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U.S. desert areas to become even more arid (OCTOBER 25, 2018 )

Titre : U.S. desert areas to become even more arid

Geologists from the University of Innsbruck study rainfall patterns in the distant past to better understand how deserts in the southwest United States will be impacted by future climate change. (OCTOBER 25, 2018 )

Beneath the Amargosa desert of the southwest United States lies a hidden gem for climate research. The Devils Hole cave system, named after its bottomless depths, provides a window into the vast desert aquifer below. The cave system is home to a peculiar type of calcite deposit. As groundwater slowly passes through the cave, calcite precipitates layer by layer on the rock walls. "These thin layers have been accumulating on the walls for nearly 1 million years," explains Kathleen Wendt from the Quaternary Research Group in the Department of Geology at the University of Innsbruck. "The height of ancient deposits in Devils Hole cave tell us how high the water table was in the past."

Rises and falls in the local water table provide important clues to changes in rainfall patterns in the southwest United States. Most of the rainfall that recharges the desert aquifer comes from winter storms that move east along the Pacific storm track. The position and intensity of these winter storms depend on many factors, including surface ocean temperatures and the strength of pressure systems in the eastern Pacific. Whenever these factors changed dramatically in the past, such as during an ice age, the position of the Pacific storm track shifted in latitude.

Source  : University of Innsbruck

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Page publiée le 29 juin 2021