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IMAGE: Jeffrey pine needles and branches burn inside of the combustion chamber at DRI during a new study that investigated the effects of smoke and heat on water repellency of sand. view more
Credit: Vera Samburova/DRI.
Reno, Nev. (May 25, 2021) - After a wildfire, soils in burned areas often become water repellent, leading to increased erosion and flooding after rainfall events - a phenomenon that many scientists have attributed to smoke and heat-induced changes in soil chemistry. But this post-fire water repellency may also be caused by wildfire smoke in the absence of heat, according to a new paper from the Desert Research Institute (DRI) in Nevada.
published in the journal Frontiers in Water.
“The recent drought in the Pantanal was caused by a meteorological phenomenon we call atmospheric blocking. A high-pressure area prevented the formation of rainclouds throughout the central-western portion of South America. Temperatures were very high and relative humidity very low,”
José Marengo, a researcher at CEMADEN and principal investigator for the study, told
Agência FAPESP.
“Lack of rain combined with high temperatures and very low humidity led to a heightened risk of fire, which extended to agricultural areas as well as natural parts of the biome.”
Deliberate burning of vegetation to clear land for cattle ranching contributed to the spread of wildfires throughout the region, and these were harder to control owing to the long period of drought. “Fires caused on one hand by warmer air and lack of rain in the Pantanal, and on the other by the burning of areas to clear the vegetation for cattle to graze, resulted i
Credit: Jack Williams.
MADISON - A global survey of fossil pollen has discovered that the planet s vegetation is changing at least as quickly today as it did when the last ice sheets retreated around 10,000 years ago. Beginning some 3,000-to-4,000 years ago, Earth s plant communities began changing at an accelerating pace. Today, this pace rivals or exceeds the rapid turnover that took place as plants raced to colonize formerly frozen landscapes and adapt to a global climate that warmed by about 10 degrees Fahrenheit.
The research, published May 20 in
Science, suggests that humanity s dominant influence on ecosystems that is so visible today has its origin in the earliest civilizations and the rise of agriculture, deforestation and other ways our species has influenced the landscape.
Foehns warm, dry, downslope winds descending the lee side of mountain slopes cause hazardous hot weather in parts of Japan. A new University of Tsukuba study presents the first comprehensive climatological analysis of Japan s south foehns on the Toyama Plain. Most foehns were caused by a dynamical mechanism and occurred while an extratropical cyclone was over the Sea of Japan, although some occurred with an anticyclone over Japan, and hazardous high-temperature foehns occurred with typhoons near Japan.
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IMAGE: Droughts, such as the one impacting Devil s Punchbowl on the northern slope of the San Gabriel Mountains in Los Angeles County, have increased in duration and severity over the past. view more
Credit: Amir AghaKouchak / UCI
Irvine, Calif., May 17, 2021 Greenhouse gases and aerosol pollution emitted by human activities are responsible for increases in the frequency, intensity and duration of droughts around the world, according to researchers at the University of California, Irvine.
In a study published recently in
Nature Communications, scientists in UCI s Department of Civil & Environmental Engineering showed that over the past century, the likelihood of stronger and more long-lasting dry spells grew in the Americas, the Mediterranean, western and southern Africa and eastern Asia.