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

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.

REFERENCE

• Ting, M., R. Seager, C. Li, H. Liu, and N. Henderson, 2018: Mechanism of Future Spring Drying in the Southwest U.S. in CMIP5 Models. J. Climate.
  doi:10.1175/JCLI-D-17-0574.1, in press.