Climate variability leads to more intense thunderstorms • Earth.com

Climate variability leads to more intense thunderstorms In a new study by Texas A&M University, experts report that large thunderstorms in the southern Great Plains of the United States have increased in frequency and intensity. The researchers found that these changes are linked to climate variability.

“Thunderstorms in the southern Great Plains of United States are among the strongest on Earth and have increased in intensity and frequency in recent years, ”the researchers explained.

“Assessing changes in storm characteristics under different climate scenarios, however, remains very uncertain due to the limitations of the physics of climate models. “

The current study focused on isotopes from stalactites in Texas caves dating back between 30,000 and 50,000 years. The researchers analyzed the oxygen isotopes contained in the stalactites to identify trends from past thunderstorms.

“Storm regimes shift from weakly to strongly organized over millennial time scales and coincide with well-known abrupt climate changes during the last ice age,” the study’s authors found.

“Modern synoptic analysis suggests that the organization of thunderstorms in the southern Great Plains is strongly related to changes in large-scale wind and humidity patterns.”

Understanding these changes will not only help reconstruct past storm patterns, experts say, but will also help predict mid-latitude patterns that will emerge in decades to come.

“Proxy recordings are available in the southern great plains in caves,” study co-author Christopher Maupin said. “There are probably thousands of caves in the southern Great Plains and southern Texas. Why has there not been more research in these areas? Cave deposits are so promising as a proxy.

Study co-author Courtney Schumacher said scientists understand modern precipitation models. “However, we don’t know what will happen in the future, and this work will help predict storm trends in the future,” Schumacher said. Climate variability leads to more intense thunderstorms

“If we can run a climate model for the past that is consistent with the cave records, and run that same model in the future, we can have more confidence in its findings if it matches the cave records than if they were. are not. On two models, if one really matches the isotopes of the cave, you can trust that one to understand the distribution of storms in the future. “

“There are some really important questions about what has happened in the past regarding the large weather events we experience through mesoscale convective systems (large storms) versus non-mesoscale things (small storms).”

“We get so much precipitation from really big storms, and the model grids can’t capture big weather events because the grids themselves are so big. Paleoclimatology helps organize past events to develop an indirect record of how they react to average climate. “

Schumacher noted that large storms that cover hundreds of miles provide about 50 to 80 percent of rainfall in Texas.

“These thunderstorms are so big that even though most of the rain occurs in Oklahoma, the rain in Texas will still carry the isotopic signature of these huge storms,” said Maupin.

“You take fingerprints from these systems wherever they are, and they don’t need to be super-localized to be recognized. Large storms cause depleted isotope signatures. You cannot explain the variability of stalactites by temperature changes alone.

The study is published in the journal Geosciences of nature.

Through Chrissy sexton, Terre.com Editor-in-chief


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More intense and frequent thunderstorms linked to global climate variability – sciencedaily

Heavy thunderstorms in the southern Great Plains of the United States are among the strongest on Earth. In recent years, these storms have increased in frequency and intensity, and new research shows that these changes are linked to climate variability.

Co-authored by Christopher Maupin, Courtney Schumacher and Brendan Roark, all scientists from Texas A&M University’s College of Geosciences, along with other researchers, the results were recently published in Natural geosciences.

In the study, the researchers analyzed the oxygen isotopes of 30,000-50,000-year-old stalactites from Texas caves to understand the trends of past thunderstorms and their durations, using a radar calibration for the isotopes of the storms. precipitation in the region. They found that when storm regimes shift from weakly to strongly organized over millennial time scales, they coincide with well-known global abrupt climate changes during the last ice age, which occurred about 120,000 ago. at 11,500 years.

Through modern synoptic analysis, researchers have learned that thunderstorms in the southern Great Plains are strongly related to changes in wind and humidity regimes occurring on a much larger scale. Understanding these changes and various correlations will not only help reconstruct past thunderstorm occurrences, but will also help predict future mid-latitude thunderstorm patterns.

“Proxy recordings are available on the southern great plains in the caves,” Maupin said. “There are probably thousands of caves in the southern Great Plains and southern Texas. Why hasn’t there been more research in these areas? Cave deposits hold so much promise as a proxy. “

Schumacher said scientists understand modern precipitation patterns and that large storms can deplete isotopes.

“However, we don’t know what will happen in the future, and this work will help predict storm trends in the future,” she said. “If we can run a climate model for the past that is consistent with the cave records, and run that same model in the future, we can have more confidence in its conclusions if it matches the cave records than if they do not. On two models, if one really matches the isotopes of the cave, you can trust that one to understand the distribution of storms in the future. “

Caves hold little-known climatic records

Maupin, a paleoclimatologist, described the limitations that exist in capturing the true distribution of weather events over time.

“There are some really important questions about what has happened in the past regarding the large weather events we experience through mesoscale convective systems (large storms) versus non-mesoscale things (small storms),” he said. declared Maupin. “We get so much precipitation from really big storms, and the model grids can’t capture big weather events because the grids themselves are so big. Paleoclimatology helps organize past events to develop an indirect record of how they react to average climate. “

Maupin collaborated with National Taiwan University to do a uranium and thorium dating and found that the stalactites and stalagmites actually dated from the Ice Age.

Interdisciplinary collaboration

Schumacher’s expertise was needed to make connections with various rainy events that occurred over time. She had experience with radar data and global rainfall measurements.

“Large storms that cover hundreds of miles provide about 50 to 80 percent of rain in Texas,” Schumacher said. “These storms today have different isotopic signatures. “

Maupin’s research pushes back on outdated paleo-world principles, as you need to study how storms grow bigger and what influences them, he said.

“These thunderstorms are so big that even though most of the rain occurs in Oklahoma, the rain in Texas will still carry the isotopic signature of these huge storms,” said Maupin. “You fingerprint these systems no matter where they occur, and they don’t need to be super localized to be recognized. Big storms cause depleted isotope signatures. You can’t explain the variability of stalactites. with the only temperature changes. “

Research Experience for Aggie Undergraduates

Celia Lorraine McChesney ’16 and Audrey Housson ’16 were two undergraduate researchers involved in this publication, and both learned a lot through fieldwork, collaboration and the high impact learning experience.

“The cave samples have been used as a high-impact learning tool to understand the paleoclimate of Texas,” said Maupin. “One of the undergraduates started micro-milling the stalactites. I was very fortunate to have access to the resources of the College of Geosciences and to work with these talented undergraduates on groundbreaking research. “

McChesney said his experience working on his graduation thesis at the lab was “invaluable” and the research has allowed him to travel and go into the field.

“As an undergraduate research student at Texas A&M, I was proud to be part of one of the first teams to correlate climate change and weather links in a paleoclimatic dossier,” said Housson. “All this experience allowed me to discover the academic world and made me more confident as a scientist. Now, as a geologist and civil engineer, I work on heavy civil infrastructure projects like tunnels and dams related to water resources. I love how my career ties into my undergraduate research where knowing the correlation between climate change and weather helps plan water resources in the future. “

Funding for this research was provided in part by a High Impact Undergraduate Research Grant from Texas A&M University.


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Predictions of climate variability and effects on agriculture – BC Local News

As I sit down to write this, it is with the heaviness of the news that a family friend has been found deceased. This leaves those closest to you wondering what more they could have done to reach out.

Oliver Rujanschi, we will miss you and the warmth you were. Sorry friend!

And we are all moved by the tragic depth of the discovery of so many innocent children buried at Kamloops Residential School.

***

A few years ago, many of us interested in the impacts of climate change got together with the Government of British Columbia’s Climate Action Unit of the Ministry of Agriculture, to define a strategy for cope with the expected impacts.

The temperature projections for 30 years (2050) were 2.1 to 4.1 degrees Celsius in annual mean temperatures. This comes with an additional 35-64 frost-free days.

On the precipitation front, one would expect an increase of 5.1% per year and a decrease of 27% falling as snow. In all likelihood, summers will be drier.

Extremes can involve and increase the frequency and magnitude of extreme precipitation events. The average number of days above 30C will increase each year.

With this information in hand, producers and stakeholders identified the top five climate issues.

First, there has been the increased risk of forest fires. The region then experienced significant forest fire seasons in 2009, 2010 and 2012. Subsequently, 2017 and 2018 saw record fires, burning 1.1 million hectares (over two million acres ).

Second, changing hydrology affects us in the following ways: Hotter, drier summers have reduced water supplies while increasing water requirements for crops and livestock. The summers of 2019 and 2020 saw a number of farms and ranches hit hard by the flooding.

Third, increased variability was of great concern to growers, in particular: unpredictable storms, temperature / precipitation fluctuations and extremes, and freeze-thaw cycles.

Fourth, changes in pests, diseases and invasive species are upon us. Although we know the impacts of the mountain pine beetle, we do know that fire ants, cutworms and gray moth are increasingly important. This is in part due to the warmer winters.

Fifth, there will be changes in wildlife and ecological systems: the ecological communities and water resources of the Cariboo rangelands change, which alters forage productivity.

On all these fronts, producers and the government have made progress on projects.

There is much more to report and I direct interested readers to Climate Action Agriculture at www.climateagriculturebc.ca/regional-adaptation/cariboo/.

Many projects are showcased there.

Producer leaders have worked hard with governments to oversee studies and trials designed to benefit food production in our home region.

When we have the certainty of a tragedy to come, or even mere suspicion, we owe it to our fellow human beings to act. The same is true of the past and future human, personal and societal tragedies to which I alluded in my opening lines.

Soil is the skin of the Earth organism. Human health and the health of the Earth are one.

David Zirnhelt is a breeder and member of the Cariboo Cattlemen’s Association. He is also chairman of the advisory committee for the sustainable breeding program applied to TRU.

Quesnel Cariboo Observer


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Scientists study how regional climate variability affects animals in arid North America: UNM Newsroom

As visual evidence of climate change continues to shed light on a huge problem in the world, scientists studying at several National Science Foundation (NSF) Long-Term Ecological Research (LTER) sites are partly addressing the problem. problem by examining changes in the diversity and abundance of small mammals to understand their vulnerabilities to climate change.

Long-term regional monitoring can improve detection of biodiversity declines associated with climate change by combining information from both temporal and spatial dimensions. In the drylands of North America, future climate predictions include a nearly 100 percent chance of a decadal drought, the impacts of which will be magnified by ongoing global warming. Drylands are regions constrained by water scarcity and are essential for understanding how climate change affects biodiversity, as they cover 45 percent of the earth’s surface.

Ord’s kangaroo rat (Dipodomys ordii) is a grassland species present in all long-term study areas of the arid zones of our study. Like many rodent species we studied, D. ordii’s responses to drought conditions varied among sites and ecosystem types. Photo credit: Nicole Kaplan

In a study published today in Global Change Biology titled “Decline in rodent abundance and diversity follows regional climate variability in the drylands of North America“, a group of scientists are trying to understand long-term changes in the diversity and abundance of small mammals and identify species that may be most sensitive to our drier, less predictable climate.

“Over the past 100 years in the southwestern United States, our climate has become drier and more variable, with increasing differences in drought index from year to year.” said Jennifer Rudgers, professor of biology at the University of New Mexico, senior author. and director and principal investigator of the Sevilleta Long Term Ecological Research (SEV LTER) Program in New Mexico. “Increasing climate variability is an aspect of climate change that has not been studied as extensively as changes in average temperature such as the climate becoming, on average, warmer or drier. Yet most climate predictions for the future include the prediction of increasing variability. ”

As part of the study, scientists analyzed abundance data from 22 rodent species in grassland, scrub, ecotone, and forest ecosystems in the southwestern United States as part of a time series (1995-2006 and 2004-2013) representing the Pacific phases. Decadal oscillation (PDO). PDO influences drought in southwestern North America, where rodents are diverse and important consumers.

The study, which took place at LTER sites from the northern Chihuahuan Desert to the southern Great Plains of western North America, combined 12 datasets on eight ecosystem types to examine the models. temporal diversity, composition and abundance of rodent species at the regional scale.

Data gathering

Sevilleta National Wildlife Refuge Branch Fellows Ariel Elliott is recording data on a kangaroo rat. Photo credit: Kathy Granillo

“Long-term observations that occur during periods with varying climates have allowed us to look for non-linear relationships between mammalian abundance and climatic variables,” Rudgers explained. “Non-linearities give signals about the sensitivity of species to climate variability. Because our climate is quite variable, we could capitalize on this inherent variability to detect past patterns that can predict the future. “

A key element that impacted the study was the Pacific Decadal Oscillation (PDO) and the role it plays in climate change. PDO is a climatic phenomenon that occurs when the sea surface waters in the northern Pacific Ocean fluctuate in temperature. This is an often decades-long oscillation that affects precipitation in the southwestern desert. When the surface temperatures of the Pacific Ocean along the west coast of North America are warm, the southwestern United States is generally in a phase of drought. When surface waters are cool, they tend to be wetter in the southwest.

“Because we had long-term small mammal abundance datasets (almost 20 years of data), we were able to separate our dataset into two time periods that each covered a phase of AOP: one wetter and earlier period in the mid-1990s-early 2000s and a drier, later period (2004-2013), ”said Rudgers. “This allowed us to explore how the climatic sensitivities of small mammals have changed over time, in concert with different phases of AOP.”

Using a climate sensitivity function approach developed by the team, scientists were able to comb through long-term observations that occurred during periods with varying climates to look for non-linear relationships between the abundance of mammals and climatic variables.

WER1 stamp

UNM is the only R1 in New Mexico: doctoral university with very high research activity as classified by the Carnegie Commission on Higher Education.

“We detected regional trends in our New Mexico, Colorado, and Arizona data sets,” Rudgers said. “Regionally, the diversity of rodent species has declined by 20 to 35 percent, with greater losses in the subsequent period. The abundance has also declined regionally, but only recently, with losses of 5 percent of the animals we have captured and released.

However, Rudgers noted that these declines in diversity varied across ecosystem types and locations. “The greatest declines in diversity have occurred in three types of ecosystems: the juniper pine forests and creosote shrub areas of the Sevilleta National Wildlife Refuge in New Mexico and the mixed shrub areas of salt bush on the Shortgrass Steppe LTER site in Colorado.

“The declines in abundance that we observed and the sensitivity of mammals to climatic variables were highly dependent on the ecosystem and location that we studied,” said Rudgers. “Thus, sensitivity to climate change was not at all consistent across a species’ range. In fact, the identities of winning and losing species differed between ecosystems for 70 percent of the taxa. This means that we need to take the local environment into consideration when making predictions about species vulnerabilities. “


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Climate models can predict decadal precipitation v

image: Ensemble mean forecast anomalies averaged over forecast years 2 to 9 for summer precipitation over the Inner Tibetan Plateau. Red line: retrospectives; Blue line: near real-time predictions; Black line: observations. Shadows represent uncertainty.
seen Following

Credit: HU Shuai

Summer precipitation on the Tibetan Plateau is highly predictable over multi-year timescales in large ensemble forecasts, according to a research team led by ZHOU Tianjun of the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences.

The study, published in Scientists progress June 9, shows that the predictable summer rainfall signal in the Tibetan Plateau hinterland is significantly underestimated in advanced decadal forecast models.

The predictable signal is so weak that it can be masked by unpredictable noise. “The predictable signal that is too weak comes from the low signal-to-noise ratios in the models compared to the real world,” said ZHOU, corresponding author of the study. “This phenomenon is kind of a deficiency in climate models, but it also prompts us to once again recognize the decadal predictability of prediction models.”

ZHOU is Principal Investigator at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics at IAP. He is also a professor at the University of the Chinese Academy of Sciences.

ZHOU and his team used large assemblies from the Sixth Coupled Model Intercomparison Project (CMIP6) of the Decadal Climate Prediction Project (DCPP), an archive of comprehensive decadal prediction experiments based on various climate models, to eliminate stochastic noise. unpredictable and extract the predictable signal. summer rainfall in the Tibetan plateau.

The researchers produced realistic predictions through a post-processing variance adjustment procedure, indicating that the Tibetan Plateau’s summer precipitation is highly predictable over ten-year time scales.

The Tibetan Plateau has the most glaciers outside of the Arctic and Antarctic. Melt water supplies more than 10 major rivers, including the Yangtze River, the Yellow River and the Ganges. “Our results mean a lot for the management of water resources for about 40% of the world’s population,” ZHOU said.

Based on real-time forecasts, the researchers revealed that the Tibetan Plateau hinterland will become wetter, with a 12.8% increase in rainfall for the period 2020-2027 compared to 1986-2005.

“The government and scientists have recognized the urgent need for effective short-term climate information (2021-2040), but there are large uncertainties in traditional short-term climate projections based on summer rainfall scenarios on the Tibetan Plateau. due to internal variability. in the climate system, ”ZHOU said. “Our results demonstrate that decadal climate prediction systems can be a valuable tool in overcoming the shortcoming of traditional projection uncertainties based on short-term climate change scenarios on the Tibetan Plateau.”

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