Robust Spring Drying in the Southwestern U.S. and Seasonal Migration of Wet/Dry Patterns in a Warmer Climate
This study compares climate simulations over North America produced by a regional climate model with the driving global climate simulations as well as a multimodel ensemble of global climate simulations to investigate robust changes in water availability (precipitation (P)-evapotranspiration (E)). A robust spring-drying signal across multiple models is identified in the Southwest that results from a decrease in P and an increase in E in the future. In the boreal winter and summer, the prominent changes in P-E are associated with a north-south dipole pattern, while in spring, the prominent changes in P-E appear as an east-west dipole pattern. The progression of the north-south and east-west dipole patterns through the seasons manifests clearly as a seasonal "clockwise" migration of wet/dry patterns, which is a robust feature of water availability changes in North America consistent across regional and global climate simulations.