TY - JOUR
T1 - Moisture flux convergence in regional and global climate models
T2 - Implications for droughts in the southwestern United States under climate change
AU - Gao, Yanhong
AU - Leung, L. Ruby
AU - Salathé, Eric P.
AU - Dominguez, Francina
AU - Nijssen, Bart
AU - Lettenmaier, Dennis P.
PY - 2012/5/1
Y1 - 2012/5/1
N2 - The water cycle of the southwestern United States (SW) is dominated by winter storms that maintain a positive annual net precipitation. Analysis of the control and future climate from four pairs of regional and global climate models (RCMs and GCMs) shows that the RCMs simulate a higher fraction of transient eddy moisture fluxes because the hydrodynamic instabilities associated with flow over complex terrain are better resolved. Under global warming, this enables the RCMs to capture the response of transient eddies to increased atmospheric stability that allows more moisture to converge on the windward side of the mountains by blocking. As a result, RCMs simulate enhanced transient eddy moisture convergence in the SW compared to GCMs, although both robustly simulate drying due to enhanced moisture divergence by the divergent mean flow in a warmer climate. This enhanced convergence leads to reduced susceptibility to hydrological change in the RCMs compared to GCMs.
AB - The water cycle of the southwestern United States (SW) is dominated by winter storms that maintain a positive annual net precipitation. Analysis of the control and future climate from four pairs of regional and global climate models (RCMs and GCMs) shows that the RCMs simulate a higher fraction of transient eddy moisture fluxes because the hydrodynamic instabilities associated with flow over complex terrain are better resolved. Under global warming, this enables the RCMs to capture the response of transient eddies to increased atmospheric stability that allows more moisture to converge on the windward side of the mountains by blocking. As a result, RCMs simulate enhanced transient eddy moisture convergence in the SW compared to GCMs, although both robustly simulate drying due to enhanced moisture divergence by the divergent mean flow in a warmer climate. This enhanced convergence leads to reduced susceptibility to hydrological change in the RCMs compared to GCMs.
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U2 - 10.1029/2012GL051560
DO - 10.1029/2012GL051560
M3 - Article
AN - SCOPUS:84861117519
SN - 0094-8276
VL - 39
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 9
M1 - L09711
ER -