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Spatial variations of effective moisture in the western United States
Author(s) -
Shinker Jacqueline J.,
Bartlein Patrick J.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl041387
Subject(s) - evapotranspiration , precipitation , environmental science , climatology , spatial ecology , mesoscale meteorology , arid , water cycle , water content , monsoon , spatial variability , moisture , common spatial pattern , atmospheric sciences , physical geography , geography , geology , meteorology , ecology , statistics , mathematics , paleontology , geotechnical engineering , biology
Spatial patterns of actual evapotranspiration (AE), potential evapotranspiration (PE), and their ratio (AE/PE) in the western United States are examined to describe the annual cycle of moisture availability. Long‐term (1971–2000) averages of observed temperature and precipitation, and sunshine data were used to calculate AE and PE. A cluster analysis identifies regions with similar annual cycles of AE/PE. We identify three different spatial scales of variability in AE/PE: (1) broadscale patterns reflect the trade‐off between winter‐dominated precipitation of the Pacific Northwest and summer‐dominated precipitation east of the Rocky Mountains, and the south‐to‐north decrease in PE related to latitudinal variations in net radiation; (2) mesoscale patterns show the influence of regional‐scale features (e.g., the North American Monsoon); and (3) local‐scale patterns are related to topography. Understanding the scales of effective‐moisture variations is valuable from the perspective of terrestrial ecosystems and water resources management in the mostly arid western United States.