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Observed Spatiotemporal Changes in the Mechanisms of Extreme Water Available for Runoff in the Western United States
Author(s) -
Yan Hongxiang,
Sun Ning,
Wigmosta Mark,
Skaggs Richard,
Leung L. Ruby,
Coleman Andre,
Hou Zhangshuan
Publication year - 2019
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 - 10.1029/2018gl080260
Subject(s) - snowmelt , snowpack , environmental science , hydrometeorology , snow , surface runoff , climatology , climate change , water year , hydrology (agriculture) , water resources , atmospheric sciences , precipitation , meteorology , geography , geology , oceanography , ecology , geotechnical engineering , biology
This paper presents the first study to identity, in historical records, regional changes in the mechanisms of extreme water available for runoff ( W ). We used a quality‐controlled Snowpack Telemetry data set (1979–2017) combined with the nonparametric regional Kendall test to examine changes in annual maximum W under four hydrometeorological conditions (melt only/rain‐on‐snow/all melt/all melt plus rainfall) over the mountainous regions of the western United States. Under a warming climate, our analyses indicated significant declining trends in annual maximum W at regional scale under all four conditions. The annual maximum of all melt plus rainfall decreased significantly by 15% in the southwestern United States, while the frequency of rain‐on‐snow events increased significantly by 32% in the northwestern United States. The annual maximum snowmelt only decreased significantly by 21% across the entire western United States. Our results confirmed that interaction between regional humidity and solar radiation with warming temperature helps drive these changes.