodetic approach suggest an increase in heat uptake since 2005, most markedly in recent years. ocean heat uptake; Earth's energy imbalance; Geodesy; sea level budget; thermal expansion
Ham, Seung-Hee; Kato, Seiji; Rose, Fred G.; Loeb, Norman G.; Xu, Kuan-Man; Thorsen, Tyler; Bosilovich, Michael G.; Sun-Mack, Sunny; Chen, Yan; Miller, Walter F.Ham, S., S. Kato, F. G. Rose, N. G. Loeb, K. Xu, T. Thorsen, M. G. Bosilovich, S. Sun-Mack, Y. Chen, W. F. Miller, 2021: Examining Cloud Macrophysical Changes over the Pacific for 2007–17 Using CALIPSO, CloudSat, and MODIS Observations. J. Appl. Meteor. Climatol., 60(8), 1105-1126. doi: 10.1175/JAMC-D-20-0226.1. AbstractCloud macrophysical changes over the Pacific Ocean from 2007 to 2017 are examined by combining CALIPSO and CloudSat (CALCS) active-sensor measurements, and these are compared with MODIS passive-sensor observations. Both CALCS and MODIS capture well-known features of cloud changes over the Pacific associated with meteorological conditions during El Niño–Southern Oscillation (ENSO) events. For example, midcloud (cloud tops at 3–10 km) and high cloud (cloud tops at 10–18 km) amounts increase with relative humidity (RH) anomalies. However, a better correlation is obtained between CALCS cloud volume and RH anomalies, confirming more accurate CALCS cloud boundaries than MODIS. Both CALCS and MODIS show that low cloud (cloud tops at 0–3 km) amounts increase with EIS and decrease with SST over the eastern Pacific, consistent with earlier studies. It is also further shown that the low cloud amounts do not increase with positive EIS anomalies if SST anomalies are positive. While similar features are found between CALCS and MODIS low cloud anomalies, differences also exist. First, relative to CALCS, MODIS shows stronger anticorrelation between low and mid/high cloud anomalies over the central and western Pacific, which is largely due to the limitation in detecting overlapping clouds from passive MODIS measurements. Second, relative to CALCS, MODIS shows smaller impacts of mid- and high clouds on the low troposphere (<3 km). The differences are due to the underestimation of MODIS cloud layer thicknesses of mid- and high clouds.
He, Haozhe; Kramer, Ryan J.; Soden, Brian J.He, H., R. J. Kramer, B. J. Soden, 2021: Evaluating Observational Constraints on Intermodel Spread in Cloud, Temperature, and Humidity Feedbacks. Geophysical Research Letters, 48(17), e2020GL092309. doi: 10.1029/2020GL092309. Uncertainty in climate feedbacks is the primary source of the spread in projected surface temperature responses to anthropogenic forcing. Cloud feedback persistently appears as the main source of disagreement in future projections while the combined lapse-rate plus water vapor (LR + WV) feedback is a smaller (30%), but non-trivial source of uncertainty in climate sensitivity. Here we attempt to observationally constrain the feedbacks in an effort to reduce their intermodel uncertainties. The observed interannual variation provides a useful constraint on the long-term cloud feedback, as evidenced by the consistency of global-mean values and regional contributions to the intermodel spread on both interannual and long-term timescales. However, interannual variability does not serve to constrain the long-term LR + WV feedback spread, which we find is dominated by the varying tropical relative humidity (RH) response to interhemispheric warming differences under clear-sky conditions and the RH-fixed LR feedback under all-sky conditions. cloud feedback; emergent constraint; intermodel spread; lapse-rate plus water vapor feedback
Henry, Matthew; Merlis, Timothy M.; Lutsko, Nicholas J.; Rose, Brian E. J.Henry, M., T. M. Merlis, N. J. Lutsko, B. E. J. Rose, 2021: Decomposing the Drivers of Polar Amplification with a Single-Column Model. J. Climate, 34(6), 2355-2365. doi: 10.1175/JCLI-D-20-0178.1. AbstractThe precise mechanisms driving Arctic amplification are still under debate. Previous attribution methods compute the vertically uniform temperature change required to balance the top-of-atmosphere energy imbalance caused by each forcing and feedback, with any departures from vertically uniform warming collected into the lapse-rate feedback. We propose an alternative attribution method using a single-column model that accounts for the forcing dependence of high-latitude lapse-rate changes. We examine this method in an idealized general circulation model (GCM), finding that, even though the column-integrated carbon dioxide (CO2) forcing and water vapor feedback are stronger in the tropics, they contribute to polar-amplified surface warming as they produce bottom-heavy warming in high latitudes. A separation of atmospheric temperature changes into local and remote contributors shows that, in the absence of polar surface forcing (e.g., sea ice retreat), changes in energy transport are primarily responsible for the polar-amplified pattern of warming. The addition of surface forcing substantially increases polar surface warming and reduces the contribution of atmospheric dry static energy transport to the warming. This physically based attribution method can be applied to comprehensive GCMs to provide a clearer view of the mechanisms behind Arctic amplification.
Hourdin, Frédéric; Williamson, Daniel; Rio, Catherine; Couvreux, Fleur; Roehrig, Romain; Villefranque, Najda; Musat, Ionela; Fairhead, Laurent; Diallo, F. Binta; Volodina, VictoriaHourdin, F., D. Williamson, C. Rio, F. Couvreux, R. Roehrig, N. Villefranque, I. Musat, L. Fairhead, F. B. Diallo, V. Volodina, 2021: Process-based climate model development harnessing machine learning: II. model calibration from single column to global. Journal of Advances in Modeling Earth Systems, (In Press). doi: https://doi.org/10.1029/2020MS002225. AbstractWe demonstrate a new approach for climate model tuning in a realistic situation. Our approach, the mathematical foundations and technical details of which are given in Part I, systematically uses a single-column configuration of a global atmospheric model on test cases for which reference large-eddy-simulations are available. The space of free parameters is sampled running the single-column model from which metrics are estimated in the full parameter space using emulators. The parameter space is then reduced by retaining only the values for which the emulated metrics match large eddy simulations within a given tolerance to error. The approach is applied to the 6A version of the LMDZ model which results from a long investment in the development of physics parameterizations and by-hand tuning. The boundary layer is revisited by increasing the vertical resolution and varying parameters that were kept fixed so far, which improves the representation of clouds at process scale. The approach allows us to automatically reach a tuning of this modified configuration as good as that of the 6A version. We show how this approach helps accelerate the introduction of new parameterizations. It allows us to maintain the physical foundations of the model and to ensure that the improvement of global metrics is obtained for a reasonable behavior at process level, reducing the risk of error compensations that may arise from over-fitting some climate metrics. That is, we get things right for the right reasons.
Huang, Han; Huang, Yi; Hu, YongyunHuang, H., Y. Huang, Y. Hu, 2021: Quantifying the energetic feedbacks in ENSO. Climate Dynamics, 56(1), 139-153. doi: 10.1007/s00382-020-05469-y. Energetic feedbacks play important roles during the El Niño-Southern Oscillation (ENSO). Here we conduct a thorough analysis of the radiative and non-radiative vertical fluxes and compare them to horizontal energy transport to provide a complete view of the energetics of ENSO. Our analyses affirm that cloud feedbacks are the most important radiative feedbacks, with cloud shortwave (SW) and longwave (LW) feedbacks dominating at the surface and in the atmosphere respectively. Oceanic energy transport dominates the oceanic heat content change in the developing phase and has significant effects on the sea surface temperature (SST) about 6 months earlier than vertical fluxes. Atmospheric horizontal energy transport is also important, acting to quickly remove the surplus of energy provided by the convergence of vertical energy fluxes in the atmosphere. The differential diabatic heating between the Central Pacific and the Warm Pool, induced by the latent heat release as well as LW radiation, strengthens the anomalous circulation and reinforces the Bjerknes positive feedback to strengthen the SST anomaly. This work reveals that the differential heating is more strongly correlated with the SST anomaly in the Central Pacific than the local SW negative feedback of clouds and supports the idea that the overall atmospheric effect is likely a positive feedback that acts to strengthen ENSO.
Huang, Xin; Ding, AijunHuang, X., A. Ding, 2021: Aerosol as a critical factor causing forecast biases of air temperature in global numerical weather prediction models. Science Bulletin. doi: 10.1016/j.scib.2021.05.009. Weather prediction is essential to the daily life of human beings. Current numerical weather prediction models such as the Global Forecast System (GFS) are still subject to substantial forecast biases and rarely consider the impact of atmospheric aerosol, despite the consensus that aerosol is one of the most important sources of uncertainty in the climate system. Here we demonstrate that atmospheric aerosol is one of the important drivers biasing daily temperature prediction. By comparing observations and the GFS prediction, we find that the monthly-averaged bias in the 24-h temperature forecast varies between ± 1.5 °C in regions influenced by atmospheric aerosol. The biases depend on the properties of aerosol, the underlying land surface, and aerosol–cloud interactions over oceans. It is also revealed that forecast errors are rapidly magnified over time in regions featuring high aerosol loadings. Our study provides direct “observational” evidence of aerosol’s impacts on daily weather forecast, and bridges the gaps between the weather forecast and climate science regarding the understanding of the impact of atmospheric aerosol. Aerosol–cloud interactions; Aerosol–radiation interactions; Atmospheric aerosol; Temperature forecast errors; Weather prediction
Huang, Yiyi; Ding, Qinghua; Dong, Xiquan; Xi, Baike; Baxter, IanHuang, Y., Q. Ding, X. Dong, B. Xi, I. Baxter, 2021: Summertime low clouds mediate the impact of the large-scale circulation on Arctic sea ice. Communications Earth & Environment, 2(1), 1-10. doi: 10.1038/s43247-021-00114-w. The rapid Arctic sea ice retreat in the early 21st century is believed to be driven by several dynamic and thermodynamic feedbacks, such as ice-albedo feedback and water vapor feedback. However, the role of clouds in these feedbacks remains unclear since the causality between clouds and these processes is complex. Here, we use NASA CERES satellite products and NCAR CESM model simulations to suggest that summertime low clouds have played an important role in driving sea ice melt by amplifying the adiabatic warming induced by a stronger anticyclonic circulation aloft. The upper-level high pressure regulates low clouds through stronger downward motion and increasing lower troposphere relative humidity. The increased low clouds favor more sea ice melt via emitting stronger longwave radiation. Then decreased surface albedo triggers a positive ice-albedo feedback, which further enhances sea ice melt. Considering the importance of summertime low clouds, accurate simulation of this process is a prerequisite for climate models to produce reliable future projections of Arctic sea ice.
Huang, Yiyi; Dong, Xiquan; Kay, Jennifer E.; Xi, Baike; McIlhattan, Elin A.Huang, Y., X. Dong, J. E. Kay, B. Xi, E. A. McIlhattan, 2021: The climate response to increased cloud liquid water over the Arctic in CESM1: a sensitivity study of Wegener–Bergeron–Findeisen process. Climate Dynamics. doi: 10.1007/s00382-021-05648-5. The surface radiative imbalance has large impacts on the long-term trends and year-to-year variability of Arctic sea ice. Clouds are believed to be a key factor in regulating this radiative imbalance, whose underlying processes and mechanisms, however, are not well understood. Compared with observations, the Community Earth System Model version 1 (CESM1) is known to underestimate Arctic cloud liquid water. Here, the following hypothesis is proposed and tested: this underestimation is caused by an overactive Wegener–Bergeron–Findeisen (WBF) process in model as too many supercooled liquid droplets are scavenged by ice crystals via deposition. In this study, the efficiency of the WBF process in CESM1 was reduced to investigate the Arctic climate response, and differentiate the responses induced by atmosphere–ocean–sea ice coupling and global warming. By weakening the WBF process, CESM1 simulated liquid cloud fractions increased, especially in winter and spring. The cloud response resulted in increased downwelling longwave flux and decreased shortwave flux at the surface. Arctic clouds and radiation in simulations with reduced WBF efficiency show a better agreement with satellite retrievals. In addition, both coupling and global warming amplify the cloud response to a less efficient WBF process, due to increased relative humidity and enhanced evaporation, respectively. As a response, the sea ice tends to melt over the North Atlantic Ocean, most likely caused by a positive feedback process between clouds, radiation and sea ice during non-summer months. These results improve our understanding of large-scale effects of the WBF process and the role of cloud liquid water in the Arctic climate system.
Itterly, Kyle; Taylor, Patrick; Roberts, J. BrentItterly, K., P. Taylor, J. B. Roberts, 2021: Satellite Perspectives of Sea Surface Temperature Diurnal Warming on Atmospheric Moistening and Radiative Heating During MJO. J. Climate, (In Press). doi: 10.1175/JCLI-D-20-0350.1.
Jadala, Nirmala Bai; Sridhar, Miriyala; Dutta, Gopa; Yousuf, Mohammed; Reddy, Y. K.Jadala, N. B., M. Sridhar, G. Dutta, M. Yousuf, Y. K. Reddy, 2021: Integrated water vapor during active and break spells of monsoon and its relationship with temperature, precipitation and precipitation efficiency over a tropical site. Geodesy and Geodynamics. doi: 10.1016/j.geog.2021.09.008. Global Positioning System (GPS) measurements of integrated water vapor (IWV) for two years (2014 and 2015) are presented in this paper. Variation of IWV during active and break spells of Indian summer monsoon has been studied for a tropical station Hyderabad (17.4° N, 78.46° E). The data is validated with ECMWF Re-Analysis (ERA) 91 level data. Relationships of IWV with other atmospheric variables like surface temperature, rain, and precipitation efficiency have been established through cross-correlation studies. A positive correlation coefficient is observed between IWV and surface temperature over two years. But the coefficient becomes negative when only summer monsoon months (June, July, August, and September) are considered. Rainfall during these months cools down the surface and could be the reason for this change in the correlation coefficient. Correlation studies between IWV- precipitation, IWV- precipitation efficiency (P.E), and precipitation-P.E show that coefficients are −0.05, −0.10 and 0.983 with 95% confidence level respectively, which proves that the efficacy of rain does not depend only on the level of water vapor. A proper dynamic mechanism is necessary to convert water vapor into the rain. The diurnal variations of IWV during active and break spells have been analyzed. The amplitudes of diurnal oscillation and its harmonics of individual spell do not show clear trends but the mean amplitudes of the break spells are approximately double than those of the active spells. The amplitudes of diurnal, semi-diurnal and ter-diurnal components during break spells are 1.08 kg/m2, 0.52 kg/m2 and 0.34 kg/m2 respectively. The corresponding amplitudes during active spells are 0.68 kg/m2, 0.41 kg/m2 and 0.23 kg/m2. Correlation coefficient; Diurnal oscillation; Precipitation efficiency
Jensen, Michael P.; Ghate, Virendra P.; Wang, Dié; Apoznanski, Diana K.; Bartholomew, Mary J.; Giangrande, Scott E.; Johnson, Karen L.; Thieman, Mandana M.Jensen, M. P., V. P. Ghate, D. Wang, D. K. Apoznanski, M. J. Bartholomew, S. E. Giangrande, K. L. Johnson, M. M. Thieman, 2021: Contrasting characteristics of open- and closed-cellular stratocumulus cloud in the eastern North Atlantic. Atmospheric Chemistry and Physics, 21(19), 14557-14571. doi: 10.5194/acp-21-14557-2021. Abstract. Extensive regions of marine boundary layer cloud impact the radiative balance through their significant shortwave albedo while having little impact on outgoing longwave radiation. Despite this importance, these cloud systems remain poorly represented in large-scale models due to difficulty in representing the processes that drive their life cycle and coverage. In particular, the mesoscale organization and cellular structure of marine boundary clouds have important implications for the subsequent cloud feedbacks. In this study, we use long-term (2013–2018) observations from the Atmospheric Radiation Measurement (ARM) Facility's Eastern North Atlantic (ENA) site on Graciosa Island, Azores, Portugal, to identify cloud cases with open- or closed-cellular organization. More than 500 h of each organization type are identified. The ARM observations are combined with reanalysis and satellite products to quantify the cloud, precipitation, aerosol, thermodynamic, and large-scale synoptic characteristics associated with these cloud types. Our analysis shows that both cloud organization populations occur during similar sea surface temperature conditions, but the open-cell cases are distinguished by stronger cold-air advection and large-scale subsidence compared to the closed-cell cases, consistent with their formation during cold-air outbreaks. We also find that the open-cell cases were associated with deeper boundary layers, stronger low-level winds, and higher rain rates compared to their closed-cell counterparts. Finally, raindrops with diameters larger than 1 mm were routinely recorded at the surface during both populations, with a higher number of large drops during the open-cellular cases. The similarities and differences noted herein provide important insights into the environmental and cloud characteristics during varying marine boundary layer cloud mesoscale organization and will be useful for the evaluation of model simulations for ENA marine clouds.
Jia, Aolin; Ma, Han; Liang, Shunlin; Wang, DongdongJia, A., H. Ma, S. Liang, D. Wang, 2021: Cloudy-sky land surface temperature from VIIRS and MODIS satellite data using a surface energy balance-based method. Remote Sensing of Environment, 263, 112566. doi: 10.1016/j.rse.2021.112566. Land surface temperature (LST) has been effectively retrieved from thermal infrared (TIR) satellite measurements under clear-sky conditions. However, TIR satellite data are often severely contaminated by clouds, which cause spatiotemporal discontinuities and low retrieval accuracy in the LST products. Several solutions have been proposed to fill the “gaps”; however, a majority of these possess constraints. For example, fusion methods with microwave data suffer from coarse spatial resolution and diverse land cover types while spatial-temporal interpolation methods neglect cloudy cooling effects. We developed a novel method to estimate cloudy-sky LST from polar-orbiting satellite data based on the surface energy balance (SEB) principle. First, the hypothetical clear-sky LST of missing or likely cloud-contaminated pixels was reconstructed by assimilating high-quality satellite retrievals into a time-evolving model built from reanalysis data using a Kalman filter data assimilation algorithm. Second, clear-sky LST was hypothetically corrected by accounting for cloud cooling based on SEB theory. The proposed method was applied to Visible Infrared Imaging Radiometer Suite (VIIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data, and further validated using ground measurements of fourteen sites from SURFRAD, BSRN, and AmeriFlux in 2013. VIIRS LST recovered from cloud gaps exhibited a root mean square error (RMSE) of 3.54 K, a bias of −0.36 K, R2 of 0.94, and sample size (N) of 2411, comparable to the accuracy of clear-sky LST products and cloudy-sky LST estimation from MODIS (RMSE of 3.69 K, bias of −0.45 K, R2 of 0.93, and N of 2398). Thus, the proposed method performs well across different sensors, seasons, and land cover types. The abnormal retrieval values caused by cloud contamination were also corrected in the proposed method. The overall accuracy was better than the downscaled cloudy-sky LST retrieved from passive microwave (PMW) observations and former SEB-based cloudy-sky LST estimation methods. Validation using time-series measurements showed that the all-sky LST time series, including both clear- and cloudy-sky retrievals, can capture realistic variability without sudden abruptions or discontinuities. RMSE values for the all-sky LST varied from 2.54 to 4.15 K at the fourteen sites. Spatially continuous LST maps over the Contiguous United States were compared with corresponding maps from PMW data in the winter and summer of 2018, exhibiting similar spatial patterns but with additional spatial details. Moreover, sensitivity analysis suggested that the reconstruction of clear-sky LST dominantly impacts the accuracy of cloudy-sky LST estimation. The proposed method can be potentially implemented in similar satellite sensors for global real-time production. Data assimilation; Land surface temperature; Cloudy-sky; Surface energy balance principle; VIIRS and MODIS
Jia, Hailing; Ma, Xiaoyan; Yu, Fangqun; Quaas, JohannesJia, H., X. Ma, F. Yu, J. Quaas, 2021: Significant underestimation of radiative forcing by aerosol–cloud interactions derived from satellite-based methods. Nature Communications, 12(1), 3649. doi: 10.1038/s41467-021-23888-1. Satellite-based estimates of radiative forcing by aerosol–cloud interactions (RFaci) are consistently smaller than those from global models, hampering accurate projections of future climate change. Here we show that the discrepancy can be substantially reduced by correcting sampling biases induced by inherent limitations of satellite measurements, which tend to artificially discard the clouds with high cloud fraction. Those missed clouds exert a stronger cooling effect, and are more sensitive to aerosol perturbations. By accounting for the sampling biases, the magnitude of RFaci (from −0.38 to −0.59 W m−2) increases by 55 % globally (133 % over land and 33 % over ocean). Notably, the RFaci further increases to −1.09 W m−2 when switching total aerosol optical depth (AOD) to fine-mode AOD that is a better proxy for CCN than AOD. In contrast to previous weak satellite-based RFaci, the improved one substantially increases (especially over land), resolving a major difference with models.
Jian, Bida; Li, Jiming; Wang, Guoyin; Zhao, Yuxin; Li, Yarong; Wang, Jing; Zhang, Min; Huang, JianpingJian, B., J. Li, G. Wang, Y. Zhao, Y. Li, J. Wang, M. Zhang, J. Huang, 2021: Evaluation of the CMIP6 marine subtropical stratocumulus cloud albedo and its controlling factors. Atmospheric Chemistry and Physics Discussions, 1-29. doi: https://doi.org/10.5194/acp-2020-1245. Abstract. The cloud albedo at the subtropical marine subtropical stratocumulus regions has a key role in regulating the regional energy budget. Based on 12 years of monthly data from multiple satellite datasets, the long-term, monthly and seasonal cycle averaged cloud albedo at five stratocumulus regions were investigated to inter-compare the atmosphere-only simulations of Phase 5 and 6 of the Coupled Model Inter-comparison Project (AMIP5 and AMIP6). Statistical results showed that the long-term regressed cloud albedos were underestimated in most AMIP6 models compared with the satellite-driven cloud albedos, and the AMIP6 models produced a similar spread of AMIP5 at all regions. The monthly mean and seasonal cycle of cloud albedo of AMIP6 ensemble mean showed better correlation with the satellite-driven observation than that of AMIP5 ensemble mean, however, fail to reproduce the values and amplitude in some regions. By employing the Modern-Era Retrospective Analysis for Research and Applications Version 2 data, this study estimated the relative contributions of different aerosols and meteorological factors on the marine stratocumulus cloud albedo under different cloud liquid water path (LWP) conditions. The multiple regression models can explain ~60 % of the changes in the cloud albedo. Under the monthly mean LWP ≤ 60 g m−2, dust and black carbon dominantly contributed to the changes in the cloud albedo, while sulfate aerosol contributed the most under the condition of 60 g m−2
Joseph, Jofia; Girishkumar, M. S.; McPhaden, M. J.; Rao, E. Pattabhi RamaJoseph, J., M. S. Girishkumar, M. J. McPhaden, E. P. R. Rao, 2021: Diurnal variability of atmospheric cold pool events and associated air-sea interactions in the Bay of Bengal during the summer monsoon. Climate Dynamics, 56(3), 837-853. doi: 10.1007/s00382-020-05506-w. Atmospheric cold pools generated from convective downdrafts can significantly modulate air-sea interaction processes, though the variability in cold pool events is not yet documented in the Bay of Bengal (BoB). In this study, the seasonal and diurnal variability of cold pool events (defined as a drop in air temperature greater than 1 °C within 30 min) in the BoB is examined using moored buoy measurements with 10-min temporal resolution at 8°N, 12°N, and 15°N along 90°E. The analysis shows that cold pools are plentiful and frequent during summer (May–September) and fall (October–November) compared to winter (December-February) and spring (March–April). Results also indicate a significant diurnal variability at 15°N and 12°N (but not at 8°N) during summer, with more frequent and intense cold pool events in the afternoon. Cold pools lead to an intensification of turbulent heat exchange between the ocean and atmosphere, with increased latent heat loss (~ 80 Wm−2) through both an increase in wind speed and reduction in air specific humidity and increased sensible heat loss (~ 40 Wm−2) due primarily to air temperature drops. There is also a significant diurnal variability in these air-sea exchanges during the summer, with a twofold enhancement in latent and sensible heat fluxes associated with afternoon vs nighttime cold pools events. Finally, we establish the connection between the enhancement of afternoon cold pool events and southeastward propagating synoptic-scale rainfall activity on diurnal time scales from the western BoB.
Joseph, Jofia; Girishkumar, M. S.; Varikoden, Hamza; Thangaprakash, V. P.; Shivaprasad, S.; Rama Rao, E. PattabhiJoseph, J., M. S. Girishkumar, H. Varikoden, V. P. Thangaprakash, S. Shivaprasad, E. P. Rama Rao, 2021: Observed sub-daily variability of latent and sensible heat fluxes in the Bay of Bengal during the summer. Climate Dynamics, 56(3), 917-934. doi: 10.1007/s00382-020-05512-y. The sub-daily variability of latent (LHF) and sensible heat flux (SHF) in the Bay of Bengal (BoB) during the summer (May–September) is examined using moored buoys data at 8° N (2008 and 2011), 12° N (2010, 2011, 2012, 2013, 2014, and 2015), and 15° N (2009, 2013, 2014, and 2015) along 90° E. In the weak wind regime ( 6 ms−1) with a range of ~ 13 Wm−2 at 8° N and ~ 17 Wm−2 at 12° N and 15° N. In the strong wind regime, SHF shows heat gain by the ocean with a maximum (minimum) value during the daytime (night), while it shows heat loss from the ocean in the weak wind regime with maximum (minimum) value during the night (daytime). The diurnal range of SHF does not show significant meridional variation in the strong (~ 3.5 Wm−2) and weak (~ 2 Wm−2) wind regime. The difference in sub-daily evolution of air-temperature, air-specific humidity, and wind speed determines distinct evolutions of LHF and SHF in different wind regimes, which appears to be driven by atmospheric boundary layer processes and eastward propagating land-sea breeze signals over the BoB. Finally, we also establish the relationship between sub-daily evolutions of turbulent heat fluxes in the different wind regimes with synoptic conditions associated with the active and break phases of the Indian summer monsoon.
Kang, Litai; Marchand, Roger; Smith, WilliamKang, L., R. Marchand, W. Smith, 2021: Evaluation of MODIS and Himawari-8 Low Clouds Retrievals Over the Southern Ocean With In Situ Measurements From the SOCRATES Campaign. Earth and Space Science, 8(3), e2020EA001397. doi: https://doi.org/10.1029/2020EA001397. Aircraft observations collected during the Southern Ocean Cloud Radiation Aerosol Transport Experimental Study in January-February of 2018 are used to evaluate cloud properties from three satellite-imager datasets: (1) the Moderate Resolution Imaging Spectroradiometer level 2 (collection 6.1) cloud product, (2) the CERES-MODIS Edition 4 cloud product, and (3) the NASA SatCORPS Himawari-8 cloud product. Overall the satellite retrievals compare well with the in situ observations, with little bias and modest to good correlation coefficients when considering all aircraft profiles for which there are coincident MODIS observations. The Himawari-8 product does, however, show a statistically significant mean bias of about 1.2 μm for effective radius (re) and 2.6 for optical depth (τ) when applied to a larger set of profiles with coincident Himawari-8 observations. The low overall mean-bias in the re retrievals is due in part to compensating errors between cases that are non- or lightly precipitating, with cases that have heavier precipitation. re is slightly biased high (by about 0.5–1.0 μm) for non- and lightly precipitating cases and biased low by about 3–4 μm for heavily precipitating cases when precipitation exits near cloud top. The bias in non- and lightly precipitating conditions is due to (at least in part) having assumed a drop size distribution in the retrieval that is too broad. These biases in the re ultimately propagate into the retrieved liquid water path and number concentration. clouds; MODIS; remote sensing; southern ocean; himawari-8; SOCRATES
Kato, Seiji; Loeb, Norman G.; Fasullo, John T.; Trenberth, Kevin E.; Lauritzen, Peter H.; Rose, Fred G.; Rutan, David A.; Satoh, MasakiKato, S., N. G. Loeb, J. T. Fasullo, K. E. Trenberth, P. H. Lauritzen, F. G. Rose, D. A. Rutan, M. Satoh, 2021: Regional Energy and Water Budget of a Precipitating Atmosphere over Ocean. J. Climate, 34(11), 4189-4205. doi: 10.1175/JCLI-D-20-0175.1. AbstractEffects of water mass imbalance and hydrometeor transport on the enthalpy flux and water phase on diabatic heating rate in computing the regional energy and water budget of the atmosphere over ocean are investigated. Equations of energy and water budget of the atmospheric column that explicitly consider the velocity of liquid and ice cloud particles, and rain and snow are formulated by separating water variables from dry air. Differences of energy budget equations formulated in this study from those used in earlier studies are that 1) diabatic heating rate depends on water phase, 2) diabatic heating due to net condensation of nonprecipitating hydrometeors is included, and 3) hydrometeors can be advected with a different velocity from the dry-air velocity. Convergence of water vapor associated with phase change and horizontal transport of hydrometeors is to increase diabatic heating in the atmospheric column where hydrometeors are formed and exported and to reduce energy where hydrometeors are imported and evaporated. The process can improve the regional energy and water mass balance when energy data products are integrated. Effects of enthalpy transport associated with water mass transport through the surface are cooling to the atmosphere and warming to the ocean when the enthalpy is averaged over the global ocean. There is no net effect to the atmosphere and ocean columns combined. While precipitation phase changes the regional diabatic heating rate up to 15 W m−2, the dependence of the global mean value on the temperature threshold of melting snow to form rain is less than 1 W m−2.
Kato, Seiji; Rose, Fred G.Kato, S., F. G. Rose, 2021: Reply to “Comments on ‘Global and Regional Entropy Production by Radiation Estimated from Satellite Observations’”. J. Climate, 34(9), 3729-3731. doi: 10.1175/JCLI-D-20-0950.1. AbstractThis reply addresses a comment on the study by Kato and Rose (herein referred to as KR2020). The comment raises four points of criticism. These are 1) on notations used, 2) on a steady-state assumption made, 3) on the result of entropy production change with Earth’s albedo, and 4) disputing the statement that a simple energy balance model cannot produce absorption temperature change with Earth’s albedo. We concur on points 2 and 3 raised by the comment and recognize the significance of entropy storage due to ocean heating in the analysis of how entropy production changes with the shortwave absorptivity of Earth. Once entropy storage is considered, the results of KR2020 indicate that the increase of entropy production rate by irreversible processes, including by radiative processes, is smaller than the increase of entropy storage when absorptivity is increased. This is a manifestation of the primary contribution of positive top-of-atmosphere net irradiances (i.e., energy input to Earth) to heating the ocean and is consistent with an energy budget perspective. Once entropy storage is separated, the entropy production by irreversible processes increases with the shortwave absorptivity.
Kato, Seiji; Rose, Fred G.; Chang, Fu-Lung; Painemal, David; Smith, William L.Kato, S., F. G. Rose, F. Chang, D. Painemal, W. L. Smith, 2021: Evaluation of Regional Surface Energy Budget Over Ocean Derived From Satellites. Frontiers in Marine Science, 8, 1264. doi: 10.3389/fmars.2021.688299. The energy balance equation of an atmospheric column indicates that two approaches are possible to compute regional net surface energy flux. The first approach is to use the sum of surface energy flux components Fnet,c and the second approach is to use net top-of-atmosphere (TOA) irradiance and horizontal energy transport by the atmosphere Fnet,t. When regional net energy flux is averaged over the global ocean, Fnet,c and Fnet,t are, respectively, 16 and 2 Wm–2, both larger than the ocean heating rate derived from ocean temperature measurements. The difference is larger than the estimated uncertainty of Fnet,t of 11 Wm–2. Larger regional differences between Fnet,c and Fnet,t exist over tropical ocean. The seasonal variability of energy flux components averaged between 45°N and 45°S ocean reveals that the surface provides net energy to the atmosphere from May to July. These two examples demonstrates that the energy balance can be used to assess the quality of energy flux data products.
Kawai, Hideaki; Koshiro, Tsuyoshi; Yukimoto, SeijiKawai, H., T. Koshiro, S. Yukimoto, 2021: Relationship between shortwave radiation bias over the Southern Ocean and the double-intertropical convergence zone problem in MRI-ESM2. Atmospheric Science Letters, 22(12), e1064. doi: 10.1002/asl.1064. The relationship between improvements in the radiation bias over the Southern Ocean and the alleviation of the double-intertropical convergence zone (ITCZ) problem in the actual updates of our climate models is investigated. The radiation bias in MRI-CGCM3 that was used for CMIP5 simulations, particularly over the Southern Ocean, is significantly reduced in MRI-ESM2 that is used for CMIP6 simulations. Each modification that contributed to the reduction of the radiation bias was progressively reverted to the corresponding older treatment in order to examine their individual impacts on the ITCZ representation. Results show the double-ITCZ problem worsens almost monotonically when the excessive shortwave insolation over the Southern Ocean increases. The contribution of the atmosphere is about one third of the impact on the total northward energy transport and the corresponding response of the Hadley cell is related to the change in the double-ITCZ. However, our results also imply that the ITCZ bias cannot be completely resolved by the improvements of radiative flux alone and that there are other causes of the problem. cloud; ITCZ; climate model; Southern Ocean
Kim, Rachel; Tremblay, L. Bruno; Brunette, Charles; Newton, RobertKim, R., L. B. Tremblay, C. Brunette, R. Newton, 2021: A Regional Seasonal Forecast Model of Arctic Minimum Sea Ice Extent: Reflected Solar Radiation versus Late Winter Coastal Divergence. J. Climate, 34(15), 6097-6113. doi: 10.1175/JCLI-D-20-0846.1. AbstractThinning sea ice cover in the Arctic is associated with larger interannual variability in the minimum sea ice extent (SIE). The current generation of forced or fully coupled models, however, has difficulty predicting SIE anomalies from the long-term trend, highlighting the need to better identify the mechanisms involved in the seasonal evolution of sea ice cover. One such mechanism is coastal divergence (CD), a proxy for ice thickness anomalies based on late winter ice motion, quantified using Lagrangian ice tracking. CD gains predictive skill through the positive feedback of surface albedo anomalies, mirrored in reflected solar radiation (RSR), during melt season. Exploring the dynamic and thermodynamic contributions to minimum SIE predictability, RSR, initial SIE (iSIE), and CD are compared as predictors using a regional seasonal sea ice forecast model for 1 July, 1 June, and 1 May forecast dates for all Arctic peripheral seas. The predictive skill of June RSR anomalies mainly originates from open water fraction at the surface; that is, June iSIE and June RSR have equal predictive skill for most seas. The finding is supported by the surprising positive correlation found between June melt pond fraction (MPF) and June RSR in all peripheral seas: MPF anomalies indicate the presence of ice or open water, which is key to creating minimum SIE anomalies. This contradicts models that show correlation between melt onset, MPF, and the minimum SIE. A hindcast model shows that for a 1 May forecast, CD anomalies have better predictive skill than RSR anomalies for most peripheral seas.
Koppa, Akash; Alam, Sarfaraz; Miralles, Diego G.; Gebremichael, MekonnenKoppa, A., S. Alam, D. G. Miralles, M. Gebremichael, 2021: Budyko-Based Long-Term Water and Energy Balance Closure in Global Watersheds From Earth Observations. Water Resources Research, 57(5), e2020WR028658. doi: https://doi.org/10.1029/2020WR028658. Earth observations offer potential pathways for accurately closing the water and energy balance of watersheds, a fundamental challenge in hydrology. However, previous attempts based on purely satellite-based estimates have focused on closing the water and energy balances separately. They are hindered by the lack of estimates of key components, such as runoff. Here, we posit a novel approach based on Budyko’s water and energy balance constraints. The approach is applied to quantify the degree of long-term closure at the watershed scale, as well as its associated uncertainties, using an ensemble of global satellite data sets. We find large spatial variability across aridity, elevation, and other environmental gradients. Specifically, we find a positive correlation between elevation and closure uncertainty, as derived from the Budyko approach. In mountainous watersheds the uncertainty in closure is 3.9 ± 0.7 (dimensionless). Our results show that uncertainties in terrestrial evaporation contribute twice as much as precipitation uncertainties to errors in the closure of water and energy balance. Moreover, our results highlight the need for improving satellite-based precipitation and evaporation data in humid temperate forests, where the closure error in the Budyko space is as high as 1.1 ± 0.3, compared to only 0.2 ± 0.03 in tropical forests. Comparing the results with land surface model-based data sets driven by in situ precipitation, we find that Earth observation-based data sets perform better in regions where precipitation gauges are sparse. These findings have implications for improving the understanding of global hydrology and regional water management and can guide the development of satellite remote sensing-based data sets and Earth system models. precipitation; remote sensing; water balance; evapotranspiration; Budyko hypothesis; energy Balance
Kottayil, Ajil; Xavier, Anu; Xavier, Prince; Koovekkallu, Prajwal; Mohanakumar, KesavapillaiKottayil, A., A. Xavier, P. Xavier, P. Koovekkallu, K. Mohanakumar, 2021: Evolution of large-scale factors influencing extreme rainfall over south western coast of India. International Journal of Climatology, 1-15. doi: 10.1002/joc.7455. The life cycle and the large-scale factors driving extreme heavy rainfall events over the south west coast of India are studied. The extreme rainfall events are linked to the development of monsoon depressions and the associated large-scale dynamics. Strengthening of these parameters intensifies the monsoon low-level circulation over the Arabian Sea and the west coast via steepened meridional pressure gradient. The intensification of the low-level jet stream speed and its extension in the vertical causes an increase in the humidity flux in the lower and midtroposphere. The consequent ascending motion is from the midtroposphere to the upper troposphere, resulting in the formation of deep convective cloud clusters over the west coast and eastern parts of the Arabian Sea. This results in the incidence of extreme heavy rainfall over the south west coast of India. It is observed that during days of extreme rainfall, the direction of wind in the lower troposphere tends to be almost perpendicular to the Western Ghats favouring a strong orographic lift. The extreme rainfall events over the south west coast do not necessarily occur during the active cycle of monsoon intraseasonal oscillation, but are linked to the north westwards propagating monsoon depressions. We show that the signatures of extreme rainfall can be observed in several meteorological variables developing over different parts of the monsoon region. A synergistic analysis of these variables may help in the accurate and timely prediction of these events. monsoon; extreme rainfall; low-level jet; moisture flux; Western Ghats
Kramer, Ryan J.; He, Haozhe; Soden, Brian J.; Oreopoulos, Lazaros; Myhre, Gunnar; Forster, Piers M.; Smith, Christopher J.Kramer, R. J., H. He, B. J. Soden, L. Oreopoulos, G. Myhre, P. M. Forster, C. J. Smith, 2021: Observational evidence of increasing global radiative forcing. Geophysical Research Letters, n/a(n/a), e2020GL091585. doi: https://doi.org/10.1029/2020GL091585. Changes in atmospheric composition, such as increasing greenhouse gases, cause an initial radiative imbalance to the climate system, quantified as the instantaneous radiative forcing. This fundamental metric has not been directly observed globally and previous estimates have come from models. In part, this is because current space-based instruments cannot distinguish the instantaneous radiative forcing from the climate’s radiative response. We apply radiative kernels to satellite observations to disentangle these components and find all-sky instantaneous radiative forcing has increased 0.53±0.11 W/m2 from 2003 through 2018, accounting for positive trends in the total planetary radiative imbalance. This increase has been due to a combination of rising concentrations of well-mixed greenhouse gases and recent reductions in aerosol emissions. These results highlight distinct fingerprints of anthropogenic activity in Earth’s changing energy budget, which we find observations can detect within 4 years. aerosols; radiative forcing; greenhouse gases; radiative kernels
Lang, Simon T. K.; Dawson, Andrew; Diamantakis, Michail; Dueben, Peter; Hatfield, Samuel; Leutbecher, Martin; Palmer, Tim; Prates, Fernando; Roberts, Christopher D.; Sandu, Irina; Wedi, NilsLang, S. T. K., A. Dawson, M. Diamantakis, P. Dueben, S. Hatfield, M. Leutbecher, T. Palmer, F. Prates, C. D. Roberts, I. Sandu, N. Wedi, 2021: More accuracy with less precision. Quarterly Journal of the Royal Meteorological Society, 147(741), 4358-4370. doi: 10.1002/qj.4181. Reducing the numerical precision of the forecast model of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) from double to single precision results in significant computational savings without negatively affecting forecast accuracy. The computational savings allow to increase the vertical resolution of the operational ensemble forecasts from 91 to 137 levels earlier than anticipated and before the next upgrade of ECMWF's high-performance computing facility. This upgrade to 137 levels harmonises the vertical resolution of the medium-range deterministic forecasts and the medium-range and extended-range ensemble forecasts. Increasing the vertical resolution of the ensemble forecasts substantially improves forecast skill for all lead times as well as the mean of the model climate. ECMWF's ensemble and deterministic forecasts will run operationally at single precision from IFS model cycle 47R2 onwards. ensemble forecasting; reduced precision
Lang, Simon T. K.; Lock, Sarah-Jane; Leutbecher, Martin; Bechtold, Peter; Forbes, Richard M.Lang, S. T. K., S. Lock, M. Leutbecher, P. Bechtold, R. M. Forbes, 2021: Revision of the Stochastically Perturbed Parametrisations model uncertainty scheme in the Integrated Forecasting System. Quarterly Journal of the Royal Meteorological Society, 147(735), 1364-1381. doi: https://doi.org/10.1002/qj.3978. The Stochastically Perturbed Parametrisations scheme (SPP) represents model uncertainty in numerical weather prediction by introducing stochastic perturbations into the physical parametrisation schemes. The perturbations are constructed in such a way that the internal consistency of the physical parametrisation schemes is preserved. We developed a revised version of SPP for the Integrated Forecasting System of the European Centre for Medium-Range Weather Forecasts (ECMWF). The revised version introduces perturbations to additional quantities and modifies the probability distributions sampled by the scheme. Medium-range ensemble forecasts with the revised SPP are considerably more skilful than ensemble forecasts with the original implementation of SPP. The revised version of SPP is similar, in terms of forecast skill, to the Stochastically Perturbed Parametrisation Tendency scheme (SPPT), which is currently used to represent model uncertainty in the operational ECMWF ensemble forecasts. stochastic physics; ensemble forecasting; ensemble perturbation methods; SPP; SPPT
Lee, Hsiang-He; Bogenschutz, Peter; Yamaguchi, TakanobuLee, H., P. Bogenschutz, T. Yamaguchi, 2021: The Implementation of Framework for Improvement by Vertical Enhancement Into Energy Exascale Earth System Model. Journal of Advances in Modeling Earth Systems, 13(6), e2020MS002240. doi: 10.1029/2020MS002240. The low cloud bias in global climate models (GCMs) remains an unsolved problem. Coarse vertical resolution in GCMs has been suggested to be a significant cause of low cloud bias because planetary boundary layer parameterizations cannot resolve sharp temperature and moisture gradients often found at the top of subtropical stratocumulus layers. This work aims to ameliorate the low cloud problem by implementing a new computational method, the Framework for Improvement by Vertical Enhancement (FIVE), into the Energy Exascale Earth System Model (E3SM). Three physics schemes representing microphysics, radiation, and turbulence as well as vertical advection are interfaced to vertically enhanced physics (VEP), which allows for these processes to be computed on a higher vertical resolution grid compared to the rest of the E3SM model. We demonstrate the better representation of subtropical boundary layer clouds with FIVE while limiting additional computational cost from the increased number of levels. When the vertical resolution approaches the large eddy simulation-like vertical resolution in VEP, the climatological low cloud amount shows a significant increase of more than 30% in the southeastern Pacific Ocean. Using FIVE to improve the representation of low-level clouds does not come with any negative side effects associated with the simulation of mid- and high-level cloud and precipitation, that can occur when running the full model at higher vertical resolution. marine boundary layer; E3SM; vertical resolution; stratocumulus cloud; FIVE; low-level cloud
Lee, Jiwoo; Planton, Yann Y.; Gleckler, Peter J.; Sperber, Kenneth R.; Guilyardi, Eric; Wittenberg, Andrew T.; McPhaden, Michael J.; Pallotta, GiulianaLee, J., Y. Y. Planton, P. J. Gleckler, K. R. Sperber, E. Guilyardi, A. T. Wittenberg, M. J. McPhaden, G. Pallotta, 2021: Robust Evaluation of ENSO in Climate Models: How Many Ensemble Members Are Needed?. Geophysical Research Letters, 48(20), e2021GL095041. doi: 10.1029/2021GL095041. Large ensembles of model simulations require considerable resources, and thus defining an appropriate ensemble size for a particular application is an important experimental design criterion. We estimate the ensemble size (N) needed to assess a model’s ability to capture observed El Niño-Southern Oscillation (ENSO) behavior by utilizing the recently developed International CLIVAR ENSO Metrics Package. Using the larger ensembles available from CMIP6 and the US CLIVAR Large Ensemble Working Group, we find that larger ensembles are needed to robustly capture baseline ENSO characteristics (N > 50) and physical processes (N > 50) than the background climatology (N ≥ 12) and remote ENSO teleconnections (N ≥ 6). While these results vary somewhat across metrics and models, our study quantifies how larger ensembles are required to robustly evaluate simulated ENSO behavior, thereby providing some guidance for the design of model ensembles. ENSO; CMIP6; large ensemble; CLIVAR ENSO metrics; Monte-Carlo sampling; PCMDI metrics package (PMP)
Li, Jianduo; Miao, Chiyuan; Wei, Wei; Zhang, Guo; Hua, Lijuan; Chen, Yueli; Wang, XiaoxiaoLi, J., C. Miao, W. Wei, G. Zhang, L. Hua, Y. Chen, X. Wang, 2021: Evaluation of CMIP6 Global Climate Models for Simulating Land Surface Energy and Water Fluxes During 1979–2014. Journal of Advances in Modeling Earth Systems, 13(6), e2021MS002515. doi: 10.1029/2021MS002515. This study examined the overall performance of the climate models in Phase 6 of the Coupled Model Intercomparison Project (CMIP6) in simulating the key energy and water fluxes over land. For this purpose, this study selected multiple land flux products as reference data sets and assessed the global spatial means, patterns, trends, seasonal cycles, and regional mean estimates of the sensible heat (SH), latent heat (LH), net radiation (RN), runoff (RF), and precipitation (PR) simulated by 32 CMIP6 models in recent decades. The global (Antarctica, Greenland, and hot deserts are not included) mean SH, LH, RN, RF, and PR simulated by the CMIP6 models are 37.55 ± 4.81 W m−2, 49.88 ± 5.31 W m−2, 89.10 ± 4.45 W m−2, 351.31 ± 95.28 mm yr−1, and 948.35 ± 88.77 mm yr−1, respectively. The ensemble median of CMIP6 simulations (CMIP6-MED) can provide robust estimates of global and regional land fluxes, which are within the ranges given by the reference data sets, and highly consistent spatiotemporal patterns of these fluxes. The comparison of CMIP6-MED with the first preferred reference data sets shows that CMIP6-MED generally overestimates the water and energy fluxes over land, except for the simulated RF and PR in the Amazon region. The most disagreements between CMIP6-MED and the reference data sets occur in South America (particularly the Amazon region) and the Tibetan Plateau. Finally, the sources of model biases are discussed. It is suggested that current land flux products should be widely used to optimize the structures and parameters of climate models in future work. model evaluation; CMIP6; land surface model; energy flux; water flux
Li, Jui-Lin F.; Xu, Kuan-Man; Richardson, Mark; Jiang, Jonathan H.; Stephens, Graeme; Lee, Wei-Liang; Fetzer, Eric; Yu, Jia-Yuh; Wang, Yi-Hui; Wang, F.-J.Li, J. F., K. Xu, M. Richardson, J. H. Jiang, G. Stephens, W. Lee, E. Fetzer, J. Yu, Y. Wang, F. Wang, 2021: Improved ice content, radiation, precipitation and low-level circulation over the tropical pacific from ECMWF ERA-interim to ERA5. Environmental Research Communications, 3(8), 081006. doi: 10.1088/2515-7620/ac1bfe. This study evaluates changes in simulated Pacific climate between two ECMWF re-analyses; the ERA Interim (ERAI) and the newest ERA5. Changes in the Integrated Forecasting System (IFS) and possibly sea surface temperature result in greatly reduced discrepancies in ERA5’s ice water path (IWP), radiative fluxes and precipitation relative to satellite-based observational products. IWP shows the largest percentage change, increasing by over 300% from ERAI to ERA5, due to inclusion of falling ice (snow) that impacts radiative calculation. ERAI to ERA5 changes in high-cloud fraction are generally anticorrelated as expected with outgoing longwave radiation, with ERA5 having smaller longwave discrepancies versus CERES observations compared with ERAI. Reflected shortwave discrepancies are similarly reduced from ERAI to ERA5, which appears to be due to changes in both cloud fraction and optical depth. Finally, ERA5 also reduces a longstanding precipitation excess relative to the GPCP observational product in the southern trade winds region between the Southern Pacific and intertropical convergence zones. This appears to be related to cooler prescribed sea surface temperatures, thereby reducing local moisture supply via suppressing net latent heat flux and stronger surface trade-winds. Compared with GPCP and CERES, ERA5 shows similar geographic patterns of discrepancies to ERAI in terms of precipitation and top-of-atmosphere radiation, but their magnitudes are greatly reduced in ERA5.
Li, Ming; Letu, Husi; Peng, Yiran; Ishimoto, Hiroshi; Lin, Yanluan; Nakajima, Takashi; Baran, Anthony; Guo, Zengyuan; Lei, Yonghui; Shi, JianchengLi, M., H. Letu, Y. Peng, H. Ishimoto, Y. Lin, T. Nakajima, A. Baran, Z. Guo, Y. Lei, J. Shi, 2021: Assessment of ice cloud modeling capabilities for the irregularly shaped Voronoi models in climate simulations with CAM5. Atmospheric Chemistry and Physics Discussions, 1-32. doi: 10.5194/acp-2021-208. Abstract. Climate models and satellite remote sensing applications require accurate descriptions of ice cloud optical and radiative properties through parameterization of their scattering properties. While abundant irregularly shaped ice particle habits present a challenge for modelling ice clouds. An irregularly shaped ice particle habit (Voronoi model) has been developed and recently suggested to be effective in inferring the microphysical and radiative properties of ice clouds from Himawari-8 and GCOM-C satellite measurements. As a continuation of previous work by Letu et al. (2016), in this study, we develop a broadband ice cloud scheme based on the Voronoi model through parameterization for use in the Community Atmosphere Model, Version 5 (CAM5). With single scattering properties of Voronoi model, ice cloud bulk scattering properties are integrate over particle size distributions of 11 field campaigns and are parameterized over particle effective diameter. The new ice cloud scheme is compared with four ice cloud schemes (the Yi, Mitchell, Baum-yang and Fu scheme), and is evaluated through the General circulation model version of the Rapid Radiative Transfer Model (RRTMG), and simulations of the top of atmosphere (TOA) shortwave and longwave cloud forcing (SWCF and LWCF) in CAM5. The Clouds and the Earth's Radiant Energy System (CERES) satellite data was selected as validation data. Results indicated that the Voronoi scheme can minimize differences between the satellite-based measurements and CAM5 simulations of global TOA SWCF compared to other four schemes, but performance is not significant for TOA LWCF. For tropical ice clouds, Voronoi scheme has advantages of ice cloud modelling capabilities for shortwave (SW) and longwave (LW) spectrum over other four schemes. In general, it is found that the Voronoi model has advantages over conventional ice cloud schemes and is sufficient for ice cloud modelling in climate simulations with CAM5.
Liang, Shunlin; Cheng, Jie; Jia, Kun; Jiang, Bo; Liu, Qiang; Xiao, Zhiqiang; Yao, Yunjun; Yuan, Wenping; Zhang, Xiaotong; Zhao, Xiang; Zhou, JiLiang, S., J. Cheng, K. Jia, B. Jiang, Q. Liu, Z. Xiao, Y. Yao, W. Yuan, X. Zhang, X. Zhao, J. Zhou, 2021: The Global LAnd Surface Satellite (GLASS) product suite. Bull. Amer. Meteor. Soc., (In Press). doi: 10.1175/BAMS-D-18-0341.1.
Liu, Lingling; Li, Yuanlong; Wang, FanLiu, L., Y. Li, F. Wang, 2021: MJO-Induced Intraseasonal Mixed Layer Depth Variability in the Equatorial Indian Ocean and Impacts on Subsurface Water Obduction. J. Phys. Oceanogr., 51(4), 1247-1263. doi: 10.1175/JPO-D-20-0179.1. AbstractChange of oceanic surface mixed layer depth (MLD) is critical for vertical exchanges between the surface and subsurface oceans and modulates surface temperature variabilities on various time scales. In situ observations have documented prominent intraseasonal variability (ISV) of MLD with 30–105-day periods in the equatorial Indian Ocean (EIO) where the Madden–Julian oscillation (MJO) initiates. Simulation of Hybrid Coordinate Ocean Model (HYCOM) reveals a regional maximum of intraseasonal MLD variability in the EIO (70°–95°E, 3°S–3°N) with a standard deviation of ~14 m. Sensitivity experiments of HYCOM demonstrate that, among all of the MJO-related forcing effects, the wind-driven downwelling and mixing are primary causes for intraseasonal MLD deepening and explain 83.7% of the total ISV. The ISV of MLD gives rise to high-frequency entrainments of subsurface water, leading to an enhancement of the annual entrainment rate by 34%. However, only a small fraction of these entrainment events (<20%) can effectively contribute to the annual obduction rate of 1.36 Sv, a quantification for the amount of resurfacing thermocline water throughout a year that mainly (84.6%) occurs in the summer monsoon season (May–October). The ISV of MLD achieves the maximal intensity in April–May and greatly affects the subsequent obduction. Estimation based on our HYCOM simulations suggests that MJOs overall reduce the obduction rate in the summer monsoon season by as much as 53%. A conceptual schematic is proposed to demonstrate how springtime intraseasonal MLD deepening events caused by MJO winds narrow down the time window for effective entrainment and thereby suppress the obduction of thermocline water.
Liu, Qiaozhen; Zhang, Zhaoyang; Fan, Meng; Wang, QuanLiu, Q., Z. Zhang, M. Fan, Q. Wang, 2021: The Divergent Estimates of Diffuse Radiation Effects on Gross Primary Production of Forest Ecosystems Using Light-Use Efficiency Models. Geophysical Research Letters, 48(19), e2021GL093864. doi: 10.1029/2021GL093864. Diffuse radiation can promote the vegetation photosynthesis. Radiation use efficiency (RUE = GPP/PAR) simulated by Terrestrial Ecosystem Carbon Flux GPP Model (TEC), Vegetation Photosynthesis Model (VPM), Eddy Covariance Light Use Efficiency Model (EC-LUE), and Diffuse Fraction-Based Two-Leaf Terrestrial Ecosystem Carbon Flux Model (DTEC) models were against the measured radiation-use efficiency (RUE) from FLUXNET under different bins of diffuse photosynthetically active radiation fraction (FDIFFPAR) in this study. Our results showed that the observed RUE increased linearly with FDIFFPAR. The differences of RUE between the first bin and other bin (RUEbin) from two big-leaf models were underestimated when the FDIFFPAR is higher than 0.5 except in evergreen broadleaf forests and RUEbin from the DTEC model was overestimated when the FDIFFPAR is higher than 0.7. The role of temperature and vapor pressure deficit in the diffuse radiation effects on vegetation photosynthesis was underestimated in EC-LUE, TEC, VPM. Although many studies applied LUE models to assess the effects of diffuse radiation on vegetation photosynthesis, our results suggested that these models were needed to be improved. diffuse fertilization effects (DFE); LUE models; Diffuse radiation fraction
Liu, Ziwei; Yang, HanboLiu, Z., H. Yang, 2021: Estimation of Water Surface Energy Partitioning With a Conceptual Atmospheric Boundary Layer Model. Geophysical Research Letters, 48(9), e2021GL092643. doi: 10.1029/2021GL092643. Open water surface evaporation (E) or the latent heat flux (λE) is of great importance to surface water and energy budget. However, partitioning of the available energy into sensible heat flux (H) and λE, quantified as the Bowen ratio (), is implicitly discrepant between models and observations. In this study, an explicit equation for the estimation of Bo (thus for the λE) is derived based on an atmospheric boundary layer model combined with the potential vapor pressure deficit budget. Derived equation only requires the air temperature (Ta) and specific humidity (Q) as inputs, and performs well in λE estimation with a relative error of
Loeb, Norman G.; Johnson, Gregory C.; Thorsen, Tyler J.; Lyman, John M.; Rose, Fred G.; Kato, SeijiLoeb, N. G., G. C. Johnson, T. J. Thorsen, J. M. Lyman, F. G. Rose, S. Kato, 2021: Satellite and Ocean Data Reveal Marked Increase in Earth’s Heating Rate. Geophysical Research Letters, 48(13), e2021GL093047. doi: 10.1029/2021GL093047. Earth's Energy Imbalance (EEI) is a relatively small (presently ∼0.3%) difference between global mean solar radiation absorbed and thermal infrared radiation emitted to space. EEI is set by natural and anthropogenic climate forcings and the climate system's response to those forcings. It is also influenced by internal variations within the climate system. Most of EEI warms the ocean; the remainder heats the land, melts ice, and warms the atmosphere. We show that independent satellite and in situ observations each yield statistically indistinguishable decadal increases in EEI from mid-2005 to mid-2019 of 0.50 ± 0.47 W m−2 decade−1 (5%–95% confidence interval). This trend is primarily due to an increase in absorbed solar radiation associated with decreased reflection by clouds and sea-ice and a decrease in outgoing longwave radiation (OLR) due to increases in trace gases and water vapor. These changes combined exceed a positive trend in OLR due to increasing global mean temperatures. CERES; Earth energy imbalance; planetary heat uptake
Luo, Rui; Ding, Qinghua; Wu, Zhiwei; Baxter, Ian; Bushuk, Mitchell; Huang, Yiyi; Dong, XiquanLuo, R., Q. Ding, Z. Wu, I. Baxter, M. Bushuk, Y. Huang, X. Dong, 2021: Summertime atmosphere–sea ice coupling in the Arctic simulated by CMIP5/6 models: Importance of large-scale circulation. Climate Dynamics, 56(5), 1467-1485. doi: 10.1007/s00382-020-05543-5. Summertime barotropic high pressure in the Arctic and its induced warmer and wetter atmosphere over sea ice are suggested to be important contributors to September sea ice loss on interannual and interdecadal time scales in the past decades. Using ERA5 and other reanalysis data, we find that atmospheric warming and moistening in the Arctic, synchronized by high latitude atmospheric circulation variability, work in tandem to melt sea ice through increasing downwelling longwave radiation at the surface. To what extent this atmosphere-longwave radiation-sea ice relationship can be captured in CMIP5 and 6 remains unknown and thus addressing this question is the objective of this study. To achieve this goal, we construct a process-oriented metric emphasizing the statistical relationship between atmospheric temperature and humidity with sea ice, which can effectively rank and differentiate the performance of 30 CMIP5 climate models in reproducing the observed connection. Based on our evaluation, we suggest that most available models in CMIP5 and 6 have a limitation in reproducing the full strength of the observed atmosphere–sea ice connection. This limitation likely stems from a weak impact of downwelling longwave radiation in linking sea ice with circulation associated with the weak sensitivity of the temperature and humidity fields to circulation variability in the Arctic. Thus, further efforts should be devoted to understanding the sources of these models’ limitations and improve skill in simulating the effects of atmospheric circulation in coupling temperature, humidity, surface radiation and sea ice together during Arctic summer.
Lutsko, Nicholas J.; Popp, Max; Nazarian, Robert H.; Albright, Anna LeaLutsko, N. J., M. Popp, R. H. Nazarian, A. L. Albright, 2021: Emergent Constraints on Regional Cloud Feedbacks. Geophysical Research Letters, 48(10), e2021GL092934. doi: 10.1029/2021GL092934. Low-cloud based emergent constraints have the potential to substantially reduce uncertainty in Earth’s equilibrium climate sensitivity, but recent work has shown that previously developed constraints fail in the latest generation of climate models, suggesting that new approaches are needed. Here, we investigate the potential for emergent constraints to reduce uncertainty in regional cloud feedbacks, rather than the global-mean cloud feedback. Strong relationships are found between the monthly and interannual variability of tropical clouds, and the tropical net cloud feedback. These relationships are combined with observations to substantially narrow the uncertainty in the tropical cloud feedback and demonstrate that the tropical cloud feedback is likely >0Wm−2K−1. Promising relationships are also found in the 90°–60°S and 30°–60°N regions, though these relationships are not robust across model generations and we have not identified the associated physical mechanisms. Climate sensitivity; cloud feedbacks; emergent constraint; tropical clouds
Ma, Hsi-Yen; Zhang, Kai; Tang, Shuaiqi; Xie, Shaocheng; Fu, RongMa, H., K. Zhang, S. Tang, S. Xie, R. Fu, 2021: Evaluation of the Causes of Wet-Season Dry Biases Over Amazonia in CAM5. Journal of Geophysical Research: Atmospheres, 126(11), e2020JD033859. doi: 10.1029/2020JD033859. This study investigates the causes of pronounced low precipitation bias over Amazonia in the Community Atmosphere Model version 5 (CAM5), a common feature in many global climate models. Our analysis is based on a suite of 3-day long hindcasts starting every day at 00Z from 1997 to 2012 and an AMIP simulation for the same period. The Amazonia dry bias appears by the second day in the hindcasts and is very robust for all the seasons with the largest bias magnitude during the wet season (December–February). The bias pattern and magnitude do not change much during different dynamical wind regimes on sub-seasonal time scales. We further classify the diurnal cycle of precipitation near the LBA sites from observations and hindcasts into three convective regimes: no precipitation, late afternoon deep convection, and nighttime deep convection. CAM5 can only simulate the late afternoon convective regime and completely fails to simulate the nighttime convection, which is mostly from propagating convective systems originating from remote locations. CAM5 mainly underestimates precipitation in the late afternoon and nighttime convective regimes, which occur during ∼67% of wet season days and account for ∼75% of accumulated precipitation amount in observations. The persistent warm temperature bias and slightly higher moisture below 850 mb likely trigger deep convection too frequently, resulting in an earlier but weaker rainfall peak in the diurnal cycle. Furthermore, shallow convection may not effectively transport moisture from boundary layer to the free atmosphere, which also leads to weaker deep convection events.
Ma, Qianrong; You, Qinglong; Ma, Yujun; Cao, Yu; Zhang, Jie; Niu, Miaomiao; Zhang, YuqingMa, Q., Q. You, Y. Ma, Y. Cao, J. Zhang, M. Niu, Y. Zhang, 2021: Changes in cloud amount over the Tibetan Plateau and impacts of large-scale circulation. Atmospheric Research, 249, 105332. doi: 10.1016/j.atmosres.2020.105332. Using the Clouds and Earth's Radiant Energy System (CERES) Edition 4 dataset, characteristics and variations of cloud amounts over the Tibetan Plateau (Tibet) during 2001–2019 was analyzed. Our results reveal that the mid–high cloud cover (MHCC) constitutes the major proportion and shows similar seasonal variations and annual cycle to the total cloud cover (TCC). The high cloud cover (HCC) has the greatest seasonal variation, whereas the mid–low cloud cover (MLCC) has the least variation. TCC, MHCC, and HCC exhibit the largest values in summer. The summer TCC, MHCC and MLCC exhibited decreasing trends and MHCC is more significant. The summer HCC shows increasing trend. Clouds at different heights show different correlations with skin temperature, and decreased TCC likely influences recent warming over the Tibet. The increased skin temperature is mainly adjusted by the decreased cloud amount especially MHCC. Cloud amounts are highly responsible for the precipitation, and the summer precipitation over the Tibet is mainly influenced by HCC, followed by MHCC. The decreasing TCC is related to two Rossby wave trains over Eurasia, corresponding to the Eurasian teleconnection pattern and Silk Road pattern. They induce an anomalous anti-cyclone in north Tibet and restrain ascending motions. Meanwhile, the South Asia High weakens and further enhances the sinking movements. Precipitation; Cloud amounts; Rossby wave trains; South Asia High; Surface temperature
Mackie, Anna; Brindley, Helen E.; Palmer, Paul I.Mackie, A., H. E. Brindley, P. I. Palmer, 2021: Contrasting observed atmospheric responses to tropical SST warming patterns. Journal of Geophysical Research: Atmospheres, n/a(n/a), e2020JD033564. doi: https://doi.org/10.1029/2020JD033564. Equilibrium climate sensitivity (ECS) is a theoretical concept which describes the change in global mean surface temperature that results from a sustained doubling of atmospheric CO2. Current ECS estimates range from ∼1.8–5.6K, reflecting uncertainties in climate feedbacks. The sensitivity of the lower (1000-700 hPa) and upper (500-200 hPa) troposphere to changes in spatial patterns of tropical sea surface temperature (SST) have been proposed by recent model studies as key feedbacks controlling climate sensitivity. We examine empirical evidence for these proposed mechanisms using 14 years of satellite data. We examine the response of temperature and humidity profiles, clouds and top-of-the-atmosphere (TOA) radiation to relative warming in tropical ocean regions when there is either strong convection or subsidence. We find warmer SSTs in regions of strong subsidence are coincident with a decrease in lower tropospheric stability (-0.9±0.4 KK−1) and low cloud cover ( ∼-6 %K−1). This leads to a warming associated with the weakening in the shortwave cooling effect of clouds (4.2±1.9 Wm−2K−1), broadly consistent with model calculations. In contrast, warmer SSTs in regions of strong convection are coincident with an increase in upper tropospheric humidity (3.2±1.5 %K−1). In this scenario, the dominant effect is the enhancement of the warming longwave cloud radiative effect (3.8±3.0 Wm−2K−1 ) from an increase in high cloud cover ( ∼7 %K−1), though changes in the net (longwave and shortwave) effect are not statistically significant (p < 0.003). Our observational evidence supports the existence of mechanisms linking contrasting atmospheric responses to patterns in SST, mechanisms which have been linked to climate sensitivity. Climate sensitivity; Satellite observations; SST warming patterns; Tropical atmosphere
Marcianesi, F.; Aulicino, G.; Wadhams, P.Marcianesi, F., G. Aulicino, P. Wadhams, 2021: Arctic sea ice and snow cover albedo variability and trends during the last three decades. Polar Science, (In Press). doi: 10.1016/j.polar.2020.100617. The aim of the present study is to assess the full effect on the albedo of both sea ice extent decrease and snowline retreat in the Arctic during the last three decades. Averaged over the globe, the overall warming effect due to Arctic land and ocean albedo change corresponds to adding about 44% to the direct effect of human CO2 emissions during the same period. In fact, the area and thickness of Arctic sea ice have both been declining in this time frame. This has caused feedbacks affecting the whole global climate system. One such is albedo feedback of sea ice shrinking which was previously estimated (Pistone et al., 2014) to add about 25% to the direct warming effect of anthropogenic CO2 emissions. In this study, we demonstrate that the role of snowline retreat in albedo decrease is comparable to that of sea ice shrinking. To this aim, we estimate the radiative forcing (W/m2) due to snow and ice decrease during 34 years (1982–2015) from the analysis of changes of observed albedo based on the Clouds and the Earth's Radiant Energy System Energy Balanced And Filled (CERES EBAF) dataset, paired with sea ice and snow cover data from the US National Snow & Ice Data Center (NSIDC). Arctic; Albedo change; Global climate; Sea ice decrease; Snowline retreat
Mardi, Ali Hossein; Dadashazar, Hossein; Painemal, David; Shingler, Taylor; Seaman, Shane T.; Fenn, Marta A.; Hostetler, Chris A.; Sorooshian, ArminMardi, A. H., H. Dadashazar, D. Painemal, T. Shingler, S. T. Seaman, M. A. Fenn, C. A. Hostetler, A. Sorooshian, 2021: Biomass Burning Over the United States East Coast and Western North Atlantic Ocean: Implications for Clouds and Air Quality. Journal of Geophysical Research: Atmospheres, 126(20), e2021JD034916. doi: 10.1029/2021JD034916. Biomass burning (BB) aerosol events were characterized over the U.S. East Coast and Bermuda over the western North Atlantic Ocean (WNAO) between 2005 and 2018 using a combination of ground-based observations, satellite data, and model outputs. Days with BB influence in an atmospheric column (BB days) were identified using criteria biased toward larger fire events based on anomalously high AERONET aerosol optical depth (AOD) and MERRA-2 black carbon (BC) column density. BB days are present year-round with more in June–August (JJA) over the northern part of the East Coast, in contrast to more frequent events in March–May (MAM) over the southeast U.S. and Bermuda. BB source regions in MAM are southern Mexico and by the Yucatan, Central America, and the southeast U.S. JJA source regions are western parts of North America. Less than half of the BB days coincide with anomalously high PM2.5 levels in the surface layer, according to data from 14 IMPROVE sites over the East Coast. Profiles of aerosol extinction suggest that BB particles can be found in the boundary layer and into the upper troposphere with the potential to interact with clouds. Higher cloud drop number concentration and lower drop effective radius are observed during BB days. In addition, lower liquid water path is found during these days, especially when BB particles are present in the boundary layer. While patterns are suggestive of cloud-BB aerosol interactions over the East Coast and the WNAO, additional studies are needed for confirmation. ACTIVATE; smoke; aerosol-cloud interaction; EVS-3; biomass burning; HSRL
Marti, Florence; Blazquez, Alejandro; Meyssignac, Benoit; Ablain, Michaël; Barnoud, Anne; Fraudeau, Robin; Jugier, Rémi; Chenal, Jonathan; Larnicol, Gilles; Pfeffer, Julia; Restano, Marco; Benveniste, JérômeMarti, F., A. Blazquez, B. Meyssignac, M. Ablain, A. Barnoud, R. Fraudeau, R. Jugier, J. Chenal, G. Larnicol, J. Pfeffer, M. Restano, J. Benveniste, 2021: Monitoring the ocean heat content change and the Earth energy imbalance from space altimetry and space gravimetry. Earth System Science Data Discussions, 1-32. doi: 10.5194/essd-2021-220. Abstract. The Earth energy imbalance (EEI) at the top of the atmosphere is responsible for the accumulation of heat in the climate system. Monitoring the EEI is therefore necessary to better understand the Earth’s warming climate. Measuring the EEI is challenging as it is a globally integrated variable whose variations are small (0.5–1 W m−2) compared to the amount of energy entering and leaving the climate system (~ 340 W m−2). Since the ocean absorbs more than 90 % of the excess energy stored by the Earth system, estimating the ocean heat content (OHC) provides an accurate proxy of the EEI. This study provides a space geodetic estimation of the OHC changes at global and regional scales based on the combination of space altimetry and space gravimetry measurements. From this estimate, the global variations in the EEI are derived with realistic estimates of its uncertainty. The mean EEI value is estimated at +0.74 ± 0.22 W m−2 (90 % confidence level) between August 2002 and August 2016. Comparisons against independent estimates based on Argo data and on CERES measurements show good agreement within the error bars of the global mean and the time variations in EEI. Further improvements are needed to reduce uncertainties and to improve the time series especially at interannual and smaller time scales. The space geodetic OHC-EEI product is freely available at https://doi.org/10.24400/527896/a01-2020.003.
Matthews, G.Matthews, G., 2021: CERES Replacement “Libera” SI Traceable Measurement Spectral Calibration Concept using Direct Solar Views by High Resolution Earth Telescopes. J. Atmos. Oceanic Technol., -1(aop). doi: 10.1175/JTECH-D-21-0002.1. AbstractBetter predictions of global warming can be enabled by tuning legacy and current computer simulations to Earth Radiation Budget (ERB) measurements. Since the 1970’s, such orbital results exist, and the next generation instruments called “Libera” are in design. Climate communities have requested that ERB observing system calibration accuracy obtain significantly better SI traceability and stability improvements. This is to prevent untracked instrument calibration drifts, that could lead to false conclusions on climate change. Based on experience from previous ERB missions, the concept presented here utilizes solar calibration for cloud size Earth measurement resolution, at ≪1% accuracy. However it neglects shown to be unsuccessful calibration technology like solar diffusers and on-board lights, as used by ERBE, ScaRaB, CERES, GERB & other Libera designs etc. New spectral characterizing concepts are therefore introduced. This allows in-flight wavelength dependent calibration of Earth observing Libera telescopes using direct solar views, through narrow-band filters continuously characterized on-orbit.
Matthews, GrantMatthews, G., 2021: NASA CERES Spurious Calibration Drifts Corrected by Lunar Scans to Show the Sun Is not Increasing Global Warming and Allow Immediate CRF Detection. Geophysical Research Letters, 48(15), e2021GL092994. doi: 10.1029/2021GL092994. Orbital Earth Radiation Budget measurement comparisons to models, are critical for climate prediction confidence. Satellite systems must reduce calibration drifts for this purpose. NASA Clouds and the Earth's Radiant Energy System (CERES) measures Earth albedo reductions that if correct, would increase solar forcing and suggest greater sunlight absorption is driving much of recent temperature increases. Such results are presented, alongside those from the Moon and Earth Radiation Budget Experiment (MERBE). MERBE uses constant lunar reflectivity for tracking and compensation of instrument telescope degradation, undetectable by CERES. MERBE finds Earth albedo constant compared to that of the Moon, because Arctic solar warming effects are balanced by solar cooling elsewhere, likely due to negative feedbacks. Contrary to NASA, this shows the Sun is not increasing warming and that CERES results are not as stable as claimed and assumed. Furthermore, MERBE can actually resolve Cloud Radiative Forcing (CRF) signals from the existing record, rather than in decades with official observations. earth radiation budget; CERES; climate; Albedo; solar; MERBE
Mayer, Johannes; Mayer, Michael; Haimberger, LeopoldMayer, J., M. Mayer, L. Haimberger, 2021: Consistency and Homogeneity of Atmospheric Energy, Moisture, and Mass Budgets in ERA5. J. Climate, 34(10), 3955-3974. doi: 10.1175/JCLI-D-20-0676.1. AbstractThis study uses advanced numerical and diagnostic methods to evaluate the atmospheric energy budget with the fifth major global reanalysis produced by ECMWF (ERA5) in combination with observed and reconstructed top of the atmosphere (TOA) energy fluxes for the period 1985–2018. We assess the meridional as well as ocean–land energy transport and perform internal consistency checks using mass-balanced data. Furthermore, the moisture and mass budgets in ERA5 are examined and compared with previous budget evaluations using ERA-Interim as well as observation-based estimates. Results show that peak annual mean meridional atmospheric energy transports in ERA5 (4.58 ± 0.07 PW in the Northern Hemisphere) are weaker compared to ERA-Interim (4.74 ± 0.09 PW), where the higher spatial and temporal resolution of ERA5 can be excluded as a possible reason. The ocean–land energy transport in ERA5 is reliable at least from 2000 onward (~2.5 PW) such that the imbalance between net TOA fluxes and lateral energy fluxes over land are on the order of ~1 W m−2. Spinup and spindown effects as revealed from inconsistencies between analyses and forecasts are generally smaller and temporally less variable in ERA5 compared to ERA-Interim. Evaluation of the moisture budget shows that the ocean–land moisture transport and parameterized freshwater fluxes agree well in ERA5, while there are large inconsistencies in ERA-Interim. Overall, the quality of the budgets derived from ERA5 is demonstrably better than estimates from ERA-Interim. Still some particularly sensitive budget quantities (e.g., precipitation, evaporation, and ocean–land energy transport) show apparent inhomogeneities, especially in the late 1990s, which warrant further investigation and need to be considered in studies of interannual variability and trends.
Mazhar, Usman; Jin, Shuanggen; Duan, Wentao; Bilal, Muhammad; Ali, Md Arfan; Farooq, HasnainMazhar, U., S. Jin, W. Duan, M. Bilal, M. A. Ali, H. Farooq, 2021: Spatio-Temporal Trends of Surface Energy Budget in Tibet from Satellite Remote Sensing Observations and Reanalysis Data. Remote Sensing, 13(2), 256. doi: 10.3390/rs13020256. Being the highest and largest land mass of the earth, the Tibetan Plateau has a strong impact on the Asian climate especially on the Asian monsoon. With high downward solar radiation, the Tibetan Plateau is a climate sensitive region and the main water source for many rivers in South and East Asia. Although many studies have analyzed energy fluxes in the Tibetan Plateau, a long-term detailed spatio-temporal variability of all energy budget parameters is not clear for understanding the dynamics of the regional climate change. In this paper, satellite remote sensing and reanalysis data are used to quantify spatio-temporal trends of energy budget parameters, net radiation, latent heat flux, and sensible heat flux over the Tibetan Plateau from 2001 to 2019. The validity of both data sources is analyzed from in situ ground measurements of the FluxNet micrometeorological tower network, which verifies that both datasets are valid and reliable. It is found that the trend of net radiation shows a slight increase. The latent heat flux increases continuously, while the sensible heat flux decreases continuously throughout the study period over the Tibetan Plateau. Varying energy fluxes in the Tibetan plateau will affect the regional hydrological cycle. Satellite LE product observation is limited to certain land covers. Thus, for larger spatial areas, reanalysis data is a more appropriate choice. Normalized difference vegetation index proves a useful indicator to explain the latent heat flux trend. Despite the reduction of sensible heat, the atmospheric temperature increases continuously resulting in the warming of the Tibetan Plateau. The opposite trend of sensible heat flux and air temperature is an interesting and explainable phenomenon. It is also concluded that the surface evaporative cooling is not the indicator of atmospheric cooling/warming. In the future, more work shall be done to explain the mechanism which involves the complete heat cycle in the Tibetan Plateau. surface energy budget; ERA5; energy flux trends; optical remote sensing; tibetan plateau
Miao, Hao; Wang, Xiaocong; Liu, Yimin; Wu, GuoxiongMiao, H., X. Wang, Y. Liu, G. Wu, 2021: A Regime-Based Investigation Into the Errors of CMIP6 Simulated Cloud Radiative Effects Using Satellite Observations. Geophysical Research Letters, 48(18), e2021GL095399. doi: 10.1029/2021GL095399. Using a variety of CloudSat/CALIPSO products, this study synergistically examines the performance of clouds and their radiative effects (CRE) for models participating in CMIP6. Results show virtually all models overestimate the net cooling effect of clouds, which is caused by the overestimation of shortwave CRE and the underestimation of longwave CRE. By dividing clouds into regimes jointly sorted by cloud water path and cloud cover, we found models commonly underestimate the relative frequency of occurrence (RFO) for clouds that are geometrically thick, and the bias of RFO is dominant over that of within-regime CRE in an error decomposition of total CRE. This results in underestimations of CRE in geometrically thick clouds, which are partially offset by overestimations in the remaining cloud regimes, leading to the globally averaged CRE being less biased. The consideration of regime-based CRE gives important information that could be used for correction of cloud parameterization in models.
Ming, Yi; Loeb, Norman G.; Lin, Pu; Shen, Zhaoyi; Naik, Vaishali; Singer, Clare E.; Ward, Ryan X.; Paulot, Fabien; Zhang, Zhibo; Bellouin, Nicolas; Horowitz, Larry W.; Ginoux, Paul A.; Ramaswamy, V.Ming, Y., N. G. Loeb, P. Lin, Z. Shen, V. Naik, C. E. Singer, R. X. Ward, F. Paulot, Z. Zhang, N. Bellouin, L. W. Horowitz, P. A. Ginoux, V. Ramaswamy, 2021: Assessing the Influence of COVID-19 on the Shortwave Radiative Fluxes Over the East Asian Marginal Seas. Geophysical Research Letters, 48(3), e2020GL091699. doi: https://doi.org/10.1029/2020GL091699. The Coronavirus Disease 2019 (COVID-19) pandemic led to a widespread reduction in aerosol emissions. Using satellite observations and climate model simulations, we study the underlying mechanisms of the large decreases in solar clear-sky reflection (3.8 W m−2 or 7%) and aerosol optical depth (0.16 W m−2 or 32%) observed over the East Asian Marginal Seas in March 2020. By separating the impacts from meteorology and emissions in the model simulations, we find that about one-third of the clear-sky anomalies can be attributed to pandemic-related emission reductions, and the rest to weather variability and long-term emission trends. The model is skillful at reproducing the observed interannual variations in solar all-sky reflection, but no COVID-19 signal is discerned. The current observational and modeling capabilities will be critical for monitoring, understanding, and predicting the radiative forcing and climate impacts of the ongoing crisis.
Miyamoto, Ayumu; Nakamura, Hisashi; Miyasaka, Takafumi; Kosaka, YuMiyamoto, A., H. Nakamura, T. Miyasaka, Y. Kosaka, 2021: Radiative Impacts of Low-Level Clouds on the Summertime Subtropical High in the South Indian Ocean Simulated in a Coupled General Circulation Model. J. Climate, 34(10), 3991-4007. doi: 10.1175/JCLI-D-20-0709.1. AbstractOver the south Indian Ocean, the coupled system of the subtropical Mascarene high and low-level clouds exhibits marked seasonality. To investigate this seasonality, the present study assesses radiative impacts of low-level clouds on the summertime Mascarene high with a coupled general circulation model. Comparison between a fully coupled control simulation and a “no-low-cloud simulation,” where the radiative effects of low-level clouds are artificially turned off, demonstrates that they act to reinforce the Mascarene high. Their impacts are so significant that the summertime Mascarene high almost disappears in the no-low-cloud experiment, suggesting their essential role in the existence of the summertime Mascarene high. As the primary mechanism, lowered sea surface temperature by the cloud albedo effect suppresses deep convective precipitation, inducing a Matsuno–Gill type response that reinforces the high, as verified through an atmospheric dynamical model diagnosis. Associated reduction of high-top clouds, as well as increased low-level clouds, augments in-atmosphere radiative cooling, which further reinforces the high. The present study reveals that low-level clouds constitute a tight positive feedback system with the subtropical high via sea surface temperature over the summertime south Indian Ocean.
Monroe, Emily E.; Taylor, Patrick C.; Boisvert, Linette N.Monroe, E. E., P. C. Taylor, L. N. Boisvert, 2021: Arctic Cloud Response to a Perturbation in Sea Ice Concentration: The North Water Polynya. Journal of Geophysical Research: Atmospheres, 126(16), e2020JD034409. doi: 10.1029/2020JD034409. Surface and atmosphere energy exchanges play an important role in the Arctic climate system by influencing the lower atmospheric stability and humidity, sea ice melt and growth, and surface temperature. Sea ice significantly alters the character of these energy exchanges relative to ice-free ocean. The observed decline in Arctic sea ice since 1979 motivates questions related to the evolving role of surface-atmosphere coupling and potential feedbacks on the Arctic system. Due to the strong wintertime cloud warming effect, a critical question concerns the potential response of low clouds to Arctic sea ice decline. Previous approaches relied on interannual variability to investigate the cloud response to sea ice decline. However, the covariation between atmospheric conditions and sea ice makes it difficult to define an observational control when using interannual variability. To circumvent this difficulty, we exploit the recurring North Water polynya, an episodic opening in the northern Baffin Bay sea ice, as a natural laboratory to isolate the cloud response to a rapid, near-step perturbation in sea ice. Our results show that during the event, (a) low-cloud cover is 10%–33% larger over the polynya than nearby sea ice, (b) cloud liquid water content is up to 400% larger over the polynya than nearby sea ice, and (c) the surface cloud radiative effect is 18 W m−2 larger over the polynya than nearby sea ice. Our results provide evidence that the low-cloud response during a polynya is a positive feedback lengthening the event. sea ice; cloud radiative effects; Arctic clouds; North Water; polynya; surface turbulent flux
Myers, Timothy A.; Scott, Ryan C.; Zelinka, Mark D.; Klein, Stephen A.; Norris, Joel R.; Caldwell, Peter M.Myers, T. A., R. C. Scott, M. D. Zelinka, S. A. Klein, J. R. Norris, P. M. Caldwell, 2021: Observational constraints on low cloud feedback reduce uncertainty of climate sensitivity. Nature Climate Change, 11(6), 501-507. doi: 10.1038/s41558-021-01039-0. Marine low clouds strongly cool the planet. How this cooling effect will respond to climate change is a leading source of uncertainty in climate sensitivity, the planetary warming resulting from CO2 doubling. Here, we observationally constrain this low cloud feedback at a near-global scale. Satellite observations are used to estimate the sensitivity of low clouds to interannual meteorological perturbations. Combined with model predictions of meteorological changes under greenhouse warming, this permits quantification of spatially resolved cloud feedbacks. We predict positive feedbacks from midlatitude low clouds and eastern ocean stratocumulus, nearly unchanged trade cumulus and a near-global marine low cloud feedback of 0.19 ± 0.12 W m−2 K−1 (90% confidence). These constraints imply a moderate climate sensitivity (~3 K). Despite improved midlatitude cloud feedback simulation by several current-generation climate models, their erroneously positive trade cumulus feedbacks produce unrealistically high climate sensitivities. Conversely, models simulating erroneously weak low cloud feedbacks produce unrealistically low climate sensitivities.
Needham, Michael R.; Randall, David A.Needham, M. R., D. A. Randall, 2021: Linking Atmospheric Cloud Radiative Effects and Tropical Precipitation. Geophysical Research Letters, 48(14), e2021GL094004. doi: 10.1029/2021GL094004. Studies in recent decades have demonstrated a robust relationship between tropical precipitation and column relative humidity (CRH). The present study identifies a similar relationship between CRH and the atmospheric cloud radiative effect (ACRE) calculated from satellite observations. Like precipitation, the ACRE begins to increase rapidly when CRH exceeds a critical value near 70%. We show that the ACRE can be estimated from CRH, similar to the way that CRH has been used to estimate precipitation. Our method reproduces the annual mean spatial structure of the ACRE in the tropics, and skillfully estimates the mean ACRE on monthly and daily time scales in six regions of the tropics. We propose that the exponential dependence of precipitation on CRH may be partially explained by cloud-longwave feedbacks, which facilitate a shift from convective to stratiform conditions. tropical precipitation; atmospheric cloud radiative effect; cloud longwave feedback; column relative humidity
Nga, Pham Thi Thanh; Ha, Pham Thanh; Hang, Vu ThanhNga, P. T. T., P. T. Ha, V. T. Hang, 2021: Satellite-Based Regionalization of Solar Irradiation in Vietnam by k-Means Clustering. J. Appl. Meteor. Climatol., 60(3), 391-402. doi: 10.1175/JAMC-D-20-0070.1. AbstractThis study presents the application of k-means clustering to satellite-based solar irradiation in different regions of Vietnam. The solar irradiation products derived from the Himawari-8 satellite, named AMATERASS by the solar radiation consortium under the Japan Science and Technology Agency (JST), are validated with observations recorded at five stations in the period from October 2017 to September 2018 before their use for clustering. High correlations among them enable the use of satellite-based daily global horizontal irradiation for spatial variability analysis and regionalization. With respect to the climate regime in Vietnam, the defined 6-cluster groups demonstrate better agreement with the conventionally classified seven climatic zones rather than the four climatic zones of the Köppen classification. The spatial distribution and seasonal variation in the regionalized solar irradiation reflect interchangeable influences of large-scale atmospheric circulation in terms of the East Asian winter monsoon and the South Asian summer monsoon as well as the effect of local topography. Higher daily averaged solar radiation and its weaker seasonal variation were found in two clusters in the southern region where the South Asian summer monsoon dominates in the rainy season. Pronounced seasonal variability in solar irradiation in four clusters in the northern region is associated with the influence of the East Asian monsoon, resulting in its clear reduction during the winter months.
Noda, Akira T.; Seiki, Tatsuya; Roh, Woosub; Satoh, Masaki; Ohno, TomokiNoda, A. T., T. Seiki, W. Roh, M. Satoh, T. Ohno, 2021: Improved Representation of Low-Level Mixed-Phase Clouds in a Global Cloud-System-Resolving Simulation. Journal of Geophysical Research: Atmospheres, 126(17), e2021JD035223. doi: 10.1029/2021JD035223. Low-level mixed-phase clouds are important for Earth's climate but are poorly represented in climate models. A one-moment microphysics scheme from Seiki and Roh (2020, https://doi.org/10.1175/JAS-D-19-0266.1) improves the representation of supercooled water and verifies it with a single-column model. We evaluate the performance of this scheme using a global cloud-system-resolving simulation. We show that the scheme has several major improvements over the original scheme on which it is based, which underestimated the generation of supercooled droplets. The new scheme suppresses the original scheme's tendency to overestimate the conversion of cloud water to rain, vapor to cloud ice, and cloud water to cloud ice. It greatly improves the previously underestimated production of low-level mixed-phase clouds at middle-to-high latitudes, particularly over the ocean at the middle latitudes of the Southern Hemisphere. It also increases the lifetime of liquid clouds, thus improving the simulation of low-level liquid clouds in western coastal regions of the tropics. The temperature dependency of the ratio of mass fraction of liquid cloud to the sum of ice and liquid clouds, F, reveals that mixed-phase clouds statistically develop in a much wider range of temperature (−30°C ∼ 0°C), which supports the development of more mixed-phase clouds in our simulation. The change to a wider range of F at given temperature is expected to be important, because it allows more complex feedback processes to arise from different cloud phase regimes. An improved simulation in seasonal variation of shortwave radiation and its cloud radiative effect are also identified. cloud microphysics; mixed-phase clouds; global cloud-resolving model; supercooled water; seasonal variation
Obregón, María Ángeles; Serrano, Antonio; Costa, Maria João; Silva, Ana MariaObregón, M. Á., A. Serrano, M. J. Costa, A. M. Silva, 2021: Global Spatial and Temporal Variation of the Combined Effect of Aerosol and Water Vapour on Solar Radiation. Remote Sensing, 13(4), 708. doi: 10.3390/rs13040708. This study aims to calculate the combined and individual effects of the optical thickness of aerosols (AOT) and precipitable water vapour (PWV) on the solar radiation reaching the Earth’s surface at a global scale and to analyse its spatial and temporal variation. For that purpose, a novel but validated methodology is applied to CERES SYN1deg products for the period 2000–2019. Spatial distributions of AOT and PWV effects, both individually and combined, show a close link with the spatial distributions of AOT and PWV. The spatially averaged combined effect results in a −13.9% reduction in irradiance, while the average AOT effect is −2.3%, and the PWV effect is −12.1%. The temporal analysis focuses on detecting trends in the anomalies. The results show overall positive trends for AOT and PWV. Consequently, significant negative overall trends are found for the effects. However, significant positive trends for the individual AOT and the combined AOT-PWV effects are found in specific regions, such as the eastern United States, Europe or Asia, indicating successful emission control policies in these areas. This study contributes to a better understanding of the individual and combined effects of aerosols and water vapour on solar radiation at a global scale. CERES; aerosol optical depth; precipitable water vapour; combined effects; global radiative effects
Okamoto, Kozo; Hayashi, Masahiro; Hashino, Tempei; Nakagawa, Masayuki; Okuyama, ArataOkamoto, K., M. Hayashi, T. Hashino, M. Nakagawa, A. Okuyama, 2021: Examination of all-sky infrared radiance simulation of Himawari-8 for global data assimilation and model verification. Quarterly Journal of the Royal Meteorological Society, 147(740), 3611-3627. doi: 10.1002/qj.4144. The systematic difference between observations and simulation from weather forecast model hampers effective data assimilation and model improvement. The purpose of this study is to identify the characteristics and cause of the systematic difference or observation-minus-background (O − B) bias for all-sky infrared radiances of the Himawari-8 satellite, and propose data assimilation preprocessings and model verification. The O − B bias in cloudy scenes showed substantial negative values because of the shortage of high-altitude clouds generated in the forecast model. Additionally, a positive bias appeared for thin ice clouds because of the excessive absorption of radiative transfer models (RTMs). These biases were traced based on a bottom-up approach investigating individual uncertainty of RTMs, observation calibration, and the forecast model using two RTMs, reference hyperspectral sounders and synergetic measurements of CloudSat and CALIPSO. Based on these findings, data assimilation preprocessing such as quality-control procedures excluding samples that models poorly reproduced was developed. Although the quality controls reduced the number of biased samples, non-negligible O − B biases remained. Possible problems and treatments for the biases were discussed, including bias correction, observation error inflation, and correction of the cloud effect parameter. The O–B statistics also suggested insufficient representation of the diurnal variation in the cloud fraction in the tropics. Modified physical processes in the forecast model to increase ice clouds were tested to help improve the model bias and develop data assimilation. This trial indicated the difficulty in improving both O − B bias and variance and the necessity of adjusting the cloud effect parameters in data assimilation. cloud; data assimilation; bias; Himawari-8; radiative transfer model; all-sky infrared radiance
Painemal, David; Corral, Andrea F.; Sorooshian, Armin; Brunke, Michael A.; Chellappan, Seethala; Gorooh, Vesta Afzali; Ham, Seung-Hee; O'Neill, Larry; Smith, William L.; Tselioudis, George; Wang, Hailong; Zeng, Xubin; Zuidema, PaquitaPainemal, D., A. F. Corral, A. Sorooshian, M. A. Brunke, S. Chellappan, V. A. Gorooh, S. Ham, L. O'Neill, W. L. Smith, G. Tselioudis, H. Wang, X. Zeng, P. Zuidema, 2021: An Overview of Atmospheric Features Over the Western North Atlantic Ocean and North American East Coast—Part 2: Circulation, Boundary Layer, and Clouds. Journal of Geophysical Research: Atmospheres, 126(6), e2020JD033423. doi: https://doi.org/10.1029/2020JD033423. The Western North Atlantic Ocean (WNAO) is a complex land-ocean-atmosphere system that experiences a broad range of atmospheric phenomena, which in turn drive unique aerosol transport pathways, cloud morphologies, and boundary layer variability. This work, Part 2 of a 2-part paper series, provides an overview of the atmospheric circulation, boundary layer variability, three-dimensional cloud structure, and precipitation over the WNAO; the companion paper (Part 1) focused on chemical characterization of aerosols, gases, and wet deposition. Seasonal changes in atmospheric circulation and sea surface temperature explain a clear transition in cloud morphologies from small shallow cumulus clouds, convective clouds, and tropical storms in summer, to stratus/stratocumulus and multilayer cloud systems associated with winter storms. Synoptic variability in cloud fields is estimated using satellite-based weather states, and the role of postfrontal conditions (cold-air outbreaks) in the development of stratiform clouds is further analyzed. Precipitation is persistent over the ocean, with a regional peak over the Gulf Stream path, where offshore sea surface temperature gradients are large and surface fluxes reach a regional peak. Satellite data show a clear annual cycle in cloud droplet number concentration with maxima (minima) along the coast in winter (summer), suggesting a marked annual cycle in aerosol-cloud interactions. Compared with satellite cloud retrievals, four climate models qualitatively reproduce the annual cycle in cloud cover and liquid water path, but with large discrepancies across models, especially in the extratropics. The paper concludes with a summary of outstanding issues and recommendations for future work. air-sea interactions; atmospheric boundary layer; climate model evaluation; stratiform clouds; Western North Atlantic
Painemal, David; Spangenberg, Douglas; Smith Jr., William L.; Minnis, Patrick; Cairns, Brian; Moore, Richard H.; Crosbie, Ewan; Robinson, Claire; Thornhill, Kenneth L.; Winstead, Edward L.; Ziemba, LukePainemal, D., D. Spangenberg, W. L. Smith Jr., P. Minnis, B. Cairns, R. H. Moore, E. Crosbie, C. Robinson, K. L. Thornhill, E. L. Winstead, L. Ziemba, 2021: Evaluation of satellite retrievals of liquid clouds from the GOES-13 Imager and MODIS over the midlatitude North Atlantic during NAAMES campaign. Atmospheric Measurement Techniques Discussions, 1-23. doi: 10.5194/amt-2021-7. Abstract. Satellite retrievals of cloud droplet effective radius (re) and optical depth (t) from the Thirteenth Geostationary Operational Environmental Satellite (GOES-13), and the MOderate resolution Imaging Spectroradiometer (MODIS) onboard Aqua and Terra are evaluated with airborne data collected over the midlatitude boundary layer during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). The airborne dataset comprises in-situ re from the Cloud Droplet Probe (CDP) and remotely sensed re and t from the airborne Research Scanning Polarimeter (RSP). GOES-13 and MODIS (Aqua and Terra) re values are systematically greater than those from the CDP and RSP by at least 4.8 um (GOES-13) and 1.7 um (MODIS) despite relatively high linear correlations coefficients (r = 0.52–0.68). In contrast, the satellite t underestimates its RSP counterpart by −3.0, with r = 0.76–077. Overall, MODIS yields better agreement with airborne data than GOES-13, with biases consistent with those reported for subtropical stratocumulus clouds. While the negative bias in satellite t is mostly due to the retrievals having been collected in highly heterogeneous cloud scenes, the causes for the positive bias in satellite re, especially for GOES-13, are more complex. Although the high viewing zenith angle (~65°) and coarser pixel resolution for GOES-13 could explain a re bias of at least 0.7 um, the higher GOES-13 re bias relative to that from MODIS is likely rooted in other factors. In this regard, a near monotonic increase was also observed in GOES-13 re up to 1.0 um with satellite scattering angle (ϴ) over the angular range 116°–165°, that is, re increases toward the backscattering direction. Understanding the variations of re with ϴ will require the combined use of theoretical computations along with inter-comparisons of satellite retrievals derived from sensors with dissimilar viewing geometry.
Pathak, Raju; Sahany, Sandeep; Mishra, Saroj KantaPathak, R., S. Sahany, S. K. Mishra, 2021: Impact of Stochastic Entrainment in the NCAR CAM Deep Convection Parameterization on the Simulation of South Asian Summer Monsoon. Climate Dynamics. doi: 10.1007/s00382-021-05870-1. Model simulations are highly sensitive to the formulation of the atmospheric mixing process or entrainment in the deep convective parameterizations used in their atmospheric component. In this paper, we have implemented stochastic entrainment in the deep convection scheme of NCAR CAM5 and analyzed the improvements in model simulation, focusing on the South Asian Summer Monsoon (SASM), as compared to the deterministic entrainment formulation in the default version of the model. Simulations using stochastic entrainment (StochCAM5) outperformed default model simulations (DefCAM5), as inferred from multiple metrics associated with the SASM. StochCAM5 significantly alleviated some of the longstanding SASM biases seen in DefCAM5, such as precipitation pattern and magnitude over the Arabian Sea and western Equatorial Indian ocean, early monsoon withdrawal, and the overestimation in the frequency of light precipitation and the underestimation in the frequency of large-to-extreme precipitation. Related SASM dynamical and thermodynamical features, such as Somali Jet, low-level westerly winds, and meridional tropospheric temperature gradient (MTTG), are improved in StochCAM5. Further, the simulation of monsoon intra-seasonal oscillation (MISO), Madden Julian Oscillation (MJO), and equatorial Kelvin waves are improved in StochCAM5. Many essential climate variables, such as shortwave and longwave cloud forcing, cloud cover, relative and specific humidity, and precipitable water, show significant improvement in StochCAM5.
Payez, Alexandre; Dewitte, Steven; Clerbaux, NicolasPayez, A., S. Dewitte, N. Clerbaux, 2021: Dual View on Clear-Sky Top-of-Atmosphere Albedos from Meteosat Second Generation Satellites. Remote Sensing, 13(9), 1655. doi: 10.3390/rs13091655. Geostationary observations offer the unique opportunity to resolve the diurnal cycle of the Earth’s Radiation Budget at the top of the atmosphere (TOA), crucial for climate-change studies. However, a drawback of the continuous temporal coverage of the geostationary orbit is the fixed viewing geometry. As a consequence, imperfections in the angular distribution models (ADMs) used in the radiance-to-flux conversion process or residual angular-dependent narrowband-to-broadband conversion errors can result in systematic errors of the estimated radiative fluxes. In this work, focusing on clear-sky reflected TOA observations, we compare the overlapping views from Meteosat Second Generation satellites at 0° and 41.5°E longitude which enable a quantification of viewing-angle-dependent differences. Using data derived from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI), we identify some of the main sources of discrepancies, and show that they can be significantly reduced at the level of one month. This is achieved, separately for each satellite, via a masking procedure followed by an empirical fit at the pixel-level that takes into account all the clear-sky data from that satellite, calculated separately per timeslot of the day, over the month of November 2016. The method is then applied to each month of 2017, and gives a quadratic mean of the albedo root-mean squared difference over the dual-view region which is comparable from month to month, with a 2017 average value of 0.01. Sources of discrepancies include the difficulty to estimate the flux over the sunglint ocean region close to the limbs, the fact that the data processing does not include dedicated angular distribution models for the aerosol-over-ocean case, and the existence of an observer-dependent diurnal-asymmetry artefact affecting the clear-sky-albedo dependence on the solar zenith angle particularly over land areas. angular distribution models; SEVIRI; geostationary satellites; top-of-atmosphere albedo; reflected solar radiation; diurnal-asymmetry artefact
Pei, Suyang; Shinoda, Toshiaki; Steffen, John; Seo, HyodaePei, S., T. Shinoda, J. Steffen, H. Seo, 2021: Substantial Sea Surface Temperature Cooling in the Banda Sea Associated With the Madden-Julian Oscillation in the Boreal Winter of 2015. Journal of Geophysical Research: Oceans, 126(6), e2021JC017226. doi: 10.1029/2021JC017226. Substantial (∼2°C) basin averaged sea surface temperature (SST) cooling in the Banda Sea occurred in less than a 14-day period during the 2015 boreal winter Madden-Julian Oscillation (MJO). Such rapid and large cooling associated with the MJO has not been reported at least in the last two decades. Processes that control the substantial cooling during the 2015 MJO event are examined using high-resolution ocean reanalysis and one-dimensional (1-D) ocean model simulations. Previous studies suggest that MJO-induced SST variability in the Banda Sea is primarily controlled by surface heat flux. However, heat budget analysis of the model indicates that entrainment cooling produced by vertical mixing contributes more than surface heat flux for driving the basin-wide SST cooling during the 2015 event. Analysis of the ocean reanalysis further demonstrates that the prominent coastal upwelling around islands in the southern basin occurs near the end of the cooling period. The upwelled cold waters are advected by MJO-induced surface currents to a large area within the Banda Sea, which further maintains the basin-wide cold SST. These results are compared with another MJO-driven substantial cooling event during the boreal winter of 2007 in which the cooling is mostly driven by surface heat flux. Sensitivity experiments, in which initial temperature conditions for the two events are replaced by each other, demonstrate that the elevated thermocline associated with the 2015 strong El Niño is largely responsible for the intensified cooling generated by the vertical mixing with colder subsurface waters. sea surface temperature; Banda Sea; El Niño-Southern Oscillation (ENSO); Madden-Julian Oscillation (MJO); Maritime Continent; mixed layer processes
Peng, Jianghai; Jiang, Bo; Chen, Hongkai; Liang, Shunlin; Liang, Hui; Li, Shaopeng; Han, Jiakun; Liu, Qiang; Cheng, Jie; Yao, Yunjun; Jia, Kun; Zhang, XiaotongPeng, J., B. Jiang, H. Chen, S. Liang, H. Liang, S. Li, J. Han, Q. Liu, J. Cheng, Y. Yao, K. Jia, X. Zhang, 2021: A New Empirical Estimation Scheme for Daily Net Radiation at the Ocean Surface. Remote Sensing, 13(20), 4170. doi: 10.3390/rs13204170. Ocean surface net radiation (Rn) is significant in research on the Earth’s heat balance systems, air–sea interactions, and other applications. However, there have been few studies on Rn until now. Based on radiative and meteorological measurements collected from 66 globally distributed moored buoys, it was found that Rn was dominated by downward shortwave radiation (Rg↓) when the length ratio of daytime (LRD) was greater than 0.4 but dominated by downward longwave radiation (Rl↓) for the other cases (LRD ≤ 0.4). Therefore, an empirical scheme that includes two conditional models named Case 1 (LRD > 0.4) utilizing Rg↓ as a major input and Case 2 (LRD ≤ 0.4) utilizing Rl↓ as a major input for Rn estimation was successfully developed. After validation against in situ Rn, the performance of the empirical scheme was satisfactory with an overall R2 value of 0.972, an RMSE of 9.768 Wm−2, and a bias of −0.092 Wm−2. Specifically, the accuracies of the two conditional models were also very good, with RMSEs of 9.805 and 2.824 Wm−2 and biases of −0.095 and 0.346 Wm−2 for the Case 1 and Case 2 models, respectively. However, due to the limited number of available samples, the performances of these new models were poor in coastal and high-latitude areas, and the models did not work when the LRD was too small (i.e., LRD < 0.3). Overall, the newly developed empirical scheme for Rn estimation has strong potential to be widely used in practical use because of its simple format and high accuracy. CERES; longwave radiation; net radiation; shortwave radiation; buoy data; empirical model; sea surface
Perpina, Miguel; Noel, Vincent; Chepfer, Helene; Guzman, Rodrigo; Feofilov, Artem G.Perpina, M., V. Noel, H. Chepfer, R. Guzman, A. G. Feofilov, 2021: Link Between Opaque Cloud Properties and Atmospheric Dynamics in Observations and Simulations of Current Climate in the Tropics, and Impact on Future Predictions. Journal of Geophysical Research: Atmospheres, 126(17), e2020JD033899. doi: 10.1029/2020JD033899. Using spaceborne lidar observations and reanalyzes (2008–2014), we relate the vertical wind speed at 500 hPa (ω500), indicator of atmospheric circulation, to properties of opaque clouds (altitude and cover) and to the Cloud Radiative Effect (CRE) in the Tropics. We confront those observations with simulations by IPSL-CM6 and CESM1 climate models using early 21st century emissions. Both models overestimate the average opaque cloud cover. IPSL-CM6 puts high opaque clouds too high (+2 km), especially in ascendance. CESM1 overestimates the intermediate opaque cloud cover and underestimates small and large opaque cloud covers. Both models agree that cloud properties behave differently at wind speed above (strong subsidence) or below (weak subsidence and ascendance) 20 hPa/day. In future climate (2089–2095), variables affected by biases in current climate are affected by notable changes: IPSL-CM6 puts high opaque clouds even higher (+2 km) while opaque cloud cover above 30% decreases and below 30% increases in CESM1. Both models predict very little change in the average net CRE in the future. We find that predicted changes of cloud properties can be regionally driven by dynamic or thermodynamic changes, depending on the relationship between opaque cloud altitude and ω500 in the model. Overall, most changes are due to thermodynamic changes in the relationship between cloud property and atmospheric dynamics.
Peters, Ian Marius; Buonassisi, TonioPeters, I. M., T. Buonassisi, 2021: How changes in worldwide operating conditions affect solar cell performance. Solar Energy, 220, 671-679. doi: 10.1016/j.solener.2021.01.017. In field operation, solar cells are exposed to constantly changing operating conditions. These changing conditions have an impact on energy yield. Present-day yield predictions mostly use linear correction coefficients derived from lab experiments. These corrections neglect interactions between meteorological parameters like temperature and humidity. In this study, we reverse this approach by analyzing simulated solar cell performance under varying conditions worldwide. We use meteorological data measured between 2006 and 2015 to establish trends in the development of meteorological conditions and solar cell performance. From these two trends, we obtain linear correlation coefficients. The obtained implied temperature coefficient, on average, has a value of −0.52 ± 0.03%/K. This value is 15% higher than the tabulated temperature coefficient (−0.45%/K) used in the simulation, demonstrating the impact of coinciding meteorological factors. Light absorption due to elevated humidity levels is likely the strongest contributor to the deviation. One application of these findings is a projection of how today's crystalline silicon solar panels would perform due to rising temperature at the end of the 21st century. Using the established implied temperature coefficient, we project performance reductions of between 0.7% and 2.5%, depending on the warming scenario. The effect is reduced in higher efficient, upcoming photovoltaic technologies, providing further motivation to develop and improve these solar cells. Modelling; Performance ratio; Silicon solar cell; Temperature dependence
Pi, Chia-Jung; Chen, Jen-PingPi, C., J. Chen, 2021: Integrated cloud macro- and micro-physics schemes with kinetic treatment of condensation processes for global models. Atmospheric Research, 261, 105745. doi: 10.1016/j.atmosres.2021.105745. A new parameterization scheme was developed to remove the saturation adjustment assumption and resolve the condensation process in the grid-scale cloud macrophysics scheme to build an integrated cloud microphysics scheme for global climate models. By applying a saturation prediction equation with calculations based on cloud hydrometeor properties, supersaturation or subsaturation can be determined within the macrophysics scheme. This treatment provides the basis for condensation calculation and allows the Wegener–Bergeron–Findeisen process to be resolved explicitly to render a realistic liquid–ice partition in mixed-phase clouds. The cloud fraction scheme was modified based on physics principles to complement the condensation scheme. The new scheme's performance was examined by incorporating it into the Community Atmosphere Model version 5 (CAM5) single-column model to simulate a Tropical Warm Pool–International Cloud Experiment (TWP–ICE) case. The results revealed that grid-scale cloud properties are sensitive to the condensation process's treatment, and the new scheme can produce a more reasonable cloud fraction and liquid–ice partition than the original CAM5. The theory-based scheme developed in this study may provide insight for addressing consistency between the macrophysical and microphysical schemes in global climate models. Cloud microphysics; Cloud macrophysics; Liquid-ice partition; Mixed-phase supersaturation; Wegener–Bergeron–Findeisen process
Prijith, S. S.; Lima, C. B.; Ramana, M. V.; Sai, M. V. R. SeshaPrijith, S. S., C. B. Lima, M. V. Ramana, M. V. R. S. Sai, 2021: Intra-seasonal contrasting trends in clouds due to warming induced circulation changes. Scientific Reports, 11(1), 16985. doi: 10.1038/s41598-021-96246-2. Quantification of long term changes in cloud distribution and properties is critical for the proper assessment of future climate. We show contrasting trends in cloud properties and cloud radiative effects over Northwest Indian Ocean (NWIO) in south Asian summer monsoon. Cloud top height (CTH) decreases in June (− 69 ± 3 myr−1) and July (− 44 ± 3 myr−1), whereas it increases in August (106 ± 2 myr−1) and September (37 ± 1 myr−1). These contrasting trends are investigated to be due to the changes in upper tropospheric winds and atmospheric circulation pattern. Strengthening of upper tropospheric easterlies and changes in vertical wind dampen the vertical development of clouds in June and July. In contrast, weakening of upper tropospheric winds over NWIO and strengthening of updraft favour the vertical growth of clouds in August. Further, changes in horizontal winds at 450–350 hPa and strengthening of Indian Ocean Walker cell favour the westward spread of high level clouds, contributing to the increase in CTH over NWIO in August. Decrease of cloud cover and altitude in June and July and increase of the same in subsequent months would affect the monsoon rainfall over the Indian region. Proper representation of these intra-seasonal contrasting trends of clouds in climate models is important for the better prediction of regional weather.
Pu, Wei; Cui, Jiecan; Wu, Dongyou; Shi, Tenglong; Chen, Yang; Xing, Yuxuan; Zhou, Yue; Wang, XinPu, W., J. Cui, D. Wu, T. Shi, Y. Chen, Y. Xing, Y. Zhou, X. Wang, 2021: Unprecedented snow darkening and melting in New Zealand due to 2019–2020 Australian wildfires. Fundamental Research. doi: 10.1016/j.fmre.2021.04.001. Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate; however, their potential effects on the cryosphere are difficult to assess. Catastrophic wildfires in Australia during 2019–2020 emitted large amounts of light-absorbing particles (LAPs) to the atmosphere. Satellite observations indicate that these LAPs caused unprecedented snow-darkening of glaciers in New Zealand through long-range transport and deposition, with their effects lasting for up to three months in January–March 2020, influencing >90% of total glacier/snow and leading to a mean broadband snow-reflectance reduction of 0.08 ± 0.03. This snow darkening accelerated snowmelt by ~0.41 ± 0.2 cm day–1 during the southern summer, equivalent to that caused by a ~1.8 °C increase in air temperature. This indicates the significant impact of the 2019–2020 Australian wildfires on the hydrologic cycle in New Zealand, exceeding that of the local climate warming of ~1.5 °C since the preindustrial period. Wildfire-induced snow darkening is not limited to New Zealand. Future projections of wildfire incidence indicate widespread effects of snow darkening on the global cryosphere. Remote sensing; Australian wildfire; Glacier; Light-absorbing particles; Snow darkening
Raghuraman, Shiv Priyam; Paynter, David; Ramaswamy, V.Raghuraman, S. P., D. Paynter, V. Ramaswamy, 2021: Anthropogenic forcing and response yield observed positive trend in Earth’s energy imbalance. Nature Communications, 12(1), 4577. doi: 10.1038/s41467-021-24544-4. The observed trend in Earth’s energy imbalance (TEEI), a measure of the acceleration of heat uptake by the planet, is a fundamental indicator of perturbations to climate. Satellite observations (2001–2020) reveal a significant positive globally-averaged TEEI of 0.38 ± 0.24 Wm−2decade−1, but the contributing drivers have yet to be understood. Using climate model simulations, we show that it is exceptionally unlikely (
Ren, Tong; Li, Dongchen; Muller, Jake; Yang, PingRen, T., D. Li, J. Muller, P. Yang, 2021: Sensitivity of Radiative Flux Simulations to Ice Cloud Parameterization over the Equatorial Western Pacific Ocean Region. J. Atmos. Sci., 78(8), 2549-2571. doi: 10.1175/JAS-D-21-0017.1. AbstractPrevious studies suggest explanations of the observed cancellation of shortwave (SW) and longwave (LW) cloud radiative effects (CREs) at the top of the atmosphere over tropical oceans where deep convection prevails, such as interactions among cloud microphysics, radiation, and dynamics. However, simulations based on general circulation models (GCMs) show disagreement in terms of the net (SW + LW) CREs over tropical deep convective ocean regions. One of the GCM uncertainty sources is the parameterization of ice cloud bulk optical properties. In this study, a combination of active and passive satellite daytime cloud retrievals is used to study the sensitivity of radiation flux calculations to ice cloud parameterization over the equatorial western Pacific Ocean region. Three ice cloud schemes are tested. The first is a widely used scheme that assumes hexagonal column ice particles. The second scheme treats ice particles as aggregates of surface-roughened hexagonal columns. The third scheme best matches the cloud ice mass–dimension relation in the cloud microphysics scheme by assuming a mixture of two ice particle habits. The results show that the hexagonal-column-based scheme has the weakest SW CRE but strongest LW CRE among the three. In addition, cloud optical thickness and effective radius are used to cluster cold-top single-layer ice clouds into three types, which resemble thin cirrus, detrained anvil clouds, and deep convective cores, respectively. In agreement with previous studies, cloud SW heating overwhelms LW cooling in the upper portion of anvil-like clouds.
Renner, Maik; Kleidon, Axel; Clark, Martyn; Nijssen, Bart; Heidkamp, Marvin; Best, Martin; Abramowitz, GabRenner, M., A. Kleidon, M. Clark, B. Nijssen, M. Heidkamp, M. Best, G. Abramowitz, 2021: How well can land-surface models represent the diurnal cycle of turbulent heat fluxes?. J. Hydrometeor., 22(1), 77-94. doi: 10.1175/JHM-D-20-0034.1. Abstract The diurnal cycle of solar radiation represents the strongest energetic forcing and dominates the exchange of heat and mass of the land surface with the atmosphere. This diurnal heat redistribution represents a core of land-atmosphere coupling that should be accurately represented in Land-Surface Models (LSM) which are critical parts of weather and climate models. We employ a diagnostic model evaluation approach using a signature-based metric which describes the diurnal variation of heat fluxes. The metric is obtained by decomposing the diurnal variation of surface heat fluxes into their direct response and the phase lag to incoming solar radiation. We employ the output of 13 different LSMs driven with meteorological forcing of 20 FLUXNET sites (PLUMBER dataset by Best et al., 2015). All LSMs show a poor representation of the evaporative fraction and thus the diurnal magnitude of the sensible and latent heat ux under cloud-free conditions. In addition, we find that the diurnal phase of both heat fluxes is poorly represented. The best performing model only reproduces 33% of the evaluated evaporative conditions across the sites. The poor performance of the diurnal cycle of turbulent heat exchange appears to be linked to how models solve for the surface energy balance and redistribute heat into the subsurface. We conclude that a systematic evaluation of diurnal signatures is likely to help to improve the simulated diurnal cycle, better represent land-atmosphere interactions and therefore improve simulations of the near-surface climate.
Richards, Benjamin D. G.; Koll, Daniel D. B.; Cronin, Timothy W.Richards, B. D. G., D. D. B. Koll, T. W. Cronin, 2021: Seasonal Loops Between Local Outgoing Longwave Radiation and Surface Temperature. Geophysical Research Letters, 48(17), e2021GL092978. doi: 10.1029/2021GL092978. The relationship between outgoing longwave radiation (OLR) and the surface temperature has a major influence on Earth's climate sensitivity. Studies often assume that this relationship is approximately linear, but it is unclear whether the approximation always holds. Here we show that, on seasonal timescales, clear-sky OLR is a multivalued function of local surface temperature. In many places, the OLR-temperature relationship is better approximated by a loop than a line and we quantify the resulting “OLR loopiness”, that is, how much clear-sky OLR varies between different seasons with the same surface temperature. Based on offline radiative calculations, in the tropics OLR loops are mainly caused by seasonal variations in relative humidity that are out of phase with surface temperature; in the extratropics, OLR loops are mainly due to variations in lapse rates. Our work provides a mechanism through which Earth's climate feedback can differ between seasonal and long-term time scales.
Ridout, James A.; Barton, Neil P.; Janiga, Matthew A.; Reynolds, Carolyn A.; May, Jackie C.; Rowley, Clark; Bishop, Craig H.Ridout, J. A., N. P. Barton, M. A. Janiga, C. A. Reynolds, J. C. May, C. Rowley, C. H. Bishop, 2021: Surface Radiative Flux Bias Reduction through Regionally Varying Cloud Fraction Parameter Nudging in a Global Coupled Forecast System. Journal of Advances in Modeling Earth Systems, (In Press). doi: 10.1029/2019MS002006. Key Points: A method is presented to nudge a cloud fraction parameter in a global coupled forecast system to reduce surface net shortwave flux biases. Results from a series of 45-day test forecasts are presented demonstrating the efficacy of the approach. Further tests are required to determine operational applicability using a suitable near real-time source of surface radiative flux data. cloud parameterization; coupled modelling; parameter adjustment; surface radiation budget
Riihelä, Aku; Bright, Ryan M.; Anttila, KatiRiihelä, A., R. M. Bright, K. Anttila, 2021: Recent strengthening of snow and ice albedo feedback driven by Antarctic sea-ice loss. Nature Geoscience, 14(11), 832-836. doi: 10.1038/s41561-021-00841-x. The decline of the Arctic cryosphere during recent decades has lowered the region’s surface albedo, reducing its ability to reflect solar radiation back to space. It is not clear what role the Antarctic cryosphere plays in this regard, but new remote-sensing-based techniques and datasets have recently opened the possibility to investigate its role. Here, we leverage these to show that the surface albedo reductions from sustained post-2000 losses in Arctic snow and ice cover equate to increasingly positive snow and ice albedo feedback relative to a 1982–1991 baseline period, with a decadal trend of +0.08 ± 0.04 W m–2 decade–1 between 1992 and 2015. During the same period, the expansion of the Antarctic sea-ice pack generated a negative feedback, with a decadal trend of −0.06 ± 0.02 W m–2 decade–1. However, substantial Antarctic sea-ice losses during 2016–2018 completely reversed the trend, increasing the three-year mean combined Arctic and Antarctic snow and ice albedo feedback to +0.26 ± 0.15 W m–2. This reversal highlights the importance of Antarctic sea-ice loss to the global snow and ice albedo feedback. The 1992–2018 mean feedback is equivalent to approximately 10% of anthropogenic CO2 emissions over the same period; the share may rise markedly should 2016–2018 snow and ice conditions become common, although increasing long-wave emissions will probably mediate the impact on the total radiative-energy budget. Climate-change impacts; Cryospheric science
Roy, Kumar; Mukhopadhyay, Parthasarathi; Krishna, R. P. M.; Khouider, B.; Goswami, B. B.Roy, K., P. Mukhopadhyay, R. P. M. Krishna, B. Khouider, B. B. Goswami, 2021: Evaluation of Mean State in NCEP Climate Forecast System (Version 2) Simulation Using a Stochastic Multicloud Model Calibrated With DYNAMO RADAR Data. Earth and Space Science, 8(8), e2020EA001455. doi: 10.1029/2020EA001455. Stochastic parameterizations are continuously providing promising simulations of unresolved atmospheric processes for global climate models (GCMs). One of the stochastic multi-cloud model (SMCM) features is to mimic the life cycle of the three most common cloud types (congestus, deep, and stratiform) in tropical convective systems. To better represent organized convection in the Climate Forecast System version 2 (CFSv2), the SMCM parameterization is adopted in CFSv2 (SMCM-CTRL) in lieu of the pre-existing revised simplified Arakawa–Schubert (RSAS) cumulus scheme and has shown essential improvements in different large-scale features of tropical convection. But the sensitivity of the SMCM parameterization from the observations is yet to be ascertained. Radar data during the Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign is used to tune the SMCM in the present manuscript. The DYNAMO radar observations have been used to calibrate the SMCM using a Bayesian inference procedure to generate key time scale parameters for the transition probabilities of the underlying Markov chains of the SMCM as implemented in CFS (hereafter SMCM-DYNAMO). SMCM-DYNAMO improves many aspects of the mean state climate compared to RSAS, and SMCM-CTRL. Significant improvement is noted in the rainfall probability distribution function over the global tropics. The global distribution of different types of clouds, particularly low-level clouds, is also improved. The convective and large-scale rainfall simulations are investigated in detail. Atmospheric mean state; DYNAMO constrained SMCM used in CFSv2; DYNAMO RADAR data for constraining the SMCM; stochastic multi-cloud model
Rybka, Harald; Burkhardt, Ulrike; Köhler, Martin; Arka, Ioanna; Bugliaro, Luca; Görsdorf, Ulrich; Horváth, Ákos; Meyer, Catrin I.; Reichardt, Jens; Seifert, Axel; Strandgren, JohanRybka, H., U. Burkhardt, M. Köhler, I. Arka, L. Bugliaro, U. Görsdorf, Á. Horváth, C. I. Meyer, J. Reichardt, A. Seifert, J. Strandgren, 2021: The behavior of high-CAPE (convective available potential energy) summer convection in large-domain large-eddy simulations with ICON. Atmospheric Chemistry and Physics, 21(6), 4285-4318. doi: 10.5194/acp-21-4285-2021. Abstract. Current state-of-the-art regional numerical weather prediction (NWP) models employ kilometer-scale horizontal grid resolutions, thereby simulating convection within the grey zone. Increasing resolution leads to resolving the 3D motion field and has been shown to improve the representation of clouds and precipitation. Using a hectometer-scale model in forecasting mode on a large domain therefore offers a chance to study processes that require the simulation of the 3D motion field at small horizontal scales, such as deep summertime moist convection, a notorious problem in NWP. We use the ICOsahedral Nonhydrostatic weather and climate model in large-eddy simulation mode (ICON-LEM) to simulate deep moist convection and distinguish between scattered, large-scale dynamically forced, and frontal convection. We use different ground- and satellite-based observational data sets, which supply information on ice water content and path, ice cloud cover, and cloud-top height on a similar scale as the simulations, in order to evaluate and constrain our model simulations. We find that the timing and geometric extent of the convectively generated cloud shield agree well with observations, while the lifetime of the convective anvil was, at least in one case, significantly overestimated. Given the large uncertainties of individual ice water path observations, we use a suite of observations in order to better constrain the simulations. ICON-LEM simulates a cloud ice water path that lies between the different observational data sets, but simulations appear to be biased towards a large frozen water path (all frozen hydrometeors). Modifications of parameters within the microphysical scheme have little effect on the bias in the frozen water path and the longevity of the anvil. In particular, one of our convective days appeared to be very sensitive to the initial and boundary conditions, which had a large impact on the convective triggering but little impact on the high frozen water path and long anvil lifetime bias. Based on this limited set of sensitivity experiments, the evolution of locally forced convection appears to depend more on the uncertainty of the large-scale dynamical state based on data assimilation than of microphysical parameters. Overall, we judge ICON-LEM simulations of deep moist convection to be very close to observations regarding the timing, geometrical structure, and cloud ice water path of the convective anvil, but other frozen hydrometeors, in particular graupel, are likely overestimated. Therefore, ICON-LEM supplies important information for weather forecasting and forms a good basis for parameterization development based on physical processes or machine learning.
Sato, Kazutoshi; Inoue, JunSato, K., J. Inoue, 2021: Seasonal Change in Satellite-Retrieved Lower-Tropospheric Ice-Cloud Fraction Over the Southern Ocean. Geophysical Research Letters, 48(23), e2021GL095295. doi: 10.1029/2021GL095295. This study investigated the temperature and fraction of lower-tropospheric ice cloud over Antarctica and the Southern Ocean (SO) using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite data. Over the SO, the maximum low-level ice-cloud fraction below 2 km is observed at cold temperatures (−7.5°C (>−17.5°C) during summer (winter). High fractions of low-level ice cloud observed at higher temperatures over near-coastal Antarctic sea ice areas in summer, coincident with the highest chlorophyll-a concentrations, and over coastal Antarctic ice-covered areas in winter, suggest that marine aerosols act as ice-nucleating particles for ice-cloud formation during summer and winter. ice cloud; Antarctica; CALIPSO; Southern Ocean; chlorophyll
Schuddeboom, A. J.; McDonald, A. J.Schuddeboom, A. J., A. J. McDonald, 2021: The Southern Ocean Radiative Bias, Cloud Compensating Errors, and Equilibrium Climate Sensitivity in CMIP6 Models. Journal of Geophysical Research: Atmospheres, 126(22), e2021JD035310. doi: 10.1029/2021JD035310. Coupled Model Intercomparison Project Phase 6 (CMIP6) models are analyzed using an established cloud clustering methodology. This enables a comparison of cloud representation in models and observations. The simulation of stratocumulus clouds over the Southern Ocean is shown to have changed substantially from earlier generation models. The CMIP6 models analyzed show stratocumulus clouds now occur more often in simulations than in International Satellite Cloud Climatology Project (ISCCP) observations, but are not bright enough compared to Clouds and the Earth's Radiant Energy System (CERES) data. This is in contrast to the “too few, too bright” problem, which has characterized prior model simulations of stratocumulus clouds, particularly over the Southern Ocean. The cloud clusters also enable the calculation of mean and compensating shortwave cloud radiative effect (SW CRE) errors from model data. The compensating errors are shown to be much larger than mean errors suggesting the CMIP6 models still have much to improve in their cloud representation. A statistically significant negative relationship between the mean and compensating errors in SW CRE over the Southern Ocean is identified. This relationship is observed elsewhere, but is only significant over the Southern Ocean. This implies model tuning efforts are hiding biases in the representation of clouds in this region. CMIP6 models have been shown to have a higher equilibrium climate sensitivity (ECS) relative to CMIP5 simulations. The link between ECS and SW CRE mean and compensating errors is investigated but no evidence of a relationship between these variables was found. Southern Ocean; CMIP6; cloud radiative bias; compensating errors; ECS; model comparison
Shen, Lixing; Zhao, Chuanfeng; Yang, XingchuanShen, L., C. Zhao, X. Yang, 2021: Insight Into the Seasonal Variations of the Sea-Land Breeze in Los Angeles With Respect to the Effects of Solar Radiation and Climate Type. Journal of Geophysical Research: Atmospheres, 126(6), e2020JD033197. doi: https://doi.org/10.1029/2020JD033197. This study uses 20 years of observation data to analyze the long-term trend of the sea-land breeze (SLB) in the city of Los Angeles. The focus of the study is on the seasonal variation of the SLB and the main influencing factors both regionally and at a large scale. A new method which is suitable for automatic processing is introduced to analyze the SLB and determine the specific characteristics of the local SLB. The results show the sea wind speed has an obvious seasonal variation with peak value in summer and minimum value in winter. Note the sea wind speed is generally positively related to the in situ solar radiation. In contrast, the seasonal variation of the land wind speed is much weaker. Two main factors are responsible for this phenomenon. First, the response of the temperature difference between land and sea (TDLS) to the season is much more insensitive during nighttime than during daytime, and the TDLS is the direct driver of SLB. Second, the magnitude of the upper layer westerlies has an obvious seasonal variation under the local climate background, which is called the Mediterranean climate. During winter, the stronger upper westerlies enhance the land wind circulation, which further offsets the seasonal gap, and this even causes the fact that there is no corresponding relationship between the season and wind speed. In contrast, the seasonal variation of the westerlies has little effect on the sea wind speed, and the in situ solar radiation remains the determinant factor. solar radiation; Mediterranean climate; sea-land breeze; westerlies
Shen, Pengke; Zhao, Shuqing; Ma, YongjingShen, P., S. Zhao, Y. Ma, 2021: Perturbation of Urbanization to Earth's Surface Energy Balance. Journal of Geophysical Research: Atmospheres, 126(8), e2020JD033521. doi: https://doi.org/10.1029/2020JD033521. Urbanization, one of the most dramatic forms of land conversion, modifies local climatic environments and threatens human life and health. Here we use the space-for-time approach combined with satellite data to quantify the potential perturbation of surface energy balance and land surface temperature (LST) caused by urbanization at global scale. We estimate that collectively +2.4°C, +0.9°C, and +1.7°C potential changes for annual daytime, nighttime, and mean LST could be triggered when land surface converted from natural area to urban use, due primarily to the decline of latent heat during months from April to October (−23.9–−3.2 W m−2), and the reduced sensible heat and ground heat storage in other months (−5.2–−2.4 W m−2). Urbanization perturbation to surface energy balance and temperature exhibit conspicuous spatial heterogeneity (i.e., varying with latitude and climate zones) and temporal asymmetries (i.e., diurnal and seasonal: strong in summer daytime and weak in winter nighttime). These spatial-temporal variations are interrelated closely with local background climate-vegetation regimes, as indicated by strong correlations between urbanization perturbation to surface biophysical effects and precipitation, temperature, vegetation index across regions and months. Our findings provide empirical evidence that biophysical mechanisms of urbanization need to be considered in predicting future trajectories of climate change and local susceptibility of surface energy balance should be accounted for when evaluating urbanization effects and mitigating urban heat. land surface temperature; surface energy balance; background climate; global change; urbanization
Shi, Hongrong; Zhang, Jinqiang; Zhao, Bin; Xia, Xiangao; Hu, Bo; Chen, Hongbin; Wei, Jing; Liu, Mengqi; Bian, Yuxuan; Fu, Disong; Gu, Yu; Liou, Kuo-NanShi, H., J. Zhang, B. Zhao, X. Xia, B. Hu, H. Chen, J. Wei, M. Liu, Y. Bian, D. Fu, Y. Gu, K. Liou, 2021: Surface Brightening in Eastern and Central China Since the Implementation of the Clean Air Action in 2013: Causes and Implications. Geophysical Research Letters, 48(3), e2020GL091105. doi: https://doi.org/10.1029/2020GL091105. Surface brightening has been observed in China since 2005. However, it remains unclear whether the brightening has accelerated recently in response to the strictest ever air pollution control policies since 2013. By combining intensive surface and satellite observations, we find an unprecedented rapid increasing trend in surface solar radiation (SSR) of 0.70–1.16 W m−2 yr−1 over the eastern and central China for 2014–2019. Using a novel method to identify the relative contributions of aerosol and cloud radiative effects to the SSR trends, we find that the strongly declining aerosol radiative effect due to the strict air pollution controls is the main cause of the upward SSR trends; cloud variations should not be the main reason. Distinction exists in seasonal trends of SSR, with decreasing trends in winter and increasing trends in other seasons. Air pollution controls play an important role in regulating SSR, which has valuable implications for photovoltaic power generation. aerosol radiative effect; air pollutant control; eastern and central China; surface solar radiation brightening
Si, Yuwen; Wang, Hongqiang; Wang, Yujia; Yang, Honghai; Chen, Yonghang; Liu, Qiong; Chen, Shuyi; Zheng, NingSi, Y., H. Wang, Y. Wang, H. Yang, Y. Chen, Q. Liu, S. Chen, N. Zheng, 2021: Effects of single-layer low clouds on the surface solar radiation in East Asia. Solar Energy, 224, 1099-1106. doi: 10.1016/j.solener.2021.06.047. The earth surface solar radiation is largely influenced by the physical properties of low clouds, which need to be investigated for effectively utilizing the solar energy. In this paper, four different regions in East Asia were selected and NASA CERES (Clouds and the Earth's Radiant Energy System) SSF (Single Satellite Footprint) Aqua Edition 3A data from the year 2003 to 2016 were used to analyze the annual and inter-annual variations in the low cloud coverage, ice water path and liquid water path of the single-layer low clouds. Results showed that these three physical property parameters achieved their maximums in December or January for most regions. For the past 14 years, both the low cloud coverage and liquid water path achieved their highest multi-year averages and largest fluctuation ranges in the southern region, while the ice water path achieved its highest multi-year average and largest fluctuation range in the northwestern region. The cooling effect of single-layer low clouds on the solar radiation depended on the regions and seasons. For the past 14 years, the cooling effect of single-layer low clouds showed an overall weakening tendency in the northwestern region, but an overall strengthening tendency in the other three regions, and especially, in the southern region. Regarding the correlation to the surface shortwave radiation, the liquid water path was a closer factor for most regions, while the ice water path was an insignificant factor, especially in the northwestern region. East Asia; Cloud physical properties; Shortwave radiative forcing; Single-layer low clouds
Sledd, A.; L’Ecuyer, T. S.Sledd, A., T. S. L’Ecuyer, 2021: Emerging Trends in Arctic Solar Absorption. Geophysical Research Letters, 48(24), e2021GL095813. doi: 10.1029/2021GL095813. Recent satellite observations confirm that the Arctic is absorbing more solar radiation now than at the start of this century in response to declining Arctic sea ice and snow covers. Trends in the solar radiation input to Arctic ocean and land surfaces now each exceed interannual variability at the 95% confidence level, although all-sky trends have taken 20%–40% longer to emerge compared to clear-sky conditions. Clouds reduce mean solar absorption and secular trends over both land and ocean, but the effect of clouds on natural variability depends on the underlying surface. While clouds increase the time needed to unambiguously identify trends in nearly all Arctic regions, their masking effects are strongest over oceans. Clouds have extended the time to emergence of already observed clear-sky trends beyond the existing 21 years Clouds and Earth's Radiant Energy System record in half of eight Arctic seas, supporting the need for continued satellite-based radiative flux observations over the Arctic. clouds; climate change; Arctic; solar radiation; trend detection
Sledd, Anne; L'Ecuyer, TristanSledd, A., T. L'Ecuyer, 2021: Uncertainty in Forced and Natural Arctic Solar Absorption Variations in CMIP6 Models. J. Climate, 34(3), 931-948. doi: 10.1175/JCLI-D-20-0244.1.
Su, Wenying; Liang, Lusheng; Myhre, Gunnar; Thorsen, Tyler J.; Loeb, Norman G.; Schuster, Gregory L.; Ginoux, Paul; Paulot, Fabien; Neubauer, David; Checa-Garcia, Ramiro; Matsui, Hitoshi; Tsigaridis, Kostas; Skeie, Ragnhild B.; Takemura, Toshihiko; Bauer, Susanne E.; Schulz, MichaelSu, W., L. Liang, G. Myhre, T. J. Thorsen, N. G. Loeb, G. L. Schuster, P. Ginoux, F. Paulot, D. Neubauer, R. Checa-Garcia, H. Matsui, K. Tsigaridis, R. B. Skeie, T. Takemura, S. E. Bauer, M. Schulz, 2021: Understanding Top-of-Atmosphere Flux Bias in the AeroCom Phase III Models: A Clear-Sky Perspective. Journal of Advances in Modeling Earth Systems, 13(9), e2021MS002584. doi: 10.1029/2021MS002584. Biases in aerosol optical depths (AOD) and land surface albedos in the AeroCom models are manifested in the top-of-atmosphere (TOA) clear-sky reflected shortwave (SW) fluxes. Biases in the SW fluxes from AeroCom models are quantitatively related to biases in AOD and land surface albedo by using their radiative kernels. Over ocean, AOD contributes about 25% to the S–N mean SW flux bias for the multi-model mean (MMM) result. Over land, AOD and land surface albedo contribute about 40% and 30%, respectively, to the S–N mean SW flux bias for the MMM result. Furthermore, the spatial patterns of the SW flux biases derived from the radiative kernels are very similar to those between models and CERES observation, with the correlation coefficient of 0.6 over ocean and 0.76 over land for MMM using data of 2010. Satellite data used in this evaluation are derived independently from each other, consistencies in their bias patterns when compared with model simulations suggest that these patterns are robust. This highlights the importance of evaluating related variables in a synergistic manner to provide an unambiguous assessment of the models, as results from single parameter assessments are often confounded by measurement uncertainty. Model biases in land surface albedos can and must be corrected to accurately calculate TOA flux. We also compare the AOD trend from three models with the observation-based counterpart. These models reproduce all notable trends in AOD except the decreasing trend over eastern China and the adjacent oceanic regions due to limitations in the emission data set. aerosols; radiative flux; surface albedo
Sullivan, Sylvia C.; Voigt, AikoSullivan, S. C., A. Voigt, 2021: Ice microphysical processes exert a strong control on the simulated radiative energy budget in the tropics. Communications Earth & Environment, 2(1), 1-8. doi: 10.1038/s43247-021-00206-7. Simulations of the global climate system at storm-resolving resolutions of 2 km are now becoming feasible and show promising realism in clouds and precipitation. However, shortcomings in their representation of microscale processes, like the interaction of cloud droplets and ice crystals with radiation, can still restrict their utility. Here, we illustrate how changes to the ice microphysics scheme dramatically alter both the vertical profile of cloud-radiative heating and top-of-atmosphere outgoing longwave radiation (terrestrial infrared cooling) in storm-resolving simulations over the Asian monsoon region. Poorly-constrained parameters in the ice nucleation scheme, overactive conversion of ice to snow, and inconsistent treatment of ice crystal effective radius between microphysics and radiation alter cloud-radiative heating by a factor of four and domain-mean infrared cooling by 30 W m−2. Vertical resolution, on the other hand, has a very limited impact. Even in state-of-the-art models then, uncertainties in microscale cloud properties exert a strong control on the radiative budget that propagates to both atmospheric circulation and regional climate. These uncertainties need to be reduced to realize the full potential of storm-resolving models.
Suselj, Kay; Teixeira, Joao; Kurowski, Marcin J.; Molod, AndreaSuselj, K., J. Teixeira, M. J. Kurowski, A. Molod, 2021: Improving the Representation of Subtropical Boundary Layer Clouds in the NASA GEOS Model with the Eddy-Diffusivity/Mass-Flux Parameterization. Mon. Wea. Rev., 149(3), 793-809. doi: 10.1175/MWR-D-20-0183.1. AbstractA systematic underestimation of subtropical planetary boundary layer (PBL) stratocumulus clouds by the GEOS model has been significantly improved by a new eddy-diffusivity/mass-flux (EDMF) parameterization. The EDMF parameterization represents the subgrid-scale transport in the dry and moist parts of the PBL in a unified manner and it combines an adjusted eddy-diffusivity PBL scheme from GEOS with a stochastic multiplume mass-flux model. The new EDMF version of the GEOS model is first compared against the CONTROL version in a single-column model (SCM) framework for two benchmark cases representing subtropical stratocumulus and shallow cumulus clouds, and validated against large-eddy simulations. Global simulations are performed and compared against observations and reanalysis data. The results show that the EDMF version of the GEOS model produces more realistic subtropical PBL clouds. The EDMF improvements first detected in the SCM framework translate into similar improvements of the global GEOS model.
Svensmark, Henrik; Svensmark, Jacob; Enghoff, Martin Bødker; Shaviv, Nir J.Svensmark, H., J. Svensmark, M. B. Enghoff, N. J. Shaviv, 2021: Atmospheric ionization and cloud radiative forcing. Scientific Reports, 11(1), 19668. doi: 10.1038/s41598-021-99033-1. Atmospheric ionization produced by cosmic rays has been suspected to influence aerosols and clouds, but its actual importance has been questioned. If changes in atmospheric ionization have a substantial impact on clouds, one would expect to observe significant responses in Earth’s energy budget. Here it is shown that the average of the five strongest week-long decreases in atmospheric ionization coincides with changes in the average net radiative balance of 1.7 W/m$$^2$$(median value: 1.2 W/m$$^2$$) using CERES satellite observations. Simultaneous satellite observations of clouds show that these variations are mainly caused by changes in the short-wave radiation of low liquid clouds along with small changes in the long-wave radiation, and are almost exclusively located over the pristine areas of the oceans. These observed radiation and cloud changes are consistent with a link in which atmospheric ionization modulates aerosol's formation and growth, which survive to cloud condensation nuclei and ultimately affect cloud formation and thereby temporarily the radiative balance of Earth. Astronomy and planetary science; Climate sciences
Takahashi, Naoya; Hayasaka, Tadahiro; Qiu, Bo; Yamaguchi, RyoheiTakahashi, N., T. Hayasaka, B. Qiu, R. Yamaguchi, 2021: Observed response of marine boundary layer cloud to the interannual variations of summertime Oyashio extension SST front. Climate Dynamics. doi: 10.1007/s00382-021-05649-4. Active roles of both sea surface temperature (SST) and its frontal characteristics to the atmosphere in the mid-latitudes have been investigated around the western boundary current regions, and most studies have focused on winter season. The present study investigated the influence of the variation of the summertime Oyashio extension SST front (SSTF) in modulating low-level cloud properties (i.e., low-level cloud cover [LCC], cloud optical thickness [COT], and shortwave cloud radiative effect [SWCRE]) on inter-annual timescales, based on available satellite and Argo float datasets during 2003–2016. First, we examined the mechanism of summertime SSTF variability itself. The strength of the SSTF (SSSTF), defined as the maximum horizontal gradient of SST, has clear inter-annual variations. Frontogenesis equation analysis and regression analysis for subsurface temperature indicated that the inter-annual variations of the summertime SSSTF in the western North Pacific are closely related to the variations of not surface heat flux, but western boundary currents, particularly the Oyashio Extensions. The response of low-level cloud to intensified SSSTF is that negative SWCRE with positive COT anomaly in the northern flank of the SSTF can be induced by cold SST anomalies. The spatial scale of the low-level cloud response was larger than the SST frontal scale, and the spatial distribution of the response was mainly constrained by the pathways of Kuroshio and Oyashio Extensions. Multi-linear regression analysis revealed that the local SST anomaly played largest role in modulating the SWCRE and COT anomalies among the cloud controlling factors (e.g., estimated inversion strength, air-temperature advection) accounting for more than 50% of the variation. This study provides an observational evidence of the active role of local SST anomalies in summertime associated with the western boundary currents to the oceanic low-level cloud.
Takahashi, Naoya; Richards, Kelvin J.; Schneider, Niklas; Annamalai, H.; Hsu, Wei-Ching; Nonaka, MasamiTakahashi, N., K. J. Richards, N. Schneider, H. Annamalai, W. Hsu, M. Nonaka, 2021: Formation Mechanism of Warm SST Anomalies in 2010s Around Hawaii. Journal of Geophysical Research: Oceans, 126(11), e2021JC017763. doi: 10.1029/2021JC017763. Warm sea surface temperature (SST) anomalies have been observed in the subtropical North Pacific around Hawaii in the recent decade, appearing from 2013. We examined the formation mechanisms of the warm SST anomalies in terms of relative contribution of atmospheric surface forcing and oceanic dynamics, using the latest reanalysis products from ECMWF (ERA5 for atmosphere and ORAS5 for ocean). Results of the mixed layer temperature budget diagnosis in the target area (10–20°N and 180°–160°W) indicates that contributions from anomalous latent heat fluxes to the subtropical SST anomalies are dominant. Oceanic advective contributions play a secondary role, dampen the SST anomalies, and are negatively correlated (r = −0.38) with the latent heat fluxes. For example, the +1.0 K SST increased from 2011 to 2015 results from +1.5 K contributions from sum of surface heat flux and −0.5 K from meridional oceanic advection. The anti-correlation between atmospheric forcing and oceanic meridional advection reflects co-variations of wind-driven latent heat flux and meridional Ekman advection due to the weakening of the zonal component of the surface winds.
Talib, Joshua; Taylor, Christopher M.; Duan, Anmin; Turner, Andrew G.Talib, J., C. M. Taylor, A. Duan, A. G. Turner, 2021: Intraseasonal soil moisture-atmosphere feedbacks on the Tibetan Plateau circulation. J. Climate, (In Press). doi: 10.1175/JCLI-D-20-0377.1.
Tang, Wenjun; Qin, Jun; Yang, Kun; Zhu, Fuxin; Zhou, XuTang, W., J. Qin, K. Yang, F. Zhu, X. Zhou, 2021: Does ERA5 outperform satellite products in estimating atmospheric downward longwave radiation at the surface?. Atmospheric Research, 252, 105453. doi: 10.1016/j.atmosres.2021.105453. Atmospheric downward longwave radiation (DLR) is a key component of the surface energy budget in the Earth system. Satellite retrievals and atmospheric reanalysis estimates are the two typical approaches to obtaining a spatio-temporally continuous DLR product. In this study, we evaluated the DLR product from the latest ERA5 atmospheric reanalysis and the well-known Clouds and Earth's Radiant Energy System (CERES) satellite retrievals, against high-quality observations collected at 46 Baseline Surface Radiation Network (BSRN) stations over land surfaces and at 9 Global Tropical Moored Buoy Array (GTMBA) buoy stations. The accuracy of the ERA5 DLR product over land was found to be higher on average than that of CERES at hourly to monthly time scales. Conversely, ERA5 performed slightly worse than CERES-SYN when estimating DLR over the ocean surface. This is the first time that atmospheric reanalysis has performed better than satellite retrievals in estimating DLR over the land surface, demonstrating the potentially extensive application prospects for ERA5 as well as setting new challenges for quantitative remote sensing research. CERES; ERA5; Accuracy; Evaluation; Longwave radiation
Tang, Wenjun; Yang, Kun; Qin, Jun; Li, Jun; Ye, JiangangTang, W., K. Yang, J. Qin, J. Li, J. Ye, 2021: How Accurate Are Satellite-Derived Surface Solar Radiation Products over Tropical Oceans?. J. Atmos. Oceanic Technol., 38(2), 283-291. doi: 10.1175/JTECH-D-20-0099.1. AbstractSurface solar radiation (SSR) over the ocean is essential for studies of ocean–atmosphere interactions and marine ecology, and satellite remote sensing is a major way to obtain the SSR over ocean. A new high-resolution (10 km; 3 h) SSR product has recently been developed, mainly based on the newly released cloud product of the International Satellite Cloud Climatology Project H series (ISCCP-HXG), and is available for the period from July 1983 to December 2018. In this study, we compared this SSR product with in situ observations from 70 buoy sites in the Global Tropical Moored Buoy Array (GTMBA) and also compared it with another well-known satellite-derived SSR product from the Clouds and the Earth’s Radiant Energy System (CERES; edition 4.1), which has a spatial resolution of approximately 100 km. The results show that the ISCCP-HXG SSR product is generally more accurate than the CERES SSR product for both ocean and land surfaces. We also found that the accuracy of both satellite-derived SSR products (ISCCP-HXG and CRERS) was higher over ocean than over land and that the accuracy of ISCCP-HXG SSR improves greatly when the spatial resolution of the product is coarsened to ≥ 30 km.
Tselioudis, George; Rossow, William B.; Jakob, Christian; Remillard, Jasmine; Tropf, Derek; Zhang, YuanchongTselioudis, G., W. B. Rossow, C. Jakob, J. Remillard, D. Tropf, Y. Zhang, 2021: Evaluation of Clouds, Radiation, and Precipitation in CMIP6 Models Using Global Weather States Derived from ISCCP-H Cloud Property Data. J. Climate, 34(17), 7311-7324. doi: 10.1175/JCLI-D-21-0076.1. AbstractA clustering methodology is applied to cloud optical depth (τ)–cloud top pressure (TAU-PC) histograms from the new 1° resolution ISCCP-H dataset to derive an updated global weather state (WS) dataset. Then, TAU-PC histograms from current-climate CMIP6 model simulations are assigned to the ISCCP-H WSs along with their concurrent radiation and precipitation properties to evaluate model cloud, radiation, and precipitation properties in the context of the weather states. The new ISCCP-H analysis produces WSs that are very similar to those previously found in the lower-resolution ISCCP-D dataset. The main difference lies in the splitting of the ISCCP-D thin stratocumulus WS between the ISCCP-H shallow cumulus and stratocumulus WSs, which results in the reduction by one of the total WS number. The evaluation of the CMIP6 models against the ISCCP-H weather states shows that, in the ensemble mean, the models are producing an adequate representation of the frequency and geographical distribution of the WSs, with measurable improvements compared to the WSs derived for the CMIP5 ensemble. However, the frequency of shallow cumulus clouds continues to be underestimated, and, in some WSs the good agreement of the ensemble mean with observations comes from averaging models that significantly overpredict and underpredict the ISCCP-H WS frequency. In addition, significant biases exist in the internal cloud properties of the model WSs, such as the model underestimation of cloud fraction in middle-top clouds and secondarily in midlatitude storm and stratocumulus clouds, that result in an underestimation of cloud SW cooling in those regimes.
Tucker, Simon O.; Kendon, Elizabeth J.; Bellouin, Nicolas; Buonomo, Erasmo; Johnson, Ben; Murphy, James M.Tucker, S. O., E. J. Kendon, N. Bellouin, E. Buonomo, B. Johnson, J. M. Murphy, 2021: Evaluation of a new 12 km regional perturbed parameter ensemble over Europe. Climate Dynamics. doi: 10.1007/s00382-021-05941-3. We evaluate a 12-member perturbed parameter ensemble of regional climate simulations over Europe at 12 km resolution, carried out as part of the UK Climate Projections (UKCP) project. This ensemble is formed by varying uncertain parameters within the model physics, allowing uncertainty in future projections due to climate modelling uncertainty to be explored in a systematic way. We focus on present day performance both compared to observations, and consistency with the driving global ensemble. Daily and seasonal temperature and precipitation are evaluated as two variables commonly used in impacts assessments. For precipitation we find that downscaling, even whilst within the convection-parameterised regime, generally improves daily precipitation, but not everywhere. In summer, the underestimation of dry day frequency is worse in the regional ensemble than in the driving simulations. For temperature we find that the regional ensemble inherits a large wintertime cold bias from the global model, however downscaling reduces this bias. The largest bias reduction is in daily winter cold temperature extremes. In summer the regional ensemble is cooler and wetter than the driving global models, and we examine cloud and radiation diagnostics to understand the causes of the differences. We also use a low-resolution regional simulation to determine whether the differences are a consequence of resolution, or due to other configuration differences, with the predominant configuration difference being the treatment of aerosols. We find that use of the EasyAerosol scheme in the regional model, which aims to approximate the aerosol effects in the driving model, causes reduced temperatures by around 0.5 K over Eastern Europe in Summer, and warming of a similar magnitude over France and Germany in Winter, relative to the impact of interactive aerosol in the global runs. Precipitation is also increased in these regions. Overall, we find that the regional model is consistent with the global model, but with a typically better representation of daily extremes and consequently we have higher confidence in its projections of their future change.
Uribe, M. R.; Sierra, C. A.; Dukes, J. S.Uribe, M. R., C. A. Sierra, J. S. Dukes, 2021: Seasonality of Tropical Photosynthesis: A Pantropical Map of Correlations With Precipitation and Radiation and Comparison to Model Outputs. Journal of Geophysical Research: Biogeosciences, 126(11), e2020JG006123. doi: 10.1029/2020JG006123. Tropical ecosystems strongly influence Earth's climate and weather patterns. Most tropical ecosystems remain warm year-round; nonetheless, their plants undergo seasonal cycles of carbon and water exchange. Previous research has shown the importance of precipitation and radiation as drivers of the seasonality of photosynthetic activity in the tropics. Although data are scarce, field-based studies have found that seasonal cycles at a handful of tropical sites do not match those in the land surface model (LSM) simulations. A comprehensive understanding and model comparison of how seasonal variations in tropical photosynthetic activity relate to climate is lacking. Here, we identify the relationships of precipitation and radiation with satellite-based proxies for photosynthetic activity (e.g., GOME-2 SIF, MAIAC EVI) for the pantropical region. Three dominant and spatially distinct seasonal relationships emerge: photosynthetic activity that is positively correlated with both drivers (36% of tropical pixels), activity that increases following rain but decreases with radiation (28%), and activity that increases following bright seasons but decreases with rain (14%). We compare distributions of these observed relationships with those from LSMs. In general, compared to satellite-based proxies of photosynthetic activity, model simulations of gross primary productivity (GPP) overestimate the extent of positive correlations of photosynthetic activity with water and underestimate positive correlations with radiation. The largest discrepancies between simulations and observations are in the representation of regions where photosynthetic activity increases with radiation and decreases with rain. Our clear scheme for representing the relationship between climate and photosynthetic activity can be used to benchmark tropical seasonality of GPP in LSMs. climate; seasonality; models; photosynthetic activity; solar induced fluorescence; tropical ecosystems
Valdivieso, Maria; Peatman, Simon C.; Klingaman, Nicholas P.Valdivieso, M., S. C. Peatman, N. P. Klingaman, 2021: The influence of air-sea coupling on forecasts of the 2016 Indian summer monsoon and its intraseasonal variability. Quarterly Journal of the Royal Meteorological Society, (In Press). doi: 10.1002/qj.3914. Daily initialized coupled and uncoupled numerical weather prediction (NWP) forecasts from the global Met Office Unified Model (MetUM) are compared for the 2016 Indian summer monsoon. Three MetUM configurations are used: atmosphere-only (ATM), coupled to a mixed-layer ocean model (KPP), and coupled to a dynamical ocean model (NEMO). The analysis focuses on the impact of air-sea coupling, particularly in the Bay of Bengal (BoB), on NWP for monsoon rainfall. Seasonal-mean biases in all three configurations are highly consistent and driven by errors in atmospheric processes. Rainfall is initially overestimated over India, but underestimated over the BoB, the latter associated with too much shortwave radiation and too little cloud cover in MetUM. The excess shortwave radiation (>40 Wm -2 over the northwest BoB) is partially compensated by additional latent cooling, primarily due to overestimated surface wind speeds. In NEMO and KPP, coupling improves the timing of intraseasonal active and break phases over India, primarily the end of these phases, which are systematically too late in ATM. NEMO and KPP show a more realistic intraseasonal local phase relationship between sea surface temperature (SST) and rainfall throughout the BoB, but no configuration reproduces the observed significant lagged relationship between BoB SST and Indian rainfall. The lack of this relationship may be partly attributed to weak heat flux feedbacks to northern BoB SST, with the forecast shortwave feedback having systematically the wrong sign (positive) compared to satellite radiation, and thus contributing to SST warming at all lead times. Based on these MetUM forecasts, there is a limited impact of coupling on NWP for monsoon rainfall, both for the mean rainfall and intraseasonal variability. Further research to improve NWP for monsoon rainfall should focus on reducing MetUM atmospheric systematical biases. air–sea coupling; atmospheric convection; Bay of Bengal; Indian monsoon; intraseasonal variability; weather forecasting
Volodin, E.Volodin, E., 2021: The Mechanisms of Cloudiness Evolution Responsible for Equilibrium Climate Sensitivity in Climate Model INM-CM4-8. Geophysical Research Letters, 48(24), e2021GL096204. doi: 10.1029/2021GL096204. Current climate models demonstrate large discrepancy in equilibrium climate sensitivity (ECS). The effects of cloudiness parameterization changes on the ECS of the INM-CM4-8 climate model were investigated. This model shows the lowest ECS among CMIP6 models. Reasonable changes in the parameterization of the degree of cloudiness yielded ECS variability of 1.8–4.1 K in INM-CM4-8, which was more than half of the interval for the CMIP6 models. The three principal mechanisms responsible for the increased ECS were increased cloudiness dissipation in warmer climates due to the increased water vapor deficit in the non-cloud fraction of a cell, decreased cloudiness generation in the atmospheric boundary layer in warm climates, and the instantaneous cloud response to CO2 increases due to stratification changes. Climate sensitivity; parameterization; cloudiness; radiation forcing
Wang, Gaofeng; Wang, Tianxing; Xue, HuazhuWang, G., T. Wang, H. Xue, 2021: Validation and comparison of surface shortwave and longwave radiation products over the three poles. International Journal of Applied Earth Observation and Geoinformation, 104, 102538. doi: 10.1016/j.jag.2021.102538. Global warming has currently become a great concern to the international community, among which the three poles (the Arctic, Antarctic, and Qinghai-Tibet Plateau) are the most serious. In this paper, in order to improve the understanding of the matter and energy cycle in the three poles and even the world, eleven shortwave products, (namely, CERES-SYN, ERA5, MERRA-2, NCEP-CFSR, JRA-55, GLDAS, BESS_Rad, MCD18A1, ISCCP-HXG-SSR, GLASS and APP-x), and seven longwave products, (CERES-SYN, ERA5, MERRA-2, NCEP-CFSR, JRA-55, GLDAS, and APP-x) are evaluated and inter-compared in terms of accuracy. During the assessment, the ground measurements collected from four independent ground observation networks (BSRN, CEOP, TPDC, and NMC) are used as reference, and the being compared products are aggregated to the same spatial and temporal scales to make them comparable. To better examine their performance, the eleven radiation products are comprehensively compared in multiple spatial (original scale and 1°×1°) and temporal scales (1-hourly, 3-hourly, daily, and monthly means, and instantaneous). The results show that in the three poles, CERES-SYN and ERA5 show overall better accuracy, at daily, 1°×1° resolutions. The (r)bias and (r)RMSE are less than (3%)5 W/m2 and (23%)40 W/m2 for SWDR, and less than (3%)7 W/m2 and (15%)25 W/m2 for LWDR, respectively, over the polar regions (the Arctic and Antarctic), which are generally better than that of the Qinghai-Tibet Plateau for most products. The remote sensing products and reanalysis products have their own advantages and disadvantages at different regions. In addition, with the spatio-temporal resolution decreasing, the accuracy of radiation products will gradually increase, except for the products of MCD18A1, ISCCP-HXG-SSR, NCEP-CFSR and GLDAS. Shortwave radiation; Arctic; GLASS; ERA5; Longwave radiation; Antarctic; CERES-SYN; MCD18A1; Qinghai-Tibet Plateau; Three poles
Wang, Haibo; Zhang, Hua; Xie, Bing; Jing, Xianwen; He, Jingyi; Liu, YiWang, H., H. Zhang, B. Xie, X. Jing, J. He, Y. Liu, 2021: Evaluating the Impacts of Cloud Microphysical and Overlap Parameters on Simulated Clouds in Global Climate Models. Advances in Atmospheric Sciences. doi: 10.1007/s00376-021-0369-7. The improvement of the accuracy of simulated cloud-related variables, such as the cloud fraction, in global climate models (GCMs) is still a challenging problem in climate modeling. In this study, the influence of cloud microphysics schemes (one-moment versus two-moment schemes) and cloud overlap methods (observation-based versus a fixed vertical decorrelation length) on the simulated cloud fraction was assessed in the BCC_AGCM2.0_CUACE/Aero. Compared with the fixed decorrelation length method, the observation-based approach produced a significantly improved cloud fraction both globally and for four representative regions. The utilization of a two-moment cloud microphysics scheme, on the other hand, notably improved the simulated cloud fraction compared with the one-moment scheme; specifically, the relative bias in the global mean total cloud fraction decreased by 42.9%–84.8%. Furthermore, the total cloud fraction bias decreased by 6.6% in the boreal winter (DJF) and 1.64% in the boreal summer (JJA). Cloud radiative forcing globally and in the four regions improved by 0.3%–1.2% and 0.2%–2.0%, respectively. Thus, our results showed that the interaction between clouds and climate through microphysical and radiation processes is a key contributor to simulation uncertainty.
Wang, Jingyu; Fan, Jiwen; Feng, Zhe; Zhang, Kai; Roesler, Erika; Hillman, Benjamin; Shpund, Jacob; Lin, Wuyin; Xie, ShaochengWang, J., J. Fan, Z. Feng, K. Zhang, E. Roesler, B. Hillman, J. Shpund, W. Lin, S. Xie, 2021: Impact of a New Cloud Microphysics Parameterization on the Simulations of Mesoscale Convective Systems in E3SM. Journal of Advances in Modeling Earth Systems, 13(11), e2021MS002628. doi: 10.1029/2021MS002628. Mesoscale convective systems (MCSs) are one of the most climatically significant forms of convection because of their large role in water and energy cycles. The mesoscale features associated with MCS are difficult to represent in climate models because the relevant dynamics and physics are absent or poorly represented with coarse model resolution (∼100 km). Using a regionally refined model (RRM) with 0.25° grid spacing embedded in the Energy Exascale Earth System Model (E3SM), we explore the impact of cloud microphysics parameterizations on the simulation of precipitation, particularly MCS precipitation over the contiguous United States. The Predicted Particle Properties (P3) cloud microphysics scheme has been modified and implemented into E3SM to overcome the limitations of the default Morrison and Gettelman (MG2) scheme in which rimed precipitating ice particles (graupel/hail) are absent and frozen particles are artificially partitioned into cloud ice and snow. We show that P3 improves the simulation of precipitation statistics including frequency distribution compared with MG2 with a limited effect on the diurnal cycle. P3 predicts higher hourly rain rates, resulting in 20% more MCSs and a higher total MCS precipitation (4.4%) compared to MG2, agreeing better with observations. The improvements with P3 mainly result from improved representations of ice microphysics, which not only produces higher rain rates through melting but also leads to a stronger large-scale ascending motion by releasing more latent heating. This study suggests that improving microphysics parameterization is important for simulating MCS precipitation as future climate model resolutions continue to increase. microphysics parameterization; energy exascale Earth system model; MCS tracking; mesoscale convective system; predicted particle properties; regionally refined model
Wang, Kai; Zhang, Yang; Yahya, KhairunnisaWang, K., Y. Zhang, K. Yahya, 2021: Decadal application of WRF/Chem over the continental U.S.: Simulation design, sensitivity simulations, and climatological model evaluation. Atmospheric Environment, 118331. doi: 10.1016/j.atmosenv.2021.118331. The WRF/Chem v3.7 is applied to 2001-2010 over the continental U.S. using the National Emission Inventory (NEI). This study will provide the baseline simulation for a future work to investigate the impacts of both climate and emission changes on the future regional air quality and human health. This paper focuses on the current year simulation design, comprehensive model evaluation, and sensitivity simulations that demonstrate the impacts of different reinitialization setup, cloud physical schemes, and emission inventories on the model predictions. Nine one-month sensitivity simulations by using different reinitialization setup and cloud microphysics and cumulus parameterizations are first conducted to provide the optimal model configurations. The model performance in predicting the regional meteorology and air quality on a decadal scale is further evaluated against available surface, satellite, and reanalysis data. The decadal WRF/Chem simulation by using NEI emissions (referred to as simulation NEI) performs well for major meteorological variables such as T2, RH2, WS10, and precipitation and shows good performance for major radiation variables such as SWDOWN, OLR, and SWCF. Large model biases still exist for cloud variables due to limitations of cloud dynamics/thermodynamics treatments and uncertainties associated with satellite retrievals. The simulation NEI also predicts O3 and PM2.5 well in terms of spatiotemporal distribution. Compared to a previous study using the Representative Concentration Pathway (RCP8.5) emissions, the simulation NEI performs better for most of variables, especially for precipitation and cloud radiative forcing due to better representation of cloud processes and also for O3 and PM2.5 in terms of spatiotemporal variations due to more accurate emission inventory. The evaluation results in this work are within the range or better than other previous studies using the WRF/Chem model and lay the foundation for more realistic projection of future climate and air quality in the future work. WRF/Chem; Climatological evaluation; Continental U.S.; Decadal simulation; NEI; RCP
Wang, Mingcheng; Fu, QiangWang, M., Q. Fu, 2021: Stratosphere-Troposphere Exchange of Air Masses and Ozone Concentrations Based on Reanalyses and Observations. Journal of Geophysical Research: Atmospheres, 126(18), e2021JD035159. doi: 10.1029/2021JD035159. This study estimates the stratosphere–troposphere exchange (STE) of air masses and ozone concentrations averaged over 2007 to 2010 using the Modern Era Retrospective-Analyses for Research and Applications 2 (MERRA2) and ERA5 reanalyses, and observations. The latter includes Microwave Limb Sounder (MLS) for ozone, MLS and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) for temperatures, and A-Train measurements for diabatic heating. The extratropical downward ozone fluxes are 538 Tg year−1 from the ERA5 reanalysis, 543 Tg year−1 from the MERRA2 reanalysis, and 528–539 Tg year−1 from the observations, consistent with previous studies. Previous studies, however, did not consider tropical upward ozone flux. Here we show that the tropical upward ozone flux is 183–193 Tg year−1, which compensates about 35% of the extratropical downward ozone fluxes and should not be neglected. After considering the tropical upward ozone flux, the global ozone STE is 346 Tg year−1 from the ERA5 reanalysis, 360 Tg year−1 from the MERRA2 reanalysis, and 336–346 Tg year−1 from the observations. Those estimates (347 ± 12 Tg year−1) can be used as the contribution of ozone STE to the tropospheric ozone budget. We also investigate cloud radiative effects on the STE of air mass and ozone. At 380 K, cloud radiative effects enhance downward fluxes in the extratropics from both reanalyses and observation, but reduce and enhance upward fluxes in the tropics from reanalyses and observation, respectively. The discrepancy in the tropics is related to the tropical tropopause layer thin cirrus that is missing in the reanalyses. We find that cloud radiative effects enhance the global ozone STE by about 21%–29%. CloudSat; CALIPSO; MERRA2; cloud radiative effects; MLS; ERA5; ozone; stratosphere-troposphere exchange
Wang, Qiuyan; Zhang, Hua; Yang, Su; Chen, Qi; Zhou, Xixun; Shi, Guangyu; Cheng, Yueming; Wild, MartinWang, Q., H. Zhang, S. Yang, Q. Chen, X. Zhou, G. Shi, Y. Cheng, M. Wild, 2021: Potential Driving Factors on Surface Solar Radiation Trends over China in Recent Years. Remote Sensing, 13(4), 704. doi: 10.3390/rs13040704. The annual mean surface solar radiation (SSR) trends under all-sky, clear-sky, all-sky-no-aerosol, and clear-sky-no-aerosol conditions as well as their possible causes are analyzed during 2005–2018 across China based on different satellite-retrieved datasets to determine the major drivers of the trends. The results confirm clouds and aerosols as the major contributors to such all-sky SSR trends over China but play differing roles over sub-regions. Aerosol variations during this period result in a widespread brightening, while cloud effects show opposite trends from south to north. Moreover, aerosols contribute more to the increasing all-sky SSR trends over northern China, while clouds dominate the SSR decline over southern China. A radiative transfer model is used to explore the relative contributions of cloud cover from different cloud types to the all-types-of-cloud-cover-induced (ACC-induced) SSR trends during this period in four typical sub-regions over China. The simulations point out that the decreases in low-cloud-cover (LCC) over the North China Plain are the largest positive contributor of all cloud types to the marked annual and seasonal ACC-induced SSR increases, and the positive contributions from both high-cloud-cover (HCC) and LCC declines in summer and winter greatly contribute to the ACC-induced SSR increases over East China. The contributions from medium-low-cloud-cover (mid-LCC) and LCC variations dominate the ACC-caused SSR trends over southwestern and South China all year round, except for the larger HCC contribution in summer. radiative transfer model; cloud and aerosols; different types of cloud cover; relative contributions; SSR trends under different conditions
Wang, Tao; Wu, Dong L.; Gong, Jie; Wang, ChenxiWang, T., D. L. Wu, J. Gong, C. Wang, 2021: Long-Term Observations of Upper-Tropospheric Cloud Ice From the MLS. Journal of Geophysical Research: Atmospheres, 126(9), e2020JD034058. doi: 10.1029/2020JD034058. Upper tropospheric cloud ice varies across different timescales and plays an important role in regulating Earth's climate, but knowledge of the abundances and the variability of cloud ice has been limited for decades. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) provides an unprecedented record of cloud ice measurements since its launch in April 2006. However, CALIPSO has left the A-Train in September 2018 and entered the C-Train orbit which follows a slightly different ground track with a different local crossing time. This orbit change challenges the continuation of a long-term record of cloud ice since ice is subject to stronger diurnal cycle. Fortunately, the Aura Microwave Limb Sounder (MLS), still as a member of the A-Train, has a consistent local crossing time and has measured high quality radiance since launch in 2004, and will probably continue beyond 2024. We present the use of MLS 640-GHz cloud-induced radiance (Tcir) to build a robust upper tropospheric partial ice water path (pIWP) product due to its high dynamical range to different sizes of ice particles. The MLS rebuilt pIWP, which extends nearly two decades, captures the spatial and temporal variabilities of upper tropospheric cloud ice that CALIOP is capable of measuring. This provides valuable alternative for studying the upper tropospheric cloud ice and possibly provides a more consistent input to climate studies. cloud; ice water path; ice water content; caliop; enso; mls
Wang, Tianyuan; Zhou, Lihang; Tan, Changyi; Divakarla, Murty; Pryor, Ken; Warner, Juying; Wei, Zigang; Goldberg, Mitch; Nalli, Nicholas R.Wang, T., L. Zhou, C. Tan, M. Divakarla, K. Pryor, J. Warner, Z. Wei, M. Goldberg, N. R. Nalli, 2021: Validation of Near-Real-Time NOAA-20 CrIS Outgoing Longwave Radiation with Multi-Satellite Datasets on Broad Timescales. Remote Sensing, 13(19), 3912. doi: 10.3390/rs13193912. The Outgoing Longwave Radiation (OLR) package was first developed as a stand-alone application, and then integrated into the National Oceanic and Atmospheric Administration (NOAA) Unique Combined Atmospheric Processing System (NUCAPS) hyperspectral sounding retrieval system. An objective of this package is to provide near-real-time OLR products derived from the Cross Track Infrared Sounder (CrIS) onboard the Joint Polar Satellite System (JPSS) satellites. It was initially developed and validated with CrIS onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite, and has been expanded to JPSS-1 (renamed NOAA-20 after launch) datasets that are currently available to the public. In this paper, we provide the results of detailed validation tests with NOAA-20 CrIS for large and wide representative conditions at a global scale. In our validation tests, the observations from Clouds and Earth’s Radiant Energy System (CERES) on Aqua were treated as the absolute reference or “truth”, and those from SNPP CrIS OLR were used as the transfer standard. The tests were performed on a 1°×1° global spatial grid over daily, monthly, and yearly timescales. We find that the CrIS OLR products from NOAA-20 agree exceptionally well with those from Aqua CERES and SNPP CrIS OLR products in all conditions: the daily bias is within ±0.6 Wm−2, and the standard deviation (STD) ranges from 4.88 to 9.1 Wm−2. The bias and the STD of OLR monthly mean are better, within 0.3 and 2.0 Wm−2, respectively. These findings demonstrate the consistency between NOAA-20 and SNPP CrIS OLR up to annual scales, and the robustness of NUCAPS CrIS OLR products. radiation budget; validation; outgoing longwave radiation; OLR; NOAA-20; CrIS; NUCAPS
Wang, Tongxin; Zhang, Hongyan; Zhao, Jianjun; Guo, Xiaoyi; Xiong, Tao; Wu, RihanWang, T., H. Zhang, J. Zhao, X. Guo, T. Xiong, R. Wu, 2021: Shifting Contribution of Climatic Constraints on Evapotranspiration in the Boreal Forest. Earth's Future, 9(8), e2021EF002104. doi: 10.1029/2021EF002104. The global evapotranspiration (ET) shows an increasing trend with global warming in recent decades, while ET variation in different regions is still uncertain. Boreal forest ecosystem, as one of the most sensitive regions to climate change, are still poorly understood due to the sparse observation and the changing of ET in the boreal forest has been covered up for lower values compared to lower-latitude regions. Based on the PT-JPL model, we estimated the ET in the boreal forest during 1982–2015. The annual ET showed an increasing trend (0.5073 mm year−1). Seventy percentage of the boreal forest area is increasing which mainly occurred in Central Canada, Alaska, Central Siberia and Northern Europe, while 24% is decreasing, which occurred in the southern Siberia, Northern Mongolia and Northern Canada. The quantification of basic climatic factors shows that atmospheric demand is the main factor with an increasing trend which is accordance with the (a) increasing temperature; (b) annual precipitation is increasing providing increasing water supply for boreal forest. Factorial experiments were also conducted and showed that the climatic constraints that contribute mainly to ET have gradually shifted from net radiation to moisture restriction in the boreal forest. The moisture control tendency indicated that ET in the boreal forest was gradually controlled by humidity rather than energy, suggesting a limited water supply and an intensifying water cycle in the boreal forest. climate change; PT-JPL model; evapotranspiration; boreal forest
Wang, Wei; Chakraborty, T. C.; Xiao, Wei; Lee, XuhuiWang, W., T. C. Chakraborty, W. Xiao, X. Lee, 2021: Ocean surface energy balance allows a constraint on the sensitivity of precipitation to global warming. Nature Communications, 12(1), 2115. doi: 10.1038/s41467-021-22406-7. Climate models generally predict higher precipitation in a future warmer climate. Whether the precipitation intensification occurred in response to historical warming continues to be a subject of debate. Here, using observations of the ocean surface energy balance as a hydrological constraint, we find that historical warming intensified precipitation at a rate of 0.68 ± 0.51% K−1, which is slightly higher than the multi-model mean calculation for the historical climate (0.38 ± 1.18% K−1). The reduction in ocean surface albedo associated with melting of sea ice is a positive contributor to the precipitation temperature sensitivity. On the other hand, the observed increase in ocean heat storage weakens the historical precipitation. In this surface energy balance framework, the incident shortwave radiation at the ocean surface and the ocean heat storage exert a dominant control on the precipitation temperature sensitivity, explaining 91% of the inter-model spread and the spread across climate scenarios in the Intergovernmental Panel on Climate Change Fifth Assessment Report.
Wang, Xuejia; Chen, Deliang; Pang, Guojin; Anwar, Samy A.; Ou, Tinghai; Yang, MeixueWang, X., D. Chen, G. Pang, S. A. Anwar, T. Ou, M. Yang, 2021: Effects of cumulus parameterization and land-surface hydrology schemes on Tibetan Plateau climate simulation during the wet season: insights from the RegCM4 model. Climate Dynamics. doi: 10.1007/s00382-021-05781-1. Dynamical downscaling generally performs poorly on the Tibetan Plateau (TP), due to the region’s complex topography and several aspects of model physics, especially convection and land surface processes. This study investigated the effects of the cumulus parameterization scheme (CPS) and land-surface hydrology scheme (LSHS) on TP climate simulation during the wet season using the RegCM4 regional climate model. To address these issues and seek an optimal simulation, we conducted four experiments at a 20 km resolution using various combinations of two CPSs (Grell and MIT-Emanuel), two LSHSs (the default TOPMODEL [TOP], and Variable Infiltration Capacity [VIC]). The simulations in terms of 2-m air temperature, precipitation (including large-scale precipitation [LSP] and convective precipitation [CP]), surface energy-water balance, as well as atmospheric moisture flux transport and vertical motion were compared with surface and satellite-based observations as well as the ERA5 reanalysis dataset for the period 2006–2016. The results revealed that the model using the Grell and TOP schemes better reproduced air temperature but with a warm bias, part of which could be significantly decreased by the MIT scheme. All schemes simulated a reasonable spatial distribution of precipitation, with the best performance in the experiment using the MIT and VIC schemes. Excessive precipitation was produced by the Grell scheme, mainly due to overestimated LSP, while the MIT scheme largely reduced the overestimation, and the simulated contribution of CP to total precipitation was in close agreement with the ERA5 data. The RegCM4 model satisfactorily captured diurnal cycles of precipitation amount and frequency, although there remained some differences in phase and magnitude, which were mainly caused by the CPSs. Relative to the Grell scheme, the MIT scheme yielded a weaker surface heating by reducing net radiation fluxes and the Bowen ratio. Consequently, anomalous moisture flux transport was substantially reduced over the southeastern TP, leading to a decrease in precipitation. The VIC scheme could also help decrease the wet bias by reducing surface heating. Further analysis indicated that the high CP in the MIT simulations could be attributed to destabilization in the low and mid-troposphere, while the VIC scheme tended to inhibit shallow convection, thereby decreasing CP. This study’s results also suggest that CPS interacts with LSHS to affect the simulated climate over the TP.
Wang, Yi-Chi; Hsu, Huang-Hsiung; Chen, Chao-An; Tseng, Wan-Ling; Hsu, Pei-Chun; Lin, Cheng-Wei; Chen, Yu-Luen; Jiang, Li-Chiang; Lee, Yu-Chi; Liang, Hsin-Chien; Chang, Wen-Ming; Lee, Wei-Liang; Shiu, Chein-JungWang, Y., H. Hsu, C. Chen, W. Tseng, P. Hsu, C. Lin, Y. Chen, L. Jiang, Y. Lee, H. Liang, W. Chang, W. Lee, C. Shiu, 2021: Performance of the Taiwan Earth System Model in Simulating Climate Variability Compared With Observations and CMIP6 Model Simulations. Journal of Advances in Modeling Earth Systems, 13(7), e2020MS002353. doi: 10.1029/2020MS002353. This study evaluates the performance of the Taiwan Earth System Model version 1 (TaiESM1) in simulating the observed climate variability in the historical simulation of the Coupled Model Intercomparison Phase 6 (CMIP6). TaiESM1 is developed on the basis of the Community Earth System Model version 1.2.2, with the inclusion of several new physical schemes and improvements in the atmosphere model. The new additions include an improved triggering function in the cumulus convection scheme, a revised distribution-based formula in the cloud fraction scheme, a new aerosol scheme, and a unique scheme for three-dimensional surface absorption of shortwave radiation that accounts for the influence of complex terrains. In contrast to the majority of model evaluation processes, which focus mainly on the climatological mean, this evaluation focuses on climate variability parameters, including the diurnal rainfall cycle, precipitation extremes, synoptic eddy activity, intraseasonal fluctuation, monsoon evolution, and interannual and multidecadal atmospheric and oceanic teleconnection patterns. A series of intercomparisons between the simulations of TaiESM1 and CMIP6 models and observations indicate that TaiESM1, a participating model in CMIP6, can realistically simulate the observed climate variability at various time scales and are among the leading CMIP6 models in terms of many key climate features. model evaluation; CMIP6; climate variability; TaiESM
Wang, Yipu; Li, Rui; Hu, Jiheng; Wang, Xuewen; Kabeja, Crispin; Min, Qilong; Wang, YuWang, Y., R. Li, J. Hu, X. Wang, C. Kabeja, Q. Min, Y. Wang, 2021: Evaluations of MODIS and microwave based satellite evapotranspiration products under varied cloud conditions over East Asia forests. Remote Sensing of Environment, 264, 112606. doi: 10.1016/j.rse.2021.112606. Satellite remote sensing is an important tool to retrieve terrestrial evapotranspiration (ET). Widely-used MOD16 ET product (MOD-ET) is a representative of Penman-Monteith method coupled with MODerate Resolution Imaging Spectroradiometer (MODIS) optic observations. Although MOD-ET has been extensively evaluated over the world, its accuracy under various cloud conditions remains unevaluated. Combining MODIS-observed cloud cover (Frc) and in-situ measurements at sixteen forests sites in East Asia, we evaluated 8-day MOD-ET and its primary MODIS inputs (i.e. LAI, FPAR and albedo) from clear to cloudy sky. A new satellite microwave ET method based on microwave Emissivity Difference Vegetation Index (EDVI-ET) was also compared with MOD-ET. Results showed that the accuracy of MOD-ET was highly variable under the changing Frc over the forests. The largest bias (>30%) in MOD-ET was found under Frc 30%) deteriorated the bias in MOD-ET (20%–30%). In contrast, EDVI-ET performed stably with lower bias (0.81) under other sky conditions. Further investigation found that MOD-ET over four tropical coastal forests contributed most to the bias, especially under least cloudy sky. A case study at a tropical forest showed that MODIS LAI/FPAR and surface albedo products were overestimated, which could directly cause the overestimation of canopy-scale conductance and the underestimation of net solar radiation in MOD-ET method, respectively. Analysis showed that the bias in MOD-ET was significantly related to the bias in MODIS LAI under various Frc, but it was weakly related to that in MODIS albedo, suggesting that LAI-based conductance might dominate the overestimation of MOD-ET. During a consecutive cloud cover period when fewer reliable MODIS pixels are available, slight increase of clouds partly reduced MODIS-observed signals of LAI/FPAR and increased those of albedo over the tropical forest, resulting in the lower bias in MOD-ET. More clouds reduced surface MODIS albedo and might increase the uncertainty in all-sky shortwave radiation from reanalysis data, which deteriorated MOD-ET accuracy under overcast sky. Our study highlighted the importance of cloud impacts on the satellite ET estimation. Emissivity difference vegetation index (EDVI); Cloudy effects; Evapotranspiration (ET); Forest; MODIS ET
Wang, Yonglin; Zhou, Lei; Zhuang, Jie; Sun, Leigang; Chi, YonggangWang, Y., L. Zhou, J. Zhuang, L. Sun, Y. Chi, 2021: The spatial heterogeneity of the relationship between gross primary production and sun-induced chlorophyll fluorescence regulated by climate conditions during 2007–2018. Global Ecology and Conservation, 29, e01721. doi: 10.1016/j.gecco.2021.e01721. The strong relationship between gross primary productivity (GPP) and sun-induced chlorophyll fluorescence (SIF) provided a novel perspective to estimate the terrestrial GPP based on satellite SIF. However, the influence of environmental conditions on the relationship between GPP and SIF is still unclear. In this study, we synthesized GOME-2 SIF and FLUXCOM GPP coupled with climate data to explore the spatial pattern of the GPP-SIF relationship and its sensitivity to climate conditions at global scale during 2007–2018. The slope (GPP/SIF) of the intercept-free linear regression, which contained information about the allocation of light energy for fluorescence and photosynthesis, was used to represent the GPP-SIF relationship. Our study found that the slope and R2 of the GPP-SIF relationship were spatially heterogeneous, with high slope mainly distributed in the tropical regions and boreal regions and the high R2 mainly concentrated in temperate ecosystems of the Northern Hemisphere. In climate regimes, we found that the GPP-SIF relationship was jointly constrained by environmental variables and the slope had a significant decreasing trend in climate regions from high mean annual temperature (MAT) and low mean annual photosynthetically active radiation (MAR) to low MAT and high MAR. Furthermore, the slope and mean annual precipitation (MAP) have a positive correlation, which indicated the GPP-SIF relationship was climate-dependent. Environmental stress may destroy the relationship between fluorescence and photosynthesis by increasing non-photochemical quenching (NPQ). Our research showed that environmental conditions regulated the light energy distribution for fluorescence and photosynthesis, so accurate estimation of terrestrial ecosystem productivity based on SIF should consider the constraints of climate variables. Climate-dependent; GPP/SIF; Seasonality; Spatial pattern; The GPP-SIF relationship
Wei, Jian; Ren, Tong; Yang, Ping; DiMarco, Steven F.; Mlawer, EliWei, J., T. Ren, P. Yang, S. F. DiMarco, E. Mlawer, 2021: An Improved Ocean Surface Albedo Computational Scheme: Structure and Performance. Journal of Geophysical Research: Oceans, 126(8), e2020JC016958. doi: 10.1029/2020JC016958. Ocean surface albedo (OSA) is an important factor for the transfer of radiation in the coupled atmosphere-ocean system. By resolving the spectral variations of the reflective properties for incident direct and diffuse solar radiation, we develop an OSA computational scheme to study the impact of ocean biogeochemistry on the air-sea boundary condition of solar radiative transfer in the atmosphere. The new scheme is implemented for the General Circulation Model applications of the shortwave rapid radiative transfer model RRTMG_SW, a radiative transfer model used extensively in regional and global models. We show that a number of OSA schemes lead to underestimated results in comparison with in-situ measurements obtained at a site 25 km east of Virginia Beach. The scheme developed in this study considers multiple influential factors and is robust in terms of the mean absolute percentage error (MAPE) and the root mean square error in comparison with in-situ measurements. Furthermore, the new simulations are highly consistent with the Clouds and the Earth's Radiant Energy System (CERES) OSA distribution on a global scale. However, the theoretical results show slight differences compared with the CERES OSA under all sky conditions and overestimate the OSA in the subpolar Southern Ocean under clear sky conditions. The assumption of a uniform phase function, which neglects the spatial variability of the optical properties of oceanic particles, is largely responsible for the primary source of uncertainties in an OSA scheme. climate model; ocean surface albedo; shortwave radiative transfer
Wei, Jianfen; Wang, Zhaomin; Gu, Mingyi; Luo, Jing-Jia; Wang, YunheWei, J., Z. Wang, M. Gu, J. Luo, Y. Wang, 2021: An evaluation of the Arctic clouds and surface radiative fluxes in CMIP6 models. Acta Oceanologica Sinica, 40(1), 85-102. doi: 10.1007/s13131-021-1705-6. To assess the performances of state-of-the-art global climate models on simulating the Arctic clouds and surface radiation balance, the 2001–2014 Arctic Basin surface radiation budget, clouds, and the cloud radiative effects (CREs) in 22 coupled model intercomparison project 6 (CMIP6) models are evaluated against satellite observations. For the results from CMIP6 multi-model mean, cloud fraction (CF) peaks in autumn and is lowest in winter and spring, consistent with that from three satellite observation products (CloudSat-CALIPSO, CERES-MODIS, and APP-x). Simulated CF also shows consistent spatial patterns with those in observations. However, almost all models overestimate the CF amount throughout the year when compared to CERES-MODIS and APP-x. On average, clouds warm the surface of the Arctic Basin mainly via the longwave (LW) radiation cloud warming effect in winter. Simulated surface energy loss of LW is less than that in CERES-EBAF observation, while the net surface shortwave (SW) flux is underestimated. The biases may result from the stronger cloud LW warming effect and SW cooling effect from the overestimated CF by the models. These two biases compensate each other, yielding similar net surface radiation flux between model output (3.0 W/m2) and CERES-EBAF observation (6.1 W/m2). During 2001–2014, significant increasing trend of spring CF is found in the multi-model mean, consistent with previous studies based on surface and satellite observations. Although most of the 22 CMIP6 models show common seasonal cycles of CF and liquid water path/ice water path (LWP/IWP), large inter-model spreads exist in the amounts of CF and LWP/IWP throughout the year, indicating the influences of different cloud parameterization schemes used in different models. Cloud Feedback Model Intercomparison Project (CFMIP) observation simulator package (COSP) is a great tool to accurately assess the performance of climate models on simulating clouds. More intuitive and credible evaluation results can be obtained based on the COSP model output. In the future, with the release of more COSP output of CMIP6 models, it is expected that those inter-model spreads and the model-observation biases can be substantially reduced. Longer term active satellite observations are also necessary to evaluate models’ cloud simulations and to further explore the role of clouds in the rapid Arctic climate changes.
Wei, Yu; Zhang, Xiaotong; Li, Wenhong; Hou, Ning; Zhang, Weiyu; Xu, Jiawen; Feng, Chunjie; Jia, Kun; Yao, Yunjun; Cheng, Jie; Jiang, Bo; Wang, Kaicun; Liang, ShunlinWei, Y., X. Zhang, W. Li, N. Hou, W. Zhang, J. Xu, C. Feng, K. Jia, Y. Yao, J. Cheng, B. Jiang, K. Wang, S. Liang, 2021: Trends and Variability of Atmospheric Downward Longwave Radiation Over China From 1958 to 2015. Earth and Space Science, 8(2), e2020EA001370. doi: https://doi.org/10.1029/2020EA001370. Surface downward longwave radiation (SDLR) is a major component of the energy budget. Although studies have reported the spatiotemporal variations of SDLR in China, the spatiotemporal coverage of the situ measurements used is always limited. In this study, the gradient boosting regression tree (GBRT) was developed to reconstruct SDLR based on air temperature (Ta), relative humidity (RH), and downward shortwave radiation (DSR). Ground measurements collected at the Baseline Surface Radiation Network (BSRN) and the Arid and Semi-arid Region Collaborative Observation Project (ASRCOP) were used to build and evaluate the GBRT model. The evaluation results showed that the daily SDLR estimates are correlated well with the SDLR in situ, with an overall root mean square errors (RMSE) of 16.5 Wm−2 and a correlation coefficient (R) value of 0.91 for the validation data set. Comparison with existing SDLR products showed that accuracy and trends of the SDLR estimates based on the GBRT method are reasonable. To obtain long-term SDLR data for spatiotemporal analysis over China, densely distributed reconstructed DSR and ground measured Ta and RH collected at 756 Chinese Meteorological Administration (CMA) stations were used as input to estimate the SDLR based on the GBRT method over China during 1958–2015. The long-term estimated SDLRs at the selected 563 stations showed that SDLR increased at an average rate of 1.3 Wm−2 per decade over China from 1958 to 2015. The trend of SDLR is positively correlated with the trend in Ta and water vapor pressure, whereas negatively correlated with the trend in DSR. downward longwave radiation; GBRT; CMA; MK trend test
Wu, Yuxuan; Xi, Yi; Feng, Maoyuan; Peng, ShushiWu, Y., Y. Xi, M. Feng, S. Peng, 2021: Wetlands Cool Land Surface Temperature in Tropical Regions but Warm in Boreal Regions. Remote Sensing, 13(8), 1439. doi: 10.3390/rs13081439. Wetlands play a critical role in global hydrological and biogeochemical cycles. Regulating the regional climate is one of the most important ecosystem services of natural wetlands. However, the impact of wetlands on local temperature on the global scale and the attribution is still unclear. This study utilizes the satellite-based products (land surface temperature (LST), albedo, and evapotranspiration (ET)) to evaluate the difference in LST between wetlands and their adjacent landcover types and the possible drivers. Here we show that on average for the whole year, wetlands have a cooling effect in tropical regions, but have a warming effect in boreal regions. The impacts of wetlands on LST show great seasonality in the boreal regions; i.e., the wetlands have a warming effect in winter but a cooling effect in summer. The difference in albedo and ET between wetlands and the other landcover types only interprets 30% of temporal variation of the difference in LST. Due to the large water storage in wetlands, the ground heat flux (G) may interpret the rest of the impact, absorbing energy in summer and releasing energy in winter in wetlands, which has often been neglected in previous studies. Our results indicate that it is critical to comprehensively consider the effects of wetland restoration in different regions to realize potential climatic benefits in the future. albedo; remote sensing; land surface temperature; evapotranspiration; surface energy balance; wetlands
Xia, Yan; Hu, Yongyun; Huang, Yi; Zhao, Chuanfeng; Xie, Fei; Yang, YikunXia, Y., Y. Hu, Y. Huang, C. Zhao, F. Xie, Y. Yang, 2021: Significant Contribution of Severe Ozone Loss to the Siberian-Arctic Surface Warming in Spring 2020. Geophysical Research Letters, 48(8), e2021GL092509. doi: https://doi.org/10.1029/2021GL092509. Severe ozone loss and significant surface warming anomalies in the Siberian Arctic were observed in spring 2020. Here, we show that the anomalous surface warming was likely related to the ozone loss. The dramatic Arctic ozone loss in March was shifted to Siberia in April and May, which largely cools the lower stratosphere and leads to an increase of high clouds by modifying the static stability in the upper troposphere. This further results in an increase of longwave radiation at surface which likely contributes to surface warming. Multiple linear regression demonstrates that ozone loss contributes most of the surface warming in April, while the Arctic Oscillation and ice-albedo feedback play a minor role. In May, both ozone loss and ice-albedo feedback contribute to the surface warming. These results support that surface warming in the Siberian Arctic could occur in April and May when severe ozone loss occurs in March. cloud radiative effect; ice-albedo feedback; stratospheric ozone; Arctic warming; the Siberian Arctic
Xu, Hui; Guo, Jianping; Li, Jian; Liu, Lin; Chen, Tianmeng; Guo, Xiaoran; Lyu, Yanmin; Wang, Ding; Han, Yi; Chen, Qi; Zhang, YongXu, H., J. Guo, J. Li, L. Liu, T. Chen, X. Guo, Y. Lyu, D. Wang, Y. Han, Q. Chen, Y. Zhang, 2021: The Significant Role of Radiosonde-measured Cloud-base Height in the Estimation of Cloud Radiative Forcing. Advances in Atmospheric Sciences. doi: 10.1007/s00376-021-0431-5. The satellite-based quantification of cloud radiative forcing remains poorly understood, due largely to the limitation or uncertainties in characterizing cloud-base height (CBH). Here, we use the CBH data from radiosonde measurements over China in combination with the collocated cloud-top height (CTH) and cloud properties from MODIS/Aqua to quantify the impact of CBH on shortwave cloud radiative forcing (SWCRF). The climatological mean SWCRF at the surface (SWCRFSUR), at the top of the atmosphere (SWCRFTOA), and in the atmosphere (SWCRFATM) are estimated to be −97.14, −84.35, and 12.79 W m−2, respectively for the summers spanning 2010 to 2018 over China. To illustrate the role of the cloud base, we assume four scenarios according to vertical profile patterns of cloud optical depth (COD). Using the CTH and cloud properties from MODIS alone results in large uncertainties for the estimation of SWCRFATM, compared with those under scenarios that consider the CBH. Furthermore, the biases of the CERES estimation of SWCRFATM tend to increase in the presence of thick clouds with low CBH. Additionally, the discrepancy of SWCRFATM relative to that calculated without consideration of CBH varies according to the vertical profile of COD. When a uniform COD vertical profile is assumed, the largest SWCRF discrepancies occur during the early morning or late afternoon. By comparison, the two-point COD vertical distribution assumption has the largest uncertainties occurring at noon when the solar irradiation peaks. These findings justify the urgent need to consider the cloud vertical structures when calculating the SWCRF which is otherwise neglected.
Xu, Jianglei; Jiang, Bo; Liang, Shunlin; Li, Xiuxia; Wang, Yezhe; Peng, Jianghai; Chen, Hongkai; Liang, Hui; Li, ShaopengXu, J., B. Jiang, S. Liang, X. Li, Y. Wang, J. Peng, H. Chen, H. Liang, S. Li, 2021: Generating a High-Resolution Time-Series Ocean Surface Net Radiation Product by Downscaling J-OFURO3. IEEE Transactions on Geoscience and Remote Sensing, (In Press). doi: 10.1109/TGRS.2020.3021585. The ocean surface net radiation (Rn) characterizing ocean surface radiation budget is a key variable in ocean climate modeling and analysis. In this study, a downscaling scheme was developed to generate a high-resolution (0.05°) time-series (2002-2013) daily ocean surface Rn from the third-generation Japanese Ocean Flux Data Sets with Use of Remote-Sensing Observations (J-OFURO3) at 0.25° based on the Advanced Very-High-Resolution Radiometer (AVHRR) top-of-atmosphere (TOA) observations (AVH021C) and other ancillary information (Clearness Index and cloud mask). This downscaling scheme includes the statistical downscaling models and the residual correction post-processing. A series of angle-dependent downscaling statistical models were established between the daily ocean surface Rn in J-OFURO3 and the AVHRR TOA data, and then, the residual correction was conducted to the model estimates Rn_AVHRR_est to obtain the final downscaled data set Rn_AVHRR. Validation against the measurements from 57 moored buoy sites in six ocean observing networks shows the high accuracy of the downscaled estimates Rn_AVHRR_est with a R² of 0.88, RMSE of 23.44 W·m⁻², and bias of -0.14 W·m⁻² under all-sky condition. The results of the spatio-temporal analysis in Rn_AVHRR and intercomparison with Cloud and the Earth's Radiant Energy System (CERES) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) products also indicated that the superior of the Rn_AVHRR with more detailed information especially in the hot spot regions, such as central tropical Pacific (warming pool), Atlantic and Equatorial Eastern Indian Ocean (EIO). Land surface; Remote sensing; Meteorology; Sea surface; net radiation; Advanced Very-High-Resolution Radiometer (AVHRR); downscaling; ocean surface; Ocean temperature; remote sensing.; Spatial resolution
Xu, Jianglei; Liang, Shunlin; Jiang, BoXu, J., S. Liang, B. Jiang, 2021: A global long term (1981–2019) daily land surface radiation budget product from AVHRR satellite data using a residual convolutional neural network. Earth System Science Data Discussions, 1-36. doi: 10.5194/essd-2021-250. Abstract. The surface radiation budget, also known as all-wave net radiation (Rn), is a key parameter for various land surface processes including hydrological, ecological, agricultural, and biogeochemical processes. Satellite data can be effectively used to estimate Rn, but existing satellite products have coarse spatial resolutions and limited temporal coverage. In this study, a point-surface matching estimation (PSME) method is proposed to estimate surface Rn using a residual convolutional neural network (RCNN) integrating spatially adjacent information to improve the accuracy of retrievals. A global high-resolution (0.05°) long-term (1981–2019) Rn product was subsequently generated from Advanced Very High-Resolution Radiometer (AVHRR) data. Specifically, the RCNN was employed to establish a nonlinear relationship between globally distributed ground measurements from 537 sites and AVHRR top of atmosphere (TOA) observations. Extended triplet collocation (ETC) technology was applied to address the spatial scale mismatch issue resulting from the low spatial support of ground measurements within the AVHRR footprint by selecting reliable sites for model training. The overall independent validation results show that the generated AVHRR Rn product is highly accurate, with R2, root-mean-square error (RMSE), and bias of 0.84, 26.66 Wm−2 (31.66 %), and 1.59 Wm−2 (1.89 %), respectively. Inter-comparisons with three other Rn products, i.e., the 5 km Global Land Surface Satellite (GLASS), the 1° Clouds and the Earth's Radiant Energy System (CERES), and the 0.5° × 0.625° Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2), illustrate that our AVHRR Rn retrievals have the best accuracy under all of the considered surface and atmospheric conditions, especially thick cloud or hazy conditions. The spatiotemporal analyses of these four Rn datasets indicate that the AVHRR Rn product reasonably replicates the spatial pattern and temporal evolution trends of Rn observations. This dataset is freely available at https://doi.org/10.5281/zenodo.5509854 for 1981–2019 (Xu et al., 2021).
Xu, Jiawen; Zhang, Xiaotong; Feng, Chunjie; Yang, Shuyue; Guan, Shikang; Jia, Kun; Yao, Yunjun; Xie, Xianhong; Jiang, Bo; Cheng, Jie; Zhao, XiangXu, J., X. Zhang, C. Feng, S. Yang, S. Guan, K. Jia, Y. Yao, X. Xie, B. Jiang, J. Cheng, X. Zhao, 2021: Evaluation of Surface Upward Longwave Radiation in the CMIP6 Models with Ground and Satellite Observations. Remote Sensing, 13(21), 4464. doi: 10.3390/rs13214464. Surface upward longwave radiation (SULR) is an indicator of thermal conditions over the Earth’s surface. In this study, we validated the simulated SULR from 51 Coupled Model Intercomparison Project (CMIP6) general circulation models (GCMs) through a comparison with ground measurements and satellite-retrieved SULR from the Clouds and the Earth’s Radiant Energy System, Energy Balanced and Filled (CERES EBAF). Moreover, we improved the SULR estimations by a fusion of multiple CMIP6 GCMs using multimodel ensemble (MME) methods. Large variations were found in the monthly mean SULR among the 51 CMIP6 GCMs; the bias and root mean squared error (RMSE) of the individual CMIP6 GCMs at 133 sites ranged from −3 to 24 W m−2 and 22 to 38 W m−2, respectively, which were higher than those found between the CERES EBAF and GCMs. The CMIP6 GCMs did not improve the overestimation of SULR compared to the CMIP5 GCMs. The Bayesian model averaging (BMA) method showed better performance in simulating SULR than the individual GCMs and simple model averaging (SMA) method, with a bias of 0 W m−2 and an RMSE of 19.29 W m−2 for the 133 sites. In terms of the global annual mean SULR, our best estimation for the CMIP6 GCMs using the BMA method was 392 W m−2 during 2000–2014. We found that the SULR varied between 386 and 393 W m−2 from 1850 to 2014, exhibiting an increasing tendency of 0.2 W m−2 per decade (p < 0.05). CMIP5; GCMs; CMIP6; Bayesian model averaging; multimodel ensemble; surface upward longwave radiation (SULR)
Xu, Lingxuan; Sun, Shanlei; Chen, Haishan; Chai, Rongfan; Wang, Jiazhi; Zhou, Yang; Ma, Qianrong; Chotamonsak, Chakrit; Wangpakapattanawong, PrasitXu, L., S. Sun, H. Chen, R. Chai, J. Wang, Y. Zhou, Q. Ma, C. Chotamonsak, P. Wangpakapattanawong, 2021: Changes in the reference evapotranspiration and contributions of climate factors over the Indo–China Peninsula during 1961–2017. International Journal of Climatology, 41(15), 6511-6529. doi: 10.1002/joc.7209. Given the key roles of the Indo–China Peninsula (ICP) in weather and climate systems, hydrometeorology, and ecology, the annual and monthly changes in the Food and Agriculture Organization-56 Penman–Monteith reference evapotranspiration (ET0), which was calculated based on the Climatic Research Unit datasets, were investigated in ICP during 1961–2017. The annual ICP ET0 significantly (p < .05) increased, with different increasing tendencies in most months. In particular, larger and more significant (p < .05) ET0 values were found during October–December. The annual and monthly ET0 changes showed evident spatial differences, characterized by increases in more than 50% of the ICP area except for decreases in around 70% of that area during March–May. A sensitivity experiment-based separation method was utilized to evaluate the contribution of each influential factor, and the corresponding determinants were identified by comparing the contributions. Results showed that the annual ICP ET0 increase was attributed to the increased vapour pressure deficit (Vpd). However, the annual determinants varied spatially, with net solar radiation (Rn) in the southern region of ICP, wind speed (Wnd) in the northeast, and Vpd in the remaining regions. The monthly ICP determinant was Wnd in January, March–May and December, and Vpd for the remaining months. Despite different spatial patterns of monthly dominants, Vpd and Wnd were the determinants with the most extensive distributions over ICP (>75% of ICP in total). The results of this study can significantly fulfil the research gap regarding the ICP ET0 changes and the underlying mechanisms. Meanwhile, this study provides fundamental and necessary information for protecting biodiversity and understanding hydrometeorological extreme events, thus promoting specific measures to sustain the ICP development. reference evapotranspiration; Indo–China Peninsula; quantitative analysis; separation method; trends
Yamazaki, Kuniko; Sexton, David M. H.; Rostron, John W.; McSweeney, Carol F.; Murphy, James M.; Harris, Glen R.Yamazaki, K., D. M. H. Sexton, J. W. Rostron, C. F. McSweeney, J. M. Murphy, G. R. Harris, 2021: A perturbed parameter ensemble of HadGEM3-GC3.05 coupled model projections: part 2: global performance and future changes. Climate Dynamics, 56(11), 3437-3471. doi: 10.1007/s00382-020-05608-5. This paper provides a quantitative assessment of large-scale features in a perturbed parameter ensemble (PPE) of Met Office Unified Model HadGEM-GC3.05 in coupled global historical and future simulations. The main motivation for the simulations is to provide a major component of the UK Climate Projections 2018 (UKCP18), but they will also be used to make worldwide projections and inform future model development. Initially, a 25-member PPE, with 25 different parameter combinations, was simulated. Five members were subsequently dropped because either their simulated climate was unrealistically cool by 1970 or they suffered from numerical instabilities. The remaining 20 members were evaluated after completing the historical phase (1900–2005) against 13 separately selected Climate Model Intercomparison Project Phase 5 (CMIP5) models, and five more members were dropped. The final product is a combined projection system of 15 PPE members and 13 CMIP5 models, which has a number of benefits. In particular, the range of outcomes available from the combined set of 28 is often larger than from either of the two constituent ensembles, thus providing users with a more complete picture of plausible impacts. Here we mainly describe the evaluation process of the 20 PPE members. We evaluate biases in a number of important properties of the global coupled system, including assessment of climatological averages, coupled modes of internal variability and historical and future changes. The parameter combinations yielded plausible yet diverse atmosphere and ocean model behaviours. The range of global temperature changes is narrow, largely driven by use of different CO2 pathways. The range of global warming is seemingly not linked to range of feedbacks estimated from atmosphere-only runs, though we caution that the range of the latter is narrow relative to CMIP5, and therefore this result is not unexpected. This is the second of two papers describing the generation of the PPE for UKCP18 projections. Part 1 (Sexton et al. 2021) describes the selection of 25 parameter combinations of 47 atmosphere and land surface parameters, using a set of cheap atmosphere-only runs at a coarser resolution from nearly 3000 samples of parameter space.
Yang, Feng; Cheng, Jie; Zeng, QiYang, F., J. Cheng, Q. Zeng, 2021: Validation of a Cloud-Base Temperature-Based Single-Layer Cloud Model for Estimating Surface Longwave Downward Radiation. IEEE Geoscience and Remote Sensing Letters, 1-5. doi: 10.1109/LGRS.2021.3083502. As one of the four components of surface radiation balance, surface longwave downward radiation (SLDR) greatly affects the accurate characterization of hydrological, ecological, and biochemical processes. Since cloud-base temperature (CBT)-based single-layer cloud models (SLCMs) have advantages in both their strong physical mechanisms and abilities to produce high spatial resolution SLDR products, this study validated a CBT-based SLCM developed at the global scale using in situ observations collected by the baseline surface radiation network (BSRN) in conjunction with Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) cloud products and Modern-Era Retrospective Analysis For Research And Applications, Version 2 (MERRA-2) reanalysis data. Overall, the CBT-based SLCM achieved a relatively high SLDR estimation accuracy for the Terra and Aqua satellites, with biases better than -1.2 W/m² and root-mean-squared error (RMSE) values better than 29.9 W/m². However, its random RMSE was slightly worse than those of two Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint (SSF) SLDR products due to the larger spatial variability that exists at the Earth's surface when it is quantified at a high spatial resolution (1 km). Additionally, the CBT-based SLCM outperformed two existing cloud-top temperature (CTT)-based SLCMs. In the future, we will continue to improve the performance of the CBT-based SLCM and will update the Global LAnd Surface Satellite (GLASS) SLDR product under cloudy sky conditions. Land surface; Satellites; Spatial resolution; Land surface temperature; remote sensing; Clouds; Cloud computing; validation.; Cloud-base temperature (CBT); single-layer cloud model (SLCM); surface longwave downward radiation (SLDR); Temperature distribution
Yarahmadi, Mehran; Mahan, J. Robert; Kowsary, FarshadYarahmadi, M., J. R. Mahan, F. Kowsary, 2021: A New Approach to Inverse Boundary Design in Radiation Heat Transfer. Advances in Heat Transfer and Thermal Engineering, 377-383. doi: 10.1007/978-981-33-4765-6_65. Inverse boundary design problems in surface-to-surface radiation heat transfer occur when both the temperature and net heat flux are prescribed on some of the surfaces while neither is known on the remaining surfaces. The problem is to find the unknown surface temperatures required to produce the prescribed temperatures and net heat fluxes. This chapter presents a novel approach in which a transcendental function of position—in this case a Fourier cosine series—is used to represent the spatial distribution of the unknown fourth power of surface temperature. The problem then becomes one of the findings the Fourier coefficients and fundamental angular frequency that minimize the difference between the prescribed and calculated surface temperature distributions. The approach is shown to produce more accurate results than the classical optimization approach in a fraction of the execution time for the example of an industrial processing oven.
Ye, Shuchao; Feng, Huihui; Zou, Bin; Ding, Ying; Zhu, Sijia; Li, Feng; Dong, GuotaoYe, S., H. Feng, B. Zou, Y. Ding, S. Zhu, F. Li, G. Dong, 2021: Satellite-Based Estimation of the Influence of Land Use and Cover Change on the Surface Shortwave Radiation Budget in a Humid Basin. Remote Sensing, 13(8), 1447. doi: 10.3390/rs13081447. The surface shortwave radiation budget (Rsn) is one of the main drivers of Earth’s ecosystems and varies with atmospheric and surface conditions. Land use and cover change (LUCC) alters radiation through biogeophysical effects. However, due to the complex interactions between atmospheric and surface factors, it is very challenging to quantify the sole impacts of LUCC. Based on satellite data from the Global Land Surface Satellite (GLASS) Product and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments, this study introduces an observation-based approach for detecting LUCC influences on the Rsn by examining a humid basin over the Dongting Lake Basin, China from 2001 to 2015. Our results showed that the Rsn of the study area presented a decreasing trend due to the combined effects of LUCC and climate change. Generally, LUCC contributed −0.45 W/m2 to Rsn at the basin scale, which accounted for 2.53% of the total Rsn change. Furthermore, the LUCC contributions reached −0.69 W/m2, 0.21 W/m2, and −0.41 W/m2 in regions with land transitions of forest→grass, grass→forest, and grass→farmland, which accounted for 5.38%, −4.68%, and 2.40% of the total Rsn change, respectively. Physically, LUCC affected surface radiation by altering the surface properties. Specifically, LUCC induced albedo changes of +0.0039 at the basin scale and +0.0061, −0.0020, and +0.0036 in regions with land transitions of forest→grass, grass→forest, and grass→farmland, respectively. Our findings revealed the impact and process of LUCC on the surface radiation budget, which could support the understanding of the physical mechanisms of LUCC’s impact on ecosystems. albedo; satellite; Dongting Lake Basin; land-use and cover change; surface shortwave radiation budget
You, Cheng; Tjernström, Michael; Devasthale, AbhayYou, C., M. Tjernström, A. Devasthale, 2021: Eulerian and Lagrangian views of warm and moist air intrusions into summer Arctic. Atmospheric Research, 256, 105586. doi: 10.1016/j.atmosres.2021.105586. In this study, warm and moist air intrusions (WaMAI) over the sea sectors of Kara, Laptev, East Siberian and Beaufort from 1979 to 2018 are identified in ERA5 reanalysis and their air-mass transformation is analysed using interpolation in ERA5 and satellite products along trajectories. The analysis shows that WaMAIs, driven by blocking high-pressure systems over the respective ocean sectors, induce surface warming (11–18 W m−2) and sea ice melt from positive anomalies of net longwave radiation (5–8 W m−2) and turbulent flux (8–13 W m−2) to the surface, although the anomaly of net shortwave radiation (−9 ~ +1 W m−2) is negative. From a Lagrangian perspective, the surface energy-budget anomaly decreases linearly, while total column cloud liquid water (TCLW) increases linearly with the downstream distance from the sea-ice edge. However, the cloud radiative effects of both longwave and shortwave radiation reach an equilibrium as TCLW increases in a much lower rate beyond 7 degrees north of the sea ice edge. The boundary-layer energy-budget pattern can be categorized into two classes: radiation-dominated and turbulence-dominated, comprised of 26% and 62% WaMAIs respectively. Statistically, turbulence-dominated cases occur with 3 times stronger large-scale subsidence, and also feature a larger anomaly in net shortwave radiation. In radiation-dominated WaMAIs, stratocumulus develops more strongly and hence exerts larger longwave and shortwave forcing to the surface. In both categories, a well-mixed boundary layer deepens by 500 m along the trajectories, from the continuous turbulent mixing. Arctic climate; Boundary-layer; Trajectories; Warm and moist air intrusion
Zeitler, Lea; Corbin, Armin; Vielberg, Kristin; Rudenko, Sergei; Löcher, Anno; Bloßfeld, Mathis; Schmidt, Michael; Kusche, JürgenZeitler, L., A. Corbin, K. Vielberg, S. Rudenko, A. Löcher, M. Bloßfeld, M. Schmidt, J. Kusche, 2021: Scale Factors of the Thermospheric Density: A Comparison of Satellite Laser Ranging and Accelerometer Solutions. Journal of Geophysical Research: Space Physics, 126(12), e2021JA029708. doi: 10.1029/2021JA029708. A major problem in the precise orbit determination (POD) of satellites at altitudes below 1,000 km is the modeling of the aerodynamic drag which mainly depends on the thermospheric density and causes the largest non-gravitational acceleration. Typically, empirical thermosphere models are used to calculate density values at satellite positions but current thermosphere models cannot provide the required accuracy. Thus, unaccounted variations in the thermospheric density may lead to significantly incorrect satellite positions. For the first time, we bring together thermospheric density corrections for the NRLMSISE-00 model in terms of scale factors with a temporal resolution of 12 hr derived from satellite laser ranging (SLR) and accelerometer measurements. Whereas, the latter are in situ information given along the satellite orbit, SLR results have to be interpreted as mean values along the orbit within the underlying time interval. From their comparison, we notice a rather similar behavior with correlations of up to 80% and more depending on altitude. During high solar activity, scale factors vary around 30% at low solar activity and up to 70% at high solar activity from the value one. In addition, we found the scaled thermospheric density decreasing stronger as the modeled density of NRLMSISE-00. To check the reliability of the SLR-derived scale factors, we compare the POD result of two different software packages, namely DOGS-OC from DGFI-TUM and GROOPS from IGG Bonn. Furthermore, a validation of our estimated scale factors with respect to an external data set proofs the high quality of the obtained results.
Zhang, Caijin; Long, Di; Zhang, Yucui; Anderson, Martha C.; Kustas, William P.; Yang, YangZhang, C., D. Long, Y. Zhang, M. C. Anderson, W. P. Kustas, Y. Yang, 2021: A decadal (2008–2017) daily evapotranspiration data set of 1 km spatial resolution and spatial completeness across the North China Plain using TSEB and data fusion. Remote Sensing of Environment, 262, 112519. doi: 10.1016/j.rse.2021.112519. Daily continuous evapotranspiration (ET) estimates of 1 km spatial resolution can benefit agricultural water resources management at regional scales. Thermal infrared remote sensing-derived land surface temperature (LST) is a critical variable for ET estimation using energy balance-based models. However, missing LST information under cloudy conditions remains a long-standing barrier for spatiotemporally continuous monitoring of daily ET at regional scales. In this study, LST data of 1 km spatial resolution at 11:00 local solar time under all-weather conditions across the North China Plain (NCP) were first generated using a data fusion approach developed previously. Second, combined with the generated LST data, MODIS products, and meteorological forcing from the China Land Data Assimilation System, the Two-Source Energy Balance model (TSEB) and a temporal upscaling method were jointly used to estimate daily ET at 1 km spatial resolution across the NCP for a decade from 2008 to 2017. In particular, to better incorporate the impact of crop phenology on ET and improve the ET estimation, the fraction of greenness in TSEB was determined in terms of a leaf area index threshold during the crop growth period. Compared with observed instantaneous latent heat flux (LE) corrected for energy balance closure, the estimated LE reasonably captures inter- and intra-annual variations in LE measured at the Huailai, Daxing, Weishan, and Guantao flux towers, with R2 of 0.63–0.79. Estimated daily ET against in situ ET measurements with energy balance closure at the Huailai, Daxing, and Guantao sites showed good performance in terms of R2 greater than 0.70 and RMSE below 0.91 mm/d. These accuracies are comparable with published results, with our ET data set validated by many more observations than previous studies and featuring spatiotemporal continuity and high spatial resolution across the entire NCP for a decade. Furthermore, seasonal ET variations reflected by our product outperform two widely used global products in capturing water consumption characteristics in the winter wheat-summer maize rotation system. In terms of temporal trends, annual ET estimates across the NCP show a decreasing and then increasing trend over the past decade, which is attributed to the increased cropping intensity over the recent years reflected by an increase in leaf area index. Evapotranspiration; Land surface temperature; Data fusion; Two-source energy balance
Zhang, Chunyan; Wang, Donghai; Pang, Zihao; Zhang, Yu; Jiang, Xiaoling; Zeng, Zhilin; Wu, ZhenzhenZhang, C., D. Wang, Z. Pang, Y. Zhang, X. Jiang, Z. Zeng, Z. Wu, 2021: Large-scale dynamic, heat and moisture structures of monsoon-influenced precipitation in the East Asian monsoon rainy area. Quarterly Journal of the Royal Meteorological Society, 147(735), 1007-1030. doi: https://doi.org/10.1002/qj.3956. This study investigated large-scale dynamic structures along with heat and moisture budgets associated with monsoon-influenced precipitation over a typical rainy domain in the East Asian monsoon region. Large-scale dynamically and thermodynamically consistent forcing data based on multiple measurements were produced by a one-dimensional constrained variational analysis method. Using the forcing data, distinct characteristics of large-scale states were documented for cases of notable pre-monsoon rainfall before the South China Sea monsoon onset (SCSMO), extreme rainfall during SCSMO, and persistent strong rainfall after SCSMO. The pre-monsoon period mainly resulted from weak and discrete cloud regimes. The extreme-rain period was associated with a severe deep convective system moving from the west, and the persistent-rain period was related to moderate convective cells separated from the strong convective system over the northern South China Sea. Large-scale features including vertical velocity, wind convergence, and diabatic heating and drying were the strongest (weakest) during the extreme-rain (pre-monsoon) period. For the pre-monsoon and persistent-rain periods, the period-averaged profiles of vertical velocity and diabatic heating and drying showed a one-peak structure. However, during the extreme-rain period, a leap-forward mutation was seen in the vertical structure and magnitude of these large-scale states. The multiple peaks shown in the vertical profiles of vertical velocity and diabatic heating during the extreme-rain period may indicate various convective cloud systems co-existed. The diabatic heating profiles of extreme rainfall indicated that the first rainfall peak was related to the successive occurrence of stratiform anvils and convective clouds, while the second rainfall peak, which was most intense, was associated with shallow convective clouds, severe deep convective clouds, and detraining stratiform anvils. constrained variational analysis; heating profile; large-scale structures; monsoon-influenced precipitation; upward motion
Zhang, Rudong; Wang, Hailong; Fu, Qiang; Rasch, Philip J.; Wu, Mingxuan; Maslowski, WieslawZhang, R., H. Wang, Q. Fu, P. J. Rasch, M. Wu, W. Maslowski, 2021: Understanding the Cold Season Arctic Surface Warming Trend in Recent Decades. Geophysical Research Letters, 48(19), e2021GL094878. doi: 10.1029/2021GL094878. Whether sea-ice loss or lapse-rate feedback dominates the Arctic amplification (AA) remains an open question. Analysis of data sets based upon observations reveals a 1.11 K per decade surface warming trend in the Arctic (70°–90°N) during 1979–2020 cold season (October–February) that is five times higher than the corresponding global mean. Based on surface energy budget analysis, we show that the largest contribution (∼82%) to this cold season warming trend is attributed to changes in clear-sky downward longwave radiation. In contrast to that in Arctic summer and over tropics, a reduction in lower-tropospheric inversions plays a unique role in explaining the reduction of the downward longwave radiation associated with atmospheric nonuniform temperature and corresponding moisture changes. Our analyses also suggest that Arctic lower-tropospheric stability should be considered in conjunction with sea-ice decline during the preceding warm season to explain AA. reanalysis; energy budget; Arctic amplification; radiative feedback; Arctic inversion; sea ice loss
Zhang, Taiping; Stackhouse, Paul W.; Cox, Stephen J.; Mikovitz, J. Colleen; Long, Charles N.Zhang, T., P. W. Stackhouse, S. J. Cox, J. C. Mikovitz, C. N. Long, 2021: Addendum to figs. 10 and 11 in “Clear-sky shortwave downward flux at the earth's surface: Ground-based data vs. satellite-based data” [J. Quant. Spec. and Rad. Tran. 224 (2019) 247-260]. Journal of Quantitative Spectroscopy and Radiative Transfer, 261, 107487. doi: 10.1016/j.jqsrt.2020.107487. While the CERES input aerosol optical depth and precipitable water data are continuously available, the same parameters derived from BSRN site measurements are available only intermittently. Cloudiness disrupts the aerosol optical depth (AOD) retrieval and precipitable water (w) observation sampling. Irregularly sampled records, such as these, can cause systematic biases if the averages of the continuous data are not sampled at the same times as the observed data, as shown by high biases in Fig. 10 in our original paper. This, however, does not suggest that the CERES input aerosol optical depth and precipitable water are systematically significantly higher than ground-based observations. In this addendum, we show that when the monthly means are computed from only those CERES hourly means that have a BSRN match, then the resulting monthly means differ from BSRN-derived parameters to a much lesser extent. To be precise, the biases in the original Fig. 10 decrease 82%, 69% and 52%, respectively; the magnitudes of slopes in the original Fig. 11 decrease by 69% and 65%, respectively. Imposing a cloud fraction less than or equal to 5% further reduces AOD and w mean values but not biases. Nevertheless, the flux bias reduces from -16.9 W m−2 to -4.2 W m−2 after imposing the cloud fraction restraint relative to the RADFlux clear-sky fluxes which appear to represent the driest and clearest conditions. CERES; Solar radiation; Satellite; GEWEX SRB; RadFlux
Zhang, Yuanchong; Jin, Zhonghai; Sikand, MonikaZhang, Y., Z. Jin, M. Sikand, 2021: The Top-of-Atmosphere, Surface and Atmospheric Cloud Radiative Kernels Based on ISCCP-H Datasets: Method and Evaluation. Journal of Geophysical Research: Atmospheres, 126(24), e2021JD035053. doi: 10.1029/2021JD035053. This study aims to create observation-based cloud radiative kernel (CRK) datasets and evaluate them by direct comparison of CRK and the CRK-derived cloud feedback datasets. Based on the International Satellite Cloud Climatology Project (ISCCP) H datasets, we calculate CRKs (called ISCCP-FH or FH CRKs) as 2D joint function/histogram of cloud optical depth and cloud top pressure for shortwave (SW), longwave (LW), and their sum, Net, at the top of atmosphere (TOA), as well as, for the first time, at the surface (SFC) and in the atmosphere (ATM). With cloud fraction change (CFC) datasets from doubled-CO2 simulation and short-term observational anomalies, we derive all the TOA, SFC and ATM cloud feedback for SW, LW and Net using our CRKs.The direct comparison with modeled and observed CRKs (or cloud radiative effects), cloud feedback from previous model results and the Clouds and the Earth's Radiant Energy System products show that our CRKs and CRK-derived cloud feedback are reasonably well validated. We estimate the uncertainty for the CRK-derived cloud feedback and show that the CFC-associated uncertainty contributes >98.5% of the total cloud feedback uncertainty while CRK's is very small. Our preliminary evaluation also shows that some near-zero/small cloud feedback in the TOA-alone feedback indeed results from the compensation of sizable cloud feedback of the SFC and ATM feedback and reveals some significant surface and atmospheric cloud feedback whose sum appears insignificant in TOA-alone feedback. In addition, the atmospheric longwave cloud feedback seems to play a role in enhancing meridional atmospheric energy transport. CERES; cloud feedback; cloud radiative effects; cloud radiative kernel; cloud-type based decomposition; ISCCP-FH
Zhao, Xi; Liu, XiaohongZhao, X., X. Liu, 2021: Global Importance of Secondary Ice Production. Geophysical Research Letters, 48(11), e2021GL092581. doi: 10.1029/2021GL092581. Measured ice crystal number concentrations are often orders of magnitude higher than the number concentrations of ice nucleating particles, indicating the existence of secondary ice production (SIP) in clouds. Here, we present the first study to examine the global importance of SIP through the droplet shattering during freezing of rain, ice-ice collision fragmentation, and rime splintering, using a global climate model. Our results show that SIP happens quite uniformly in the two hemispheres and dominates the ice formation in the moderately cold clouds with temperatures warmer than −15°C. SIP decreases the global annual average liquid water path by −14.6 g m−2 (−22%), increases the ice water path by 8.7 g m−2 (23%), improving the model agreement with observations. SIP changes the global annual average shortwave, longwave, and net cloud forcing by 2.1, −1.0, and 1.1 W m−2, respectively, highlighting the importance of SIP on cloud properties on the global scale. cloud forcing; global climate model; cloud microphysics; secondary ice production
Zhao, Zhe; Li, Wei; Ciais, Philippe; Santoro, Maurizio; Cartus, Oliver; Peng, Shushi; Yin, Yi; Yue, Chao; Yang, Hui; Yu, Le; Zhu, Lei; Wang, JingmengZhao, Z., W. Li, P. Ciais, M. Santoro, O. Cartus, S. Peng, Y. Yin, C. Yue, H. Yang, L. Yu, L. Zhu, J. Wang, 2021: Fire enhances forest degradation within forest edge zones in Africa. Nature Geoscience, 14(7), 479-483. doi: 10.1038/s41561-021-00763-8. African forests suffer from severe fragmentation that further causes forest degradation near forest edges. The impact of fires used for slash-and-burn on forest edge effects remains unclear. Here, using high-resolution satellite-based forest-cover and biomass datasets, we find that edge effects extend a median distance and an interquartile range of $$0.11_{ - 0.04}^{ + 0.06}\,{\mathrm{km}}$$and $$0.15_{ - 0.05}^{ + 0.09}\,{\mathrm{km}}$$into moist and dry forests, and biomass within the forest edge zones has a carbon deficit of 4.1 PgC. Fires occurred in 52% of the forest edges and increased the carbon deficit by $$5.5_{ - 2.9}^{ + 4.3}\,{\mathrm{MgC}}\,{\mathrm{ha}^{{-1}}}$$, compared with non-fire edges, through both the direct impact of fires intruding into forests and the indirect impact of changes in the local atmospheric circulations increasing canopy dryness. If small-scale slash-and-burn practices continue, increased fragmentation during 2010–2100 will result in a carbon loss from edge effects of 0.54–4.6 PgC. Fragmentation-caused forest degradation could be avoided by implementing dedicated forest protection policies supported by satellite monitoring of forest edges.
Zhong, Bo; Ma, Yingbo; Yang, Aixia; Wu, JunjunZhong, B., Y. Ma, A. Yang, J. Wu, 2021: Radiometric Performance Evaluation of FY-4A/AGRI Based on Aqua/MODIS. Sensors, 21(5), 1859. doi: 10.3390/s21051859. Fengyun-4A (FY-4A) is the first satellite of the Chinese second-generation geostationary orbit meteorological satellites (FY-4). The Advanced Geostationary Radiation Imager (AGRI), onboard FY-4A does not load with high-precision calibration facility in visible and near infrared (VNIR) channel. As a consequence, it is necessary to comprehensively evaluate its radiometric performance and quantitatively describe the attenuation while using its VNIR data. In this paper, the radiometric performance at VNIR channels of FY-4A/AGRI is evaluated based on Aqua/MODIS data using the deep convective cloud (DCC) target. In order to reduce the influence of view angle and spectral response difference, the bi-directional reflectance distribution function (BRDF) correction and spectral matching have been performed. The evaluation result shows the radiometric performance of FY-4A/AGRI: (1) is less stable and with obvious fluctuations; (2) has a lower radiation level because of 24.99% lower compared with Aqua/MODIS; 3) has a high attenuation with 9.11% total attenuation over 2 years and 4.0% average annual attenuation rate. After the evaluation, relative radiometric normalization between AGRI and MODIS in VNIR channel is performed and the procedure is proved effective. This paper proposed a more reliable reference for the quantitative applications of FY-4A data. DCC; Aqua/MODIS; FY-4A/AGRI; radiometric performance; VNIR
Zhou, Chen; Zelinka, Mark D.; Dessler, Andrew E.; Wang, MinghuaiZhou, C., M. D. Zelinka, A. E. Dessler, M. Wang, 2021: Greater committed warming after accounting for the pattern effect. Nature Climate Change, 11(2), 132-136. doi: 10.1038/s41558-020-00955-x. Our planet’s energy balance is sensitive to spatial inhomogeneities in sea surface temperature and sea ice changes, but this is typically ignored in climate projections. Here, we show the energy budget during recent decades can be closed by combining changes in effective radiative forcing, linear radiative damping and this pattern effect. The pattern effect is of comparable magnitude but opposite sign to Earth’s net energy imbalance in the 2000s, indicating its importance when predicting the future climate on the basis of observations. After the pattern effect is accounted for, the best-estimate value of committed global warming at present-day forcing rises from 1.31 K (0.99–2.33 K, 5th–95th percentile) to over 2 K, and committed warming in 2100 with constant long-lived forcing increases from 1.32 K (0.94–2.03 K) to over 1.5 K, although the magnitude is sensitive to sea surface temperature dataset. Further constraints on the pattern effect are needed to reduce climate projection uncertainty.
Zhou, Xiaoli; Atlas, Rachel; McCoy, Isabel L.; Bretherton, Christopher S.; Bardeen, Charles; Gettelman, Andrew; Lin, Pu; Ming, YiZhou, X., R. Atlas, I. L. McCoy, C. S. Bretherton, C. Bardeen, A. Gettelman, P. Lin, Y. Ming, 2021: Evaluation of cloud and precipitation simulations in CAM6 and AM4 using observations over the Southern Ocean. Earth and Space Science, (In Press). doi: https://doi.org/10.1029/2020EA001241. This study uses cloud and radiative properties collected from in-situ and remote sensing instruments during two coordinated campaigns over the Southern Ocean between Tasmania and Antarctica in January-February 2018 to evaluate the simulations of clouds and precipitation in nudged-meteorology simulations with the CAM6 and AM4 global climate models sampled at the times and locations of the observations. Fifteen SOCRATES research flights sampled cloud water content, cloud droplet number concentration, and particle size distributions in mixed-phase boundary-layer clouds at temperatures down to -25 C. The six-week CAPRICORN2 research cruise encountered all cloud regimes across the region. Data from vertically-pointing 94 GHz radars deployed was compared with radar-simulator output from both models. Satellite data was compared with simulated top-of-atmosphere (TOA) radiative fluxes. Both models simulate observed cloud properties fairly well within the variability of observations. Cloud base and top in both models are generally biased low. CAM6 overestimates cloud occurrence and optical thickness while cloud droplet number concentrations are biased low, leading to excessive TOA reflected shortwave radiation. In general, low clouds in CAM6 precipitate at the same frequency but are more homogeneous compared to observations. Deep clouds are better simulated but produce snow too frequently. AM4 underestimates cloud occurrence but overestimates cloud optical thickness even more than CAM6, causing excessive outgoing longwave radiation fluxes but comparable reflected shortwave radiation. AM4 cloud droplet number concentrations match observations better than CAM6. Precipitating low and deep clouds in AM4 have too little snow. Further investigation of these microphysical biases is needed for both models.
Zhou, Xiaoli; Zhang, Jianhao; Feingold, GrahamZhou, X., J. Zhang, G. Feingold, 2021: On the Importance of Sea Surface Temperature for Aerosol-Induced Brightening of Marine Clouds and Implications for Cloud Feedback in a Future Warmer Climate. Geophysical Research Letters, 48(24), e2021GL095896. doi: 10.1029/2021GL095896. Marine low clouds are one of the greatest sources of uncertainty for climate projection. We present an observed climatology of cloud albedo susceptibility to cloud droplet number concentration perturbations (S0) with changing sea surface temperature (SST) and estimated inversion strength for single-layer warm clouds over the North Atlantic Ocean, using eight years of satellite and reanalysis data. The key findings are that SST has a dominant control on S0 in the presence of co-varying synoptic conditions and aerosol perturbations. Regions conducive to aerosol-induced darkening (brightening) clouds occur with high (low) local SST. Higher SST significantly hastens cloud-top evaporation with increasing aerosol loading, by accelerating entrainment and facilitating entrainment drying. In a global-warming-like scenario where aerosol loading is reduced, less cloud darkening is expected, mainly as a result of reduced entrainment drying. Our results imply a less positive low-cloud liquid water path feedback in a warmer climate with decreasing aerosol loading. Climatology; North Atlantic Ocean; marine boundary layer clouds; A-Train satellite measurements; Cloud aerosol interaction; low-cloud liquid water path feedback
Zhu, Fuxin; Li, Xin; Qin, Jun; Yang, Kun; Cuo, Lan; Tang, Wenjun; Shen, ChaopengZhu, F., X. Li, J. Qin, K. Yang, L. Cuo, W. Tang, C. Shen, 2021: Integration of Multisource Data to Estimate Downward Longwave Radiation Based on Deep Neural Networks. IEEE Transactions on Geoscience and Remote Sensing, 1-15. doi: 10.1109/TGRS.2021.3094321. Downward longwave radiation (DLR) at the surface is a key variable of interest in fields, such as hydrology and climate research. However, existing DLR estimation methods and DLR products are still problematic in terms of both accuracy and spatiotemporal resolution. In this article, we propose a deep convolutional neural network (DCNN)-based method to estimate hourly DLR at 5-km spatial resolution from top of atmosphere (TOA) brightness temperature (BT) of the Himawari-8/Advanced Himawari Imager (AHI) thermal channels, combined with near-surface air temperature and dew point temperature of ERA5 and elevation data. Validation results show that the DCNN-based method outperforms popular random forest and multilayer perceptron-based methods and that our proposed scheme integrating multisource data outperforms that only using remote sensing TOA observations or surface meteorological data. Compared with state-of-the-art CERES-SYN and ERA5-land DLR products, the estimated DLR by our proposed DCNN-based method with physical multisource inputs has higher spatiotemporal resolution and accuracy, with correlation coefficient (CC) of 0.95, root-mean-square error (RMSE) of 17.2 W/m², and mean bias error (MBE) of -0.8 W/m² in the testing period on the Tibetan Plateau. Land surface; Atmospheric modeling; Ocean temperature; Spatial resolution; Himawari-8; Clouds; Temperature distribution; Deep convolutional neural network (DCNN); downward longwave radiation (DLR); Estimation; Tibetan Plateau (TP).
Zhu, Yingli; Mitchum, Gary T.; Thompson, Philip R.; Lagerloef, Gary S. E.Zhu, Y., G. T. Mitchum, P. R. Thompson, G. S. E. Lagerloef, 2021: Diagnosis of Large-Scale, Low-Frequency Sea Level Variability in the Northeast Pacific Ocean. Journal of Geophysical Research: Oceans, 126(5), e2020JC016682. doi: https://doi.org/10.1029/2020JC016682. Earlier studies in the Northeast Pacific (NEP) suggest that the local and remote sea level responses are important for the large-scale, low-frequency sea level variability, but the relative importance of the two processes remains unclear. In this study, we develop a novel sea level model driven by wind, buoyancy and eddy forcing to examine their relative roles in the NEP. Based on the new model, a diagnostic equation for sea level that is an alternative to the conventional method of characteristics is formed. The wind, buoyancy and eddy forcing account for the sea level variability in different regions. Sea level variability is primarily controlled by the wind forcing in the central to the northeast of the NEP, by the local buoyancy forcing in the southeast region between 210°E and 230°E, and by the eddy forcing in the southwest of the NEP. In addition, the diagnosis demonstrates that the local sea level response is more important than the remote response over most of the NEP, while the remote sea level response could play an important role in the southwest portion of the NEP. wind forcing; Northeast Pacific; buoyancy forcing; eddy forcing; local sea level response; remote sea level response
Zou, Xun; Bromwich, David H.; Montenegro, Alvaro; Wang, Sheng-Hung; Bai, LeshengZou, X., D. H. Bromwich, A. Montenegro, S. Wang, L. Bai, 2021: Major surface melting over the Ross Ice Shelf part II: Surface energy balance. Quarterly Journal of the Royal Meteorological Society, 147(738), 2895-2916. doi: 10.1002/qj.4105. The West Antarctic climate is under the combined impact of synoptic and regional drivers. Regional factors have contributed to more frequent surface melting with a similar pattern recently, which accelerates ice loss and favors global sea-level rise. Part I of this research identified and quantified the two leading drivers of Ross Ice Shelf (RIS) melting, viz. foehn effect and direct marine air advection, based on Polar WRF (PWRF) simulations. In this article (Part II), the impact of clouds and the pattern of surface energy balance (SEB) during melting are analyzed, as well as the relationship among these three factors. In general, net shortwave radiation dominates the surface melting with a daily mean value above 100 W·m−2. Foehn clearance and decreasing surface albedo respectively increase the downward shortwave radiation and increase the absorbed shortwave radiation, significantly contributing to surface melting in areas such as western Marie Byrd Land. Also, extensive downward longwave radiation caused by low-level liquid cloud favors the melting expansion over the middle and coastal RIS. With significant moisture transport occurring over more than 40% of the time during the melting period, the impact from net radiation can be amplified. Moreover, frequent foehn cases can enhance the turbulent mixing on the leeside. With a Froude number (Fr) around 1 or slightly larger, fast downdrafts or reversed wind flows can let the warm foehn air penetrate down to the surface with up to 20 W·m−2 in sensible heat flux transfer to the ground. However, when the Froude number is close to infinity with breaking waves on the leeside, the contribution of turbulence to the surface warming is reduced. With better understanding of the regional factors for the surface melting, prediction of the future stability of West Antarctic ice shelves can be improved. clouds; surface energy balance; polar WRF; West Antarctic surface melting
## 2020
Abera, Temesgen Alemayehu; Heiskanen, Janne; Pellikka, Petri K. E.; Maeda, Eduardo EijiAbera, T. A., J. Heiskanen, P. K. E. Pellikka, E. E. Maeda, 2020: Impact of rainfall extremes on energy exchange and surface temperature anomalies across biomes in the Horn of Africa. Agricultural and Forest Meteorology, 280, 107779. doi: 10.1016/j.agrformet.2019.107779. Precipitation extremes have a strong influence on the exchange of energy and water between the land surface and the atmosphere. Although the Horn of Africa has faced recurrent drought and flood events in recent decades, it is still unclear how these events impact energy exchange and surface temperature across different ecosystems. Here, we analyzed the impact of precipitation extremes on spectral albedo (total shortwave, visible, and near-infrared (NIR) broadband albedos), energy balance, and surface temperature in four natural vegetation types: forest, savanna, grassland, and shrubland. We used remotely sensed observations of surface biophysical properties and climate from 2001 to 2016. Our results showed that, in forests and savannas, precipitation extremes led to divergent spectral changes in visible and NIR albedos, which cancelled each other limiting shortwave albedo changes. An exception to this pattern was observed in shrublands and grasslands, where both visible and NIR albedo increased during drought events. Given that shrublands and grasslands occupy a large fraction of the Horn of Africa (52%), our results unveil the importance of these ecosystems in driving the magnitude of shortwave radiative forcing in the region. The average regional shortwave radiative forcing during drought events (−0.64 W m−2, SD 0.11) was around twice that of the extreme wet events (0.33 W m−2, SD 0.09). Such shortwave forcing, however, was too small to influence the surface–atmosphere coupling. In contrast, the surface feedback through turbulent flux changes was strong across vegetation types and had a significant (P CERES; MODIS; Albedo; Energy exchange; Land surface temperature; Precipitation extremes
Ajoku, Osinachi; Norris, Joel R.; Miller, Arthur J.Ajoku, O., J. R. Norris, A. J. Miller, 2020: Observed monsoon precipitation suppression caused by anomalous interhemispheric aerosol transport. Climate Dynamics, 54(1), 1077-1091. doi: 10.1007/s00382-019-05046-y. This study uses observations and atmospheric reanalysis products in order to understand the impacts of smoke aerosols advected from the Southern Hemisphere on the dynamics of the West African monsoon. Seasonal biomass burning and resulting aerosol emissions have been well documented to affect regional weather patterns, especially low-level convection. Out of all monsoon months, precipitation shows the most variability over land during August, in which anomalous smoke aerosol values can increase (decrease) by 33% (29%) in the Northern Gulf of Guinea and precipitation can decrease (increase) by up to ~ 2.5 mm day−1 (~ 3 mm day−1) along the West African monsoon region accounting for a 17% (18%) change in precipitation. Smoke aerosols produced by biomass burning occurring near Central Africa are advected towards the Gulf of Guinea at elevations around the 850 hPa level. Satellite observations show an increase (decrease) in cloud fraction and optical depth below (above) the 300-hPa level in the Gulf of Guinea and along the West African coastline along with concurrent decreases (increases) in cloud droplet radius during dirty (clean) aerosol episodes. Additional observations of shortwave radiation quantify changes in cloud coverage and monsoon dynamics. On average, reductions in surface shortwave radiation of ~ 10–15 W m−2 occur over the Gulf of Guinea during increased aerosol transport, with aerosols accounting for ~ 33–50% of that reduction. Reductions in shortwave radiation are associated with decreased convective available potential energy (CAPE). This demonstrates that increased transport of aerosols perturbs surface radiation, convection in the lower troposphere and eventually cloud coverage, potentially leading to the observed monsoon precipitation suppression. In a broader social context, this region houses 200 million people and thus understanding these climate patterns may carry great importance.
Amos, Helen M.; Starke, Matthew J.; Rogerson, Tina M.; Robles, Marilé Colón; Andersen, Travis; Boger, Rebecca; Campbell, Brian A.; Low, Russanne D.; Nelson, Peder; Overoye, David; Taylor, Jessica E.; Weaver, Kristen L.; Ferrell, Trena M.; Kohl, Holli; Schwerin, Theresa G.Amos, H. M., M. J. Starke, T. M. Rogerson, M. Robles, . Colón, T. Andersen, R. Boger, B. A. Campbell, R. D. Low, P. Nelson, D. Overoye, J. E. Taylor, K. L. Weaver, T. M. Ferrell, H. Kohl, T. G. Schwerin, 2020: GLOBE Observer Data: 2016–2019. Earth and Space Science, 7(8), e2020EA001175. doi: 10.1029/2020EA001175. This technical report summarizes the GLOBE Observer data set from 1 April 2016 to 1 December 2019. GLOBE Observer is an ongoing NASA-sponsored international citizen science project that is part of the larger Global Learning and Observations to Benefit the Environment (GLOBE) Program, which has been in operation since 1995. GLOBE Observer has the greatest number of participants and geographic coverage of the citizen science projects in the Earth Science Division at NASA. Participants use the GLOBE Observer mobile app (launched in 2016) to collect atmospheric, hydrologic, and terrestrial observations. The app connects participants to satellite observations from Aqua, Terra, CALIPSO, GOES, Himawari, and Meteosat. Thirty-eight thousand participants have contributed 320,000 observations worldwide, including 1,000,000 georeferenced photographs. It would take an individual more than 13 years to replicate this effort. The GLOBE Observer app has substantially increased the spatial extent and sampling density of GLOBE measurements and more than doubled the number of measurements collected through the GLOBE Program. GLOBE Observer data are publicly available (at observer.globe.gov). cloud cover; citizen science; global data set; land cover; mosquitoes; tree height
Annamalai, H.Annamalai, H., 2020: ENSO Precipitation Anomalies along the Equatorial Pacific: Moist Static Energy Framework Diagnostics. J. Climate, 33(21), 9103-9127. doi: 10.1175/JCLI-D-19-0374.1.
Attada, Raju; Dasari, Hari Prasad; Kunchala, Ravi Kumar; Langodan, Sabique; Niranjan Kumar, Kondapalli; Knio, Omar; Hoteit, IbrahimAttada, R., H. P. Dasari, R. K. Kunchala, S. Langodan, K. Niranjan Kumar, O. Knio, I. Hoteit, 2020: Evaluating Cumulus Parameterization Schemes for the Simulation of Arabian Peninsula Winter Rainfall. J. Hydrometeor., 21(5), 1089-1114. doi: 10.1175/JHM-D-19-0114.1. This study investigates the sensitivity of winter seasonal rainfall over the Arabian Peninsula (AP) to different convective physical parameterization schemes using a high-resolution WRF Model. Three different parameterization schemes, Kain–Fritch (KF), Betts–Miller–Janjić (BMJ), and Grell–Freitas (GF), are used in winter simulations from 2001 to 2016. Results from seasonal simulations suggest that simulated AP winter rainfall with KF is in best agreement with observed rainfall in terms of spatial distribution and intensity. Higher spatial correlation coefficients and fewer biases with observations are also obtained with KF. In addition, the regional moisture transport, cloud distribution, and cloud microphysical responses are better simulated by KF. The AP low-level circulation, characterized by the Arabian anticyclone, is well captured by KF and BMJ, but its position is displaced in GF. KF is furthermore successful at simulating the moisture distribution in the lower atmosphere and atmospheric water plumes in the middle troposphere. The higher skill of rainfall simulation with the KF (and to some extent BMJ) is attributed to a better representation of the Arabian anticyclone and subtropical westerly jet, which guides the upper tropospheric synoptic transients and moisture. In addition, the vertical profile of diabatic heating from KF is in better agreement with the observations. Discrepancies in representing the diabatic heating profile by BMJ and GF show discrepancies in instability and in turn precipitation biases. Our results indicate that the selection of subgrid convective parameterization in a high-resolution atmospheric model over the AP is an important factor for accurate regional rainfall simulations.
Avtar, Ram; Komolafe, Akinola Adesuji; Kouser, Asma; Singh, Deepak; Yunus, Ali P.; Dou, Jie; Kumar, Pankaj; Gupta, Rajarshi Das; Johnson, Brian Alan; Thu Minh, Huynh Vuong; Aggarwal, Ashwani Kumar; Kurniawan, Tonni AgustionoAvtar, R., A. A. Komolafe, A. Kouser, D. Singh, A. P. Yunus, J. Dou, P. Kumar, R. D. Gupta, B. A. Johnson, H. V. Thu Minh, A. K. Aggarwal, T. A. Kurniawan, 2020: Assessing sustainable development prospects through remote sensing: A review. Remote Sensing Applications: Society and Environment, 20, 100402. doi: 10.1016/j.rsase.2020.100402. The Earth's ecosystems face severe environmental stress from unsustainable socioeconomic development linked to population growth, urbanization, and industrialization. Governments worldwide are interested in sustainability measures to address these issues. Remote sensing allows for the measurement, integration, and presentation of useful information for effective decision-making at various temporal and spatial scales. Scientists and decision-makers have endorsed extensive use of remote sensing to bridge gaps among disciplines and achieve sustainable development. This paper presents an extensive review of remote sensing technology used to support sustainable development efforts, with a focus on natural resource management and assessment of natural hazards. We further explore how remote sensing can be used in a cross-cutting, interdisciplinary manner to support decision-making aimed at addressing sustainable development challenges. Remote sensing technology has improved significantly in terms of sensor resolution, data acquisition time, and accessibility over the past several years. This technology has also been widely applied to address key issues and challenges in sustainability. Furthermore, an evaluation of the suitability and limitations of various satellite-derived indices proposed in the literature for assessing sustainable development goals showed that these older indices still perform reasonably well. Nevertheless, with advancements in sensor radiometry and resolution, they were less exploited and new indices are less explored. Decision support system; Indices; Natural hazards; Natural resource management; Sustainability
Baba, YuyaBaba, Y., 2020: Shallow convective closure in a spectral cumulus parameterization. Atmospheric Research, 233, 104707. doi: 10.1016/j.atmosres.2019.104707. A shallow convective closure (shallow closure) was introduced in a spectral cumulus parameterization (spectral scheme), and the validity was evaluated using an atmospheric general circulation model (AGCM) and Atmospheric Model Intercomparison Project (AMIP) experiments. The spectral scheme with shallow closure improved model simulated climatology and variability as compared with the spectral scheme only. The shallow closure enhanced shallow convection, leading to an improvements in dry bias in the tropics and cold bias in the extratropics. The simulated interannual variabilities were comparable regardless of the shallow closure; however, intraseasonal variability was greatly improved with the shallow closure. This is because detrainment from shallow convection during development of the Madden-Julian oscillation (MJO) contributes to supplying moisture in organized convection, and the spectral scheme with shallow closure was able to simulate this contribution well. Climatology; Atmospheric variability; Convection scheme; Convective closure; Shallow convection
Baba, Yuya; Giorgetta, Marco A.Baba, Y., M. A. Giorgetta, 2020: Tropical Variability Simulated in ICON-A With a Spectral Cumulus Parameterization. Journal of Advances in Modeling Earth Systems, 12(1), e2019MS001732. doi: 10.1029/2019MS001732. We implemented a spectral cumulus parameterization based on a cloud-resolving model (SC scheme) in the icosahedral nonhydrostatic atmospheric model (ICON-A). We compared the resulting simulated climatology and tropical variability with results from the standard version of ICON-A using a variant of the Tiedtke-Nordeng scheme (TK scheme) using observational and reanalysis data. The climatological errors of the SC scheme were similar to those of the TK scheme, but several biases, such as properties of meridional winds and precipitation pattern in the western Pacific, were much improved. For tropical variability, we found that the SC scheme improved the interannual response of the precipitation in the western Pacific and was able to simulate Madden-Julian oscillation (MJO) features much better than the TK scheme. We investigated the reason for the better simulation of the MJO using composite analysis and column process analysis for moisture. Our results suggest that the entrainment parameterization of the SC scheme is necessary to reproduce the MJO; however, spectral representation and improved convective closure are also found to contribute for better MJO simulation. These parameterizations improved moisture supply from low-level clouds and cloud mass flux which were needed to sustain the MJO. atmospheric general circulation model; convection scheme; tropical variability
Back, Seung-Yoon; Han, Ji-Young; Son, Seok-WooBack, S., J. Han, S. Son, 2020: Modeling Evidence of QBO-MJO Connection: A Case Study. Geophysical Research Letters, 47(20), e2020GL089480. doi: 10.1029/2020GL089480. The boreal winter Madden-Julian Oscillation (MJO) is modulated by the Quasi-Biennial Oscillation (QBO). The MJO becomes relatively strong during the easterly QBO (EQBO) winters but weak during the westerly QBO (WQBO) winters. To better understand their relationship, a set of WRF model experiments is conducted with varying lateral boundary conditions. The MJO event in December 2007, during EQBO winter, is chosen as a reference case. The control experiment qualitatively reproduces the observed MJO. When the lateral boundary conditions are switched with those of WQBO or strong WQBO winters, the MJO becomes weak over the Maritime Continent. All eight ensemble members exhibit enhanced outgoing longwave radiation and reduced precipitation from EQBO to WQBO, and to strong WQBO conditions, although the magnitude of changes is smaller than observations. This result, one of the first mesoscale modeling evidences of the QBO-MJO connection, suggests that the MJO is at least partly modulated by the QBO. tropics; Madden-Julian Oscillation; Quasi-Biennial Oscillation
Baek, Eun-Hyuk; Kim, Joo-Hong; Park, Sungsu; Kim, Baek-Min; Jeong, Jee-HoonBaek, E., J. Kim, S. Park, B. Kim, J. Jeong, 2020: Impact of poleward heat and moisture transports on Arctic clouds and climate simulation. Atmospheric Chemistry and Physics, 20(5), 2953-2966. doi: 10.5194/acp-20-2953-2020. Abstract. Many general circulation models (GCMs) have difficulty simulating Arctic clouds and climate, causing substantial inter-model spread. To address this issue, two Atmospheric Model Intercomparison Project (AMIP) simulations from the Community Atmosphere Model version 5 (CAM5) and Seoul National University (SNU) Atmosphere Model version 0 (SAM0) with a unified convection scheme (UNICON) are employed to identify an effective mechanism for improving Arctic cloud and climate simulations. Over the Arctic, SAM0 produced a larger cloud fraction and cloud liquid mass than CAM5, reducing the negative Arctic cloud biases in CAM5. The analysis of cloud water condensation rates indicates that this improvement is associated with an enhanced net condensation rate of water vapor into the liquid condensate of Arctic low-level clouds, which in turn is driven by enhanced poleward transports of heat and moisture by the mean meridional circulation and transient eddies. The reduced Arctic cloud biases lead to improved simulations of surface radiation fluxes and near-surface air temperature over the Arctic throughout the year. The association between the enhanced poleward transports of heat and moisture and increase in liquid clouds over the Arctic is also evident not only in both models, but also in the multi-model analysis. Our study demonstrates that enhanced poleward heat and moisture transport in a model can improve simulations of Arctic clouds and climate.
Bai, Heming; Wang, Minghuai; Zhang, Zhibo; Liu, YawenBai, H., M. Wang, Z. Zhang, Y. Liu, 2020: Synergetic Satellite Trend Analysis of Aerosol and Warm Cloud Properties ver Ocean and Its Implication for Aerosol-Cloud Interactions. Journal of Geophysical Research: Atmospheres, 125(6), e2019JD031598. doi: 10.1029/2019JD031598. Decadal-scale trends in aerosol and cloud properties provide important ways for understanding aerosol-cloud interactions. In this paper, by using MODIS products (2003–2017), we analyze synergetic trends in aerosol properties and warm cloud properties over global ocean. Cloud droplet number concentration (CDNC) and aerosol parameters (aerosol optical depth, angstrom exponent, and aerosol index) show consistent decreasing trend over East Coast of the United States (EUS), west coast of Europe (WEU), and east coast of China (EC), and no significant trend in liquid water path is found over these regions during the period 2003–2017. Over regions with significant long-term trends of aerosol loading and CDNC (e.g., EUS and WEU), the sensitivity of CDNC to aerosol loading based on the long-term trend is closer to those derived from ground and aircraft observations and larger than those derived from instantaneous satellite observations, providing an alternative way for quantifying aerosol-cloud interactions. A clear shift in the normalized probability density function of CDNC between the first 5 years (2003–2007) and the last 5 years (2013–2017) is found, with a decrease of around 50% in the occurrence frequency of high CDNC (>400 cm−3) over EUS and WEU. The relative variances of cloud droplet effective radius generally decrease with decreasing aerosol loading, providing large-scale evidence for the effects of anthropogenic aerosols on the dispersion of cloud droplet size distribution. The long-term satellite data sets provide great opportunities for quantifying aerosol-cloud interactions and further confronting these interactions in climate models in the future.
Barpanda, Pragallva; Shaw, Tiffany A.Barpanda, P., T. A. Shaw, 2020: Surface fluxes modulate the seasonality of zonal-mean storm tracks. J. Atmos. Sci., 77(2), 753–779. doi: 10.1175/JAS-D-19-0139.1. The observed zonal-mean extratropical storm tracks exhibit distinct hemispheric seasonality. Previously, the moist static energy (MSE) framework was used diagnostically to show that shortwave absorption (insolation) dominates seasonality but surface heat fluxes damp seasonality in the Southern Hemisphere (SH) and amplify it in the Northern Hemisphere (NH). Here we establish the causal role of surface fluxes (ocean energy storage), which affect surface heat fluxes, by varying the mixed layer depth (d) in zonally-symmetric 1) slab-ocean aquaplanet simulations with zero ocean energy transport and 2) Energy Balance Model (EBM) simulations. Using a scaling analysis we define a critical mixed layer depth (dc) and hypothesize 1) large mixed layer depths (d > dc) produce surface heat fluxes that are out of phase with shortwave absorption resulting in small storm track seasonality and 2) small mixed layer depths (d < dc) produce surface heat fluxes that are in phase with shortwave absorption resulting in large storm track seasonality. The aquaplanet simulations confirm the large mixed layer depth hypothesis and yield a useful idealization of the SH storm track. However, the small mixed layer depth hypothesis fails to account for the large contribution of the Ferrel cell and atmospheric storage. The small mixed layer limit does not yield a useful idealization of the NH storm track because the seasonality of the Ferrel cell contribution is opposite to the stationary eddy contribution in the NH. Varying the mixed layer depth in an EBM qualitatively supports the aquaplanet results.
Bauer, Susanne E.; Tsigaridis, Kostas; Faluvegi, Greg; Kelley, Maxwell; Lo, Ken K.; Miller, Ron L.; Nazarenko, Larissa; Schmidt, Gavin A.; Wu, JingboBauer, S. E., K. Tsigaridis, G. Faluvegi, M. Kelley, K. K. Lo, R. L. Miller, L. Nazarenko, G. A. Schmidt, J. Wu, 2020: Historical (1850-2014) aerosol evolution and role on climate forcing using the GISS ModelE2.1 contribution to CMIP6. Journal of Advances in Modeling Earth Systems, 12(8), e2019MS001978. doi: 10.1029/2019MS001978. The Earth’s climate is rapidly changing. Over the past centuries, aerosols, via their ability to absorb or scatter solar radiation and alter clouds, played an important role in counterbalancing some of the greenhouse gas (GHG) caused global warming. The multi-century anthropogenic aerosol cooling effect prevented present-day climate from reaching even higher surface air temperatures and subsequent more dramatic climate impacts. Trends in aerosol concentrations and optical depth show that in many polluted regions such as Europe and the United States of America, aerosol precursor emissions decreased back to levels of the 1950s. More recent polluting countries such as China may have reached a turning point in recent years as well, while India still follows an upward trend. Here we study aerosol trends in the CMIP6 simulations of the GISS ModelE2.1 climate model using a fully coupled atmosphere composition configuration, including interactive gas-phase chemistry, and either an aerosol microphysical (MATRIX) or a mass-based (OMA) aerosol module. Results show that whether global aerosol radiative forcing is already declining depends on the aerosol scheme used. Using the aerosol microphysical scheme, where the aerosol system reacts more strongly to the trend in sulfur dioxide (SO2) emissions, global peak direct aerosol forcing was reached in the 1980’s, whereas the mass-based scheme simulates peak direct aerosol forcing around 2010. aerosol microphysics; Aerosol Forcing; CMIP6 historical simulation; GISS model
Berry, Elizabeth; Mace, Gerald G.; Gettelman, AndrewBerry, E., G. G. Mace, A. Gettelman, 2020: Using A-Train Observations to Evaluate East Pacific Cloud Occurrence and Radiative Effects in the Community Atmosphere Model. J. Climate, 33(14), 6187-6203. doi: 10.1175/JCLI-D-19-0870.1.
Bock, L.; Lauer, A.; Schlund, M.; Barreiro, M.; Bellouin, N.; Jones, C.; Meehl, G. A.; Predoi, V.; Roberts, M. J.; Eyring, V.Bock, L., A. Lauer, M. Schlund, M. Barreiro, N. Bellouin, C. Jones, G. A. Meehl, V. Predoi, M. J. Roberts, V. Eyring, 2020: Quantifying Progress Across Different CMIP Phases With the ESMValTool. Journal of Geophysical Research: Atmospheres, 125(21), e2019JD032321. doi: 10.1029/2019JD032321. More than 40 model groups worldwide are participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6), providing a new and rich source of information to better understand past, present, and future climate change. Here, we use the Earth System Model Evaluation Tool (ESMValTool) to assess the performance of the CMIP6 ensemble compared to the previous generations CMIP3 and CMIP5. While CMIP5 models did not capture the observed pause in the increase in global mean surface temperature between 1998 and 2013, the historical CMIP6 simulations agree well with the observed recent temperature increase, but some models have difficulties in reproducing the observed global mean surface temperature record of the second half of the twentieth century. While systematic biases in annual mean surface temperature and precipitation remain in the CMIP6 multimodel mean, individual models and high-resolution versions of the models show significant reductions in many long-standing biases. Some improvements are also found in the vertical temperature, water vapor, and zonal wind speed distributions, and root-mean-square errors for selected fields are generally smaller with reduced intermodel spread and higher average skill in the correlation patterns relative to observations. An emerging property of the CMIP6 ensemble is a higher effective climate sensitivity with an increased range between 2.3 and 5.6 K. A possible reason for this increase in some models is improvements in cloud representation resulting in stronger shortwave cloud feedbacks than in their predecessor versions. climate model; evaluation; CMIP
Bony, S.; Semie, A.; Kramer, R. J.; Soden, B.; Tompkins, A. M.; Emanuel, K. A.Bony, S., A. Semie, R. J. Kramer, B. Soden, A. M. Tompkins, K. A. Emanuel, 2020: Observed Modulation of the Tropical Radiation Budget by Deep Convective Organization and Lower-Tropospheric Stability. AGU Advances, 1(3), e2019AV000155. doi: 10.1029/2019AV000155. This study analyzes the observed monthly deseasonalized and detrended variability of the tropical radiation budget and suggests that variations of the lower-tropospheric stability and of the spatial organization of deep convection both strongly contribute to this variability. Satellite observations show that on average over the tropical belt, when deep convection is more aggregated, the free troposphere is drier, the deep convective cloud coverage is less extensive, and the emission of heat to space is increased; an enhanced aggregation of deep convection is thus associated with a radiative cooling of the tropics. An increase of the tropical-mean lower-tropospheric stability is also coincident with a radiative cooling of the tropics, primarily because it is associated with more marine low clouds and an enhanced reflection of solar radiation, although the free-tropospheric drying also contributes to the cooling. The contributions of convective aggregation and lower-tropospheric stability to the modulation of the radiation budget are complementary, largely independent of each other, and equally strong. Together, they account for more than sixty percent of the variance of the tropical radiation budget. Satellite observations are thus consistent with the suggestion from modeling studies that the spatial organization of deep convection substantially influences the radiative balance of the Earth. This emphasizes the importance of understanding the factors that control convective organization and lower-tropospheric stability variations, and the need to monitor their changes as the climate warms. radiation budget; tropical variability; convective organization; tropospheric stability
Bony, Sandrine; Schulz, Hauke; Vial, Jessica; Stevens, BjornBony, S., H. Schulz, J. Vial, B. Stevens, 2020: Sugar, Gravel, Fish and Flowers: Dependence of Mesoscale Patterns of Trade-wind Clouds on Environmental Conditions. Geophysical Research Letters, 47(7), e2019GL085988. doi: 10.1029/2019GL085988. Trade-wind clouds exhibit a large diversity of spatial organizations at the mesoscale. Over the tropical western Atlantic, a recent study has visually identified four prominent mesoscale patterns of shallow convection, referred to as Flowers, Fish, Gravel and Sugar. We show that these four patterns can be identified objectively from satellite observations by analyzing the spatial distribution of infrared brightness temperatures. By applying this analysis to 19 years of data, we examine relationships between cloud patterns and large-scale environmental conditions. This investigation reveals that on daily and interannual timescales, the near-surface wind speed and the strength of the lower-tropospheric stability discriminate the occurrence of the different organization patterns. These results, combined with the tight relationship between cloud patterns, low-level cloud amount and cloud-radiative effects, suggest that the mesoscale organization of shallow clouds might change under global warming. The role of shallow convective organization in determining low-cloud feedback should thus be investigated. low-cloud feedback; mesoscale organization; shallow convection; tradewind clouds
Bosilovich, Michael G.; Robertson, Franklin R.; Stackhouse, Paul W.Bosilovich, M. G., F. R. Robertson, P. W. Stackhouse, 2020: El Niño–Related Tropical Land Surface Water and Energy Response in MERRA-2. J. Climate, 33(3), 1155-1176. doi: 10.1175/JCLI-D-19-0231.1. Although El Niño events each have distinct evolutionary character, they typically provide systematic large-scale forcing for warming and increased drought frequency across the tropical continents. We assess this response in the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), reanalysis and in a 10-member-model Atmospheric Model Intercomparison Project (AMIP) ensemble. The lagged response (3–4 months) of mean tropical land temperature to El Niño warming in the Pacific Ocean is well represented. MERRA-2 reproduces the patterns of precipitation in the tropical regions, and the AMIP ensemble reproduces some regional responses that are similar to those observed and some regions that are not simulating the response well. Model skill is dependent on event forcing strength and temporal proximity to the peak of the sea surface warming. A composite approach centered on maximum Niño-3.4 SSTs and lag relationships to energy fluxes and transports is used to identify mechanisms supporting tropical land warming. The composite necessarily moderates weather-scale variability of the individual events while retaining the systematic features across all events. We find that reduced continental upward motions lead to reduced cloudiness and more shortwave radiation at the surface, as well as reduced precipitation. The increased shortwave heating at the land surface, along with reduced soil moisture, leads to warmer surface temperature, more sensible heating, and warming of the lower troposphere. The composite provides a broad picture of the mechanisms governing the hydrologic response to El Niño forcing, but the regional and temporal responses can vary substantially for any given event. The 2015/16 El Niño, one of the strongest events, demonstrates some of the forced response noted in the composite, but with shifts in the evolution that depart from the composite, demonstrating the limitations of the composite and individuality of El Niño.
Brunner, Lukas; McSweeney, Carol; Ballinger, Andrew P.; Hegerl, Gabriele C.; Befort, Daniel J.; O’Reilly, Chris; Benassi, Marianna; Booth, Ben; Harris, Glen; Lowe, Jason; Coppola, Erika; Nogherotto, Rita; Knutti, Reto; Lenderink, Geert; de Vries, Hylke; Qasmi, Saïd; Ribes, Aurélien; Stocchi, Paolo; Undorf, SabineBrunner, L., C. McSweeney, A. P. Ballinger, G. C. Hegerl, D. J. Befort, C. O’Reilly, M. Benassi, B. Booth, G. Harris, J. Lowe, E. Coppola, R. Nogherotto, R. Knutti, G. Lenderink, H. de Vries, S. Qasmi, A. Ribes, P. Stocchi, S. Undorf, 2020: Comparing methods to constrain future European climate projections using a consistent framework. J. Climate, 33(20), 8671–8692. doi: 10.1175/JCLI-D-19-0953.1. Political decisions, adaptation planning, and impact assessments need reliable estimates of future climate change and related uncertainties. In order to provide these estimates, different approaches to constrain, filter, or weight climate model projections into probabilistic distributions have been proposed. However, an assessment of multiple such methods to, for example, expose cases of agreement or disagreement, is often hindered by a lack of coordination, with methods focusing on a variety of variables, time periods, regions, or model pools. Here, a consistent framework is developed to allow a quantitative comparison of eight different methods; focus is given to summer temperature and precipitation change in three spatial regimes in Europe in 2041-2060 relative to 1995-2014. The analysis draws on projections from several large ensembles, the CMIP5 multi-model ensemble, and perturbed physics ensembles, all using the high-emission scenario RCP8.5. The methods’ key features are summarized, assumptions are discussed and resulting constrained distributions are presented. Method agreement is found to be dependent on the investigated region but is generally higher for median changes than for the uncertainty ranges. This study, therefore, highlights the importance of providing clear context about how different methods affect the assessed uncertainty, particularly the upper and lower percentiles that are of interest to risk-averse stakeholders. The comparison also exposes cases where diverse lines of evidence lead to diverging constraints; additional work is needed to understand how the underlying differences between methods lead to such disagreements and to provide clear guidance to users.
Brutsaert, Wilfried; Cheng, Lei; Zhang, Lu; Brutsaert, Wilfried; Cheng, Lei; Zhang, LuBrutsaert, W., L. Cheng, L. Zhang, W. Brutsaert, L. Cheng, L. Zhang, 2020: Spatial Distribution of Global Landscape Evaporation in the Early Twenty-First Century by Means of a Generalized Complementary Approach. J. Hydrometeor., 21(2), 551–581. doi: 10.1175/JHM-D-19-0208.1. AbstractA generalized implementation of the complementary principle was applied to estimate global land surface evaporation and its spatial distribution. The single parameter in the method was cali...
Burgdorf, Martin J.; Müller, Thomas G.; Buehler, Stefan A.; Prange, Marc; Brath, ManfredBurgdorf, M. J., T. G. Müller, S. A. Buehler, M. Prange, M. Brath, 2020: Characterization of the High-Resolution Infrared Radiation Sounder Using Lunar Observations. Remote Sensing, 12(9), 1488. doi: 10.3390/rs12091488. The High-Resolution Infrared Radiation Sounder (HIRS) has been operational since 1975 on different satellites. In spite of this long utilization period, the available information about some of its basic properties is incomplete or contradictory. We have approached this problem by analyzing intrusions of the Moon in the deep space view of HIRS/2 through HIRS/4. With this method we found: (1) The diameters of the field of view of HIRS/2, HIRS/3, and HIRS/4 have the relative proportions of 1.4 ° to 1.3 ° to 0.7 ° with all channels; (2) the co-registration differs by up to 0.031 ° among the long-wave and by up to 0.015 ° among the shortwave spectral channels in the along-track direction; (3) the photometric calibration is consistent within 0.7% or less for channels 2–7 (1.2% for HIRS/2), similar values were found for channels 13–16; (4) the non-linearity of the short-wavelength channels is negligible; and (5) the contribution of reflected sunlight to the flux in the short-wavelength channels can be determined in good approximation, if the emissivity of the surface is known. calibration; surface; infrared sounder; moon
Butler, John C.Butler, J. C., 2020: CERES Gimbal Performance on Terra. Lubricants, 8(8), 79. doi: 10.3390/lubricants8080079. The Terra satellite has been operating in orbit for 20 years. The Terra satellite is also called the flagship earth-observing satellite. The two Clouds and the Earth’s Radiant Energy System CERES instruments on board continue to function nominally. Their expected mission lifetime was 7 years. Critical to their performance is the longevity of the scanning gimbals. This can be traced to the performance of the fluid-lubricated bearings. Two metrics are used to estimate their lifetime and health. Both lend themselves to readily available data and ease of interpretation. One is predicting the evaporative lubricant loss. This analysis indicates that the lubricant supply is adequate for the continual life of the gimbals. The second is trending the torque with time. Torque precursors are sampled quarterly. These data are converted to torque. Two types of torque behavior were examined. Contrasting torque data have supported the conclusion that the gimbals are operating nominally. This can be partially attributed to the design choices for the bearings and lubricant. The aim of this paper is to quantitatively describe the present health and expected life of the CERES gimbals on the Terra satellite. space vehicles; bearings; lubricant; torque
Cao, Yunfeng; Liang, Shunlin; Yu, MengCao, Y., S. Liang, M. Yu, 2020: Observed low-frequency linkage between Northern Hemisphere tropical expansion and polar vortex weakening from 1979 to 2012. Atmospheric Research, 243, 105034. doi: 10.1016/j.atmosres.2020.105034. In recent decades, the northern hemisphere (NH) atmospheric meridional circulation has experienced unprecedented changes. The NH tropical belt is significantly expanding toward high latitudes, and the Arctic polar vortex is continually weakening. Both phenomena have led to severe consequences on the Earth's surface, such as more frequent droughts in the subtropics and accelerated sea ice loss in the Arctic. However, the potential linkage between these phenomena and the underlying mechanisms have rarely been discussed. In this study, we report strong observational evidence that the NH tropical boundary and tropospheric polar vortex are synchronously changing, based on analysis of long-term satellite records from 1979 to 2012. Our investigation suggests that both the variance of the NH tropical boundary and tropospheric polar vortex from 1979 to 2012 are associated to the natural anomaly of NH mid-latitude sea surface temperature. The low-frequency sea surface temperature anomalies over the North Pacific (i.e., the Pacific Decadal Oscillation, PDO) and Atlantic (i.e., the Atlantic Multidecadal Oscillation, AMO) could explain 61% of the NH tropical boundary variance and 56% of the polar vortex variance from 1979 to 2012. Atlantic Multidecadal Oscillation; Low-frequency linkage; NH tropical expansion; Pacific Decadal Oscillation; Polar vortex weakening
Chen, Jiang; He, Tao; Jiang, Bo; Liang, ShunlinChen, J., T. He, B. Jiang, S. Liang, 2020: Estimation of all-sky all-wave daily net radiation at high latitudes from MODIS data. Remote Sensing of Environment, 245, 111842. doi: 10.1016/j.rse.2020.111842. Surface all-wave net radiation (Rn) plays an important role in various land surface processes, such as agricultural, ecological, hydrological, and biogeochemical processes. Recently, remote sensing of Rn at regional and global scales has attracted considerable attention and has achieved significant advances. However, there are many issues in estimating all-sky daily average Rn at high latitudes, such as posing greater uncertainty by surface and atmosphere satellite products at high latitudes, and unavailability of real-time and accurate cloud base height and temperature parameters. In this study, we developed the LRD (length ratio of daytime) classification model using the genetic algorithm-artificial neural network (GA-ANN) to estimate all-sky daily average Rn at high latitudes. With a very high temporal repeating frequency (~6 to 20 times per day) at high latitudes, data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to test the proposed method. Rn measurements at 82 sites and top-of-atmosphere (TOA) data of MODIS from 2000 to 2017 were matched for model training and validation. Two models for estimating daily average Rn were developed: model I based on instantaneous daytime MODIS observation and model II based on instantaneous nighttime MODIS observation. Validation results of model I showed an R2 of 0.85, an RMSE of 23.66 W/m2, and a bias of 0.27 W/m2, whereas these values were 0.51, 15.04 W/m2, and −0.08 W/m2 for model II, respectively. Overall, the proposed machine learning algorithm with the LRD classification can accurately estimate the all-sky daily average Rn at high latitudes. Mapping of Rn over the high latitudes at 1 km spatial resolution showed a similar spatial distribution to Rn estimates from the Clouds and the Earth's Radiant Energy System (CERES) product. This method has the potential for operational monitoring of spatio-temporal change of Rn at high latitudes with a long-term coverage of MODIS observations. MODIS; Net radiation; High latitudes; High spatial resolution; Length ratio of daytime
Chen, Liang; Dirmeyer, Paul A.Chen, L., P. A. Dirmeyer, 2020: Reconciling the disagreement between observed and simulated temperature responses to deforestation. Nature Communications, 11(1), 1-10. doi: 10.1038/s41467-019-14017-0. Models show a cooler surface temperature response to deforestation than observations which has been attributed to uncertainties in the models. A comparison of satellite observations and model experiments shows that the disagreement is due to the role of atmospheric feedbacks, which are not well captured in the observational space-for-time approach.
Cherian, Ribu; Quaas, JohannesCherian, R., J. Quaas, 2020: Trends in AOD, Clouds, and Cloud Radiative Effects in Satellite Data and CMIP5 and CMIP6 Model Simulations Over Aerosol Source Regions. Geophysical Research Letters, 47(9), e2020GL087132. doi: 10.1029/2020GL087132. Several regions worldwide have seen significant trends in anthropogenic aerosol emissions during the period of detailed satellite observations since 2001. Over Europe (EUR) and North America (NAM) there were strong declines, over China increases then declines and over India, strong increases. Regional trends in model-simulated aerosol optical depth (AOD) and cloud radiative effects in both the Fifth and Sixth Coupled Model Intercomparison Projects (CMIP5 and CMIP6) are broadly consistent with the ones from satellite retrievals in most parts of EUR, NAM and India. CMIP6 models better match satellite-derived AOD trend in western NAM (increasing) and eastern China (decreasing), where CMIP5 models failed, pointing to improved anthropogenic aerosol emissions. Drop concentration trends in both observations and models qualitatively match AOD trends. The result for solar cloud radiative effect in models, however, is due to compensating errors: Models fail to reproduce observed liquid water path trends and show, in turn, opposite trends in cloud fraction. climate models; cloud radiative effects; aerosol optical depth; aerosol emission trend; aerosol source regions; CDNC
Cheruy, Frédérique; Ducharne, Agnés; Hourdin, Frédéric; Musat, Ionela; Vignon, Etienne; Gastineau, Guillaume; Bastrikov, Vladislav; Vuichard, Nicolas; Diallo, Binta; Dufresne, Jean-Louis; Ghattas, Josefine; Grandpeix, Jean-Yves; Idelkadi, Abderrahmane; Mellul, Lidia; Maignan, Fabienne; Menegoz, Martin; Ottlé, Catherine; Peylin, Philippe; Servonnat, Jérôme; Wang, Fuxing; Zhao, YanfengCheruy, F., A. Ducharne, F. Hourdin, I. Musat, E. Vignon, G. Gastineau, V. Bastrikov, N. Vuichard, B. Diallo, J. Dufresne, J. Ghattas, J. Grandpeix, A. Idelkadi, L. Mellul, F. Maignan, M. Menegoz, C. Ottlé, P. Peylin, J. Servonnat, F. Wang, Y. Zhao, 2020: Improved near surface continental climate in IPSL-CM6A-LR by combined evolutions of atmospheric and land surface physics. Journal of Advances in Modeling Earth Systems, 12(10), e2019MS002005. doi: 10.1029/2019MS002005. keypoints The representation of the land-atmosphere coupled system by the IPSL model is thoroughly evaluated. Improvements with respect to previous versions are documented in the context of the Coupled Model Intercomparison Project, CMIP. Advanced parameterization of land surface and atmospheric processes, tuning of the radiation and the turbulent mixing yielded many improvements. hydrology; climate modelling; atmosphere-land surface interactions; soil moisture; stable boundary layer; temperature bias
Cho, Heeje; Jun, Sang-Yoon; Ho, Chang-Hoi; McFarquhar, GregCho, H., S. Jun, C. Ho, G. McFarquhar, 2020: Simulations of Winter Arctic Clouds and Associated Radiation Fluxes Using Different Cloud Microphysics Schemes in the Polar WRF: Comparisons With CloudSat, CALIPSO, and CERES. Journal of Geophysical Research: Atmospheres, 125(2), e2019JD031413. doi: 10.1029/2019JD031413. Key Points Winter Arctic clouds simulated by the polar version of the Weather Research and Forecasting model are compared with satellite retrievals The cloud amount and cloud top height of model simulations agree well with those of satellite retrievals The downward longwave radiation at the surface shows realistic temporal variations, but is sensitive to the cloud microphysics scheme choice cloud microphysics; Polar WRF; satellite observation; surface radiation; winter Arctic cloud
Choi, Yong-Sang; Hwang, Jiwon; Ok, Jung; Park, Doo-Sun R.; Su, Hui; Jiang, Jonathan H.; Huang, Lei; Limpasuvan, TyChoi, Y., J. Hwang, J. Ok, D. R. Park, H. Su, J. H. Jiang, L. Huang, T. Limpasuvan, 2020: Effect of Arctic clouds on the ice-albedo feedback in midsummer. International Journal of Climatology, 40(10), 4707-4714. doi: 10.1002/joc.6469. The Arctic clouds should be an important factor that affects the summertime sea ice. By reflecting the incoming solar radiation before it reaches the surface, the Arctic clouds may prevent the surface from absorbing tremendous solar radiation due to the reduced sea ice. This cloud effect will lead to intervene the feedback relation between the solar radiation and the sea ice change. However, few studies have quantitatively investigated the Arctic cloud effect on the ice-albedo feedback. This study found that the Arctic clouds regulate the melting speed of sea ice in midsummer months (June to August) based on the data from multiple sources, that is, satellite, reanalysis, and climate models. During this period, the fraction of Arctic clouds with the net radiative cooling effect is almost invariable with sea ice reduction. However, despite of the steady cloud fraction in the midsummer months, the shortwave cloud radiative effect (total-sky minus clear-sky absorbed shortwave radiation) was found to significantly increase with the reduced sea ice concentration (0.64 W m−2%−1 in CERES, 0.73 W m−2%−1 in ERA5). This is because the clouds present more contrast of albedo with the sea ice-free ocean than the sea ice-covered ocean. Finally, our analyses show that the Arctic clouds are nearly halving the strength of the ice-albedo feedback in the midsummer months. These results imply that the sea ice reduction could have been much faster in the past decades in the absence of the cloud effect found here. Arctic clouds; Arctic Sea ice; cloud effect; ice-albedo feedback; midsummer
Christensen, Matthew W.; Jones, William K.; Stier, PhilipChristensen, M. W., W. K. Jones, P. Stier, 2020: Aerosols enhance cloud lifetime and brightness along the stratus-to-cumulus transition. Proceedings of the National Academy of Sciences, 117(30), 17591-17598. doi: 10.1073/pnas.1921231117. Anthropogenic aerosols are hypothesized to enhance planetary albedo and offset some of the warming due to the buildup of greenhouse gases in Earth’s atmosphere. Aerosols can enhance the coverage, reflectance, and lifetime of warm low-level clouds. However, the relationship between cloud lifetime and aerosol concentration has been challenging to measure from polar orbiting satellites. We estimate two timescales relating to the formation and persistence of low-level clouds over 1○×1○1○×1○1○×1○ spatial domains using multiple years of geostationary satellite observations provided by the Clouds and Earth’s Radiant Energy System (CERES) Synoptic (SYN) product. Lagrangian trajectories spanning several days along the classic stratus-to-cumulus transition zone are stratified by aerosol optical depth and meteorology. Clouds forming in relatively polluted trajectories tend to have lighter precipitation rates, longer average lifetime, and higher cloud albedo and cloud fraction compared with unpolluted trajectories. While liquid water path differences are found to be negligible, we find direct evidence of increased planetary albedo primarily through increased drop concentration (NdNdNd) and cloud fraction, with the caveat that the aerosol influence on cloud fraction is positive only for stable atmospheric conditions. While the increase in cloud fraction can be large typically in the beginning of trajectories, the Twomey effect accounts for the bulk (roughly 3/4) of the total aerosol indirect radiative forcing estimate. clouds; aerosols; radiative forcing
| 2022-10-07T07:15:51 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5060728192329407, "perplexity": 8104.652436721979}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337971.74/warc/CC-MAIN-20221007045521-20221007075521-00727.warc.gz"}
|
https://zbmath.org/authors/?q=au%3AStefan+M%C3%BCller+cc%3A49
|
# zbMATH — the first resource for mathematics
## Müller, Stefan
Compute Distance To:
Author ID: muller.stefan.1 Published as: Müller, S.; Müller, Stefan Homepage: http://www.hcm.uni-bonn.de/people/profile/stefan-mueller/ External Links: MGP · Wikidata · dblp · GND Awards: EMS Prize (1992)
Documents Indexed: 141 Publications since 1987
all top 5
#### Co-Authors
20 single-authored 16 Conti, Sergio 11 Dolzmann, Georg 10 DeSimone, Antonio 10 Šverák, Vladimír 9 Mora, Maria Giovanna 8 James, Richard D. 8 Kohn, Robert Vita 7 Otto, Felix 6 Fonseca, Irene 6 Garroni, Adriana 5 Friesecke, Gero 5 Kirchheim, Bernd 5 Struwe, Michael 4 Ortiz, Michael 4 Spector, Scott J. 3 Abels, Helmut 3 Chaudhuri, Nirmalendu 3 De Lellis, Camillo 3 Flucher, Martin 3 Hungerbuhler, Norbert 3 Kienzler, Reinhold 3 McDowell, David L. 3 Palombaro, Mariapia 3 Werner, Ewald A. 2 Ball, John M. 2 Ben Belgacem, Hafedh 2 Freire, Alexandre 2 Geymonat, Giuseppe 2 Kopecká, Eva 2 Lewicka, Marta 2 Maggi, Francesco 2 Müller, Paul F. X. 2 Olbermann, Heiner 2 Pakzad, Mohammad Reza 2 Schweiger, Florian 2 Tang, Qi 2 Triantafyllidis, Nicolas 2 Yan, Baisheng 1 Adams, Stefan 1 Alberti, Giovanni 1 Bourne, David P. 1 Carstensen, Carsten 1 Cotar, Codina 1 Deuschel, Jean-Dominique 1 Dmitrieva, Olga 1 Dondl, Patrick Werner 1 Esteban, Maria J. 1 Evans, Lawrence Craig 1 Faraco, Daniel 1 Francfort, Gilles A. 1 Giuliani, Alessandro 1 Koop, Andreas 1 Kotecký, Roman 1 Kröner, Dietmar 1 Lecumberry, Myriam 1 Lee, Jihoon 1 Leoni, Giovanni 1 Lienstromberg, Christina 1 Mielke, Alexander 1 Neukamm, Stefan 1 Pedregal, Pablo 1 Raabe, Dierk 1 Rieger, Marc Oliver 1 Röger, Matthias 1 Romeo, Mario 1 Scardia, Lucia 1 Schäfer, Rudolf 1 Schlömerkemper, Anja 1 Schmitz, Sven 1 Schroeter, Brian M. 1 Schultz, M. G. 1 Schupp, Bernhard 1 Sivaloganathan, Jeyabal 1 Süli, Endre E. 1 Sychev, Mikhail A. 1 Zeppieri, Caterina Ida
all top 5
#### Serials
15 Archive for Rational Mechanics and Analysis 14 Calculus of Variations and Partial Differential Equations 11 SIAM Journal on Mathematical Analysis 8 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 6 Comptes Rendus. Mathématique. Académie des Sciences, Paris 5 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 5 Oberwolfach Reports 4 Communications on Pure and Applied Mathematics 4 Comptes Rendus de l’Académie des Sciences. Série I 3 Indiana University Mathematics Journal 3 Journal of Differential Geometry 3 Journal of Functional Analysis 3 Journal für die Reine und Angewandte Mathematik 3 Communications in Partial Differential Equations 3 Journal of Nonlinear Science 2 Communications in Mathematical Physics 2 Mathematische Zeitschrift 2 Topological Methods in Nonlinear Analysis 2 Journal of the European Mathematical Society (JEMS) 1 Computer Methods in Applied Mechanics and Engineering 1 Journal of Mathematical Analysis and Applications 1 Mitteilungen der Deutschen Mathematiker-Vereinigung (DMV) 1 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 1 Inventiones Mathematicae 1 Journal of Differential Equations 1 Manuscripta Mathematica 1 Mathematische Annalen 1 Meccanica 1 Numerische Mathematik 1 Rendiconti del Seminario Matemàtico e Fisico di Milano 1 SIAM Journal on Numerical Analysis 1 Transactions of the American Mathematical Society 1 Revista Matemática Iberoamericana 1 Journal of the American Mathematical Society 1 IMRN. International Mathematics Research Notices 1 The Journal of Geometric Analysis 1 Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences 1 Bulletin of the American Mathematical Society. New Series 1 Continuum Mechanics and Thermodynamics 1 Tatra Mountains Mathematical Publications 1 NoDEA. Nonlinear Differential Equations and Applications 1 Documenta Mathematica 1 Vietnam Journal of Mathematics 1 ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik 1 Proceedings of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 1 Annals of Mathematics. Second Series 1 Multiscale Modeling & Simulation 1 GAMM-Mitteilungen 1 Bollettino dell’Unione Matematica Italiana
all top 5
#### Fields
75 Mechanics of deformable solids (74-XX) 55 Partial differential equations (35-XX) 52 Calculus of variations and optimal control; optimization (49-XX) 16 Statistical mechanics, structure of matter (82-XX) 11 Functional analysis (46-XX) 8 Real functions (26-XX) 7 Global analysis, analysis on manifolds (58-XX) 6 General and overarching topics; collections (00-XX) 6 Differential geometry (53-XX) 5 Harmonic analysis on Euclidean spaces (42-XX) 4 Ordinary differential equations (34-XX) 4 Numerical analysis (65-XX) 4 Fluid mechanics (76-XX) 3 Convex and discrete geometry (52-XX) 2 Potential theory (31-XX) 2 Operator theory (47-XX) 2 Probability theory and stochastic processes (60-XX) 2 Optics, electromagnetic theory (78-XX) 1 Measure and integration (28-XX) 1 Functions of a complex variable (30-XX) 1 Dynamical systems and ergodic theory (37-XX) 1 Difference and functional equations (39-XX) 1 Geometry (51-XX)
#### Citations contained in zbMATH Open
128 Publications have been cited 3,458 times in 2,003 Documents Cited by Year
A theorem on geometric rigidity and the derivation of nonlinear plate theory from three-dimensional elasticity. Zbl 1021.74024
Friesecke, Gero; James, Richard D.; Müller, Stefan
2002
A hierarchy of plate models derived from nonlinear elasticity by gamma-convergence. Zbl 1100.74039
Friesecke, Gero; James, Richard D.; Müller, Stefan
2006
Homogenization of nonconvex integral functionals and cellular elastic materials. Zbl 0629.73009
Müller, Stefan
1987
Variational models for microstructure and phase transitions. Zbl 0968.74050
Müller, Stefan
1999
$$\mathcal A$$-quasiconvexity, lower semicontinuity, and Young measures. Zbl 0940.49014
Fonseca, Irene; Müller, Stefan
1999
Homogenization of nonlinearly elastic materials, microscopic bifurcation and macroscopic loss of rank-one convexity. Zbl 0801.73008
Geymonat, Giuseppe; Müller, Stefan; Triantafyllidis, Nicolas
1993
Convex integration for Lipschitz mappings and counterexamples to regularity. Zbl 1083.35032
Müller, S.; Šverák, V.
2003
An existence theory for nonlinear elasticity that allows for cavitation. Zbl 0836.73025
Müller, Stefan; Spector, Scott J.
1995
Surface energy and microstructure in coherent phase transitions. Zbl 0803.49007
Kohn, Robert V.; Müller, Stefan
1994
Higher integrability of determinants and weak convergence in $$L^ 1$$. Zbl 0713.49004
Müller, Stefan
1990
Derivation of nonlinear bending theory for shells from three-dimensional nonlinear elasticity by Gamma-convergence. Zbl 1140.74481
Friesecke, Gero; James, Richard D.; Mora, Maria Giovanna; Müller, Stefan
2003
Analysis of concentration and oscillation effects generated by gradients. Zbl 0920.49009
Fonseca, Irene; Müller, Stefan; Pedregal, Pablo
1998
A uniqueness proof for the Wulff theorem. Zbl 0752.49019
Fonseca, Irene; Müller, Stefan
1991
Quasi-convex integrands and lower semicontinuity in $$L^ 1$$. Zbl 0764.49012
Fonseca, Irene; Müller, Stefan
1992
Singular perturbations as a selection criterion for periodic minimizing sequences. Zbl 0821.49015
Müller, Stefan
1993
Relaxation of quasiconvex functionals in $$BV(\Omega, \mathbb{R}^ N)$$ for integrands $$f(x, u, \bigtriangledown u)$$. Zbl 0788.49039
Fonseca, Irene; Müller, Stefan
1993
A reduced theory for thin-film micromagnetics. Zbl 1027.82042
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2002
On a new class of elastic deformations not allowing for cavitation. Zbl 0863.49002
Müller, S.; Qi, Tang; Yan, B. S.
1994
$$\Gamma$$-limit of a phase-field model of dislocations. Zbl 1094.82008
Garroni, A.; Müller, S.
2005
Convex integration with constraints and applications to phase transitions and partial differential equations. Zbl 0953.35042
Müller, S.; Šverák, V.
1999
Uniqueness and maximal regularity for nonlinear elliptic systems of $$n$$-Laplace type with measure valued right hand side. Zbl 0937.35065
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
2000
A variational model for dislocations in the line tension limit. Zbl 1158.74365
2006
Derivation of the nonlinear bending-torsion theory for inextensible rods by $$\Gamma$$-convergence. Zbl 1053.74027
Mora, Maria Giovanna; Müller, Stefan
2003
A compactness result in the gradient theory of phase transitions. Zbl 0986.49009
DeSimone, Antonio; Müller, Stefan; Kohn, Robert V.; Otto, Felix
2001
Attainment results for the two-well problem by convex integration. Zbl 0930.35038
1996
Microstructures with finite surface energy: The two-well problem. Zbl 0846.73054
Dolzmann, Georg; Müller, Stefan
1995
Det$$=\det$$. A remark on the distributional determinant. Zbl 0717.46033
Müller, Stefan
1990
Recent analytical developments in micromagnetics. Zbl 1151.35426
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2006
Studying nonlinear PDE by geometry in matrix space. Zbl 1290.35097
Kirchheim, Bernd; Müller, Stefan; Šverák, Vladimír
2003
A new approach to variational problems with multiple scales. Zbl 1021.49012
Alberti, Giovanni; Müller, Stefan
2001
Estimates for Green’s matrices of elliptic systems by $$L^ p$$ theory. Zbl 0846.35040
Dolzmann, G.; Müller, S.
1995
On surfaces of finite total curvature. Zbl 0853.53003
Müller, S.; Šverák, V.
1995
Optimal rigidity estimates for nearly umbilical surfaces. Zbl 1087.53004
de Lellis, Camillo; Müller, Stefan
2005
Lower semicontinuity and existence of minimizers in incremental finite-strain elastoplasticity. Zbl 1102.74006
Mielke, Alexander; Müller, Stefan
2006
Energy scaling of compressed elastic films – three-dimensional elasticity and reduced theories. Zbl 1041.74048
Ben Belgacem, Hafedh; Conti, Sergio; DeSimone, Antonio; Müller, Stefan
2002
Optimal existence theorems for nonhomogeneous differential inclusions. Zbl 0989.49012
Müller, S.; Sychev, M. A.
2001
Rigorous derivation of nonlinear plate theory and geometric rigidity. Zbl 1012.74043
Friesecke, Gero; Müller, Stefan; James, Richard D.
2002
Nonlinear elliptic systems with measure-valued right hand side. Zbl 0895.35029
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
1997
Hardy spaces and the two-dimensional Euler equations with nonnegative vorticity. Zbl 0802.35120
Evans, L. C.; Müller, S.
1994
Rigourous bounds for the Föppl-von Kármán theory of isotropically compressed plates. Zbl 1015.74029
Ben Belgacem, H.; Conti, S.; DeSimone, A.; Müller, S.
2000
Rank-one convexity implies quasiconvexity on diagonal matrices. Zbl 1055.49506
Müller, Stefan
1999
Local stress regularity in scalar nonconvex variational problems. Zbl 1012.49027
Carstensen, Carsten; Müller, Stefan
2002
Magnetic microstructures – a paradigm of multiscale problems. Zbl 0991.82038
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2000
Invertibility and a topological property of Sobolev maps. Zbl 0855.73028
Müller, Stefan; Spector, Scott J.; Tang, Qi
1996
Weak continuity of determinants and nonlinear elasticity. (Continuité faible des déterminants et applications à l’élasticité non linéaire). Zbl 0679.34051
Müller, Stefan
1988
A surprising higher integrability property of mappings with positive determinant. Zbl 0689.49006
Müller, Stefan
1989
The Föppl-von Kármán plate theory as a low energy $$\Gamma$$-limit of nonlinear elasticity. Zbl 1041.74043
Friesecke, Gero; James, Richard D.; Müller, Stefan
2002
A nonlinear model for inextensible rods as a low energy $$\varGamma$$-limit of three-dimensional nonlinear elasticity. Zbl 1109.74028
Mora, Maria Giovanna; Müller, Stefan
2004
The $$p$$-harmonic system with measure-valued right hand side. Zbl 0879.35052
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
1997
The uniform Korn-Poincaré inequality in thin domains. Zbl 1253.74055
Lewicka, Marta; Müller, Stefan
2011
Hardy space methods for nonlinear partial differential equations. Zbl 0811.35025
Müller, Stefan
1994
Regularity properties of isometric immersions. Zbl 1082.58010
2005
Internal variables and fine-scale oscillations in micromagnetics. Zbl 0814.73054
James, R. D.; Müller, Stefan
1994
Data-driven problems in elasticity. Zbl 1402.35276
Conti, S.; Müller, S.; Ortiz, M.
2018
Sufficient conditions for the validity of the Cauchy-Born rule close to $$\mathrm{SO}(n)$$. Zbl 1146.74006
Conti, Sergio; Dolzmann, Georg; Kirchheim, Bernd; Müller, Stefan
2006
A $$C^{0}$$ estimate for nearly umbilical surfaces. Zbl 1100.53005
De Lellis, Camillo; Müller, Stefan
2006
On the $$\Gamma$$-convergence of discrete dynamics and variational integrators. Zbl 1136.37350
Müller, S.; Ortiz, M.
2004
Singular kernels, multiscale decomposition of microstructure, and dislocation models. Zbl 1251.74006
Conti, Sergio; Garroni, Adriana; Müller, Stefan
2011
Stability of slender bodies under compression and validity of the von Kármán theory. Zbl 1200.74060
Lecumberry, Myriam; Müller, Stefan
2009
On the singular support of the distributional determinant. Zbl 0792.46027
Müller, Stefan
1993
On quasiconvex functions which are homogeneous of degree 1. Zbl 0736.26006
Müller, Stefan
1992
Convergence of equilibria of three-dimensional thin elastic beams. Zbl 1142.74022
Mora, M. G.; Müller, S.
2008
Two-dimensional modelling of soft ferromagnetic films. Zbl 1065.74028
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix; Schäfer, Rudolf
2001
The time-dependent von Kármán plate equation as a limit of 3d nonlinear elasticity. Zbl 1346.74110
Abels, Helmut; Mora, Maria Giovanna; Müller, Stefan
2011
The div-curl lemma for sequences whose divergence and curl are compact in $$W^{-1,1}$$. Zbl 1235.46034
Conti, Sergio; Dolzmann, Georg; Müller, Stefan
2011
Convergence of equilibria of thin elastic plates – the von Kármán case. Zbl 1141.74034
2008
Rigidity estimate for two incompatible wells. Zbl 1086.49010
Chaudhuri, Nirmalendu; Müller, Stefan
2004
A sharp version of Zhang’s theorem on truncating sequences of gradients. Zbl 0942.49013
Müller, Stefan
1999
Unexpected solutions of first and second order partial differential equations. Zbl 0896.35029
1998
Korn’s second inequality and geometric rigidity with mixed growth conditions. Zbl 1295.35369
Conti, Sergio; Dolzmann, Georg; Müller, Stefan
2014
Conical singularities in thin elastic sheets. Zbl 1285.49031
Müller, Stefan; Olbermann, Heiner
2014
Sobolev maps with integer degree and applications to Skyrme’s problem. Zbl 0757.49010
Esteban, Maria J.; Müller, Stefan
1992
Strict convexity of the free energy for a class of non-convex gradient models. Zbl 1173.82010
Cotar, Codina; Deuschel, Jean-Dominique; Müller, Stefan
2009
$$\mathcal A$$-quasiconvexity: weak-star convergence and the gap. Zbl 1064.49016
Fonseca, Irene; Leoni, Giovanni; Müller, Stefan
2004
Parabolic systems with nowhere smooth solutions. Zbl 1116.35059
Müller, Stefan; Rieger, Marc Oliver; Šverák, Vladimír
2005
Weak compactness of wave maps and harmonic maps. Zbl 0924.58011
Freire, Alexandre; Müller, Stefan; Struwe, Michael
1998
Weak convergence of wave maps from $$(1+2)$$-dimensional Minkowski space to Riemannian manifolds. Zbl 0906.35061
Freire, Alexandre; Müller, Stefan; Struwe, Michael
1997
Global existence of wave maps in 1+2 dimensions with finite energy data. Zbl 0896.35086
Müller, Stefan; Struwe, Michael
1996
Convergence of equilibria of planar thin elastic beams. Zbl 1125.74026
Mora, M. G.; Müller, S.; Schultz, M. G.
2007
Rigorous derivation of Föppl’s theory for clamped elastic membranes leads to relaxation. Zbl 1146.74025
Conti, Sergio; Maggi, Francesco; Müller, Stefan
2007
Rank-one convex functions on $$2\times 2$$ symmetric matrices and laminates on rank-three lines. Zbl 1135.26301
Conti, S.; Faraco, D.; Maggi, F.; Müller, S.
2005
Repulsive interaction of Néel walls, and the internal length scale of the cross-tie wall. Zbl 1059.82046
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2003
Radial symmetry and decay rate of variational ground states in the zero mass case. Zbl 0908.35005
Flucher, M.; Müller, S.
1998
Concentration of low energy extremals: Identification of concentration points. Zbl 1004.35040
Flucher, M.; Garroni, A.; Müller, S.
2002
Compensated compactness, separately convex functions and interpolatory estimates between Riesz transforms and Haar projections. Zbl 1230.49009
Lee, Jihoon; Müller, Paul F. X.; Müller, Stefan
2011
Combined effects of homogenization and singular perturbations in elasticity. Zbl 0802.35007
Francfort, G. A.; Müller, S.
1994
Large time existence for thin vibrating plates. Zbl 1247.74019
Abels, Helmut; Mora, Maria Giovanna; Müller, Stefan
2011
The two-well problem in three dimensions. Zbl 0956.74039
Dolzmann, Georg; Kirchheim, Bernd; Müller, Stefan; Šverák, Vladimir
2000
Sharp stability results for almost conformal maps in even dimensions. Zbl 0966.35016
Müller, Stefan; Šverák, Vladimir; Yan, Baisheng
1999
An isoperimetric estimate and $$W^{1,p}$$-quasiconvexity in nonlinear elasticity. Zbl 0929.74013
Müller, Stefan; Sivaloganathan, Jeyabal; Spector, Scott J.
1999
Energy bounds for a compressed elastic film on a substrate. Zbl 1387.74069
Bourne, David P.; Conti, Sergio; Müller, Stefan
2017
Mathematical problems in thin elastic sheets: scaling limits, packing, crumpling and singularities. Zbl 1372.35003
Müller, Stefan
2017
On the optimal constants in Korn’s and geometric rigidity estimates in bounded and unbounded domains, under Neumann boundary conditions. Zbl 1405.74010
Lewicka, Marta; Müller, Stefan
2016
On a differential inclusion related to the Born-Infeld equations. Zbl 1301.35226
Müller, Stefan; Palombaro, Mariapia
2014
Confined structures of least bending energy. Zbl 1296.53127
Müller, Stefan; Röger, Matthias
2014
Derivation of a rod theory for biphase materials with dislocations at the interface. Zbl 1274.74064
Müller, Stefan; Palombaro, Mariapia
2013
Finite range decomposition for families of gradient Gaussian measures. Zbl 1263.60047
Adams, Stefan; Kotecký, Roman; Müller, Stefan
2013
Striped periodic minimizers of a two-dimensional model for martensitic phase transitions. Zbl 1448.74082
Giuliani, Alessandro; Müller, Stefan
2012
On the commutability of homogenization and linearization in finite elasticity. Zbl 1262.74029
Müller, Stefan; Neukamm, Stefan
2011
Existence of minimizers for a polyconvex energy in a crystal with dislocations. Zbl 1134.74015
Müller, Stefan; Palombaro, Mariapia
2008
Data-driven finite elasticity. Zbl 1437.35654
Conti, S.; Müller, S.; Ortiz, M.
2020
Optimal-order finite difference approximation of generalized solutions to the biharmonic equation in a cube. Zbl 07154067
Müller, Stefan; Schweiger, Florian; Süli, Endre
2020
Estimates for the Green’s function of the discrete Bilaplacian in dimensions 2 and 3. Zbl 1422.65324
Müller, Stefan; Schweiger, Florian
2019
Data-driven problems in elasticity. Zbl 1402.35276
Conti, S.; Müller, S.; Ortiz, M.
2018
Energy bounds for a compressed elastic film on a substrate. Zbl 1387.74069
Bourne, David P.; Conti, Sergio; Müller, Stefan
2017
Mathematical problems in thin elastic sheets: scaling limits, packing, crumpling and singularities. Zbl 1372.35003
Müller, Stefan
2017
Homogenization of vector-valued partition problems and dislocation cell structures in the plane. Zbl 06722635
Conti, Sergio; Garroni, Adriana; Müller, Stefan
2017
On the optimal constants in Korn’s and geometric rigidity estimates in bounded and unbounded domains, under Neumann boundary conditions. Zbl 1405.74010
Lewicka, Marta; Müller, Stefan
2016
Gradient theory for geometrically nonlinear plasticity via the homogenization of dislocations. Zbl 1456.74018
Müller, Stefan; Scardia, Lucia; Zeppieri, Caterina Ida
2015
Microstructure in plasticity, a comparison between theory and experiment. Zbl 1370.74026
Dmitrieva, Olga; Raabe, Dierk; Müller, Stefan; Dondl, Patrick W.
2015
Korn’s second inequality and geometric rigidity with mixed growth conditions. Zbl 1295.35369
Conti, Sergio; Dolzmann, Georg; Müller, Stefan
2014
Conical singularities in thin elastic sheets. Zbl 1285.49031
Müller, Stefan; Olbermann, Heiner
2014
On a differential inclusion related to the Born-Infeld equations. Zbl 1301.35226
Müller, Stefan; Palombaro, Mariapia
2014
Confined structures of least bending energy. Zbl 1296.53127
Müller, Stefan; Röger, Matthias
2014
Almost conical deformations of thin sheets with rotational symmetry. Zbl 1290.49087
Müller, Stefan; Olbermann, Heiner
2014
Derivation of a rod theory for biphase materials with dislocations at the interface. Zbl 1274.74064
Müller, Stefan; Palombaro, Mariapia
2013
Finite range decomposition for families of gradient Gaussian measures. Zbl 1263.60047
Adams, Stefan; Kotecký, Roman; Müller, Stefan
2013
Striped periodic minimizers of a two-dimensional model for martensitic phase transitions. Zbl 1448.74082
Giuliani, Alessandro; Müller, Stefan
2012
The uniform Korn-Poincaré inequality in thin domains. Zbl 1253.74055
Lewicka, Marta; Müller, Stefan
2011
Singular kernels, multiscale decomposition of microstructure, and dislocation models. Zbl 1251.74006
Conti, Sergio; Garroni, Adriana; Müller, Stefan
2011
The time-dependent von Kármán plate equation as a limit of 3d nonlinear elasticity. Zbl 1346.74110
Abels, Helmut; Mora, Maria Giovanna; Müller, Stefan
2011
The div-curl lemma for sequences whose divergence and curl are compact in $$W^{-1,1}$$. Zbl 1235.46034
Conti, Sergio; Dolzmann, Georg; Müller, Stefan
2011
Compensated compactness, separately convex functions and interpolatory estimates between Riesz transforms and Haar projections. Zbl 1230.49009
Lee, Jihoon; Müller, Paul F. X.; Müller, Stefan
2011
Large time existence for thin vibrating plates. Zbl 1247.74019
Abels, Helmut; Mora, Maria Giovanna; Müller, Stefan
2011
On the commutability of homogenization and linearization in finite elasticity. Zbl 1262.74029
Müller, Stefan; Neukamm, Stefan
2011
Monotone curves. Zbl 1238.46017
Kirchheim, Bernd; Kopecká, Eva; Müller, Stefan
2011
Stability of slender bodies under compression and validity of the von Kármán theory. Zbl 1200.74060
Lecumberry, Myriam; Müller, Stefan
2009
Strict convexity of the free energy for a class of non-convex gradient models. Zbl 1173.82010
Cotar, Codina; Deuschel, Jean-Dominique; Müller, Stefan
2009
Do projections stay close together? Zbl 1160.51016
Kirchheim, Bernd; Kopecká, Eva; Müller, Stefan
2009
Convergence of equilibria of three-dimensional thin elastic beams. Zbl 1142.74022
Mora, M. G.; Müller, S.
2008
Convergence of equilibria of thin elastic plates – the von Kármán case. Zbl 1141.74034
2008
Existence of minimizers for a polyconvex energy in a crystal with dislocations. Zbl 1134.74015
Müller, Stefan; Palombaro, Mariapia
2008
Convergence of equilibria of planar thin elastic beams. Zbl 1125.74026
Mora, M. G.; Müller, S.; Schultz, M. G.
2007
Rigorous derivation of Föppl’s theory for clamped elastic membranes leads to relaxation. Zbl 1146.74025
Conti, Sergio; Maggi, Francesco; Müller, Stefan
2007
Derivation of a rod theory for multiphase materials. Zbl 1105.74016
Mora, Maria Giovanna; Müller, Stefan
2007
Scaling of the energy for thin martensitic films. Zbl 1108.74039
Chaudhuri, Nirmalendu; Müller, Stefan
2007
A hierarchy of plate models derived from nonlinear elasticity by gamma-convergence. Zbl 1100.74039
Friesecke, Gero; James, Richard D.; Müller, Stefan
2006
A variational model for dislocations in the line tension limit. Zbl 1158.74365
2006
Recent analytical developments in micromagnetics. Zbl 1151.35426
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2006
Lower semicontinuity and existence of minimizers in incremental finite-strain elastoplasticity. Zbl 1102.74006
Mielke, Alexander; Müller, Stefan
2006
Sufficient conditions for the validity of the Cauchy-Born rule close to $$\mathrm{SO}(n)$$. Zbl 1146.74006
Conti, Sergio; Dolzmann, Georg; Kirchheim, Bernd; Müller, Stefan
2006
A $$C^{0}$$ estimate for nearly umbilical surfaces. Zbl 1100.53005
De Lellis, Camillo; Müller, Stefan
2006
$$\Gamma$$-limit of a phase-field model of dislocations. Zbl 1094.82008
Garroni, A.; Müller, S.
2005
Optimal rigidity estimates for nearly umbilical surfaces. Zbl 1087.53004
de Lellis, Camillo; Müller, Stefan
2005
Regularity properties of isometric immersions. Zbl 1082.58010
2005
Parabolic systems with nowhere smooth solutions. Zbl 1116.35059
Müller, Stefan; Rieger, Marc Oliver; Šverák, Vladimír
2005
Rank-one convex functions on $$2\times 2$$ symmetric matrices and laminates on rank-three lines. Zbl 1135.26301
Conti, S.; Faraco, D.; Maggi, F.; Müller, S.
2005
Self-similar folding patterns and energy scaling in compressed elastic sheets. Zbl 1082.74030
Conti, Sergio; DeSimone, Antonio; Müller, Stefan
2005
A nonlinear model for inextensible rods as a low energy $$\varGamma$$-limit of three-dimensional nonlinear elasticity. Zbl 1109.74028
Mora, Maria Giovanna; Müller, Stefan
2004
On the $$\Gamma$$-convergence of discrete dynamics and variational integrators. Zbl 1136.37350
Müller, S.; Ortiz, M.
2004
Rigidity estimate for two incompatible wells. Zbl 1086.49010
Chaudhuri, Nirmalendu; Müller, Stefan
2004
$$\mathcal A$$-quasiconvexity: weak-star convergence and the gap. Zbl 1064.49016
Fonseca, Irene; Leoni, Giovanni; Müller, Stefan
2004
Convex integration for Lipschitz mappings and counterexamples to regularity. Zbl 1083.35032
Müller, S.; Šverák, V.
2003
Derivation of nonlinear bending theory for shells from three-dimensional nonlinear elasticity by Gamma-convergence. Zbl 1140.74481
Friesecke, Gero; James, Richard D.; Mora, Maria Giovanna; Müller, Stefan
2003
Derivation of the nonlinear bending-torsion theory for inextensible rods by $$\Gamma$$-convergence. Zbl 1053.74027
Mora, Maria Giovanna; Müller, Stefan
2003
Studying nonlinear PDE by geometry in matrix space. Zbl 1290.35097
Kirchheim, Bernd; Müller, Stefan; Šverák, Vladimír
2003
Repulsive interaction of Néel walls, and the internal length scale of the cross-tie wall. Zbl 1059.82046
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2003
Rank-one convexity implies quasi-convexity on certain hypersurfaces. Zbl 1054.49018
Chaudhuri, Nirmalendu; Müller, Stefan
2003
Multiscale modeling of materials – the role of analysis. Zbl 1065.74056
Conti, Sergio; DeSimone, Antonio; Dolzmann, Georg; Müller, Stefan; Otto, Felix
2003
Polyconvexity equals rank-one convexity for connected isotropic sets in $$\mathbb M^{2\times 2}$$. Zbl 1050.49010
Conti, Sergio; De Lellis, Camillo; Müller, Stefan; Romeo, Mario
2003
Concentration phenomena for the volume functional in unbounded domains: identification of concentration points. Zbl 1161.49305
Garroni, A.; Müller, S.
2003
A theorem on geometric rigidity and the derivation of nonlinear plate theory from three-dimensional elasticity. Zbl 1021.74024
Friesecke, Gero; James, Richard D.; Müller, Stefan
2002
A reduced theory for thin-film micromagnetics. Zbl 1027.82042
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2002
Energy scaling of compressed elastic films – three-dimensional elasticity and reduced theories. Zbl 1041.74048
Ben Belgacem, Hafedh; Conti, Sergio; DeSimone, Antonio; Müller, Stefan
2002
Rigorous derivation of nonlinear plate theory and geometric rigidity. Zbl 1012.74043
Friesecke, Gero; Müller, Stefan; James, Richard D.
2002
Local stress regularity in scalar nonconvex variational problems. Zbl 1012.49027
Carstensen, Carsten; Müller, Stefan
2002
The Föppl-von Kármán plate theory as a low energy $$\Gamma$$-limit of nonlinear elasticity. Zbl 1041.74043
Friesecke, Gero; James, Richard D.; Müller, Stefan
2002
Concentration of low energy extremals: Identification of concentration points. Zbl 1004.35040
Flucher, M.; Garroni, A.; Müller, S.
2002
Discrete-to-continuum limit of magnetic forces. Zbl 1038.74018
Müller, Stefan; Schlömerkemper, Anja
2002
A compactness result in the gradient theory of phase transitions. Zbl 0986.49009
DeSimone, Antonio; Müller, Stefan; Kohn, Robert V.; Otto, Felix
2001
A new approach to variational problems with multiple scales. Zbl 1021.49012
Alberti, Giovanni; Müller, Stefan
2001
Optimal existence theorems for nonhomogeneous differential inclusions. Zbl 0989.49012
Müller, S.; Sychev, M. A.
2001
Two-dimensional modelling of soft ferromagnetic films. Zbl 1065.74028
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix; Schäfer, Rudolf
2001
Uniqueness and maximal regularity for nonlinear elliptic systems of $$n$$-Laplace type with measure valued right hand side. Zbl 0937.35065
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
2000
Rigourous bounds for the Föppl-von Kármán theory of isotropically compressed plates. Zbl 1015.74029
Ben Belgacem, H.; Conti, S.; DeSimone, A.; Müller, S.
2000
Magnetic microstructures – a paradigm of multiscale problems. Zbl 0991.82038
DeSimone, Antonio; Kohn, Robert V.; Müller, Stefan; Otto, Felix
2000
The two-well problem in three dimensions. Zbl 0956.74039
Dolzmann, Georg; Kirchheim, Bernd; Müller, Stefan; Šverák, Vladimir
2000
Quasiconvexity is not invariant under transposition. Zbl 0980.49017
Müller, Stefan
2000
Variational models for microstructure and phase transitions. Zbl 0968.74050
Müller, Stefan
1999
$$\mathcal A$$-quasiconvexity, lower semicontinuity, and Young measures. Zbl 0940.49014
Fonseca, Irene; Müller, Stefan
1999
Convex integration with constraints and applications to phase transitions and partial differential equations. Zbl 0953.35042
Müller, S.; Šverák, V.
1999
Rank-one convexity implies quasiconvexity on diagonal matrices. Zbl 1055.49506
Müller, Stefan
1999
A sharp version of Zhang’s theorem on truncating sequences of gradients. Zbl 0942.49013
Müller, Stefan
1999
Sharp stability results for almost conformal maps in even dimensions. Zbl 0966.35016
Müller, Stefan; Šverák, Vladimir; Yan, Baisheng
1999
An isoperimetric estimate and $$W^{1,p}$$-quasiconvexity in nonlinear elasticity. Zbl 0929.74013
Müller, Stefan; Sivaloganathan, Jeyabal; Spector, Scott J.
1999
Concentration of low energy extremals. Zbl 0938.35042
Flucher, M.; Müller, S.
1999
Analysis of concentration and oscillation effects generated by gradients. Zbl 0920.49009
Fonseca, Irene; Müller, Stefan; Pedregal, Pablo
1998
Unexpected solutions of first and second order partial differential equations. Zbl 0896.35029
1998
Weak compactness of wave maps and harmonic maps. Zbl 0924.58011
Freire, Alexandre; Müller, Stefan; Struwe, Michael
1998
Radial symmetry and decay rate of variational ground states in the zero mass case. Zbl 0908.35005
Flucher, M.; Müller, S.
1998
Spatially discrete wave maps on (1+2)-dimensional space-time. Zbl 0933.58020
Müller, Stefan; Struwe, Michael
1998
Microstructures, phase transitions and geometry. Zbl 0908.49014
Müller, Stefan
1998
Nonlinear elliptic systems with measure-valued right hand side. Zbl 0895.35029
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
1997
The $$p$$-harmonic system with measure-valued right hand side. Zbl 0879.35052
Dolzmann, Georg; Hungerbühler, Norbert; Müller, Stefan
1997
Weak convergence of wave maps from $$(1+2)$$-dimensional Minkowski space to Riemannian manifolds. Zbl 0906.35061
Freire, Alexandre; Müller, Stefan; Struwe, Michael
1997
Harmonic maps on planar lattices. Zbl 1004.58007
Müller, Stefan; Struwe, Michael; Šverák, Vladimir
1997
Attainment results for the two-well problem by convex integration. Zbl 0930.35038
1996
Invertibility and a topological property of Sobolev maps. Zbl 0855.73028
Müller, Stefan; Spector, Scott J.; Tang, Qi
1996
Global existence of wave maps in 1+2 dimensions with finite energy data. Zbl 0896.35086
Müller, Stefan; Struwe, Michael
1996
An existence theory for nonlinear elasticity that allows for cavitation. Zbl 0836.73025
Müller, Stefan; Spector, Scott J.
1995
...and 28 more Documents
all top 5
#### Cited by 1,801 Authors
65 Conti, Sergio 58 Müller, Stefan 35 Fonseca, Irene 27 Ciarlet, Philippe Gaston 27 Ortiz, Michael 24 Iwaniec, Tadeusz 24 Mardare, Cristinel 22 Dolzmann, Georg 21 Kružík, Martin 20 Hornung, Peter 20 Mingione, Giuseppe 20 Otto, Felix 19 Yan, Baisheng 18 Braides, Andrea 18 Ignat, Radu 18 Yang, Dachun 17 DeSimone, Antonio 17 Garroni, Adriana 17 Mora, Maria Giovanna 17 Pruchnicki, Erick 16 De Lellis, Camillo 16 Kohn, Robert Vita 16 Paroni, Roberto 16 Pedregal, Pablo 16 Ponte Castañeda, Pedro 15 Bartels, Sören 15 Fusco, Nicola 15 Lewicka, Marta 15 Mora-Corral, Carlos 15 Schmidt, Bernd 15 Stefanelli, Ulisse 14 Harutyunyan, Davit 14 Lopez-Pamies, Oscar 14 Velčić, Igor 14 Zhang, Kewei 13 Carstensen, Carsten 13 Dacorogna, Bernard 13 Henao, Duvan A. 13 Kristensen, Jan 13 Krömer, Stefan 13 Mielke, Alexander 13 Onninen, Jani 13 Rindler, Filip 13 Székelyhidi, László jun. 12 Faraco, Daniel 12 Friedrich, Manuel 12 Griso, Georges 12 Leoni, Giovanni 12 Neff, Patrizio 12 Rivière, Tristan 12 Schlömerkemper, Anja 12 Serfaty, Sylvia 12 Sivaloganathan, Jeyabal 12 Zappale, Elvira 11 Cianchi, Andrea 11 Dal Maso, Gianni 11 Hencl, Stanislav 11 James, Richard D. 11 Maggi, Francesco 11 Malý, Jan 11 Muratov, Cyrill B. 11 Olbermann, Heiner 11 Palombaro, Mariapia 11 Ponsiglione, Marcello 11 Spector, Scott J. 10 Bevan, Jonathan J. 10 Blanchard, Dominique 10 Gaudiello, Antonio 10 Miehe, Christian 10 Neukamm, Stefan 10 Roubíček, Tomáš 10 Steigmann, David J. 10 Triantafyllidis, Nicolas 9 Bella, Peter 9 De Philippis, Guido 9 Focardi, Matteo 9 Friesecke, Gero 9 Gloria, Antoine 9 Lorent, Andrew 9 Marcellini, Paolo 9 Pakzad, Mohammad Reza 9 Rüland, Angkana 9 Rumpf, Martin 9 Zwicknagl, Barbara Maria 8 Alicandro, Roberto 8 Benešová, Barbora 8 Cicalese, Marco 8 Francfort, Gilles A. 8 Grabovsky, Yury 8 Jiu, Quansen 8 Kim, Seick 8 Kim, Seonghak 8 Knüpfer, Hans 8 Kreisbeck, Carolin 8 Mandallena, Jean-Philippe 8 Michaille, Gérard 8 Wei, Juncheng 8 Zeppieri, Caterina Ida 7 Agostiniani, Virginia 7 Ansini, Nadia ...and 1,701 more Authors
all top 5
#### Cited in 261 Serials
179 Archive for Rational Mechanics and Analysis 132 Calculus of Variations and Partial Differential Equations 91 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 69 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 66 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 62 Journal of the Mechanics and Physics of Solids 57 Journal of Elasticity 51 Journal de Mathématiques Pures et Appliquées. Neuvième Série 50 Journal of Differential Equations 48 Comptes Rendus. Mathématique. Académie des Sciences, Paris 45 Computer Methods in Applied Mechanics and Engineering 44 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 42 Mathematics and Mechanics of Solids 41 SIAM Journal on Mathematical Analysis 38 Journal of Mathematical Analysis and Applications 37 Journal of Functional Analysis 32 Journal of Nonlinear Science 25 Communications in Mathematical Physics 23 Communications on Pure and Applied Mathematics 22 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 21 Advances in Calculus of Variations 19 Continuum Mechanics and Thermodynamics 18 Proceedings of the American Mathematical Society 16 The Journal of Geometric Analysis 15 Annali di Matematica Pura ed Applicata. Serie Quarta 14 Mathematische Annalen 14 Transactions of the American Mathematical Society 13 NoDEA. Nonlinear Differential Equations and Applications 12 Mathematical Methods in the Applied Sciences 12 Manuscripta Mathematica 12 Physica D 12 Communications in Partial Differential Equations 12 Communications in Contemporary Mathematics 12 Analysis and Applications (Singapore) 11 Applicable Analysis 11 Advances in Mathematics 11 Bulletin of the American Mathematical Society. New Series 11 Journal of the European Mathematical Society (JEMS) 11 Communications on Pure and Applied Analysis 10 Journal of Computational Physics 10 Discrete and Continuous Dynamical Systems. Series S 9 International Journal of Engineering Science 9 Inventiones Mathematicae 8 Journal of Mathematical Physics 8 Journal of Statistical Physics 8 ZAMP. Zeitschrift für angewandte Mathematik und Physik 8 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 8 Meccanica 8 Ricerche di Matematica 8 SIAM Journal on Numerical Analysis 8 Discrete and Continuous Dynamical Systems 8 Proceedings of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 8 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 8 GAMM-Mitteilungen 7 Mathematische Zeitschrift 7 Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Serie IX. Rendiconti Lincei. Matematica e Applicazioni 7 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie V 7 Science China. Mathematics 6 Journal d’Analyse Mathématique 6 Nonlinearity 6 The Annals of Probability 6 International Journal for Numerical Methods in Engineering 6 Journal of Optimization Theory and Applications 6 Numerische Mathematik 6 Acta Mathematicae Applicatae Sinica. English Series 6 Computational Mechanics 6 Proceedings of the Royal Society of London. A. Mathematical, Physical and Engineering Sciences 5 Applied Mathematics and Optimization 5 Duke Mathematical Journal 5 Quarterly of Applied Mathematics 5 Zeitschrift für Analysis und ihre Anwendungen 5 Chinese Annals of Mathematics. Series B 5 Journal of the American Mathematical Society 5 ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik 5 European Journal of Mechanics. A. Solids 5 Acta Mathematica Sinica. English Series 5 Nonlinear Analysis. Real World Applications 5 Multiscale Modeling & Simulation 5 Analysis & PDE 5 Nonlinear Analysis. Theory, Methods & Applications 4 Computers & Mathematics with Applications 4 International Journal of Solids and Structures 4 Mathematics of Computation 4 Journal für die Reine und Angewandte Mathematik 4 Probability Theory and Related Fields 4 SIAM Journal on Applied Mathematics 4 Revista Matemática Complutense 4 Journal of Mathematical Fluid Mechanics 4 Annals of Mathematics. Second Series 4 Interfaces and Free Boundaries 4 M2AN. Mathematical Modelling and Numerical Analysis. ESAIM, European Series in Applied and Industrial Mathematics 4 Journal of Fixed Point Theory and Applications 4 Networks and Heterogeneous Media 4 Journal of Elliptic and Parabolic Equations 3 Arkiv för Matematik 3 Journal of Computational and Applied Mathematics 3 Mathematische Nachrichten 3 Siberian Mathematical Journal 3 Annals of Global Analysis and Geometry 3 Revista Matemática Iberoamericana ...and 161 more Serials
all top 5
#### Cited in 51 Fields
888 Mechanics of deformable solids (74-XX) 837 Partial differential equations (35-XX) 683 Calculus of variations and optimal control; optimization (49-XX) 189 Statistical mechanics, structure of matter (82-XX) 141 Functional analysis (46-XX) 137 Differential geometry (53-XX) 103 Fluid mechanics (76-XX) 98 Real functions (26-XX) 88 Numerical analysis (65-XX) 81 Global analysis, analysis on manifolds (58-XX) 59 Functions of a complex variable (30-XX) 58 Optics, electromagnetic theory (78-XX) 53 Harmonic analysis on Euclidean spaces (42-XX) 53 Operator theory (47-XX) 43 Probability theory and stochastic processes (60-XX) 42 Measure and integration (28-XX) 26 Convex and discrete geometry (52-XX) 25 Potential theory (31-XX) 25 Dynamical systems and ergodic theory (37-XX) 23 Ordinary differential equations (34-XX) 20 Biology and other natural sciences (92-XX) 18 Mechanics of particles and systems (70-XX) 14 Quantum theory (81-XX) 13 Classical thermodynamics, heat transfer (80-XX) 11 Computer science (68-XX) 11 Operations research, mathematical programming (90-XX) 9 Linear and multilinear algebra; matrix theory (15-XX) 8 Approximations and expansions (41-XX) 8 Manifolds and cell complexes (57-XX) 8 Systems theory; control (93-XX) 8 Information and communication theory, circuits (94-XX) 6 Integral equations (45-XX) 6 Algebraic topology (55-XX) 5 Several complex variables and analytic spaces (32-XX) 5 Difference and functional equations (39-XX) 4 General and overarching topics; collections (00-XX) 4 History and biography (01-XX) 4 Statistics (62-XX) 4 Relativity and gravitational theory (83-XX) 4 Geophysics (86-XX) 4 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 3 Abstract harmonic analysis (43-XX) 2 Combinatorics (05-XX) 2 Geometry (51-XX) 2 General topology (54-XX) 1 Nonassociative rings and algebras (17-XX) 1 Special functions (33-XX) 1 Sequences, series, summability (40-XX) 1 Integral transforms, operational calculus (44-XX) 1 Astronomy and astrophysics (85-XX) 1
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-06-21T20:25:51 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5907214879989624, "perplexity": 9979.752931220386}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623488289268.76/warc/CC-MAIN-20210621181810-20210621211810-00048.warc.gz"}
|
https://pdglive.lbl.gov/DataBlock.action?node=Q007NN1
|
#### ${{\boldsymbol t}}{{\overline{\boldsymbol t}}}$ Production Cross Section in Nucleus-Nucleus Collisions
VALUE ($\mu$barn) DOCUMENT ID TECN COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
$2.03$ ${}^{+0.71}_{-0.64}$ 1
2020 BC
CMS ${}^{}\mathrm {Pb}-{}^{}\mathrm {Pb}$ collisions, dilepton + ${{\mathit b}}$-jets
$2.54$ ${}^{+0.84}_{-0.74}$ 2
2020 BC
CMS ${}^{}\mathrm {Pb}-{}^{}\mathrm {Pb}$ collisions, dilepton only
1 SIRUNYAN 2020BC based on ($1.7$ $\pm0.1$) nb${}^{-1}$ of lead-lead collision data at a nucleon-nucleon c.m. energy of 5.02 TeV. It makes use of the final-state dilepton kinematic properties together with requirements on the number of ${{\mathit b}}$-jets. The measured value is compatible with QCD predictions.
2 SIRUNYAN 2020BC based on ($1.7$ $\pm0.1$) nb${}^{-1}$ of lead-lead collision data at a nucleon-nucleon c.m. energy of 5.02 TeV. It makes use of the final-state dilepton kinematic properties alone. The measured value is compatible with QCD predictions.
References:
SIRUNYAN 2020BC
PRL 125 222001 Evidence for Top Quark Production in Nucleus-Nucleus Collisions
| 2022-01-18T19:00:05 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7967477440834045, "perplexity": 10960.738746938889}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320300997.67/warc/CC-MAIN-20220118182855-20220118212855-00710.warc.gz"}
|
https://www.khanacademy.org/computing/computer-science/algorithms/breadth-first-search/a/the-breadth-first-search-algorithm
|
Breadth-first search assigns two values to each vertex $v$:
• A distance, giving the minimum number of edges in any path from the source vertex to vertex $v$.
• The predecessor vertex of $v$ along some shortest path from the source vertex. The source vertex's predecessor is some special value, such as null, indicating that it has no predecessor.
If there is no path from the source vertex to vertex $v$, then $v$'s distance is infinite and its predecessor has the same special value as the source's predecessor.
For example, here's an undirected graph with eight vertices, numbered 0 to 7, with vertex numbers appearing above or below the vertices. Inside each vertex are two numbers: its distance from the source, which is vertex 3, followed by its predecessor on a shortest path from vertex 3. A dash indicates null:
In BFS, we initially set the distance and predecessor of each vertex to the special value (null). We start the search at the source and assign it a distance of 0. Then we visit all the neighbors of the source and give each neighbor a distance of 1 and set its predecessor to be the source. Then we visit all the neighbors of the vertices whose distance is 1 and that have not been visited before, and we give each of these vertices a distance of 2 and set its predecessor to be vertex from which we visited it. We keep going until all vertices reachable from the source vertex have been visited, always visiting all vertices at distance $k$ from the source before visiting any vertex at distance $k+1$.
Given the example above, here are the steps plus a visualization to play through each step:
• Start by visiting vertex 3, the source, setting its distance to 0.
• Then visit vertices 2 and 6, setting their distance to 1 and their predecessor to vertex 3.
• Start visiting from vertices at distance 1 from the source, beginning with vertex 2. From vertex 2, visit vertices 4 and 5, setting their distance to 2 and their predecessor to vertex 2. Don't visit vertex 3, because it has already been visited.
• From vertex 6, don't visit vertex 5, because it was just visited from vertex 2, and don't visit vertex 3, either.
• Now start visiting from vertices at distance 2 from the source. Start by visiting from vertex 4. Vertex 2 has already been visited. Visit vertex 1, setting its distance to 3 and its predecessor to vertex 4.
• From vertex 5, don't visit any of its neighbors, because they have all been visited.
• Now start visiting from vertices at distance 3 from the source. The only such vertex is vertex 1. Its neighbors, vertices 4 and 5, have already been visited. But vertex 0 has not. Visit vertex 0, setting its distance to 4 and its predecessor to vertex 1.
• Now start visiting from vertices at distance 4 from the source. That's just vertex 0, and its neighbor, vertex 1, has already been visited. We're done!
Notice that because there is no path from vertex 3 to vertex 7, the search never visits vertex 7. Its distance and predecessor remain unchanged from their initial values of null.
A couple of questions come up. One is how to determine whether a vertex has been visited already. That's easy: a vertex's distance is null until it has been visited, at which time it gets a numeric value for its distance. Therefore, when we examine the neighbors of a vertex, we visit only the neighbors whose distance is currently null.
The other question is how to keep track of which vertices have already been visited but have not yet been visited from. We use a queue, which is a data structure that allows us to insert and remove items, where the item removed is always the one that has been in the queue the longest. We call this behavior first in, first out. A queue has three operations:
• enqueue(obj) inserts an object into the queue.
• dequeue() removes from the queue the object that has been in it the longest, returning this object.
• isEmpty() returns true if the queue currently contains no objects, and false if the queue contains at least one object.
Whenever we first visit any vertex, we enqueue it. At the start, we enqueue the source vertex because that's always the first vertex we visit. To decide which vertex to visit next, we choose the vertex that has been in the queue the longest and remove it from the queue—in other words, we use the vertex that's returned from dequeue(). Given our example graph, here's what the queue looks like for each step, plus the previous visualization shown with the queue state:
• Initially, the queue contains just vertex 3 with distance 0.
• Dequeue vertex 3, and enqueue vertices 2 and 6, both with distance 1. The queue now contains vertex 2 with distance 1 and vertex 6 with distance 1.
• Dequeue vertex 2, and enqueue vertices 4 and 5, both with distance 2. The queue now contains vertex 6 with distance 1, vertex 4 with distance 2, and vertex 5 with distance 2.
• Dequeue vertex 6, and don't enqueue any vertices. The queue now contains vertex 4 with distance 2 and vertex 5 with distance 2.
• Dequeue vertex 4, and enqueue vertex 1 with distance 3. The queue now contains vertex 5 with distance 2 and vertex 1 with distance 3.
• Dequeue vertex 5, and don't enqueue any vertices. The queue now contains just vertex 1 with distance 3.
• Dequeue vertex 1, and enqueue vertex 0 with distance 4. The queue now contains just vertex 0 with distance 4.
• Dequeue vertex 0, and don't enqueue any vertices. The queue is now empty. Because the queue is empty, breadth-first search terminates.
Notice that at each moment, the queue either contains vertices all with the same distance, or it contains vertices with distance $k$ followed by vertices with distance $k+1$. That's how we ensure that we visit all vertices at distance $k$ before visiting any vertices at distance $k+1$.
This content is a collaboration of Dartmouth Computer Science professors Thomas Cormen and Devin Balkcom, plus the Khan Academy computing curriculum team. The content is licensed CC-BY-NC-SA.
| 2019-01-21T03:21:09 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 11, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2974270284175873, "perplexity": 661.3193733236808}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583755653.69/warc/CC-MAIN-20190121025613-20190121051613-00116.warc.gz"}
|
https://zbmath.org/authors/?s=0&q=Seress%2C+Akos
|
# zbMATH — the first resource for mathematics
## Seress, Ákos
Compute Distance To:
Author ID: seress.akos Published as: Seress, Ákos; Seress, Á.; Seress, Akos; Seress, A. External Links: MacTutor · MGP · Wikidata · dblp · GND · IdRef
Documents Indexed: 114 Publications since 1983, including 6 Books Biographic References: 1 Publication
all top 5
#### Co-Authors
24 single-authored 15 Praeger, Cheryl Elisabeth 12 Li, Caiheng 10 Babai, László 7 Kantor, William M. 6 Niemeyer, Alice C. 5 Beals, Robert M. 4 Blokhuis, Aart 4 Erdős, Péter L. 4 Furedi, Zoltan 4 Giudici, Michael 4 Luks, Eugene M. 4 Székely, László A. 3 Burness, Timothy C. 3 Helfgott, Harald Andrés 3 Leedham-Green, Charles R. 3 Szabó, Tibor 3 Trofimov, Vladimir Ivanovich 2 Brooksbank, Peter A. 2 Cooperman, Gene 2 Dixon, John D. 2 Finkelstein, Larry A. 2 Friedman, Harvey M. 2 Hulpke, Alexander Jörg 2 Ivanov, Alexander A. 2 Lovász, László 2 Mehta, Nishali 2 Shalev, Aner 2 Swartz, Eric 2 Weisz, Iván 2 Wilbrink, Hendrikus Adrianus 1 Ankaralioglu, Nurullah 1 Arasu, Krishnasamy Thiru 1 Balogh, József 1 Bamberg, John 1 Bezrukov, Sergej L. 1 Calderbank, Arthur Robert 1 Chen, Jing 1 Devillers, Alice 1 Erdős, Pál 1 Fujita, Shinya 1 Gill, Nick 1 Gluck, David 1 Gyárfás, András 1 Hajnal, András 1 Harper, Lawrence H. 1 Hayes, Thomas P. 1 Jin, Wei 1 Katona, Gyula O. H. 1 Komjáth, Péter 1 Law, Maska 1 Lazebnik, Felix 1 Liebler, Robert A. 1 Magaard, Kay 1 Magnant, Colton 1 Mann, Avinoam 1 Metsch, Klaus 1 Miklós, Dezső 1 Neunhöffer, Max 1 Newmann, Mark J. 1 Niu, Liang 1 O’Brien, Eamonn A. 1 Pálfy, Péter Pál 1 Pasechnik, Dmitrii V. 1 Penttila, Tim 1 Puliyambalath, Naushad Pasha 1 Pyber, László 1 Qin, Hongxun 1 Reimer, David 1 Robertson, Edmund Frederick 1 Rodl, Vojtech 1 Schönert, Martin 1 Shpectorov, Sergey Viktorovich 1 Solomon, Ronald Mark 1 Song, Shujiao 1 Spiga, Pablo 1 Szegedy, Mario 1 Thomas, Anne 1 Ustimenko, Vasiliy A. 1 West, Douglas Brent 1 Woldar, Andrew J. 1 Wong, Tsai-Lien 1 Yalçınkaya, Şükrü 1 Yang, Keyan 1 Zhu, Xuding 1 Żuk, Andrzej
all top 5
#### Serials
10 Journal of Algebra 6 Journal of Combinatorial Theory. Series A 4 Discrete Mathematics 4 Graphs and Combinatorics 3 Bulletin of the London Mathematical Society 3 Journal of Combinatorial Theory. Series B 3 Journal of Graph Theory 3 European Journal of Combinatorics 3 Combinatorica 3 Designs, Codes and Cryptography 3 Annals of Combinatorics 2 Advances in Mathematics 2 Proceedings of the American Mathematical Society 2 Transactions of the American Mathematical Society 2 Combinatorics, Probability and Computing 2 The Electronic Journal of Combinatorics 2 Journal of Group Theory 2 Discrete Mathematics and Theoretical Computer Science. DMTCS 2 Ohio State University Mathematical Research Institute Publications 1 Israel Journal of Mathematics 1 Journal of Combinatorics, Information & System Sciences 1 Journal of Computer and System Sciences 1 Journal of the London Mathematical Society. Second Series 1 Journal of Pure and Applied Algebra 1 Journal für die Reine und Angewandte Mathematik 1 Matematikai Lapok 1 Mathematische Zeitschrift 1 Memoirs of the American Mathematical Society 1 SIAM Journal on Computing 1 Studia Scientiarum Mathematicarum Hungarica 1 Theoretical Computer Science 1 Acta Applicandae Mathematicae 1 Discrete & Computational Geometry 1 SIAM Journal on Discrete Mathematics 1 Linear Algebra and its Applications 1 Notices of the American Mathematical Society 1 Journal of Algebraic Combinatorics 1 Journal of Combinatorial Designs 1 Annals of Mathematics. Second Series 1 LMS Journal of Computation and Mathematics 1 Journal of the Australian Mathematical Society 1 Cambridge Tracts in Mathematics 1 Groups, Geometry, and Dynamics
all top 5
#### Fields
64 Group theory and generalizations (20-XX) 52 Combinatorics (05-XX) 29 Computer science (68-XX) 7 Geometry (51-XX) 7 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 5 Information and communication theory, circuits (94-XX) 4 General and overarching topics; collections (00-XX) 3 History and biography (01-XX) 3 Order, lattices, ordered algebraic structures (06-XX) 3 Number theory (11-XX) 2 Mathematical logic and foundations (03-XX) 2 Nonassociative rings and algebras (17-XX) 2 Operations research, mathematical programming (90-XX) 1 General topology (54-XX) 1 Probability theory and stochastic processes (60-XX) 1 Systems theory; control (93-XX)
#### Citations contained in zbMATH Open
91 Publications have been cited 737 times in 484 Documents Cited by Year
Permutation group algorithms. Zbl 1028.20002
Seress, Ákos
2003
On the diameter of permutation groups. Zbl 0783.20001
Babai, László; Seress, Ákos
1992
Prime power graphs for groups of Lie type. Zbl 0997.20018
Kantor, William M.; Seress, Ákos
2002
The minimal base size of primitive solvable permutation groups. Zbl 0854.20004
Seress, Ákos
1996
Black box classical groups. Zbl 1053.20045
Kantor, William M.; Seress, Ákos
2001
Majorana representations of the symmetric group of degree 4. Zbl 1257.20011
Ivanov, A. A.; Pasechnik, D. V.; Seress, Á.; Shpectorov, S.
2010
Primitive groups with no regular orbits on the set of subsets. Zbl 0892.20002
Seress, Ákos
1997
Large element orders and the characteristic of Lie-type simple groups. Zbl 1180.20009
Kantor, William M.; Seress, Ákos
2009
On the diameter of Cayley graphs of the symmetric group. Zbl 0649.20002
Babai, Lászlo; Seress, Ákos
1988
A black-box group algorithm for recognizing finite symmetric and alternating groups. I. Zbl 1022.20004
Beals, Robert; Leedham-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2003
Coloring graphs with locally few colors. Zbl 0591.05030
Erdős, Paul; Füredi, Z.; Hajnal, András; Komjáth, P.; Rödl, Vojtěch; Seress, Á.
1986
Black-box recognition of finite simple groups of Lie type by statistics of element orders. Zbl 1015.20013
Babai, László; Kantor, William M.; Pálfy, Péter P.; Seress, Ákos
2002
Polynomial-time theory of matrix groups. Zbl 1304.68065
Babai, László; Beals, Robert; Seress, Ákos
2009
On the diameter of permutation groups. Zbl 1295.20027
Helfgott, Harald A.; Seress, Ákos
2014
Fast Monte Carlo algorithms for permutation groups. Zbl 0834.20002
Babai, László; Cooperman, Gene; Finkelstein, Larry; Luks, Eugene; Seress, Ákos
1995
Residual properties of free groups and probabilistic methods. Zbl 1027.20013
Dixon, John D.; Pyber, László; Seress, Ákos; Shalev, Aner
2003
Permutations with restricted cycle structure and an algorithmic application. Zbl 1012.60009
Beals, Robert; Leedhan-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2002
Square-free non-Cayley numbers. On vertex-transitive non-Cayley graphs of square-free order. Zbl 1075.20002
Li, Cai Heng; Seress, Ákos
2005
Hajnal’s triangle-free game and extremal graph problems. Zbl 0764.05043
Füredi, Zoltán; Reimer, Dave; Seress, Ákos
1991
On vertex-transitive, non-Cayley graphs of order $$pqr$$. Zbl 0908.05050
Seress, Ákos
1998
Short presentations for three-dimensional unitary groups. Zbl 1062.20052
Hulpke, Alexander; Seress, Ákos
2001
The primitve permutation groups of squarefree degree. Zbl 1043.20001
Li, Cai Heng; Seress, Ákos
2003
Graphs of prescribed girth and bi-degree. Zbl 0828.05034
Füredi, Z.; Lazebnik, F.; Seress, Á.; Ustimenko, V. A.; Woldar, A. J.
1995
A data structure for a uniform approach to computations with finite groups. Zbl 1356.68291
Neunhöffer, Max; Seress, Ákos
2006
On the diameter of the symmetric group: polynomial bounds. Zbl 1318.20002
Babai, László; Beals, Robert; Seress, Ákos
2004
On Hajnal’s triangle-free game. Zbl 0757.90096
Seress, Ákos
1992
Majorana representations of $$A_5$$. Zbl 1260.20019
Ivanov, A. A.; Seress, Á.
2012
Large families of cospectral graphs. Zbl 0972.05033
Seress, Ákos
2000
On sets of points in $$PG(2,q)$$ without tangents. Zbl 0742.51007
Blokhuis, A.; Seress, Á.; Wilbrink, H. A.
1991
Bases for primitive permutation groups and a conjecture of Babai. Zbl 0897.20005
Gluck, David; Seress, Ákos; Shalev, Aner
1998
Finding blocks of imprimitivity in small-base groups in nearly linear time. Zbl 0925.20009
Schönert, Martin; Seress, Ákos
1994
On the degree of transitivity of permutation groups: A short proof. Zbl 0616.20002
Babai, László; Seress, Ákos
1987
Computing with matrix groups. Zbl 1052.20001
Kantor, William M.; Seress, Ákos
2003
$$s$$-arc-transitive graphs and normal subgroups. Zbl 1301.05172
Li, Cai Heng; Seress, Ákos; Song, Shu Jiao
2015
Random generators of the symmetric group: diameter, mixing time and spectral gap. Zbl 1310.20003
Helfgott, Harald A.; Seress, Ákos; Zuk, Andrzej
2015
On Pyber’s base size conjecture. Zbl 1316.20001
Burness, Timothy C.; Seress, Ákos
2015
Constructions of quasiprimitive two-arc transitive graphs of product action type. Zbl 1100.05047
Li, Cai Heng; Seress, Ákos
2006
Probabilistic generation of finite classical groups in odd characteristic by involutions. Zbl 1244.20044
Praeger, Cheryl E.; Seress, Ákos
2011
Constructive recognition of finite alternating and symmetric groups acting as matrix groups on their natural permutation modules. Zbl 1107.20012
Beals, Robert; Leedham-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2005
Maximal triangle-free graphs with restrictions on the degrees. Zbl 0787.05054
Füredi, Zoltán; Seress, Ákos
1994
Fast management of permutation groups. I. Zbl 0885.68090
Babai, László; Luks, Eugene M.; Seress, Ákos
1997
Recognition of small dimensional representations of general linear groups. Zbl 1216.20005
Magaard, Kay; O’Brien, E. A.; Seress, Ákos
2008
Symmetrical path-cycle covers of a graph and polygonal graphs. Zbl 1109.05053
Li, Cai Heng; Seress, Ákos
2007
Toward the classification of $$s$$-arc transitive graphs. Zbl 1121.05062
Seress, Ákos
2007
Extremely primitive groups. Zbl 1141.20003
Mann, Avinoam; Praeger, Cheryl E.; Seress, Ákos
2007
Polygonal graphs. Zbl 1170.05317
Seress, Ákos
2008
Connected, bounded degree, triangle avoidance games. Zbl 1229.05210
Mehta, Nishali; Seress, Ákos
2011
Bounds on the diameter of Cayley graphs of the symmetric group. Zbl 1297.05107
Bamberg, John; Gill, Nick; Hayes, Thomas P.; Helfgott, Harald A.; Seress, Ákos; Spiga, Pablo
2014
Erdős-Ko-Rado and Hilton-Milner type theorems for intersecting chains in posets. Zbl 0949.05081
Erdős, Péter L.; Seress, Ákos; Székely, László A.
2000
An introduction to computational group theory. Zbl 0929.20001
Seress, Ákos
1997
Extremely primitive classical groups. Zbl 1260.20003
Burness, Timothy C.; Praeger, Cheryl E.; Seress, Ákos
2012
Construction of 2-closed M-representations. Zbl 1323.68626
Seress, Ákos
2012
Quick gossiping without duplicate transmissions. Zbl 0601.05029
Seress, Ákos
1986
Extremely primitive sporadic and alternating groups. Zbl 1264.20001
Burness, Timothy C.; Praeger, Cheryl E.; Seress, Ákos
2012
On the bandwidth of 3-dimensional Hamming graphs. Zbl 1151.90038
Balogh, J.; Bezrukov, S. L.; Harper, L. H.; Seress, A.
2008
Computing the Fitting subgroup and solvable radical of small-base permutation groups in nearly linear time. Zbl 0878.20004
Luks, Eugene M.; Seress, Ákos
1997
Gossiping old ladies. Zbl 0518.05001
Seress, Akos
1983
The cocycle lattice of binary matroids. Zbl 0777.05040
Lovász, László; Seress, Ákos
1993
Permutation group algorithms via black box recognition algorithms. Zbl 0932.20006
Kantor, William M.; Seress, Ákos
1999
On minimal subdegrees of finite primitive permutation groups. Zbl 1111.20003
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir
2006
Estimation problems and randomised group algorithms. Zbl 1282.20001
Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2013
On orbit equivalent, two-step imprimitive permutation groups. Zbl 1171.20003
Seress, Ákos; Yang, Keyan
2008
A reduction algorithm for large-base primitive permutation groups. Zbl 1112.20005
Law, Maska; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2006
A note on the girth-doubling construction for polygonal graphs. Zbl 1229.05185
Seress, Ákos; Swartz, Eric
2011
Generation of finite classical groups by pairs of elements with large fixed point spaces. Zbl 1308.20045
Praeger, Cheryl E.; Seress, Ákos; Yalçınkaya, Şükrü
2015
Disconnected colors in generalized Gallai-colorings. Zbl 1272.05048
Fujita, Shinya; Gyárfás, András; Magnant, Colton; Seress, Ákos
2013
Strong involutions in finite special linear groups of odd characteristic. Zbl 1437.20041
Dixon, John D.; Praeger, Cheryl E.; Seress, Ákos
2018
All lambda-designs with $$\lambda = 2 p$$ are type-1. Zbl 0959.05021
Seress, Akos
2001
Decidability in elementary analysis. I. Zbl 0681.03005
Friedman, Harvey; Seress, Ákos
1989
Quick gossiping by conference calls. Zbl 0691.05033
Seress, Akos
1988
Some characterizations of type-1 $$\lambda$$-designs. Zbl 0696.05007
Seress, Ákos
1989
Characterization of complete exterior sets of conics. Zbl 0761.51006
Blokhuis, A.; Seress, Á.; Wilbrink, H. A.
1992
Dense graphs with cycle neighborhoods. Zbl 0820.05036
Seress, Ákos; Szabó, Tibor
1995
On limit graphs of finite vertex-primitive graphs. Zbl 1106.05046
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir I.
2007
Characterising vertex-star transitive and edge-star transitive graphs. Zbl 1309.05093
Giudici, Michael; Li, Cai Heng; Seress, Ákos; Thomas, Anne
2015
A reduction algorithm for matrix groups with an extraspecial normal subgroup. Zbl 1096.20041
Brooksbank, Peter; Niemeyer, Alice C.; Seress, Ákos
2006
A unified approach to computations with permutation and matrix groups. Zbl 1117.20001
Seress, Ákos
2006
A family of half-transitive graphs. Zbl 1266.05053
Chen, Jing; Li, Cai Heng; Seress, Ákos
2013
Regular semisimple elements and involutions in finite general linear groups of odd characteristic. Zbl 1282.20056
Praeger, Cheryl E.; Seress, Ákos
2012
The number of directions determined by points in the three-dimensional Euclidean space. Zbl 1020.51014
Blokhuis, Aart; Seress, Ákos
2002
On intersecting chains in Boolean algebras. Zbl 0806.06013
Erdös, Péter L.; Seress, Ákos; Székely, László A.
1994
Local 2-geodesic transitivity of graphs. Zbl 1297.05125
Devillers, Alice; Jin, Wei; Li, Cai Heng; Seress, Ákos
2014
Decidability in elementary analysis. II. Zbl 0698.03002
Friedman, Harvey; Seress, Ákos
1990
Nearly linear time algorithms for permutation groups with a small base. Zbl 0925.20011
Babai, László; Cooperman, Gene; Finkelstein, Larry; Seress, Ákos
1991
The cocycle lattice of binary matroids. II. Zbl 0835.05013
Lovász, László; Seress, Ákos
1995
Gossips by conference calls. Zbl 0535.05003
Seress, Ákos
1987
The vertex primitive and vertex bi-primitive $$s$$-arc regular graphs. Zbl 1209.05122
Li, Cai Heng; Niu, Liang; Seress, Ákos; Solomon, Ronald
2010
Computing tensor decompositions of finite matrix groups. Zbl 1286.68511
Ankaralioglu, Nurullah; Seress, Ákos
2011
Limits of vertex-transitive graphs. Zbl 1102.54019
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir
2006
A family of near-polygonal graphs of valency 10. Zbl 1256.05103
Seress, Ákos; Swartz, Eric
2012
Bounded degree, triangle avoidance graph games. Zbl 1267.91020
Mehta, Nishali; Seress, Ákos
2013
Strong involutions in finite special linear groups of odd characteristic. Zbl 1437.20041
Dixon, John D.; Praeger, Cheryl E.; Seress, Ákos
2018
$$s$$-arc-transitive graphs and normal subgroups. Zbl 1301.05172
Li, Cai Heng; Seress, Ákos; Song, Shu Jiao
2015
Random generators of the symmetric group: diameter, mixing time and spectral gap. Zbl 1310.20003
Helfgott, Harald A.; Seress, Ákos; Zuk, Andrzej
2015
On Pyber’s base size conjecture. Zbl 1316.20001
Burness, Timothy C.; Seress, Ákos
2015
Generation of finite classical groups by pairs of elements with large fixed point spaces. Zbl 1308.20045
Praeger, Cheryl E.; Seress, Ákos; Yalçınkaya, Şükrü
2015
Characterising vertex-star transitive and edge-star transitive graphs. Zbl 1309.05093
Giudici, Michael; Li, Cai Heng; Seress, Ákos; Thomas, Anne
2015
On the diameter of permutation groups. Zbl 1295.20027
Helfgott, Harald A.; Seress, Ákos
2014
Bounds on the diameter of Cayley graphs of the symmetric group. Zbl 1297.05107
Bamberg, John; Gill, Nick; Hayes, Thomas P.; Helfgott, Harald A.; Seress, Ákos; Spiga, Pablo
2014
Local 2-geodesic transitivity of graphs. Zbl 1297.05125
Devillers, Alice; Jin, Wei; Li, Cai Heng; Seress, Ákos
2014
Estimation problems and randomised group algorithms. Zbl 1282.20001
Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2013
Disconnected colors in generalized Gallai-colorings. Zbl 1272.05048
Fujita, Shinya; Gyárfás, András; Magnant, Colton; Seress, Ákos
2013
A family of half-transitive graphs. Zbl 1266.05053
Chen, Jing; Li, Cai Heng; Seress, Ákos
2013
Bounded degree, triangle avoidance graph games. Zbl 1267.91020
Mehta, Nishali; Seress, Ákos
2013
Majorana representations of $$A_5$$. Zbl 1260.20019
Ivanov, A. A.; Seress, Á.
2012
Extremely primitive classical groups. Zbl 1260.20003
Burness, Timothy C.; Praeger, Cheryl E.; Seress, Ákos
2012
Construction of 2-closed M-representations. Zbl 1323.68626
Seress, Ákos
2012
Extremely primitive sporadic and alternating groups. Zbl 1264.20001
Burness, Timothy C.; Praeger, Cheryl E.; Seress, Ákos
2012
Regular semisimple elements and involutions in finite general linear groups of odd characteristic. Zbl 1282.20056
Praeger, Cheryl E.; Seress, Ákos
2012
A family of near-polygonal graphs of valency 10. Zbl 1256.05103
Seress, Ákos; Swartz, Eric
2012
Probabilistic generation of finite classical groups in odd characteristic by involutions. Zbl 1244.20044
Praeger, Cheryl E.; Seress, Ákos
2011
Connected, bounded degree, triangle avoidance games. Zbl 1229.05210
Mehta, Nishali; Seress, Ákos
2011
A note on the girth-doubling construction for polygonal graphs. Zbl 1229.05185
Seress, Ákos; Swartz, Eric
2011
Computing tensor decompositions of finite matrix groups. Zbl 1286.68511
Ankaralioglu, Nurullah; Seress, Ákos
2011
Majorana representations of the symmetric group of degree 4. Zbl 1257.20011
Ivanov, A. A.; Pasechnik, D. V.; Seress, Á.; Shpectorov, S.
2010
The vertex primitive and vertex bi-primitive $$s$$-arc regular graphs. Zbl 1209.05122
Li, Cai Heng; Niu, Liang; Seress, Ákos; Solomon, Ronald
2010
Large element orders and the characteristic of Lie-type simple groups. Zbl 1180.20009
Kantor, William M.; Seress, Ákos
2009
Polynomial-time theory of matrix groups. Zbl 1304.68065
Babai, László; Beals, Robert; Seress, Ákos
2009
Recognition of small dimensional representations of general linear groups. Zbl 1216.20005
Magaard, Kay; O’Brien, E. A.; Seress, Ákos
2008
Polygonal graphs. Zbl 1170.05317
Seress, Ákos
2008
On the bandwidth of 3-dimensional Hamming graphs. Zbl 1151.90038
Balogh, J.; Bezrukov, S. L.; Harper, L. H.; Seress, A.
2008
On orbit equivalent, two-step imprimitive permutation groups. Zbl 1171.20003
Seress, Ákos; Yang, Keyan
2008
Symmetrical path-cycle covers of a graph and polygonal graphs. Zbl 1109.05053
Li, Cai Heng; Seress, Ákos
2007
Toward the classification of $$s$$-arc transitive graphs. Zbl 1121.05062
Seress, Ákos
2007
Extremely primitive groups. Zbl 1141.20003
Mann, Avinoam; Praeger, Cheryl E.; Seress, Ákos
2007
On limit graphs of finite vertex-primitive graphs. Zbl 1106.05046
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir I.
2007
A data structure for a uniform approach to computations with finite groups. Zbl 1356.68291
Neunhöffer, Max; Seress, Ákos
2006
Constructions of quasiprimitive two-arc transitive graphs of product action type. Zbl 1100.05047
Li, Cai Heng; Seress, Ákos
2006
On minimal subdegrees of finite primitive permutation groups. Zbl 1111.20003
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir
2006
A reduction algorithm for large-base primitive permutation groups. Zbl 1112.20005
Law, Maska; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2006
A reduction algorithm for matrix groups with an extraspecial normal subgroup. Zbl 1096.20041
Brooksbank, Peter; Niemeyer, Alice C.; Seress, Ákos
2006
A unified approach to computations with permutation and matrix groups. Zbl 1117.20001
Seress, Ákos
2006
Limits of vertex-transitive graphs. Zbl 1102.54019
Giudici, Michael; Li, Cai Heng; Praeger, Cheryl E.; Seress, Ákos; Trofimov, Vladimir
2006
Square-free non-Cayley numbers. On vertex-transitive non-Cayley graphs of square-free order. Zbl 1075.20002
Li, Cai Heng; Seress, Ákos
2005
Constructive recognition of finite alternating and symmetric groups acting as matrix groups on their natural permutation modules. Zbl 1107.20012
Beals, Robert; Leedham-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2005
On the diameter of the symmetric group: polynomial bounds. Zbl 1318.20002
Babai, László; Beals, Robert; Seress, Ákos
2004
Permutation group algorithms. Zbl 1028.20002
Seress, Ákos
2003
A black-box group algorithm for recognizing finite symmetric and alternating groups. I. Zbl 1022.20004
Beals, Robert; Leedham-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2003
Residual properties of free groups and probabilistic methods. Zbl 1027.20013
Dixon, John D.; Pyber, László; Seress, Ákos; Shalev, Aner
2003
The primitve permutation groups of squarefree degree. Zbl 1043.20001
Li, Cai Heng; Seress, Ákos
2003
Computing with matrix groups. Zbl 1052.20001
Kantor, William M.; Seress, Ákos
2003
Prime power graphs for groups of Lie type. Zbl 0997.20018
Kantor, William M.; Seress, Ákos
2002
Black-box recognition of finite simple groups of Lie type by statistics of element orders. Zbl 1015.20013
Babai, László; Kantor, William M.; Pálfy, Péter P.; Seress, Ákos
2002
Permutations with restricted cycle structure and an algorithmic application. Zbl 1012.60009
Beals, Robert; Leedhan-Green, Charles R.; Niemeyer, Alice C.; Praeger, Cheryl E.; Seress, Ákos
2002
The number of directions determined by points in the three-dimensional Euclidean space. Zbl 1020.51014
Blokhuis, Aart; Seress, Ákos
2002
Black box classical groups. Zbl 1053.20045
Kantor, William M.; Seress, Ákos
2001
Short presentations for three-dimensional unitary groups. Zbl 1062.20052
Hulpke, Alexander; Seress, Ákos
2001
All lambda-designs with $$\lambda = 2 p$$ are type-1. Zbl 0959.05021
Seress, Akos
2001
Large families of cospectral graphs. Zbl 0972.05033
Seress, Ákos
2000
Erdős-Ko-Rado and Hilton-Milner type theorems for intersecting chains in posets. Zbl 0949.05081
Erdős, Péter L.; Seress, Ákos; Székely, László A.
2000
Permutation group algorithms via black box recognition algorithms. Zbl 0932.20006
Kantor, William M.; Seress, Ákos
1999
On vertex-transitive, non-Cayley graphs of order $$pqr$$. Zbl 0908.05050
Seress, Ákos
1998
Bases for primitive permutation groups and a conjecture of Babai. Zbl 0897.20005
Gluck, David; Seress, Ákos; Shalev, Aner
1998
Primitive groups with no regular orbits on the set of subsets. Zbl 0892.20002
Seress, Ákos
1997
Fast management of permutation groups. I. Zbl 0885.68090
Babai, László; Luks, Eugene M.; Seress, Ákos
1997
An introduction to computational group theory. Zbl 0929.20001
Seress, Ákos
1997
Computing the Fitting subgroup and solvable radical of small-base permutation groups in nearly linear time. Zbl 0878.20004
Luks, Eugene M.; Seress, Ákos
1997
The minimal base size of primitive solvable permutation groups. Zbl 0854.20004
Seress, Ákos
1996
Fast Monte Carlo algorithms for permutation groups. Zbl 0834.20002
Babai, László; Cooperman, Gene; Finkelstein, Larry; Luks, Eugene; Seress, Ákos
1995
Graphs of prescribed girth and bi-degree. Zbl 0828.05034
Füredi, Z.; Lazebnik, F.; Seress, Á.; Ustimenko, V. A.; Woldar, A. J.
1995
Dense graphs with cycle neighborhoods. Zbl 0820.05036
Seress, Ákos; Szabó, Tibor
1995
The cocycle lattice of binary matroids. II. Zbl 0835.05013
Lovász, László; Seress, Ákos
1995
Finding blocks of imprimitivity in small-base groups in nearly linear time. Zbl 0925.20009
Schönert, Martin; Seress, Ákos
1994
Maximal triangle-free graphs with restrictions on the degrees. Zbl 0787.05054
Füredi, Zoltán; Seress, Ákos
1994
On intersecting chains in Boolean algebras. Zbl 0806.06013
Erdös, Péter L.; Seress, Ákos; Székely, László A.
1994
The cocycle lattice of binary matroids. Zbl 0777.05040
Lovász, László; Seress, Ákos
1993
On the diameter of permutation groups. Zbl 0783.20001
Babai, László; Seress, Ákos
1992
On Hajnal’s triangle-free game. Zbl 0757.90096
Seress, Ákos
1992
Characterization of complete exterior sets of conics. Zbl 0761.51006
Blokhuis, A.; Seress, Á.; Wilbrink, H. A.
1992
Hajnal’s triangle-free game and extremal graph problems. Zbl 0764.05043
Füredi, Zoltán; Reimer, Dave; Seress, Ákos
1991
On sets of points in $$PG(2,q)$$ without tangents. Zbl 0742.51007
Blokhuis, A.; Seress, Á.; Wilbrink, H. A.
1991
Nearly linear time algorithms for permutation groups with a small base. Zbl 0925.20011
Babai, László; Cooperman, Gene; Finkelstein, Larry; Seress, Ákos
1991
Decidability in elementary analysis. II. Zbl 0698.03002
Friedman, Harvey; Seress, Ákos
1990
Decidability in elementary analysis. I. Zbl 0681.03005
Friedman, Harvey; Seress, Ákos
1989
Some characterizations of type-1 $$\lambda$$-designs. Zbl 0696.05007
Seress, Ákos
1989
On the diameter of Cayley graphs of the symmetric group. Zbl 0649.20002
Babai, Lászlo; Seress, Ákos
1988
Quick gossiping by conference calls. Zbl 0691.05033
Seress, Akos
1988
On the degree of transitivity of permutation groups: A short proof. Zbl 0616.20002
Babai, László; Seress, Ákos
1987
Gossips by conference calls. Zbl 0535.05003
Seress, Ákos
1987
Coloring graphs with locally few colors. Zbl 0591.05030
Erdős, Paul; Füredi, Z.; Hajnal, András; Komjáth, P.; Rödl, Vojtěch; Seress, Á.
1986
Quick gossiping without duplicate transmissions. Zbl 0601.05029
Seress, Ákos
1986
Gossiping old ladies. Zbl 0518.05001
Seress, Akos
1983
all top 5
#### Cited by 602 Authors
36 Seress, Ákos 29 Praeger, Cheryl Elisabeth 18 Li, Caiheng 16 O’Brien, Eamonn A. 15 Shalev, Aner 12 Burness, Timothy C. 12 Leedham-Green, Charles R. 12 Liebeck, Martin Walter 10 Babai, László 10 Holt, Derek F. 10 Niemeyer, Alice C. 9 Giudici, Michael 9 Kantor, William M. 9 Vasil’ev, Andreĭ Viktorovich 7 Guralnick, Robert Michael 7 Helfgott, Harald Andrés 7 Ivanov, Alexander A. 7 Saxl, Jan 7 Spiga, Pablo 7 Swartz, Eric 6 Grechkoseeva, Mariya Aleksandrovna 6 Halasi, Zoltán 6 Hulpke, Alexander Jörg 6 Zhou, Jinxin 5 Bamberg, John 5 Brooksbank, Peter A. 5 Feng, Yanquan 5 Guest, Simon D. 5 Magaard, Kay 5 Marušič, Dragan 5 Roney-Dougal, Colva M. 5 Shi, Wujie 5 Simonyi, Gábor 5 Tiep Pham Huu 5 Woldar, Andrew J. 4 Arvind, Vikraman 4 Bäärnhielm, Henrik 4 Cameron, Peter Jephson 4 Dietrich, Heiko 4 Dolfi, Silvio 4 Gill, Nick 4 Glasby, Stephen Peter 4 Imrich, Wilfried 4 Li, Xianhua 4 Lübeck, Frank 4 Maróti, Attila 4 Morgan, Luke 4 Navarro, Gabriel 4 Pyber, László 4 Rehren, Felix 4 Shpectorov, Sergey Viktorovich 4 Tardos, Gábor 4 Ustimenko, Vasiliy A. 3 Alishahi, Meysam 3 Beals, Robert M. 3 Breuillard, Emmanuel 3 Buturlakin, Aleksandr Aleksandrovich 3 Cannon, John J. 3 Castillo-Ramirez, Alonso 3 Conder, Marston D. E. 3 Das, Bireswar 3 Dinai, Oren 3 Dobson, Edward 3 Hajiabolhassan, Hossein 3 Hall, Jonathan I. 3 Harper, Scott 3 Kassabov, Martin 3 Kutnar, Klavdija 3 Larsen, Michael Jeffrey 3 Lazebnik, Felix 3 Li, Jingjian 3 Lubotzky, Alexander 3 Lytkin, Daniil Vsevolodovich 3 Maglione, Joshua 3 McInroy, Justin F. 3 Nešetřil, Jaroslav 3 Ponomarenko, Ilya Nikolaevich 3 Qiao, Youming 3 Rowley, Peter J. 3 Ryba, Alexander J. E. 3 Staroletov, Alexey Mikhailovich 3 Thom, Andreas Berthold 3 Tucker, Thomas W. 3 Unger, William R. 3 Whybrow, Madeleine L. 3 Wilson, Robert Arnott 2 Abért, Miklós 2 Ankaralioglu, Nurullah 2 Araújo, João 2 Ball, Simeon 2 Ballester-Bolinches, Adolfo 2 Borg, Peter 2 Bors, Alexander 2 Bradford, Henry 2 Chen, Wenbing 2 Cheng, Xiaoyan 2 Csajbók, Bence 2 de Graaf, Willem Adriaan 2 Detinko, Alla S. 2 Devillers, Alice ...and 502 more Authors
all top 5
#### Cited in 115 Serials
69 Journal of Algebra 32 Discrete Mathematics 21 Transactions of the American Mathematical Society 20 Journal of Symbolic Computation 15 European Journal of Combinatorics 13 Discrete Applied Mathematics 13 Journal of Algebraic Combinatorics 13 Journal of Group Theory 12 Journal of Combinatorial Theory. Series A 10 Journal of Combinatorial Theory. Series B 10 Journal of Graph Theory 9 Graphs and Combinatorics 8 Siberian Mathematical Journal 7 Advances in Mathematics 6 Israel Journal of Mathematics 6 Proceedings of the American Mathematical Society 6 Theoretical Computer Science 6 The Electronic Journal of Combinatorics 6 LMS Journal of Computation and Mathematics 5 Mathematics of Computation 5 Archiv der Mathematik 5 Journal of Pure and Applied Algebra 5 Combinatorica 5 Linear Algebra and its Applications 5 Journal of Mathematical Sciences (New York) 5 Proceedings of the Steklov Institute of Mathematics 4 Communications in Algebra 4 SIAM Journal on Computing 4 Journal of the American Mathematical Society 4 Designs, Codes and Cryptography 4 Bulletin of the American Mathematical Society. New Series 4 Annals of Mathematics. Second Series 4 Journal of the European Mathematical Society (JEMS) 3 Algebra and Logic 3 Geometriae Dedicata 3 Mathematische Annalen 3 Combinatorics, Probability and Computing 3 Journal of Combinatorial Designs 3 Journal of the Australian Mathematical Society 2 Bulletin of the Australian Mathematical Society 2 Information Processing Letters 2 Mathematical Proceedings of the Cambridge Philosophical Society 2 Applied Mathematics and Computation 2 Czechoslovak Mathematical Journal 2 Inventiones Mathematicae 2 Journal of Computer and System Sciences 2 Memoirs of the American Mathematical Society 2 Proceedings of the Edinburgh Mathematical Society. Series II 2 Advances in Applied Mathematics 2 Algorithmica 2 SIAM Journal on Discrete Mathematics 2 International Journal of Algebra and Computation 2 International Journal of Foundations of Computer Science 2 Geometric and Functional Analysis. GAFA 2 Computational Complexity 2 Turkish Journal of Mathematics 2 Theory of Computing Systems 2 Annals of Combinatorics 2 Journal of Algebra and its Applications 2 Discrete Optimization 2 Sibirskie Èlektronnye Matematicheskie Izvestiya 2 Journal of Algebra, Combinatorics, Discrete Structures and Applications 1 Artificial Intelligence 1 Communications in Mathematical Physics 1 Journal d’Analyse Mathématique 1 Linear and Multilinear Algebra 1 Reviews of Modern Physics 1 Bulletin of Mathematical Biology 1 Reviews in Mathematical Physics 1 The Annals of Probability 1 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 1 Commentarii Mathematici Helvetici 1 Duke Mathematical Journal 1 Journal of the London Mathematical Society. Second Series 1 Journal of the Mathematical Society of Japan 1 Journal of Statistical Planning and Inference 1 Manuscripta Mathematica 1 Mathematische Zeitschrift 1 SIAM Journal on Algebraic and Discrete Methods 1 Bulletin of the Iranian Mathematical Society 1 Journal of Computer Science and Technology 1 Discrete & Computational Geometry 1 Journal of Cryptology 1 Science in China. Series A 1 Random Structures & Algorithms 1 Journal of Global Optimization 1 Expositiones Mathematicae 1 Mathematical Programming. Series A. Series B 1 Applicable Algebra in Engineering, Communication and Computing 1 Experimental Mathematics 1 Algebra Colloquium 1 St. Petersburg Mathematical Journal 1 Discussiones Mathematicae. Graph Theory 1 Bernoulli 1 Doklady Mathematics 1 Topoi 1 Algebras and Representation Theory 1 Acta Mathematica Sinica. English Series 1 Central European Journal of Mathematics 1 Quantum Information Processing ...and 15 more Serials
all top 5
#### Cited in 31 Fields
313 Group theory and generalizations (20-XX) 205 Combinatorics (05-XX) 95 Computer science (68-XX) 24 Nonassociative rings and algebras (17-XX) 19 Number theory (11-XX) 18 Information and communication theory, circuits (94-XX) 13 Operations research, mathematical programming (90-XX) 12 Probability theory and stochastic processes (60-XX) 10 Geometry (51-XX) 10 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 6 Algebraic geometry (14-XX) 6 Manifolds and cell complexes (57-XX) 6 Quantum theory (81-XX) 5 Associative rings and algebras (16-XX) 5 Convex and discrete geometry (52-XX) 4 Mathematical logic and foundations (03-XX) 3 General and overarching topics; collections (00-XX) 3 Order, lattices, ordered algebraic structures (06-XX) 3 Linear and multilinear algebra; matrix theory (15-XX) 3 Topological groups, Lie groups (22-XX) 2 History and biography (01-XX) 2 Commutative algebra (13-XX) 2 Category theory; homological algebra (18-XX) 2 $$K$$-theory (19-XX) 1 General algebraic systems (08-XX) 1 Field theory and polynomials (12-XX) 1 Functions of a complex variable (30-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Dynamical systems and ergodic theory (37-XX) 1 Biology and other natural sciences (92-XX) 1 Mathematics education (97-XX)
#### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-10-28T00:50:24 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7039956450462341, "perplexity": 10859.249991887576}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323588246.79/warc/CC-MAIN-20211028003812-20211028033812-00131.warc.gz"}
|
https://portlandpress.com/essaysbiochem/article/66/7/875/232132/The-biophysics-of-disordered-proteins-from-the
|
Intrinsically disordered proteins (IDPs) and regions (IDRs) have emerged as key players across many biological functions and diseases. Differently from structured proteins, disordered proteins lack stable structure and are particularly sensitive to changes in the surrounding environment. Investigation of disordered ensembles requires new approaches and concepts for quantifying conformations, dynamics, and interactions. Here, we provide a short description of the fundamental biophysical properties of disordered proteins as understood through the lens of single-molecule fluorescence observations. Single-molecule Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) provides an extensive and versatile toolbox for quantifying the characteristics of conformational distributions and the dynamics of disordered proteins across many different solution conditions, both in vitro and in living cells.
The last 20 years have seen the emergence of a class of proteins that challenge the classic structure–function paradigm [1]. Indeed, a large fraction of proteins in the eukaryotic proteome are completely or partially unstructured [2], but nevertheless play essential roles in biological function [3–6], ranging from transcription [7–10] and translation [11–13] to transport processes [14] and membrane organization [15–17]. Their ‘shape shifting’ nature upon binding [18] and the occurrence of short linear-interacting motifs [19,20] make them essential components of cellular signaling, allowing for specificity with a multiplicity of signaling targets [19–23]. The multivalence of interactions encoded in their sequence can also play an essential role in regulating self-assembly processes [3,24]. Because of these key roles, disordered proteins are also central to several diseases, such as neurodegeneration and cancer [25,26].
There is a whole spectrum of conformational heterogeneity in proteins, where disorder can span either the whole protein, some regions of the protein (e.g. tails and linkers that flank and connect folded domains), or just short loops that are involved in the organization of structured proteins. The environment ‘complexity’ can further modulate the properties of disordered proteins, since conformations and dynamics will depend on whether proteins are studied in isolation, in presence of ligands, or within the crowded milieu of a cell (Figure 1).
### Spectrum of conformational disorder
Figure 1
Spectrum of conformational disorder
A whole spectrum of disorder can occur in proteins, from completely unstructured sequences to disordered linkers and tails flanking folded domains or just short loops that introduce local disorder in mostly folded proteins. In addition, given the lack of a stable 3D structure, the complexity of the solution (in vitro and in the cell) can modulate conformations and dynamics of the disordered protein, whether the protein is studied in isolation, bound to a ligand, within a biomolecular condensate or other crowded environment.
Figure 1
Spectrum of conformational disorder
A whole spectrum of disorder can occur in proteins, from completely unstructured sequences to disordered linkers and tails flanking folded domains or just short loops that introduce local disorder in mostly folded proteins. In addition, given the lack of a stable 3D structure, the complexity of the solution (in vitro and in the cell) can modulate conformations and dynamics of the disordered protein, whether the protein is studied in isolation, bound to a ligand, within a biomolecular condensate or other crowded environment.
Close modal
These intrinsically disordered proteins (IDPs) and regions (IDRs) do not adopt a unique stable structure, but instead sample many different conformations. As a result, their flexible nature cannot be interpreted in the terms of classical structural biology and requires a different language to describe the properties of these conformational ensembles. At the same time, different experimental approaches are required to access and quantify protein conformations, dynamics, and interactions.
The physics of polymers has emerged as a powerful framework to identify key observables and explain the thermodynamic-driving forces controlling IDPs [27–30]. In parallel, single-molecule fluorescence spectroscopy has provided means to directly test and quantify predictions of polymer models. In this review, we have focused on recounting the major findings of the biophysics of disordered proteins in a simple and accessible form, discussing how single-molecule fluorescence spectroscopy can be harnessed to access such properties. We hope this brief summary can provide an entry point in the investigation of IDPs biophysics with single-molecule tools.
Single-molecule fluorescence spectroscopy offers a versatile toolbox to investigate the conformations and dynamics of disordered proteins across many solution conditions (Figures 2 and 3). The major advantages of single-molecule methods compared with classical ensemble approaches are: (i) the possibility of resolving distinct conformational ensembles, allowing for distinguishing structural conformational changes occurring with solvent conditions or upon binding with ligands; (ii) the ability of accessing protein dynamics contextually with information on the conformational ensemble; (iii) the particularly low concentration regime (picomolar range), which enables access to the monomeric form of the protein, even for aggregation and oligomerization prone sequences.
### Single-molecule fluorescence spectroscopy
Figure 2
Single-molecule fluorescence spectroscopy
(A) In Förster resonance energy transfer (FRET), donor excitation can either result in a photon emission from the donor itself or a nonradiative energy transfer to the acceptor with consequent emission of an acceptor photon without a direct excitation of the acceptor. (B) The efficiency of the energy transfer process depends on the interdye distance r to the power of 6 and on the characteristic Förster radius, which corresponds to the distance at which the efficiency is equal to 50% (compare with eqn 1). (C) In fluorescence correlation spectroscopy (FCS), the amplitude of the correlation reports about the inverse of the number of molecules N in the observation volume, whereas the shift in decay represents the characteristic time of decorrelation. In typical confocal experiments of freely diffusing molecules, one of the sources of decorrelation is the diffusion of the molecule in and out of the confocal volume and the characteristic time is the diffusion time τD (compare with eqns 5 and 6). (D) Other timescales that can be studied in FCS experiments are related to the excitation of the fluorophore (antibunching), the rotational diffusion of the molecule and intrachain dynamics, and the photophysics of the triplet state.
Figure 2
Single-molecule fluorescence spectroscopy
(A) In Förster resonance energy transfer (FRET), donor excitation can either result in a photon emission from the donor itself or a nonradiative energy transfer to the acceptor with consequent emission of an acceptor photon without a direct excitation of the acceptor. (B) The efficiency of the energy transfer process depends on the interdye distance r to the power of 6 and on the characteristic Förster radius, which corresponds to the distance at which the efficiency is equal to 50% (compare with eqn 1). (C) In fluorescence correlation spectroscopy (FCS), the amplitude of the correlation reports about the inverse of the number of molecules N in the observation volume, whereas the shift in decay represents the characteristic time of decorrelation. In typical confocal experiments of freely diffusing molecules, one of the sources of decorrelation is the diffusion of the molecule in and out of the confocal volume and the characteristic time is the diffusion time τD (compare with eqns 5 and 6). (D) Other timescales that can be studied in FCS experiments are related to the excitation of the fluorophore (antibunching), the rotational diffusion of the molecule and intrachain dynamics, and the photophysics of the triplet state.
Close modal
### Experimental methods for the study of disordered proteins
Figure 3
Experimental methods for the study of disordered proteins
Figure 3
Experimental methods for the study of disordered proteins
Close modal
The two major single-molecule fluorescence approaches that are commonly applied to IDPs rely on FRET and FCS.
FRET provides a molecular spectroscopic ruler to measure distances on the length scale of nanometers [31]. FRET experiments involve the attachment of two fluorophores to the protein of interest and require that the emission spectra of one fluorophore (the donor) overlaps with the absorption spectrum of the other fluorophore (the acceptor). When this condition is satisfied, the excitation of the donor fluorophore can lead to the direct emission of a donor photon or to a nonradiative energy transfer toward the acceptor and the consequent emission of an acceptor photon (Figure 2A). The efficiency of this energy transfer is given by (eqn 1):
$E(r)=R06R06+r6$
(1)
where r is the distance between the donor and the acceptor fluorophore and R0 is the Förster radius. The Förster radius sets the distance at which the transfer efficiency is equal to 50% and depends on the spectroscopic properties of the dyes, their reciprocal orientation, and the refractive index of the solution (Figure 2B).
Single-molecule detection is achieved by limiting the number of molecules in the volume of observation. This can be directly realized by sparsely immobilizing molecules on the surface, such that the molecules are statistically sufficiently separated from each other, or by studying freely diffusing molecules and diluting the sample such that statistically only one molecule is observed at a time. Typical experiments make use of either total internal reflection fluorescence (TIRF) or confocal microscope setups.
In TIRF experiments, the total internal reflection enables a thin layer of the solution (<100 nm from the coverslip) to be illuminated by an evanescent wave and the detection of excited fluorescent molecules is performed via a camera-based setup. The illumination of a small layer of solution allows studying interactions in presence of a high concentration of fluorescence proteins (e.g. ligands), since only the molecules close to the surface will be excited; however, it requires close proximity (normally, immobilization) of the sample to the surface. The camera-based setup enables the simultaneous detection of multiple molecules, though time resolution of fast events is limited by the camera frame rate (commonly in the tens of milliseconds timescale).
In single-molecule confocal setups, a laser beam is coupled into a microscope objective with a high numerical aperture, which focuses the beam into a diffraction-limited spot within the sample. Emitted photons are detected through the same objective, filtered through a small pinhole (between 30 and 150 nm), and finally separated and detected on single-photon avalanche photodiodes [32]. This type of setup is often coupled with fast electronics for single photon detection, allowing for molecules and fluorophore photophysics to be studied over a broad range of timescales, from picoseconds to minutes [31]. Confocal microscopy allows for both studying freely diffusing and immobilized molecules. However, for immobilized molecules, it requires focusing on each single molecule individually, making the acquisition time for multiple immobilized molecules significantly longer compared with the one obtained by TIRF microscopy; on the positive side, this approach commonly allows for much higher time resolution on the fast timescales, enabling access to fluorescence lifetimes and anisotropy.
In both TIRF and confocal single-molecule FRET, the transfer efficiency E is quantified by counting the number of donor and acceptor photons, nD and nA, according to (eqn 2):
$E=nA(nA+nD)$
(2)
If fluorescence lifetime is accessible, transfer efficiency can be also evaluated by comparing the lifetime of the donor in presence and in absence of the acceptor (eqn 3):
$E=1-τDAτD$
(3)
where τD is the fluorescence lifetime of the donor and τDA is the fluorescence lifetime of the donor in the presence of the acceptor.
FCS provides an alternative set of approaches to investigate protein conformations (the overall size) and dynamics. The concept of fluorescence correlation was originally introduced in the 1970s by Elson, Magde, and Webb [33–35] and relies on studying fluctuations in the intensity of fluorescence signals as a reporter for protein diffusion and concentration. This can be understood easily by considering a sufficiently dilute solution, where the passing of fluorescent molecules through the detection volume leads to significant changes in the detected intensity compared with the average background. This can be quantified by studying the correlation of the fluorescence fluctuations [36,37] (eqn 4):
$G(τ)=2$
(4)
where F(t) represents the fluorescence intensity at the time t, <> represents the temporal average over all times t, τ is the lag time at which the correlation G(τ) is computed. Under the assumption of a Gaussian 3D profile, the correlation can directly be linked to the diffusion time and concentration of molecules (eqn 5):
$GDiff(τ)=1N1+ττDiff-11+ττDiff.r02z02-0.5$
(5)
where N is equivalent to the average number of molecules in the detection volume, τDiff is the average time of molecules diffusing through the detection volume and r0 and z0 are the lateral and axial radial distances of the confocal volume, respectively (Figure 2C). While the amplitude of the correlation directly reports on the average number of molecules in the detection volume, τDiff reports about the diffusion coefficient of the molecule and can be related to its hydrodynamic Stokes-radius, RH (eqn 6):
(6)
where KB is the Boltzman constant, T is the absolute temperature, and η is the viscosity of the solution at a given T.
FCS measurements are commonly performed in a confocal setup and therefore are compatible with single-molecule FRET experiments. Indeed, FCS is not only limited to measure diffusion and concentration of molecules: depending on the source causing fluctuations in fluorescence intensity, FCS can provide access to static quenching and other photophysical properties of the dyes as well as dynamics within the molecule of interest (Figure 2D).
In 1999, the labs of DeGrado and Hochstrasser proved the feasibility of single-molecule FRET experiments on proteins, investigating the denaturation of immobilized [38] and freely diffusing [39] GCN-4 fragments. Contextually, Deniz et al. [40] demonstrated how this approach enables distinguishing and separating properties associated with the folded and unfolded states. Specifically, their measurements of the chymotrypsin inhibitor 2 identified changes of the unfolded state as a function of the denaturant, which the authors speculated could be due to loss of secondary structure or increase in solubility of the disordered state. Schuler et al. [41] observed analogous changes for the Cold shock protein of Thermotoga Maritima and, using polyproline sequences as control measurements, ruled out that the observations were due to photophysical effects, and indeed represented changes in the conformations of the unfolded state. These works set the stage for investigating the properties of the denatured state of foldable proteins, which represents another occurrence of ‘disorder’ in proteins.
In the case of denatured proteins, the mean transfer efficiency associated with the distribution of the unfolded state represents a mean value of the transfer efficiencies associated with the different configurations explored by the chain: because chain dynamics are significantly faster (nanosecond timescale) than the burst detection (millisecond) in single-molecule experiments, the different transfer efficiencies are averaged out [31]. The same applies to disordered proteins. The distance distribution associated with the denatured or disordered protein is often sufficiently well-described by simple polymer models (such as the Gaussian chain [42], Worm-like chain [43], and Self-Avoiding Walk distributions [29,44,45]), or can be estimated from simulations [28,46–48].
The work of Sherman and Haran [49] on the unfolded state of protein L introduced an important explanation for the conformational change of the disordered state when increasing denaturant, linking the observed phenomenon to the coil-to-globule transition in polymers [49–51]. Indeed, depending on the balance of the monomer–monomer and monomer–solvent interactions, polymers can adopt conformations of a compact globule (when monomer–monomer interactions dominate) or expanded conformations (when solvent–monomer interactions are favored) [42]. Varying the strength of monomer and solvent interactions leads to a transition between these two extreme cases and results in the so-called coil-to-globule transition [52]. Examples of interactions include excluded volume interactions (the physical occupancy of space of the residues), electrostatic interactions, and hydrophobic interactions. A particular case occurs when attractive and repulsive interactions in the system (protein and solvent) cancel each other: this particular condition is referred to as the ‘theta state’ or ‘theta solvent condition’ and is a key reference state in polymer physics. Altogether, the coil-to-globule framework provides a physical explanation for the change in conformations of the unfolded (either denatured or intrinsically disordered) state in presence of denaturant, where the denaturant acts as a better solvent and favors more expanded conformations.
This hypothesis has been further tested by Hofmann et al. [53]. Here, they harnessed the ability of measuring interdye distances within a protein by attaching fluorophores at different positions. This approach allows directly estimating the scaling exponent [54] of the disordered state under different solvent conditions, for both folded and IDPs. The scaling exponent relates the root-mean-square interdye distance <r2>0.5 to the degree of polymerization of the molecule (in this case, the number of peptide bonds in the protein) and is directly related to the three fundamental states identified in the coil-to-globule transition. <r2>0.5 is proportional to N1/3 for the case of a globule, to N1/2 for the case of an ideal chain, and to N0.588 for the case of a chain dominated by excluded volume effects. Hofmann et al. [53] found that in high denaturant different sequences follow the scaling exponent expected for a chain in a good solvent, whereas under native conditions different scaling exponents are observed depending on the sequence properties (charge, hydrophobicity, etc.) (Figure 4A). This observation was consistent with predictions from simulations [55,56] and with previous estimates of the scaling exponent of folded proteins in denaturant [57] and has been further corroborated in subsequent works exploring the role of denaturant on unfolded proteins [58–60]. FRET measurements have been also compared with FCS measurements and dynamic light scattering to confirm the expansion of the disordered state of proteins with increasing denaturant concentration [49,53,61,62].
### Examples of single-molecule fluorescence measurements
Figure 4
Examples of single-molecule fluorescence measurements
Figure 4
Examples of single-molecule fluorescence measurements
Close modal
The information from single-molecule FRET is often integrated with that provided by other approaches, which can help in defining the properties of the disordered ensemble. This includes measurements of the radius of gyration via SAXS [45,59,61,63–67], local conformations via NMR [65–68], and simulations [28,46–48,63,65,67,69].
The large spectrum of scaling exponents observed under native conditions for different unfolded and disordered proteins [53,64,70,71] reflects the contribution of sequence composition on the conformations of disordered ensembles. Müller-Späth et al. [72] used single-molecule FRET to probe the conformations of unfolded proteins, showing the degree of compaction and expansion of the interdye distance depends on the charged residue content in the protein, in good agreement with prediction from polymer theories [73–75]. Indeed, the theory of polyelectrolytes (polymers whose monomers carry all the same type of charge) and polyampholytes (polymers carrying both positive and negative charges) indicate that the dimension of charged polymers depends on the contribution of the total net charge of the protein (which favors the expansion of the chain) and the total number of charged residues of the chain (which represents local compaction along the chain due to the positive and negative residues in the chain). These observations matched independent computational work from the Pappu group [76], which further demonstrated how the net charge, total number of charged residues, and charge patterning can modulate the conformations of IDRs, favoring extended, compact, and more exotic conformations such as tadpoles and hairpins [77]. Advanced polymer models have been further developed to capture sequence-specific effects of charge distribution [78–80], revealing how the pattern of charges in polyampholyte sequences can even lead to coexistence of two distinct ensembles of conformations [81,82]. Importantly, parameters such as net charge and total charge are influenced by the ionization of charged groups, which may be affected by the local density of charged residues [83]. Polyampholyte and polyelectrolyte theories capture also the conformational response to salt, including effects of charge screening and counterion condensation [73,75,80,84,85].
While charged residues are an important determinant of IDPs/IDRs conformations, other amino acids can play a fundamental role on protein conformations [29]. For example, a comparative analysis of the hydrodynamic radii of different IDPs identified the content in proline residues as an essential factor modulating the disordered conformational ensemble [86]. SAXS measurements and simulations of Ash1 further revealed that proline residues can favor expanded configurations even when the charge content of the protein is changed by phosphorylation and more compacted conformations are expected to be populated [87]. Understanding the effect of sequence composition is essential to rationalize the conformational response to solution conditions and how this impacts the interaction with ligands. This is particularly important in the case of linkers, where sequence composition can modulate the local effective concentration of interacting regions [88,89].
Temperature modulation provides a wealth of information regarding the entropic and enthalpic contributions controlling molecular conformations and interactions [90]. This is often realized using custom built temperature-controlled chambers, where the sample temperature can be directly controlled and calibrated against a well-known standard (e.g. the temperature-dependent lifetime of rhodamine B) [90–92].
Single-molecule FRET experiments on IDRs and unfolded proteins as a function of temperature [91,93] have revealed a surprising result for the temperature dependence of chain dimensions. With increasing temperature, the disordered state conformations first undergo compaction before starting to expand again (Figure 4B). Similar results have been reported also for different IDPs by dynamic light scattering [94] and small angle X-ray [95,96] measurements. At first glance, these observations appear counterintuitive. Based on the classical dependence of the coil-to-globule observed in polymers [52], one would expect that a temperature increase would result in an expansion of the chain due to decrease in the strength of the interactions at play. The strengthening of interactions with increasing temperature points to a contribution of the ‘hydrophobic effect,’ but the extent of collapse is found to be amplified for hydrophilic charged sequences, not hydrophobic ones [93]. These observations can be rationalized by accounting for the temperature-dependent solvation free energies of the sequence amino acids [93]. The same temperature-induced collapse occurs when studying the unfolded state upon hot and cold denaturation [97,98], showing that the cold-denatured and hot-denatured state of a protein represents the same denatured state and their response to temperature follows the temperature trend of solvation-free energies [98].
While FRET is often used to determine conformational changes, it can also be used to investigate chain dynamics. Fast dynamics can be accessed by studying the autocorrelation of the donor and acceptor photons or the cross-correlation of donor and acceptor [99,100]. Use of zero-mode waveguides can shorten the acquisition time (down to tens of minutes) and enable measurements of very fast dynamics (low-nanoseconds) [101]. When studying fast dynamics with FCS, the correlation function in (eqn 5) (extends to (eqns 7a and 7b):
$G(τ)=1-cabi,jττabi,j1+cCDi,jττCD1+cTi,jττTi,jGDiff(τ),i=j$
(7a)
$G(τ)=1-cabi,jττabi,j1-cCDi,jττCD1+cTi,jττTi,jGDiff(τ),i≠j$
(7b)
where i and j identify either the donor or acceptor photon emission, $cabi,j$ and $τabi,j$ represent the amplitude and relaxation time of the antibunching component, $cTi,j$ and $τTi,j$ capture the contribution in amplitude and relaxation time of the triplet state, and and τCD reports about the amplitude and relaxation time of chain dynamics. Note that the relaxation timescale τCD is the same across all correlations, whereas the sign associated with the chain dynamics amplitude $cCDi,j$ depends on whether this is is an autocorrelation (i = j) or a cross-correlation (i ≠ j). The reason for change of sign in the cross-correlation is intuitively understood by considering that FRET, as measured by comparing donor and acceptor emission, is inherently anticorrelated: an increase in the acceptor emission comes at the cost of a decrease in donor signal and vice versa (see Figure 4D).
This approach has enabled quantifying the timescale at which disordered proteins sample the distribution associated with their conformational ensemble, which is often in the order of tens or hundreds of nanoseconds. The measured quantity is the reconfiguration time, which is the time that it takes to the specific interdye distance to lose memory of the previous configuration. Chain dynamics are consistent with the expected behavior of simple polymer models [102–104], where the overall reconfiguration time of the chain is given by the sum of two contributions, one dependent on the solvent and therefore on viscosity, and one independent of the solvent and is usually referred to as internal friction. Internal friction may arise from different molecular sources, including dihedral angle rotation [105–107] and transient contact formation [108]. ns-FRET FCS provides an effective tool to quantify solvent and internal friction contributions. One method relies on studying the viscosity dependence of the reconfiguration time titrating a viscogen that slows down the dynamics of the chain: a linear extrapolation to zero viscosity provides a value that reports on internal friction contributions. Alternatively, chain dynamics across different segment lengths of the disordered region can provide access to the same quantities: in this case, internal friction causes deviations from the behavior of ideal chain, where the reconfiguration is expected to scale with the length of the segment [104]. Comparison with all-atom simulations [109], NMR [66,110], and Neutron Scattering [111,112] experiments supports this model and the importance of internal friction effects.
Photo-induced electron transfer (PET) FCS provides a complementary point of view [109,113–115]. Here, the autocorrelation decay reports about quenching of the fluorophore due to static contact formation with quenching residues (tryptophan, tyrosine, and histidines) or synthetic moieties. In this case, the rates of forming and breaking the static complex, kon and koff, define the amplitude cCD = koff/kon and the relaxation time τCD = 1/(koff/kon) associated with chain dynamics (eqn 7a). Since the contact formation time measures the time required for two specific residues to come into contact, this time is usually longer than the reconfiguration time and the same polymer models mentioned above can be used to connect the two quantities. As expected based on the polymer models [103], contact formation is also impacted by internal friction [109].
While in the majority of cases, both FRET- and PET-FCS detect dynamics on the nanosecond time scale, this approach can indeed identify dynamics up to the diffusion time of the molecule (or longer, for immobilized molecules). Analysis of dynamics in the microsecond timescale can also be achieved by using BVA, which studies how the variance of transfer efficiency varies along the burst duration [116], or Hidden Markov analysis of the photon trajectory [117,118].
Single-molecule fluorescence spectroscopy can provide a direct readout for the interaction between disordered proteins and their ligands, whether these are small solutes (e.g. ions), another protein, or nucleic acids. Importantly, FRET enables the contextual study of conformations and dynamics, allowing discerning whether the interaction leads to folding upon binding [119–122] (Figure 4C), diffusion of the disordered protein on the folded-binding partner [123], or formation of a dynamic complex in which both components remain disordered (as in the case of prothymosin alpha and histone H1 [124,125] (Figure 4D)). Study of surface-tethered molecules enables quantification of the on- and off-rates of association via the analysis of the dwelling times in the bound and unbound state [120,126], as well as of transition path times [121,127] (Figure 4E). Alternatives for studying kinetics of interactions are offered by microfluidic mixing and recurrence analysis [128]. Microfluidic mixing provides common deadtimes of ∼1 ms, comparable with classic stop flow experiments [129–131]. Recurrence analysis relies on extremely dilute solutions, so dilute that there is a significant probability in short times to see the same molecule coming back (‘reoccurring’) in the confocal volume more than observing a new molecule [128]. This provides a direct tool to identify subpopulations in broad distribution histograms [123].
The single-molecule fluorescence toolbox is constantly growing and advancements in the last decade have demonstrated the feasibility and relevance of investigating IDPs in a complex environment. Indeed, the lack of a stable 3D structure makes disordered proteins prone to changes due to the surrounding milieu. We have already discussed how salt, temperature, and interactions with other molecules can alter IDPs conformations and dynamics. This becomes even more relevant in the context of the intracellular medium. Indeed, the cell milieu is occupied by a significant fraction of components (proteins, nucleic acids, metabolites), which is sufficiently high to limit the available volume that each component can explore. This phenomenon is commonly referred to as crowding and impacts many aspects of proteins and nucleic acids, including folding, dynamics, interactions, and in the case of disordered proteins, also their conformations. Recent applications on both proteins [132,133] and nucleic acids [134,135] have now highlighted the advantages of single-molecule fluorescence spectroscopy in quantifying such contributions on a molecule of interest. Indeed, single-molecule FRET can provide a direct readout for the conformational and kinetic changes within crowded solutions [132,133] as well as probe the possibility of inducing ‘folded’ conformations in equilibrium with the disordered state [132]. One important finding is that disordered proteins sense crowding differently depending on their degree of expansion [133]: IDRs that are more expanded are more sensitive to changes in the crowded solution. This can be quantified and rationalized in terms of their scaling exponent. IDRs with a scaling exponent larger than 0.5 will collapse with increasing concentration of crowding agents, whereas IDRs with a scaling exponent equal or smaller than 0.5 will have less or negligible impact of the crowded milieu, as expected based on the theory of polymer mixtures [136]. A discussion of the polymer and colloidal theories that applies to crowding are reported in [71]. The trend observed in vitro with polymeric crowded solutions is also observed in cells, where the same proteins undergoes compaction when decreasing the available volume in the cell, e.g. by inducing osmotic stress [137]. The emerging role of membrane-less compartments in the cellular environment has pushed to investigate the driving forces controlling their assembly. In particular, IDRs have been largely investigated in the context of biomolecular condensates. Recent experiments have showcased the possibility of using: (i) FCS to determine concentrations and dynamics inside the dilute and dense phase of condensates [138–142]; (ii) single-molecule FRET to quantify the conformational changes of disordered proteins within the dense phase [143,144]. (Figure 4F,G)
• Single-molecule fluorescence spectroscopy provides a versatile toolbox to investigate the biophysical properties of disordered proteins in isolation, when bound to another macromolecule, or within crowded environments.
• Measuring interdye distances via FRET enables studying contribution of the sequence composition and temperature effects on the dimensions of the disordered ensemble, providing direct access to physical parameters such as the scaling exponent.
• Nanosecond FRET- and PET-FCS provides access to fast chain dynamics and enables resolving solvent and internal friction contributions, whereas FCS captures conformational changes of the whole protein in terms of hydrodynamic radius.
• Integration of single-molecule fluorescence with orthogonal techniques such as SAXS, NMR, DLS, Neutron scattering, and simulations provides further constraints to capture the complexity of conformational ensembles along different length- and time-scales.
• Advancements in single-molecule spectroscopy and the growing understanding of the physical principles regulating disordered proteins pave the way to applying these methodologies to quantitatively understand the mechanisms of function and dysfunction.
The authors declare that there are no competing interests associated with the manuscript.
This work was supported by the NIH National Institute on Aging (Soranno, [grant number R01AG062837 (to J.C., M.D.S.B., and A.S.)]) and NIH National Institute on Allergic and Infectious Diseases (Soranno, [grant number R01AI163142 (to J.C., M.D.S.B., and A.S.)]).
J.C., M.D.S.B., and A.S. wrote the manuscript.
The authors thank Alessandro Borgia, Hagen Hofmann, Alex Holehouse, Dmitrii Makarov, Tanja Mittag, Daniel Nettels, Rohit Pappu, and Ben Schuler, for many stimulating discussions over the years on the topics of single-molecule spectroscopy and intrinsically disordered proteins.
BVA
burst variance analysis
DLS
dynamic light scattering
FCS
fluorescence correlation spectroscopy
FRET
Förster resonance energy transfer
IDP
intrinsically disordered protein
IDR
intrinsically disordered region
NMR
nuclear magnetic resonance
PET
photo-induced electron transfer
SAXS
small angle x-ray scattering
TIRF
total internal reflection fluorescence
1.
Wright
P.E.
and
Dyson
H.J.
(
1999
)
Intrinsically unstructured proteins: re-assessing the protein structure-function paradigm
.
J. Mol. Biol.
293
,
321
331
[PubMed]
2.
Wright
P.E.
and
Dyson
H.J.
(
2015
)
Intrinsically disordered proteins in cellular signalling and regulation
.
Nat. Rev. Mol. Cell Biol.
16
,
18
29
[PubMed]
3.
Dunker
A.K.
,
Keith Dunker
A.
,
Brown
C.J.
,
David Lawson
J.
,
Iakoucheva
L.M.
and
Z.
(
2002
)
Intrinsic disorder and protein function
.
Biochemistry
41
,
6573
6582
[PubMed]
4.
Uversky
V.N.
(
2002
)
Natively unfolded proteins: a point where biology waits for physics
.
Protein Sci.
11
,
739
756
[PubMed]
5.
Habchi
J.
,
Tompa
P.
,
Longhi
S.
and
Uversky
V.N.
(
2014
)
Introducing protein intrinsic disorder
.
Chem. Rev.
114
,
6561
6588
[PubMed]
6.
van der Lee
R.
,
Buljan
M.
,
Lang
B.
,
Weatheritt
R.J.
,
Daughdrill
G.W.
,
Dunker
A.K.
et al.
(
2014
)
Classification of intrinsically disordered regions and proteins
.
Chem. Rev.
114
,
6589
6631
[PubMed]
7.
Tsafou
K.
,
Tiwari
P.B.
,
Forman-Kay
J.D.
,
Metallo
S.J.
and
Toretsky
J.A.
(
2018
)
Targeting intrinsically disordered transcription factors: changing the paradigm
.
J. Mol. Biol.
430
,
2321
2341
[PubMed]
8.
Staby
L.
,
O'Shea
C.
,
Willemoës
M.
,
Theisen
F.
,
Kragelund
B.B.
and
Skriver
K.
(
2017
)
Eukaryotic transcription factors: paradigms of protein intrinsic disorder
.
Biochem. J.
474
,
2509
2532
[PubMed]
9.
Frege
T.
and
Uversky
V.N.
(
2015
)
Intrinsically disordered proteins in the nucleus of human cells
.
Biochem. Biophys. Rep.
1
,
33
51
[PubMed]
10.
Liu
J.
,
Perumal
N.B.
,
Oldfield
C.J.
,
Su
E.W.
,
Uversky
V.N.
and
Dunker
A.K.
(
2006
)
Intrinsic disorder in transcription factors
.
Biochemistry
45
,
6873
6888
[PubMed]
11.
Lee
C.Y.S.
,
Putnam
A.
,
Lu
T.
,
He
S.
,
Ouyang
J.P.T.
and
Seydoux
G.
(
2020
)
Recruitment of mRNAs to P granules by condensation with intrinsically-disordered proteins
.
Elife
9
,
12.
Hershey
P.E.
,
McWhirter
S.M.
,
Gross
J.D.
,
Wagner
G.
,
Alber
T.
and
Sachs
A.B.
(
1999
)
The Cap-binding protein eIF4E promotes folding of a functional domain of yeast translation initiation factor eIF4G1
.
J. Biol. Chem.
274
,
21297
21304
[PubMed]
13.
Fletcher
C.M.
,
McGuire
A.M.
,
Gingras
A.C.
,
Li
H.
,
Matsuo
H.
,
Sonenberg
N.
et al.
(
1998
)
4E binding proteins inhibit the translation factor eIF4E without folded structure
.
Biochemistry
37
,
9
15
[PubMed]
14.
Lemke
E.A.
(
2016
)
The multiple faces of disordered nucleoporins
.
J. Mol. Biol.
428
,
2011
2024
[PubMed]
15.
Busch
D.J.
,
Houser
J.R.
,
Hayden
C.C.
,
Sherman
M.B.
,
Lafer
E.M.
and
Stachowiak
J.C.
(
2015
)
Intrinsically disordered proteins drive membrane curvature
.
Nat. Commun.
6
,
7875
[PubMed]
16.
Zeno
W.F.
,
Baul
U.
,
W.T.
,
DeGroot
A.C.M.
,
Wang
L.
,
Lafer
E.M.
et al.
(
2018
)
Synergy between intrinsically disordered domains and structured proteins amplifies membrane curvature sensing
.
Nat. Commun.
9
,
4152
[PubMed]
17.
Fiebig
K.M.
,
Rice
L.M.
,
Pollock
E.
and
Brunger
A.T.
(
1999
)
Folding intermediates of SNARE complex assembly
.
Nat. Struct. Biol.
6
,
117
123
[PubMed]
18.
Robustelli
P.
,
Piana
S.
and
Shaw
D.E.
(
2020
)
Mechanism of coupled folding-upon-binding of an intrinsically disordered protein
.
J. Am. Chem. Soc.
142
,
11092
11101
[PubMed]
19.
Barbar
E.J.
and
Jespersen
N.
(
2020
)
Emerging features of linear motif-binding hub proteins
.
Biophysical J.
118
,
341a
20.
Berlow
R.B.
,
Dyson
H.J.
and
Wright
P.E.
(
2022
)
Multivalency enables unidirectional switch-like competition between intrinsically disordered proteins
.
Proc. Natl. Acad. Sci. U.S.A.
119
,
[PubMed]
21.
Bugge
K.
,
Staby
L.
,
E.
,
Falbe-Hansen
R.G.
,
Kragelund
B.B.
and
Skriver
K.
(
2021
)
αα-Hub domains and intrinsically disordered proteins: a decisive combo
.
J. Biol. Chem.
296
,
100226
[PubMed]
22.
Bondos
S.E.
,
Dunker
A.K.
and
Uversky
V.N.
(
2022
)
Intrinsically disordered proteins play diverse roles in cell signaling
.
Cell Commun. Signal.
20
,
20
[PubMed]
23.
Kim
P.M.
,
Sboner
A.
,
Xia
Y.
and
Gerstein
M.
(
2008
)
The role of disorder in interaction networks: a structural analysis
.
Mol. Syst. Biol.
4
,
179
[PubMed]
24.
Simon
J.R.
,
Carroll
N.J.
,
Rubinstein
M.
,
Chilkoti
A.
and
López
G.P.
(
2017
)
Programming molecular self-assembly of intrinsically disordered proteins containing sequences of low complexity
.
Nat. Chem.
9
,
509
515
[PubMed]
25.
Uversky
V.N.
,
Oldfield
C.J.
and
Dunker
A.K.
(
2008
)
Intrinsically disordered proteins in human diseases: introducing the D2 concept
.
Annu. Rev. Biophys.
37
,
215
246
[PubMed]
26.
Babu
M.M.
(
2016
)
The contribution of intrinsically disordered regions to protein function, cellular complexity, and human disease
.
Biochem. Soc. Trans.
44
,
1185
1200
[PubMed]
27.
Schuler
B.
,
Soranno
A.
,
Hofmann
H.
and
Nettels
D.
(
2016
)
Single-molecule FRET spectroscopy and the polymer physics of unfolded and intrinsically disordered proteins
.
Annu. Rev. Biophys.
45
,
207
231
[PubMed]
28.
Best
R.B.
(
2017
)
Computational and theoretical advances in studies of intrinsically disordered proteins
.
Curr. Opin. Struct. Biol.
42
,
147
154
[PubMed]
29.
Soranno
A.
(
2020
)
Physical basis of the disorder-order transition
.
Arch. Biochem. Biophys.
685
,
108305
[PubMed]
30.
Holehouse
A.S.
and
Pappu
R.V.
(
2018
)
Collapse transitions of proteins and the interplay among backbone, sidechain, and solvent interactions
.
Annu. Rev. Biophys.
47
,
19
39
[PubMed]
31.
Schuler
B.
(
2013
)
Single-molecule FRET of protein structure and dynamics - a primer
.
J. Nanobiotechnol.
11
,
S2
[PubMed]
32.
Böhmer
M.
and
Enderlein
J.
(
2003
)
Fluorescence spectroscopy of single molecules under ambient conditions: methodology and technology
.
ChemPhysChem
4
,
793
808
[PubMed]
33.
Elson
E.L.
and
Magde
D.
(
1974
)
Fluorescence correlation spectroscopy. I. Conceptual basis and theory
.
Biopolymers
,
13
,
1
,
1
27
34.
Magde
D.
,
Elson
E.
and
Webb
W.W.
Thermodynamic fluctuations in a reacting system-measurement by fluorescence correlation spectroscopy
.
Phys. Rev. Lett.
,
29
,
705
35.
Magde
D.
,
Elson
E.L.
and
Webb
W.W.
(
1974
)
Fluorescence correlation spectroscopy. II. An experimental realization
.
Biopolymers
13
,
29
61
[PubMed]
36.
Sauer
M.
,
Hofkens
J.
and
Enderlein
J.
(
2010
)
Handbook of Fluorescence Spectroscopy and Imaging: From Ensemble to Single Molecules
, p.
290
,
John Wiley & Sons
,
New Jersey, USA
37.
Rigler
R.
and
Elson
E.
(
2001
)
Fluorescence Correlation Spectroscopy
,
Springer
,
New York/Berlin
38.
Jia
Y.
,
Talaga
D.S.
,
Lau
W.L.
,
Lu
H.S.M.
,
W.F.
and
Hochstrasser
R.M.
(
1999
)
Folding dynamics of single GCN-4 peptides by fluorescence resonant energy transfer confocal microscopy
.
Chem. Phys.
247
,
69
83
39.
Talaga
D.S.
,
Lau
W.L.
,
Roder
H.
,
Tang
J.
,
Jia
Y.
,
W.F.
et al.
(
2000
)
Dynamics and folding of single two-stranded coiled-coil peptides studied by fluorescent energy transfer confocal microscopy
.
Proc. Natl. Acad. Sci. U.S.A.
97
,
13021
13026
[PubMed]
40.
Deniz
A.A.
,
Laurence
T.A.
,
Beligere
G.S.
,
Dahan
M.
,
Martin
A.B.
,
Chemla
D.S.
et al.
(
2000
)
Single-molecule protein folding: diffusion fluorescence resonance energy transfer studies of the denaturation of chymotrypsin inhibitor 2
.
Proc. Natl. Acad. Sci. U.S.A.
97
,
5179
5184
[PubMed]
41.
Schuler
B.
,
Lipman
E.A.
and
Eaton
W.A.
(
2002
)
Probing the free-energy surface for protein folding with single-molecule fluorescence spectroscopy
.
Nature
419
,
743
747
[PubMed]
42.
Rubinstein
M.
and
Colby
R.H.
(
2003
)
Polymer Physics
,
Oxford University Press
,
New York
43.
O'Brien
E.P.
,
Morrison
G.
,
Brooks
B.R.
and
Thirumalai
D.
(
2009
)
How accurate are polymer models in the analysis of Förster resonance energy transfer experiments on proteins?
J. Chem. Phys.
130
,
124903
[PubMed]
44.
McCarney
E.R.
,
Werner
J.H.
,
Bernstein
S.L.
,
Ruczinski
I.
,
Makarov
D.E.
,
Goodwin
P.M.
et al.
(
2005
)
Site-specific dimensions across a highly denatured protein; a single molecule study
.
J. Mol. Biol.
352
,
672
682
[PubMed]
45.
Zheng
W.
,
Zerze
G.H.
,
Borgia
A.
,
Mittal
J.
,
Schuler
B.
and
Best
R.B.
(
2018
)
Inferring properties of disordered chains from FRET transfer efficiencies
.
J. Chem. Phys.
148
,
123329
[PubMed]
46.
Shea
J.E.
,
Best
R.B.
and
Mittal
J.
(
2021
)
Physics-based computational and theoretical approaches to intrinsically disordered proteins
.
Current Opinion Struct. Biol.
67
,
219
225
47.
Alston
J.J.
,
Soranno
A.
and
Holehouse
A.S.
(
2021
)
Integrating single-molecule spectroscopy and simulations for the study of intrinsically disordered proteins
.
Methods
193
,
116
135
[PubMed]
48.
Ruff
K.M.
,
Pappu
R.V.
and
Holehouse
A.S.
(
2019
)
Conformational preferences and phase behavior of intrinsically disordered low complexity sequences: insights from multiscale simulations
.
Curr. Opin. Struct. Biol.
56
,
1
10
[PubMed]
49.
Sherman
E.
and
Haran
G.
(
2006
)
Coil-globule transition in the denatured state of a small protein
.
Proc. Natl. Acad. Sci. U.S.A.
103
,
11539
11543
[PubMed]
50.
Ziv
G.
,
Thirumalai
D.
and
Haran
G.
(
2009
)
Collapse transition in proteins
.
Phys. Chem. Chem. Phys.
11
,
83
93
[PubMed]
51.
Ziv
G.
and
Haran
G.
(
2009
)
Protein folding, protein collapse, and tanford's transfer model: lessons from single-molecule FRET
.
J. Am. Chem. Soc.
131
,
2942
2947
[PubMed]
52.
Sanchez
I.C.
(
1979
)
Phase transition behavior of the isolated polymer chain
.
Macromolecules
12
,
980
988
53.
Hofmann
H.
,
Soranno
A.
,
Borgia
A.
,
Gast
K.
,
Nettels
D.
and
Schuler
B.
(
2012
)
Polymer scaling laws of unfolded and intrinsically disordered proteins quantified with single-molecule spectroscopy
.
Proc. Natl. Acad. Sci. U.S.A.
109
,
16155
16160
[PubMed]
54.
de Gennes
P.G.
and
Gennes
P.G.
(
1979
)
Scaling Concepts in Polymer Physics
, p.
324
,
Cornell University Press
,
Ithaca, NY USA
55.
Tran
H.T.
and
Pappu
R.V.
(
2006
)
Toward an accurate theoretical framework for describing ensembles for proteins under strongly denaturing conditions
.
Biophys. J.
91
,
1868
1886
[PubMed]
56.
Meng
W.
,
Lyle
N.
,
Luan
B.
,
Raleigh
D.P.
and
Pappu
R.V.
(
2013
)
Experiments and simulations show how long-range contacts can form in expanded unfolded proteins with negligible secondary structure
.
Proc. Natl. Acad. Sci. U.S.A.
110
,
2123
2128
[PubMed]
57.
Kohn
J.E.
,
Millett
I.S.
,
Jacob
J.
,
Zagrovic
B.
,
Dillon
T.M.
,
Cingel
N.
et al.
(
2004
)
Random-coil behavior and the dimensions of chemically unfolded proteins
.
Proc. Natl. Acad. Sci. U.S.A.
101
,
12491
12496
58.
Holehouse
A.S.
,
Garai
K.
,
Lyle
N.
,
Vitalis
A.
and
Pappu
R.V.
(
2015
)
Quantitative assessments of the distinct contributions of polypeptide backbone amides versus side chain groups to chain expansion via chemical denaturation
.
J. Am. Chem. Soc.
137
,
2984
2995
[PubMed]
59.
Zheng
W.
,
Borgia
A.
,
Buholzer
K.
,
Grishaev
A.
,
Schuler
B.
and
Best
R.B.
(
2016
)
Probing the action of chemical denaturant on an intrinsically disordered protein by simulation and experiment
.
J. Am. Chem. Soc.
138
,
11702
11713
[PubMed]
60.
Peran
I.
,
Holehouse
A.S.
,
Carrico
I.S.
,
Pappu
R.V.
,
Bilsel
O.
and
Raleigh
D.P.
(
2019
)
Unfolded states under folding conditions accommodate sequence-specific conformational preferences with random coil-like dimensions
.
Proc. Natl. Acad. Sci. U.S.A.
116
,
12301
12310
[PubMed]
61.
Borgia
A.
,
Zheng
W.
,
Buholzer
K.
,
Borgia
M.B.
,
Schüler
A.
,
Hofmann
H.
et al.
(
2016
)
Consistent view of polypeptide chain expansion in chemical denaturants from multiple experimental methods
.
J. Am. Chem. Soc.
138
,
11714
11726
[PubMed]
62.
Chen
H.
and
E.
(
2008
)
Fluorescence characterization of denatured proteins
.
Curr. Opin. Struct. Biol.
18
,
516
524
[PubMed]
63.
Fuertes
G.
,
Banterle
N.
,
Ruff
K.M.
,
Chowdhury
A.
,
D.
,
Koehler
C.
et al.
(
2017
)
Decoupling of size and shape fluctuations in heteropolymeric sequences reconciles discrepancies in SAXS vs. FRET Measurements
.
Proc. Natl. Acad. Sci. U.S.A.
114
,
E6342
E6351
[PubMed]
64.
Riback
J.A.
,
Bowman
M.A.
,
Zmyslowski
A.M.
,
Plaxco
K.W.
,
Clark
P.L.
and
Sosnick
T.R.
(
2019
)
Commonly used FRET fluorophores promote collapse of an otherwise disordered protein
.
Proc. Natl. Acad. Sci. U.S.A.
116
,
8889
8894
[PubMed]
65.
Naudi-Fabra
S.
,
Tengo
M.
,
Jensen
M.R.
,
Blackledge
M.
and
Milles
S.
(
2021
)
Quantitative description of intrinsically disordered proteins using single-molecule FRET, NMR, and S.A.X.S
.
J. Am Chem Soc.
143
,
20109
20121
[PubMed]
66.
Aznauryan
M.
,
L.
,
Soranno
A.
,
Nettels
D.
,
Huang
J.R.
,
Labhardt
A.M.
et al.
(
2016
)
Comprehensive structural and dynamical view of an unfolded protein from the combination of single-molecule FRET, NMR, and SAXS
.
Proc. Natl. Acad. Sci. U.S.A.
113
,
E5389
E5398
[PubMed]
67.
Stelzl
L.S.
,
Pietrek
L.M.
,
Holla
A.
,
Oroz
J.
,
Sikora
M.
,
Köfinger
J.
et al.
(
2022
)
Global structure of the intrinsically disordered protein tau emerges from its local structure
.
JACS Au.
2
,
673
686
[PubMed]
68.
Gomes
G.N.W.
,
Krzeminski
M.
,
Namini
A.
,
Martin
E.W.
,
Mittag
T.
,
T.
et al.
(
2020
)
Conformational ensembles of an intrinsically disordered protein consistent with NMR, SAXS, and single-molecule FRET
.
J. Am. Chem. Soc.
142
,
15697
15710
[PubMed]
69.
Metskas
L.A.
and
E.
(
2015
)
Conformation and dynamics of the troponin I C-terminal domain: combining single-molecule and computational approaches for a disordered protein region
.
J. Am. Chem. Soc.
137
,
11962
11969
[PubMed]
70.
Best
R.B.
,
Zheng
W.
,
Borgia
A.
,
Buholzer
K.
,
Borgia
M.B.
,
Hofmann
H.
et al.
(
2018
)
Comment on “Innovative scattering analysis shows that hydrophobic disordered proteins are expanded in water”
.
Science
361
,
eaar7101
[PubMed]
71.
Cubuk
J.
and
Soranno
A.
(
2022
)
Macromolecular crowding and intrinsically disordered proteins: a polymer physics perspective
.
Chem. Systems Chem.
,
4
,
e202100051
72.
Müller-Späth
S.
,
Soranno
A.
,
Hirschfeld
V.
,
Hofmann
H.
,
Rüegger
S.
,
Reymond
L.
et al.
(
2010
)
Charge interactions can dominate the dimensions of intrinsically disordered proteins
.
Proc. Natl. Acad. Sci. U.S.A.
107
,
14609
14614
[PubMed]
73.
Ha
B.Y.
and
Thirumalai
D.
(
1995
)
Electrostatic persistence length of a polyelectrolyte chain
.
Macromolecules
28
,
577
581
74.
Ha
B.Y.
and
Thirumalai
D.
(
1992
)
Conformations of a polyelectrolyte chain
.
Phys. Rev. A.
46
,
R3012
R3015
[PubMed]
75.
Higgs
P.G.
and
Joanny
J.
(
1991
)
Theory of polyampholyte solutions
.
J. Chem. Phys.
94
,
1543
1554
76.
Mao
A.H.
,
Crick
S.L.
,
Vitalis
A.
,
Chicoine
C.L.
and
Pappu
R.V.
(
2010
)
Net charge per residue modulates conformational ensembles of intrinsically disordered proteins
.
Proc. Natl. Acad. Sci. U.S.A.
107
,
8183
8188
77.
Das
R.K.
and
Pappu
R.V.
(
2013
)
Conformations of intrinsically disordered proteins are influenced by linear sequence distributions of oppositely charged residues
.
Proc. Natl. Acad. Sci. U.S.A.
110
,
13392
13397
[PubMed]
78.
Sawle
L.
and
Ghosh
K.
(
2015
)
A theoretical method to compute sequence dependent configurational properties in charged polymers and proteins
.
J. Chem. Phys.
143
,
085101
[PubMed]
79.
Huihui
J.
and
Ghosh
K.
(
2020
)
An analytical theory to describe sequence-specific inter-residue distance profiles for polyampholytes and intrinsically disordered proteins
.
J. Chem. Phys.
152
,
161102
[PubMed]
80.
Samanta
H.S.
,
Chakraborty
D.
and
Thirumalai
D.
(
2018
)
Charge fluctuation effects on the shape of flexible polyampholytes with applications to intrinsically disordered proteins
.
J. Chem. Physics
149
,
163323
81.
Firman
T.
and
Ghosh
K.
(
2018
)
Sequence charge decoration dictates coil-globule transition in intrinsically disordered proteins
.
J. Chem. Phys.
148
,
123305
[PubMed]
82.
Zeng
X.
,
Ruff
K.M.
and
Pappu
R.V.
(
2022
)
Competing interactions give rise to two-state behavior and switch-like transitions in charge-rich intrinsically disordered proteins
.
Proc. Natl. Acad. Sci. U.S.A.
119
,
e2200559119
[PubMed]
83.
Fossat
M.J.
,
Posey
A.E.
and
Pappu
R.V.
(
2021
)
Quantifying charge state heterogeneity for proteins with multiple ionizable residues
.
Biophys. J.
120
,
5438
5453
[PubMed]
84.
Kundagrami
A.
and
Muthukumar
M.
(
2008
)
Theory of competitive counterion adsorption on flexible polyelectrolytes: divalent salts
.
J. Chem. Phys.
128
,
244901
[PubMed]
85.
Huihui
J.
,
Firman
T.
and
Ghosh
K.
(
2018
)
Modulating charge patterning and ionic strength as a strategy to induce conformational changes in intrinsically disordered proteins
.
J. Chem. Phys.
149
,
085101
[PubMed]
86.
Marsh
J.A.
and
Forman-Kay
J.D.
(
2010
)
Sequence determinants of compaction in intrinsically disordered proteins
.
Biophys. J.
98
,
2383
2390
[PubMed]
87.
Martin
E.W.
,
Holehouse
A.S.
,
Grace
C.R.
,
Hughes
A.
,
Pappu
R.V.
and
Mittag
T.
(
2016
)
Sequence determinants of the conformational properties of an intrinsically disordered protein prior to and upon multisite phosphorylation
.
J. Am. Chem. Soc.
138
,
15323
15335
[PubMed]
88.
Sørensen
C.S.
and
Kjaergaard
M.
(
2019
)
Effective concentrations enforced by intrinsically disordered linkers are governed by polymer physics
.
Proc. Natl. Acad. Sci. U.S.A.
116
,
23124
23131
[PubMed]
89.
Dyla
M.
,
González Foutel
N.S.
,
Otzen
D.E.
and
Kjaergaard
M.
(
2022
)
The optimal docking strength for reversibly tethered kinases
.
Proc. Natl. Acad. Sci. U.S.A.
119
,
e2203098119
[PubMed]
90.
Holmstrom
E.D.
and
Nesbitt
D.J.
(
2016
)
Biophysical insights from temperature-dependent single-molecule Förster resonance energy transfer
.
Annu. Rev. Phys. Chem.
67
,
441
465
[PubMed]
91.
Nettels
D.
,
Müller-Späth
S.
,
Küster
F.
,
Hofmann
H.
,
Haenni
D.
,
Rüegger
S.
et al.
(
2009
)
Single-molecule spectroscopy of the temperature-induced collapse of unfolded proteins
.
Proc. Natl. Acad. Sci. U.S.A.
106
,
20740
20745
[PubMed]
92.
Hartmann
A.
,
Berndt
F.
,
Ollmann
S.
,
Krainer
G.
and
Schlierf
M.
(
2018
)
In situ temperature monitoring in single-molecule FRET experiments
.
J. Chem. Phys.
148
,
123330
[PubMed]
93.
Wuttke
R.
,
Hofmann
H.
,
Nettels
D.
,
Borgia
M.B.
,
Mittal
J.
,
Best
R.B.
et al.
(
2014
)
Temperature-dependent solvation modulates the dimensions of disordered proteins
.
Proc. Natl. Acad. Sci. U.S.A.
111
,
5213
5218
[PubMed]
94.
Langridge
T.D.
,
Tarver
M.J.
and
Whitten
S.T.
(
2014
)
Temperature effects on the hydrodynamic radius of the intrinsically disordered N-terminal region of the p53 protein
.
Proteins
82
,
668
678
[PubMed]
95.
Battisti
A.
,
Ciasca
G.
,
Grottesi
A.
and
Tenenbaum
A.
(
2017
)
Thermal compaction of the intrinsically disordered protein tau: entropic, structural, and hydrophobic factors
.
Phys. Chem. Chem. Phys.
19
,
8435
8446
[PubMed]
96.
Stenzoski
N.E.
,
Luan
B.
,
Holehouse
A.S.
and
Raleigh
D.P.
(
2018
)
The unfolded state of the C-terminal domain of L9 expands at low but not at elevated temperatures
.
Biophys. J.
115
,
655
663
[PubMed]
97.
Stenzoski
N.E.
,
Zou
J.
,
Piserchio
A.
,
Ghose
R.
,
Holehouse
A.S.
and
Raleigh
D.P.
(
2020
)
The cold-unfolded state is expanded but contains long- and medium-range contacts and is poorly described by homopolymer models
.
Biochemistry
59
,
3290
3299
[PubMed]
98.
Aznauryan
M.
,
Nettels
D.
,
Holla
A.
,
Hofmann
H.
and
Schuler
B.
(
2013
)
Single-molecule spectroscopy of cold denaturation and the temperature-induced collapse of unfolded proteins
.
J. Am. Chem. Soc.
135
,
14040
14043
[PubMed]
99.
Nettels
D.
,
Gopich
I.V.
,
Hoffmann
A.
and
Schuler
B.
(
2007
)
Ultrafast dynamics of protein collapse from single-molecule photon statistics
.
Proc. Natl. Acad. Sci. U.S.A.
104
,
2655
2660
[PubMed]
100.
Gopich
I.V.
,
Nettels
D.
,
Schuler
B.
and
Szabo
A.
(
2009
)
Protein dynamics from single-molecule fluorescence intensity correlation functions
.
J. Chem. Phys.
131
,
095102
[PubMed]
101.
Nüesch
M.F.
,
Ivanović
M.T.
,
Claude
J.B.
,
Nettels
D.
,
Best
R.B.
,
Wenger
J.
et al.
(
2022
)
Single-molecule detection of ultrafast biomolecular dynamics with nanophotonics
.
J. Am. Chem. Soc.
144
,
52
56
[PubMed]
102.
Khatri
B.S.
and
McLeish
T.C.B.
(
2007
)
Rouse model with internal friction: a coarse grained framework for single biopolymer dynamics
.
Macromolecules
40
,
6770
6777
103.
Cheng
R.R.
,
Hawk
A.T.
and
Makarov
D.E.
(
2013
)
Exploring the role of internal friction in the dynamics of unfolded proteins using simple polymer models
.
J. Chem. Phys.
138
,
074112
[PubMed]
104.
Soranno
A.
,
Buchli
B.
,
Nettels
D.
,
Cheng
R.R.
,
Müller-Späth
S.
,
Pfeil
S.H.
et al.
(
2012
)
Quantifying internal friction in unfolded and intrinsically disordered proteins with single-molecule spectroscopy
.
Proc. Natl. Acad. Sci. U.S.A.
109
,
17800
17806
[PubMed]
105.
Echeverria
I.
,
Makarov
D.E.
and
Papoian
G.A.
(
2014
)
Concerted dihedral rotations give rise to internal friction in unfolded proteins
.
J. Am. Chem. Soc.
136
,
8708
8713
[PubMed]
106.
Soranno
A.
,
Zosel
F.
and
Hofmann
H.
(
2018
)
Internal friction in an intrinsically disordered protein-comparing Rouse-like models with experiments
.
J. Chem. Phys.
148
,
123326
[PubMed]
107.
Das
D.
,
Arora
L.
and
S.
(
2022
)
Short-range backbone dihedral rotations modulate internal friction in intrinsically disordered proteins
.
J. Am. Chem. Soc.
144
,
1739
1747
[PubMed]
108.
Barsegov
V.
,
Morrison
G.
and
Thirumalai
D.
(
2008
)
Role of internal chain dynamics on the rupture kinetic of adhesive contacts
.
Phys. Rev. Lett.
100
,
248102
[PubMed]
109.
Soranno
A.
,
Holla
A.
,
Dingfelder
F.
,
Nettels
D.
,
Makarov
D.E.
and
Schuler
B.
(
2017
)
Integrated view of internal friction in unfolded proteins from single-molecule FRET, contact quenching, theory, and simulations
.
Proc. Natl. Acad. Sci. U.S.A.
114
,
E1833
E1839
[PubMed]
110.
Rezaei‐Ghaleh
N.
,
Parigi
G.
,
Soranno
A.
,
Holla
A.
,
Becker
S.
,
Schuler
B.
et al.
(
2018
)
Local and global dynamics in intrinsically disordered synuclein
.
Angew. Chem. Int. Ed.
57
,
15262
15266
111.
Stingaciu
L.R.
,
Biehl
R.
,
Changwoo
D.
,
Richter
D.
and
A.M.
(
2020
)
Reduced internal friction by osmolyte interaction in intrinsically disordered myelin basic protein
.
J. Phys. Chem. Lett.
11
,
292
296
[PubMed]
112.
Ameseder
F.
,
A.
,
Holderer
O.
,
Falus
P.
,
Richter
D.
and
A.M.
(
2018
)
Relevance of internal friction and structural constraints for the dynamics of denatured bovine serum albumin
.
J. Phys. Chem. Lett.
9
,
2469
2473
[PubMed]
113.
Sauer
M.
and
Neuweiler
H.
(
2014
)
PET-FCS: probing rapid structural fluctuations of proteins and nucleic acids by single-molecule fluorescence quenching
.
Methods Mol. Biol.
1076
,
597
615
[PubMed]
114.
Vaiana
A.C.
,
Neuweiler
H.
,
Schulz
A.
,
Wolfrum
J.
,
Sauer
M.
and
Smith
J.C.
(
2003
)
Fluorescence quenching of dyes by tryptophan: interactions at atomic detail from combination of experiment and computer simulation
.
J. Am. Chem. Soc.
125
,
14564
14572
[PubMed]
115.
Zosel
F.
,
Haenni
D.
,
Soranno
A.
,
Nettels
D.
and
Schuler
B.
(
2017
)
Combining short- and long-range fluorescence reporters with simulations to explore the intramolecular dynamics of an intrinsically disordered protein
.
J. Chem. Phys.
147
,
152708
[PubMed]
116.
Torella
J.P.
,
Holden
S.J.
,
Santoso
Y.
,
Hohlbein
J.
and
Kapanidis
A.N.
(
2011
)
Identifying molecular dynamics in single-molecule FRET experiments with burst variance analysis
.
Biophys. J.
100
,
1568
1577
[PubMed]
117.
Harris
P.D.
,
Narducci
A.
,
Gebhardt
C.
,
Cordes
T.
,
Weiss
S.
and
Lerner
E.
(
2022
)
Multi-parameter photon-by-photon hidden Markov modeling
.
Nat. Commun.
13
,
1000
[PubMed]
118.
Pirchi
M.
,
Tsukanov
R.
,
Khamis
R.
,
Tomov
T.E.
,
Berger
Y.
,
Khara
D.C.
et al.
(
2016
)
Photon-by-photon hidden Markov model analysis for microsecond single-molecule FRET kinetics
.
J. Phys. Chem. B.
120
,
13065
13075
[PubMed]
119.
Ferreon
A.C.M.
,
Ferreon
J.C.
,
Wright
P.E.
and
Deniz
A.A.
(
2013
)
Modulation of allostery by protein intrinsic disorder
.
Nature
498
,
390
394
[PubMed]
120.
Chung
H.S.
,
Meng
F.
,
Kim
J.Y.
,
McHale
K.
,
Gopich
I.V.
and
Louis
J.M.
(
2017
)
Oligomerization of the tetramerization domain of p53 probed by two- and three-color single-molecule FRET
.
Proc. Natl. Acad. Sci. U.S.A.
114
,
E6812
E6821
[PubMed]
121.
Kim
J.Y.
and
Chung
H.S.
(
2020
)
Disordered proteins follow diverse transition paths as they fold and bind to a partner
.
Science
368
,
1253
1257
[PubMed]
122.
Ferreon
A.C.M.
,
Gambin
Y.
,
Lemke
E.A.
and
Deniz
A.A.
(
2009
)
Interplay of α-synuclein binding and conformational switching probed by single-molecule fluorescence
.
Proc. Natl. Acad. Sci. U.S.A.
106
,
5645
5650
123.
Wiggers
F.
,
Wohl
S.
,
Dubovetskyi
A.
,
Rosenblum
G.
,
Zheng
W.
and
Hofmann
H.
(
2022
)
Diffusion of a disordered protein on its folded ligand
.
Biophysical J.
121
,
200a
124.
Borgia
A.
,
Borgia
M.B.
,
Bugge
K.
,
Kissling
V.M.
,
P.O.
,
Fernandes
C.B.
et al.
(
2018
)
Extreme disorder in an ultrahigh-affinity protein complex
.
Nature
555
,
61
[PubMed]
125.
P.O.
,
D.
,
Sottini
A.
,
Nettels
D.
,
Borgia
M.B.
,
Borgia
A.
et al.
(
2022
)
Release of linker histone from the nucleosome driven by polyelectrolyte competition with a disordered protein
.
Nat. Chem.
14
,
224
231
[PubMed]
126.
Zosel
F.
,
D.
,
Nettels
D.
and
Schuler
B.
(
2018
)
A proline switch explains kinetic heterogeneity in a coupled folding and binding reaction
.
Nat. Commun.
9
,
3332
,
127.
Kim
J.Y.
,
Meng
F.
,
Yoo
J.
and
Chung
H.S.
(
2018
)
Diffusion-limited association of disordered protein by non-native electrostatic interactions
.
Nat. Commun.
9
,
4707
[PubMed]
128.
Hoffmann
A.
,
Nettels
D.
,
Clark
J.
,
Borgia
A.
,
S.E.
,
Clarke
J.
et al.
(
2011
)
Quantifying heterogeneity and conformational dynamics from single molecule FRET of diffusing molecules: recurrence analysis of single particles (RASP)
.
Phys. Chem. Chem. Phys.
13
,
1857
1871
[PubMed]
129.
Wunderlich
B.
,
Nettels
D.
,
Benke
S.
,
Clark
J.
,
Weidner
S.
,
Hofmann
H.
et al.
(
2013
)
Microfluidic mixer designed for performing single-molecule kinetics with confocal detection on timescales from milliseconds to minutes
.
Nat. Protoc.
8
,
1459
1474
[PubMed]
130.
Lemke
E.A.
,
Gambin
Y.
,
Vandelinder
V.
,
E.M.
,
Liu
H.W.
,
Schultz
P.G.
et al.
(
2009
)
Microfluidic device for single-molecule experiments with enhanced photostability
.
J. Am. Chem. Soc.
131
,
13610
13612
[PubMed]
131.
Tyagi
S.
,
VanDelinder
V.
,
Banterle
N.
,
Fuertes
G.
,
Milles
S.
,
Agez
M.
et al.
(
2014
)
Continuous throughput and long-term observation of single-molecule FRET without immobilization
.
Nat. Methods
11
,
297
300
[PubMed]
132.
Zosel
F.
,
Soranno
A.
,
Buholzer
K.J.
,
Nettels
D.
and
Schuler
B.
(
2020
)
Depletion interactions modulate the binding between disordered proteins in crowded environments
.
Proc. Natl. Acad. Sci. U.S.A.
117
,
13480
13489
[PubMed]
133.
Soranno
A.
,
Koenig
I.
,
Borgia
M.B.
,
Hofmann
H.
,
Zosel
F.
,
Nettels
D.
et al.
(
2014
)
Single-molecule spectroscopy reveals polymer effects of disordered proteins in crowded environments
.
Proc. Natl. Acad. Sci. U.S.A.
111
,
4874
4879
[PubMed]
134.
Sung
H.L.
,
Sengupta
A.
and
Nesbitt
D.
(
2021
)
Smaller molecules crowd better: Crowder size dependence revealed by single-molecule FRET studies and depletion force modeling analysis
.
J. Chem. Phys.
154
,
155101
[PubMed]
135.
Dupuis
N.F.
,
Holmstrom
E.D.
and
Nesbitt
D.J.
(
2014
)
Molecular-crowding effects on single-molecule RNA folding/unfolding thermodynamics and kinetics
.
Proc. Natl. Acad. Sci. U.S.A.
111
,
8464
8469
[PubMed]
136.
Schäfer
L.
(
2012
)
Excluded volume effects in polymer solutions: as explained by the renormalization group
,
Springer Berlin
Heidelberg, Germany
.
137.
Schuler
B.
,
König
I.
,
Soranno
A.
and
Nettels
D.
(
2021
)
Impact of in‐cell and in‐vitro crowding on the conformations and dynamics of an intrinsically disordered protein
.
Angew. Chem. Weinheim. Bergstr. Ger.
,
60
,
19
,
10724
10729
,
138.
Martin
E.W.
,
Holehouse
A.S.
,
Peran
I.
,
Farag
M.
,
Incicco
J.J.
,
Bremer
A.
et al.
(
2020
)
Valence and patterning of aromatic residues determine the phase behavior of prion-like domains
.
Science
367
,
694
699
[PubMed]
139.
Incicco
J.J.
,
Schuck
P.
and
Soranno
A.
A multi-step nucleation process determines the kinetics of prion-like domain phase separation
.
Nat. Commun.
,
12
,
2021
,
4513
,
140.
Shakya
A.
and
King
J.T.
(
2018
)
DNA local-flexibility-dependent assembly of phase-separated liquid droplets
.
Biophys. J.
115
,
1840
1847
[PubMed]
141.
Wei
M.T.
,
Elbaum-Garfinkle
S.
,
Holehouse
A.S.
,
Chen
C.C.H.
,
Feric
M.
,
Arnold
C.B.
et al.
(
2017
)
Phase behaviour of disordered proteins underlying low density and high permeability of liquid organelles
.
Nat Chem.
9
,
1118
1125
[PubMed]
142.
Alshareedah
I.
,
Moosa
M.M.
,
Raju
M.
,
Potoyan
D.A.
and
Banerjee
P.R.
(
2020
)
Phase transition of RNA−protein complexes into ordered hollow condensates
.
Proc. Natl. Acad. Sci. U.S.A.
117
,
15650
15658
143.
Mitrea
D.M.
,
Cika
J.A.
,
Guy
C.S.
,
Ban
D.
,
Banerjee
P.R.
,
Stanley
C.B.
et al.
(
2016
)
Nucleophosmin integrates within the nucleolus via multi-modal interactions with proteins displaying R-rich linear motifs and rRNA
.
Elife
5
,
[PubMed]
144.
Wen
J.
,
Hong
L.
,
Krainer
G.
,
Yao
Q.Q.
,
Knowles
T.P.J.
,
Wu
S.
et al.
(
2021
)
Conformational expansion of tau in condensates promotes irreversible aggregation
.
J. Am. Chem. Soc.
143
,
13056
13064
[PubMed]
This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY).
| 2023-02-07T11:48:55 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 12, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5498535633087158, "perplexity": 5166.938926571092}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500456.61/warc/CC-MAIN-20230207102930-20230207132930-00767.warc.gz"}
|
http://dlmf.nist.gov/27.14
|
# §27.14 Unrestricted Partitions
## §27.14(i) Partition Functions
A fundamental problem studies the number of ways can be written as a sum of positive integers , that is, the number of solutions of
27.14.1.
The number of summands is unrestricted, repetition is allowed, and the order of the summands is not taken into account. The corresponding unrestricted partition function is denoted by , and the summands are called parts; see §26.9(i). For example, because there are exactly seven partitions of 5: .
The number of partitions of into at most parts is denoted by ; again see §26.9(i).
## §27.14(ii) Generating Functions and Recursions
Euler introduced the reciprocal of the infinite product
27.14.2,
as a generating function for the function defined in §27.14(i):
with . Euler’s pentagonal number theorem states that
where the exponents 1, 2, 5, 7, 12, 15, are the pentagonal numbers, defined by
27.14.5.
Multiplying the power series for with that for and equating coefficients, we obtain the recursion formula
27.14.6
where is defined to be 0 if . Logarithmic differentiation of the generating function leads to another recursion:
27.14.7
where is defined by (27.2.10) with .
## §27.14(iii) Asymptotic Formulas
These recursions can be used to calculate , which grows very rapidly. For example, = 1905 69292, and . For large
where (Hardy and Ramanujan (1918)). Rademacher (1938) derives a convergent series that also provides an asymptotic expansion for :
where
and is a Dedekind sum given by
27.14.11
## §27.14(iv) Relation to Modular Functions
Dedekind sums occur in the transformation theory of the Dedekind modular function , defined by
27.14.12.
This is related to the function in (27.14.2) by
satisfies the following functional equation: if are integers with and , then
where and is given by (27.14.11).
For further properties of the function see §§23.1523.19.
## §27.14(v) Divisibility Properties
Ramanujan (1921) gives identities that imply divisibility properties of the partition function. For example, the Ramanujan identity
implies . Ramanujan also found that and for all . After decades of nearly fruitless searching for further congruences of this type, it was believed that no others existed, until it was shown in Ono (2000) that there are infinitely many. Ono proved that for every prime there are integers and such that for all . For example, .
## §27.14(vi) Ramanujan’s Tau Function
The discriminant function is defined by
27.14.16,
and satisfies the functional equation
27.14.17
if are integers with and .
The 24th power of in (27.14.12) with is an infinite product that generates a power series in with integer coefficients called Ramanujan’s tau function :
27.14.18.
The tau function is multiplicative and satisfies the more general relation:
Lehmer (1947) conjectures that is never 0 and verifies this for all by studying various congruences satisfied by , for example:
For further information on partitions and generating functions see Andrews (1976); also §§17.217.14, and §§26.926.10.
| 2013-05-24T05:29:11 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9731366038322449, "perplexity": 1026.502163202998}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00017-ip-10-60-113-184.ec2.internal.warc.gz"}
|
https://www.eurocontrol.int/prudata/dashboard/metadata/additional-asma-time/
|
## Contacts
Contact organisation EUROCONTROL: The European organisation for the safety of air navigation Contact organisation unit Directorate European Civil-Military Aviation - Performance Review Unit (DECMA/PRU) Contact name Performance Review Unit - EUROCONTROL Contact mail address 96 Rue de la Fusée1130 BrusselsBelgium Contact e-mail address [email protected]
## Statistical presentation
### Data description
The additional ASMA time is a proxy for the average arrival runway queuing time on the inbound traffic flow, during congestion periods at airports.
It is the difference between the actual ASMA time of a flight and a statistically determined unimpeded ASMA time based on ASMA times in periods of low traffic demand (see also unimpeded ASMA time - Methodology).
Uncertainty of approach conditions (e.g. pilot performance, landing clearance time, approach speed, wind conditions) makes traffic supply to runways a stochastic phenomenon. In order to ensure continuous traffic demand at runways and maximise runway usage, a minimum level of queuing is required. However, additional time in holding is detrimental to operations efficiency, fuel consumption and environment. Therefore, there exists a trade-off between approach efficiency and runway throughput.
As an output of the ATMAP Group, the additional ASMA time PI has been in use as a commonly agreed proxy for airport inefficiencies in the approach phase since 2008 and is compliant with the KPI definition in EU legislation.
### Classification system
Additional ASMA time is classified per Member State, with a breakdown for each airport subject to performance monitoring within the SES performance scheme.
### Sector coverage
The measures pertain to the Air Transport and Air Traffic Management Sector of the economy.
### Statistical concepts and definitions
The Arrival Sequencing and Metering Area (ASMA) is defined as a virtual cylinder with a 40-NM radius around the airport. The actual time spent by a flight between its last entry in the cylinder (Entry-time at 40 NM upstream) and the actual landing time (ALDT) is denoted ASMA transit time.
A Unimpeded ASMA time is determined for each group of flights with the same parameters (i.e. aircraft class, ASMA entry sector, arrival runway) and represents the transit time in non congested conditions.
The Additional ASMA time is the difference between the actual ASMA transit time and the unimpeded ASMA time calculated for non-congested conditions.
### Statistical unit
The statistical unit is the airport. Airport level data can also be aggregated to States level.
### Statistical population
The statistical population is the set of airports subject to performance monitoring within the SES performance scheme.
### Reference area
The reference area is the Single European Sky Area.
### Time coverage
2011 is the first year for which data is presented.
Not applicable.
## Unit of Measure
The additional ASMA time is measured in minutes per IFR arrival [min/arr].
## Reference period
• The first reference period (RP1) covers the calendar years 2012 to 2014 inclusive.
• The second reference period (RP2) covers the calendar years 2015 to 2019 inclusive.
• The third reference period (RP3) covers the calendar years 2020 to 2024 inclusive.
Unless decided otherwise, the following reference periods shall be of five calendar years.
## Institutional Mandate
Legal acts and agreements are established in the EU IR691/2010|Performance Regulation (691 / 2010), Commission Implementing Regulation (EU) No 390 / 2013 and Commission Implementing Regulation (EU) 2019/317.
## Release policy
### Release calendar
Additional ASMA time is released monthly with yearly aggregates.
Not applicable.
### User access
Information is disseminated to the general public via the SES Data Portal.
## Frequency of dissemination
Data is published monthly with the annual performance aggregate being available in January of the following year.
## Dissemination format
Information is disseminated to the general public via the SES Data Portal.
## Accessibility of documentation
### Documentation on methodology
As per the pertaining regulations (see Institutional Mandate).
Additional definitions of the terms used in the frame of the this KPI are available in the Metadata page.
### Quality documentation
There is no specific documentation on procedures applied for quality management and quality assessment.
## Quality Management
### Quality assurance
Data validation is performed by the Central Office for Delay Analysis (CODA), on behalf of PRU, on each data delivery by airports, and data validation report are returned to the data providers.
### Quality assessment
Raw data is cross-checked with various sources (Network manager, ANSP’s, airport operators, airport coordinators and air carriers). A quality threshold is established, and data that does not pass the quality threshold is rejected.
If a field is found to be blank, it is tried to fill the missing value from an alternative data source (i.e. a missing aircraft type in the airport data flow can be filled with information from the Network manager.)
### Completeness
The data is collected for all airports subject to performance monitoring within the SES performance scheme. Data completeness is determined each month as per the above-mentioned quality checks. Any missing data is reported to the provider.
## Relevance
The information is published for performance monitoring purposes in accordance with the relevant EU legislation.
### Completeness
The data is collected for the entire Single European Sky Area.
## Accuracy and reliability
### Overall accuracy
The accuracy of the measure is influenced by the availability of the entry point/runway configuration.
### Sampling error
There is no sampling and therefore no sampling error.
## Timeliness and punctuality
### Timeliness
The information is published each month - in general around 30 days after the end of the month in question.
### Punctuality
The internal databases are updated daily. The statistical processing is performed once per month.
## Comparability
### Comparability — geographical
The data is collected centrally by the EUROCONTROL Performance Review Unit (PRU) with delegation to the Central Office for Delay Analysis (CODA) and computed consistently for all airports subject to performance monitoring within the SES performance scheme.
The interpretation of the measure and comparisons across airports require due consideration of prevailing local circumstances (airport infrastructure, etc.)
### Comparability over time
Comparisons over time are valid.
## Coherence
### Coherence — cross domain
Checks have been carried out with a number of airports and there is generally a good level of coherence between the indicator results and the results from performance measurement systems of airport operators.
### Coherence — internal
Data is fully coherent from an internal perspective.
Not available.
## Data revision
Subject to changes (i.e. airspace design), there might be a need to change unimpeded times accordingly.
## Statistical processing
### Source data
In accordance with EU legislation, the data is collected centrally for all the airports subject to performance monitoring within the SES performance scheme.
The input variables used for the calculation are detailed in the Statistical concepts and definitions section.
### Frequency of data collection
The data is collected on a daily basis and transmitted for statistical processing on a monthly basis.
### Data collection
The data is collected by the EUROCONTROL Performance Review Unit (PRU) and the Central Office for Delay Analysis (CODA).
### Data validation
The data is validation as described in the Quality Management section.
### Data compilation
The ASMA area is defined as a 40-NM radius cylinder.
#### Calculation of the indicator
Let
• $$c$$, a combination of aircraft class, ASMA sectors and arrival runway, as described in the Unimpeded ASMA time - Methodology,
• $$f(c)$$ a flight characterised by a combination $$c$$,
• $$\mathrm{AcASMA}(f(c))$$ the actual ASMA transit time for a flight $$f(c)$$, i.e. the elapsed time between the last entry of the flight $$f(c)$$ in its ASMA sector and its actual landing time (ALDT),
• $$\mathrm{UASMA}(c)$$ the unimpeded ASMA time for a combination $$c$$.
The additional ASMA time $$\mathrm{AdASMA}(f(c))$$ is calculated for each flight $$f(c)$$ as the difference between the actual ASMA transit time $$\mathrm{AcASMA}(f(c))$$ of the flight and the unimpeded ASMA time $$\mathrm{UASMA}(c)$$: $\mathrm{AdASAM}(f(c)) = \mathrm{AcASMA}(f(c)) - \mathrm{UASMA}(c)$
The additional ASMA time $$\mathrm{AdASMA}(c)$$ for a given combination $$c$$ is the average of the additional ASMA time $$\mathrm{AdASMA}(f(c))$$ of all the flight $$f(c)$$ characterised by that combination $$c$$.
The additional ASMA time $$\mathrm{AdASMA}$$ for a given airport is the weighted average of the additional ASMA time $$\mathrm{AdASMA}(c)$$, for all the combinations $$c$$ at that airport with their probability of occurrence.
| 2023-03-21T02:12:26 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.374553382396698, "perplexity": 5542.802704471465}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296943589.10/warc/CC-MAIN-20230321002050-20230321032050-00659.warc.gz"}
|
https://zbmath.org/authors/?q=ai%3Avillani.cedric
|
zbMATH — the first resource for mathematics
Villani, Cédric
Compute Distance To:
Author ID: villani.cedric Published as: Villani, C.; Villani, Cedric; Villani, Cédric Homepage: http://cedricvillani.org External Links: MGP · Wikidata · dblp · GND Awards: EMS Prize (2008) · Fields Medal (2010)
Documents Indexed: 108 Publications since 1995, including 17 Books Biographic References: 7 Publications
all top 5
Co-Authors
45 single-authored 10 Desvillettes, Laurent 7 Figalli, Alessio 6 Mouhot, Clément 5 Toscani, Giuseppe 4 Rifford, Ludovic 3 Alexandre, Radjesvarane 3 Carrillo de la Plata, José Antonio 3 Martínez Gamba, Irene 3 Lott, John 3 Otto, Felix 3 Panferov, Vladislav A. 2 Bolley, François 2 Cartier, Pierre 2 Dhombres, Jean G. 2 Heinzmann, Gerhard 2 Maggi, Francesco 2 Markowich, Peter Alexander 2 McCann, Robert J. 2 Ollivier, Yann 1 Ambrosio, Luigi 1 Arnold, Anton 1 Banyaga, Augustin 1 Baudoin, Edmond 1 Bodineau, Thierry 1 Brenier, Yann 1 Buttazzo, Giuseppe 1 Caffarelli, Luis Ángel 1 Caglioti, Emanuele 1 Carlen, Eric Anders 1 Carvalho, Maria Conceição 1 Cederbaum, Carla 1 Comtet, Alain 1 Cordero-Erausquin, Dario 1 De Lellis, Camillo 1 Dickenstein, Alicia M. 1 Dolbeault, Jean 1 Gangbo, Wilfrid 1 Golse, François 1 Greuel, Gert-Martin 1 Grünberg, David 1 Grunewald, Natalie 1 Guillin, Arnaud 1 Jüngel, Ansgar 1 King, Henry C. 1 Le Roux, Jonathan 1 Lebowitz, Joel Louis 1 Lederman, Claudia B. 1 Lions, Pierre-Louis 1 Loeper, Grégoire 1 Loss, Michael 1 Lu, Peng 1 Luca, Florian 1 Milnor, John Willard 1 Moncorgé, Vincent 1 Nachbar, John H. 1 Nazaret, Bruno 1 Neudauer, Nancy Ann 1 Ni, Lei 1 Nordlinger, Bernard 1 Olla, Stefano 1 Pajot, Hervé 1 Pareschi, Lorenzo 1 Park, Hyungju 1 Rezakhanlou, Fraydoun 1 Salsa, Sandro 1 Shubin, Carol Ann 1 Székelyhidi, László jun. 1 Uzan, Jean-Philippe 1 Vazquez, Juan Luis 1 Waldschmidt, Michel 1 Weinstein, Jonathan 1 Wennberg, Bernt 1 Westdickenberg, Maria G.
all top 5
Serials
6 Archive for Rational Mechanics and Analysis 4 Journal of Statistical Physics 4 Journal de Mathématiques Pures et Appliquées. Neuvième Série 3 Communications in Mathematical Physics 3 Journal of Functional Analysis 2 Communications on Pure and Applied Mathematics 2 Acta Mathematica 2 Revista Matemática Iberoamericana 2 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 2 Communications in Partial Differential Equations 2 Notices of the American Mathematical Society 2 Calculus of Variations and Partial Differential Equations 2 European Mathematical Society Newsletter 2 Lecture Notes in Mathematics 2 Kinetic and Related Models 1 IEEE Transactions on Information Theory 1 Journal of Mathematical Physics 1 Nonlinearity 1 Transport Theory and Statistical Physics 1 Advances in Mathematics 1 American Journal of Mathematics 1 Duke Mathematical Journal 1 Gazette des Mathématiciens 1 Inventiones Mathematicae 1 Mathematische Zeitschrift 1 Memoirs of the American Mathematical Society 1 Monatshefte für Mathematik 1 Numerische Mathematik 1 Tohoku Mathematical Journal. Second Series 1 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 1 Probability Theory and Related Fields 1 SIAM Journal on Discrete Mathematics 1 Differential Geometry and its Applications 1 The Journal of Geometric Analysis 1 Comptes Rendus de l’Académie des Sciences. Série I 1 Annales de l’Institut Henri Poincaré. Probabilités et Statistiques 1 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 1 Séminaire Équations aux Dérivées Partielles 1 Journal of the Egyptian Mathematical Society 1 Methods and Applications of Analysis 1 Advances in Differential Equations 1 Discrete and Continuous Dynamical Systems 1 Matemática Contemporânea 1 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 1 Markov Processes and Related Fields 1 Bollettino della Unione Matematica Italiana. Serie VIII. Sezione B. Articoli di Ricerca Matematica 1 Annals of Mathematics. Second Series 1 M2AN. Mathematical Modelling and Numerical Analysis. ESAIM, European Series in Applied and Industrial Mathematics 1 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 1 Graduate Studies in Mathematics 1 Grundlehren der Mathematischen Wissenschaften 1 London Mathematical Society Lecture Note Series 1 Japanese Journal of Mathematics. 3rd Series 1 Matapli 1 La Tortue de Zénon
all top 5
Fields
49 Statistical mechanics, structure of matter (82-XX) 41 Partial differential equations (35-XX) 33 Fluid mechanics (76-XX) 18 History and biography (01-XX) 18 Calculus of variations and optimal control; optimization (49-XX) 18 Differential geometry (53-XX) 14 Probability theory and stochastic processes (60-XX) 10 General and overarching topics; collections (00-XX) 7 Global analysis, analysis on manifolds (58-XX) 6 Functional analysis (46-XX) 6 Operations research, mathematical programming (90-XX) 5 Measure and integration (28-XX) 5 Integral equations (45-XX) 4 Real functions (26-XX) 4 Operator theory (47-XX) 4 Information and communication theory, circuits (94-XX) 3 Dynamical systems and ergodic theory (37-XX) 2 Numerical analysis (65-XX) 2 Mechanics of deformable solids (74-XX) 2 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 1 Number theory (11-XX) 1 Potential theory (31-XX) 1 Geometry (51-XX) 1 Convex and discrete geometry (52-XX) 1 General topology (54-XX) 1 Statistics (62-XX) 1 Computer science (68-XX) 1 Mechanics of particles and systems (70-XX) 1 Biology and other natural sciences (92-XX) 1 Systems theory; control (93-XX) 1 Mathematics education (97-XX)
Citations contained in zbMATH Open
86 Publications have been cited 5,876 times in 3,519 Documents Cited by Year
Topics in optimal transportation. Zbl 1106.90001
Villani, Cédric
2003
Optimal transport. Old and new. Zbl 1156.53003
Villani, Cédric
2009
Ricci curvature for metric-measure spaces via optimal transport. Zbl 1178.53038
Lott, John; Villani, Cedric
2009
A review of mathematical topics in collisional kinetic theory. Zbl 1170.82369
Villani, Cédric
2002
Generalization of an inequality by Talagrand and links with the logarithmic Sobolev inequality. Zbl 0985.58019
Otto, F.; Villani, C.
2000
Kinetic equilibration rates for granular media and related equations: entropy dissipation and mass transportation estimates. Zbl 1073.35127
Carrillo, José A.; McCann, Robert J.; Villani, Cédric
2003
On a new class of weak solutions to the spatially homogeneous Boltzmann and Landau equations. Zbl 0912.45011
Villani, Cédric
1998
Contractions in the 2-Wasserstein length space and thermalization of granular media. Zbl 1082.76105
Carrillo, José A.; McCann, Robert J.; Villani, Cédric
2006
On the trend to global equilibrium for spatially inhomogeneous kinetic systems: the Boltzmann equation. Zbl 1162.82316
Desvillettes, L.; Villani, C.
2005
A mass-transportation approach to sharp Sobolev and Gagliardo-Nirenberg inequalities. Zbl 1048.26010
Cordero-Erausquin, D.; Nazaret, B.; Villani, C.
2004
Entropy dissipation and long-range interactions. Zbl 0968.76076
Alexandre, R.; Desvillettes, L.; Villani, C.; Wennberg, B.
2000
On the trend to global equilibrium in spatially inhomogeneous entropy-dissipating systems: The linear Fokker-Planck equation. Zbl 1029.82032
Desvillettes, L.; Villani, C.
2001
Hypocoercivity. Zbl 1197.35004
Villani, Cédric
2009
On Landau damping. Zbl 1239.82017
Mouhot, Clément; Villani, Cédric
2011
Stability of a 4th-order curvature condition arising in optimal transport theory. Zbl 1158.53036
Villani, C.
2008
On the spatially homogeneous Landau equation for hard potentials. I: Existence, uniqueness and smoothness. Zbl 0946.35109
Desvillettes, Laurent; Villani, Cédric
2000
On the Boltzmann equation for long-range interactions. Zbl 1029.82036
Alexandre, R.; Villani, C.
2002
On the spatially homogeneous Landau equation for hard potentials. II: H-theorem and applications. Zbl 0951.35130
Desvillettes, Laurent; Villani, Cédric
2000
Probability metrics and uniqueness of the solution to the Boltzmann equation for a Maxwell gas. Zbl 0958.82044
Toscani, G.; Villani, C.
1999
Weak curvature conditions and functional inequalities. Zbl 1119.53028
Lott, John; Villani, Cédric
2007
Quantitative concentration inequalities for empirical measures on non-compact spaces. Zbl 1113.60093
Bolley, François; Guillin, Arnaud; Villani, Cédric
2007
Cercignani’s conjecture is sometimes true and always almost true. Zbl 1041.82018
Villani, Cédric
2003
Optimal transportation and applications. Lectures given at the C. I. M. E. summer school, Martina Franca, Italy, September 2–8, 2001. Zbl 1013.00028
Ambrosio, Luigi; Brenier, Yann; Buttazzo, Giusseppe; Caffarelli, Luis A.; Salsa, S. (ed.); Villani, Cédric
2003
Regularity theory for the spatially homogeneous Boltzmann equation with cut-off. Zbl 1063.76086
Mouhot, Clément; Villani, Cédric
2004
On the Boltzmann equation for diffusively excited granular media. Zbl 1106.82031
Gamba, I. M.; Panferov, V.; Villani, C.
2004
On the Landau approximation in plasma physics. Zbl 1044.83007
Alexandre, R.; Villani, C.
2004
On the spatially homogeneous Landau equation for Maxwellian molecules. Zbl 0957.82029
Villani, C.
1998
Weighted Csiszár-Kullback-Pinsker inequalities and applications to transportation inequalities. Zbl 1087.60008
Bolley, François; Villani, Cédric
2005
Sharp entropy dissipation bounds and explicit rate of trend to equilibrium for the spatially homogeneous Boltzmann equation. Zbl 0944.35066
Toscani, G.; Villani, C.
1999
Upper Maxwellian bounds for the spatially homogeneous Boltzmann equation. Zbl 1273.76373
Gamba, I. M.; Panferov, V.; Villani, C.
2009
Local Aronson-Bénilan estimates and entropy formulae for porous medium and fast diffusion equations on manifolds. Zbl 1156.58015
Lu, Peng; Ni, Lei; Vázquez, Juan-Luis; Villani, Cédric
2009
On the trend to equilibrium for the Fokker-Planck equation: an interplay between physics and functional analysis. Zbl 1139.82326
Markowich, P. A.; Villani, C.
2000
Entropy and chaos in the Kac model. Zbl 1186.76675
Carlen, Eric A.; Carvalho, Maria C.; Le Roux, Jonathan; Loss, Michael; Villani, Cédric
2010
On the trend to equilibrium for some dissipative systems with slowly increasing a priori bounds. Zbl 1034.82032
Toscani, G.; Villani, C.
2000
Entropies and equilibria of many-particle systems: an essay on recent research. Zbl 1063.35109
Arnold, A.; Carrillo, J. A.; Desvillettes, L.; Dolbeault, J.; Jüngel, A.; Lederman, C.; Markowich, P. A.; Toscani, G.; Villani, C.
2004
Regularity of optimal transport in curved geometry: the nonfocal case. Zbl 1192.53041
Loeper, Grégoire; Villani, Cédric
2010
Mathematics of granular materials. Zbl 1134.82040
Villani, Cédric
2006
On the Cauchy problem for Landau equations: Sequential stability, global existence. Zbl 0856.35020
Villani, Cédric
1996
A two-scale approach to logarithmic Sobolev inequalities and the hydrodynamic limit. Zbl 1179.60068
Grunewald, Natalie; Otto, Felix; Villani, Cédric; Westdickenberg, Maria G.
2009
On a variant of Korn’s inequality arising in statistical mechanics. Zbl 1092.82032
Desvillettes, L.; Villani, Cédric
2002
Hamilton-Jacobi semigroup on length spaces and applications. Zbl 1210.53047
Lott, John; Villani, Cédric
2007
Nearly round spheres look convex. Zbl 1241.53031
Figalli, Alessio; Rifford, Ludovic; Villani, Cedric
2012
Hypocoercive diffusion operators. Zbl 1130.35027
Villani, Cédric
2006
Necessary and sufficient conditions for continuity of optimal transport maps on Riemannian manifolds. Zbl 1262.58013
Figalli, Alessio; Rifford, Ludovic; Villani, Cédric
2011
Balls have the worst best Sobolev inequalities. Zbl 1086.46021
Maggi, Francesco; Villani, Cédric
2005
A short proof of the “concavity of entropy power”. Zbl 0994.94018
Villani, Cédric
2000
Regularity estimates via the entropy dissipation for the spatially homogeneous Boltzmann equation without cut-off. Zbl 0934.45010
Villani, Cédric
1999
On the Ma-Trudinger-Wang curvature on surfaces. Zbl 1203.53034
Figalli, Alessio; Rifford, Ludovic; Villani, Cédric
2010
Spectral methods for the non cut-off Boltzmann equation and numerical grazing collision limit. Zbl 1106.65324
Pareschi, L.; Toscani, G.; Villani, C.
2003
Fisher information estimates for Boltzmann’s collision operator. Zbl 0918.60093
Villani, C.
1998
A curved Brunn-Minkowski inequality on the discrete hypercube, or: what is the Ricci curvature of the discrete hypercube? Zbl 1267.52010
Ollivier, Y.; Villani, C.
2012
Landau damping. Zbl 1247.82081
Mouhot, Clément; Villani, Cédric
2010
Celebrating Cercignani’s conjecture for the Boltzmann equation. Zbl 1217.82064
Desvillettes, Laurent; Mouhot, Clément; Villani, Cédric
2011
Balls have the worst best Sobolev inequalities. II: Variants and extensions. Zbl 1135.46016
Maggi, F.; Villani, C.
2008
Lyapunov functionals for boundary-driven nonlinear drift-diffusion equations. Zbl 1301.58017
Bodineau, Thierry; Lebowitz, Joel; Mouhot, Clément; Villani, Cédric
2014
Entropy production and convergence to equilibrium. Zbl 1128.76056
Villani, Cédric
2008
Optimal regularity for square roots. Zbl 0870.35017
Lions, Pierre-Louis; Villani, Cédric
1995
Trend to equilibrium for dissipative equations, functional inequalities and mass transportation. Zbl 1134.35375
Villani, Cédric
2004
An approximation lemma about the cut locus, with applications in optimal transport theory. Zbl 1172.53022
Figalli, Alessio; Villani, Cédric
2008
Comment on “Hypercontractivity of Hamilton-Jacobi equations” by S. G. Bobkov, I. Gentil and M. Ledoux. Zbl 1134.35312
Otto, Felix; Villani, Cédric
2001
Conservative forms of Boltzmann’s collision operator: Landau revisited. Zbl 0919.35140
Villani, Cédric
1999
Regularity of optimal transport and cut locus: from nonsmooth analysis to geometry to smooth analysis. Zbl 1225.49048
Villani, Cédric
2011
$$H$$-theorem and beyond: Boltzmann’s entropy in today’s mathematics. Zbl 1156.82313
Villani, Cédric
2008
Hydrodynamic limits of Boltzmann’s equation (following C. Bardos, F. Golse, C. D. Levermore, P.-L. Lions, N. Masmoudi, L. Saint-Raymond). Zbl 1119.82037
Villani, Cédric
2002
Decrease of the Fisher information for solutions of the spatially homogeneous Landau equation with Maxwellian molecules. Zbl 1010.82023
Villani, C.
2000
Synthetic theory of Ricci curvature bounds. Zbl 1353.53019
Villani, Cédric
2016
Optimal transportation, dissipative PDE’s and functional inequalities. Zbl 1039.35147
Villani, Cedric
2003
Homogeneous cooling states are not always good approximations to granular flows. Zbl 1053.74012
Caglioti, E.; Villani, C.
2002
Entropic methods for the study of the long time behavior of kinetic equations. Zbl 1038.82073
Desvillettes, L.; Villani, C.
2001
Tangent cut loci on surfaces. Zbl 1217.53038
Figalli, A.; Rifford, L.; Villani, C.
2011
Hypocoercive diffusion operators. Zbl 1178.35306
Villani, Cédric
2007
Optimal transport. Theory and applications. Proceedings of the summer school ‘Optimal transportation: theory and applications’, Fourier Institute, Grenoble, France. Zbl 1301.00076
Ollivier, Yann (ed.); Pajot, Hervé (ed.); Villani, Cédric (ed.)
2014
The living theorem. Zbl 1290.01002
Villani, Cédric
2012
Optimal transport and Ricci curvature. Zbl 1141.53030
Villani, Cédric
2006
Entropy production and convergence to equilibrium for the Boltzmann equation. Zbl 1221.82082
Villani, Cédric
2005
(Ir)reversibility and entropy. Zbl 1320.82036
Villani, Cédric
2013
Landau damping. Zbl 1307.76087
Villani, Cédric
2013
Optimal transport and curvature. Zbl 1247.53003
Figalli, Alessio; Villani, Cédric
2011
Entropy methods for the Boltzmann equation. Lectures from a special semester at the Centre Émil Borel, Instititut H. Poincaré, Paris 2001. Zbl 1125.76001
Rezakhanlou, Fraydoun; Villani, Cédric; Golse, François (ed.); Olla, Stefano (ed.)
2008
Strong displacement convexity on Riemannian manifolds. Zbl 1125.53026
Figalli, A.; Villani, C.
2007
(Ir)reversibility and entropy. Zbl 1259.82089
Villani, Cédric
2012
Landau damping. Zbl 1230.82042
Villani, Cédric
2011
The Scheffer-Shnirelman paradox revisited from the viewpoint of convex integration (after C. De Lellis and L. Szḱelyhidi). Zbl 1404.35338
Villani, Cédric
2010
Rate of convergence toward the equilibrium in degenerate settings. Zbl 1069.35011
Desvillettes, L.; Villani, C.
2004
On the inelastic Boltzmann equation with diffusive forcing. Zbl 1032.76065
Gamba, Irene M.; Panferov, Vladislav; Villani, Cedric
2002
On the trend to equilibrium for kinetic equations. Zbl 1128.82303
Villani, C.
2002
Synthetic theory of Ricci curvature bounds. Zbl 1353.53019
Villani, Cédric
2016
Lyapunov functionals for boundary-driven nonlinear drift-diffusion equations. Zbl 1301.58017
Bodineau, Thierry; Lebowitz, Joel; Mouhot, Clément; Villani, Cédric
2014
Optimal transport. Theory and applications. Proceedings of the summer school ‘Optimal transportation: theory and applications’, Fourier Institute, Grenoble, France. Zbl 1301.00076
Ollivier, Yann (ed.); Pajot, Hervé (ed.); Villani, Cédric (ed.)
2014
(Ir)reversibility and entropy. Zbl 1320.82036
Villani, Cédric
2013
Landau damping. Zbl 1307.76087
Villani, Cédric
2013
Nearly round spheres look convex. Zbl 1241.53031
Figalli, Alessio; Rifford, Ludovic; Villani, Cedric
2012
A curved Brunn-Minkowski inequality on the discrete hypercube, or: what is the Ricci curvature of the discrete hypercube? Zbl 1267.52010
Ollivier, Y.; Villani, C.
2012
The living theorem. Zbl 1290.01002
Villani, Cédric
2012
(Ir)reversibility and entropy. Zbl 1259.82089
Villani, Cédric
2012
On Landau damping. Zbl 1239.82017
Mouhot, Clément; Villani, Cédric
2011
Necessary and sufficient conditions for continuity of optimal transport maps on Riemannian manifolds. Zbl 1262.58013
Figalli, Alessio; Rifford, Ludovic; Villani, Cédric
2011
Celebrating Cercignani’s conjecture for the Boltzmann equation. Zbl 1217.82064
Desvillettes, Laurent; Mouhot, Clément; Villani, Cédric
2011
Regularity of optimal transport and cut locus: from nonsmooth analysis to geometry to smooth analysis. Zbl 1225.49048
Villani, Cédric
2011
Tangent cut loci on surfaces. Zbl 1217.53038
Figalli, A.; Rifford, L.; Villani, C.
2011
Optimal transport and curvature. Zbl 1247.53003
Figalli, Alessio; Villani, Cédric
2011
Landau damping. Zbl 1230.82042
Villani, Cédric
2011
Entropy and chaos in the Kac model. Zbl 1186.76675
Carlen, Eric A.; Carvalho, Maria C.; Le Roux, Jonathan; Loss, Michael; Villani, Cédric
2010
Regularity of optimal transport in curved geometry: the nonfocal case. Zbl 1192.53041
Loeper, Grégoire; Villani, Cédric
2010
On the Ma-Trudinger-Wang curvature on surfaces. Zbl 1203.53034
Figalli, Alessio; Rifford, Ludovic; Villani, Cédric
2010
Landau damping. Zbl 1247.82081
Mouhot, Clément; Villani, Cédric
2010
The Scheffer-Shnirelman paradox revisited from the viewpoint of convex integration (after C. De Lellis and L. Szḱelyhidi). Zbl 1404.35338
Villani, Cédric
2010
Optimal transport. Old and new. Zbl 1156.53003
Villani, Cédric
2009
Ricci curvature for metric-measure spaces via optimal transport. Zbl 1178.53038
Lott, John; Villani, Cedric
2009
Hypocoercivity. Zbl 1197.35004
Villani, Cédric
2009
Upper Maxwellian bounds for the spatially homogeneous Boltzmann equation. Zbl 1273.76373
Gamba, I. M.; Panferov, V.; Villani, C.
2009
Local Aronson-Bénilan estimates and entropy formulae for porous medium and fast diffusion equations on manifolds. Zbl 1156.58015
Lu, Peng; Ni, Lei; Vázquez, Juan-Luis; Villani, Cédric
2009
A two-scale approach to logarithmic Sobolev inequalities and the hydrodynamic limit. Zbl 1179.60068
Grunewald, Natalie; Otto, Felix; Villani, Cédric; Westdickenberg, Maria G.
2009
Stability of a 4th-order curvature condition arising in optimal transport theory. Zbl 1158.53036
Villani, C.
2008
Balls have the worst best Sobolev inequalities. II: Variants and extensions. Zbl 1135.46016
Maggi, F.; Villani, C.
2008
Entropy production and convergence to equilibrium. Zbl 1128.76056
Villani, Cédric
2008
An approximation lemma about the cut locus, with applications in optimal transport theory. Zbl 1172.53022
Figalli, Alessio; Villani, Cédric
2008
$$H$$-theorem and beyond: Boltzmann’s entropy in today’s mathematics. Zbl 1156.82313
Villani, Cédric
2008
Entropy methods for the Boltzmann equation. Lectures from a special semester at the Centre Émil Borel, Instititut H. Poincaré, Paris 2001. Zbl 1125.76001
Rezakhanlou, Fraydoun; Villani, Cédric; Golse, François (ed.); Olla, Stefano (ed.)
2008
Weak curvature conditions and functional inequalities. Zbl 1119.53028
Lott, John; Villani, Cédric
2007
Quantitative concentration inequalities for empirical measures on non-compact spaces. Zbl 1113.60093
Bolley, François; Guillin, Arnaud; Villani, Cédric
2007
Hamilton-Jacobi semigroup on length spaces and applications. Zbl 1210.53047
Lott, John; Villani, Cédric
2007
Hypocoercive diffusion operators. Zbl 1178.35306
Villani, Cédric
2007
Strong displacement convexity on Riemannian manifolds. Zbl 1125.53026
Figalli, A.; Villani, C.
2007
Contractions in the 2-Wasserstein length space and thermalization of granular media. Zbl 1082.76105
Carrillo, José A.; McCann, Robert J.; Villani, Cédric
2006
Mathematics of granular materials. Zbl 1134.82040
Villani, Cédric
2006
Hypocoercive diffusion operators. Zbl 1130.35027
Villani, Cédric
2006
Optimal transport and Ricci curvature. Zbl 1141.53030
Villani, Cédric
2006
On the trend to global equilibrium for spatially inhomogeneous kinetic systems: the Boltzmann equation. Zbl 1162.82316
Desvillettes, L.; Villani, C.
2005
Weighted Csiszár-Kullback-Pinsker inequalities and applications to transportation inequalities. Zbl 1087.60008
Bolley, François; Villani, Cédric
2005
Balls have the worst best Sobolev inequalities. Zbl 1086.46021
Maggi, Francesco; Villani, Cédric
2005
Entropy production and convergence to equilibrium for the Boltzmann equation. Zbl 1221.82082
Villani, Cédric
2005
A mass-transportation approach to sharp Sobolev and Gagliardo-Nirenberg inequalities. Zbl 1048.26010
Cordero-Erausquin, D.; Nazaret, B.; Villani, C.
2004
Regularity theory for the spatially homogeneous Boltzmann equation with cut-off. Zbl 1063.76086
Mouhot, Clément; Villani, Cédric
2004
On the Boltzmann equation for diffusively excited granular media. Zbl 1106.82031
Gamba, I. M.; Panferov, V.; Villani, C.
2004
On the Landau approximation in plasma physics. Zbl 1044.83007
Alexandre, R.; Villani, C.
2004
Entropies and equilibria of many-particle systems: an essay on recent research. Zbl 1063.35109
Arnold, A.; Carrillo, J. A.; Desvillettes, L.; Dolbeault, J.; Jüngel, A.; Lederman, C.; Markowich, P. A.; Toscani, G.; Villani, C.
2004
Trend to equilibrium for dissipative equations, functional inequalities and mass transportation. Zbl 1134.35375
Villani, Cédric
2004
Rate of convergence toward the equilibrium in degenerate settings. Zbl 1069.35011
Desvillettes, L.; Villani, C.
2004
Topics in optimal transportation. Zbl 1106.90001
Villani, Cédric
2003
Kinetic equilibration rates for granular media and related equations: entropy dissipation and mass transportation estimates. Zbl 1073.35127
Carrillo, José A.; McCann, Robert J.; Villani, Cédric
2003
Cercignani’s conjecture is sometimes true and always almost true. Zbl 1041.82018
Villani, Cédric
2003
Optimal transportation and applications. Lectures given at the C. I. M. E. summer school, Martina Franca, Italy, September 2–8, 2001. Zbl 1013.00028
Ambrosio, Luigi; Brenier, Yann; Buttazzo, Giusseppe; Caffarelli, Luis A.; Salsa, S. (ed.); Villani, Cédric
2003
Spectral methods for the non cut-off Boltzmann equation and numerical grazing collision limit. Zbl 1106.65324
Pareschi, L.; Toscani, G.; Villani, C.
2003
Optimal transportation, dissipative PDE’s and functional inequalities. Zbl 1039.35147
Villani, Cedric
2003
A review of mathematical topics in collisional kinetic theory. Zbl 1170.82369
Villani, Cédric
2002
On the Boltzmann equation for long-range interactions. Zbl 1029.82036
Alexandre, R.; Villani, C.
2002
On a variant of Korn’s inequality arising in statistical mechanics. Zbl 1092.82032
Desvillettes, L.; Villani, Cédric
2002
Hydrodynamic limits of Boltzmann’s equation (following C. Bardos, F. Golse, C. D. Levermore, P.-L. Lions, N. Masmoudi, L. Saint-Raymond). Zbl 1119.82037
Villani, Cédric
2002
Homogeneous cooling states are not always good approximations to granular flows. Zbl 1053.74012
Caglioti, E.; Villani, C.
2002
On the inelastic Boltzmann equation with diffusive forcing. Zbl 1032.76065
Gamba, Irene M.; Panferov, Vladislav; Villani, Cedric
2002
On the trend to equilibrium for kinetic equations. Zbl 1128.82303
Villani, C.
2002
On the trend to global equilibrium in spatially inhomogeneous entropy-dissipating systems: The linear Fokker-Planck equation. Zbl 1029.82032
Desvillettes, L.; Villani, C.
2001
Comment on “Hypercontractivity of Hamilton-Jacobi equations” by S. G. Bobkov, I. Gentil and M. Ledoux. Zbl 1134.35312
Otto, Felix; Villani, Cédric
2001
Entropic methods for the study of the long time behavior of kinetic equations. Zbl 1038.82073
Desvillettes, L.; Villani, C.
2001
Generalization of an inequality by Talagrand and links with the logarithmic Sobolev inequality. Zbl 0985.58019
Otto, F.; Villani, C.
2000
Entropy dissipation and long-range interactions. Zbl 0968.76076
Alexandre, R.; Desvillettes, L.; Villani, C.; Wennberg, B.
2000
On the spatially homogeneous Landau equation for hard potentials. I: Existence, uniqueness and smoothness. Zbl 0946.35109
Desvillettes, Laurent; Villani, Cédric
2000
On the spatially homogeneous Landau equation for hard potentials. II: H-theorem and applications. Zbl 0951.35130
Desvillettes, Laurent; Villani, Cédric
2000
On the trend to equilibrium for the Fokker-Planck equation: an interplay between physics and functional analysis. Zbl 1139.82326
Markowich, P. A.; Villani, C.
2000
On the trend to equilibrium for some dissipative systems with slowly increasing a priori bounds. Zbl 1034.82032
Toscani, G.; Villani, C.
2000
A short proof of the “concavity of entropy power”. Zbl 0994.94018
Villani, Cédric
2000
Decrease of the Fisher information for solutions of the spatially homogeneous Landau equation with Maxwellian molecules. Zbl 1010.82023
Villani, C.
2000
Probability metrics and uniqueness of the solution to the Boltzmann equation for a Maxwell gas. Zbl 0958.82044
Toscani, G.; Villani, C.
1999
Sharp entropy dissipation bounds and explicit rate of trend to equilibrium for the spatially homogeneous Boltzmann equation. Zbl 0944.35066
Toscani, G.; Villani, C.
1999
Regularity estimates via the entropy dissipation for the spatially homogeneous Boltzmann equation without cut-off. Zbl 0934.45010
Villani, Cédric
1999
Conservative forms of Boltzmann’s collision operator: Landau revisited. Zbl 0919.35140
Villani, Cédric
1999
On a new class of weak solutions to the spatially homogeneous Boltzmann and Landau equations. Zbl 0912.45011
Villani, Cédric
1998
On the spatially homogeneous Landau equation for Maxwellian molecules. Zbl 0957.82029
Villani, C.
1998
Fisher information estimates for Boltzmann’s collision operator. Zbl 0918.60093
Villani, C.
1998
On the Cauchy problem for Landau equations: Sequential stability, global existence. Zbl 0856.35020
Villani, Cédric
1996
Optimal regularity for square roots. Zbl 0870.35017
Lions, Pierre-Louis; Villani, Cédric
1995
all top 5
Cited by 3,398 Authors
90 Carrillo de la Plata, José Antonio 39 Figalli, Alessio 39 Toscani, Giuseppe 37 Mouhot, Clément 35 Ambrosio, Luigi 35 Villani, Cédric 35 Yang, Tong 33 Sturm, Karl-Theodor 29 Gigli, Nicola 29 Santambrogio, Filippo 28 Morimoto, Yoshinori 27 Desvillettes, Laurent 27 Savaré, Giuseppe 26 McCann, Robert J. 25 Carlier, Guillaume 25 Wang, Feng-Yu 23 Duan, Renjun 23 Xu, Chao-Jiang 22 Dolbeault, Jean 22 Guillin, Arnaud 22 Mischler, Stéphane 21 Martínez Gamba, Irene 21 Kolesnikov, Alexander V. 21 Li, Wuchen 20 Carlen, Eric Anders 19 Pareschi, Lorenzo 19 Strain, Robert M. 18 Agueh, Martial 18 Alexandre, Radjesvarane 18 Ha, Seung-Yeal 18 Yu, Hongjun 18 Yun, Seok-Bae 17 Bogachev, Vladimir Igorevich 17 Gentil, Ivan 17 Kim, Young-Heon 17 Ukai, Seiji 16 Gozlan, Nathael 16 Mondino, Andrea 16 Peletier, Mark Adriaan 16 Wu, Liming 15 Beiglböck, Mathias 15 Fournier, Nicolas G. 15 Shao, Jinghai 14 Cañizo, José Alfredo 14 Erbar, Matthias 14 Fathi, Max 14 Guo, Yan 14 Matthes, Daniel 14 Ohta, Shin-ichi 13 Alonso, Ricardo J. 13 Bedrossian, Jacob 13 Bolley, François 13 Di Francesco, Marco 13 Ghoussoub, Nassif A. 13 Lods, Bertrand 13 Maas, Jan 13 Peyré, Gabriel 13 Slepčev, Dejan 13 Velázquez, Juan J. L. 13 Wolansky, Gershon 13 Zhao, Huijiang 12 Cavalletti, Fabio 12 Chen, Yongxin 12 Choi, Young-Pil 12 Fellner, Klemens 12 Golse, François 12 Honda, Shouhei 12 Liu, Jianguo 12 Liu, Shuangqian 12 Pavliotis, Grigorios A. 12 Rifford, Ludovic 12 Vorotnikov, Dmitry A. 11 Brenier, Yann 11 Briant, Marc 11 Ekeland, Ivar 11 Gangbo, Wilfrid 11 Georgiou, Tryphon T. 11 Ketterer, Christian 11 Ledoux, Michel 11 Lee, Paul W. Y. 11 Léonard, Christian 11 Li, Weixi 11 Lim, Yongdo 11 Rossi, Julio Daniel 11 Schlichting, André 10 Blanchet, Adrien 10 Cianchi, Andrea 10 Galichon, Alfred 10 Gallouët, Thomas O. 10 He, Lingbing 10 Hu, Jingwei 10 Jabin, Pierre-Emmanuel 10 Loeper, Grégoire 10 Loss, Michael 10 Lu, Xuguang 10 Malrieu, Florent 10 Mazón Ruiz, José M. 10 Otto, Felix 10 Piccoli, Benedetto 10 Rajala, Tapio ...and 3,298 more Authors
all top 5
Cited in 407 Serials
154 Journal of Functional Analysis 128 Journal of Statistical Physics 117 Archive for Rational Mechanics and Analysis 115 Journal of Differential Equations 108 Calculus of Variations and Partial Differential Equations 89 Communications in Mathematical Physics 82 SIAM Journal on Mathematical Analysis 80 Journal de Mathématiques Pures et Appliquées. Neuvième Série 79 Journal of Mathematical Analysis and Applications 65 Kinetic and Related Models 57 Advances in Mathematics 57 Stochastic Processes and their Applications 56 Discrete and Continuous Dynamical Systems 51 Journal of Computational Physics 51 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 49 Probability Theory and Related Fields 48 Comptes Rendus. Mathématique. Académie des Sciences, Paris 45 The Annals of Probability 45 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 43 Journal of Mathematical Physics 43 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 39 The Annals of Applied Probability 38 Communications in Partial Differential Equations 35 Potential Analysis 34 Proceedings of the American Mathematical Society 33 The Journal of Geometric Analysis 32 Transactions of the American Mathematical Society 29 Bernoulli 28 Annales de l’Institut Henri Poincaré. Probabilités et Statistiques 27 SIAM Journal on Control and Optimization 26 SIAM Journal on Scientific Computing 25 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 23 Mathematische Annalen 22 Communications on Pure and Applied Mathematics 21 Inventiones Mathematicae 21 Geometric and Functional Analysis. GAFA 20 Journal of Scientific Computing 20 Bulletin des Sciences Mathématiques 18 Electronic Journal of Probability 18 SIAM Journal on Imaging Sciences 17 SIAM Journal on Numerical Analysis 17 Analysis and Geometry in Metric Spaces 16 Acta Applicandae Mathematicae 16 Journal of the European Mathematical Society (JEMS) 15 Mathematics of Computation 15 Quarterly of Applied Mathematics 15 Statistics & Probability Letters 15 Physica D 15 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 14 Journal of Multivariate Analysis 14 Manuscripta Mathematica 14 Memoirs of the American Mathematical Society 14 SIAM Journal on Applied Mathematics 14 Communications on Pure and Applied Analysis 14 Electronic Journal of Statistics 14 Science China. Mathematics 13 Nonlinearity 13 Numerische Mathematik 13 Journal of Mathematical Sciences (New York) 13 Annales Henri Poincaré 12 Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Serie IX. Rendiconti Lincei. Matematica e Applicazioni 12 Bulletin of the American Mathematical Society. New Series 12 Journal of Mathematical Imaging and Vision 12 Journal of Nonlinear Science 12 Doklady Mathematics 12 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 11 The Annals of Statistics 11 Economic Theory 11 Multiscale Modeling & Simulation 11 Analysis and Applications (Singapore) 11 SIAM/ASA Journal on Uncertainty Quantification 11 Séminaire Laurent Schwartz. EDP et Applications 10 Applied Mathematics and Optimization 10 Geometriae Dedicata 10 Journal für die Reine und Angewandte Mathematik 10 Ergodic Theory and Dynamical Systems 10 Applied Mathematics Letters 10 European Series in Applied and Industrial Mathematics (ESAIM): Probability and Statistics 10 Communications in Contemporary Mathematics 10 Entropy 10 SIAM Journal on Applied Dynamical Systems 9 ZAMP. Zeitschrift für angewandte Mathematik und Physik 9 Annali di Matematica Pura ed Applicata. Serie Quarta 9 Duke Mathematical Journal 9 Journal of Optimization Theory and Applications 9 Chinese Annals of Mathematics. Series B 9 Stochastic Analysis and Applications 9 Applied and Computational Harmonic Analysis 9 NoDEA. Nonlinear Differential Equations and Applications 9 Electronic Communications in Probability 9 Foundations of Computational Mathematics 9 Discrete and Continuous Dynamical Systems. Series B 9 Advances in Calculus of Variations 8 Mathematische Zeitschrift 8 Discrete & Computational Geometry 8 Revista Matemática Iberoamericana 8 European Journal of Applied Mathematics 8 M2AN. Mathematical Modelling and Numerical Analysis. ESAIM, European Series in Applied and Industrial Mathematics 8 Journal of Evolution Equations 8 Frontiers of Mathematics in China ...and 307 more Serials
all top 5
Cited in 59 Fields
1,561 Partial differential equations (35-XX) 832 Probability theory and stochastic processes (60-XX) 715 Statistical mechanics, structure of matter (82-XX) 655 Calculus of variations and optimal control; optimization (49-XX) 491 Fluid mechanics (76-XX) 434 Differential geometry (53-XX) 344 Numerical analysis (65-XX) 271 Global analysis, analysis on manifolds (58-XX) 222 Functional analysis (46-XX) 179 Operations research, mathematical programming (90-XX) 178 Statistics (62-XX) 156 Operator theory (47-XX) 152 Measure and integration (28-XX) 152 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 150 Real functions (26-XX) 147 Dynamical systems and ergodic theory (37-XX) 140 Biology and other natural sciences (92-XX) 101 Systems theory; control (93-XX) 82 Information and communication theory, circuits (94-XX) 80 Convex and discrete geometry (52-XX) 80 Quantum theory (81-XX) 76 Integral equations (45-XX) 71 Computer science (68-XX) 55 Ordinary differential equations (34-XX) 53 Combinatorics (05-XX) 49 Mechanics of particles and systems (70-XX) 42 General topology (54-XX) 36 Potential theory (31-XX) 36 Mechanics of deformable solids (74-XX) 31 Difference and functional equations (39-XX) 29 Optics, electromagnetic theory (78-XX) 28 Geometry (51-XX) 27 Functions of a complex variable (30-XX) 27 Harmonic analysis on Euclidean spaces (42-XX) 25 Relativity and gravitational theory (83-XX) 23 Linear and multilinear algebra; matrix theory (15-XX) 22 Classical thermodynamics, heat transfer (80-XX) 17 Geophysics (86-XX) 14 Topological groups, Lie groups (22-XX) 12 Astronomy and astrophysics (85-XX) 11 Several complex variables and analytic spaces (32-XX) 10 History and biography (01-XX) 8 Abstract harmonic analysis (43-XX) 8 Manifolds and cell complexes (57-XX) 7 Number theory (11-XX) 7 Approximations and expansions (41-XX) 7 Algebraic topology (55-XX) 6 General and overarching topics; collections (00-XX) 6 Special functions (33-XX) 5 Category theory; homological algebra (18-XX) 3 Mathematical logic and foundations (03-XX) 3 Nonassociative rings and algebras (17-XX) 2 Order, lattices, ordered algebraic structures (06-XX) 2 Algebraic geometry (14-XX) 2 Integral transforms, operational calculus (44-XX) 1 Commutative algebra (13-XX) 1 Group theory and generalizations (20-XX) 1 Sequences, series, summability (40-XX) 1 Mathematics education (97-XX)
Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-06-16T09:07:54 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5213691592216492, "perplexity": 7193.560649872392}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623487622234.42/warc/CC-MAIN-20210616063154-20210616093154-00527.warc.gz"}
|
https://pos.sissa.it/395/184/
|
Volume 395 - 37th International Cosmic Ray Conference (ICRC2021) - CRI - Cosmic Ray Indirect
Electrical signals induced in detectors by cosmic rays: a reciprocal look at electrodynamics
P. Windischhofer* and W. Riegler
Full text: pdf
Pre-published on: July 05, 2021
Published on:
Abstract
The computation of the radio emissions produced by an extended air shower at the location of the detector is a fundamental problem in the indirect detection of cosmic rays. Conventionally, simulation programs compute and sum the contributions from all particles in the shower, and then propagate this field through the environment and the signal processing chain of the experiment. This contribution presents a complementary formulation, which encodes all properties of the detector and its environment in a specially constructed electric field distribution, the weighting field’’. Once the weighting field is known for a particular situation, the electrical signal produced in the detector can be computed very efficiently by convolving the weighting field with the trajectories of the charged particles in the shower.
DOI: https://doi.org/10.22323/1.395.0184
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2021-10-26T19:17:22 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4878429174423218, "perplexity": 1246.6520279887322}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587915.41/warc/CC-MAIN-20211026165817-20211026195817-00537.warc.gz"}
|
http://xmm-tools.cosmos.esa.int/external/sas/current/doc/ommosaic/node20.html
|
XMM-Newton Science Analysis System
ommosaic (ommosaic-2.11) [xmmsas_20211130_0941-20.0.0]
## Cross-correlation
The cross-correlation coefficient, R between 2 images, , with offsets between their x and y origins, respectively, is computed from
R ,
where ,
,
,
where nx and ny are the image dimensions in the x and y directions, respectively. In the above formulae it is assumed that the mean image values have been subtracted from the images. R can vary from -1 to +1.
XMM-Newton SOC -- 2021-11-30
| 2022-09-27T04:11:09 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8700733780860901, "perplexity": 3263.401937964666}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030334987.39/warc/CC-MAIN-20220927033539-20220927063539-00391.warc.gz"}
|
https://par.nsf.gov/biblio/10369705-impact-cosmic-rays-kinematics-circumgalactic-medium
|
The Impact of Cosmic Rays on the Kinematics of the Circumgalactic Medium
Abstract
We use hydrodynamical simulations of two Milky Way–mass galaxies to demonstrate the impact of cosmic-ray pressure on the kinematics of cool and warm circumgalactic gas. Consistent with previous studies, we find that cosmic-ray pressure can dominate over thermal pressure in the inner 50 kpc of the circumgalactic medium (CGM), creating an overall cooler CGM than that of similar galaxy simulations run without cosmic rays. We generate synthetic sight lines of the simulated galaxies’ CGM and use Voigt profile-fitting methods to extract ion column densities, Doppler-bparameters, and velocity centroids of individual absorbers. We directly compare these synthetic spectral line fits with HST/COS CGM absorption-line data analyses, which tend to show that metallic species with a wide range of ionization potential energies are often kinematically aligned. Compared to the Milky Way simulation run without cosmic rays, the presence of cosmic-ray pressure in the inner CGM creates narrower Oviabsorption features and broader Siiiiabsorption features, a quality that is more consistent with observational data. Additionally, because the cool gas is buoyant due to nonthermal cosmic-ray pressure support, the velocity centroids of both cool and warm gas tend to align in the simulated Milky Way with feedback from cosmic rays. Our study demonstrates that more »
Authors:
; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10369705
Journal Name:
The Astrophysical Journal
Volume:
935
Issue:
2
Page Range or eLocation-ID:
Article No. 69
ISSN:
0004-637X
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
##### More Like this
1. We use hydrodynamical simulations of two Milky Way-mass galaxies to demonstrate the impact of cosmic-ray pressure on the kinematics of cool and warm circumgalactic gas. Consistent with previous studies, we find that cosmic-ray pressure can dominate over thermal pressure in the inner 50 kpc of the circumgalactic medium (CGM), creating an overall cooler CGM than that of similar galaxy simulations run without cosmic rays. We generate synthetic sightlines of the simulated galaxies' CGM and use Voigt profile fitting methods to extract ion column densities, Doppler-b parameters, and velocity centroids of individual absorbers. We directly compare these synthetic spectral line fits with HST/COS CGM absorption-line data analyses, which tend to show that metallic species with a wide range of ionization potential energies are often kinematically aligned. Compared to the Milky-Way simulation run without cosmic rays, the presence of cosmic-ray pressure in the inner CGM creates narrower OVI absorption features and broader SiIII absorption features, a quality which is more consistent with observational data. Additionally, because the cool gas is buoyant due to nonthermal cosmic-ray pressure support, the velocity centroids of both cool and warm gas tend to align in the simulated Milky Way with feedback from cosmic rays. Our study demonstratesmore »
2. Abstract
Absorption-line measurements of the circumgalactic medium (CGM) display a highly nonuniform distribution of lower ionization state species accompanied by more widespread higher ionization state material. This suggests that the CGM is a dynamic, multiphase medium, such as arises in the presence of turbulence. To better understand this evolution, we perform hydrodynamic and magnetohydrodynamic (MHD) simulations of the CGM surrounding Milky Way–like galaxies. In both cases, the CGM is initially in hydrostatic balance in a 1012Mdark matter gravitational potential, and the simulations include rotation in the inner halo and turbulence that decreases radially. They also track ionizations, recombinations, and species-by-species radiative cooling in the presence of the redshift-zero UV background, employing the MAIHEM nonequilibrium chemistry package. We find that after 9 Gyr of evolution, the presence of a magnetic field leads to an overall hotter CGM, with cool gas in the center where magnetic pressure dominates. While the non-MHD run produces more cold clouds overall, we find similar Siiv/Oviand Nv/Oviratios between the MHD and non-MHD runs, which are both very different from their equilibrium values. The non-MHD halo develops cool, low angular momentum filaments above the central disk, in comparison to the MHD run that has more efficient angular momentummore »
3. ABSTRACT We investigate the impact of cosmic rays (CRs) on the circumgalactic medium (CGM) in FIRE-2 simulations, for ultra-faint dwarf through Milky Way (MW)-mass haloes hosting star-forming (SF) galaxies. Our CR treatment includes injection by supernovae, anisotropic streaming and diffusion along magnetic field lines, and collisional and streaming losses, with constant parallel diffusivity $\kappa \sim 3\times 10^{29}\, \mathrm{cm^2\ s^{-1}}$ chosen to match γ-ray observations. With this, CRs become more important at larger halo masses and lower redshifts, and dominate the pressure in the CGM in MW-mass haloes at z ≲ 1–2. The gas in these ‘CR-dominated’ haloes differs significantly from runs without CRs: the gas is primarily cool (a few ${\sim}10^{4}\,$ K), and the cool phase is volume-filling and has a thermal pressure below that needed for virial or local thermal pressure balance. Ionization of the ‘low’ and ‘mid’ ions in this diffuse cool gas is dominated by photoionization, with O vi columns ${\gtrsim}10^{14.5}\, \mathrm{cm^{-2}}$ at distances ${\gtrsim}150\, \mathrm{kpc}$. CR and thermal gas pressure are locally anticorrelated, maintaining total pressure balance, and the CGM gas density profile is determined by the balance of CR pressure gradients and gravity. Neglecting CRs, the same haloes are primarily warm/hot ($T\gtrsim 10^{5}\,$K) with thermal pressure balancing gravity,more »
4. ABSTRACT
The physics of magnetic fields (B) and cosmic rays (CRs) have recently been included in simulations of galaxy formation. However, significant uncertainties remain in how these components affect galaxy evolution. To understand their common observational tracers, we analyse the magnetic fields in a set of high-resolution, magnetohydrodynamic, cosmological simulations of Milky-Way-like galaxies from the FIRE-2 project. We compare mock observables of magnetic field tracers for simulations with and without CRs to observations of Zeeman splitting and rotation/dispersion measures. We find reasonable agreement between simulations and observations in both the neutral and the ionized interstellar medium (ISM). We find that the simulated galaxies with CRs show weaker ISM |B| fields on average compared to their magnetic-field-only counterparts. This is a manifestation of the effects of CRs in the diffuse, low density inner circumgalactic medium (CGM). We find that equipartition between magnetic and cosmic ray energy densities may be valid at large (> 1 kpc) scales for typical ISM densities of Milky-Way-like galaxies, but not in their haloes. Within the ISM, the magnetic fields in our simulated galaxies follow a power-law scaling with gas density. The scaling extends down to neutral hydrogen number densities < 300 cm−3, in contrast to observationally derived models,more »
5. ABSTRACT
Quasar absorption-line studies in the ultraviolet (UV) can uniquely probe the nature of the multiphase cool–warm (104 < T < 106 K) gas in and around galaxy clusters, promising to provide unprecedented insights into (1) interactions between the circumgalactic medium (CGM) associated with infalling galaxies and the hot (T > 106 K) X-ray emitting intracluster medium (ICM), (2) the stripping of metal-rich gas from the CGM, and (3) a multiphase structure of the ICM with a wide range of temperatures and metallicities. In this work, we present results from a high-resolution simulation of an $\sim 10^{14} \, \mathrm{M}_{\odot }$ galaxy cluster to study the physical properties and observable signatures of this cool–warm gas in galaxy clusters. We show that the ICM becomes increasingly multiphased at large radii, with the cool–warm gas becoming dominant in cluster outskirts. The diffuse cool–warm gas also exhibits a wider range of metallicity than the hot X-ray emitting gas. We make predictions for the covering fractions of key absorption-line tracers, both in the ICM and in the CGM of cluster galaxies, typically observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope (HST). We further extract synthetic spectra to demonstrate the feasibility of detecting and characterizingmore »
| 2023-02-07T23:50:10 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6060359477996826, "perplexity": 3415.433894959979}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500664.85/warc/CC-MAIN-20230207233330-20230208023330-00045.warc.gz"}
|
https://docs.nersc.gov/programming/high-level-environments/python/
|
# Python¶
Python is an interpreted general-purpose high-level programming language. You can use Anaconda Python on Cori through software environment modules. Do not use the system-provided Python /usr/bin/python.
## Python 2 is retiring on Jan 1, 2020¶
Are you still using Python 2?
Python 2 is retiring on Jan 1, 2020. Now is the time to update your code to Python 3. Python 2 will stop being maintained on January 1, 2020. It will still "work", but without active support, it will wither away. Python 3 is not backward-compatible with Python 2, so you must actively transition your code. Please see our dedicated page here for more information and reccomendations.
## Anaconda Python¶
Anaconda Python is a platform for large-scale data processing, predictive analytics, and scientific computing. It includes hundreds of open source packages and Intel MKL optimizations throughout the scientific Python stack. Anaconda provides the conda command-line tool for managing packages, but also works well with pip. The Anaconda distribution also exposes access to the Intel Distribution for Python.
Both Anaconda Python 2 and 3 are available. For example, to load the Python 3.7 Anaconda environment, type:
module load python/3.7-anaconda-2019.07
The default is python/2.7-anaconda-2019.07 so only module load python is necessary to use it. Python 2.7 will remain the default through the end of 2019 but you are encouraged to migrate to Python 3 before then.
When you load a Python module you are placed into its default Anaconda "root" environment. This may be sufficient for your needs. NERSC can install Anaconda packages into the root environment upon request subject to review of broad utility and maintainability. Contact us to find out about specific packages. In general we recommend users manage their own Python installations with "conda environments."
## Conda Environments¶
The conda tool lets you build your own custom Python installation through "environments." Conda environments replace and surpass virtualenv virtual environments in many ways. To create and start using a conda environment you can use conda create. Specify a name for the environment and at least one Python package to install. In particular you should specify which Python interpreter you want installed. Otherwise conda may make a decision that surprises you.
module load python/3.7-anaconda-2019.07
conda create -n myenv python=3 numpy
[installation outputs]
source activate myenv
Should I use source activate\deactivate or conda activate\deactivate?
You may have noticed messages like:
To activate this environment, use
$conda activate <environment> To deactivate an active environment, use$ conda deactivate
• Use source activate <environment> or source activate && conda activate <environment>
• Use conda deactivate instead of source deactivate
Long answer: Using conda activate <environment> will fail with a message to run conda init . At NERSC, this is not possible because conda init will try to modify the shell initialization script (.bashrc for bash), which is owned by a restricted user, not by you. Running source activate (no environment specified) will effectively emulate the functionality of conda init <shell>. Once, conda is activated, either by source activate && conda activate <environment> or source activate <environment>, it is then possible (and recommended) to use the modern conda deactivate to deactivate the conda environment.
Part of the issue is that conda does not provide a way for us to edit this configuration. The other part is how we have configured our own system. We are hoping that one or both of these issues can be resolved soon so we can switch to the more modern conda activate.
Before it installs anything conda create will show you what package management steps it will take and where the installation will go. You will be asked for confirmation before installation proceeds.
The Life You Save May Be Your Own
Make it a habit to actually review conda tool reports and not just blithely punch the "y" key to approve create/install/update actions. Verify the installation is going where you think it should. Make sure any proposed package downgrades are acceptable.
Once the environment is created you need to switch to it using source activate. After activation the name of the environment will appear in your prompt.
To leave an environment behind use:
source deactivate
If you use csh or tcsh you will not be able to use the source activate syntax. For csh users this is a shortcoming of the conda tool. There are workarounds available on the web that work to varying degrees. (We often find users are able to switch to /bin/bash without much difficulty, that is one solution.)
If you are a csh user and you do not need to install or manage packages once a conda environment has been provisioned, you can simply set PATH to point to the path of the Python interpreter in the environment.
## Installing Packages¶
You can find packages and install them into your own environments easily.
conda search scipy
[list of available versions of scipy]
conda install scipy
If conda search fails to identify your desired package it may still be installed via pip. Both conda and pip can be used in conda environments.
Use conda to install pip into your environment
To use pip in your own environment you may need to conda install pip. Verify whether you need to by typing "which pip" at the command line. If the path returned looks like /usr/common/software/python/.../bin/pip then do conda install pip.
If you consider pip a last resort you may want to search non-default channels for builds of the package you want. The syntax for that is a little different:
anaconda search -t conda <package-name>
[list of channels providing the package]
conda install -c <channel-name> <package-name>
Finally you can install packages "from source" and in some cases this is recommended. In particular any package that depends on the Cray programming environment should be installed this way. For Python this usually boils down to mpi4py and h5py with MPI-IO support.
## Running Scripts¶
Run serial Python scripts on a login node, or on a compute node in an interactive session (started via salloc) or batch job (submitted via sbatch) as you normally would in any Unix-like environment. On login nodes, please be mindful of resource consumption since those nodes are shared by many users at the same time.
Parallel Python scripts launched in an interactive (salloc) session or batch job (sbatch), such as those using MPI via the mpi4py module, must use srun to launch:
srun -n 64 python ./hello-world.py
## Collaborative Installations¶
Collaborations, projects, or experiments may wish to install a shareable, managed Python stack to /global/common/software independent of the NERSC modules. You are welcome to use the Anaconda installer script for this purpose. In fact you may want to consider the more "stripped-down" Miniconda installer as a starting point. That option allows you to start with only the bare essentials and build up. Be sure to select Linux version in either case! For instance:
https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
bash Miniconda3-latest-Linux-x86_64.sh -b \
-p /global/common/software/myproject/env
[installation messages]
source /global/common/software/myproject/env/bin/activate
conda install <only-what-my-project-needs>
You can customize the path with the -p argument. Ihe installation above would go to \$HOME/miniconda3 without it.
Attention
When using your own Anaconda/Miniconda installation be sure not to load any NERSC-provided Python modules. Also take care to consider the PYTHONSTARTUP environment variable which you may wish to unset altogether. It is mainly relevant to the system Python we advise against using.
Note that to activate the root environment, technically you should use the source shell command. Setting PATH to the root environment bin directory works but the source/conda tool does more than that.
| 2019-11-17T10:56:08 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.184181347489357, "perplexity": 4829.213868267408}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668910.63/warc/CC-MAIN-20191117091944-20191117115944-00139.warc.gz"}
|
http://dlmf.nist.gov/14.18
|
# §14.18 Sums
## §14.18(i) Expansion Theorem
For expansions of arbitrary functions in series of Legendre polynomials see §18.18(i), and for expansions of arbitrary functions in series of associated Legendre functions see Schäfke (1961b).
| 2013-12-06T10:40:59 |
{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8783954381942749, "perplexity": 4405.1694801640215}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-48/segments/1386163051248/warc/CC-MAIN-20131204131731-00027-ip-10-33-133-15.ec2.internal.warc.gz"}
|
https://conferences.lbl.gov/event/137/session/20/contribution/196
|
# CIPANP 2018 - Thirteenth Conference on the Intersections of Particle and Nuclear Physics
from 29 May 2018 to 3 June 2018
Hyatt Regency Indian Wells Conference Center
US/Pacific timezone
Home > Timetable > Session details > Contribution details
# Contribution Parallel
Hyatt Regency Indian Wells Conference Center - North Foyer | Joshua Tree Room
# Results from ANITA
## Speakers
• Dr. Cosmin DEACONU
## Abstract
The ANtarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload searches for Askaryan radio emission from ultra-high-energy ($>10^{18}$ eV) neutrinos interacting in Antarctic ice. ANITA is also sensitive to geomagnetic radio emission from extensive air showers. After a brief overview of the experiment, this talk will detail recently released results from the third flight of ANITA. Updates will also be provided on ongoing analysis of ANITA-IV and future plans. The most sensitive search from ANITA-III identified one neutrino candidate with an $\textit{a priori}$ background estimate of $0.7^{+0.5}_{-0.3}$. When combined with previous flights, ANITA sets the best limits on diffuse neutrino flux at energies above $\sim10^{19.5}$ eV. While the candidate is consistent with the pre-unblinding background estimate, a neutrino interpretation of the event remains plausible even after being subjected to post-unblinding examination. Additionally, ANITA-III searches identified nearly 30 extensive air shower candidates. One such event appears to correspond to an upward-going air shower similar to an event from ANITA-I. A tau neutrino could induce an upward-going air shower, but this interpretation is inconsistent with limits from other experiments and, due to the implied path length through the Earth, potentially in tension with the Standard Model's predicted neutrino-nucleon cross-section.
## E-mail
[email protected]
ANITA
| 2019-02-18T20:17:56 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.43556368350982666, "perplexity": 8663.638087243688}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-09/segments/1550247488374.18/warc/CC-MAIN-20190218200135-20190218222135-00632.warc.gz"}
|
https://par.nsf.gov/biblio/10346269
|
A broadband radio view of transient jet ejecta in the black hole candidate X-ray binary MAXI J1535–571
Abstract We present a broadband radio study of the transient jets ejected from the black hole candidate X-ray binary MAXI J1535–571, which underwent a prolonged outburst beginning on 2017 September 2. We monitored MAXI J1535–571 with the Murchison Widefield Array (MWA) at frequencies from 119 to 186 MHz over six epochs from 2017 September 20 to 2017 October 14. The source was quasi-simultaneously observed over the frequency range 0.84–19 GHz by UTMOST (the Upgraded Molonglo Observatory Synthesis Telescope) the Australian Square Kilometre Array Pathfinder (ASKAP), the Australia Telescope Compact Array (ATCA), and the Australian Long Baseline Array (LBA). Using the LBA observations from 2017 September 23, we measured the source size to be $34\pm1$ mas. During the brightest radio flare on 2017 September 21, the source was detected down to 119 MHz by the MWA, and the radio spectrum indicates a turnover between 250 and 500 MHz, which is most likely due to synchrotron self-absorption (SSA). By fitting the radio spectrum with a SSA model and using the LBA size measurement, we determined various physical parameters of the jet knot (identified in ATCA data), including the jet opening angle ( $\phi_{\rm op} = 4.5\pm1.2^{\circ}$ ) and the magnetic field strength more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10346269
Journal Name:
Publications of the Astronomical Society of Australia
Volume:
38
ISSN:
1323-3580
Weakly accreting black hole X-ray binaries launch compact radio jets that persist even in the quiescent spectral state, at X-ray luminosities ≲ 10−5 of the Eddington luminosity. However, radio continuum emission has been detected from only a few of these quiescent systems, and little is known about their radio variability. Jet variability can lead to misclassification of accreting compact objects in quiescence, and affects the detectability of black hole X-ray binaries in next-generation radio surveys. Here we present the results of a radio monitoring campaign of A0620 − 00, one of the best-studied and least-luminous known quiescent black hole X-ray binaries. We observed A0620 − 00 at 9.8 GHz using the Karl G Jansky Very Large Array on 31 epochs from 2017 to 2020, detecting the source $\sim 75{{\ \rm per\, cent}}$ of the time. We see significant variability over all time-scales sampled, and the observed flux densities follow a lognormal distribution with μ = 12.5 μJy and σ = 0.22 dex. In no epoch was A0620 − 00 as bright as in 2005 (51 ± 7 μJy), implying either that this original detection was obtained during an unusually bright flare, or that the system is fading in the radio over time. We presentmore »
4. Abstract We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster—the Fornax cluster—which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe’s Magnetism (POSSUM) covering a ${\sim}34$ square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ${\sim}25$ RMs per square degree from a 280-MHz band centred at 887 MHz, which is similar to expectations for forthcoming GHz-frequency ${\sim}3\pi$ -steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by $16.8\pm2.4$ rad m −2 within 1 $^\circ$ (360 kpc) projected distance to the cluster centre, which is 2–4 times larger than the spatial extent of the presently detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM and exists in a density regime that broadly matches expectations for moderately dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be amore »
| 2022-12-06T23:37:03 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5659334063529968, "perplexity": 3731.514565947592}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446711121.31/warc/CC-MAIN-20221206225143-20221207015143-00540.warc.gz"}
|
https://lammps.sandia.gov/doc/pair_agni.html
|
# pair_style agni/omp command
## Syntax
pair_style agni
## Examples
pair_style agni pair_coeff * * Al.agni Al
## Description
Style agni style computes the many-body vectorial force components for an atom as
u labels the individual components, i.e. x, y or z, and V is the corresponding atomic fingerprint. d is the Euclidean distance between any two atomic fingerprints. A total of N_t reference atomic environments are considered to construct the force field file. alpha_t and l are the weight coefficients and length scale parameter of the non-linear regression model.
The method implements the recently proposed machine learning access to atomic forces as discussed extensively in the following publications - (Botu1) and (Botu2). The premise of the method is to map the atomic environment numerically into a fingerprint, and use machine learning methods to create a mapping to the vectorial atomic forces.
Only a single pair_coeff command is used with the agni style which specifies an AGNI potential file containing the parameters of the force field for the needed elements. These are mapped to LAMMPS atom types by specifying N additional arguments after the filename in the pair_coeff command, where N is the number of LAMMPS atom types:
• filename
• N element names = mapping of AGNI elements to atom types
See the pair_coeff doc page for alternate ways to specify the path for the force field file.
An AGNI force field is fully specified by the filename which contains the parameters of the force field, i.e., the reference training environments used to construct the machine learning force field. Example force field and input files are provided in the examples/USER/misc/agni directory.
Styles with omp suffix is functionally the same as the corresponding style without the suffix. They have been optimized to run faster, depending on your available hardware, as discussed on the Speed packages doc page. The accelerated style takes the same arguments and should produce the same results, except for round-off and precision issues.
The accelerated style is part of the USER-OMP. They are only enabled if LAMMPS was built with those packages. See the Build package doc page for more info.
You can specify the accelerated style explicitly in your input script by including their suffix, or you can use the -suffix command-line switch when you invoke LAMMPS, or you can use the suffix command in your input script.
See the Speed packages doc page for more instructions on how to use the accelerated styles effectively.
Mixing, shift, table, tail correction, restart, rRESPA info:
This pair style does not support the pair_modify shift, table, and tail options.
This pair style does not write its information to binary restart files, since it is stored in potential files. Thus, you need to re-specify the pair_style and pair_coeff commands in an input script that reads a restart file.
This pair style can only be used via the pair keyword of the run_style respa command. It does not support the inner, middle, outer keywords.
## Restrictions
Currently, only elemental systems are implemented. Also, the method only provides access to the forces and not energies or stresses. However, one can access the energy via thermodynamic integration of the forces as discussed in (Botu3). This pair style is part of the USER-MISC package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.
The AGNI force field files provided with LAMMPS (see the potentials directory) are parameterized for metal units. You can use the AGNI potential with any LAMMPS units, but you would need to create your own AGNI potential file with coefficients listed in the appropriate units if your simulation doesn’t use “metal” units.
| 2019-11-19T09:06:48 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5485140681266785, "perplexity": 2737.4000925067703}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496670036.23/warc/CC-MAIN-20191119070311-20191119094311-00183.warc.gz"}
|
https://pdglive.lbl.gov/ParticleGroup.action?init=0&node=BXXX035
|
${{\mathit \Omega}}$ BARYONS ($\mathit S$ = $-3$, $\mathit I$ = $\mathit{0}$)
${{\mathit \Omega}^{-}}$ = ${\mathit {\mathit s}}$ ${\mathit {\mathit s}}$ ${\mathit {\mathit s}}$
| 2022-12-07T20:07:00 |
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6875972747802734, "perplexity": 407.24623915357785}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446711218.21/warc/CC-MAIN-20221207185519-20221207215519-00440.warc.gz"}
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.