Robust spring drying in the southwestern U.S. and seasonal migration of wet/dry patterns in a warmer climate

Abstract

AbstractThis 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.