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September 26, 2018
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https://www.sciencedaily.com/releases/2018/09/180926110943.htm
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More persistent weather patterns in US linked to Arctic warming
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Persistent weather conditions, including dry and wet spells, generally have increased in the United States, perhaps due to rapid Arctic warming, according to a Rutgers-led study.
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Persistent weather conditions can lead to weather extremes such as drought, heat waves, prolonged cold and storms that can cost millions of dollars in damage and disrupt societies and ecosystems, the study says.Scientists at Rutgers University-New Brunswick and the University of Wisconsin-Madison examined daily precipitation data at 17 stations across the U.S., along with large upper-level circulation patterns over the eastern Pacific Ocean and North America.Overall, dry and wet spells lasting four or more days occurred more frequently in recent decades, according to the study published online today in In recent decades, the Arctic has been warming at least twice as fast as the global average temperature, the study notes. The persistence of warm Arctic patterns has also increased, suggesting that long-duration weather conditions will occur more often as rapid Arctic warming continues, said lead author Jennifer Francis, a research professor in Rutgers' Department of Marine and Coastal Sciences."While we cannot say for sure that Arctic warming is the cause, we found that large-scale patterns with Arctic warming are becoming more frequent, and the frequency of long-duration weather conditions increases most for those patterns," said Francis, who works in the School of Environmental and Biological Sciences.The results suggest that as the Arctic continues to warm and melt, it's likely that long-duration events will continue to occur more often, meaning that weather patterns -- heat waves, droughts, cold spells and stormy conditions -- will likely become more persistent, she said."When these conditions last a long time, they can become extreme events, as we've seen so often in recent years," she said. "Knowing which types of events will occur more often in which regions and under what background conditions -- such as certain ocean temperature patterns -- will help decision-makers plan for the future in terms of infrastructure improvements, agricultural practices, emergency preparedness and managed retreat from hazardous areas."Future research will expand the analysis to other regions of the Northern Hemisphere, develop new metrics to find causal connections, and analyze projections to assess future risks from extreme weather events linked to persistent patterns, she said.
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September 24, 2018
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https://www.sciencedaily.com/releases/2018/09/180924144028.htm
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How will climate change stress the power grid? Hint: Look at dew point temperatures
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A new study suggests the power industry is underestimating how climate change could affect the long-term demand for electricity in the United States.
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The research, published today in the journal It describes the limitations of prediction models used by electricity providers and regulators for medium- and long-term energy forecasting. And it outlines a new model that includes key climate predictors -- mean dew point temperature and extreme maximum temperature -- that researchers say present a more accurate view of how climate change will alter future electricity demands."Existing energy demand models haven't kept pace with our increasing knowledge of how the climate is changing," says the study's lead author Sayanti Mukherjee, PhD, assistant professor of industrial and systems engineering in UB's School of Engineering and Applied Sciences. "This is troublesome because it could lead to supply inadequacy risks that cause more power outages, which can affect everything from national security and the digital economy to public health and the environment.""The availability of public data in the energy sector, combined with advances in algorithmic modeling, has enabled us to go beyond existing approaches that often exhibit poor predictive performance. As a result, we're able to better characterize the nexus between energy demand and climate change, and assess future supply inadequacy risks," says co-author Roshanak Nateghi, PhD, assistant professor of industrial engineering and environmental and ecological engineering at Purdue.The overwhelming majority of climate scientists predict global temperatures will rise throughout 21st century. This is expected to increase the demand for electricity as more people turn to air conditioners to keep cool.One of the most common energy modeling platforms used to predict future electricity demand -- MARKAL, named after MARKet and ALlocation -- does not consider climate variability.Another common energy-economic model, the National Energy Modeling System, or NEMS, does consider the climate. However, it's limited to heating and cooling degree days. A heating degree day is defined as a day when the average temperature is above 65 degrees Fahrenheit (18 degrees Celsius). A cooling degree day is when the average temperature is below 65 degrees.While there are different ways to measure heating and cooling degree days, they are most often calculated by adding the day's high temperature to the day's low temperature, and then dividing the sum by two. For example, a high of 76 degrees and a low of 60 degrees results in an average temperature of 68 degrees.The trouble with this approach, Mukherjee says, is that it doesn't consider time. For example, it could be 76 degrees for 23 hours and 60 degrees for one hour -- yet the average temperature that day would still be recorded as 68 degrees."Moreover, choice of the accurate balance point temperature is highly contentious, and there is no consensus from the research community of how to best select it," says Mukherjee.To address these limitations, she and Nateghi studied more than a dozen weather measurements. They found that the mean dew point temperature -- the temperature at which air is saturated with water vapor -- is the best predictor of increased energy demand. The next best predictor is the extreme maximum temperature for a month, they say.The researchers combined these climate predictors with three other categories -- the sector (residential, commercial and industrial) consuming the energy, weather data and socioeconomic data -- to create their model.They applied the model to the state of Ohio and found that the residential sector is most sensitive to climate variabilities. With a moderate rise in dew point temperature, electricity demand could increase up to 20 percent. The prediction jumps to 40 percent with a severe rise.By comparison, the Public Utility Commission of Ohio (PUCO), which does not consider climate change in its models, predicts residential demand increases of less than 4 percent up to 2033.It's similar in the commercial sector, where the researchers say demand could increase to 14 percent. Again, PUCO's projections are lower, 3.2 percent. The industrial sector is less sensitive to temperature variability, however, researchers say the demand could still exceed projections.During the winter months, variations between the models is less significant. That is due, in part, to the relatively low percentage (22.6 percent) of Ohio residents who heat their homes via electricity.While the study is limited to Ohio, researchers say the model can be applied to other states. To communicate results, the researchers used heat maps, which provide an immediate visual summary of the data represented by colors. The idea, they say, is to better inform decision makers with accurate and easy to understand information.
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September 24, 2018
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https://www.sciencedaily.com/releases/2018/09/180924091654.htm
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National parks bear the brunt of climate change
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Human-caused climate change has exposed U.S. national parks to conditions hotter and drier than the rest of the nation, says a new UC Berkeley and University of Wisconsin-Madison study that quantifies for the first time the magnitude of climate change on all 417 parks in the system.
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Without action to limit greenhouse gas emissions, many small mammals and plants may be brought to the brink of extinction by the end of the century, the study shows.The analysis reveals that over the past century, average temperatures in national parks increased at twice the rate as the rest of the nation and yearly rainfall decreased more in national parks than in other regions of the country.At the current rate of emissions, the team projects that temperatures in the most exposed national parks could soar by as much as 9 degrees Celsius or 16 degrees Fahrenheit by 2100. This rate of change is faster than many small mammals and plants can migrate or "disperse" to more hospitable climates."Human-caused climate change is already increasing the area burned by wildfires across the western U.S., melting glaciers in Glacier Bay National Park and shifting vegetation to higher elevations in Yosemite National Park," said Patrick Gonzalez, associate adjunct professor in the Department of Environmental Science, Policy and Management at UC Berkeley and a lead author for the Intergovernmental Panel on Climate Change (IPCC) report, a summary of the most up-to-date scientific knowledge of climate change."The good news is that, if we reduce our emissions from cars, power plants, deforestation, and other human activities and meet the Paris Agreement goal, we can keep the temperature increase in national parks to one-third of what it would be without any emissions reductions," Gonzalez said.The locations of these unique ecosystems are what make them particularly exposed to climate change, Gonzalez said. Many national parks are found in deserts, high mountains or in the Arctic region of Alaska, climates that are known to be the hardest hit by global warming."National parks aren't a random sample -- they are remarkable places and many happen to be in extreme environments," Gonzalez said. "Many are in places that are inherently more exposed to human-caused climate change."The analysis, which includes all 50 U.S. states, the District of Columbia and four territories in the Caribbean and Pacific, appears Sept. 24 in the journal Weather stations scattered throughout the U.S. have been gathering monthly data on temperature and rainfall dating back to 1895. Using this data, climate researchers have created maps of the average annual temperature and rainfall totals at points approximately 800 meters over much of the United States.In this study, the team used these maps to calculate historical temperature and rainfall trends within the parks and over the U.S. as a whole. They found that the temperature in national parks increased by a little over 1 degree Celsius from 1895 to 2010, roughly double the warming experienced by the rest of the country. Yearly rainfall totals decreased over 12 percent of national park land, compared to 3 percent of land in the United States. Alaska and its national parks saw the most dramatic increases in temperature, while rainfall decreased most in Hawaii.The team mapped projected future changes in temperature and precipitation for climate models representing each of four climate change scenarios developed by the IPCC. These four "storylines of the future," as scientists call them, include a scenario where no action has been taken to reduce emissions, one that is consistent with the Paris Agreement and two that are intermediate.Under the most extreme climate change scenario, the average temperature of all the national parks together is projected to increase between 5 and 7 degrees Celsius. Sticking to the Paris Agreement could limit this rise to between 1 and 3 degrees Celsius. Under both scenarios, temperature could increase most in Alaska and its national parks, while rainfall could decrease most in the Virgin Islands and the southwestern U.S.To analyze future projections, the team also "downscaled" the climate models, making more detailed maps of future climate trends within the parks. Whereas the climate models themselves have coarse resolutions of approximately 100 to 400 kilometers, the downscaled data have resolutions of 100 to 800 meters over most of the country.These maps can help park service employees plan for future vulnerabilities to climate change of endangered species and other park resources by developing measures to protect against wildfires and controlling invasive species."The park service is already integrating this climate change information into their planning and resource management," said Fuyao Wang, a research associate at the University of Wisconsin-Madison."It is important to note that even if we really do a strong mitigation of greenhouse gases, the national park system is still expected to see a 2 degree temperature change," said John Williams, a professor of geography at the University of Wisconsin-Madison. "At this point, it is likely that the glaciers in Glacier National park will ultimately disappear, and what is Glacier National park if it doesn't have glaciers anymore? So I think this adds weight to the importance of reducing our future levels of climate change and also extends the National Park Service mission to both adapt to these changes and educate all of us about these changes."
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September 21, 2018
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https://www.sciencedaily.com/releases/2018/09/180921092427.htm
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Extra Arctic observations can improve predictability of tropical cyclones
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Japanese scientists and their international partners have found that additional weather observations in the Arctic can help predict the track and intensity of tropical and mid-latitude cyclones more accurately, improving weather forecasting of extreme weather events.
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Their findings were published on August 14th in Upper-level observations such as radiosondes in the Arctic can help to forecast mid-latitude extreme events. Impacts of the Arctic observations can transfer via the tropospheric polar vortex, which is massive low-pressure air mass over the Arctic or Antarctic regions at about 10-km altitude. The tropospheric polar vortex sometimes extends toward mid-latitudes accompanied with meandering of mid-latitude westerly jets. This extension can occur even in summer: in August-September 2016, the meandering and extension were relatively active among the recent years. Thus, the impacts of the Arctic radiosonde observations could influence the mid-latitude extremes, the courses of three tropical cyclones approaching to Japan or Northern U.S. and Greenland, since the impacts transferred trough the extended tropospheric polar vortex.Having a clearer understanding of these influences can help us better predict, track and prepare for extreme weather events such as cyclones. Currently, meteorological observations are conducted by radiosonde, a weather instrument that records meteorological data, typically released into the atmosphere with a weather balloon. However, due to hostile conditions experienced in the Arctic and the limited reach of the low pressure system, the number and frequency of these observations are limited. Consequently, there are gaps in the data that result in weather forecasts being less accurate than what they could and should be, potentially putting peoples' lives at risk."Extreme weather events have been frequently observed in all seasons all over the world," said lead-author Kazutoshi Sato, an assistant professor at the Kitami Institute of Technology and previous member of the National Institute of Polar Research (NIPR) in Japan. "Hurricanes and typhoons are one of the most influential phenomena for human life. Precise weather forecast is critical to enable communities to adequately prepare for weather disasters," he added.For the study, the researchers performed weather forecast experiments for three tropical cyclones that occurred over the North Atlantic and North Pacific during 2016, to determine whether additional observations could help predict their paths and intensity more accurately. To supplement existing weather data observations, additional observations were conducted using weather balloons released from ship- and land-based weather stations based in the Arctic. The data were analyzed using a data assimilation system developed in Japan Agency for Marine-Earth Science and Technology, which can produce reanalysis datasets by "mixing" (assimilating) observations into global atmospheric conditions: the system was indispensable for the forecast experiments. The additional observations improved the predictability of the cyclones, allowing the scientists to track the paths of the cyclones as well as forecast their intensity more accurately."This study demonstrated the usefulness of additional Arctic observations for mid-latitude numerical weather forecasts for tropical cyclones," said co-author Jun Inoue, an associate professor at NIPR -- one of four Research Organization of Information Systems (RIOS) institutes.Additional radiosonde observations and its evaluation on weather forecasts were conducted privately by scientists, said Inoue, adding that while "this 'quiet revolution of forecasting' is, of course, beneficial for end users," it is difficult to implement sustainable Arctic observations due to the harsh environment in the Arctic. "Now, stakeholders and decision-makers can start to consider the future Arctic observing network to reduce the socio-economical risks associated with extreme weather events," said Inoue. "Our study contributes to providing such an opportunity.""From July to September 2018 additional 3,000 radiosondes have been launched from the Arctic region to reduce the uncertainty of forecasts in the Arctic and beyond as part of the Year of Polar Prediction (YOPP) project," said Inoue. "Many meteorological centers will evaluate their impact on the atmospheric circulation in the Northern Hemisphere. Understanding the predictability of the atmosphere, ocean, and sea ice will progress with advances in the Arctic observing network and numerical model development," he said.With extreme weather events becoming more frequent and more intense due to climate and ocean warming, being able to more accurately predict and track tropical cyclones can help communities be more prepared for potentially devastating storms, which in turn can help save lives.Other authors of this study are Akira Yamazaki of Japan Agency for Marine-Earth Science and Technology, Joo-Hong Kim of Korea Polar Research Institute, Alexander Makshtas, Vasilli Kustov of Arctic and Antarctic Research Institute, Marion Maturilli and Klaus Dethloff of Alfred Wegener Institute.
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September 20, 2018
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https://www.sciencedaily.com/releases/2018/09/180920160845.htm
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NASA balloon mission captures electric blue clouds
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On the cusp of our atmosphere live a thin group of seasonal electric blue clouds. Forming 50 miles above the poles in summer, these clouds are known as noctilucent clouds or polar mesospheric clouds -- PMCs. A recent NASA long-duration balloon mission observed these clouds over the course of five days at their home in the mesosphere. The resulting photos, which scientists have just begun to analyze, will help us better understand turbulence in the atmosphere, as well as in oceans, lakes and other planetary atmospheres, and may even improve weather forecasting.
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On July 8, 2018, NASA's PMC Turbo mission launched a giant balloon to study PMCs at a height of 50 miles above the surface. For five days, the balloon floated through the stratosphere from its launch at Esrange, Sweden, across the Arctic to Western Nunavut, Canada. During its flight, cameras aboard the balloon captured 6 million high-resolution images filling up 120 terabytes of data storage -- most of which included a variety of PMC displays, revealing the processes leading to turbulence. Scientists are now beginning to go through the images and the first look has been promising."From what we've seen so far, we expect to have a really spectacular dataset from this mission," said Dave Fritts, principal investigator of the PMC Turbo mission at Global Atmospheric Technologies and Sciences in Boulder, Colorado. "Our cameras were likely able to capture some really interesting events and we hope will provide new insights into these complex dynamics."Noctilucent clouds coalesce as ice crystals on tiny meteor remnants in the upper atmosphere. The results make brilliant blue rippling clouds that are visible just after the Sun sets in polar regions during the summer. These clouds are affected by what's known as atmospheric gravity waves -- caused by the convecting and uplifting of air masses, such as when air is pushed up by mountain ranges. The waves play major roles in transferring energy from the lower atmosphere to the mesosphere."This is the first time we've been able to visualize the flow of energy from larger gravity waves to smaller flow instabilities and turbulence in the upper atmosphere," Fritts said. "At these altitudes you can literally see the gravity waves breaking -- like ocean waves on the beach -- and cascading to turbulence."The PMC Turbo balloon payload was equipped with seven specially designed imaging systems to observe the clouds. Each included a high-resolution camera, a computer control and communications system, and 32 terabytes of data storage. The seven imaging systems were arranged to create a mosaic of wide views extending one hundred miles across, with each narrow views able to image turbulence features as small as 20 yards wide. For the first time, a lidar -- or laser radar -- measured the precise altitudes of the PMCs as well as the temperature fluctuations of the gravity waves above and below the PMCs."We know the 2D wave structure from the images, but in order to fully describe the waves we need to measure the third dimension as well," said Bernd Kaifler, the researcher at the German Aerospace Center, in Wessling, Germany, who designed the balloon's lidar experiment. "From the lidar measurements, we can infer the vertical structure of the waves, thus providing important data which would have not been available from the imaging experiment alone."Learning about the causes and effects of turbulence will help scientists understand not only the structure and variability of the upper atmosphere, but other areas as well. Turbulence occurs in fluids across the universe and the results will help scientists better model it in all systems. Ultimately, the results will even help improve weather forecast models.Understanding a wide range of processes in near-Earth space -- including how they interact with Earth's atmosphere and weather -- is a key part of NASA's heliophysics research, which employs a full squad of satellites and sub-orbital instruments to observe different phenomena from different perspectives. NASA also studies noctilucent clouds with the Aeronomy of Ice in the Mesosphere, or AIM, spacecraft, which launched in 2007 into a low-Earth orbit. AIM tracks large scale features in the clouds across a global scale, but can only resolve features a couple miles across. PMC Turbo helps fill in the details, explaining what happens at smaller scales where turbulence occurs.The PMC Turbo payload was successfully recovered from its landing site in the Canadian Arctic and the recovered instruments are expected to contribute to future missions, including one anticipated to fly next December over Antarctica.
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September 19, 2018
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https://www.sciencedaily.com/releases/2018/09/180919133028.htm
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Diverse forests are stronger against drought
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Diversity is strength, even among forests. In a paper published in
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Surprisingly, says Anderegg, a forest's hydraulic diversity is the predominant predictor of how well it can handle a drought."We expected that hydraulic traits should matter," he says, "but we were surprised that other traits that a lot of the scientific community have focused on weren't very explanatory or predictive at all."Anderegg is a veteran researcher of the impacts of droughts on trees, with particular attention to the time it takes for forests to recover from drought. Along with others in his field, he's also looked at the impact of hydraulic traits on individual tree species' survival chances in a drought. Hydraulic traits are connected to the way a tree moves water throughout the organism -- and how much drought stress they can take before that system starts breaking down.But droughts, when they strike, don't go after individual trees -- they affect entire ecosystems."What's different about this study is it's now looking at the whole forest," Anderegg says.Anderegg and his colleagues, including collaborators from Stanford University, Princeton University and the University of California, Davis, compiled data from 40 forest sites around the world. The sites are equipped with instruments called flux towers that measure the flows of carbon, water and energy from a forest. They're also equipped with environmental sensors, including soil moisture sensors, to produce a picture of how much water is moving into and out of the site.They coupled that data with what was known about the tree species present at each site, and the known hydraulic traits associated with those species. Non-hydraulic traits would be things like wood density or leaf area divided by leaf mass. But hydraulic traits include the hydraulic safety margin, the difference between the amount of water movement the tree allows during dry conditions and the absolute minimum water amount -- the point at which the tree's hydraulics start to shut down.Forests with a greater diversity of hydraulic traits in its tree species showed less of a dip in forest function (measured by fluxes of water and energy and soil moisture) than less-diverse forests. Satellite data of temperate forests worldwide confirmed their findings -- droughts just don't have the same effect on hydraulically diverse forests as on others."The species present and the hydraulic traits they have seem most important for predicting resilience to drought at an ecosystem scale," Anderegg says.So, what does a forest with hydraulic diversity look like? First, consider the opposite -- an ecosystem with only one kind of tree. Picture, for example, a Christmas tree farm. Each tree is the exact same species. Diversity doesn't get any lower than that.But a diverse forest, Anderegg says, "will have many different types of trees -- conifer and angiosperm, drought tolerant and intolerant wood, and maybe different rooting depths. It's going to involve some diversity in water source. These things are hard to study and measure directly."The team sees several future avenues for continuing this research."We want to understand what's the detailed physiology behind this resilience," Anderegg says. "What are the specific traits, either of different species or different populations, that give you resilience to future climate?"The researchers didn't look specifically at the connection between hydraulic traits, drought, and fire conditions, but a summer of the Western US on fire and the resultant smoke spreading across the country begs the question."More diversity in a landscape is going to help a forest be more resilient to fire," Anderegg says. The same climate conditions that underlie droughts -- early snowmelt and hot summertime temperatures, for example -- also underlie hazardous fire seasons."It dries out the fuel in the grounds," Anderegg says, "and creates supercharged fire weather."So what can forest managers do to improve diversity and resilience? Opportunities may come following traumas to the ecosystem such as logging or wildfire. "After we log a forest or a fire comes through," Anderegg says, "we sometimes think about planting a single species. We should be thinking about the best mixes of multiple species for resilience."
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September 18, 2018
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https://www.sciencedaily.com/releases/2018/09/180918110844.htm
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A key to climate stabilization could be buried deep in the mud
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Earth's peatland soils store a lot of carbon -- about as much as currently flows freely through the atmosphere as carbon dioxide. As global temperatures rise, scientists worry that the planet's grip on these carbon reservoirs could weaken, unleashing a "carbon bomb" that could further destabilize Earth's climate systems.
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But a new study led by Florida State University offers some hope that Earth's carbon reservoirs might not be quite as vulnerable as experts predict. In a global survey of peatlands -- areas defined by soil-like, partially decomposed organic matter -- researchers found signs that these carbon-rich environments could show some level of long-term resilience even as temperatures continue to climb."There's a lot of concern about losing these carbon reservoirs, but what this study suggests is that they are more stable than we initially thought," said Jeff Chanton, the Robert O. Lawton Distinguished Professor of Oceanography. "This mutes the carbon bomb hypothesis. It's good news."The findings were published in the journal Peat forms most frequently in the North, where cooler climes prevent organic matter from fully decomposing. But peatlands can also be found in the tropics, where warm weather facilitates rapid decomposition.This puzzled a team of researchers from FSU's Departments of Chemistry and Biochemistry and Earth, Ocean and Atmospheric Science. If tropical peatlands can successfully withstand equatorial temperatures, they asked, might northern peatlands also have the capacity to stabilize in warmer conditions?To investigate, the team collected peat samples from a globally representative selection of far-flung sites -- subarctic Swedish mires, temperate North Carolina bogs and tropical Bornean peat swamps to name a few. They then used advanced spectroscopy tools to investigate the unique chemical profiles of their samples.The team quickly identified significant chemical differences between peat sourced from higher and lower latitudes."Peat from warm climates had lower concentrations of carbohydrates and higher concentrations of aromatics compared to peat from colder climates," said former FSU postdoctoral researcher Suzanne Hodgkins, who led the study.Cold-climate peat, with its higher carbohydrate concentration, is considered by scientists to be more labile, or more easily degradable. As temperatures increase, the carbohydrates in the peat decompose and carbon dioxide is emitted.Warm-climate peat sampled from lower latitudes, on the other hand, was found to be largely depleted of carbohydrates. Instead, these samples contained high levels of aromatics -- stable chemical compounds left behind by decomposed plant matter.As temperatures rise at higher latitudes, northern peatlands will burn off their surface store of carbohydrates, releasing carbon dioxide into the atmosphere. The key to what happens next lies in the chemistry of the peat buried deep below the Earth, said Hodgkins, now a postdoctoral researcher at Ohio State University."The long-term stability of northern peat in the face of warming depends on whether it can develop a chemistry similar to tropical peats," she said "Initially, northern peat will likely decompose and release carbon into the atmosphere, but eventually this decomposition will reduce the abundance of carbohydrates relative to aromatics. This change in chemistry could stabilize the remaining peat against further decomposition."If, after the initial carbohydrate burn, northern peatlands come to more closely resemble their southern counterparts -- which have endured in warm weather for millennia -- then their aromatic-dominant chemistry could act as a bulwark against further decomposition and carbon dioxide release."Evidence from the study suggests that northern peatlands may develop many of the same compositional features as southern peatlands, mitigating to some extent the potential for substantial carbon losses to the atmosphere," said retired Professor of Analytical and Environmental Chemistry Bill Cooper, who helped direct the study.This mitigation is contingent on the rate of carbohydrate decomposition and the ways northern plant ecology adapts to warmer temperatures, but it could play a major role in preventing considerable amounts of carbon dioxide from reaching an already-warming atmosphere.However, while stable peatlands may help avert worst-case scenarios and temper the dreaded carbon bomb, researchers said these kind of ecological restraints on warming are not enough to reverse global climate trends."All of these natural processes pale in comparison to the rate at which human beings are releasing fossil fuel CO
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September 17, 2018
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https://www.sciencedaily.com/releases/2018/09/180917135942.htm
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More than 4 billion birds stream overhead during fall migration
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Using cloud computing and data from 143 weather radar stations across the continental United States, Cornell Lab of Ornithology researchers can now estimate how many birds migrate through the U.S. and the toll that winter and these nocturnal journeys take. Their findings are published in
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"We've discovered that each autumn, an average of 4 billion birds move south from Canada into the U.S. At the same time, another 4.7 billion birds leave the U.S. over the southern border, heading to the tropics," notes lead author Adriaan Dokter, an Edward W. Rose postdoctoral fellow at the Cornell Lab. "In the spring, 3.5 billion birds cross back into the U.S. from points south, and 2.6 billion birds return to Canada across the northern U.S. border."In other words, fewer birds return to their breeding grounds after going through fall migration and spending months on their wintering grounds. But the researchers were surprised to find that the migrants arriving across the U.S. southern border had an average return rate of 76 percent during the 5 years of the study (2013 to 2017) and the birds wintering in the U.S. had only an average return rate of 64 percent."Contrary to popular thought, birds wintering in the tropics survive the winter better than birds wintering in the U.S.," says Andrew Farnsworth, co-author of the study and leader of the Cornell Lab's aeroecology program. "That's despite the fact that tropical wintering birds migrate three to four times farther than the birds staying in the U.S."To reach these numbers, the researchers developed complicated algorithms to measure differences in biomass picked up by weather radar -- in this case, the total mass of organisms in a given area, minus insects and weather. Migrants crossing the northern border -- such as many sparrows, American Robins, and Dark-eyed Juncos -- have shorter migrations from breeding grounds in Canada to wintering grounds in the U.S.Measurements from the southern border captured data on migrants that breed in the U.S. and spend their winters in places such as Central or South America, such as most warblers, orioles, and tanagers. One explanation for the higher mortality among birds wintering in the U.S. may be the number of hazards they face."All birds need suitable habitats with enough resources to get them through the winter," notes Ken Rosenberg, co-author and conservation scientist at the Cornell Lab. "Birds wintering in the U.S. may have more habitat disturbances and more buildings to crash into, and they might not be adapted for that."Another reason for the disparity in migration return rates between short and long-distance migrants may have to do with breeding strategy. Birds wintering in the U.S. have high reproduction rates to offset higher mortality. Tropical wintering species have fewer offspring, but more adults survive through the winter and reproduce the following spring, despite their longer migrations. But it's a strategy that may backfire without conservation efforts in the tropics."Longer distance migrants seem to be gambling on having high survival in the tropics, and they're therefore more sensitive to what happens to their wintering grounds," says Dokter. "Even a small decrease in survival due to changes in their tropical habitats might cause a precipitous decline."
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Weather
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September 13, 2018
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https://www.sciencedaily.com/releases/2018/09/180913142002.htm
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Weather forecasting sheds light on where and when birds will fly
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Using a combination of AI and weather forecasting can help scientists to predict the movements of millions of birds and support their conservation goals, according to new Oxford University research.
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Conducted in collaboration with Cornell University, the study -- published in the journal September is the peak of autumn bird migration, and billions of birds are winging their way south in dramatic pulses. In this study, the researchers reviewed 23 years of spring bird migration across the United States using 143 weather radars, highly sensitive sensors that scientists can use to monitor bird movements. They filtered out precipitation and trained a machine learning model to associate atmospheric conditions with levels of bird migration countrywide. Eighty percent of variation in bird migration intensity was explained by the model.Benjamin Van Doren, a doctoral student at the University of Oxford and a Cornell University graduate, said: "Most of our songbirds migrate at night, and they pay close attention to the weather. Our model converts weather forecasts into bird migration forecasts for the continental United States."Completing the annual migration requires a lot of stamina and using forecasting helps scientists to reduce human-made threats to migratory birds, such as being disorientated by city lights or crashing into tall buildings and power lines that could hinder their journey. Not finding a suitable habitat to stop and recharge at along the way, could result in the birds not finishing their trip on time, or arriving in an unfit state to breed."The capacity to forecast where and when birds are likely to be flying is instrumental for conservation goals," says co-author Kyle Horton, a Rose Postdoctoral Fellow at the Cornell Lab.In addition to predicting pulses of intense migration, Van Doren and Horton also used the model to estimate nightly migratory movements across the entire country. During peak migration in early May, they say often more than 420 million birds pass overhead each night."We used 12 variables to model the distribution of migratory birds across the continent," explains Van Doren. "Temperature was the most important variable. Migration intensity was greatest on warm nights, probably because warm temperatures generally bring favorable winds and the emergence of leaves and insects."The first migration forecast maps based on this research were released to the public earlier this year on the Cornell Lab's BirdCast website ("Radars have been illuminating the movement of birds for nearly 75 years -- there are still integral discoveries to be made,' notes Horton. 'With migration coming into full swing, we're excited to deliver autumn forecasts for the first time."
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Weather
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September 13, 2018
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https://www.sciencedaily.com/releases/2018/09/180913113954.htm
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Climate-induced soil changes may cause more erosion and flash flooding
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The earth beneath our feet isn't usually the first thing that comes to mind when people think about the impacts of climate change. However, a study by a UC Riverside-led team of researchers predicts a climate-induced reduction in large soil pores, which may intensify the water cycle and contribute to more flash flooding and soil erosion by the end of the 21st century.
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In a paper published Sept. 5 in "It is important to predict the response of macroporosity to climate change because of its role in the water cycle, and ultimately in water scarcity, food security, human health and loss of biodiversity," said Daniel Hirmas, an associate professor in the Department of Environmental Sciences and lead author on the study.Using a large database of soils collected over 50 years from across the continental U.S. combined with atmospheric data from a network of weather stations, the researchers examined changes in macroporosity across a rainfall, temperature, and humidity gradient. They found macropores were more likely to develop in drier climates than humid climates, and that climate-related changes in macroporosity occur over shorter timescales than previously thought.The researchers then used climate projections for the end of the 21st Century to predict that increasing humidity by 2080-2100 will reduce soil macroporosity in most regions of the U.S. (with the exception of the southern coastal plain, which comprises Alabama and Louisiana).he consequences could be less infiltration of water into the ground, more surface runoff and erosion, and more flash flooding."This is the first study to show that the development of macropores is influenced by climate at short timescales and it reinforces the hypothesis that climate change will probably intensify the water cycle," Hirmas said. "Our results suggest that macroporosity should be incorporated into global climate models to better understand the water cycle, anticipate changes, and prepare for the future."The title of the paper is "Climate-induced changes in continental-scale soil macroporosity may intensify water cycle." In addition to Hirmas, authors include Daniel Giménez from Rutgers University; Attila Nemes from the Norwegian Institute of Bioeconomy Research (NIBIO); Ruth Kerry from Brigham Young University; and Nathaniel A. Brunsell and Cassandra J. Wilson from the University of Kansas. The work was funded by the United States Department of Agriculture's Agriculture and Food Research Initiative (USDA-AFRI) and NIBIO.
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September 12, 2018
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https://www.sciencedaily.com/releases/2018/09/180912132702.htm
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Fire weather prediction improving
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The weather plays a significant role in how a wildfire grows, how fast it spreads, and how dangerous it can become for firefighters, but few tools exist to help fire managers anticipate days when weather conditions will have the greatest potential to make wildfire erratic or especially dangerous. The USDA Forest Service is expanding the options with the Hot-Dry-Windy Index (HDW), a new fire-weather prediction tool based on the key atmospheric variables that affect wildland fire: temperature, moisture, and wind.
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"Predicting fire conditions is important and extremely difficult," said Joseph Charney, a research meteorologist with the Forest Service's Northern Research Station in Lansing, Mich., and a member of the research team behind HDW. "By focusing on just temperature, moisture and wind, we created a tool that works with the same weather models that are used every day in fire weather forecasts, and thus can be applied anywhere in the world, regardless of fuel conditions or topography."Alan Srock of St. Cloud State University is the lead author of a study describing HDW and its performance; co-authors include Charney, Brian Potter of the Forest Service's Pacific Northwest Research Station, and Scott Goodrick of the Southern Research Station. The study was published in the journal To test how accurately HDW predicts dangerous fire days, the scientists compared its predictions with fire behavior recorded during four recent wildfires in Minnesota, Texas, New Jersey and California. Researchers found that HDW performed better than an existing fire weather index called the Haines Index in identifying the day during each fire that was the most difficult to manage.One caveat the researchers make is that HDW is designed to anticipate when large-scale weather can affect a wildland fire; it is not designed to account for fine-scale weather, topography, and fuel conditions that affect fire behavior and can contribute to major management difficulties.As an aid to giving fire officials context for HDW values, the research team collaborated with Jessica McDonald of Texas Tech University to develop a 30-year HDW climatology that establishes locally and seasonally high HDW values for specific locations. These climatological values provide insight that can help fire managers who may not be from the local area evaluate whether temperature, humidity or wind speed are normal or not.While its performance so far is promising, more research is needed before HDW is ready to be used on an operational basis. "The HDW Index was designed to address the needs of the wildland firefighting community, and our early results show that HDW has the potential to help users make better decisions," Srock said.
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September 11, 2018
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https://www.sciencedaily.com/releases/2018/09/180911151858.htm
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'Cloud computing' takes on new meaning for scientists
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Clouds may be wispy puffs of water vapor drifting through the sky, but they're heavy lifting computationally for scientists wanting to factor them into climate simulations. Researchers from the University of California, Irvine, the Ludwig Maximilian University of Munich and Columbia University have turned to data science to achieve better cumulus calculating results.
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Their work is detailed in a study published online recently by "Clouds play a major role in the Earth's climate by transporting heat and moisture, reflecting and absorbing the sun's rays, trapping infrared heat rays and producing precipitation," said co-author Michael Pritchard, UCI assistant professor of Earth system science. "But they can be as small as a few hundred meters, much tinier than a standard climate model grid resolution of 50 to 100 kilometers, so simulating them appropriately takes an enormous amount of computer power and time."Standard climate prediction models approximate cloud physics using simple numerical algorithms that rely on imperfect assumptions about the processes involved. Pritchard said that while they can help produce simulations extending out as much as a century, there are some imperfections limiting their usefulness, such as indicating drizzle instead of more realistic rainfall and entirely missing other common weather patterns.According to Pritchard, the climate community agrees on the benefits of high-fidelity simulations supporting a rich diversity of cloud systems in nature."But a lack of supercomputer power, or the wrong type, means that this is still a long way off," he said. "Meanwhile, the field has to cope with huge margins of error on issues related to changes in future rainfall and how cloud changes will amplify or counteract global warming from greenhouse gas emissions."The team wanted to explore whether deep machine learning could provide an efficient, objective and data-driven alternative that could be rapidly implemented into mainstream climate predictions. The method is based on computer algorithms that mimic the thinking and learning abilities of the human mind.They started by training a deep neural network to predict the results of thousands of tiny, two-dimensional, cloud-resolving models as they interacted with planetary-scale weather patterns in a fictitious ocean world.The newly taught program, dubbed "The Cloud Brain," functioned freely in the climate model, according to the researchers, leading to stable and accurate multiyear simulations that included realistic precipitation extremes and tropical waves."The neural network learned to approximately represent the fundamental physical constraints on the way clouds move heat and vapor around without being explicitly told to do so, and the work was done with a fraction of the processing power and time needed by the original cloud-modeling approach," said lead author Stephan Rasp, an LMU doctoral student in meteorology who began collaborating with Pritchard on this project as a visiting scholar at UCI."I'm super excited that it only took three simulated months of model output to train this neural network," Pritchard said. "You can do a lot more justice to cloud physics if you only need to simulate a hundred days of global atmosphere. Now that we know it's possible, it'll be interesting to see how this approach fares when deployed on some really rich training data."The researchers intend to conduct follow-on studies to extend their methodology to trickier model setups, including realistic geography, and to understand the limitations of machine learning for interpolation versus extrapolation beyond its training data set -- a key question for some climate change applications that is addressed in the paper."Our study shows a clear potential for data-driven climate and weather models," Pritchard said. "We've seen computer vision and natural language processing beginning to transform other fields of science, such as physics, biology and chemistry. It makes sense to apply some of these new principles to climate science, which, after all, is heavily centered on large data sets, especially these days as new types of global models are beginning to resolve actual clouds and turbulence."Pierre Gentine, associate professor of Earth & environmental engineering at Columbia University, also participated in this study, which was funded by the U.S. Department of Energy, NASA, the National Science Foundation and the German Research Foundation.
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September 6, 2018
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https://www.sciencedaily.com/releases/2018/09/180906100442.htm
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Invasive pines fueled 2017 fires in Knysna, South Africa
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The replacement of natural fynbos vegetation with pine plantations in the southern Cape, and the subsequent invasion of surrounding land by invasive pine trees, significantly increased the severity of the 2017 Knysna wildfires.
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This is one of the findings of a study published in the journal Over four days in June 2017, the Knysna fires burnt 15000 hectares, claiming the lives of seven people and destroying more than 5000 hectares of commercial pine plantations and over 800 buildings.The researchers used satellite imagery to compare the landscape before and after the fire, including the type of vegetation covering the different areas. This information enabled them to estimate the amount of biomass consumed by the 2017 fire.One of the main findings is that the severity of the fire was significantly higher in plantations of invasive alien trees and in fynbos invaded by alien trees, than in uninvaded fynbos. And while the weather conditions were extreme, they were not unprecedented, as similar conditions occurred in the past at a rate of approximately one day every three years. The severity of the 18-24 month drought that preceded the fires, on the other hand, was higher than ever recorded in the historical weather record, and this contributed significantly to the impact of the fire.Prof. Brian van Wilgen, a fire ecologist with the CIB and one of the co-authors, says large tracts of natural vegetation in the southern Cape have been systematically replaced with plantations of Pinus and Eucalyptus species, increasing above-ground biomass from about four to 20 tonnes per hectare: "Given that more than two-thirds of the area that burned was in one of these altered conditions, our findings demonstrate clearly that fuel loads have substantially increased compared to earlier situations when the landscape would have been dominated by regularly burned uninvaded natural vegetation."It is estimated that pine trees have invaded more than 90% of the Garden Route National Park's fynbos vegetation at various densities. Additional invasions by Australian Acacia and Eucalyptus species cover a further 29% and 14% respectively: "By increasing the amount of fuel available to burn, the fires become more intense and more difficult to control," he explains. Van Wilgen warns, however, that events of this nature can become more frequent as the climate of the southern Cape becomes more hot and dry, and as the extent of invasions increases. "The conditions that exacerbated the severity of the 2017 Knysna fires will occur again. People need to stay vigilant and implement fire-wise practices, and, more importantly, steer away from placing developments in high-risk areas in the long inter-fire periods."Our study underscores the need to implement effective programs to control the spread of invasive alien plants, and to re-examine the economic and ecological sustainability of commercial planting of invasive alien trees in fire-prone areas."Some of the other finding include:
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September 5, 2018
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https://www.sciencedaily.com/releases/2018/09/180905140248.htm
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Physics model acts as an 'EKG' for solar panel health
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Companies and governments have regularly invested in solar farms and lost money when weather degradation unexpectedly cut panel lifetime short.
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As electricity generated from solar energy increasingly matches fossil fuels in price, companies are pressured to keep panels living past their warranty and stretch the billions of dollars paid up front for their construction.Diagnosing degraded solar panels sooner through a tool functioning like an electrocardiogram would contribute to lower electric bills on clean energy as well as cut manufacturing costs."We need to look at the heartbeat of a solar farm to understand its diseases," said Xingshu Sun, a recent doctoral graduate of Purdue University's School of Electrical and Computer Engineering.A solar farm's "heartbeat" is data on how well it generates electricity. Purdue researchers created an algorithm using the physics of panel degradation that can analyze solar farm data from anywhere, essentially as a portable EKG for solar farms."It's the difference between daily life and the doctor's office. Previously, facilities were just checking a solar farm's heartbeat in a controlled environment, like with an EKG in a hospital lab," said Muhammad Ashraful Alam, Purdue's Jai N. Gupta Professor of Electrical and Computer Engineering. "But a solar farm itself is always generating new field data for us to collect and analyze, so we need to bring the EKG to the field. This information-driven approach is transformative, because the approach would allow continuous monitoring and decision making. Ours is a first step in that direction."Real-time diagnostics would ultimately inform better panel designs -- the cost-saving "treatment" that could prolong lifespan and continue to cut electrical bills."If you look at solar modules on the market, their designs hardly differ no matter where they are in the world, just like how iPhones sold in the U.S. and China are almost identical," Sun said. "But solar modules should be designed differently, since they degrade differently in different environments."Degradation in humid environments, for example, comes in the form of corrosion, but high altitudes with no humidity cause degradation through the increased concentration of UV light. Like with human diseases, symptoms of corrosion or sun-beaten silicon tend to not show up on a solar panel until many years after the degradation started.Without knowing when degradation is happening, companies tend to compensate for different weather conditions by under- or over-designing solar panels, driving up manufacturing costs.Purdue researchers used public solar panel data provided by the National Renewable Energy Laboratory to pull together parameters of how well the panels are generating electricity, such as resistance and voltage. When fed into the algorithm, a curve generates to show the power output of a solar cell. Published findings appear in the journal The next step is improving the algorithm over time. Alam's lab has been collaborating with other Purdue research teams to develop DEEDS into a platform for preserving and sharing data, computational tools and scientific workflows from solar panel facilities as well as from a range of sources for other fields, including chemistry, nutrition science and environmental science.In the long term, the researchers hope the algorithm could show how much energy a solar farm produces in 30 years by looking at the relationship between weather forecast data and projection of electric circuit parameters. Integrating the algorithm with other physics-based models could eventually predict the lifetime of a solar farm.The algorithm is in an experimental stage, but already downloadable for other researchers to use through a National Science Foundation-funded platform called Digital Environment for Enabling Data-driven Science (DEEDS) at
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September 5, 2018
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https://www.sciencedaily.com/releases/2018/09/180905113638.htm
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When it rains, snake bites soar
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Hikers and trail runners be warned: Rattlesnakes and other venomous reptiles may bite more people during rainy years than in seasons wracked by drought, a new study shows.
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The research, which was led by Caleb Phillips of the University of Colorado Boulder and Grant Lipman of the Stanford University School of Medicine, examined 20 years of snakebite data from across California. Their findings contradict a popular theory among many wilderness health professionals that drought might increase snake bites by pushing the reptiles into the open where they are more likely to run into people.Instead, the group discovered that for every 10 percent increase in rainfall over the previous 18 months, cases of snake bites spiked by 3.9 percent in California's 58 counties.The results could have implications for efforts to prevent and treat dangerous encounters between humans and snakes, especially as climate patterns shift across the western United States."This study shows a possible unexpected, secondary result of climate change," said Phillips, an adjunct assistant professor in CU Boulder's Department of Computer Science. "We probably need to take climatological changes into account when we coordinate systems that may seem unrelated like planning how we distribute antivenin supplies or funding poison control centers."Phillips and his colleagues suspect that the reason for the surge in snake bites during wet years may come down to snake food. Mice and other rodents, the prime meals for rattlesnakes, flourish in rainy years -- and that might give snakes a boost.Phillips said that he'd be eager to find out if the same trends appear outside of California. Colorado is home to three closely-related species of venomous reptiles: prairie, western and massasauga rattlesnakes. Bites from these animals rarely kill humans, but tragedy can strike. Colorado triathlete Dan Hohs, for example, died from a rattlesnake bite in 2017.The researchers wondered how climate change might influence the frequency of such encounters. They pored through 5,365 cases of rattlesnake bites reported to the California Poison Control System between 1997 and 2017. The team compared those cases to a range of other information, including climate data from NASA and drought records from the National Drought Mitigation Center.What the group found was surprising: When California counties experienced drought, recorded cases of snake bites dropped off. Those incidents hit record low levels statewide in 2015 and 2016 when California was in the middle of a historic dry spell.The researchers published their findings today in the journal Research in Colorado and other parts of the United States suggests that the impact of warming temperatures on rainfall patterns will be a mixed bag -- with some regions experiencing more severe storms and others seeing drier weather.Phillips, an avid trail runner and trained wilderness first responder, urges outdoor enthusiasts like him to stay calm. "If you encounter a rattlesnake," Phillips said, "don't pick a fight with it, and it won't pick a fight with you."Other co-authors of the study include Derrick Lung and Hallam Gugelman of the University of California, San Francisco School of Medicine and Katie Doering of the Stanford School of Medicine.
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September 4, 2018
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https://www.sciencedaily.com/releases/2018/09/180904150403.htm
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California: Global warming, El Niño could cause wetter winters, drier conditions in other months
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So here's the good news: Despite fears to the contrary, California isn't facing a year-round drought in our warming new world.
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However, UC Riverside Earth Sciences Professor Robert Allen's research indicates that what precipitation the state does get will be pretty much limited to the winter months -- think deluge-type rainfall rather than snow -- and non-winter months will be even dryer than usual, with little or no rain at all."It is good news," Allen said. "But only relative to the alternative of no rain at all."Allen's latest findings build on his 2017 research that concluded global warming will bring increased winter precipitation to California through the end of this century.The findings are outlined in a paper by Allen and his co-author Ray Anderson, research soil scientist at the USDA-ARS US Salinity Lab, titled "21st century California drought risk linked to model fidelity of the El Niño teleconnection." It was published September 3 in The paper focuses on how "greenhouse-gas-induced climate change" will affect drought conditions in the state. The findings are based on 40 climate models that were compared to actual precipitation, soil moisture, and streamflow in the state between 1950 and 2000.Historically, about 90 percent of California's rain and snow have come during the winter months of December, January, and February, Allen said, with sporadic rain scattered over the rest of the year. But now, warming surface temperatures in the tropical Pacific Ocean are expected to amplify the rainy season by sending stormy El Niño conditions over the state in the winter.Bottom line, Allen said, the flooding and mudslides that accompanied the heavy winter rains of 2017 shouldn't be considered an aberration, but potentially California's new weather norm.The trick will be finding a way to capture excess water for dry periods, he said. "It's all about smoothing the seasonable differences. If we can take advantage of the enhanced winter rainfall, we can hopefully get through the drying trends the rest of the year."Trapping that winter precipitation will be a challenge, however, especially since it's likely to come more in the form of rain than snow due to the warming climate. Historically, snow in the mountains feeds reservoirs and provides water to agriculture when it is needed in the summer, but rain will just run off unless it is captured.Allen's findings also bode ill for California's fire season. The state's new norm could mimic -- or surpass -- the fire season of 2017, the worst in California's history, as wet winters encourage lush spring growth that will quickly parch during the hot and dry season, becoming wildfire fuel.In fact, Allen said, these "new norm" projections aren't for a distant future."I think it's here now, so we need to start acting as quickly as possible," he said. "Adaptation is incredibly important in response to climate change, and in this case it means enhancing our water storage capabilities, our reservoirs and dam structures, because things are going to become drier in the nonwinter months."And for ordinary citizens? This might be a great time to start investing in rain barrels."In Southern California, it could mean having native plants in your yard because a grass yard has to be irrigated, and that's probably not the wisest use of water," he said. "It's all about living sustainably."
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September 4, 2018
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https://www.sciencedaily.com/releases/2018/09/180904103249.htm
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Satellites more at risk from fast solar wind than a major space storm
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Satellites are more likely to be at risk from high-speed solar wind than a major geomagnetic storm according to a new UK-US study published this week in the Journal
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Researchers investigating the space weather risks to orbiting satellites calculated electron radiation levels within the Van Allen radiation belts. This ring-doughnut-shaped zone wraps around the Earth, trapping charged particles. Geostationary orbit lies inside the Van Allen radiation beltsThe study, which analysed years of satellite data, found that electron radiation levels at geostationary orbit could remain exceptionally high for 5 days or more, even after the solar wind speed had died down. As a result, electronic components on satellites could charge up to dangerously high levels and become damaged.Professor Richard Horne, lead author of the study, said:"Until now we thought that the biggest risk to orbiting satellites was geomagnetic storms. Our study constructed a realistic worst-case event by looking at space weather events caused by high-speed solar wind flowing away from the Sun and striking the Earth. We were surprised to discover just how high electron radiation levels can go."This new research is particularly interesting to the satellite industry. Professor Horne continues:"Fast solar wind is more dangerous to satellites because the geomagnetic field extends beyond geostationary orbit and electron radiation levels are increased all the way round the orbit -- in a major geomagnetic storm the field is distorted and radiation levels peak closer to the Earth."Electronic components on satellites are usually protected from electrostatic charges by encasing them in metal shielding. You would have to use about 2.5 mm of aluminium to reduce charging to safe levels -- much more than is used at present. There are well over 450 satellites in geostationary orbit and so in a realistic worst case we would expect many satellites to report malfunctions and a strong likelihood of service outage and total satellite loss."Dr Nigel Meredith, a co-author on the study, said:"A few years ago, we calculated electron radiation levels for a 1 in 150 year space weather event using statistical methods. This study uses a totally different approach but gets a very similar result and confirms that the risk of damage is real."The solar wind is a stream of particles and magnetic field flowing away from the Sun. It flows around the Earth's magnetic field and excites so-called 'chorus' plasma waves near geostationary orbit. Chorus waves accelerate electrons and form the Van Allen radiation belts. The chorus waves also travel along the geomagnetic field to the Polar Regions where they are detected on the ground at Halley Research Station, Antarctica.
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August 29, 2018
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https://www.sciencedaily.com/releases/2018/08/180829081339.htm
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Mangrove expansion and climatic warming may help ecosystems keep pace with sea level rise
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Sea level rise and extreme weather events have become harsh realities for those living along the world's coasts. The record-breaking hurricanes of the past decade in the United States have led to staggering tolls on coastal infrastructure and communities, leading many local governments to consider the benefits of natural coastal barriers.
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In a landmark study titled "Warming accelerates mangrove expansion and surface elevation gain in a subtropical wetland," a team of Villanova University biologists has documented that coastal wetlands in the southeastern United States are responding positively to rising temperatures both in their growth and in their ability to build soil to keep pace with sea level rise.Published August 29 in the British Ecological Society's The Villanova research team's two-year experiment, funded by grants from the National Aeronautics and Space Administration (NASA), was performed at the Kennedy Space Center (KSC) within the Merritt Island National Wildlife Refuge (MINWR) on Merritt Island. The KSC was an ideal location to conduct the research being situated at the intersection of two wetland biomes, salt marshes and mangroves. The implications for the KSC are serious since coastal wetlands and sand dunes help protect NASA's $5.6 billion low-lying infrastructure against rising seas.The large-scale warming experiment was conducted in place in the MINWR using large passive warming chambers to increase both marsh and mangrove ecosystem air temperatures. The Villanova researchers found that experimental warming both doubled plant height and accelerated the transition from marsh to mangrove.Mangroves are woody trees with more complex roots than their grassy marsh plant counterparts. When subjected to temperatures similar to those that will occur in a warmer future, mangrove plots showed increased surface elevation which is a measure of the wetland's ability to build soil and keep pace with sea level rise."Our study provides some evidence that the ongoing reshuffling of species on earth's surface could allow for some adaptation to the same global changes that are causing them," says Chapman. "Conserving and restoring our coastal wetlands can help humans adapt to climate change."With their unique structure and migration to higher latitudes caused by climate change, mangroves may help coasts keep pace with sea level rise and combat severe weather events like hurricanes. Expansion of these natural barriers in areas like the Kennedy Space Center may enhance the sustainability of coastal communities as they face accelerating sea-level rise in a warmer future."The study links the growth of individual plants, and particularly their roots, to the survival of an entire ecosystem. The long-term strength of the mangrove effects we identified may determine what the maps of our southeastern coastlines look like in the future," says Langley. "This mangrove effect could benefit coastal wetlands around the world.""Our experiment highlights the impact multiple interacting aspects of climate change, such as warming and sea level rise, can have on the outcome of species invasions resulting from climate change -- and on the capacity of those communities to protect shorelines," concluded Coldren.
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August 28, 2018
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https://www.sciencedaily.com/releases/2018/08/180828133931.htm
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Wilder wildfires ahead?
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At roughly 415,000 acres, Northern California's Mendocino Complex Fire is now the state's largest recorded wildfire, surpassing the record held by Santa Barbara and Ventura counties' Thomas Fire, which occurred less than a year before. Roughly 10 other large-scale conflagrations are threatening the state. And California is not yet even at the height of its wildfire season.
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The trend of growing intensity and extremity of recent wildfires has triggered new research by scientists at UC Santa Barbara's Bren School of Environmental Science & Management and at the National Center for Atmospheric Research. Their question: How is one of our most significant climate patterns -- the El Niño/Southern Oscillation (ENSO) -- being affected by a warming Earth and how, in turn, is that pattern affecting the likelihood and intensity of future wildfires? Their findings could have implications on land use and on wildfire fighting and prevention strategies at urban/wildland interfaces.Their study, "ENSO's Changing Influence on Temperature, Precipitation and Wildfire in a Warming Climate," has been published in the American Geophysical Union journal "This paper is really saying that in fire-prone places like California and Australia, we can expect future El Niño and La Niña events to have a bigger impact on fire risk in a given year," said Samantha Stevenson, a faculty member with the Bren School and a co-author on the paper. "That's because the sensitivity of land temperature and precipitation to changes in tropical Pacific Ocean temperature is increasing due to climate change."Like many climate-based events, which take place over long timescales, tracking the ripple effects of a climate pattern can be difficult, given the many individual processes that can affect the result. ENSO -- the collective name for the ocean-warming El Niño weather pattern and its complementary ocean-cooling La Niña pattern -- has particularly complex and extreme teleconnections. It drives drought in some places while promoting fertile vegetation in others. Food sources may dwindle in some regions, while fresh water supplies may be built in others. In the process, human populations and their supports -- such as agricultural production, energy use and fire prevention -- are affected.The researchers used large "ensemble" sets of climate simulations, projecting future climate under a business-as-usual climate scenario assuming no major efforts to combat climate change. They then examined changes in the sensitivities of regional climate to ENSO-related sea surface temperature anomalies between the historical period and the late 21st century. In addition to looking at changes in ENSO-driven temperature and rainfall patterns, one of the climate models (the Community Earth System Model, or CESM) includes a wildfire scheme that simulates the risk of fire activity based on factors such as soil moisture, fuel load and applied statistical relationships between fire season length and burned area to simulate fire activity. All of the quantities the researchers examined showed an increase in the future effects of El Niño and La Niña events -- in other words, we can expect a larger ENSO-driven "bang for your buck" in the future."Typically what happens during an El Niño or La Niña event is you get changing atmospheric circulation patterns," Stevenson explained. These changes in atmospheric circulation patterns, which originate in the ocean as rising or falling sea surface temperatures, in turn can cause shifts in things like wind patterns, cloud cover, atmospheric temperature and precipitation, which then affect conditions on land. According to the researchers, these impacts will be intensifying in the future as the Earth warms."Future ENSO is having a larger impact on the land surface since the Earth is warming -- and it's easier for land to warm than the ocean in general, because it has a lower heat capacity -- so the land is going to be evaporating more moisture," Stevenson said. Add an El Niño event on top of that, she added, and the level of evaporation will increase. With drier soils and fuels, the likelihood and intensity of wildfires are also bound to increase.Climate scientists still aren't sure how strong El Niño and La Niña events themselves will actually be in the future, Stevenson stressed, but what they do agree on is that events of a given magnitude will cause larger impacts to wildfire risks as the Earth warms, worsening fires in areas that already experience them, and creating conditions for them where they aren't currently a big risk. Finding these pieces of the puzzle will be critical for future studies and wildfire fighting strategies, she said."To me this just really highlights the importance of getting future projections of El Niño impacts and magnitudes correct," Stevenson said.The study is funded by National Science Foundation and the U.S. Department of Energy. The study was led by NCAR scientist John Fasullo and co-authored by Bette Otto-Bliesner, also of NCAR.
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August 27, 2018
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https://www.sciencedaily.com/releases/2018/08/180827151542.htm
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Connectivity explains ecosystem responses to rainfall, drought
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In a new study published in the
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"Information arising from fluctuations in rainfall moves through ecosystems, similar to the way that information flows through communication networks," said Praveen Kumar, a professor of civil and environmental engineering at the University of Illinois at Urbana-Champaign and study co-author. "This type of analysis, which is new to ecological and hydrological studies, lets us determine how well different aspects of an ecosystem are connected and whether responses to changes in climate are site-specific or common across different ecosystems."The researchers looked at changes in heat, soil moisture and carbon flow -- known as fluxes -- before, during and after rainfall and drought events in two locations. The first site, in southwestern Idaho, experienced several days of rainfall during July 2015. The second, in the Southern Sierra region of California, experienced a multiyear drought starting in 2012."At the Idaho site, we saw increased connectivity between the atmosphere and soil in the period directly after the rainfall," said Allison Goodwell, a civil engineering professor at the University of Colorado, Denver who is a former Illinois graduate student and lead author of the new study. "At the Southern Sierra site, we found that heat and carbon fluxes responded to the drought in different ways, and that sources of connectivity varied between high- and low-elevation sites.""Another aspect that made this study unique was the availability of data from multiple stations at different elevations at each site," Kumar said. "This allowed us to see if the changes in connectivity were due to climate differences resulting from elevation. Normally, the data collection stations are isolated, making it difficult to perform this type of comparative analysis."Although the field sites and data are from different ecosystems, times and weather disturbances, the study provides insight into how connectivity influences different types of fluxes, the researchers said. Stronger connectivity alters how rainfall affects moisture, heat and carbon flux in the system, and the progression from early to late-stage drought."These results show the ways in which a watershed may respond to precipitation disturbances, in this case drought," said Richard Yuretich, the program director for the NSF Critical Zone Observatories. "The information is important to predicting how ecosystems will respond to future extreme events."Aaron Fellows and Gerald Flerchinger from the U.S. Department of Agriculture also contributed to this research.The National Science Foundation Grant for the Critical Zone Observatory for Intensively Managed Landscapes and the NASA Earth and Space Science Fellowship supported this research.
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August 23, 2018
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https://www.sciencedaily.com/releases/2018/08/180823103827.htm
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Smartphones may be used to better predict the weather
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Flash floods occur with little warning. Earlier this year, a flash flood that struck Ellicott City, MD, demolished the main street, swept away parked cars, pummeled buildings and left one man dead.
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A recent Tel Aviv University study suggests that weather patterns that lead to flash floods may one day be tracked and anticipated by our smartphones."The sensors in our smartphones are constantly monitoring our environment, including gravity, the earth's magnetic field, atmospheric pressure, light levels, humidity, temperatures, sound levels and more," said Prof. Colin Price of TAU's Porter School of the Environment and Earth Sciences, who led the research. "Vital atmospheric data exists today on some 3 to 4 billion smartphones worldwide. This data can improve our ability to accurately forecast the weather and other natural disasters that are taking so many lives every year."Prof. Price collaborated with TAU master's student Ron Maor and TAU doctoral student Hofit Shachaf for the study, which was published in the Smartphones measure raw data, such as atmospheric pressure, temperatures and humidity, to assess atmospheric conditions. To understand how the smartphone sensors work, the researchers placed four smartphones around TAU's expansive campus under controlled conditions and analyzed the data to detect phenomena such as "atmospheric tides," which are similar to ocean tides. They also analyzed data from a UK-based app called WeatherSignal."By 2020, there will be more than six billion smartphones in the world," Prof. Price said. "Compare this with the paltry 10,000 official weather stations that exist today. The amount of information we could be using to predict weather patterns, especially those that offer little to no warning, is staggering."In Africa, for example, there are millions of phones but only very basic meteorological infrastructures. Analyzing data from or 10 phones may be of little use, but analyzing data on millions of phones would be a game changer. Smartphones are getting cheaper, with better quality and more availability to people around the world."The same smartphones may be used to provide real-time weather alerts through a feedback loop, Prof. Price said. The public can provide atmospheric data to the "cloud" via a smartphone application. This data would then be processed into real-time forecasts and returned to the users with a forecast or a warning to those in danger zones.The study may lead to better monitoring and predictions of hard-to-predict flash floods. "We're observing a global increase in intense rainfall events and downpours, and some of these cause flash floods," Prof. Price said. "The frequency of these intense floods is increasing. We can't prevent these storms from happening, but soon we may be able to use the public's smartphone data to generate better forecasts and give these forecasts back to the public in real time via their phones."
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Weather
| 2,018 |
August 22, 2018
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https://www.sciencedaily.com/releases/2018/08/180822101037.htm
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Napoleon's defeat at Waterloo caused in part by Indonesian volcanic eruption
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Electrically charged volcanic ash short-circuited Earth's atmosphere in 1815, causing global poor weather and Napoleon's defeat, says new research.
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Historians know that rainy and muddy conditions helped the Allied army defeat the French Emperor Napoleon Bonaparte at the Battle of Waterloo. The June 1815 event changed the course of European history.Two months prior, a volcano named Mount Tambora erupted on the Indonesian island of Sumbawa, killing 100,000 people and plunging the Earth into a 'year without a summer' in 1816.Now, Dr Matthew Genge from Imperial College London has discovered that electrified volcanic ash from eruptions can 'short-circuit' the electrical current of the ionosphere -- the upper level of the atmosphere that is responsible for cloud formation.The findings, published today in Dr Genge, from Imperial's Department of Earth Science and Engineering, suggests that the Tambora eruption short-circuited the ionosphere, ultimately leading to a pulse of cloud formation. This brought heavy rain across Europe that contributed to Napoleon Bonaparte's defeat.The paper shows that eruptions can hurl ash much higher than previously thought into the atmosphere -- up to 100 kilometres above ground.Dr Genge said: "Previously, geologists thought that volcanic ash gets trapped in the lower atmosphere, because volcanic plumes rise buoyantly. My research, however, shows that ash can be shot into the upper atmosphere by electrical forces."A series of experiments showed that that electrostatic forces could lift ash far higher than by buoyancy alone. Dr Genge created a model to calculate how far charged volcanic ash could levitate, and found that particles smaller than 0.2 millionths of a metre in diameter could reach the ionosphere during large eruptions.He said: "Volcanic plumes and ash both can have negative electrical charges and thus the plume repels the ash, propelling it high in the atmosphere. The effect works very much like the way two magnets are pushed away from each other if their poles match."The experimental results are consistent with historical records from other eruptions.Weather records are sparse for 1815, so to test his theory, Dr Genge examined weather records following the 1883 eruption of another Indonesian volcano, Krakatau.The data showed lower average temperatures and reduced rainfall almost immediately after the eruption began, and global rainfall was lower during the eruption than either period before or after.He also found reports of ionosphere disturbance after the 1991 eruption of Mount Pinatubo, Philippines, which could have been caused by charged ash in the ionosphere from the volcano plume.In addition, a special cloud type appeared more frequently than usual following the Krakatau eruption. Noctilucent clouds are rare and luminous, and form in the ionosphere. Dr Genge suggests these clouds therefore provide evidence for the electrostatic levitation of ash from large volcanic eruptions.Dr Genge said: "Victor Hugo in the novel Les Miserables said of the Battle of Waterloo: 'an unseasonably clouded sky sufficed to bring about the collapse of a World.' Now we are a step closer to understanding Tambora's part in the Battle from half a world away."
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Weather
| 2,018 |
August 20, 2018
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https://www.sciencedaily.com/releases/2018/08/180820113029.htm
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Nearly two million acres on fire in the United States
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The West Coast of the United States is shrouded in smoke from the 110 large fires (this does not include smaller fires within each complex of fires) that have erupted across the region during this fire season.
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Over 1.9 million acres are or have been ablaze. Six new large fires were reported in Idaho, Nevada and Oregon over the weekend and eight large fires have been contained including the Ferguson Fire near Yosemite National Park in California.The weather concerns in the area include warmer than average temperatures that will continue in the west with diurnal winds and marginal overnight humidity recoveries. Isolated storms will be possible along and west of the Continental Divide in Montana and Wyoming. These storms could also bring more lightning strikes and more blazes to the area with increasingly dry conditions. A breezy easterly flow will blow across the western half of Montana and possibly northern Idaho that could possibly allow fires to spread farther. With the center of the high pressure area located mostly over southern California, the normal wind flow will be suppressed and the rain that might come to this area will be contained mainly in areas near the Mexican Border certainly not helping firefighting efforts. Further north, low pressure will bring cooler temperatures and possibly isolated storms to the Pacific Northwest.National Preparedness Level is at the highest level of 5. This level includes national mobilization heavily committed to fighting active fires and taking measure to support these geographic areas that are on fire. Taking emergency measures to sustain incident operations on active fires. Providing ongoing full commitment of national resources. Filling resource orders at the National Interagency Coordination Center by coordinating requests with Geographic Area Coordination Centers as resources become available. Recognizing that the potential for emerging significant wildland fires is high and expected to remain high in multiple geographic areas.Smoke from these fires have traveled along the west to east jet stream and are bringing that smoke across the country as far as the East Coast. NOAA's High-Resolution Rapid Refresh-Smoke (HRRR-Smoke) air quality modeling system is a web-based system that runs in real time and also is predictive of where the smoke may travel taking into account the movements the atmosphere normally takes following the laws of science and those can be calculated mathematically which produces a forecast. The HRRR-Smoke processes data from numerous sources, such as weather balloons, surface observations, aircraft, satellites and other atmospheric monitoring resources to approximate the physics, chemistry and dynamics of the atmosphere but at high resolutions on some of the most powerful computers in existenceThis image shows the current movement of the smoke across the U.S.:This map (10am EDT on August 20, 2018) comes from NOAA and is an experimental model showing both upper level on near-surface smoke. This particular iteration of the map is showing the near-surface smoke (expressed in ?g/m3) from the HRRR-Smoke Model. The Near-Surface Smoke overlays 10-meter wind data, expressed in knots. The colors represent the fire emitted fine particulate matter (fire smoke) concentrations at ~8 meters above the ground. The darker and redder the color the more concentration of smoke particulates are present. It is interesting to see how the smoke moves across the country traveling south as far as Texas and east as far as Quebec. When wind patterns change, of course, so does the smoke pattern. WTOP, a local radio station near Washington DC, reported that smoke from the California fires had reached the DC Metro area this past week.Smoke from any type of wildfire is dangerous. The smoke released by any type of fire is a mixture of particles and chemicals produced by incomplete burning of carbon-containing materials. All smoke contains carbon monoxide, carbon dioxide and particulate matter (PM or soot). Smoke can contain many different chemicals, including aldehydes, acid gases, sulfur dioxide, nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, styrene, metals and dioxins. The type and amount of particles and chemicals in smoke varies depending on what is burning, how much oxygen is available, and the burn temperature. Exposure to high levels of smoke should be avoided. Individuals are advised to limit their physical exertion if exposure to high levels of smoke cannot be avoided. Individuals with cardiovascular or respiratory conditions (e.g., asthma), fetuses, infants, young children, and the elderly may be more vulnerable to the health effects of smoke exposure.
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Weather
| 2,018 |
August 20, 2018
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https://www.sciencedaily.com/releases/2018/08/180820085248.htm
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Nice sunny days can grow into heat waves -- and wildfires: summer weather is stalling
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Be it heavy downpours or super-hot spells, summer weather becomes more persistent in North America, Europe and parts of Asia. When those conditions stall for several days or weeks, they can turn into extremes: heatwaves resulting in droughts, health risks and wildfires; or relentless rainfall resulting in floods. A team of scientists now presents the first comprehensive review of research on summer weather stalling focusing on the influence of the disproportionally strong warming of the Arctic as caused by greenhouse-gas emissions from burning fossil fuels. Evidence is mounting, they show, that we likely meddle with circulation patterns high up in the sky. These are affecting, in turn, regional and local weather patterns -- with sometimes disastrous effects on the ground. This has been the case with the 2016 wildfire in Canada, another team of scientists show in a second study.
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"Giant airstreams encircle our globe in the upper troposphere -- we call them planetary waves," explains Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research (PIK) and co-author of the second paper. "Now evidence is mounting that humanity is messing with these enormous winds. Fueled by human-made greenhouse-gas emissions, global warming is probably distorting the natural patterns." Usually the waves, conveying chains of high- and low-pressure domains, travel eastwards between the equator and the North Pole. "Yet when they get trapped due to a subtle resonance mechanism," says Schellnhuber, "they slow down so the weather in a given region gets stuck. Rains can grow into floods, sunny days into heat waves, and tinder-dry conditions into wildfires.""While it might not sound so bad to have more prolonged sunny episodes in summer, this is in fact a major climate risk," says Dim Coumou from the Potsdam Institute for Climate Impact Research (PIK) and Vrije Universiteit Amsterdam, lead-author of the review paper and co-author of the wildfire case study. "We have rising temperatures due to human-caused global warming which intensifies heat waves and heavy rainfall, and on top of that we could get dynamical changes that make weather extremes even stronger -- this is quite worrying." This summer is an impressive example of how stalling weather can impact societies: persistent hot and dry conditions in Western Europe, Russia and parts of the US threaten cereal yields in these breadbaskets.Tons of studies have appeared on this topic in recent years, sometimes with seemingly conflicting results. For the paper now published in "Under global warming, the Indian summer monsoon rainfall will likely intensify and this will also influence the global airstreams and might ultimately contribute to more stalling weather patterns. All of these mechanisms do not work in isolation but interact," says Wang. "There is strong evidence that winds associated with summer weather systems are weakening and this can interact with so-called amplified quasi-stationary waves. These combined effects point towards more persistent weather patterns, and hence more extreme weather."The wildfire in Canada's Alberta region in 2016 is one stark example for the potentially disastrous impact of planetary-waves slow-down and the resulting summer-weather stalling. In a study now published in Scientific Reports, the other research team shows that indeed the blaze has been preceded by the trapping of a specific kind of airstreams in the region. In combination with a very strong El-Nino event this favored unusually dry and high-temperature conditions on the ground, entailing an increased fire hazard here. It took two months before the officials eventually could declare the fire to be under control. This was the costliest disaster in Canadian history with total damages reaching 4.7 billion Canadian Dollars."Clearly, the planetary wave pattern wasn't the only cause for the fire -- yet it was an additional important factor triggering a deplorable disaster," says Vladimir Petoukhov from PIK, lead-author of the case study. "In fact, our analysis reveals that beyond that single event, actually from the 1980s on, planetary waves were a significant factor for wildfire risks in the region. Since it is possible to detect the wave patterns with a relatively long lead-time of ten days, we hope that our findings can help forest managers and fire forecasters in the future.""Computer simulations generally support the observations and our theoretical understanding of the processes, so this seems pretty robust," concludes Coumou. "However, the observed changes are typically more pronounced than those seen in climate models." So either the simulations are too conservative, or the observed changes are strongly influenced by natural variability. "Our review aims at identifying knowledge gaps and ways forward for future research," says Coumou. "So there's still a lot to do, including machine learning and the use of big data. While we do not have certainty, all in all the state of research indicates that changes in airstreams can, together with other factors, lead to a phenomenon that sounds funny but isn't: extreme extremes."
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Weather
| 2,018 |
August 13, 2018
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https://www.sciencedaily.com/releases/2018/08/180813113329.htm
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Historic space weather could clarify what's next
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Historic space weather may help us understand what's coming next, according to new research by the University of Warwick.
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Professor Sandra Chapman, from Warwick's Centre for Fusion, Space and Astrophysics, led a project which charted the space weather in previous solar cycles across the last half century, and discovered an underlying repeatable pattern in how space weather activity changes with the solar cycle.The sun goes through solar cycles around every eleven years, during which time the number of sunspots increases to the maximum point (the 'solar maximum'). More solar activity means more solar flares, which in turn can mean more extreme space weather at earth.This breakthrough will allow better understanding and planning for space weather, and for any future threats it may pose to the Earth.Space weather can disrupt electronics, aviation and satellite systems and communications -- this depends on solar activity, but as this is different for each solar cycle, the overall likelihood of space weather events can be difficult to forecast.This exciting research shows that space weather and the activity of the sun are not entirely random -- and may constrain how likely large weather events are in future cycles.Sandra Chapman, Professor from the University of Warwick's Department of Physics and the lead author, commented:"We analysed the last five solar maxima and found that although the overall likelihood of more extreme events varied from one solar maximum to another, there is an underlying pattern to their likelihood, which does not change."If this pattern persists into the next solar maximum, our research, which constrains how likely large events are, will allow better preparation for potential space weather threats to Earth."The drivers of space weather, the sun and solar wind, and the response seen at Earth, have now been almost continually monitored by ground and space based observations over the last five solar cycles (more than fifty years).Each solar cycle has a different duration and peak activity level, and, as a consequence the climate of Earth's space weather has also been different at each solar maximum.The more extreme events are less frequent so that it is harder to build up a statistical picture of how likely they are to occur.
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Weather
| 2,018 |
August 7, 2018
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https://www.sciencedaily.com/releases/2018/08/180807171053.htm
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New technique for modeling turbulence in the atmosphere
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Army researchers have designed a computer model that more effectively calculates the behavior of atmospheric turbulence in complex environments, including cities, forests, deserts and mountainous regions.
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This new technology could allow Soldiers to predict weather patterns sooner using the computers at hand and more effectively assess flight conditions for aerial vehicles on the battlefield.Turbulence may be invisible to the naked eye, it is always present around us in the air in the form of chaotic changes in velocity and pressure.Traditional computational fluid dynamics methods of analyzing atmospheric turbulence treat the fluid as a continuum, solving the nonlinear Navier-Stokes differential equations that are involved.However, calculating the turbulence in the planetary boundary layer, the lowest layer of the atmosphere, can be difficult due to how the presence of trees, tall buildings and other aspects of the landscape directly influences its behavior.TCFD methods must account for all effects of the neighboring points surrounding the target, which creates an immense computational load that is very difficult to implement efficiently on modern parallel architectures, such as Graphics Processing Unit accelerators.As a result, these methods often face challenges when confronted with more intricate environments due to limitations in treating complex surface boundaries.In an attempt to search for an alternative approach, a team of U.S. Army Research Laboratory scientists led by Dr. Yansen Wang turned to the field of statistical mechanics for ideas.What they found was the Lattice-Boltzmann method, a technique used by physicists and engineers to predict fluid behavior on a very small scale."The Lattice-Boltzmann method is normally used to predict the evolution of a small volume of turbulence flows, but it has never been used for an area as large as the atmosphere," Wang said. "When I read about it in a research paper, I thought that it could be applied to not just a small volume of turbulence but also atmospheric turbulence."Unlike TCFD methods, the LBM treats the fluid like a collection of particles instead of a continuum and has been widely used in fluid simulation to accurately portray fluid dynamics.Wang and his team determined that this new approach could accurately model atmospheric turbulence while requiring much less computation than if they had solved for the NS differential equations.This fundamental change essentially allowed them to disregard a huge chunk of the neighboring points on the grid model, cutting the number of neighboring behaviors to account for and significantly lessening the computational load.As a result of their investigation, the researchers used the newly developed multi-relaxation-time Lattice-Boltzmann method to create an advanced Atmospheric Boundary Layer Environment model, which specifically treated highly turbulent flow in complex and urban domains.This marks the first time that an advanced MRT-LBM model has been used to model the atmosphere.The newly developed ABLE-LBM model paves the way for a highly-versatile approach to atmospheric boundary layer flow prediction.In addition to providing faster operating speed and simpler complex boundary implementation, this approach is intrinsically parallel and thus compatible with modern parallel architectures, making it a potentially viable modeling method on tactical compute platforms for the U.S. military."On the battlefield, you want atmospheric turbulence data quickly but you don't necessarily have any supercomputers on hand," Wang said. "However, you do have modern computer architecture with thousands of processors that make computing fast if the algorithm is appropriate. With the ABLE-LBM, you can use those modern computer architectures to compute turbulence on the battlefield without having to connect to a high performance computing center."The development of the ABLE-LBM model has significant ramifications on many other aspects of Army operations besides weather forecast.Atmospheric turbulence can significantly affect the behavior of optic and acoustic waves, which directly impact what Soldiers can see and hear.It can act as an important factor in reconnaissance and change the path that a laser travels or how sounds are emitted from a system.Small unmanned aerial systems are also at the mercy of turbulence vortices, which can occur when a gust of wind hits a building.Knowing how the turbulence will behave can help sUAS avoid collisions and even take advantage of existing updrafts to fly without their propellers to save energy.Potential applications can also be found outside the military in civilian life.Better knowledge of boundary layer turbulence can assist in civil planning in both preparation and emergency response when dealing with chemical spills, industrial fires and other man-made or natural disasters."Many people are interested in applying this method in various fields," Wang said. "This technique has paved a new way to model atmospheric turbulence. Our research was the first to set the path for this new direction, so we have a lot of proving to do."
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Weather
| 2,018 |
August 7, 2018
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https://www.sciencedaily.com/releases/2018/08/180807144944.htm
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Oregon has its share of fire storms
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Oregon, one state above California, is also having its share of fire storms and weather concerns. Five large fires/complexes are alight in the southwest corner of the state and all started on the same day with a region-wide lightning storm.
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The Garner Complex is an 8,886 acre wildfire north of the community of Rogue River in Jackson County, Oregon. The Complex is burning in a checkerboard mix of lands managed by the Bureau of Land Management and private landowners. The steep rocky terrain and historically high temperatures presented challenges for fire suppression efforts. The fire threatened valuable several hundred residences, private timber lands and habitat for threatened species. The fire began with a region-wide lightning storm on July 15 which ignited 12 fires that became the Garner Complex. The Taylor Creek Fire was added to the complex, but later grew to a point where it required its own management team. Currently, well over half of the fire has no active operations, only daily monitoring and patrol. Fire managers expect that they will place the remaining portions of the fire in patrol status at the end today's shift.The Taylor Creek fire once part of the Garner Complex grew to 41,103, much larger than the whole of the Garner Complex. This fire is now 38% contained but continues to exhibit moderate fire behavior with uphill runs, backing, and isolated torching. As with most of the fires in the West this year the prevailing problem has been the weather. Record temperatures, high winds, dry conditions and low humidity continue throughout the region making firefighting more difficult and fire growth much easier.The Klondike fire just southwest of the Taylor Creek fire is 30,873 acres and is 15% contained. This fire began on the same day as the other fires during the region-wide lightning storm on July 15. This fire, however, continues to be very active with large amounts of fuel available including litter and understory, grass, and chapparal. Fire behavior has included torching,spotting, and uphill runs. Weather concerns are the same as for the two preceding fires since they are all located near each other.The Sugar Pine fire located near Prospect, Oregon, was also the result of the July 15 lightning storm. It is currently at 8,885 acres. There are 704 personnel fighting this fire at present. The weather concerns for this fire include hot, dry conditions, with low humidity and winds. The fuels for the fire include grass, brush, and timber.The South Umpqua Complex consists of the Miles, Columbus, Cripple Creek, Snow shoe, and Railroad Gap fires primarily South/Southeast of Tiller, Oregon. The total size of the complex is 28,723 acres and is 18% contained at present. These fires also began on July 15. Fire behavior exhibited by this complex includes active, short-range spotting, group torching, single tree torching, running, flanking and backing surface fire. Weather concerns also are in place for this complex with hot, dry conditions, low humidity, excess fuels in place, and winds.
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Weather
| 2,018 |
August 6, 2018
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https://www.sciencedaily.com/releases/2018/08/180806162726.htm
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Rain-on-snow flood risk to increase in many mountain regions of the western U.S., Canada
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Flooding caused by rain falling on snowpack could more than double by the end of this century in some areas of the western U.S. and Canada due to climate change, according to new research from the University of Colorado Boulder and the National Center for Atmospheric Research (NCAR).
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The greatest flood risk increases are projected for the Sierra Nevada, the Colorado River headwaters and the Canadian Rocky Mountains -- places where residents are no strangers to flood concerns. Conversely, lower elevations in coastal regions of California, Oregon, Washington and maritime British Columbia could see decreases in rain-on-snow flood risk.The findings were published today in the journal Rain-on-snow events vary widely in timing and scale but can cause costly and damaging flooding as rapid snowmelt triggered by heavy and prolonged rainfall converge in a cascade that can overwhelm downstream rivers and reservoirs. In 2017, California's Oroville Dam nearly failed catastrophically due to such an event, leading to the evacuation of 188,000 people and $1 billion in infrastructure damages."Rain-on-snow events can be intense and dangerous in mountainous areas, but they are still relatively poorly understood," said Keith Musselman, lead author of the study and a research associate at CU Boulder's Institute of Arctic and Alpine Research (INSTAAR). "We can infer a little bit from streamflow, but we want to get better measurements and model more of the variables involved."To study the past, present and potential future of rain-on-snow events, the researchers turned to a state-of-the-art weather modeling dataset developed at NCAR. Known as CONUS 1, the dataset contains weather simulations across the continental U.S. in the current climate and a warmer future based on projected climate trends. The enormous data trove -- which took NCAR's Yellowstone supercomputer more than a year to compile -- offers unprecedented detail and resolution."This high-res dataset allows us to resolve mountains in granular fashion and examine the factors that combine to melt the snowpack when a warm storm comes in and hits cold mountains like the Sierra," Musselman said.The authors found that in a warmer climate, less frequent snow-cover at lower elevations would decrease the risk for rain-on-snow flood events in areas like the U.S. Pacific Northwest. By contrast, at higher elevations where winter snow will still accumulate despite climate warming (such as in the High Sierra and much of the Rocky Mountains), rain-on-snow events could become more frequent due to increased rainfall that might once have fallen as snow. The events will also become more intense.The rain and melt produced during rain-on-snow events is projected to increase for a majority of western North American river basins as rain rather than snow affects more mountain watersheds, increasing the corresponding flood risk by as much as 200 percent in localized areas and potentially straining existing flood control infrastructure."We were surprised at how big some of the projected changes were," Musselman said. "We didn't expect to see huge percentage increases in places that already have rain-on-snow flooding."The findings represent an important first step toward better understanding rain-on-snow flood risk in the context of anthropogenic climate change, which could significantly shift the timing and extent of future flood regimes.The researchers hope that continued investment in snowpack monitoring networks and efforts such as NASA's Airborne Snow Observatory will provide additional ground information, allowing hydrologists and climate scientists to verify their models against observations and better inform flood risk assessment now and in the future.The study was co-authored by NCAR researchers Flavio Lehner, Kyoko Ikeda, Martyn Clark, Andreas Prein, Changhai Liu, Mike Barlage and Roy Rasmussen. NCAR is sponsored by the National Science Foundation.
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Weather
| 2,018 |
August 2, 2018
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https://www.sciencedaily.com/releases/2018/08/180802141816.htm
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Radar better than weather balloon for measuring boundary layer
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Improving forecasting for a host of severe weather events may be possible thanks to a more comprehensive method for measuring the Earth's boundary layer depth, developed by Penn State researchers.
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The boundary layer is the layer of atmosphere that is closest to the Earth, less than one mile from the surface. Because it is the layer that is most affected by the convective heat from the Earth's surface, it is responsible for sudden weather shifts such as thunderstorms.The boundary layer gets its name because it traps things such as pollution, smog, smoke from forest fires, and other airborne particles from rising higher in the atmosphere. As sun warms the surface of the Earth, it also warms the air. This warm air rises, deepening the boundary layer.In research published in the In addition to being gathered in real time, radar measurements give a more complete analysis of the boundary layer by sending out vertical and horizontal impulses to log if snow, rain or insects are present.Inaccuracies in boundary layer assessment lead to significant errors in forecasts, said John Banghoff, graduate student in meteorology, Penn State. Banghoff said those inaccuracies are leading to poor forecasting results."If we can improve the accuracy of the initial information, that's going to get a better forecast in the future," Banghoff said. "Boundary layer estimates are off by a factor of two in most models, which is very significant. If you have 200 percent error in your model, it's not going to do a very good job."In addition to severe weather modeling, understanding boundary layer depth could improve models for air pollution and wildfire forecasting. A 2009 report by the National Research Council highlighted limitations of boundary layer depth monitoring as a major concern, citing that other monitoring methods should be explored.Researchers used the Weather Surveillance Radar-1988 Doppler (WSR-88D) radar in Central Oklahoma to test the ability of radars to assess boundary layer depth. Banghoff said the radars offered better spatial resolution than weather balloons and were just as accurate at predicting boundary layer depth, based on results of this research. These methods were also tested in eight different regions across the country, in locations such as Minnesota in February to Arizona in August, demonstrating the seasonal reliability of this method."We showed that the weather balloons, which are the baseline, compare pretty well with the radar observations. Once we found that the radar offered accurate information, we began using radar data to track boundary layer depth throughout the day."Researchers then plan to use this newly sourced radar data to fit into models, to see if the real-time data improves the models. They will use more than four years of archived data to further explore and refine the models.Warm air creates a cap on the atmosphere, trapping cooler air below. During severe weather events, Banghoff said, the air below will heat up and pierce that cap, creating massive cumulonimbus storm clouds.Banghoff said a similar phenomenon can be observed at the Earth's surface during fog events, where droplets of cool, moist air are trapped by the warmer air from above."It's kind of an obscure thing," Banghoff said. "People don't know what the boundary layer is but when you put it into context of wildfires and air pollution and severe storm forecasting then it has a lot of relevancy."
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Weather
| 2,018 |
August 2, 2018
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https://www.sciencedaily.com/releases/2018/08/180802102337.htm
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Heatwave and climate change having negative impact on our soil say experts
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The recent heatwave and drought could be having a deeper, more negative effect on soil than we first realised say scientists.
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This could have widespread implications for plants and other vegetation which, in turn, may impact on the entire ecosystem.That's because the organisms in soil are highly diverse and responsible not only for producing the soil we need to grow crops, but also other benefits such as cleaning water and regulating greenhouse gas emissions.The new study, led by researchers at The University of Manchester and published today (02/08/2018) in Due to climate change, disturbances such as drought are increasing in intensity and frequency. These extreme weather conditions change vegetation composition and soil moisture, which in turn impacts the soil's underlying organisms and microbial networks.By studying how microbes react to severe drought, the study provides a better understanding of how underground soil networks respond to such environmental disturbances.Lead author, Dr Franciska de Vries, from Manchester's School of Earth and Environmental Sciences, explains: "Soils harbour highly diverse microbial communities that are crucial for soil to function as it should."A major challenge is to understand how these complex microbial communities respond to and recover from disturbances, such as climate extremes, which are predicted to increase in frequency and intensity with climate change."These microbial communities within the soil play a crucial role in any ecosystem. But it wasn't known how soil networks respond to such disturbances until now."Sequencing of soil DNA for the study was conducted at the Centre for Ecology & Hydrology (CEH). Dr Robert Griffiths, a molecular microbial ecologist at CEH, said: "This study further identifies those key organisms affected by drought, which will guide future research to predict how future soil microbial functions are affected by climate change."The research team tested the effects of summer drought on plant communities consisting of four common grassland species. They found that drought increased the abundance of a certain fast-growing, drought-tolerant grass. With greater aboveground vegetation comes an increased rate of evapotranspiration, or cycling of water from plants to the atmosphere, lowering the overall soil moisture.Science conducted as part of Lancaster University's Hazelrigg grassland experiment was key to the findings.Professor Nick Ostle, from the Lancaster Environment Centre, said: "Our hot and dry summer this year is a 'wake up' to prepare for future weather stresses. We have just had the hottest ten years in UK history. This work shows that continued summer droughts will change soil biology. This matters as we plan for ensuring food security that depends on healthy soil."Unlike past research, this study considered the multitude of direct and indirect interactions occurring between different microbial organisms in soil. Rather than focusing on select attributes of bacteria and fungi, this research takes a comprehensive approach to studying soil ecosystems.Dr de Vries added: "This study allows soil ecologists to estimate the current and future impacts of drought on belowground organisms, helping to understand the complex interactions of species due to climate change."
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Weather
| 2,018 |
August 1, 2018
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https://www.sciencedaily.com/releases/2018/08/180801160044.htm
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Climate change-driven droughts are getting hotter, study finds
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Dry months are getting hotter in large parts of the United States, another sign that human-caused climate change is forcing people to encounter new extremes.
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In a study published today in "Available soil moisture can remove surface heat through evaporation, but if the land is dry, there is no opportunity to transport it away, which increases the local temperature," said lead author Felicia Chiang, a UCI graduate student in civil & environmental engineering. "Atmospheric conditions can influence soil, and we argue that they're shaping the temperatures we experience during droughts."UCI's research team analyzed observed temperature and precipitation data from the early and late 20th century and discovered that regions undergoing droughts warmed more than four times faster than areas in the southern and northeastern United States with average weather conditions. In addition, climate models showed a significant warming shift in Southern states between the late 20th century and early 21st century.These changes point to a greater number of droughts and heat waves co-occurring. This can lead to such calamities as wildfires and loss of crop yields. Widespread conflagrations, spurred on by abnormally high summer temperatures, are currently burning around the world, including in parts of California, Scandinavia and Greece."Heat waves and droughts have significant impacts on their own, but when they occur simultaneously, their negative effects are greatly compounded," said co-author Amir AghaKouchak, UCI associate professor of civil & environmental engineering and Earth system science. "Both phenomena, which are intensifying due to climate warming, are expected to have increasingly harmful consequences for agriculture, infrastructure and human health."He suggested that society has a responsibility to respond to the challenges presented by this new climate reality."The observed escalation in the number and intensity of wildfires is likely caused by the increase in frequency of hot droughts," AghaKouchak said. "We need to bolster our resiliency against these threats to protect our population health, food supply and critical infrastructure."
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August 1, 2018
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https://www.sciencedaily.com/releases/2018/08/180801093700.htm
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Arctic cyclone limits the time-scale of precise sea-ice prediction in Northern Sea Route?
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Climate change has accelerated sea-ice retreat in the Arctic Ocean. This has various negative impacts including acidification of ocean water and potential contribution to severe winters in mid-latitude regions. However, it has also opened up new opportunities for commercial maritime navigation in summer. The Northern Sea Route could reduce the navigational distance between Europe and Asia by about 40%, and accurate forecasting of sea-ice conditions has become a major research topic.
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A team of researchers led by National Institute of Polar Research (NIPR) and Hokkaido University, Japan, have now investigated an operational system in Norwegian Meteorological Institute for medium-range forecasting (up to 10 days ahead) of sea-ice thickness (SIT) in early summer in the East Siberian Sea, which is located on the Northern Sea Route. They reported on their work in The team studied the ability of the TOPAZ4 ice-ocean data system to help us to predict the distribution of SIT in this region. Since precise information is crucial for the operation of icebreaker vessels, it is needed to determine the lead time and accuracy of the forecast, and to assess how we could improve predictions in the future.Comparisons between TOPAZ4, other hindcast models, and sea-ice observations showed the system could reproduce the early-summer SIT distribution in the East Siberian Sea. The time-scale for accurate prediction of the SIT in this area was up to 3 days, with skill abruptly decreasing thereafter.The difficulties in predicting large-scale weather features could be a major factor in this decreased skill after 3 days. This unpredictability arises from the amplification of forecast error for features such as Arctic cyclones, so further work to improve the forecast skill for SIT in this region should focus on understanding the formation and development of these phenomena.Despite this unpredictability, the TOPAZ4 system was found to be reliable for early summer SIT prediction.We examined the model performance for a situation in July 2014, in which two vessels were blocked in the East Siberian Sea for about a week. Based on the vessel tracking data from AIS data, it was found that the vessel speed drastically decreases in the coastal area where thick sea ice (> 150 cm) is simulated, and the speed of the vessel was clearly negatively correlated with the simulated SIT during the entire passage. These results indirectly support the reliability of the daily mean SIT data from our simulation. More comprehensive analysis is needed based on the speed for a greater range of vessels. This will help to improve the potential of the method to help guide ships along the Northern Sea Route.
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July 31, 2018
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https://www.sciencedaily.com/releases/2018/07/180731164106.htm
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What is causing more extreme precipitation in northeastern U.S.?
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From Maine to West Virginia, the Northeast has seen a larger increase in extreme precipitation than anywhere else in the U.S. Prior research found that these heavy rain and snow events, defined as a day with about two inches of precipitation or more, have been 53 percent higher in the Northeast since 1996. A Dartmouth study finds that hurricanes and tropical storms are the primary cause of this increase, followed by thunderstorms along fronts and extratropical cyclones like Nor'easters. The findings are published in the
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"Our study provides insight into what types of extreme storms are changing and why. We found that hurricanes were responsible for nearly half of the increase in extreme rainfall across the Northeast. A warmer Atlantic Ocean and more water vapor in the atmosphere are fueling these storms, causing them to drop more rain over the Northeast," explains Jonathan M. Winter, an assistant professor of geography at Dartmouth and co-author of the study. "Other research has demonstrated that these two conditions have been enhanced in our warmer world," added Huanping Huang, a graduate student in earth sciences at Dartmouth and the study's lead author.The findings demonstrate that 88 percent of the extreme precipitation increase after 1996 was caused by large storms in Feb., March, June, July, Sept. and Oct.These results build on the team's earlier research by examining what caused the increase in heavier or extreme precipitation beginning in 1996. The researchers analyzed precipitation data from 1979 to 2016 across the Northeast -- Maine, New Hampshire, Vermont, Mass., Conn., R.I., N.J., N.Y., Pa., Md., DC, Del., and W.Va. in conjunction with data pertaining to daily weather maps and oceanic and atmospheric fields.
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July 30, 2018
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https://www.sciencedaily.com/releases/2018/07/180730120245.htm
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Australia facing extremely intense rain storms
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Landmark study shows how heavy, short rain storms are intensifying more rapidly than would be expected with global warming. Researchers say this is likely to lead to increasing flash floods and urban flooding.
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The team of international scientists, led by Dr Selma Guerreiro at the School of Engineering, Newcastle University, UK, has for the first time found increases in short, intense rain storms over Australia over the past 50 years.The storms are substantially larger than would be expected under climate change.Published today in Dr Selma Guerreiro, lead author, explains:"It was thought there was a limit on how much more rain could fall during these extreme events as a result of rising temperatures."Now that upper limit has been broken, and instead we are seeing increases in rainfall, two to three times higher than expected during these short, intense rainstorms."This does not mean that we will see this rate of increase everywhere. But the important thing now is to understand why rainfall is becoming so much more intense in Australia and to look at changes in other places around the world. How these rainfall events will change in the future will vary from place to place and depend on local conditions besides temperature increases."The paper shows future changes in short, intense rain storms might be being underestimated, with implications for flooding.Professor Seth Westra, co-author from the University of Adelaide, Australia, said:"These changes are well above what engineers currently take into account when determining Australia's flood planning levels or designing stormwater management and flood defence infrastructure."If we keep seeing this rate of change, we risk committing future generations to levels of flood risk that are unacceptable by today's standards."The authors recommend that a wide range of possible futures should be used to test existing and planned infrastructure, thus contributing to a robust adaptation to climate change.The team analysed changes in hourly and daily rainfall extremes, between 1990-2013 and 1966-1989, from 107 weather stations from all over Australia. While daily extremes can cause river flooding, hourly (and multi-hourly) extremes often cause urban flooding, flooding in small, steep rivers, and landslides.Between the two periods of analysis, global mean temperature increased by 0.48 °C. Because the amount of humidity that air can hold depends on the temperature (for each degree the atmosphere can hold around 6.5% more water), it was possible to calculate how much worse rainfall events could be expected to become.The observed increases in daily rainfall averaged over the whole Australian continent followed what would be expected for the current increases in warming. However, they are still within the bounds of what could be considered natural fluctuations of the climate and therefore cannot, at this point, be attributed to climate change.The hourly increases were 2 to 3 times higher than expected and even higher when looking just at the tropical north of Australia instead of the whole continent. These changes are outside what we would expect from natural fluctuations and could not be explained by changes in other factors like El Niño-Southern Oscillation or the seasonality of extreme rainfall. This research has shown that future hourly extreme rainfall cannot be projected using just temperature, but is a complex phenomenon that depends on many other atmospheric changes.
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July 26, 2018
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https://www.sciencedaily.com/releases/2018/07/180726161255.htm
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Europe may thrive on renewable energy despite unpredictable weather
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Researchers in Ireland, Switzerland, and the United Kingdom have shown how long-term weather patterns affect wind and solar renewable energy technologies across Europe. Using 30 years of meteorological data, the scientists have examined and further modelled the impact of renewable energy on the electricity sector out to the year 2030. The work suggests that despite the unpredictable nature of wind and solar energy, the European power system can comfortably generate at least 35% of its electricity using these renewables alone without major impacts on prices or system stability. The paper appears July 26 in the journal
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Wind and solar energy have exploded in popularity across Europe in the last decade as green alternatives to traditional carbon-based energy, quadrupling in use between 2007 and 2016. However, these technologies are not without their drawbacks -- both are susceptible to fluctuating weather patterns, raising concerns about Europe's ability to endure long spells with low winds or overcast skies. Researchers have used decades of historic weather data to model this variability in wind and solar energy and its effect on markets, but many studies only analyze data from one given year or focus solely on one country or small region.The researchers challenge both the temporal and spatial limitations of previous studies by analyzing electricity system operation across Europe -- including power transmission between countries and technical operational constraints -- using wind and solar data spanning the 30-year period from 1985 to 2014. By uncovering trends from this longstanding data trove across a vast, interconnected region, the team was able to model how Europe would fare under five different renewable energy scenarios with varying sustainability ambitions 12 years into the future. It turns out that the breadth and depth of their data pool made all the difference when it came to understanding trends in CO2 emissions, system costs, and system operation -- all of which are essential to the effective development of energy policy."When planning future power systems with higher levels of wind and solar generation, one year of weather data analysis is not sufficient," says says Seán Collins, a researcher at MaREI, the Centre for Marine and Renewable Energy Ireland at the Environmental Research Institute in University College Cork. "We find that single-year studies could yield results that deviate by as much as 9% from the long-term average at a European level and even more at a country level. When there are legally binding targets on carbon emissions and the share of renewable energy, or promises to avoid sharp price hikes, this makes all the difference."By using multiple years to better understand the way other variables respond as wind and solar energy penetrate the market, Collins and his team found that CO2 emissions and total energy generation costs fluctuate wildly in future scenarios. These can become up to five times more uncertain as weather-dependent resources gain greater traction in the market. However, they also found that Europe could withstand this variability quite well thanks to its close integration -- their models estimate Europe could use renewables for more than two-thirds of its electricity by 2030, with more than one-third coming from wind and solar.Collins and his team believe their models and data could be used to depict a variety of possible future scenarios to help policymakers better understand the reliability and impact of renewable energy, including the impacts of a shift to 100% renewable electricity systems. By making their models and data openly available, the researchers also hope that future work will demonstrate greater awareness of these long-term weather patterns in order to accurately depict a more renewable-energy-reliant world."For future policy developments to be robust and to capture the meteorological dependency of decarbonised energy systems, they should be based on open modeling analyses that utilise common long-term datasets," says Collins.
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July 26, 2018
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https://www.sciencedaily.com/releases/2018/07/180726085759.htm
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New clues to origins of mysterious atmospheric waves in Antarctica
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Two years after a CIRES and CU Boulder team discovered a previously unknown class of waves rippling continuously through the upper Antarctic atmosphere, they've uncovered tantalizing clues to the waves' origins. The interdisciplinary science team's work to understand the formation of "persistent gravity waves" promises to help researchers better understand connections between the layers of Earth's atmosphere -- helping form a more complete understanding of air circulation around the world.
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"A big picture of Antarctic gravity waves from the surface all the way to the thermosphere is emerging from the studies, which may help advance global atmospheric models," said CIRES Fellow and CU Boulder Professor of Aerospace Engineering Sciences Xinzhao Chu, lead author of the new study published today in the "The new understanding results from a series of journal publications, based on multiple years of lidar observations, many made by winter-over students, from Arrival Heights near McMurdo Station in Antarctica."In the 2016 paper, Chu and her colleagues discovered persistent gravity waves: huge ripples that sweep through the upper atmosphere in 3- to 10-hour periods. And now, by combining observations, theory, and models, they propose two possible origins of those waves: they are either from lower-level waves breaking and re-exciting new waves higher in the sky, and/or from polar vortex winds.Since 2016, the team managed to track the origin of the upper atmospheric waves down to the lower-altitude stratosphere. The team then characterized the dominant gravity waves there, but found they had very different properties than the persistent waves in the upper atmosphere."The upper-atmosphere waves are huge, with a horizontal length of around 1,200 miles (2,000 km), and the lower, stratospheric waves are much smaller -- only 250 miles (400 km)," said Jian Zhao, a Ph.D. candidate in CU Aerospace, working in Chu's group, who stayed the 2015 winter over at McMurdo for lidar observations.Zhao and colleagues previously described the stratospheric waves in an earlier study, and he is second author on the new study which describes how the wave energy varies over seasons and years -- documenting those kinds of variations is critical for researchers trying to understand how the waves influence things like global air circulation and climate change.The team suspects that when these lower, smaller-scale stratospheric gravity waves break, they trigger the formation of the huge waves that then travel to the upper atmosphere through a process called "secondary wave generation."Evidence from lidar data at McMurdo station pointing to this process was described in a paper published this year, led by Sharon Vadas, a researcher from Northwest Research Associates, and colleagues."It's similar to ocean waves breaking on a beach," said Vadas. "When the wind flows downslope from the mountains near McMurdo, the excited mountain waves travel upward in the atmosphere, growing larger and larger until they break over huge scales, creating these secondary gravity waves."Understanding the origins of the waves relied on Vadas' theory of secondary gravity waves and a global, high-resolution model created by Erich Becker at the Leibniz Institute of Physics in Germany. Becker's model perfectly stitches together the theory and lidar observations. It suggests that secondary wave formation is particularly persistent during winter, and that it occurs not only at McMurdo Station, but at mid to high latitudes in both hemispheres.Another possible source of the persistent waves is the polar vortex -- a persistent pattern of wind and weather that rotates around the South Pole during winter, Chu and her colleagues reported in the latest paper."The fast vortex winds could either modify the waves as they move upward, or the winds could actually generate waves themselves," said Lynn Harvey, a coauthor on the study, and researcher at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder. "With more observations, we should be able to determine which scenario is true."Chu and her research colleagues sometimes find themselves sitting at desks running computer models and calculations, and sometimes they are bundled head-to-toe, walking through strong winds and frigid temperatures well-below zero degrees F in Antarctica to run cutting edge lidar systems installed there.The National Science Foundation-managed U.S. Antarctic Program and the Antarctica New Zealand program have supported the team's work in Antarctica for eight years, starting with the installation of Chu's custom-built lidar systems, which allows her team to probe the most difficult-to-observe regions of the atmosphere. Studying atmospheric waves near the South Pole is critical to improving climate and weather models, and forming a better picture of global atmospheric behavior."We still have many unanswered questions," said Chu. "But in about five years, using a combination of observations and high-resolution modelling, we hope to resolve these mysteries."Two of her students -- recent graduate Ian P. Geraghty and Ph.D. student Zimu Li -- will travel to Antarctica this October to continue the research.
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July 23, 2018
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https://www.sciencedaily.com/releases/2018/07/180723143002.htm
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Cold wave reveals potential benefits of urban heat islands
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The concrete and asphalt that make city summers brutally hot might not be a bad thing during winter's deep freeze.
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Researchers from Princeton University have found that the urban heat island effect -- cities are hotter in the summer than their surrounding areas -- also helps keep cities warmer during extreme cold. The findings have implications for urban planners in areas such as New York City or Chicago, which experience marked seasonal temperature swings.Jiachuan Yang, a post-doctoral researcher, and Elie Bou-Zeid, a professor of civil and environmental engineering, analyzed urban temperatures in 12 U.S. cities in the Northeast and Midwest during a 2014 cold wave. They found that urban areas stayed warmer than the surrounding suburbs and country. The difference in temperature was greatest during the cold wave, which set more than 49 low-temperature records. The temperatures differences were also more pronounced at night than during the day.The findings, reported in the June issue of the Urban heat islands have been extensively studied during heat waves, with recent analyses showing city temperature boosts can be as high as 8 degrees Fahrenheit for large cities like New York City or Washington. Yang and Bou-Zeid's study is among the first to examine the phenomenon during cold waves. Yang said that for some areas, cold extremes will continue to pose a challenge even as the climate warms. "More weather-related mortality worldwide is attributed to exposure to excessive cold than to excessive heat, and global warming is unlikely to change this reality," he said.The researchers combined temperature and land use data with high-resolution weather simulations to investigate the 2014 cold wave in Chicago. The results suggested that heat released from buildings was a key contributor to the stronger heat island effect observed during the cold wave."When you heat buildings, the heat is going to be released from the buildings and go out into the urban environment," Yang said. In the city, skyscrapers create street canyons that trap heat, while in rural areas heat from buildings dissipates more rapidly into the surroundings. During cold waves, street canyons help cities reduce heating demand and make being outdoors more tolerable, Yang said.During the cold wave, Yang and Bou-Zeid also found an enhanced difference in the amount of heat released at night in the city compared to rural areas. Their simulations showed this was due to the city's thermal battery function -- concrete and other engineered materials' ability to store more heat than soils, and to discharge this heat when temperatures drop. Colder nighttime temperatures appeared to stimulate heat exchange.Many cities are working on ways to mitigate summer heat. These include installing cool roofs, which are covered with light-reflecting materials; and green roofs, which are covered with plants that reduce temperatures by evaporative cooling when moisture is released into the air. The researchers modified their simulation to test the effects of cool roofs and green roofs on the urban heat island during a cold wave. They found that cool roofs reduced daytime temperatures, while green roofs led to a small increase in daytime temperatures and a somewhat larger reduction in nighttime temperatures, due to the lower heat storage capacity of soils compared to traditional building materials.Dan Li, an assistant professor at Boston University, said the work offers lessons for planners. "This work highlights the fact that we need to consider the seasonal variability of urban heat islands and assess the associated hazards and benefits in a comprehensive way," said Li, who conducted doctoral and post-doctoral research with Bou-Zeid but was not involved in the present study.Both Chicago and New York City are pursuing ambitious climate action plans, which include the promotion of cool roofs and green roofs to reduce the urban heat island effect. Yang said it remains important to combat summer heat, but cities should not ignore the risks of extreme cold when planning mitigation efforts.As a potential solution, Bou-Zeid's group is collaborating with materials expert Anna Laura Pisello and her lab at the University of Perugia in Italy on studies of new color-changing building materials that could ease summer heat while keeping cities warmer in the winter. Yang is also applying the models developed in this study to explore the most effective spatial arrangements for heat island mitigation strategies within a city.This work was supported by the National Science Foundation.
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July 23, 2018
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https://www.sciencedaily.com/releases/2018/07/180723142837.htm
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Warming temperatures could increase suicide rates across the US and Mexico
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Suicide rates are likely to rise as the earth warms, according to new research published July 23 in
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"When talking about climate change, it's often easy to think in abstractions. But the thousands of additional suicides that are likely to occur as a result of unmitigated climate change are not just a number, they represent tragic losses for families across the country," said Burke, assistant professor of Earth system science in the School of Earth, Energy & Environmental Sciences at Stanford.Researchers have recognized for centuries that suicides tend to peak during warmer months. But, many factors beyond temperature also vary seasonally -- such as unemployment rates or the amount of daylight -- and up to this point it has been difficult to disentangle the role of temperature from other risk factors."Suicide is one of the leading causes of death globally, and suicide rates in the U.S. have risen dramatically over the last 15 years. So better understanding the causes of suicide is a public health priority," Burke said.To tease out the role of temperature from other factors, the researchers compared historical temperature and suicide data across thousands of U.S. counties and Mexican municipalities over several decades. The team also analyzed the language in over half a billion Twitter updates or tweets to further determine whether hotter temperatures affect mental well-being. They analyzed, for example, whether tweets contain language such as "lonely," "trapped" or "suicidal" more often during hot spells.The researchers found strong evidence that hotter weather increases both suicide rates and the use of depressive language on social media."Surprisingly, these effects differ very little based on how rich populations are or if they are used to warm weather," Burke said.For example, the effects in Texas are some of the highest in the country. Suicide rates have not declined over recent decades, even with the introduction and wide adaptation of air conditioning. If anything, the researchers say, the effect has grown stronger over time.To understand how future climate change might affect suicide rates, the team used projections from global climate models. They calculate that temperature increases by 2050 could increase suicide rates by 1.4 percent in the U.S. and 2.3 percent in Mexico. These effects are roughly as large in size as the influence of economic recessions (which increase the rate) or suicide prevention programs and gun restriction laws (which decrease the rate)."We've been studying the effects of warming on conflict and violence for years, finding that people fight more when it's hot. Now we see that in addition to hurting others, some individuals hurt themselves. It appears that heat profoundly affects the human mind and how we decide to inflict harm," said Solomon Hsiang, study co-author and associate professor at theUniversity of California, Berkeley.The authors stress that rising temperature and climate change should not be viewed as direct motivations for suicide. Instead, they point out that temperature and climate may increase the risk of suicide by affecting the likelihood that an individual situation leads to an attempt at self-harm."Hotter temperatures are clearly not the only, nor the most important, risk factor for suicide," Burke emphasized. "But our findings suggest that warming can have a surprisingly large impact on suicide risk, and this matters for both our understanding of mental health as well as for what we should expect as temperatures continue to warm."
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July 19, 2018
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https://www.sciencedaily.com/releases/2018/07/180719142115.htm
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In a warming climate, Arctic geese are rushing north
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As Arctic temperatures continue to rise, migratory barnacle geese have responded by speeding up their 3,000-kilometer migration in order to reach their destination more quickly with fewer stops along the way, according to new evidence reported in
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As a result of this recovery period, barnacle goose chicks continue to hatch too late to take advantage of early spring foraging opportunities. The new study shows that fewer of them are surviving long enough to leave their mothers' sides and make the trek on their own. The findings suggest that the birds are in trouble unless they start heading north for the Arctic earlier in the year, as opposed to speeding up their travel along the way, the researchers say."The birds are leaping in the dark as they cannot predict, while being at the wintering grounds in temperate areas, whether it is going to be an early or late spring in the Arctic," says Bart Nolet of the Netherlands Institute of Ecology and University of Amsterdam. "The weather systems in the temperate and Arctic regions are not linked, and on top of that, temperature rise is far stronger in the Arctic than in the temperate region. Only halfway through the migration, the geese are probably able to judge from environmental cues what spring will be like up in the Arctic, and they are apparently able to speed up if spring is early."The researchers, including first author and recent graduate of the Nolet lab Thomas Lameris, combined remote sensing, bird tracking, stable isotope techniques, and field observations along the birds' entire flyway to explore the effect of climate warming on migration and breeding times of barnacle geese. The geese travel every spring from their temperate wintering and staging grounds along the North Sea coast via stopover sites along the Baltic Sea and Barents Sea to their breeding grounds in the Russian Arctic.The evidence shows that egg laying has advanced much less than the birds' arrival in the Arctic because the geese must take time after their arrival to refuel. In years when spring came early, the geese laid their eggs well after the snow began to melt. As a result, there was a mismatch between the time that their goslings hatched and peak food quality. In years with a larger mismatch, the researchers report, goslings experienced reduced survival in the month after hatching.The researchers say that the geese can only fully adapt to the rapid warming of the Arctic when they find ways to depart earlier from their wintering grounds. Currently, Nolet adds, barnacle geese most likely rely heavily on cues like day length that aren't changing with the temperature rise. They might also depend on other cues, including the greening of vegetation, that aren't advancing as fast in the temperate region as they are in the Arctic.Whether these migrants can adapt their cue sensitivity and match their migration timing to changing climatic conditions remains uncertain. But there are signs that the geese may be flexible enough to adjust by other means. In fact, Nolet said that some barnacle geese have recently given up migration, breeding instead in the temperate region."Geese migrate in families, and young learn the route and timing from their parents," Nolet says. "On the one hand, this leads to traditional patterns; on the other hand, it can lead to rapid adjustments when some birds experience that doing the migration differently -- often induced by extreme weather events -- pays off."Through comparisons of the migratory and non-migratory geese, his team hopes to learn more about the costs and benefits of migration.Financial support was provided by the Netherlands Organisation for Scientific Research and a Marie Curie Intra-European Fellowship.
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July 19, 2018
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https://www.sciencedaily.com/releases/2018/07/180719112217.htm
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Scientists use satellites to measure vital underground water resources
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The availability of water from underground aquifers is vital to the basic needs of more than 1.5 billion people worldwide, including those of us who live in the western United States. In recent decades, however, the over-pumping of groundwater, combined with drought, has caused some aquifers to permanently lose essential storage capacity.
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With the hope of providing water resource managers with better tools to help keep aquifers healthy, a team of scientists from ASU and the Jet Propulsion Laboratory (JPL) are using the latest space technology to look underneath Earth's surface to measure this precious natural resource.They've focused their efforts on one of the world's largest aquifer systems, located in California's Central Valley, measuring both its groundwater volume and its storage capacity. The results of their most recent findings in this ground breaking study have been recently published in California's Central Valley is a major agricultural hub covering an area of about 20,000 square miles. It produces more than 25 percent of U.S. agriculture, at an estimated value of $17 billion per year.Beyond agricultural crops, the Central Valley aquifer system provides necessary water for people and wetlands, supplying about 20 percent of the overall U.S. groundwater demand. With a combination of population increases and drought, this aquifer is ranked one of the most stressed aquifer systems in the world.While past studies on water resources and drought have focused mainly on low-resolution or local scale measurements of groundwater dynamics, the research team for this study, which includes ASU School of Earth and Space Exploration scientists Chandrakanta Ojha, Manoochehr Shirzaei, and Susanna Werth, with Donald Argus and Thomas Farr from JPL, went an even more high-tech route.They used the data collection features of several satellite-based Earth remote sensing techniques to get a more consistent and higher resolution view of California's Central Valley aquifer system than has ever been done before."Ironically," says co-author Werth, who also has a joint appointment at the ASU School of Geographical Sciences and Urban Planning, "we had to go several hundreds of miles up into space to see what was going on under the surface of our planet."Using these high-tech remote sensing techniques, the team analyzed data from the 2007 to 2010 drought period and began to map the entire California Central Valley."It's great when we can use our high-tech Earth-orbiting satellites to help solve real-world problems in California," adds co-author Farr of the Jet Propulsion Laboratory.They measured land subsidence (when land above and around an aquifer shifts downward) using space-borne Interferometric Synthetic Aperture Radar (InSAR) and added that to data on groundwater levels sampled at thousands of wells across the Central Valley."It's this combination of literally terabytes of data that helps us get the best picture of what is happening below the surface," says lead author Ojha.From this analysis, the team found that between 2007 and 2010, there was a significant drop in ground levels in the southern area of the Central Valley. In fact, in a three-year period, there was a drop of nearly 32 inches, a decline that should normally take decades."Groundwater overdraft in some parts of the Central Valley has permanently altered clay layers, causing rapid ground sinking that can be measured by radar satellites from space," says co-author Shirzaei.The most startling result of this study, however, is the permanent loss of water storage capacity in the aquifer system. During the 2007 to 2010 drought, up to two percent of storage capacity was lost entirely when the water level declined and the clay layers in the system were permanently compacted."That storage capacity cannot be recovered through natural recharge," says Ojha. "This means that during the wet season, when the Central Valley gets rain, there is less space to store it, making groundwater supplies scarcer during future droughts."The next steps for this team will be to focus on the period of drought in California from 2012 to 2016, which was even more detrimental to the Central Valley aquifer than the 2007 to 2010 drought period."Periods of drought have long-term effects on groundwater supplies and create major challenges for groundwater management," says Maggie Benoit, a program director in the National Science Foundation's Division of Earth Sciences, which provided funding for the research. "Now researchers are developing new methods for monitoring groundwater levels using satellite-based measurements of Earth's surface, providing a more comprehensive picture of the health of our nation's groundwater."The researchers plan to integrate radar measurements with additional data from the newly launched NASA/GFZ GRACE Follow-On (GRACE-FO) satellites. The GRACE FO mission, which launched on May 22, consists of two nearly identical satellites that follow one another along the same orbit. The satellites continually measure the distance between them, which changes depending on the gravity field over which they are orbiting. Since oscillations of groundwater change the gravity field, scientists can use the data to map underground water location and volume change.And the work will not end there. The research team hopes to extend the research they are doing in California to Arizona and other areas of the arid southwest."The whole region is affected by a long-term drought," states Werth, "with differences in severity, climate conditions, groundwater geology and water management approaches. Our hope is that these studies will enable authorities and decision makers to accurately manage water resources and plan for future water allocations. Water managers need to know about the irreversible processes taking place and how to act to prevent a future crisis."
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July 17, 2018
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https://www.sciencedaily.com/releases/2018/07/180717155157.htm
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Scientists recover possible fragments of meteorite that landed in marine sanctuary
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The largest recorded meteorite to strike the United States in 21 years fell into NOAA's Olympic Coast National Marine Sanctuary, and researchers have recovered what are believed to be pieces of the dense, interstellar rock after conducting the first intentional hunt for a meteorite at sea.
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The golf cart-sized meteorite, which fell into the sanctuary on March 7 around 7:15 pm PST and about 15 miles off the Washington coast, broke into many pieces before it hit the water. Its cosmic burst, picked up by NOAA's NEXRAD weather radar, created a giant fireball called a Scientists from NOAA, NASA and the Ocean Exploration Trust worked with theDr. Marc Fries, NASA's curator of cosmic dust, said the search -- which included the use of a specially designed Based on radar data, the meteorite weighed two tons with fragments as large as 10 pounds. Suspected fragments of the meteorite are scattered over an area in the southwest part of the sanctuary near the rim of Quinault Canyon.After passing through the atmosphere, about 1,415 pounds of the space rock fell into the sanctuary -- larger than the 2003 Park Forest, Illinois, meteorite, which had held the record for the largest meteorite to hit the U.S. Until now.The fragments collected will be analyzed further to confirm they are meteorite material and then shipped to the Smithsonian Museum of Natural History in Washington, D.C., to potentially become part of their collection.
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July 17, 2018
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https://www.sciencedaily.com/releases/2018/07/180717094705.htm
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How does the sun's rotational cycle influence lightning activity on earth?
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A collaborative research team in Japan has taken the first steps to understanding how the sun's rotational cycle influences lightning activity. They found answers in an unusual source -- diaries dating back to the 1700s.
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The research was published in the The team includes faculty members from several universities in Japan, as well as Ryuho Kataoka, an associate professor of the National Institute of Polar Research (NIPR). NIPR supports scientific research and observation of the polar regions and is associated with the Research Organization of Information and Systems (ROIS) in Japan."It is well known that long-term -- centennial to millennial-scale -- variations of solar activity influences terrestrial climate," said Hiroko Miyahara, first author on the paper, and an associate professor of Humanities and Sciences/Museum Careers at Musashino Art University in Tokyo, Japan. "However, it is not well established whether the sun influences the daily or monthly weather."Miyahara points to the 27-day solar rotational period, which is the average time it takes for the sun to rotate on its axis. Since the sun consists of plasma, the equator rotates quicker than its poles. When areas of high activity, such as sunspots, face Earth, there's an increase in ultraviolet rays and decrease in energetic particles showering the atmosphere.Miyahara and her team set out to clarify if the 27-day cycle was reflected in meteorological phenomena, such as lightning activity on Earth. They turned to a set of diaries kept continuously for more than 150 years. A farm family in Hachioji (currently located in western part of Tokyo) kept the first diary called the, "Diary of Ishikawa Family," while the other is the, "Diary of Hirosaki Clan Government Office," a detailed log kept by a collective of civil servants from Hirosaki (currently located in the Aomori Prefecture) who were in residence in central Tokyo. The two locations are about 25 miles apart.The researchers examined the records for mentions of thunder and lightning events between May and September, when the influence from the cold Siberian air mass is weak in Japan.They found peaks of lightning and thunder activity every 24 to 31 days, the same time window it takes the sunspots to rotate completely. It's a strong signal, especially when the yearly-average number of sunspots is high."The cyclic behavior of the sun is playing a very important role in the changes of weather in Japan," Miyahara said, noting that the rhythm of lightning activity amplifies as the level of solar activity increases.Next, the team plans to study the detailed mechanism of the solar influence on meteorological events and analyze how the impact of solar activity might propagate to Japan."Our ultimate goal is to include the influence of solar activity in the weather forecast," Miyahara said. "It would improve the accuracy of the forecast, and it may even enable a longer-term weather forecast."
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Weather
| 2,018 |
July 12, 2018
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https://www.sciencedaily.com/releases/2018/07/180712141622.htm
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Growth rates of loblolly pine trees
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The ability to predict weather patterns has helped us make clothing choices and travel plans, and even saved lives. Now, researchers in Virginia Tech's College of Natural Resources and Environment are using similar predictive methods to forecast the growth of trees.
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In a study published in The paper brings together efforts from two projects funded by the U.S. Department of Agriculture. In the first, known as PINEMAP, hundreds of researchers collected forest growth data from the past 35 years and developed mathematical models to quantify how pine forests may respond to climate change.The second project, led by R. Quinn Thomas, assistant professor of forest dynamics and ecosystem modeling in Virginia Tech's Department of Forest Resources and Environmental Conservation, focused on quantifying uncertainties in how climate models predict how forest and agricultural ecosystems, along with decisions like the timing of crop or forest harvest rotations, influence climate temperature and precipitation patterns.Thomas noticed similarities between these two projects and the way weather data can help meteorologists predict future weather patterns. This led him to develop a new research project to forecast forest productivity through the middle of the 21st century."I realized that we could use the past to inform the future," Thomas said. "Historical observations on tree growth and weather can be fed into a mathematical model describing how forests grow, making it more accurate over time. This is similar to how weather forecasts are updated as new weather data becomes available."Thomas and team members from his department -- master's student Annika Jersild, postdoctoral associate Evan Brooks, Associate Professor Valerie Thomas, and Professor Randolph Wynne -- built on data and concepts from the two projects to develop a common analytical framework that can be combined with predictions from climate models to produce an outlook for the future.Data on the diameter of trees, the number of leaves produced in a given year, and how much water is evaporated from the forest are all fed into a model representing the process of forest growth. Then, using statistical methods similar to those used in weather forecasting, the model is adjusted based on those data to account for uncertainties."This new study allows us to put a level of certainty or uncertainty on those estimates, so we're able to say 'there is an 80-percent chance that the forest will grow faster over the next few decades,'" explained Thomas, who is also affiliated with the Global Change Center housed in Virginia Tech's Fralin Life Science Institute.Researchers looked specifically at conditions in the Southeastern United States, often referred to as the "wood basket of the United States" for its productive forests. They focused their attention on planted loblolly pine plantations, an important source of timber for the region."We found that in this region, there will be about a 30-percent increase in productivity between now and the middle of the century," Thomas said.He cautioned, however, that there is uncertainty around those predictions, depending on specific parts of the region."The largest gains are forecasted in Virginia, and there's high confidence that we'll see that increase in productivity there. In Florida, however, the increase in productivity is expected to be lower, and we may even see a decline in productivity between now and mid-century," he explained.Despite these uncertainties, however, the future of ecological forecasting looks bright."I'm excited to see how this particular forecast does over the next few decades and to update it as we learn more about how forests work and as more data become available," Thomas said. "Furthermore, this system sets a foundation for this process to be used in the forestry industry to predict other aspects besides productivity. Beyond that, the study is an example of how ecological scientists are starting to think about becoming forecasters in a way similar to how we've been forecasting the weather, and that's very exciting."
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Weather
| 2,018 |
July 9, 2018
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https://www.sciencedaily.com/releases/2018/07/180709202909.htm
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Grasslands more reliable carbon sink than trees
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Forests have long served as a critical carbon sink, consuming about a quarter of the carbon dioxide pollution produced by humans worldwide. But decades of fire suppression, warming temperatures and drought have increased wildfire risks -- turning California's forests from carbon sinks to carbon sources.
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A study from the University of California, Davis, found that grasslands and rangelands are more resilient carbon sinks than forests in 21st century California. As such, the study indicates they should be given opportunities in the state's cap-and-and trade market, which is designed to reduce California's greenhouse gas emissions to 40 percent below 1990 levels by 2030.The findings, published July 10 in the journal "Looking ahead, our model simulations show that grasslands store more carbon than forests because they are impacted less by droughts and wildfires," said lead author Pawlok Dass, a postdoctoral scholar in Professor Benjamin Houlton's lab at UC Davis. "This doesn't even include the potential benefits of good land management to help boost soil health and increase carbon stocks in rangelands."Unlike forests, grasslands sequester most of their carbon underground, while forests store it mostly in woody biomass and leaves. When wildfires cause trees to go up in flames, the burned carbon they formerly stored is released back to the atmosphere. When fire burns grasslands, however, the carbon fixed underground tends to stay in the roots and soil, making them more adaptive to climate change."In a stable climate, trees store more carbon than grasslands," said co-author Houlton, director of the John Muir Institute of the Environment at UC Davis. "But in a vulnerable, warming, drought-likely future, we could lose some of the most productive carbon sinks on the planet. California is on the frontlines of the extreme weather changes that are beginning to occur all over the world. We really need to start thinking about the vulnerability of ecosystem carbon, and use this information to de-risk our carbon investment and conservation strategies in the 21st century."The study ran model simulations of four scenarios:The only scenario where California's trees were more reliable carbon sinks than grasslands was the first one, which requires even more aggressive global greenhouse gas reductions than the Paris Climate Agreement. The current path of global carbon emissions reveals grasslands as the only viable net carbon dioxide sink through 2101. And grasslands continue to store some carbon even during extreme drought simulations.The model results can help guide "climate-smart" options for maintaining carbon sinks in natural and working lands in California. Ranchers are beginning to use innovative management approaches to improve carbon storage, which can further boost the ability of grasslands to store carbon in the future.The study does not suggest that grasslands should replace forests on the landscape or diminish the many other benefits of trees. Rather, it indicates that, from a cap-and-trade, carbon-offset perspective, conserving grasslands and promoting rangeland practices that promote reliable rates of carbon sequestration could help more readily meet the state's emission-reduction goals.As long as trees are part of the cap-and-trade portfolio, protecting that investment through strategies that would reduce severe wildfire and encourage drought-resistant trees, such as prescribed burns, strategic thinning and replanting, would likely reduce carbon losses, the authors note. But the study itself did not consider in its models forest management strategies that reduce wildfire threats.Since 2010, about 130 million trees have died in California forests due to high tree densities combined with climate change, drought and bark beetle infestation, the U.S. Forest Service reports. Eight of the state's 20 most destructive fires have occurred in the past four years, with the five largest fire seasons all occurring since 2006."Trees and forests in California are a national treasure and an ecological necessity," Houlton said. "But when you put them in assuming they're carbon sinks and trading them for pollution credits while they're not behaving as carbon sinks, emissions may not decrease as much as we hope."The study was funded by the National Science Foundation.
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Weather
| 2,018 |
July 5, 2018
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https://www.sciencedaily.com/releases/2018/07/180705100406.htm
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A bird's eye view of the Arctic
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Drones and other unmanned technologies can cost-effectively collect weather data in harsh or remote environments and contribute to better weather and climate models, according to a new study from CIRES and NOAA researchers. Unmanned aircraft and instrument-bearing tethered balloons are helping fill in critical data gaps over difficult-to-sample surfaces in the Arctic, including newly forming sea ice and partially frozen tundra.
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"We're showing that we have the ability to deploy unmanned aircraft and tethered balloon systems routinely in a very harsh environment for targeted field campaigns. We're also supporting development efforts to make these technologies available to the broader scientific community," said Gijs de Boer, a CIRES researcher working in the NOAA Earth System Research Laboratory and lead author of the paper, published June 29 in the Communities, businesses, and governments around the world need accurate and timely weather and climate forecasts for planning and safety. One key to improving forecast models is obtaining additional data, especially lacking in remote locations such as the Arctic. This research, a collaboration between CIRES and NOAA scientists, along with United States Department of Energy (DOE) and university partners, was designed to investigate whether drones and other unmanned technologies can complement and enhance more conventional ways of gathering atmospheric data.In the new study, the researchers find that unmanned aircraft and tethered balloon systems -- collectively known as unmanned aircraft systems or UASs -- can help fill data gaps and are well-suited for routine flights in the Arctic. And because of the work done by DOE's Atmospheric Radiation Measurement (ARM) user facility, in partnership with de Boer and his colleagues to develop these state-of-the-art unmanned technologies, ARM is now accepting proposals from atmospheric scientists to deploy UASs at their research sites.Since 1997, the ARM user facility has collected measurements of clouds, aerosols, atmospheric state, and radiation at their North Slope of Alaska observatory near Utqia?vik (formerly Barrow). Additional measurements have been taken at Atqasuk (approximately 60 miles inland from Utqia?vik) and Oliktok Point (another coastal site, 165 miles to the southwest of Utqia?vik). These observatory-based measurements have helped scientists better understand the Arctic natural system.When ground-based, stationary instruments take measurements, those observations are limited to that location or a scanning instrument's field of view. Unmanned aircraft or tethered balloons can take measurements over much larger areas. Recognizing the potential of UAS observations, the DOE fostered acceleration of scientific UAS field deployments in the Arctic in starting in 2015."The surface around ARM's North Slope sites is highly heterogeneous, so the information that these technologies can provide is extremely valuable to understand what impact the varied surface is having on atmospheric properties," said James Mather, ARM technical director.In a series of campaigns, de Boer and his colleagues along with ARM staff members flew various unmanned aircraft, and ARM staff from Sandia National Laboratory launched tethered balloons, demonstrating increasingly more advanced and miniaturized measurement capabilities -- including NOAA's Printed Optical Particle Spectrometer, or POPS -- while expanding operations to harsher Arctic conditions. Together, these UASs provide detailed profiles of atmospheric properties -- including thermodynamics, winds, radiation, aerosols, cloud microphysics -- that provide a more comprehensive understanding of the Arctic's lower atmosphere.Because they're taken in situ, or at the location of interest, atmospheric measurements taken with unmanned aircraft systems can better represent local conditions, and feeding those observations into weather or climate models makes the models more accurate. "With balloons and unmanned aircraft, we get a different perspective," said de Boer. "We can cover larger areas and get a distribution, for example, of temperature variability around a site. With UASs we can sample across a model's grid box instead of at a single point, and that's important for model development."In addition to his Arctic research, de Boer is the organizer of this year's annual gathering of an international community using UAS for atmospheric research known as ISARRA, short for the International Society for Atmospheric Research using Remotely piloted Aircraft. Following a week-long conference at the University of Colorado in Boulder, over a hundred scientists, engineers and aircraft pilots will regroup for a week of science flights in southern Colorado's San Luis Valley.De Boer, along with CIRES, NOAA, and ARM colleagues, will head back to Alaska's North Slope later this summer for another field campaign. As part of the World Meteorological Organization's and the World Climate Research Programme's Year of Polar Prediction, the researchers will use unmanned aircraft and tethered balloons to observe and model the Arctic lower atmosphere at the DOE Oliktok Point site. They're also teaming up with the University of Alaska Fairbanks and partners to take UAS measurements over the Arctic Ocean to better understand how wind influences ocean mixing.
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Weather
| 2,018 |
July 3, 2018
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https://www.sciencedaily.com/releases/2018/07/180703141439.htm
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In a warming world, could air conditioning make things worse?
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As climate change continues to push summer temperatures ever higher, the increased use of air conditioning in buildings could add to the problems of a warming world by further degrading air quality and compounding the toll of air pollution on human health, according to a new study.
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Writing today (July 3, 2018) in a special climate change issue of the journal "What we found is that air pollution will get worse," explains David Abel, the lead author of the new report and a UW-Madison graduate student in the Nelson Institute for Environmental Studies' Center for Sustainability and the Global Environment. "There are consequences for adapting to future climate change."The analysis combines projections from five different models to forecast increased summer energy use in a warmer world and how that would affect power consumption from fossil fuels, air quality and, consequently, human health just a few decades into the future.In hot summer weather, and as heat waves are projected to increase in frequency and intensity with climate change, there is no question that air conditioning does and will save lives, says Jonathan Patz, a senior author of the study and a UW-Madison professor of environmental studies and population health sciences.However, he cautions that if the increased use of air conditioning due to climate change depends on power derived from fossil fuels, there will be an air quality and human health tradeoff. "We're trading problems," says Patz, an expert on climate change and human health. "Heat waves are increasing and increasing in intensity. We will have more cooling demand requiring more electricity. But if our nation continues to rely on coal-fired power plants for some of our electricity, each time we turn on the air conditioning we'll be fouling the air, causing more sickness and even deaths."Another senior author of the new "Air quality is a big issue for public health," she explains, noting that increases in ground-level ozone and fine particulate matter in the air -- byproducts of burning fossil fuels and known hazards to human health -- will be one result of adding to fossil-fuel power consumption.The study forecasts an additional 13,000 human deaths annually caused by higher summer levels of fine particulate matter and 3,000 caused by ozone in the Eastern U.S. by mid-century. Most of those deaths will be attributable to natural processes like atmospheric chemistry and natural emissions, which are affected by rising temperatures. However, about 1,000 of those deaths each year would occur because of increased air conditioning powered by fossil fuel. "Climate change is here and we're going to need to adapt," says Abel. "But air conditioning and the way we use energy is going to provide a feedback that will exacerbate air pollution as temperatures continue to get warmer."The results of the new study, according to the Wisconsin team, underscore the need to change to more sustainable sources of energy such as wind and solar power, and to deploy more energy-efficient air conditioning equipment. "The answer is clean energy," says Abel. "That is something we can control that will help both climate change and future air pollution. If we change nothing, both are going to get worse."
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Weather
| 2,018 |
July 2, 2018
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https://www.sciencedaily.com/releases/2018/07/180702133850.htm
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Plants in Africa 'green up' ahead of rainy season
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A study led by the University of Southampton has shown the greening up of vegetation prior to the rainy season in Africa is more widespread than previously understood.
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Geographers from Southampton, working with scientists at Lancaster University, used remote sensing data (satellite imagery), sourced over a 16 year period (2000-2016), to examine when plants in the continent began and finished their green period of growth. This was compared with meteorological data showing the onset and conclusion of the rains.The researchers found that over 80 per cent of the natural vegetation commenced greening up before the beginning of the rainy season. This was most prominent in woodlands in the southern part of Africa, which saw greening as early as three months before the start of the rains. Only an estimated four per cent showed greening up after the rain began, and these were confined to the Sudano-Sahelian region above the equator.The study examined crops, grasslands and woodland. It showed that crops typically began their growing season after the wet weather, while woodlands mainly greened up a week or more before the arrival of the rains. Grasslands fell into two groups, those which greened at the same time as rain and those which greened much earlier.Jadu Dash, Professor in remote sensing at the University of Southampton comments: "These findings add further evidence to the 'pre-rain green up' phenomenon observed locally across vegetation types in Africa. The results contradict the widely held view that rainfall drives the onset and end of the vegetation growing season across Africa."Our study raises questions as to what environmental cues are initiating vegetation growth when rain isn't a factor. Climate change adds an extra dimension to this, making it even more important to understand how plants are responding to these cues."Several theories have been suggested for what drives plants to green up, other than rainfall. Among these are a form of climatic memory mechanism in plants, day length, temperature, air humidity and physical attributes of plants, such as their ability to tap reserves of nutrients or deep root systems which access underground water sources. Further research is needed to more fully understand these cues.The African continent contains the world's largest area of savanna and around 17 per cent of the world's tropical forests. Savannas alone account for 30 per cent of the primary production from global terrestrial vegetation, underlining the importance of African vegetation.Satellite remote sensing data used in the study was from NASA's MODIS sensor and the gridded rainfall dataset was from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS).
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Weather
| 2,018 |
July 2, 2018
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https://www.sciencedaily.com/releases/2018/07/180702094020.htm
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Artificial intelligence accurately predicts distribution of radioactive fallout
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When a nuclear power plant accident occurs and radioactive material is released, it is vital to evacuate people in the vicinity as quickly as possible. However, it can be difficult to immediately predict where the emitted radioactivity will settle, making it impossible to prevent the exposure of large numbers of people.
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A means of overcoming this difficulty has been presented in a new study reported in the journal This latest study was prompted by the limitations of existing atmospheric modeling tools in the aftermath of the accident at Fukushima; tools considered so unreliable that they were not used for planning immediately after the disaster. In this context, the team created a system based on a form of artificial intelligence called machine learning, which can use data on previous weather patterns to predict the route that radioactive emissions are likely to take."Our new tool was first trained using years of weather-related data to predict where radioactivity would be distributed if it were released from a particular point," lead author Takao Yoshikane says. "In subsequent testing, it could predict the direction of dispersion with at least 85% accuracy, with this rising to 95% in winter when there are more predictable weather patterns.""The fact that the accuracy of this approach did not decrease when predicting over 30 hours into the future is extremely important in disaster scenarios," Takao Yoshikane says. "This gives authorities time to arrange evacuation plans in the most badly affected areas, and to issue guidance to people in specific areas about avoiding eating fresh produce and taking potassium iodide, which can limit the absorption of ingested radioactive isotopes by the body."
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Weather
| 2,018 |
June 28, 2018
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https://www.sciencedaily.com/releases/2018/06/180628124412.htm
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Mars dust storm may lead to new weather discoveries
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Mars is experiencing an estimated 15.8-million-square-mile dust storm, roughly the size of North and South America. This storm may not be good news for the NASA solar-powered Opportunity rover, but one Penn State professor sees this as a chance to learn more about Martian weather.
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Steven Greybush, an assistant professor of meteorology and atmospheric science and Penn State Institute for CyberScience faculty co-hire, studies numerical weather prediction and the weather and climate of Mars."We are seeing the impact of this storm on Opportunity because it has caused it to shut down," Greybush said. "Opportunity is in the heart of the storm."Beginning on June 13, NASA was unable to contact Opportunity and it is believed that lack of sunlight has caused it to suspend operations to save energy. Opportunity, which originally launched on July 7, 2003, as a part of NASA's Mars Exploration Rover program, was designed to search for and characterize rocks and soils that hold clues to past water activity on Mars. These studies may give researchers key information about the possibility of life on the planet.Outside of the concern for the rover, Greybush said that the observations of these storms provide researchers with a wealth of data about weather, allowing them to more accurately model the atmospheric conditions along with getting closer to the possibility of being able to forecast the weather on Mars.Knowledge of Mars' weather will also help with planning future NASA missions, said Greybush."If we can learn more about the atmospheric conditions of Mars, we may be able to land in more interesting places, such as those with hills and craters rather than flat terrain," Greybush said.Greybush is working on a tool called Ensemble Mars Atmosphere Reanalysis System (EMARS). The system takes measurements received from orbiting spacecraft, such as temperature or dust, and combines the information with computer simulations using a process called data assimilation. EMARS creates a sequence of maps of winds, temperatures, pressures and dust at hourly intervals over six Martian years. A Mars year is 687 Earth days.With this information, Greybush can follow the evolution of dust storms and track how they grow from a local-scale dust storm to planetary scale.Along with tracking the storms, Greybush can use EMARS to compare the current dust storm to previous storms. This method yields important insights into the variability of Mars' weather patterns over time.Greybush hopes EMARS will assist other researchers in their study of the planet and help explore the predictability of traveling weather systems and dust storms. When speaking of traveling weather systems, Mars has seasons, pressure systems and weather fronts, much like Earth.Studying these dust storms and the weather on Mars may also assist in the study of Earth. Greybush said that traveling weather systems in the mid-latitude on Mars resemble those in the mid-latitudes on Earth.Hartzel Gillespie, a doctoral graduate student in meteorology working with Greybush, studies the traveling weather systems of Mars. Gillespie said that there are hypotheses that the winds of the weather systems may cause the formation of these dust storms."The current Martian dust storm will provide an interesting case study for that hypothesis," Gillespie said. "It would be quite interesting if we were able, in the future, to show that this dust storm was caused by a particular traveling weather system."Local and regional storms take place on Mars yearly, but estimates say that global storms occur once every three or four Martian years, which is six to eight Earth years.Global storms can occur from intense winds lifting the dust off of the ground -- sometimes up to 24 miles in altitude. As dust is carried higher into the atmosphere, it gets caught in faster winds and can be moved across the planet. It can take up to several weeks for the dust to settle."A lot of storms begin in the northern hemisphere and then fizzle out, so why did this northern storm make it past the equator and become so large?" Greybush asked. "The last global storm was in 2007. Each storm is unique, and this provides a new example for case studies."Mars is the planet that is most like Earth, as it shares similar characteristics and history, but the stark differences, such as the nature of its extreme weather, are what researchers are aiming to understand."People ask why we study Mars' weather and the simple answer is scientific curiosity," Greybush said. "We want to know what storms and weather are like on other planets. Are they similar or are they different? These dust storms give us data and insight into these processes."
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Weather
| 2,018 |
June 25, 2018
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https://www.sciencedaily.com/releases/2018/06/180625192640.htm
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New study explains Antarctica's coldest temperatures
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Tiny valleys near the top of Antarctica's ice sheet reach temperatures of nearly -100 degrees Celsius, according to a new study published this week in the AGU journal
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After sifting through data from several Earth-observing satellites, scientists announced in 2013 that they found surface temperatures of -93 degrees Celsius (-135 degrees Fahrenheit) in several spots on the East Antarctic Plateau, a high snowy plateau in central Antarctica that encompasses the South Pole. That preliminary study has been revised with new data showing that the coldest sites actually reach -98 degrees Celsius (-144 degrees Fahrenheit). The temperatures are observed during the southern polar night, mostly during July and August.When the researchers first announced they had found the coldest temperatures on Earth five years ago, they determined that persistent clear skies and light winds are required for temperatures to dip this low. But the new study adds a twist to the story: Not only are clear skies necessary, but the air must also be extremely dry, because water vapor blocks the loss of heat from the snow surface.The researchers observed the ultra-low temperatures in small dips or shallow hollows in the Antarctic Ice Sheet where cold, dense, descending air pools above the surface and can remain for several days. This allows the surface, and the air above it, to cool still further, until the clear, calm, and dry conditions break down and the air mixes with warmer air higher in the atmosphere."In this area, we see periods of incredibly dry air, and this allows the heat from the snow surface to radiate into space more easily," said Ted Scambos, a senior research scientist at the National Snow and Ice Data Center at the University of Colorado Boulder and the study's lead author.The record of -98 degrees Celsius is about as cold as it is possible to get at Earth's surface, according to the researchers. For the temperature to drop that low, clear skies and dry air need to persist for several days. Temperatures could drop a little lower if the conditions lasted for several weeks, but that's extremely unlikely to happen, Scambos said.The high elevation of the East Antarctic Plateau and its proximity to the South Pole give it the coldest climate of any region on Earth. The lowest air temperature ever measured by a weather station, -89 degrees Celsius (-128 degrees Fahrenheit), was recorded there at Russia's Vostok Station in July 1983.But weather stations can't measure temperatures everywhere. So in 2013, Scambos and his colleagues decided to analyze data from several Earth-observing satellites to see if they could find temperatures on the plateau even lower than those recorded at Vostok.In the new study, they analyzed satellite data collected during the Southern Hemisphere's winter between 2004 and 2016. They used data from the MODIS instrument aboard NASA's Terra and Aqua satellites as well as data from instruments on NOAA's Polar Operational Environmental Satellites.The researchers observed snow surface temperatures regularly dropping below -90 degrees Celsius (-130 degrees Fahrenheit) almost every winter in a broad region of the plateau, more than 3,500 meters (11,000 feet) above sea level. Within this broad region, they found dozens of sites had much colder temperatures. Nearly 100 locations reached surface temperatures of -98 degrees Celsius.The atmosphere in this region can sometimes have less than 0.2 mm total precipitable water above the surface. But even when it is that dry and cold, the air traps some of the heat and sends it back to the surface. This means that the cooling rates are very slow as the surface temperatures approach the record values. Conditions do not persist long enough -- it could take weeks -- for the temperatures to dip below the observed records. However, the temperature measured from satellites is the temperature of the snow surface, not the air above it. So the study also estimated the air temperatures by using nearby automatic weather stations and the satellite data.Interestingly, even though the coldest sites were spread out over hundreds of kilometers, the lowest temperatures were all nearly the same. That got them wondering: Is there a limit to how cold it can get on the plateau?Using the difference between the satellite measurements of the lowest surface snow temperatures at Vostok and three automated stations, and the air temperatures at the same place and time, the researchers inferred that the air temperatures at the very coldest sites (where no stations exist) are probably around -94 degrees Celsius, or about -137 degrees Fahrenheit.The research team has also developed a set of instruments designed to survive and operate at the very coldest places through the winter and measure both snow and air temperatures. They are planning to deploy the instruments in the next year or two, during the Antarctic summer when the temperatures are a comparatively mild -30 degrees Celsius (-22 degrees Fahrenheit).
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Weather
| 2,018 |
June 20, 2018
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https://www.sciencedaily.com/releases/2018/06/180620150203.htm
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The sounds of climate change
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Spring is coming earlier to parts of the Arctic, and so are some migratory birds. But researchers have yet to get a clear picture of how climate change is transforming tundra life. That's starting to change as automated tools for tracking birds and other animals in remote places come online, giving researchers an earful of clues about how wildlife is adapting to hotter temperatures and more erratic weather.
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In a new study in The researchers also turned the algorithm loose on their data with no training to see if it could pick out bird songs on its own and approximate an arrival date. In both cases, the computer's estimates closely matched what human observers had noted in the field. Their unsupervised machine learning method could potentially be extended to any dataset of animal vocalizations."Our methods could be retooled to detect the arrival of birds and other vocal animals in highly seasonal habitats," said the study's lead author, Ruth Oliver, a graduate student at Columbia. "This could allow us to track largescale changes in how animals are responding to climate change."Though relatively simple, these tools could speed up the analysis of acoustic datasets packed with biodiversity information valuable to conservationists and others, says Andrew Farnsworth, a researcher at the Cornell Lab of Ornithology who was not involved in the study."An archive of acoustic recordings tells you how biodiversity is changing over time," he said. "Understanding the dynamics of songbird arrival and breeding timing is the doorway to thinking about climate change and how temperature, weather and snowfall are affecting various species."Songbirds are notoriously difficult to track in the wild. Their migrations span thousands of miles and their bodies are too small to tag with GPS receivers. In a novel approach, Natalie Boelman, an ecologist at Columbia's Lamont-Doherty Earth Observatory, and her colleagues set out microphones in the foothills of Alaska's Brooks Range to eavesdrop on two particular species that fly in each spring to mate and raise their young: white-crowned sparrows and Lapland longspurs.Starting in 2010, the team recorded for five seasons at regular intervals from early May through July. The hoped to pin down when the birds were arriving and if the species mix would shift as plants favoring warmer temperatures expand their range. White-crowned sparrows prefer woody shrubs, and Lapland longspurs, open grasslands. With shrubs expected to dominate the area by 2050, sparrows could end up pushing out longspurs and other tundra-adapted birds.In the next phase of their research, the team hopes to develop the tool further to distinguish between sparrows and longspurs, among other species, to spot population-level trends.Species-specific identification is a complex problem that other researchers are trying to crack. At Cornell, Farnsworth and his colleagues are using deep learning tools in a project called BirdVox to classify recordings of migratory bird calls at night, when there's less competing noise to filter out. Wildlife Acoustics, a company near Boston, is building low-cost field recorders and developing software to track the comings and goings of birds, as well as frogs, bats, and whales, by the sounds they make."We want to know what species are present when humans are not," says Farnsworth. "We're trying to teach the machine to classify sound the way the human brain does."The longer the data set, the greater chance that a climate change signal will pop out. For Boelman, five years proved too short in a region known for big year-to-year swings in weather and temperature, which appear to be growing more extreme with climate change. In a recent study in Oecologia based on observational data, the team reported that both sparrows and longspurs appeared to time their arrival and breeding to local conditions; when a late spring delayed snowmelt by 10 days in 2013, the birds arrived 3 to 6 days later than usual, and hatched their young 4 to 10 days later."However, it's still unclear how songbirds will cope if spring comes even earlier or later than it did during our study period," said Boelman. "Species also time their migration and breeding with day length, which isn't shifting with climate change. Species whose migratory response is hard-wired to day length alone may not adapt as well to a changing environment."Other authors are Dan Ellis, Columbia Engineering; Helen Chmura, Jesse Krause, Jonathan Pereze and John Wingfield, University of California at Davis; Shannan Sweet, Cornell University; and Laura Gough, Towson University.The study was funded by the National Science Foundation's Office of Polar Programs and Graduate Research Fellow Programs; a $200,000 grant from Columbia's Data Science Institute; and NASA's Arctic-Boreal Vulnerability Experiment.
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June 20, 2018
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https://www.sciencedaily.com/releases/2018/06/180620094749.htm
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Whether wheat weathers heat waves
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A heat wave sweeps through a city and people swelter, running indoors to find air conditioning. But crops out in a field aren't so lucky. For them, there is no escape.
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Scientists in Australia are working to understand how heat waves impact wheat. They are mixing observational studies with techniques from computer science. This will allow them to create models to understand how wheat will respond in certain conditions.Heat can affect plants and the soil, water, air, and microbes around them in many different ways. Knowing how all of these factors affect crops could help farmers protect their plants against heat waves' effects."Heat waves can greatly reduce wheat in growing regions and modeling could aid in finding strategies to limit the impact of extreme weather and climate change," says James Nuttall. Nuttall works for Australia's Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources. "This can specifically come in handy during the sensitive periods of crop flowering and the grain filling phase."Wheat is an important crop with a worldwide production of 729 million tons in 2014. It is a major source of human nutrition. Nuttall says that maintaining stable production into the future includes finding ways to reduce the effects of heat stress to plants.Nuttall and his team performed three experiments. They tried to get a complete picture of the different characteristics of heat stress, such as timing, intensity, and duration. They tested how plants responded to a multi-day heat wave and if it affected plants more during their flowering or grain-filling phase. They also studied how water availability during the heat wave affected the wheat.Results showed that high temperatures five days before the wheat began to flower reduced the number of wheat grains on a plant. Also, a high-temperature event while the grain of wheat was growing reduced how big it got.They then put all the results together into a computer simulation model. This allowed them to predict how wheat beyond just the plants in their experiment could be impacted by a heat wave.Nuttall explains: "Crop modeling allows you to test responses for environment or treatment combinations, and also test how those interact with each other."He says a good example is in climate change studies where scientists are interested in plants' response to carbon dioxide levels, temperature, and rainfall. A crop model allows them to test combinations of these factors on growth and yield."These models allow us to make a prediction of crop growth and yield," he says. "In finding ways to combat heat waves, modeling provides a tool to see the effects of climate and weather changes on wheat production. It helps us predict how wheat will react so we can try to stop any negative effects beforehand."Nuttall says the next step in their research is to test their models using fields of wheat rather than a smaller sample of plants. They ultimately want to include their work in larger crop models to improve them."As a scientist, there is satisfaction in finding relationships between crop growth and stresses like heat waves," he says. "I also think the work is valuable because we can help crop models identify possible ways that allow us to keep producing the food our planet needs."This research was funded by the Australian Grains Research and Development Corporation and Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources.
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June 15, 2018
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https://www.sciencedaily.com/releases/2018/06/180615154505.htm
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New method makes weather forecasts right as rain
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Meteorologists have known for some time that rainfall forecasts have flaws, as failure to take into account factors such as evaporation can affect their accuracy. Now, researchers from the University of Missouri have developed a system that improves the precision of forecasts by accounting for evaporation in rainfall estimates, particularly for locations 30 miles or more from the nearest National Weather Service radar.
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"Right now, forecasts are generally not accounting for what happens to a raindrop after it is picked up by radar," said Neil Fox, associate professor of atmospheric science in the School of Natural Resources at MU. "Evaporation has a substantial impact on the amount of rainfall that actually reaches the ground. By measuring that impact, we can produce more accurate forecasts that give farmers, agriculture specialists and the public the information they need."Fox and doctoral student Quinn Pallardy used dual-polarization radar, which sends out two radar beams polarized horizontally and vertically, to differentiate between the sizes of raindrops. The size of a raindrop affects both its evaporation rate and its motion, with smaller raindrops evaporating more quickly but encountering less air resistance. By combining this information with a model that assessed the humidity of the atmosphere, the researchers were able to develop a tracing method that followed raindrops from the point when they were observed by the radar to when they hit the ground, precisely determining how much evaporation would occur for any given raindrop.Researchers found that this method significantly improved the accuracy of rainfall estimates, especially in locations at least 30 miles from the nearest National Weather Service radar. Radar beams rise higher into the atmosphere as they travel, and as a result, radar that does not account for evaporation becomes less accurate at greater distances because it observes raindrops that have not yet evaporated."Many of the areas that are further from the radar have a lot of agriculture," Fox said. "Farmers depend on rainfall estimates to help them manage their crops, so the more accurate we can make forecasts, the more those forecasts can benefit the people who rely on them."Fox said more accurate rainfall estimates also contribute to better weather forecasts in general, as rainfall can affect storm behavior, air quality and a variety of other weather factors.
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Weather
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June 13, 2018
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https://www.sciencedaily.com/releases/2018/06/180613101946.htm
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To forecast winter rainfall in the Southwest, look to New Zealand in the summer
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El Niño was long considered a reliable tool for predicting future precipitation in the southwestern United States, but its forecasting power has diminished in recent cycles, possibly due to global climate change. In a study published today in
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"The interhemispheric teleconnection that we have discovered promises earlier and more accurate prediction of winter precipitation in California and the southwestern U.S.," said study co-author Efi Foufoula-Georgiou, UCI Distinguished Professor of civil & environmental engineering. "Knowing how much rain to expect in the coming winter is crucial for the economy, water security and ecosystem management of the region."The researchers called the new teleconnection the New Zealand Index, because the sea surface temperature anomaly that triggers it begins in July and August in the southwestern Pacific Ocean, close to New Zealand. As the sea surface temperature in the region cools down or heats up, it causes a change in the southern Hadley cell, an atmospheric convection zone from the equator to about the 30th parallel south.This prompts a commensurate anomaly east of the Philippine Islands, which, in turn, results in a strengthening or weakening of the jet stream in the Northern Hemisphere, having a direct influence on the amount of rain that falls on California between November and March."With the New Zealand Index, we can predict from late summer the likelihood of above- or below-normal winter precipitation in the southwestern U.S., with a correlation in the order of 0.7 -- compared to the El Niño-Southern Oscillation technique, which has a correlation around 0.3 to 0.4," said lead author Antonios Mamalakis, a UCI graduate student in civil & environmental engineering. "Our research also shows an amplification of this newly discovered teleconnection over the past four decades."For the study, an interdisciplinary team of scientists analyzed sea surface temperature and atmospheric pressure in 1- and 2-degree cells around the globe from 1950 to 2015.Mamalakis said the unexpected result was the discovery of persistent sea surface temperature and atmospheric pressure patterns in the southwestern Pacific Ocean that exhibited a strong correlation with precipitation in Southern California, Nevada, Arizona and Utah.Climate researchers have traditionally relied on a few planet-spanning oceanic and atmospheric conditions to help them forecast future rainfall. Gradual changes in sea surface temperature in vast regions of the Atlantic and Pacific oceans, jet stream-influencing high-pressure ridges over the Gulf of Alaska, and the familiar El Niño-Southern Oscillation are all players in the precipitation prediction game.But in recent years, strongly positive El Niño conditions did not bring a lot of rain to California, as they had in the past, while the usually arid state received heavy precipitation in the winter of 2017, considered a neutral El Niño season."Predicting drought in the southwestern U.S. is a critical issue for food production and local economies," said Tom Torgersen, director of the National Science Foundation's Water Sustainability & Climate program, which funded the research. "The discovery of an interhemispheric bridge that affects the winter U.S. jet stream holds the promise of improved precipitation predictability and drought forecasts."
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Weather
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June 12, 2018
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https://www.sciencedaily.com/releases/2018/06/180612080026.htm
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Researchers investigate the correlation between wind and wave height in the Arctic Ocean
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An international research team led by Takuji Waseda, a professor of the University of Tokyo, Japan, has found an increase in high waves and winds in the ice-free waters of the Arctic Ocean, a potentially dangerous navigational tipping point for the "new and unusual" state of the waters.
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The research was conducted as part of an Arctic region research project, called the Arctic Challenge for Sustainability (ArCS). The project umbrellas eight themes, each focused on a different aspect of environmental improvement and sustainability in the Arctic. Through the encompassing research themes, the project has mobilized almost all of the polar scientists in Japan."Forecasting of waves and estimating the chance of sea spray icing on a ship is very important for safe navigation under the new and unusual state of the Arctic Ocean," said co-author Jun Inoue, an associate professor of polar science at the National Institute of Polar Research, a part of the Inter-University Research Institute Corporation Research Organization of Information and Systems (ROIS) in Tokyo, Japan.Inoue led the first theme of the ArCS project, which focused on studying the predictability of weather and sea-ice forecasts. The first theme of the project also looks into how users of the weather forecasts participate in providing related data to further improve such predictability.Their results were published in Researchers used the ERA-Interim reanalysis, a global atmospheric data collection system, to examine nearly four decades of emerging trends of increasingly extreme waves. They directly measured waves with buoys in the Arctic Sea in the summer of 2016 to validate the results predicted by the ERA-Interim reanalysis.They saw an increase in both winds and high ocean waves, as expected since a few million square kilometers of the sea's ice covering has melted in the past forty years.The larger the ice-free water area, the greater the probability of encountering a large wave, according to Waseda, which has potentially grave implications for the shippers navigating through the Northern Sea Route, as well as for the coastal populations."As the entire Arctic Ocean is expected to be ice free by 2050, the wave height is projected to increase correspondingly," Inoue wrote. Ice in the Arctic continues to melt, removing the windbreaks from the ice and allowing waves to grow."The gradual change in wave heights and frequency over the ice-free Arctic Ocean would influence not only... the business strategy of the [shippers] using the Northern Sea Route, but also on the local life near the coastal region," Inoue said.Coastal erosion would also increase with the height and frequency of waves, according to Waseda."We need a skillful surface wind speed forecast to predict wave heights," Inoue said. Such a tool would help people on ships, and the coasts better prepare for the turbulence and potential floodingInoue pointed to the Polar Prediction Project, of which he is a steering committee member, coordinated by the World Meteorological Organization. The project is running the Year of Polar Prediction, an aggregated forum for scientists to better forecast weather and climate conditions in the polar regions.
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Weather
| 2,018 |
June 11, 2018
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https://www.sciencedaily.com/releases/2018/06/180611152732.htm
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Warmer climate will dramatically increase the volatility of global corn crops
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Corn, or maize, is the most widely grown crop in the world. Used in food, cooking oil, industrialized foods, livestock feed and even automobile fuel, the crop is one that both rich and poor people rely upon.
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Research led by the University of Washington looks at what climate change will mean for global yields of this crop. The results show that warmer temperatures by the end of this century will reduce yields throughout the world, confirming previous research. But the study also shows dramatic increases in the variability of corn yields from one year to the next and the likelihood of simultaneous low yields across multiple high-producing regions, which could lead to price hikes and global shortages.The study was published the week of June 11 in the "Previous studies have often focused on just climate and plants, but here we look at climate, food and international markets," said lead author Michelle Tigchelaar, a UW postdoctoral researcher in atmospheric sciences. "We find that as the planet warms, it becomes more likely for different countries to simultaneously experience major crop losses, which has big implications for food prices and food security."In the wake of a recent UW study looking at the nutritional value of rice crops under climate change, this study addressed overall yields and price volatility of corn.While most rice is used domestically, corn is traded on international markets. Four countries -- U.S., Brazil, Argentina and the Ukraine -- account for 87 percent of the global corn exports (China mostly produces for domestic use). Today the probability that all four exporters would have a bad year together, with yields at least 10 percent below normal, is virtually zero.But results show that under 2 degrees Celsius warming, which is projected if we succeed in curbing greenhouse gas emissions, this risk increases to 7 percent. Under 4 degrees Celsius warming, which the world is on track to reach by the end of the century if current greenhouse gas emissions rates continue, there's an 86 percent chance that all four maize-exporting countries would simultaneously suffer a bad year.In other words, it suggests cases like the 2003 heat wave in Western Europe, which devastated crops there, will be more likely to coincide with bad years in other regions."Yield variability is important for determining food prices in international markets, which in turn has big implications for food security and the ability of poor consumers to buy food," Tigchelaar said.The study used global climate projections with maize growth models to confirm previous research showing that warmer temperatures will negatively affect corn crops."When people think about climate change and food, they often initially think about drought," Tigchelaar said, "but it's really extreme heat that's very detrimental for crops. Part of that is because plants grown at a higher temperature demand more water, but it's also that extreme heat itself negatively affects crucial stages in plant development, starting with the flowering stage and ending with the grain-filling stage."The results show that while warmer temperatures will severely decrease average maize yields in the southeastern U.S., Eastern Europe and sub-Saharan Africa, and will increase the variability in the U.S. and other exporting nations."Even with optimistic scenarios for reduced emissions of greenhouse gases, results show that the volatility in year-to-year maize production in the U.S. will double by the middle of this century, due to increasing average growing season temperature," said co-author David Battisti, a UW professor of atmospheric sciences. "The same will be true in the other major maize-exporting countries. Climate change will cause unprecedented volatility in the price of maize, domestically and internationally."The study did not include precipitation changes, since those are harder to predict, and projections show that changes will be small compared to the natural changes in rainfall from one year to the next. It also assumed that temperature swings will stay the same as today, though some models project temperatures will become more variable under climate change."We took a conservative approach and assumed the 'weather' will be the same, only acting on top of an overall warmer climate," Battisti said.The findings support efforts to pursue new agricultural technology to ensure food security for a growing global population. The authors write that their results "underscore the urgency of investments in breeding for heat tolerance."
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Weather
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June 5, 2018
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https://www.sciencedaily.com/releases/2018/06/180605172518.htm
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Injuries and loss of life boost religious faith after disasters
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Weather-related disasters can make people more religious but it depends on the toll they inflict, suggests new UBC research. If a disaster injures a significant number of people, it can strengthen religiosity among those who are already religious. But if a disaster inflicts mostly economic damage, the opposite effect applies.
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"It's generally assumed that disasters can intensify religious preferences or practices," said study author Oscar Zapata, a postdoctoral researcher in UBC's school of community and regional planning. "My analysis suggests that it depends on the frequency of disasters in that region and the specific impact of the disaster."Using data from an international survey conducted annually between 1995 and 2012, Zapata evaluated the responses of 12,333 Canadians to two questions: "Do you believe in God?" and "How often do you attend religious services?" He then compared their answers with records of natural disasters, like avalanches, wildfires or blizzards that occurred in Canada during the same time period.Eighty-two per cent of survey respondents said they believe in God, with the majority reporting that they are either Roman Catholic, Protestant or Christian Orthodox. Using statistical analysis, Zapata found that among the believers of God, religiosity increased following disasters that injured a significant number of people: for every one per cent increase in the number of injured due to a climate disaster, attendance at religious services increased by close to four per cent.Disasters with largely economic impact did not have the same effect. With every one per cent increase in the number of disaster events, belief in God among survey respondents dropped 26 per cent. And for every one per cent increase in the economic cost of a natural disaster, the probability of believing in God dropped two per cent."In other words, economic losses caused by natural disasters had much less impact on religious beliefs or practices compared to human losses," said Zapata. "This might be because people can recover from financial losses and they can rebuild homes as long as they have emergency funds or insurance. It's losing people they know that seems to drive people to religion to ease their pain or stress."He cautioned that the analysis is uniquely applicable to Canada, which has good infrastructure and strong insurance systems that lighten the financial burdens of disasters. "It would be interesting to compare the results with countries that experience more weather-related disasters or have weaker infrastructure and insurance markets."Future studies could also look at the specific channels through which climate-related disasters affect religious preferences, he added. "Do people become less religious as disasters and material losses increase in number because they have more scientific information that links these disasters to human-induced climate change? Or do climate disasters reaffirm religious people's beliefs that disasters are acts of God and that God will protect them? We need to do more research to understand these mechanisms."
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Weather
| 2,018 |
June 4, 2018
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https://www.sciencedaily.com/releases/2018/06/180604112451.htm
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Storm's coming: New technique for simulation of extreme weather events
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Predictions of how climate change may affect extreme weather systems, such as typhoons, are usually conducted using general circulation models (GCMs), which represent physical processes in the atmosphere or oceans.
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However, GCMs can be affected by uncertainties including imperfections in the model, such as the model's inability to fully describe the processes giving rise to the extreme weather, and uncertainties in the effects of future carbon emissions. To offset this, several different predictions should be made when modeling future climates, using an approach known as ensemble modeling. However, generating the wide range of data needed to begin an ensemble simulation can be complex and computationally demanding.Now, Associate Professor Kenji Taniguchi of Japan's Kanazawa University has developed a new simple method for generating the large amount of data required to initiate ensemble modeling. In his recent article, published in "The new method has several advantages over previously used approaches," Taniguchi says. "It has high computational stability, it can begin at any time and date, and it doesn't require any particular atmospheric structure; so, it can be used for simulating any type of weather event."The method was demonstrated to provide suitable initial conditions for the typhoon and global warming simulations.He notes the new method can provide the variety of conditions needed to explore the broad possibilities of meteorological phenomena. It could also allow assessment of changes in the probability of extreme events based on a wide spread of wind speed, pressure, and rainfall data.The new method, after some further refinement and development, could contribute to improving the practical use of future global warming experiments in estimation of the probability of risk factors for extreme events and related impact assessments."Only one GCM output was used in this study, and there were various other assumptions about the structure of the data," Taniguchi says. "In future work, simulations with multiple GCM outputs should be included to consider the uncertainties inherent in different GCMs and we should think about tailoring the data distribution to each individual case."Although developed originally for global warming studies, the possible applications of Taniguchi's new method are wide. It has potential for use in a broad range of problems requiring ensemble simulation, such as import assessment of variations in land cover change and sea surface temperature etc.
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Weather
| 2,018 |
May 31, 2018
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https://www.sciencedaily.com/releases/2018/05/180531131129.htm
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Cool weather can amplify attacks of tree-killing bark beetle
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As a warming climate invites the destructive southern pine beetle to expand its northern range, the cooler weather in this new habitat can potentially increase the lethality of the insect's assault on trees, according to a new study from Dartmouth College.
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The research demonstrates how climate change can create a destructive, one-two punch for forests that are already under attack, and another mechanism by which weather can influence the abundance of insect pests.In the study, the Dartmouth research team shows how the colder fall and winter temperatures encountered in northern latitudes influences the growth and development of immature southern pine beetles, leading to a more synchronized emergence of adults once the weather warms.The behavior detailed in the research raises the risk for pine forests because the emerging beetles kill trees by attacking in large numbers. The more beetles that are active at the same time, the better the chance they will overwhelm tree defenses and produce even more beetles for the next generation of attacks."Climate change is not only giving this destructive species new territory to prey on, it's creating a more lethal pest that can wreak havoc on forests," said Jeffrey Lombardo, who conducted the research as a PhD candidate at Dartmouth.While native to the southeastern United States, the southern pine beetle is thriving as the climate warms. The pest is an icon of range expansions that are being permitted by climate change. In 15 years, the insect has steadily increased its range from the southeastern U.S. into New Jersey, New York's Long Island, Connecticut, Massachusetts, and now as far north as upstate New York.In seeking to understand the mechanisms that reinforce the insect's success in response to climate change, the Dartmouth research focuses on how beetle development from larva to adult is impacted by varying weather patterns."This research gives us a more sophisticated understanding of how temperature differences impact a species that has moved beyond its traditional range," said Matthew Ayres, a professor of biology at Dartmouth, and a coauthor of the study. "We've come a long way from 2007 when we got our first hint of how the cooler winters were producing different seasonal patterns in beetle populations."To conduct the study, the team used a combination of approaches including in situ laboratory experiments, a theoretical development rate model, and field trapping of wild beetles in newly-occupied pine forests of New Jersey as well as in the beetle's historic habitat in the southeastern states.The research demonstrates that cooler fall and winter temperatures in their expanding northern range significantly increase the population of beetles at the end stage of larval development and also causes them to emerge en masse when the weather becomes warmer. This concentrated pooling of developing individuals -- a phenomenon known as phenological synchrony -- results in larger populations of mature beetles emerging at one time.Conversely, researchers found that when left in warmer temperatures, life stage convergence was absent; the beetles continued developing unabated and do not demonstrate a similar pooling of population in one stage of development.While not all species benefit from a large number of individuals in the same territory, the southern pine beetle relies on high population density to more effectively "bleed-out" pine trees. Coordinated mass-attacks on pine trees by beetles opens up additional resources, which can then support more beetles. This positive feedback can push the population into outbreak."The power of numbers from synchronously emerging beetles can spell disaster for pine trees," said Lombardo, who is joining the faculty of St. Mary's College in Maryland.The study, published in the journal According to the study, the physiological mechanism is relevant to any insects that have variable thermal responses among life stages, lack diapause and experience cool winters. The authors note that their work was inspired by studies of mountain pine beetles, a related species that occurs in western regions of North America.The study is a warning of how changing climate can bring new risks to forests, but is also an example of how science can help. The knowledge from this study is being built into the southern pine beetle prediction system, which is a tool for forest managers to anticipate seasons of high risk and ramp up detection and suppression efforts."Forests all over the world are being challenged by changes in the distribution and abundance of potential pests and this makes good science more important than ever," said Ayres.
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Weather
| 2,018 |
May 31, 2018
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https://www.sciencedaily.com/releases/2018/05/180531084415.htm
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Climate change increasing risks of lightning-ignited fires
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Fires ignited by lightning have and will likely continue to increase across the Mediterranean and temperate regions in the Southern Hemisphere under a warmer climate, according to a new study co-led by a Portland State University researcher.
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The study, published online in May in the journal El Niño-La Niña, known as ENSO, is the periodic warming and cooling periods of the equatorial eastern and central Pacific Ocean that affects the world's climate the most. The Indian Ocean Dipole, or IOD, is a similar ocean-atmospheric phenomenon characterized by changes in sea-surface temperatures between the eastern and western part of the Indian Ocean, while the Southern Annular Mode, or SAM, describes the north-south movement of the westerly wind belt that circles Antarctica and carries moisture to the southwest corners of all the Southern Hemisphere continents.Heat, oxygen, fuel and an ignition source combine to start wildfires, but where and how quickly a fire moves depends on the terrain, the types and condition of vegetation present and the weather, said Andrés Holz, the study's co-lead author and a geography professor in PSU's College of Liberal Arts and Sciences.The study found that of the three climate drivers, the SAM had the strongest impact on fire activity -- both lightning- and human-caused wildfires -- due to a combination of lower precipitation and higher temperatures, said Holz, who also serves as a faculty fellow at PSU's Institute for Sustainable Solutions.During the positive phase of SAM, the westerly winds contract toward Antarctica, leaving large areas in southern South America, South Africa and Australia rain-free. The recent positive trends in SAM are attributed to increasing greenhouse gas levels and the hole in the ozone layer."Now the winter is not as rainy and the summer is longer, drier and warmer," Holz said.Drier winters mean less moisture on the land, and warmer springs and summers are pulling the soil moisture into the air more quickly, allowing the soil and vegetation to dry out and ignite more readily, he said.The study found that the natural influence of the three climate modes (ENSO, IOD and SAM) on fire activity was stronger during the 21st century than during the last couple of decades of the 20th century as a result of anthropogenic warming. That trend is expected to continue.Climate change is amplifying climate-fire teleconnections, or the strength of long-distance relationships between weather patterns and fire During the onset of the 21st century, lightning-ignited fires were tightly coupled with upward trends in the SAM and rising temperatures across the Southern Hemisphere"We think that by having warmer oceans and warmer temperatures in general, we're going to see higher evaporation and heat transfer, and thus higher frequency of convective storms that in turn results in more lightning-ignited fires," Holz said. "And with a climate mode such as SAM stuck in its positive, fire-prone phase that seems to amplify climate change, it doesn't look good."But Holz cautions that it does not mean that there will be an increasing number of fires everywhere. Under warmer conditions, if precipitation stays constant, there will be increased fire activity in areas that already have plenty of fuel to burn but have historically been too humid or wet to burn. On the flip side, areas that are dry year-round will likely see a decline in fire activity with global warming unless there's a strong increase in rainfall."These trends are expected worldwide, not just in the Southern Hemisphere," Holz said.
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Weather
| 2,018 |
May 30, 2018
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https://www.sciencedaily.com/releases/2018/05/180530113118.htm
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Huddling for survival: monkeys with more social partners can winter better
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Wild monkeys which have more social partners form larger huddles in adverse weather and have a better chance of surviving winter, new research has found.
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Behavioural ecologists studied wild Barbary macaques in Morocco and found that monkeys that had more social partners -- the monkeys they groomed with -- would form larger huddles at night than those animals with fewer social partners, allowing them to save more energy for growth and reproduction.This method of keeping warm, called social thermoregulation, means that the macaques with more grooming partners would stay warmer, spend less energy on maintaining body temperature and be less exposed to environmental stress, increasing their probability of surviving winter.The study is the first to show that such social huddling may be a mechanism that connects social bonding to higher "fitness" -- the term used by scientists to measure of how well animals can cope with their local ecological conditions, usually measured by reproductive success and survival.Dr Bonaventura Majolo, a behavioural ecologist based in the School of Psychology at the University of Lincoln, carried out the study with Liz Campbell, Programme Director at the Moroccan Primate Conservation Foundation, who previously worked as a researcher studying Barbary macaque social behaviour at the University of Lincoln.He said: "In several species, research has found that the most sociable individuals within a group tend to experience greater survival, longevity, reproductive output, and offspring survival."We know from previous studies of a number of different species that forming social bonds positively affects survival and reproduction, but exactly how this happens was not clear."Barbary macaques were an ideal species to examine because of the varying social relationships they have with their group companions, and the extreme weather conditions they experience, such as cold and snowy winters, and hot and dry summers. We found that monkeys which were more sociable would huddle together during winter nights with their social partners, and that this led to the formation of larger huddles when it rained or the temperature dropped."Researchers examined the grooming behaviour and hierarchy of two wild groups of Barbary macaques during the day, before recording their sleeping locations, and how many monkeys were huddled together in preparation for the night.The air temperature and whether it had rained or snowed was also recorded, as well as the amount of time the primates spent grooming, their dominance rank, and whether the grooming pair was the same sex or opposite sex.Researchers found that monkeys that spent more time grooming together were more likely to huddle together, and that they would gather in larger groups when there was precipitation and low temperatures. The findings support previous research that increasing huddle sizes is a behavioural response to combat the adverse impact of cold climates.Liz Campbell, Programme Director at the Moroccan Primate Conservation Foundation, said: "Social thermoregulation through huddling, communal nesting or communal roosting, is a very widespread behaviour across a range of species, and this could therefore be a very widespread mechanism linking sociality with an evolutionary advantage."In the ecological conditions of our study where Barbary macaques experience severe winter energy deficits, the benefits provided by social thermoregulation can explain why more social monkeys are more likely to survive winter. In less extreme climates, more effective social thermoregulation could allow greater energetic investment in growth and reproduction, contributing to the greater longevity, reproductive output, and offspring survival experienced by more social individuals in other species.While previous research has investigated the link between sociality and fitness, it has often explored behaviours that may not apply generally across species, such as support provided by social partners in fights, protection from infanticide, or stress reduction from grooming."We were searching for a behavioural mechanism which could potentially apply across a diverse range of species to explain the fitness benefit of social bonds. We hope that our study will stimulate further research in this area, helping to understand the benefit of forming and maintaining social bonds, and thus the evolution of complex sociality."The findings have been published in the journal
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May 30, 2018
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https://www.sciencedaily.com/releases/2018/05/180530112935.htm
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Increasing heat is driving off clouds that dampen California wildfires
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Sunny California may be getting too sunny. Increasing summer temperatures brought on by a combination of intensifying urbanization and warming climate are driving off once common low-lying morning clouds in many southern coastal areas of the state, leading to increased risk of wildfires, says a new study.
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"Cloud cover is plummeting in southern coastal California," said Park Williams, a bioclimatologist at Columbia University's Lamont-Doherty Earth Observatory and lead author of the research. "And as clouds decrease, that increases the chance of bigger and more intense fires." Williams said the decrease is driven mainly by urban sprawl, which increases near-surface temperatures, but that overall warming climate is contributing, too. Increasing heat drives away clouds, which admits more sunlight, which heats the ground further, leading to dryer vegetation, and higher fire risk, said Williams. The study appears this week in the journal The research follows a 2015 study in which Williams first documented a decrease in cloud cover around the sprawling Los Angeles and San Diego areas. Urban pavement and infrastructure absorb more solar energy than does the countryside, and that heat gets radiated back out into the air -- a major part of the so-called heat-island effect, which makes cities generally hotter than the rural areas. At the same time, overall temperatures have been rising in California due to global warming, and this has boosted the effect. In the new study, Williams and his colleagues have found a 25 to 50 percent decrease in low-lying summer clouds since the 1970s in the greater Los Angeles area.Normally, stratus clouds form over coastal southern California during early morning within a thin layer of cool, moist ocean air sandwiched between the land and higher air masses that are too dry for cloud formation. The stratus zone's altitude varies with weather, but sits at roughly 1,000 to 3,000 feet. But heat causes clouds to dissipate, and decades of intense urban growth plus global warming have been gnawing away at the stratus layer's base, causing the layer to thin and clouds to burn off earlier in the day or disappear altogether. Cloud bases have risen 150 to 300 feet since the 1970s, says the study. "Clouds that used to burn off by noon or 1 o'clock are now gone by 10 or 11, if they form at all," said Williams.Williams and others have demonstrated a strong link between warming climate and increased wildfire in the western United States. But in southern California the link is more subtle, and clouds are a rarely studied part of the system.While few scientists have looked in detail at clouds, many California airports large and small have been collecting hourly cloud observations since the 1970s, not for research, but rather for navigational safety. Williams and his colleagues decided to tap this trove to develop a fine-grained picture of changing cloud cover over the region. They then compared it to a separate large database kept by the U.S. Wildland Fire Assessment System, whose researchers have regularly measured vegetation moisture in the hills outside Los Angeles for decades. By comparing the two sets of data, the team found that periods of less cloud cover during the summer correlated neatly with lower vegetation moisture, and thus more danger of fire.However, the study did not find that total area burned in summer has increased as a result of decreases in cloud shading. There are too many other factors at play, said Williams. These include yearly variations in rainfall, winds, locations where fires start, and perhaps most of all, decreases in burnable area as urban areas have expanded, and the increased effectiveness of fire-fighting. "Even though the danger has increased, people in these areas are very good at putting out fires, so the area burned hasn't gone up," he said. "But the dice are now loaded, and in areas where clouds have decreased, the fires should be getting more intense and harder to contain. At some point, we'll see if people can continue to keep up."The catastrophic California-wide fires that consumed over 550,000 acres in fall of 2017 were probably not strongly affected by the reductions in summer cloud cover, said Williams. Although he did find that vegetation is drier in fall seasons that follow summers with few clouds, the fall 2017 fires were driven mainly by extreme winds and a late onset of the fall rainy season. And ironically, part of this record wildfire wave resulted not from a recent record four-year drought driven in part by climate change, but rather from record rains that followed the drought, which produced a surfeit of flammable vegetation. Things will vary year to year, but Williams said he expects to see overall fire danger increase in California, as long as there is adequate vegetation to burn.The other authors of the study are Pierre Gentine of Columbia's Department of Earth and Environmental Engineering; Max Moritz and Dar Roberts of the University of California, Santa Barbara; and John Abatzoglou of the University of Idaho, Moscow.
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May 29, 2018
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https://www.sciencedaily.com/releases/2018/05/180529140945.htm
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The case of the relativistic particles solved with NASA missions
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Encircling Earth are two enormous rings -- called the Van Allen radiation belts -- of highly energized ions and electrons. Various processes can accelerate these particles to relativistic speeds, which endanger spacecraft unlucky enough to enter these giant bands of damaging radiation. Scientists had previously identified certain factors that might cause particles in the belts to become highly energized, but they had not known which cause dominates.
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Now, with new research from NASA's Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms -- THEMIS -- missions, published in Establishing the main cause of the radiation belt enhancements provides key information for models that forecast space weather -- and thus protect our technology in space."We've had studies in the past that look at individual events, so we knew local acceleration was going to be important for some of the events, but I think it was a surprise just how important local acceleration was," said Alex Boyd, lead author and researcher at New Mexico Consortium, Los Alamos, New Mexico. "The results finally address this main controversy we've been having about the radiation belts for a number of years."There are two main causes of particle energization in the Van Allen belts: radial diffusion and local acceleration. Radial diffusion, which often occurs during solar storms -- giant influxes of particles, energy and magnetic fields from the Sun, which can alter our space environment -- slowly and repeatedly nudges particles closer to Earth, where they gain energy from the magnetic fields they encounter. Many scientists had long thought this was the primary, or even only, cause of energization.However, early on in its mission, the Van Allen Probes showed that local acceleration, which is caused by particles interacting with waves of fluctuating electric and magnetic fields can also provide energy to the particles. The new research, which looked at nearly a hundred events over almost five years, shows that these wave-particle interactions are responsible for energizing particles around Earth 87 percent of the time.The scientists knew that local acceleration was at work because they observed mountains of energetic particles growing in one place, as the local acceleration mechanism predicts, rather than sliding in Earthwards as diffusion would.That's a large percentage for a process that wasn't perceived as a strong candidate even five years ago. "Radial diffusion is definitely important for the radiation belts, but wave-particle interactions are much more important than we realized," said Geoff Reeves, co-author at the New Mexico Consortium.
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May 28, 2018
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https://www.sciencedaily.com/releases/2018/05/180528151920.htm
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China floods to hit US economy: Climate effects through trade chains
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Intensifying river floods could lead to regional production losses worldwide caused by global warming. This might not only hamper local economies around the globe -- the effects might also propagate through the global network of trade and supply chains, a study now published in
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"Climate change will increase flood risks already in the next two decades -- and this is not only a problem for millions of people but also for economies worldwide," says Anders Levermann, project leader from the Potsdam Institute for Climate Impact Research (PIK) in Germany and the Columbia University in New York. Without further adaption measures, climate change will likely increase economic losses worldwide due to fluvial floods by more than 15 percent accumulating to a total of about 600 billion US dollar within the next 20 years. While the bulk of this is independent of climate change, the rise is not. "Not only local industries will be affected by these climate impacts," says Sven Willner, lead author of the study from PIK. "Through supply shortages, changes in demand and associated price signals, economic losses might be down-streamed along the global trade and supply network affecting other economies on a global scale -- we were surprised about the size of this rather worrying effect."The World Bank's lead economist with the Global Facility for Disaster Reduction and Recovery, Stéphane Hallegatte, who pioneered research in the area of indirect disaster effects but was not involved in the present study, comments: "This work combines two very innovative lines of work: global risk assessment for natural hazards and network theory to understand how localized shocks propagate in time and space. It contributes to scientific progress in multiple ways, but one of the most important policy messages for me is that the world is so interconnected that natural disasters are not local events anymore: everybody can be affected by a disaster occurring far away. It means that risk management is more than each country's responsibility: it has become a global public good."The study is based on projections of near-future river floods on a regional scale already determined by the greenhouse gas emissions that humans have so far emitted into our atmosphere -- impacts after 2035 depend on future additional emissions. The authors investigate the overall economic network response to river flood-related shocks, taking into account the inner dynamics of international trade. They do so with the specifically designed, new Acclimate-model, a dynamic economic computer simulation.Without major adaptation measures, China could suffer the biggest direct economic losses from river floods -- adding up to a total of more than 380 billion US dollar in economic losses over the next 20 years, including natural flood events not related to global warming. This corresponds to about 5 percent of China's annual economic output. 175 billion of the total losses in China will likely occur due to climate change. "This is a lot," says Willner, "and it is only the effect by river floods, not even taking into account other climate change impacts such as storms and heat waves."The European Union and the United States on the contrary might be affected predominantly by indirect losses passed down along the global trade and supply network. In the US, direct losses might be around 30 billion US Dollar, whereas indirect losses might be 170 billion US dollar in the next 20 years. "The EU will suffer less from indirect losses caused by climate-related flooding in China due to its even trade balance. They will suffer when flooded regions in China temporarily fail to deliver for instance parts that European companies need for their production, but on the other hand Europe will profit from filling climate-induced production gaps in China by exporting goods to Asia. This yields the European economy currently more climate-prepared for the future," says Willner. "In contrast, the US imports much more from China than it exports to this country. This leaves the US more susceptible to climate-related risks of economic losses passed down along the global supply and trade chain.""More intense global trade can help to mitigate losses from local extreme events by facilitating market adjustments," explains co-author Christian Otto from the Potsdam Institute and Columbia University. "When a supplier is impacted by a disaster hampering its production, international trade increases the chance that other suppliers can jump in and temporarily replace it. Interestingly, the global increase of climate-induced river floods could even cause net gains for some economies such as India, South East Asia, or Australia."The study's focus is not on damages to production facilities of businesses, but to what extent a regional economy stagnates due to flooding. "We adopted a rather optimistic view when it comes to the flexibility and promptness of shifting production towards non-affected suppliers after an extreme weather event," explains Christian Otto. "Hence our study rather underestimates than overestimates the production losses -- things could eventually turn out to be worse.""We find that the intensification of the mutual trade relation with China leaves the EU better prepared against production losses in Asia than the US. The prospect that the US will be worse off can be traced back to the fact that it is importing more products from China than it is exporting," says PIK's Anders Levermann. "Interestingly, such an unbalanced trade relation might be an economic risk for the US when it comes to climate-related economic losses. In the end, Trump's tariffs might impede climate-proofing the US economy."For resolving this risk and balancing out the negative trade relation, there are generally two options: either isolation or more trade. "By introducing a tariff plan against China, Trump currently goes for isolation," says Levermann. "But Trump's tariff sanctions are likely to leave US economy even more vulnerable to climate change. As our study suggests, under climate change, the more reasonable strategy is a well-balanced economic connectivity, because it allows to compensate economic damages from unexpected weather events -- of which we expect more in the future."
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May 24, 2018
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https://www.sciencedaily.com/releases/2018/05/180524141647.htm
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New theory finds 'traffic jams' in jet stream cause abnormal weather patterns
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The sky sometimes has its limits, according to new research from two University of Chicago atmospheric scientists.
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A study published May 24 in The deadly 2003 European heat wave, California's 2014 drought and the swing of Superstorm Sandy in 2012 that surprised forecasters -- all of these were caused by a weather phenomenon known as "blocking," in which the jet stream meanders, stopping weather systems from moving eastward. Scientists have known about it for decades, almost as long as they've known about the jet stream -- first discovered by pioneering University of Chicago meteorologist Carl-Gustaf Rossby, in fact -- but no one had a good explanation for why it happens."Blocking is notoriously difficult to forecast, in large part because there was no compelling theory about when it forms and why," said study coauthor Noboru Nakamura, a professor in the Department of the Geophysical Sciences.Nakamura and then-graduate student Clare S.Y. Huang were studying the jet stream, trying to determine a clear set of measurements for blocking in order to better analyze the phenomenon. One of their new metrics was a term that measured the jet stream's meander. Looking over the math, Nakamura realized that the equation was nearly identical to one devised decades ago by transportation engineers trying to describe traffic jams."It turns out the jet stream has a capacity for 'weather traffic,' just as highway has traffic capacity, and when it is exceeded, blocking manifests as congestion," said Huang.Much like car traffic, movement slows when multiple highways converge and the speed of the jet stream is reduced due to topography such as mountains or coasts.The result is a simple theory that not only reproduces blocking, but predicts it, said Nakamura, who called making the cross-disciplinary connection "one of the most unexpected, but enlightening moments in my research career -- truly a gift from God."The explanation may not immediately improve short-term weather forecasting, the researchers said, but it will certainly help predict long-term patterns, including which areas may see more drought or floods.Their initial results suggest that while climate change probably increases blocking by running the jet stream closer to its capacity, there will be regional differences: for example, the Pacific Ocean may actually see a decrease in blocking over the decades."It's very difficult to forecast anything until you understand why it's happening, so this mechanistic model should be extremely helpful," Nakamura said.And the model, unlike most modern climate science, is computationally simple: "This equation captures the essence with a much less complicated system," Huang said.
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May 24, 2018
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https://www.sciencedaily.com/releases/2018/05/180524141542.htm
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Some desert creatures may be able to cope with climate change better than expected
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The world of reptiles may well include creatures that are more spectacular than the
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These geckos are small grey- or brown-skinned lizards that grow to around five centimetres and spend their lives in the deserts of Australia. The hollowed out trunks of eucalyptus trees are their preferred hiding places. After spending the night hunting insects, this is where they seek refuge from the heat in a climate where temperatures can often climb to more than 40 degrees Celsius. And it is in exactly these deserts where climate scientists expect to see even more extreme conditions in the future. They are forecasted to become even hotter and drier, worldwide. So how will the unique animals and plants that live in these ecosystems cope with these new challenges? This was the question the researchers set out to investigate, using this little gecko as a representative of other nocturnal desert inhabitants.Prof. Klaus Henle, head of the Department of Conservation Biology at the Helmholtz Centre for Environmental Research, began collecting data about Gehyra variegata as far back as the 1980s. Working in the Kinchega National Park in Eastern Australia, he and his colleagues have been catching, measuring, photographing, tagging and then releasing reptiles for more than 30 years.The researchers at the Helmholtz Centre for Environmental Research then collated this information with weather conditions in the National Park, and also with global climate phenomena. Their findings are surprising, to say the least. As biologist Annegret Grimm-Seyfarth said, "We expected the higher temperatures and greater dryness to have a negative effect both on the individual geckos and on their populations." After all, even lizards need a certain amount of moisture to ensure that their eggs develop properly, and to enable them to moult when they need to. If they dry out completely, they will die. And the same is also true if excessive temperatures cause them to overheat. "But our investigations revealed that our geckos grow and survive particularly well in the very hottest years. In fact, they are generally in better condition, and their populations grow rather than fall." But what could be the reason? To discover this, Grimm-Seyfarth carefully observed the lizards' behaviour and measured their body temperature.At night, she used an infrared thermometer, which can measure temperature at a distance, to locate the creatures while they were hunting. And then, to find where the geckos were hiding during the day, the scientists used tiny passive transmitters, similar to those used as ID chips for dogs. These chips are usually implanted under the skin. But when the tiny reptile is only five centimetres long, this isn't really feasible. So, the scientists created miniature backpacks for the geckos to wear, which keep the chips close to their skin. The researchers then use a radio antenna to locate the chips. The chips not only reveal where each lizard is, but also transmit its body temperature. Despite the tremendous daytime heat in the desert, the scientists discovered that the geckos don't search out particularly cool places to hide. They prefer their refuges to have a temperature between 30 and 35 degrees Celsius. As Grimm-Seyfarth said, "The creatures need these high temperatures so that they can digest their food properly." Consequently, they also crawl around in branches that are particularly exposed to the sun. To her astonishment, Grimm-Seyfarth also found that, in cooler years, the geckos left the safety of their tree and deliberately sat out in the sun to bask in its heat. But searching for enough warmth also takes energy. And, if the search is unsuccessful, the gecko can't digest its food properly. This might be the reason that cooler years had a negative effect on the geckos.However, even having the perfect temperature range isn't any good if it's also too dry. This doesn't just cause physical problems for these creatures. In particularly dry periods, there are also fewer insects for them to eat. As expected, geckos experience really hard times during periods of drought. But it's not just local precipitation levels that are the decisive factor. Every few years, the La Niña weather phenomenon brings torrential rainfall to the east coast of Australia. Months later, the rivers bring the resulting flood waters to the desert, increasing humidity levels and creating an abundance of insects. As Grimm-Seyfarth said, "These lizards are affected by local conditions and global climate phenomena alike. We need to look beyond the horizon of a particular area if we want to make an accurate prediction about the future of its inhabitants.Until now, all the evidence indicated that the geckos would face problems caused by drought rather than by heat. But now, we have discovered that they can also compensate for this, to a certain extent. The study shows that, although individual creatures become thinner in years of drought, their population levels remain constant. This is because they scale back their growth and reproduction rates in hard times," explained Grimm-Seyfarth. They can then concentrate all their efforts on surviving into the next year. Thanks to their exceptional longevity (up to 28 years in some cases), these creatures can afford to lose a few reproductive cycles without any particular problem. And when conditions improve again, they can make up for lost time.Therefore, even if climate change causes deterioration in living conditions for these geckos, they're hardly likely to die out immediately. And, according these evaluations by the scientists at the Helmholtz Centre for Environmental Research, these findings could also apply to other long-lived desert dwellers. However, this is in no way a simple carte blanche for letting climate change just happen. "If there are several very dry years in succession, the creatures will no longer be able to cope," said Grimm-Seyfarth. At some point, even the hardiest survival specialists will be overwhelmed.
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May 24, 2018
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https://www.sciencedaily.com/releases/2018/05/180524104053.htm
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Giant clams tell the story of past typhoons
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A highly precise method to determine past typhoon occurrences from giant clam shells has been developed, with the hope of using this method to predict future cyclone activity.
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A team of researchers led by Tsuyoshi Watanabe of Hokkaido University has discovered that giant clams record short-term environmental changes, such as those caused by typhoons, in their shells. Analyzing the shell's microstructure and chemical composition could reveal data about typhoons that occurred before written records were available.With the global warming of the climate, scientists are concerned that major tropical cyclones such as typhoons and hurricanes will increase. To better predict the frequency of these weather patterns, understanding typhoons in the past warmer periods of Earth's history is particularly important.The giant clam With these methods, the team found the growth pattern and chemical compositions in the shells were altered by short-term environmental changes in the area. Cooler ocean temperatures and other environmental stresses brought on by typhoons disrupted shell growth and increased the barium/calcium ratio as well as the stable isotope ratio."Since microstructural and geochemical features are well preserved in giant clam fossils, it may now be possible to reconstruct the timing and occurrence of past typhoons to a level of accuracy that was previously impossible," says Tsuyoshi Watanabe of Hokkaido University.
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May 23, 2018
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https://www.sciencedaily.com/releases/2018/05/180523091251.htm
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Floridians could far far more frequent, intense Heatwaves
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By the late 21st century, if atmospheric greenhouse gas concentrations reach worst-case projections, Floridians could experience summer heatwaves three times more frequently, and each heatwave could last six times longer than at present, according to Meteorology Professor Shawn M. Milrad of Embry-Riddle Aeronautical University.
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"More extreme heatwaves in Florida would have profound impacts on human health as well as the state's economy," Milrad said. "Heatwaves are a silent killer, claiming hundreds of thousands of lives each year, yet we tend to focus more on the risks associated with sudden, dramatic events such as hurricanes." In May 2015, for example, temperatures as high as 117 degrees Fahrenheit swept across India, causing widespread power outstands and killing at least 2,500 people.For the time period 2070 to 2099, if atmospheric concentrations of carbon dioxide -- a key greenhouse gas -- reach two to three times the current level of 410 parts per million, heatwaves would also get hotter, rising roughly 7 to 10 degrees Fahrenheit (4 to 6 degrees Celsius).This finding was reported by Milrad and others in their peer-reviewed article, "Floridian heatwaves and extreme precipitation: future climate projections," published in the journal Greenhouse gases -- primarily from fossil fuel burning and deforestation -- trap heat near the Earth's surface, he noted.Milrad and colleagues looked at temperatures and precipitation events today versus under the highest greenhouse gas-concentration scenario set forth by the Intergovernmental Panel on Climate Change (IPCC), which has identified four possible trajectories from mid-century through 2100.Specifically, researchers used surface observations and high-resolution Weather Research and Forecast model simulations to compare current surface air temperatures and rainfall conditions with what would happen near the end of the century under the) IPCC's gloomiest climate projection. The team included Milrad, Embry-Riddle graduate Ajay Raghavendra (now at the University at Albany); undergraduate meteorology major Shealynn R. Cloutier-Bisbee; and Aiguo Dai at the University at Albany and the National Center for Atmospheric Research.The team assessed heatwave risks for Florida, including the following six cities: Daytona Beach, Jacksonville, Miami, Orlando, Tallahassee and Tampa."All of the cities we assessed generally showed the same trends," Milrad said. "The one city that stood out a bit was Tampa, which showed a very large increase in daily mean and nighttime minimum temperatures, in our projections."Under a very high-level greenhouse gas scenario, precipitation would also increase following heatwaves, though this impact might vary from region to region, researchers found. "Florida's precipitation, by its convective nature, is quite scattered," Milrad said. "So it's difficult to pinpoint which regions might get hit the hardest with precipitation in the future, but a much warmer atmosphere would hold more moisture, so any given precipitation event would likely bring heavier amounts of precipitation."Deadly Nighttime ImpactsBecause temperatures are increasing faster at night, Milrad said, heatwaves are already becoming more frequent and intense at night, versus during the day. Soaring nighttime temperatures could be particularly troublesome for Floridians in large cities such as Miami, Tampa and Orlando, where the urban heat island phenomenon could amplify heatwaves, given that paved surfaces and concrete trap heat."Heatwaves can actually take a greater toll on human health at night because they affect how we sleep," Milrad said.Raghavendra, lead author of the Climate Dynamics paper and now a Ph.D. student at the University at Albany, noted that hotter, more frequent heatwaves could disrupt Florida's economy, too. "There would also be tremendous pressure on the energy sector, in particular, to generate enough power necessary to run air-conditioners and keep people cool."Milrad added: "Heatwaves in Florida aren't normally something people think about because it's always hot in Florida, yet many people still don't have access to good air-conditioning, and that makes them especially vulnerable to increasing temperatures."
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May 17, 2018
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https://www.sciencedaily.com/releases/2018/05/180517102356.htm
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Monitoring of tropical trees in face of climate change
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Experts have challenged the principle that tropical ecosystems are aseasonal -- after discovering regular cycles in fruiting, flowering and leafing in such climates.
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Researchers from the University of Stirling made the unexpected observations after studying 30 years of data from 851 tropical trees in the Lopé National Park in Gabon, Central Africa.The team -- led by Stirling PhD researcher Emma Bush -- also uncovered the reasons behind inaccuracies in previous monitoring of tropical tree behaviour and made recommendations to enhance future approaches. This will improve monitoring and, in turn, the data that is available for organisations that manage tropical ecosystems and their products, which support livelihoods and the survival of wildlife.The research is published in a special section of the Ms Bush's study -- entitled Towards effective monitoring of tropical phenology: maximising returns and reducing uncertainty in long-term studies -- assessed the Lopé dataset, which is the longest, unbroken record of Central African rainforest behaviour in the world. The data, which includes unique data on phenology patterns, local weather, forest productivity, and animal populations, allows scientists to analyse climate change effects on the landscape.The academics identified regular cycles in 36 per cent of samples and found flowers are much more likely to occur on a regular, annual cycle than fruits and leaves. The relative unpredictability of fruiting events underscores how complex these tropical ecosystems are, with a lot of variation at individual tree and species level.They also analysed the processes used to monitor cycles to understand why regular cycling activity is observed in some species and not others."We found that, on average, new leaves are easier to spot in the tropical forest canopy than flowers and that, both the visibility of the event and how long it lasts, are really important influences on whether we can detect this behaviour," explained Ms Bush."We also found evidence that supports the approach of long-term monitoring to understand these highly complex tropical plant communities. Significantly, we found that the chance of detecting regular cycles doubled when monitoring lasted 20 years, compared to 10."Dr Abernethy, Professor Nils Bunnefeld and Kathryn Jeffery, Research Fellow, all from Stirling, also collaborated on the research.Dr Abernethy, Ms Bush and Ms Jeffery are also co-authors on a related paper, entitled Annual cycles dominate reproductive phenology of African tropical trees, also published in the special section, which focuses on plant behaviour -- such as fruiting, flowering and leaf fall -- in tropical ecosystems.Dr Abernethy said: "The special section is about cycles of productivity and natural cycles in tropical ecosystems -- and how these are changing with the age of trees; seasonal changes related to climate change; and unpredictable climatic effects."It's also about how poorly these patterns are understood, even though they are critical for feedback to local weather, for humans using forests -- such as for timber or for food -- and for animals relying on plants for fruit as food."The research underlines how long it takes to understand the behaviour of such diverse systems as tropical forests, or such long-lived organisms as rainforest trees, and how essential it is that this research sector expands."The University of Stirling oversees the science programme in Lopé National Park for the Gabon National Parks Agency, which collaborated on the Bush et al's paper. The International Medical Research Centre in Franceville, Gabon, were also involved in the work.
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May 17, 2018
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https://www.sciencedaily.com/releases/2018/05/180517081817.htm
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Critically endangered South American forests were planted by ancient peoples
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Critically endangered South American forests thought to be the result of climate change were actually spread by ancient communities, archaeologists have found.
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Huge swathes of land in Chile, Brazil and Argentina are covered with millions of Araucaria, or monkey puzzle trees, thanks to people planting or cultivating them more than a thousand years ago, a new study shows. Recent logging means the landscape is now one of the world's most at-risk environments.It had been thought the forests expanded due to wetter and warmer weather. But the research shows the rapidly expanding pre-Columbian population of South America, Southern Jê communities, were really responsible.New excavations and soil analysis shows the forests, still hugely culturally and economically important to people living in South America, expanded between 1,410 and 900 years ago because of population growth and cultural changes.Dr Mark Robinson, from the University of Exeter, who led the British Academy and AHRC-FAPESP-funded research, said: "Our research shows these landscapes were human-made. Communities settled on grassland, and then -- perhaps because they modified the soil, protected seedlings or even planted trees -- established these forests in places where geographically they shouldn't have flourished."The forests date back to the period when dinosaurs roamed. The iconic monkey puzzle tree, or Parana pine, has grown in the region for thousands of years. Its nuts were one of the most important food sources for ancient communities, attracted game for hunting when nuts were ripe. They were also a valuable source of timber, fuel and resin, and became an integral part of southern Jê cosmology. Communities still call themselves "people of the Araucaria," and hold festivals to celebrate the forests.Of the 19 species of Araucaria tree, five are classified as endangered and two, including the Brazilian Araucaria angustifolia, are critically endangered. Reports from the late 1800s describe trees with diameters of over 2 m, reaching 42 m in height. Modern trees are only around 17.7 m tall.The archaeological analysis began because the experts, from the University of Exeter, University of Reading, University of São Paulo, University of New Mexico, Universidade Federal de Pelotas and Universidade do Sul de Santa Catarina, noticed that in areas of low human activity forests are limited to south-facing slopes, whereas in areas of extensive archaeology, forests cover the entire landscape. They were able to analyse soil isotopes reflecting vegetation and archaeological evidence from Campo Belo do Sul, Santa Catarina State, Brazil, to test whether this pattern was directly related to past human activity.The study shows the forests first expanded around 4,480 to 3,200 years ago, most likely near streams, and this may have been caused by a wetter climate. But a more rapid and extensive expansion across the whole region later happened between 1,410 and 900 years ago, when forests expanded into highland areas. The weather during this time was dry and less humid. This expansion of the forests coincides with population growth and increasingly complex and hierarchical societies in South America.The expansion in forests reached a peak around 800 years ago. The number of people in South America declined 400 years ago when European settlers arrived in the area. The population did not begin to recover until the 19 century, when loggers began exploiting the Araucaria forests for timber.Professor José Iriarte, from the University of Exeter, another member of the research team, said: "This study shows the Araucaria forests were expanded beyond their natural boundaries, they were used sustainably for hundreds of years, and conservation strategies must reflect this so they balance protection, heritage and economic development."Uncoupling human and climate drivers of late Holocene vegetation change in southern Brazil is published in the journal
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May 16, 2018
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https://www.sciencedaily.com/releases/2018/05/180516221443.htm
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European wind energy generation potential in a 1.5 degree C warmer world
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The UK and large parts of northern Europe could become windier if global temperatures reach 1.5 degrees C above pre-industrial levels, according to a new study.
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This has implications for wind energy generation among other things. The results suggest that wind could be a more important source of energy generation than previously thought, with stronger winds across the UK. The research team concludes there could be a 10% increase in UK onshore wind energy generation, which would be sufficient to power the equivalent of an extra 700,000 homes every year based on current installed capacity. The results are relevant for decisions about future investment in onshore wind farms.To evaluate potential changes in European wind power generation in a 1.5 degrees C warmer world, researchers from British Antarctic Survey, the University of Oxford and the University of Bristol combined data from 282 onshore wind turbines collected over 11 years with climate model data from the HAPPI project.This study did not consider offshore wind energy generation potential.Across northern Europe, the results suggest that large areas of Germany, Poland and Lithuania could become more viable for wind power in future. But the biggest increases in wind could be seen in the UK -- along with marked seasonal shifts in wind.Lead author, climate modeller Dr Scott Hosking at British Antarctic Survey, says:"In future, nine months of the year could see UK wind turbines generating electricity at levels currently only seen in winter. Future summers could see the largest increase in wind generation. Therefore, wind could provide a greater proportion of the UK's energy mix than has been previously assumed."Wind power is central to a low carbon economy. In Europe, wind energy currently accounts for 18% of total generating capacity and the European Commission's 2030 energy strategy set a renewables target of at least 27%.However, wind is also a highly variable energy source. While weather forecasts can help even out short-term differences in supply and demand, governments and industry need more information on longer-term changes in wind.Signatories of the Paris Agreement have committed to keep global average temperatures to well below 2 degrees C increase from pre-industrial times, with an ambition to limit the increase to 1.5 degrees C.
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May 16, 2018
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https://www.sciencedaily.com/releases/2018/05/180516101410.htm
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Small birds almost overheat while feeding their young
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For decades, researchers have thought that access to food determined the brood size of birds. Now, biologists at Lund University in Sweden have discovered a completely new explanation: the body temperature of small birds can increase by more than 4°C to exceed 45°C when they are feeding their young. Larger broods would require more work, resulting in even higher body temperatures -- something the birds would probably not survive.
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"A body temperature of over 45°C must be close to fatal even for small birds," says Jan-Åke Nilsson, professor at Lund University.Small birds, passerines, normally have a body temperature of around 41°C. Jan-Åke Nilsson and his colleague Andreas Nord studied marsh tits, discovering that their body temperature increased considerably as they worked hard, for example when feeding their young.Flying back and forth to the nest means they do not get the opportunity to get rid of excess heat, resulting in a higher body temperature.In addition, the study shows that the tits' body temperature follows the surrounding temperature. When the weather is warm, the birds' body temperature increases."If the climate becomes warmer, it could make small birds more vulnerable. Warmer springs would force them to produce and raise fewer offspring because they cannot feed them as often without risking death," says Jan-Åke Nilsson.The researchers conducted the study by manipulating the brood size of the tits, making the broods larger or smaller. This enabled them to increase the variation in how hard the birds were forced to work. When the parents returned to the nesting box, the researchers measured their body temperature."It is interesting to observe that the marsh tits' physiological systems worked even with fluctuations in temperature of the magnitude we have shown. Imagine how humans would feel if our body temperature increased by 4°C," concludes Jan-Åke Nilsson.
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May 15, 2018
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https://www.sciencedaily.com/releases/2018/05/180515131538.htm
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Traditional knowledge sheds light on changing East Greenland climate and polar bear hunt
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Inuit polar bear subsistence hunters from two East Greenland regions, Tasiilaq and Ittoqqortoormiit, report changes to their hunting patterns as well as polar bear distribution and behavior due to decreasing sea ice and the introduction of hunting quotas in 2006. The hunters have observed large climate changes in their hunting areas -- including warmer weather, less sea ice and disappearing glaciers -- which the majority say have affected the polar bear hunt. More hunters are now using boats than dog sledges due to loss of sea ice. The hunters also note that more polar bears are coming into their communities looking for food, and that the bears are eating more seal parts than previously. Published in
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Inuit hunters have a strong understanding of the Arctic environment and can share information passed down from older generations as well as from their personal experiences. This is very valuable to management and conservation efforts.Although traditional ecological knowledge about polar bears has been collected extensively in West Greenland, no comprehensive interview studies on polar bears have been carried out in East Greenland for close to two decades. Thus, current perspectives of polar bear hunters in this area are not well documented."Our research was motivated by the importance of obtaining local perspectives from subsistence hunters in East Greenland about the subpopulation of polar bears," says author Kristin L. Laidre, principal scientist at the Polar Science Center, University of Washington, USA. "There had not been an interview study for several decades so a new interview survey was important to conduct, especially before starting an assessment of the subpopulation."In interviews conducted by the Greenland Institute of Natural Resources, researchers gathered Inuit perspectives on polar bear subsistence quotas and hunting strategies from 25 full-time polar bear hunters in Tasiilaq and Ittoqqortoormiit. The aim was to gain an understanding of how climate change is affecting the polar bear subsistence hunt, and to document observed changes in polar bear distribution, abundance and biology over the last two decades.All interviewed hunters reported that they had observed changes to sea ice conditions. They noted, for example, that there is less ice, that the sea ice does not form or that it forms later than before, and that it is now more dangerous. Fifteen Tasiilaq hunters also said that the glaciers are disappearing very quickly. All Tasiilaq hunters noted changes in the weather, marked by worsened weather, warmer temperatures, more storms and more wind. Similarly, 89% of Ittoqqortoomiit hunters reported changing weather with warmer temperatures and more humidity.Seventy-three percent of Tasiilaq hunters and 88% of Ittoqqortoormiit hunters said that climate changes had affected the polar bear hunt. Furthermore, 100% of interviewed Tasiilaq hunters and 80% of Ittoqqortoomiit hunters reported that they hunt more with boats than with dog sledges compared to 10-15 years ago, due to decreasing sea-ice mass and larger extents of open water. One hunter said that he had gotten rid of his sledge, since he had no use for it anymore.Neither Ittoqqortoormiit nor Tasiilaq hunters reported major changes in the bears' body condition, which is consistent with previous reports from indigenous people in other areas. However, Tasiilaq hunters noted that polar bears are consuming more seal parts than before, such as bones and skin.In addition, 81% of Tasiilaq hunters and 78% of Ittoqqortoormiit hunters noted that more polar bears are coming into towns and settlements compared to 10-15 years ago. Moreover, hunters from both regions noted that more bears were caught near settlements than previously. While some hunters explained this as a result of the hunting quotas increasing the abundance of polar bears, others mentioned decreasing sea ice as a possible reason. Two hunters suggested that polar bears are coming closer to the towns because they have less to eat and are searching for food.The researchers report that 40% of Tasiilaq respondents had caught between 10-19 polar bears in their lifetime, while 67% of Ittoqqortoormiit respondents had lifetime catches of more than 20 bears. The general consensus in Tasiilaq is that the quotas are necessary, whereas hunters in Ittoqqortoomiit do not view the quotas as necessary. Hunters in both areas would like to see a small portion of the quota used for trophy hunting, which is currently illegal in Greenland.The researchers point out that understanding the impact of management decisions and the decreasing sea ice is essential for polar bear conservation and management, as well as for the human communities that rely on hunting polar bears. Thus, this research provides an important baseline for monitoring future changes and for managing the polar bear population."This information can be used to directly guide scientific lines of inquiry, improve management decisions, and overall ensure that traditional ecological knowledge is considered in the conservation and management of polar bears," concludes Laidre.
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May 15, 2018
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https://www.sciencedaily.com/releases/2018/05/180515113555.htm
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New approach to global-warming projections could make regional estimates more precise
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A new method for projecting how the temperature will respond to human impacts supports the outlook for substantial global warming throughout this century -- but also indicates that, in many regions, warming patterns are likely to vary significantly from those estimated by widely used computer models.
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The new method, outlined by McGill University researchers in "By establishing a historical relationship, the new method effectively models the collective atmospheric response to the huge numbers of interacting forces and structures, ranging from clouds to weather systems to ocean currents," says Shaun Lovejoy, a McGill physics professor and senior author of the study."Our approach vindicates the conclusion of the Intergovernmental Panel on Climate Change (IPCC) that drastic reductions in greenhouse gas emissions are needed in order to avoid catastrophic warming," he adds. "But it also brings some important nuances, and underscores a need to develop historical methods for regional climate projections in order to evaluate climate-change impacts and inform policy."In particular, the new approach suggests that for over 39% of the globe, the computer models either overestimate or underestimate significantly the pace of warming, according to Lovejoy and his co-author, PhD student Raphaël Hébert (now at the Alfred-Wegener-Institut, in Potsdam."Global climate models are important research tools, but their regional projections are not yet reliable enough to be taken at face value," Hébert and Lovejoy asserted. "Historical methods for regional climate projections should be developed in parallel to traditional global climate models. An exciting possibility for further improvements will be the development of hybrid methods that combine the strengths of both the historical and traditional approaches."
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May 15, 2018
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https://www.sciencedaily.com/releases/2018/05/180515105718.htm
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Impact of weather and well-timed cultural management techniques on organic weed control
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Weed management can be a tough challenge in organic cropping systems since growers don't have herbicides in their weed control arsenal. New research published in the journal
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A research team from the USDA's Agricultural Research Service (ARS) evaluated 18 years of weather data collected during a long-term, farming systems project at a site in Beltsville, Maryland. Their objective was to determine which meteorological and management factors most influence weed abundance and whether the impact was direct or indirect.A structural equation analysis showed that precipitation during late vegetative or early reproductive crop growth had a strong positive effect on crop competitiveness, which in turn had an indirect, negative effect on weed cover. In addition, three commonly used cultural practices used in organic crops were found to have a positive impact on crop competitiveness and a negative impact on weeds -- though to a lesser degree than precipitation:"Given the interrelationships of management techniques and weather conditions demonstrated by our analysis, it is clear organic growers need flexible approaches to weed management that respond to shifting conditions and changes in weed populations," says John Teasdale of the USDA ARS Sustainable Agricultural Systems Lab.
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May 15, 2018
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https://www.sciencedaily.com/releases/2018/05/180515105648.htm
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Prized data, free and open to all
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The first official account of the electronic Rothamsted Archive and what it offers, published today, highlights how this unique historical repository of agricultural and meteorological data, which date back to 1843, is the result of some remarkable forward thinking.
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"But if our knowledge of the chemistry of soils should progress as rapidly as it has during the last twenty years, the analysis of a soil will ere long become much more significant than it is at present," note the founders of Rothamsted Research presciently in a paper published in 1864.John Bennet Lawes and Joseph Henry Gilbert began their fertiliser investigations with field experiments in 1843 and, from the start, they kept samples of soil, grain, straw, vegetation and fertiliser, plus data on crop and soil analyses, yields and the weather. More records followed.The accumulated data has always been open and freely available for other researchers to use but the public launch of the electronic Rothamsted Archive (e-RA) in 2013 eased access, and e-RA has steadily become an increasingly well-used and internationally recognised resource.A team of scientists from Rothamsted has now produced a detailed account of the archive as part of a commitment to promote open data, backed by the institute's principal funders, the Biotechnology & Biological Sciences Research Council (BBSRC) and the Lawes Agricultural Trust (LAT). The account is published today in the journal, "Long-time series of data are increasingly valued and are relevant for research into sustainable agriculture, agroecology and food security, as well as for work in modelling, soil science and many other disciplines" says Sarah Perryman, joint e-RA curator and principal co-author."And we're more than just data," adds joint e-RA curator and co-author, Margaret Glendining. "Users have access to supporting specialist background information, such as experimental field plans, fertiliser treatments and key references, and are fully supported by our curating team."The archive holds records of yields of the most important Long-Term Experiments (LTEs) at Rothamsted as well as the longest running, freely available daily weather data in the UK.Staff from e-RA will be demonstrating the archive at an international LTEs conference at Rothamsted next week and at the Festival of Ideas, which marks Rothamsted's 175th birthday, at the end of June."We are managing the e-RA database as a dynamic, developing resource, continually adding to and enhancing it," says Richard Ostler, Agri-Eco Informaticist and co-author, who handles queries about e-RA's open data management. "Importantly, we are working towards FAIR data principles in making the LTE data findable, accessible, interoperable and reusable."The electronic Rothamsted Archive is funded by the LTE National Capability Grant, which also covers the Classical Experiments, the Sample Archive and the Rothamsted Environmental Change Network, and is provided by BBSRC.
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May 15, 2018
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https://www.sciencedaily.com/releases/2018/05/180515081720.htm
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Insurance industry dangerously unprepared for extreme weather, study finds
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As historic flooding caused by climate change devastates communities in New Brunswick and British Columbia, new research from the University of Waterloo reveals the insurance industry hasn't considered a changing climate in their practices, putting homeowners at financial risk.
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The study which looked at data from 178 insurers, found that most insurance companies assumed the risk to property from extreme weather is static and based their premiums on historical data. However, as extreme weather events are increasing in severity, frequency, and unpredictability, insurers have not adjusted."As extreme events become more frequent, insurers that ignore climate change will not put away enough money to cover their claims. To re-coup those losses, they'll have to raise rates or pull coverage from high risk areas," said Jason Thistlethwaite, a climate change economist at the University of Waterloo. "When this shift happens, thousands of people will lose coverage or it will be unaffordable."Another finding in the report outlined how reinsurers, insurers for insurance companies, have been better at reacting and adapting to climate change-related financial risk. This dynamic could lead to significant disruption in global insurance industry."Some insurers are better at understanding climate change than others. These organizations will survive, and likely be able to sell climate services to their counterparts struggling to understand the problem," said Thistlethwaite. "Those that don't, will fail. Insurers are supposed to watch our backs by looking into the future and protect us from unexpected events. We pay to not worry about these things."A full version of the study, "Insurance and Climate Change Risk Management: Rescaling to Look Beyond the Horizon," was published in the
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May 8, 2018
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https://www.sciencedaily.com/releases/2018/05/180508111741.htm
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Bird migration strategies revealed
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Using weather surveillance radar and citizen-science data, researchers are learning how migratory birds return to their breeding grounds in North America each spring with near-pinpoint accuracy. The research focuses on the Central Flyway that runs north-south through the middle of North America -- an aerial superhighway carrying billions of birds northward each spring.
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The new study in the journal "Radar studies have always been limited by their inability to discern species or even groups of species that are flying at night," says lead author Kyle Horton. "We know from radar that massive numbers of migrants are taking to flight each year, but we don't know if those measures are dominated by songbirds or waterfowl. Our study fills that gap by integrating radar data with species-based observations from citizen scientists, via eBird. We're able to reveal behaviors we have never been able to investigate before.""The merger of these two huge datasets, totaling millions of observations from radar sensors and citizen scientists, is an exciting advance," says co-author Benjamin Van Doren of the University of Oxford. "Citizen scientists are the eyes and ears on the ground that radars don't have -- countless new opportunities arise when we bring the two together.""This integration of information at a regional scale provides new insight into conditions that govern behavior of intercontinental-scale migration systems," says co-author Jeffrey Kelly of the University of Oklahoma.This study was conducted with support from the National Science Foundation and Leon Levy Foundation.
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May 3, 2018
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https://www.sciencedaily.com/releases/2018/05/180503142921.htm
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The headache of adapting to the cold, literally
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A common genetic variant implicated in migraine headaches may have proliferated because it helped early humans adapt to cold weather in northern climates. Felix Key of the Max Planck Institute for Evolutionary Anthropology and colleagues report these findings in a new study published May 3rd, 2018 in
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Within the last 50,000 years, some humans left the warm climate of Africa to colonize colder locales in Asia, Europe, and other parts of the world. "This colonization could have been accompanied by genetic adaptations that helped early humans respond to cold temperatures" says Aida Andres, who supervised the study. To find evidence of this adaptation, researchers took a closer look at TRPM8, a gene that codes for the only known receptor that enables a person to detect and respond to cool and cold temperatures. They discovered that a genetic variant upstream from the gene, which may regulate it, became increasingly common in populations living in higher latitudes during the last 25,000 years. Only 5% of people with Nigerian ancestry carry the variant, compared to 88% of people with Finnish ancestry. Currently, the percentage of people in a population that carry the variant increases at higher latitudes and with colder climates. Interestingly, scientists had already identified this variant as being strongly associated with migraine headaches.Migraine is a debilitating neurological disorder that affects millions worldwide. The percentage of people who suffer from the disorder varies across human populations, but is highest in individuals of European descent, which is also the population with the highest frequency of the cold-adaptive variant. The researchers suspect that adaptation to cold temperatures in early human populations may have contributed, to some extent, to the variation in migraine prevalence that exists among human groups today. Felix Key pointed out that "this study nicely shows how past evolutionary pressures can influence present-day phenotypes."
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May 3, 2018
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https://www.sciencedaily.com/releases/2018/05/180503142732.htm
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Temperature swings to hit poor countries hardest
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Temperature fluctuations that are amplified by climate change will hit the world's poorest countries hardest, new research suggests.
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For every degree of global warming, the study suggests temperature variability will increase by up to 15% in southern Africa and Amazonia, and up to 10% in the Sahel, India and South East Asia.Meanwhile, countries outside the tropics -- many of which are richer countries that have contributed most to climate change -- should see a decrease in temperature variability.The researchers, from the universities of Exeter, Wageningen and Montpellier, discovered this "unfair pattern" as they addressed the difficult problem of predicting how weather extremes such as heat waves and cold snaps might change in a future climate."The countries that have contributed least to climate change, and have the least economic potential to cope with the impacts are facing the largest increases in temperature variability," said lead author Dr Sebastian Bathiany, of Wageningen University.Co-author Professor Tim Lenton, from the University of Exeter, added: "The countries affected by this dual challenge of poverty and increasing temperature variability already share half of the world's population, and population growth rates are particularly large in these countries.""These increases are bad news for tropical societies and ecosystems that are not adapted to fluctuations outside of the typical range."The study also reveals that most of the increased temperature fluctuations in the tropics are associated with droughts -- an extra threat to food and water supplies.For their investigation, the team analysed 37 different climate models that have been used for the last report of the Intergovernmental Panel on Climate Change (IPCC).Although climate variability has been studied extensively by climate scientists, the fact that climate variability is going to change has received little attention in fields investigating the impacts of climate change.
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May 2, 2018
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https://www.sciencedaily.com/releases/2018/05/180502104045.htm
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'Hairdryer wind' melts snow in Antarctica in winter as well
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Even though the sun does not shine in Antarctica in winter, in some places snow on the glaciers can melt. The cause: warm wind.
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Utrecht glacier researcher Peter Kuipers Munneke discovered that fact by combining the results of weather stations and satellite images. His findings were published in Winter in Antarctica is pitch black and freezing cold for months on end. In the interior of the continent, temperatures can drop to -80 Celsius. On the coast, however, the winter is usually a bit milder: around -25 degrees Celsius.It now turns out that at those relatively warm spots around the coast, winter temperatures can be even warmer. When the mercury rises above zero, snow begins to melt, causing several meltwater lakes to accumulate on top of the underlying glacier. These lakes can be fifty meters wide, up to a kilometer in length and one or to two meters deep.Glacier researcher Peter Kuipers Munneke from Utrecht University's (UU) climate institute IMAU was the leader of the study in which UU cooperated with several institutes from the UK and the US. Kuipers Munneke was surprised by the findings."The meltwater lakes occur on the Larsen C ice sheet, a large floating glacier in the north of Antarctica, where a large iceberg broke off just last July. We hadn't expected it to melt so much there in the winter, because it's so dark there, and the sun provides absolutely no heat.Four years ago, we installed a weather station there to study why so much snow melts in the area. Unexpectedly, it's due to the melting in the winter, which appears to be caused by the warm wind."Professor Adrian Luckman of Swansea University College of Science said:"Weather station and satellite data show that surface melt on Antarctic ice shelves is not limited to the polar summer. In the winter, when there is no sun, warm winds are providing enough heat to melt snow and cause ponding of liquid water on the surface.These meltwater ponds were a common feature on recently collapsed nearby ice shelves and are thought to affect ice-shelf stability. As global temperatures rise, and the warm winds become more common, this winter melt is likely to occur more often."Dr Suzanne Bevan from Swansea University College of Science said:"This finding is significant because if the ponds cause ice shelves to break up, the glaciers feeding the ice shelves will speed up and discharge more ice from the land to the oceans leading to sea-level rise.Satellite data analysed by Swansea researchers confirms the in-situ observations by automatic weather stations."Around once per week, an extremely warm, dry wind blows down from the mountains to the west of the ice sheet. This foehn wind (German for 'hairdryer') can raise the temperature by 15 to 20 degrees in just a few hours.Kuipers Munneke: "All of the winter heat comes from the foehn wind, there is no other heat source this period of year. During a strong foehn, so much snow can melt that it forms huge lakes on the surface of the ice. We had known about these lakes during the summertime, but apparently 20 to 25 percent of the meltwater from the past few years actually occurs in the winter instead."Kuipers Munneke was first informed of the high temperatures by a colleague in Swansea, UK. "In May 2016, I got an email from Adrian Luckman, the co-author of my article. He wondered if it was indeed true that one of our weather stations had given a temperature reading of eight degrees Celsius. At first, I thought that there was something wrong with the instrument, or that it was a value that needed to be corrected for other weather influences that make it seem warmer than it is. But that wasn't the case. It really was that warm."Kuipers Munneke was grateful to be able to use satellite images provided by the European Space Agency (ESA). "We observed that large meltwater lakes had developed near the weather station. Just a few years ago, the ESA put new satellites into service that can provide much sharper images, and you can see the meltwater lakes very well on the new images. Before, every pixel on a radar image represented an area of five by five kilometres, but with the new satellites, the resolution is closer to 40 by 40 meters. It's as if you traded the camera on your first mobile phone for the latest iPhone 8."Thanks to the new radar images, the researchers can also see that the meltwater re-freezes over the course of the winter. Kuipers Munneke: "Both of the times, the lakes developed in May, the start of the Antarctic winter. Later in the season, the water re-froze, creating slabs of ice over those locations. Consequently, the meltwater doesn't flow into the sea, so it doesn't contribute to rising sea levels either."However, the discovery may have consequences in the future. "Over the past few decades, large floating glaciers have broken off from the Antarctic mainland. That was in some cases caused by the fact that large meltwater lakes had made some of the ice sheets unstable. We may be observing a process that might create meltwater lakes over a much larger area in the future. We expect that there will be many more winter melt days as time passes. Not only because global temperatures are rising, but also because a warmer world means a stronger westerly wind in the southern hemisphere. And that increases the foehn winds that cause winter melting in Antarctica."The results of glacier researcher Kuipers Munneke form a first insight into winter melt on Antarctica. "Thanks to older satellite images, we already had a good idea of the number of winter melt days since 2000. Only now, by combining the new images and exact temperatures, we understand the consequences. However, it is too short a time frame to know whether it happens more frequently now than in the past. This is an initial study, that we can use to compare the volume of winter melting in the future."
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April 25, 2018
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https://www.sciencedaily.com/releases/2018/04/180425162031.htm
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Weather associated with sentiments expressed on social media
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Sentiments expressed on Facebook and Twitter may be associated with certain weather patterns, according to a study published April 25, 2018 in the open-access journal
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Previous research has identified a potential link between weather and people's emotional states, but which specific weather conditions trigger positive or negative emotions and how to measure these sentiments in an accurate and consistent way require further investigation.To examine the association between weather conditions and expressed sentiments, the authors of the present study gathered 2.4 billion posts from Facebook and 1.1 billion from Twitter between the years 2009 and 2016. They analyzed the sentiment for each post using a special tool that categorizes posts based on keywords as positive or negative.The researchers found that temperature, precipitation, humidity, and cloud cover each were strongly associated with an expression of sentiment, whether positive or negative. Positive expressions increase up to 20 degrees Celsius and decline as the temperature goes over 30 degrees Celsius. They also found that precipitation was associated with more negative expressed sentiment. Days with a humidity level of 80% or higher were associated with negative expressions, as were days with a high amount of cloud cover.While the sentiment analysis tool used is imperfect, this study can help provide insight into how weather conditions might impact sentiments expressed via social media, which can act as a proxy for underlying human emotional states. Understanding the potential impact of weather on our emotions is important considering our constant exposure to weather conditions."We find that how we express ourselves is shaped by the weather outside," says Nick Obradovich. "Adverse weather conditions -- hot and cold temperatures, precipitation, added humidity, and increased cloud cover -- reduce the sentiment of human expressions across billions of social media posts drawn from millions of US residents."
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April 24, 2018
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https://www.sciencedaily.com/releases/2018/04/180424112906.htm
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Collapse of the Atlantic Ocean heat transport might lead to hot European summers
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Severe winters combined with heat waves and droughts during summer in Europe. Those were the consequences as the Atlantic Ocean heat transport nearly collapsed 12,000 years ago. The same situation might occur today, according to a new study published in
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Record-breaking cold ocean temperatures across the central North Atlantic in recent years suggest that the northward oceanic heat transport through the Atlantic Meridional Overturning Circulation (AMOC) has reached a long-term minimum and might be the weakest for at least 1,600 years. Most climate models project that the already observed slowdown will continue under global warming scenarios although a complete collapse appears unlikely -- at least based on current models.However, the climate history tells that we do not need to wait for a complete collapse to get a drastic climate response. A new study published in Although the last major climate shock in response to a partial collapse of the AMOC 12,000 years ago took place under quite different conditions, new climate model simulations emphasize a potentially worrisome analogy to today's situation. First, the AMOC collapse takes place in response to a time of rapid warming. Second, while winters become extremely cold, our study shows that European summers might get even warmer. While warm summers do not sound bad, the mechanism leading to this additional warming is responsible for several of the worst heat waves and droughts in Europe.The simulation demonstrates that the mechanism behind this "cold-ocean-warm-summer" feedback is related to so-called atmospheric blocking. This blocking consists of high pressure systems which become quasi-stationary in their position for at least five days or even several weeks. These weather patterns are known to lead to extreme warming and drought in summer or extreme cold waves during winter. These high pressure systems cut Europe off from the warming westerlies in winter or the cooling westerlies in summer and cause the most extreme heat or cold waves. The simulation suggests now that a very cold North Atlantic leads to intensified atmospheric blocking 12,000 years ago and warm summers. The latter is confirmed by new geological evidence in the same study."If the slowdown of the Atlantic overturning proceeds as observed and projected by most climate models for the future, atmospheric blocking might increase in intensity and/or frequency and could lead to even stronger heat waves than we would expect from the gradual warming trend in response to greenhouse gases." says Frederik Schenk, lead author of the study and researcher at Bolin Centre for Climate Research, Stockholm University.
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April 24, 2018
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https://www.sciencedaily.com/releases/2018/04/180424083901.htm
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Winter wave heights and extreme storms on the rise in Western Europe
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Average winter wave heights along the Atlantic coast of Western Europe have been rising for almost seven decades, according to new research.
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The coastlines of Scotland and Ireland have seen the largest increases, with the average height of winter waves more than 10mm/year (more than 0.7metres in total) higher than in 1948.That has also led to increased wave heights during extreme weather conditions, with levels off the Irish coast increasing 25mm/year during the past 70 years, representing an average increase of 1.7m.The study, accepted for publication in They say its findings are important for scientists and coastal managers looking to predict future wave heights, and take measures to protect coastal communities across Western Europe.Dr Bruno Castelle, Senior Scientist at CNRS, said: "The height of waves during winter storms is the primary factor affecting dune and cliff erosion, explaining up to 80% of the shoreline variability along exposed sandy coasts. So any increases in wave heights, and greater frequency of extreme storms, are going to have a major impact on thousands of communities along the Atlantic coastlines of Western Europe. This work and our other recent studies have shown both are on the rise, meaning there is a real need to ensure the Atlantic coasts of Europe are protected against present and future storm threats."The study used a combination of weather and wave hindcasts, and actual data, to measure changes in wave height and variability on coastlines from Scotland in the north to Portugal in the south.These were then correlated against two climate indices -- the North Atlantic Oscillation (NAO), which has long been known to affect climate variability in the Northern Hemisphere, and the West Europe Pressure Anomaly (WEPA), based on atmospheric pressure along the Atlantic coast of Europe.The results showed that all areas had seen an average rise in winter wave heights during this period, although it varied from 10mm/year in Scotland, to 5mm/year in France and 1mm/year in Portugal.The same scientists have previously shown that the winter storms of 2013/14 were the most energetic to hit the Atlantic coast of western Europe since records began in 1948.Professor Gerd Masselink, Lead of the Coastal Processes Research Group at the University of Plymouth, said: "Whether extreme winters such as that of 2013/2014 will repeat more frequently and/or further intensify in the future is a key issue for the Atlantic coast of western Europe. It is therefore important to investigate if these extreme winters are already happening with increasing regularity and intensity, and why this is happening. If human-induced climate change is responsible, we need to seriously start thinking about decreasing our vulnerability to extreme storm events and pro-actively adapt to a more energetic future wave climate.
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April 16, 2018
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https://www.sciencedaily.com/releases/2018/04/180416185617.htm
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General aviation pilots struggle to interpret weather forecast and observation displays
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When tested on their knowledge of 23 types of weather information, from icing forecasts and turbulence reports to radar, 204 general aviation (GA) pilots surveyed by Embry-Riddle Aeronautical University researchers were stumped by about 42% of the questions.
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The findings, published in the April 2018 edition of the Four categories of GA pilots who completed the 95-question exam scored as follows:Overall, the mean score across all 204 pilots was 57.89%, based on assessments conducted on the university's Daytona Beach, Fla., campus and at an air show in the midwestern United States.Improved testing of GA pilots is needed, Blickensderfer said, noting that in 2014, the National Transportation Safety Board named "identifying and communicating hazardous weather" a top priority for improving safety. Currently, however, the U.S. Federal Aviation Administration's Knowledge Exam allows pilots to pass even if they fail the weather portion of the test.She emphasized, however, that her research should not be interpreted solely as a symptom of faulty pilot training. "I don't want to blame the pilots for deficiencies in understanding weather information," she said. "We have got to improve how weather information is displayed so that pilots can easily and quickly interpret it. At the same time, of course, we can fine-tune pilot assessments to promote learning and inform training."As an example, respondents might be prompted to interpret cryptic METAR (Meteorological Terminal Aviation Routine Weather Report) information, which helps pilots prepare for safe flights: "You notice the comment, `CB DSNT N MOV N.' Based on this information, which of the following is true?" Pilots should understand the METAR comment to mean, "Cumulonimbus clouds are more than 10 statute [land-measured] miles north of the airport and moving away from the airport."As another example, pilots might be asked to interpret a ground-based radar cockpit display, which would only show recent thunderstorm activity -- not current conditions. Or, the survey might ask pilots to look at an infrared (color) satellite image and determine where the clouds with the highest-altitude clouds would most likely be found.Thomas A. Guinn, an associate professor of meteorology at Embry-Riddle and a co-author on the study, noted that it's critical for pilots to assess big-picture weather issues before takeoff. In addition, they need to understand, for instance, that radar displayed inside a cockpit shows what happened up to 15 minutes earlier."If you're flying 120 miles per hour and you don't understand that there's a lag time in ground-based radar data reaching your cockpit," Guinn noted, "that can be deadly."All test questions were designed to push pilots beyond whatever facts they had memorized, so that "they had to think about it and answer the question using the same thought processes as if they were performing a pre-flight check," said Robert Thomas, another co-author of the study who is a Gold Seal Certified Flight Instructor and an assistant professor of aeronautical science at Embry-Riddle.The research, supported by $491,000 in funding from the U.S. Federal Aviation Administration, could help guide pilot training and assessments. That's important because pilots can actually pass the FAA's existing Knowledge Exam even if they fail the weather portion of the test.
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April 16, 2018
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https://www.sciencedaily.com/releases/2018/04/180416121526.htm
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How does one prepare for adverse weather events? Depends on your past experiences
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With much of the central plains and Midwest now entering peak tornado season, the impact of these potentially devastating weather events will be shaped in large part by how individuals think about and prepare for them. A new study published in
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Led by Julie Demuth, a scientist from the National Center for Atmospheric Research, the study, "Explicating experience: Development of a valid scale of past hazard experience for tornadoes," characterized and measured people's past tornado experiences to determine their impact on the perceived risks of future tornadoes. Better understanding of these factors can help mitigate future societal harm, for instance, by improving risk communication campaigns that encourage preparation for hazardous weather events.The results indicate that people's risk perceptions are highly influenced by a memorable past tornado experience that contributes to unwelcome thoughts, feelings and disruption, which ultimately increase one's fear, dread, worry and depression. Also, the more experiences people have with tornadoes, and the more personalized those experiences, the more likely they are to believe their homes (versus the larger geographic area of their city/town) will be damaged by a tornado within the next 10 years.In the context of this study, Demuth defines 'past tornado experience' as "the perceptions one acquires about the conditions associated with or impacts of a prior tornado event. Such perceptions are gained by the occurrence of a tornado threat and/or event; directly by oneself or indirectly through others; and at different points throughout the duration of the threat and event."The study was conducted through two surveys distributed to a random sample of residents in tornado prone areas of the U.S. during the spring and fall of 2014. The first survey evaluated an initial set of items measuring experiences, and the second was used to re-evaluate the experience items and to measure tornado risk perceptions. The sample sizes for the two surveys were 144 and 184, respectively.Since tornado experiences can occur at any time throughout one's life, and in multiplicity, the survey items measured both one's most memorable tornado experience and his or her multiple experiences. A factor analysis of the survey items yielded four factors which make up the memorable experience dimensions.The factor analysis revealed two factors contributing to the multiple experience dimensions: common threat and impact communication, and negative emotional responses. The first factor captures one's personal experience with receiving common types of information (e.g., sirens) about tornado threats and tornado-related news. The second factor captures the amount of experience a respondent has with fearing for their own life, a loved one's life and worrying about their property due to a tornado.Individual's past tornado experiences are multi-faceted and nuanced with each of the above six dimensions exerting a different influence on tornado risk perceptions. These dimensions have not been previously analyzed, particularly the intangible aspects -- feelings, thoughts and emotions."This research can help meteorologists who provide many essential, skillful risk messages in the form of forecasts, watches, and warnings when tornadoes (and other hazardous weather) threaten. This research can help meteorologists recognize the many ways that people's past tornado experiences shape what they think and do, in addition to the weather forecasts they receive," states Demuth.
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April 11, 2018
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https://www.sciencedaily.com/releases/2018/04/180411131642.htm
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Atlantic Ocean Circulation at weakest point in 1,600 years
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New research led by University College London (UCL) and Woods Hole Oceanographic Institution (WHOI) provides evidence that a key cog in the global ocean circulation system hasn't been running at peak strength since the mid-1800s and is currently at its weakest point in the past 1,600 years. If the system continues to weaken, it could disrupt weather patterns from the United States and Europe to the African Sahel, and cause more rapid increase in sea level on the U.S. East Coast.
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When it comes to regulating global climate, the circulation of the Atlantic Ocean plays a key role. The constantly moving system of deep-water circulation, sometimes referred to as the Global Ocean Conveyor Belt, sends warm, salty Gulf Stream water to the North Atlantic where it releases heat to the atmosphere and warms Western Europe. The cooler water then sinks to great depths and travels all the way to Antarctica and eventually circulates back up to the Gulf Stream."Our study provides the first comprehensive analysis of ocean-based sediment records, demonstrating that this weakening of the Atlantic's overturning began near the end of the Little Ice Age, a centuries-long cold period that lasted until about 1850," said Dr. Delia Oppo, a senior scientist with WHOI and co-author of the study which was published in the April 12th issue of Lead author Dr. David Thornalley, a senior lecturer at University College London and WHOI adjunct, believes that as the North Atlantic began to warm near the end of the Little Ice Age, freshwater disrupted the system, called the Atlantic Meridional Overturning Circulation (AMOC). Arctic sea ice, and ice sheets and glaciers surrounding the Arctic began to melt, forming a huge natural tap of fresh water that gushed into the North Atlantic. This huge influx of freshwater diluted the surface seawater, making it lighter and less able to sink deep, slowing down the AMOC system.To investigate the Atlantic circulation in the past, the scientists first examined the size of sediment grains deposited by the deep-sea currents; the larger the grains, the stronger the current. Then, they used a variety of methods to reconstruct near-surface ocean temperatures in regions where temperature is influenced by AMOC strength."Combined, these approaches suggest that the AMOC has weakened over the past 150 years by approximately 15 to 20 percent" says Thornalley.According to study co-author Dr. Jon Robson, a senior research scientist from the University of Reading, the new findings hint at a gap in current global climate models. "North Atlantic circulation is much more variable than previously thought," he said, "and it's important to figure out why the models underestimate the AMOC decreases we've observed." It could be because the models don't have active ice sheets, or maybe there was more Arctic melting, and thus more freshwater entering the system, than currently estimated.Another study in the same issue of "What is common to the two periods of AMOC weakening -- the end of the Little Ice Age and recent decades -- is that they were both times of warming and melting," said Thornalley. "Warming and melting are predicted to continue in the future due to continued carbon dioxide emissions."Oppo agrees, both noting, however, that just as past changes in the AMOC have surprised them, there may be future unexpected surprises in store. For example, until recently it was thought that the AMOC was weaker during the Little Ice Age, but these new results show the opposite, highlighting the need to improve our understanding of this important system.
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Weather
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April 10, 2018
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https://www.sciencedaily.com/releases/2018/04/180410164134.htm
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Hotter, longer, more frequent -- marine heatwaves on the rise
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An international study in
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From 1925-2016, the study found the frequency of marine heatwaves had increased on average by 34% and the length of each heatwave had increased by 17%. Together this led to a 54% increase in the number of marine heatwave days every year."Our research also found that from 1982 there was a noticeable acceleration of the trend in marine heatwaves," said lead author, Dr Eric Oliver from Dalhousie University, Canada."While some of us may enjoy the warmer waters when we go swimming, these heatwaves have significant impacts on ecosystems, biodiversity, fisheries, tourism and aquaculture. There are often profound economic consequences that go hand in hand with these events."Some recent examples show just how significant marine heatwave events can be.In 2011, Western Australia saw a marine heatwave that shifted ecosystems from being dominated by kelp to being dominated by seaweed. That shift remained even after water temperatures returned to normal.In 2012, a marine heatwave in the Gulf of Maine led to an increase in lobsters but a crash in prices that seriously hurt the industry's profits.Persistent warm water in the north Pacific from 2014-2016 led to fishery closures, mass strandings of marine mammals and harmful algal blooms along coastlines. That heatwave even changed large-scale weather patterns in the Pacific Northwest.More recently still, Tasmania's intense marine heatwave in 2016 led to disease outbreaks and slowing in growth rates across aquaculture industries.The researchers used a variety of observational datasets to reveal the trend of increasing marine heatwaves, combining satellite data with a range century long datasets taken from ships and various land based measuring stations. They then removed the influences of natural variability caused by the El Nino Southern Oscillation, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation to find the underlying trend."There was a clear relationship between the rise in global average sea-surface temperatures and the increase in marine heatwaves, much the same as we see increases in extreme heat events related to the increase in global average temperatures," said co-author Prof Neil Holbrook from IMAS at the University of Tasmania."With more than 90% of the heat from human caused global warming going into our oceans, it is likely marine heatwaves will continue to increase. The next key stage for our research is to quantify exactly how much they may change."The results of these projections are likely to have significant implications for how our environment and economies adapt to this changing world."
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Weather
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April 10, 2018
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https://www.sciencedaily.com/releases/2018/04/180410084230.htm
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Silent marine robots record sounds underwater
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Silent marine robots that record sounds underwater are allowing researchers at the University of East Anglia (UEA) to listen to the oceans as never before.
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The robots are about the same size as a small human diver, but can reach depths of 1000 metres and travel the ocean for months, covering thousands of kilometres. They communicate by satellite with their pilot to build an underwater soundscape of the world's oceans.Pierre Cauchy, a PhD researcher from UEA's School of Environmental Sciences, has been using one of these autonomous submarines for five years, recording underwater noises in the Mediterranean Sea and the North Atlantic and Southern oceans.The recordings can be used to measure sea-surface wind speed and monitor storms as well as eavesdropping on marine life.Mr Cauchy will present his research at the General Assembly of the European Geosciences Union in Vienna. He will show how the robot -- called a Seaglider -- can measure the wind speed, listen in to the sounds made by fishes and whales, and pick up human activities, such as marine traffic and seismic surveys.By recording sounds in remote locations where there are no permanent weather stations, the robots provide valuable information on wind or storm patterns, which can help to finetune climate models.Mr Cauchy said: "As an acoustician, it is fascinating to listen in to underwater life such as long-finned pilot whales in the North Atlantic, but also to hear the echoes of what is happening in the skies above."While pilot whales make whistles, buzzes and clicks, pods of hunting dolphins create high- pitched echolocation clicks and larger species such as sperm whales make louder, slower clicks.High winds raise the background noise level, seismic surveys' intense pulses are unique and easily identifiable, and marine vessels are clearly identified by low-frequency rumbles.The Seaglider weighs just over 50kg and is 1.5 metres tall. It is remotely controlled by a pilot and is silent, so records only sound from the ocean without adding its own tones.Mr Cauchy said: "Now that they have been shown to be useful for modelling climate, monitoring storms or protecting marine life, I hope that other researchers will integrate the silent robot divers into their work and their use will broaden."
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Weather
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April 2, 2018
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https://www.sciencedaily.com/releases/2018/04/180402160712.htm
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Estuaries may experience accelerated impacts of human-caused CO2
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Rising anthropogenic, or human-caused, carbon dioxide in the atmosphere may have up to twice the impact on coastal estuaries as it does in the oceans because the human-caused CO
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Researchers from the U.S. Environmental Protection Agency and Oregon State University found that there was significant daily variability when it comes to harmful indices of COThese night-time harmful conditions are changing about twice as fast as the daily average, the researchers say, meaning the negative impacts on shell-building animals, including oysters, clams and mussels, may manifest more quickly than expected from simply observing the daily average.Results of the study are being published April 2 in "In these environments that are dominated by marine plants, photosynthesis and respiration cause large differences in CO"The continued addition of COThis is one of the first studies to analyze the dynamics of an estuarine carbonate system on such a fine time scale. Pacella's research focused on an underwater seagrass habitat in Washington state's Puget Sound, which varied between one and four meters in depth. He spent two-and-a-half months monitoring the native eelgrass habitat, which is common to Puget Sound.The researchers say that although the study focused on a habitat in Puget Sound, the results provide an important framework to evaluate other seagrass and estuarine habitats that tend to have lower inherent buffering capacity and large natural variations in chemistry.Pacella, who was lead author on the study, used the detailed data he collected to create a model to estimate the daily carbonate chemistry weather during the summer dry season back to the year 1765, and also projected conditions ahead to 2100 altering the amount of anthropogenic carbon in the system.His measurements and model demonstrates that seagrasses make CO"There is tremendous interest in using marine plants to locally mitigate excess COHowever, the researchers point out that seagrass should be looked at holistically, not just through a carbon budget lens, because it also offers ecological benefits including habitat to marine organisms.Waldbusser has called these changing daily CO"Organisms, including us, experience the weather -- and climate is what causes changes to the weather," Waldbusser said. "However, we can't really 'feel' the gradual change in global temperature. We do, though, experience the extreme weather events or flooding, which are predicted to get worse due to gradual increases in sea level."In this case, the carbonate chemistry history is changing more rapidly than we anticipated. As with sea level rise, the graduate increase becomes more important during events that amplify those otherwise naturally occurring cycles."The researchers say they are still working to better understand how these events -- versus changes in average conditions -- affect the long-term health of species that are sensitive to ocean acidification. There also are implications for how water quality criteria are set."If, as we tend to believe, extreme events matter to marine organisms, the research suggests that more work is needed to define water quality criteria that incorporate daily changes in the highs and lows of CO
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Weather
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April 2, 2018
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https://www.sciencedaily.com/releases/2018/04/180402085901.htm
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Climate change could raise food insecurity risk
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Weather extremes caused by climate change could raise the risk of food shortages in many countries, new research suggests.
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The study, led by the University of Exeter, examined how climate change could affect the vulnerability of different countries to food insecurity -- when people lack access to a sufficient quantity of affordable, nutritious food.Scientists looked at the difference between global warming of 1.5°C and 2°C (compared to pre-industrial levels) and found that -- despite increased vulnerability to food insecurity in both scenarios -- the effects would be worse for most countries at 2°C.The study looked at 122 developing and least-developed countries, mostly in Asia, Africa and South America."Climate change is expected to lead to more extremes of both heavy rainfall and drought, with different effects in different parts of the world," said Professor Richard Betts, Chair in Climate Impacts at the University of Exeter."Such weather extremes can increase vulnerability to food insecurity."Some change is already unavoidable, but if global warming is limited to 1.5°C, this vulnerability is projected to remain smaller than at 2°C in approximately 76% of developing countries."Warming is expected to lead to wetter conditions on average -- with floods putting food production at risk -- but agriculture could also be harmed by more frequent and prolonged droughts in some areas.Wetter conditions are expected to have the biggest impact in South and East Asia, with the most extreme projections suggesting the flow of the River Ganges could more than double at 2°C global warming.The areas worst affected by droughts are expected to be southern Africa and South America -- where flows in the Amazon are projected to decline by up to 25%.The researchers examined projected changes in weather extremes and their implications for freshwater availability and vulnerability to food insecurity.The team included researchers from the Met Office, the European Commission, the Technical University of Crete, Cranfield University and the Rossby Centre in Sweden.
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Weather
| 2,018 |
March 28, 2018
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https://www.sciencedaily.com/releases/2018/03/180328143303.htm
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West Greenland Ice Sheet melting at the fastest rate in centuries
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The West Greenland Ice Sheet melted at a dramatically higher rate over the last twenty years than at any other time in the modern record, according to a study led by Dartmouth College. The research, appearing in the journal
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While natural patterns of certain atmospheric and ocean conditions are already known to influence Greenland melt, the study highlights the importance of a long-term warming trend to account for the unprecedented west Greenland melt rates in recent years. The researchers suggest that climate change most likely associated with human greenhouse gas emissions is the probable cause of the additional warming."We see that west Greenland melt really started accelerating about twenty years ago," said Erich Osterberg, assistant professor of earth sciences at Dartmouth and the lead scientist on the project. "Our study shows that the rapid rise in west Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century."According to research cited in the study, loss of ice from Greenland is one of the largest contributors to global sea level rise. Although glaciers calving into the ocean cause much of the ice loss in Greenland, other research cited in the study shows that the majority of ice loss in recent years is from increased surface melt and runoff.While satellite measurements and climate models have detailed this recent ice loss, there are far fewer direct measurements of melt collected from the ice sheet itself. For this study, researchers from Dartmouth and Boise State University spent two months on snowmobiles to collect seven ice cores from the remote "percolation zone" of the West Greenland Ice Sheet.When warm temperatures melt snow on the surface of the percolation zone, the melt water trickles down into the deeper snow and refreezes into ice layers. Researchers were easily able to distinguish these ice layers from the surrounding compacted snow in the cores, preserving a history of how much melt occurred back through time. The more melt, the thicker the ice layers."Most ice cores are collected from the middle of the ice sheet where it rarely ever melts, or on the ice sheet edge where the meltwater flows into the ocean. We focused on the percolation zone because that's where we find the best record of Greenland melt going back through time in the form of the refrozen ice layers," said Karina Graeter, the lead author of the study as a graduate student in Dartmouth's Department of Earth Sciences.The cores, some as long as 100-feet, were transported to Dartmouth where the research team used a light table to measure the thickness and frequency of the ice layers. The cores were also sampled for chemical measurements in Dartmouth's Ice Core Laboratory to determine the age of each ice layer.The cores reveal that the ice layers became thicker and more frequent beginning in the 1990s, with recent melt levels that are unmatched since at least the year 1550 CE."The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see," said Osterberg. "The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast."Year-to-year changes in Greenland melt since 1979 were already known to be closely tied to North Atlantic ocean temperatures and high-pressure systems that sit above Greenland during the summer -- known as summer blocking highs. The new study extends the record back in time to show that these were important controls on west Greenland melt going back to at least 1870.The study also shows that an additional summertime warming factor of 2.2 degrees Fahrenheit is needed to explain the unusually strong melting observed since the 1990s. The additional warming caused a near-doubling of melt rates in the twenty-year period from 1995 to 2015 compared to previous times when the same blocking and ocean conditions were present."It is striking to see how a seemingly small warming of only 2.2 degrees Fahrenheit can have such a large impact on melt rates in west Greenland," said Graeter.The study concludes that North Atlantic ocean temperatures and summer blocking activity will continue to control year-to-year changes in Greenland melt into the future. Some climate models suggest that summer blocking activity and ocean temperatures around Greenland might decline in the next several decades, but it remains uncertain. However, the study points out that continued warming from human activities would overwhelm those weather patterns over time to further increase melting."Cooler North Atlantic ocean temperatures and less summer blocking activity might slow down Greenland melt for a few years or even a couple decades, but it would not help us in the long run," said Osterberg. "Beyond a few decades, Greenland melting will almost certainly increase and raise sea level as long as we continue to emit greenhouse gases."
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Weather
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March 28, 2018
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https://www.sciencedaily.com/releases/2018/03/180328120055.htm
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Weather phenomena such as El Niño affect up to two-thirds of the world's harvests
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According to researchers at Aalto University, Finland, large-scale weather cycles, such as the one related to the El Niño phenomenon, affect two-thirds of the world's cropland. In these so called climate oscillations, air pressure, sea level temperature or other similar factors fluctuate regularly in areas far apart in a way that causes rain and temperature patterns to shift significantly.
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'During recent years, researchers' ability to predict these oscillations has improved significantly. With this research, we highlight the potential of utilizing this improved forecasting skill in agricultural planning. This could improve the resilience of agriculture to climate related shocks, which can improve food security in many areas across the globe', says Matias Heino, a doctoral candidate at Aalto University.The study, published in These climate oscillations can be divided into different episodes depending on their phase. It is already known that El Niño and its opposite phase, La Niña, have a clear effect on corn, soy, rice, and wheat yields in many areas across South Asia, Latin America and southern Africa.'Our study showed that the North Atlantic Oscillation, NAO, significantly affects crop production in many parts of Europe, but also in North Africa and the Middle East', says assistant professor Matti Kummu from Aalto University.The North Atlantic Oscillation describes the relationship between the Icelandic low pressure and the Azores high pressure areas. When the air pressure in Iceland is significantly lower than in the Azores, stronger winds increase the transport of warm, moist air from the Atlantic to Europe. During the other phase of the North Atlantic Oscillation, when the air pressure difference is smaller, less than average amounts of mild air flow to Europe. It makes the winters colder and less rainy.When the Atlantic air pressure difference has been high, the productivity of crops in Europe have reduced by 2 per cent compared to the average. The effect has been particularly strong in places like Spain and the Balkans, where the decrease in productivity has been as much as 10 per cent. Crop productivity reductions, by up to 6 per cent, were also observed in North Africa and the Middle East. During the other phase of NAO, when the air pressure difference is weaker, the same areas have shown positive changes, in crop productivity.In the Indian Ocean Dipole, the surface water temperature of the Indian ocean fluctuates regularly in the ocean's eastern and western parts: When the surface water is warmer in the Western Indian Ocean, the temperatures in the Eastern Indian Ocean tend to be lower, and vice versa. The IOD phenomenon affects food crop production particularly in Australia, where the crop productivity may, depending IOD's phase, be up to 8 per cent smaller or 6 per cent larger compared to the average.This study has been conducted in collaboration with researchers from Columbia University, Vrije Universiteit Amsterdam, Potsdam Institute for Climate Impact Research (PIK), and University of Bonn.
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Weather
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March 26, 2018
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https://www.sciencedaily.com/releases/2018/03/180326110143.htm
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Alberta's boreal forest could be dramatically altered by 2100 due to climate change
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Half of Alberta's upland boreal forest is likely to disappear over the next century due to climate change, a new study shows.
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The upland forest will be replaced after wildfire by open woodland or grassland, according to research from University of Alberta biologists, conducted in collaboration with Natural Resources Canada researchers."By 2100, at least 50 percent of the boreal upland mixed wood forest could become young deciduous forest and grassland, based on a combination of changes in climate and wildfire," said Diana Stralberg, a recently graduated PhD student in the Department of Biological Sciences.In this study, researchers examined vegetation change as a function of wildfire disturbance and climate change over a 100-year period. Stralberg simulated wildfire using a model from Natural Resources Canada and used data from the Alberta Biodiversity Monitoring Institute to determine what vegetation might grow back under future climates.Repeating this cycle over a 100-year period painted a bleak picture -- approximately half of Alberta's upland boreal forest would eventually be replaced by young deciduous forest and grasslands. Boreal wetlands were not included due to uncertainty regarding their long-term persistence.The results may actually be on the conservative side, as they do not take into account human activity, drought, or insects, explained Stralberg, who began the study as a PhD student under the supervision of Professor Erin Bayne. Business as usual"Our model assumes 'business as usual' in the province, with high carbon emissions and climate change continuing at the current rate. So societal action can still reduce this risk," said Stralberg."Although fire is a natural component of this ecosystem, the irreversible loss of old forest could have detrimental effects on many species, including many resident and migratory songbirds. The dry climate of the western boreal region makes it particularly vulnerable to climate change."As ecosystems are disturbed by wildfire, climate change affects which vegetation types will grow back. Climate change also affects the potential for wildfires to occur through changes in weather. Climate models indicate that climate conditions that are currently associated with prairies, rather than forests, will dominate the region by the end of the 21st century, making it inhospitable for regrowth of coniferous forest. Meanwhile, existing trees will continue to provide fuel for large fires for several decades.In order to anticipate and adapt to climate change, land managers must better understand how landscapes are likely to change in the future. And, while not a crystal ball, models like this one make it possible to glimpse into the future and plan for a range of potential outcomes.
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Weather
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March 23, 2018
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https://www.sciencedaily.com/releases/2018/03/180323141334.htm
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Arctic wintertime sea ice extent is among lowest on record
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Sea ice in the Arctic grew to its annual maximum extent last week, and joined 2015, 2016 and 2017 as the four lowest maximum extents on record, according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) and NASA.
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On March 17, the Arctic sea ice cover peaked at 5.59 million square miles (14.48 million square kilometers), making it the second lowest maximum on record, at about 23,200 square miles (60,000 square kilometers) larger than the record low maximum reached on March 7, 2017.More significantly from a scientific perspective, the last four years reached nearly equally low maximum extents and continued the decades-long trend of diminishing sea ice in the Arctic. This year's maximum extent was 448,000 square miles (1.16 million square kilometers) -- an area larger than Texas and California combined -- below the 1981 to 2010 average maximum extent.Every year, the sea ice cover blanketing the Arctic Ocean and surrounding seas thickens and expands during the fall and winter, reaching its maximum yearly extent sometime between late February and early April. The ice then thins and shrinks during the spring and summer until it reaches its annual minimum extent in September. Arctic sea ice has been declining both during the growing and melting seasons in recent decades.The decline of the Arctic sea ice cover has myriad effects, from changes in climate and weather patterns to impacts on the plants and animals dependent on the ice, and to the indigenous human communities that rely on them. The disappearing ice is also altering shipping routes, increasing coastal erosion and affecting ocean circulation."The Arctic sea ice cover continues to be in a decreasing trend and this is connected to the ongoing warming of the Arctic," said Claire Parkinson, senior climate scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's a two-way street: the warming means less ice is going to form and more ice is going to melt, but also, because there's less ice, less of the sun's incident solar radiation is reflected off, and this contributes to the warming."The Arctic has gone through repeated warm episodes this winter, with temperatures climbing more than 40 degrees above average in some regions. The North Pole even experienced temperatures above the freezing point for a few days in February.In mid-March, cooler temperatures and winds pushed out the edge of the sea ice pack and caused a late surge in ice growth that brought the maximum extent closer in line with the past few years.In February, a large area of open water appeared in the sea ice cover north of Greenland, within the multiyear ice pack -- the Arctic's oldest and thickest ice. Most of the opening has refrozen but the new ice is expected to be thinner and more fragile, and a new opening might appear during the melt season. This could make the ice in this region more mobile and prone to exiting the Arctic this summer through either the Fram or Nares straits, ultimately melting in the warmer waters of the Atlantic Ocean."This old, thicker ice is what we expect to provide stability to the Arctic sea ice system, since we expect that ice not to be as vulnerable to melting out as thinner, younger ice," said Alek Petty, a sea ice researcher at Goddard. "As ice in the Arctic becomes thinner and more mobile, it increases the likelihood for rapid ice loss in the summer."Despite the fact that this year's melt season will begin with a low winter sea ice extent, this doesn't necessarily mean that we will see another record low summertime extent."A lot will depend on what the wind and temperature conditions will be in the spring and summer," Parkinson said.Starting March 22, Operation IceBridge, NASA's aerial survey of polar ice, is flying over the Arctic Ocean to map the distribution and thickness of sea ice. In the fall, NASA will launch a new satellite mission, the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2), which will continuously monitor how sea ice thickness is changing across the Arctic.For NSIDC's analysis:
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March 21, 2018
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https://www.sciencedaily.com/releases/2018/03/180321130859.htm
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New data confirm increased frequency of extreme weather events
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New data show that extreme weather events have become more frequent over the past 36 years, with a significant uptick in floods and other hydrological events compared even with five years ago, according to a new publication, "Extreme weather events in Europe: Preparing for climate change adaptation: an update on EASAC's 2013 study" by the European Academies' Science Advisory Council (EASAC), a body made up of 27 national science academies in the European Union, Norway, and Switzerland. Given the increase in the frequency of extreme weather events, EASAC calls for stronger attention to climate change adaptation across the European Union: leaders and policy-makers must improve the adaptability of Europe's infrastructure and social systems to a changing climate.
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Globally, according to the new data, the number of floods and other hydrological events have quadrupled since 1980 and have doubled since 2004, highlighting the urgency of adaptation to climate change. Climatological events, such as extreme temperatures, droughts, and forest fires, have more than doubled since 1980. Meteorological events, such as storms, have doubled since 1980.These extreme weather events carry substantial economic costs. In the updated data, thunderstorm losses in North America have doubled -- from under US$10 billion in 1980 to almost $20 billion in 2015. On a more positive note, river flood losses in Europe show a near-static trend (despite their increased frequency), indicating that protection measures that have been implemented may have stemmed flood losses.Professor Michael Norton, EASAC's Environment Programme Director states, "Our 2013 Extreme Weather Events report -- which was based on the findings of the Norwegian Academy of Science and Letters and the Norwegian Meteorological Institute -- has been updated and the latest data supports our original conclusions: there has been and continues to be a significant increase in the frequency of extreme weather events, making climate proofing all the more urgent. Adaptation and mitigation must remain the cornerstones of tackling climate change. This update is most timely since the European Commission is due to release its evaluation of its climate strategy this year."Is a contemporary shutdown of the Gulf Stream (AMOC) possible?The update also reviews evidence on key drivers of extreme events. A major point of debate remains whether the Gulf Stream, or Atlantic Meridional Overturning Circulation (AMOC), will just decline or could 'switch off' entirely with substantial implications for Northwest Europe's climate. Recent monitoring does suggest a significant weakening but debate continues over whether the gulf stream may "switch off" as a result of the increased flows of fresh water from northern latitude rainfall and melting of the Greenland icecap. EASAC notes the importance of continuing to use emerging oceanographic monitoring data to provide a more reliable forecast of impacts of global warming on the AMOC. The update also notes the recent evidence which suggests an association between the rapid rate of Arctic warming and extreme cold events further south (including in Europe and the Eastern USA) due to a weakened and meandering jet stream.
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March 21, 2018
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https://www.sciencedaily.com/releases/2018/03/180321121600.htm
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New interactive map shows climate change everywhere in world
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What does Salt Lake City have in common with Tehran? More than you might think, if you're a climate scientist.
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University of Cincinnati geography professor Tomasz Stepinski created a new interactive map that allows students or researchers to compare the climates of places anywhere in the world. The map draws on five decades of public meteorological data recorded from 50,000 international weather stations around the Earth.The data is mapped in a 4-square-kilometer grid that gives researchers a visual of what's happening with temperatures and precipitation from pole to pole."The map demonstrates climate change over time but also climate diversity. The concept is powerful and can inspire a lot of research," Stepinski said.Stepinski has spent his career studying spatial, societal and temporal patterns in his Space Informatics Lab in the McMicken College of Arts and Sciences. His late map project in 2017 examined the racial diversity of every neighborhood in America. The digital magazine Quartz called the map "insanely detailed."Stepinski, a native of Poland, has long been interested in climate and other natural phenomenon that are studied with statistics."I've lived in Houston, Tucson and Cincinnati. Climatically speaking, they couldn't be farther apart," he said.For this project, Stepinski teamed up with Polish researcher Pawel Netzel, who worked in Stepinski's lab at UC. Using monthly records from the public database WorldClim, they developed a visual way for researchers to study patterns and variability of climate over time from locations virtually anywhere in the world.The map, called ClimateEx, also allows researchers to study what areas of the globe have seen the most dramatic changes in climate over time. Not surprisingly, this includes portions of the warming arctic. But perhaps surprisingly the map also demonstrates that the tropics around the equator also have seen big changes. Stepinski said this is due not to variations in temperature but in monthly rainfall."When people think about climate change, they think about temperature: global warming," he said. "But climate has many components, including precipitation. People often consider temperature and precipitation separately. But our mathematical model includes both."Netzel said the map is especially useful at comparing and contrasting unrelated or geographically distant places since month-to-month weather can vary widely depending on the seasons."ClimateEx is mostly an educational tool," Netzel said. "Using ClimateEx, it is easy to get answers to questions such as where in the world do we have a climate similar to Houston's? Where can I find a place with a climate as pleasant as Florida's?"The map also could help predict which areas will have climates more conducive to extreme weather phenomena such as tornadoes in places where historically there were few, he said."ClimateEx enables an easy search for locations where climate change may lead to the occurrence of such extreme phenomena in the future," he said. "The user simply indicates the location where tornadoes are presently frequent and ClimateEx finds all locations where in 50 years the climate will be conducive to tornadoes."Stepinski and Netzel wrote about their map project in an article this month in the "The climate is always changing," Stepinski said. "But it usually changes on a geological timescale. It's not surprising that the climate today is different from the climate a half-million years ago. But now we're experiencing changes on a scale of 100 years. That's a completely different thing."A warmer climate means there is more energy in the atmosphere. This is leading to increasing frequency and severity of storms and longer droughts according to the U.S. Global Change Research Program, a collaboration of government agencies. That panel's 2017 report concluded that the planet is warming because of human activity, primarily the burning of fossil fuels, since the Industrial Revolution."If you were looking at climate change at a scale of a million years, you wouldn't worry too much," Stepinski said. "But if you see dramatic changes on the order of a few decades, it's a big problem. Personally I'm not happy there are people who seem to disregard this as not much of a problem. It is a problem."Netzel said the map isn't designed specifically for emergency planning. But after seeing what the future might hold, the map could be useful, he said."It can support strategic, long-term planning and decision-making on the future development of urbanized space," he said. "It helps to prepare for emerging threats such as increasing the frequency or appearance of extreme weather phenomena. Knowledge about the possibility of hazards will give city planners time to prepare appropriate response plans."But Stepinski said the map is easy enough to use and understand that ordinary people could use it for more personal reasons like planning their next vacation or contemplating a move to a new city.So what's the global climate twin of Cincinnati?Stepinski said it's Vicenza, Italy."You will see that both Cincinnati's and Vicenza's climates have a similar progression of weather conditions throughout the year," he said. "So a person would experience the passing of the seasons in the same way in both places."Map:
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March 21, 2018
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https://www.sciencedaily.com/releases/2018/03/180321091016.htm
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Pacific influences European weather
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Sea surface temperature in the distant tropical Pacific can influence November weather in Europe.
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This is shown in a new study led by Martin King at the Bjerknes Centre and Uni Research. King and his team have explored whether conditions in the Pacific allow us to predict months ahead whether fall and winter in Europe will be warm or cold, dry or wet.During El Niño events, warmer surface water in the east Pacific Ocean changes the world's weather. This phenomenon occurs every two to seven years and -- after the seasonal changes -- accounts for the largest variations in the world's weather. El Niños are linked to droughts in Australia and East Africa, and to floods in Peru.How much Europe is affected is still an open question. Previous research has focused mostly on the winter months, when the El Niño phenomenon is the strongest. The new study shows that, in Europe, the effect on weather is still stronger in fall. Martin King and his colleagues find that El Niños are associated with wetter and warmer weather in large parts of Europe in November.Martin King hopes that renewed interest in the seasonal variation of El Niño tele-connections in Europe will contribute to further progress in climate predictions on monthly and seasonal scales."Predictions of the El Niño in winter are already very good. The summer before, we will know," says King.Predictions of weather and climate for months, seasons and decades ahead lie between normal weather forecasts and climate projections for the coming century -- concerning both what influences the climate on these time-scales, and the methods required to make such predictions.Changes in the oceans occur more slowly than in the atmosphere, and this long-term memory of the ocean is a major key to seasonal and decadal predictions. Pacific temperature patterns like El Niño is only one of the factors that can affect weather in Europe on long-term scales. Other players are sea surface temperature in the Atlantic, Arctic sea ice, Eurasian snow cover and conditions in the stratosphere, high above what we normally consider as weather.Bjerknes Centre, Uni Research and University of Bergen scientists Noel Keenlyside, Stefan Sobolowski and Camille Li are among King's co-authors, as are colleagues from the University of Zagreb, the University of Barcelona, Barcelona Supercomputing Center and the Abdus Salam International Centre for Theoretical Physics in Trieste.
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March 21, 2018
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https://www.sciencedaily.com/releases/2018/03/180321090417.htm
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The Arctic sea-ice loss and winter temperatures in Eurasia
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A long debate of the role of the sea ice and the winter temperatures in Eurasia has got a new contribution. Probably no connection, a new study says.
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The Arctic warming and the decline of the polar sea ice, do these phenomena have a connection to the cooling trends of winter in the Eurasia?In a new publication, a group of researchers at the Bjerknes Centre for Climate Research have studied this connection together with collagues in Sweden, Denmark, China, France, Japan and Russia.In the scientific community it has been a debate on the connection between the role of the Arctic sea-ice loss and climate changes in the Northern Hemisphere. Previous modeling studies have suggested widely different findings.Observations show a clear warming in the Arctic waters together with loss of sea ice, also in wintertime. But in Siberia in winter, the trend is the opposite. Over a decade the trend is cooling temperatures in the northern parts of Eurasia.So is there a connection between these two phenomena? Probably not, according to Fumiaki Ogawa, first author in the newly published study."The results indicate that the impact of the recent sea-ice decline is rather limited to the high-latitude lower troposphere in winter, and the sea-ice changes do not significantly lead to colder winters over Siberia," the authors writes.To try to resolve the controversy, Fumiaki Ogawa and collegaues tried a new way to look at the controversy. With coordinated experiments with six atmospheric general circulation models, forced by observed daily sea-ice concentration and sea surface temperatures."In our study we used satellite data for sea ice and sea surface temperatures to run some coordinated hindcast experiments with five different atmospheric models," Ogawa says.To run several models together is called a multi-model approach. The mean of the model ensemble is reducing biases of each model and provides the best estimate of the signal of the polar sea ice loss.The results suggest that the impact of sea ice seems critical for the Arctic surface temperature changes, but the temperature trend elsewhere seems rather due mainly to changes in ocean surface temperatures and atmospheric variability.
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Weather
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March 20, 2018
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https://www.sciencedaily.com/releases/2018/03/180320123458.htm
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Study of climate change could lead to understanding future of infectious disease
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Over the past 34 years, rainfall in Uganda has decreased by about 12 percent even though many of the global climate models predict an increase in rainfall for the area, according to an international team of researchers. Rainfall levels in Uganda impact agriculture, food security, wildlife habitats and regional economics as well as the prevalence of certain diseases.
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"We didn't plan to study the climate," said Steven J. Schiff, Brush Chair Professor of Engineering in the Departments of Neurosurgery, Engineering Science and Mechanics and Physics, Penn State. "But we realized we needed the information to study infections. The biggest need for infant brain surgery in the developing world is infection-caused hydrocephalus."While there are congenital cases of hydrocephalus, infectious disease causes the majority of cases in Uganda. Infections are the cause of large numbers of infant deaths during the first four weeks of life and half those deaths take place in sub-Saharan Africa. Those who do not die, often develop hydrocephalus, a buildup of fluids in the brain cavities that can cause head deformation and cognitive deficits. It is estimated that there are 100,000 to 200,000 such cases each year in sub-Saharan Africa."Previous research showed that intermediate levels of rainfall are associated with peaks in the number of cases of hydrocephalus," said Schiff. "We had to take a careful look at rainfall. We had county-level information, but we had to get down to the village level."Paddy Ssentongo, assistant research professor, Center for Neural Engineering and Engineering Science and Mechanics, Penn State, worked with several government agencies in Uganda to establish a collaboration. Using census data, election data and village boundary information, combined with weather and climate data from the African desk of the U.S. National Oceanic and Atmospheric Administration, they managed to fuse village details with satellite rainfall data over the past 34 years. They reported their results in a recent issue of "Uganda is a developing country dependent on rain-fed agriculture," said Ssentongo. "If it depends on agriculture then you look at rainfall. If rainfall isn't dependable, farmers lose crops."Another consideration, according to Ssentongo, is that understanding the fluctuations in rainfall can help municipalities and national governments plan infrastructure to improve growth and the economy. Resilience needs to be built into agricultural planning to adjust to the decrease in rainfall in the greater Horn of Africa over these past four decades. In addition, the Bwindi Impenetrable National Park in Southwest Uganda is also affected by the drier climate and the Bwindi Forest is the last habitat of the mountain gorilla.For these reasons, the Ugandan government was very interested in fully understanding the climate data and supplied detailed geospatial data so they could have location-specific climate data for planning.The researchers found that the rainfall predicted for East Africa on a decadal scale by models using the effects of the El Niño Southern Oscillation and the Indian Ocean Dipole did not account for as much of the rainfall fluctuations as expected for the past 34 years. This is in part because the rainfall fluctuations fall during shorter timespans than decades.Uganda has two rainy seasons, one from March to May and one from October to December. The rainy seasons have higher malaria rates, but are also related to a variety of bacterial and viral infections that have seasonal and rainfall related rates. Hydrocephalus also has a pattern related to the rainfall seasons which varies by location."With climate data at this level, we can pinpoint the address of every baby with hydrocephalus and correlate that to a square on the satellite rainfall maps," said Schiff. "We can know how much rain had been falling on that address when the infant became ill."The researchers' goals are to identify vulnerable areas for epidemic diseases, particularly neonatal sepsis and through this identification develop ways to prevent and treat these diseases."We can't track the disease causes unless we take the major environmental conditions into account," said Schiff.
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