Extreme Southwest U.S. and Northern Mexico Vapor Pressure Deficit Events in CMIP6 Climate Model Projections

Abstract

This study characterizes the most extreme events of vapor pressure deficit (VPD) in CMIP6 SSP5-8.5 projections for nine different climate models in the greater Southwest U.S. and Northern Mexico region. VPD is a strong predictor of wildfire area burned in Southwestern North America. Model base states are in spatial agreement for temperature and moisture to observational studies. Two areas of VPD are present with differing dominant terms in VPD formulation. Individual event extremities also have differing dominant terms. Precipitation hinders the evolution and magnitude of VPD extremities. Maximum yearly VPD takes place prior to maximum yearly solar insolation in all models, just prior to precipitation of the expected North American Monsoon. Among all extreme events, a minimal precipitation signal is present in the period prior.