Tuesday, March 12, 2013

Long-Term Droughts in Southwestern N. America


Monsoon Failure Key to Long Droughts in Southwest



Long-term droughts in the Southwestern North America often mean failure of both summer and winter rains, according to new tree-ring research from a University of Arizona-led team.The finding contradicts the commonly held belief that a dry winter rainy season is generally followed by a wet monsoon season, and vice versa.
The new research shows that for the severe, multi-decadal droughts that occurred from 1539 to 2008, generally both winter and summer rains were sparse year after year.

"One of the big questions in drought studies is what prompts droughts to go on and on," said lead author Daniel Griffin, a doctoral candidate in the UA School of Geography and Development. "This gives us some indication that the monsoon and its failure is involved in drought persistence in the Southwest."

http://www.sciencedaily.com/releases/2013/03/130311151120.htm

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