Uncertainty in Projected Changes in Precipitation Minus Evaporation: Dominant Role of Dynamic Circulation Changes and Weak Role for Thermodynamic Changes

End of century projections from Coupled Model Intercomparison Project (CMIP) models show a decrease in precipitation over subtropical oceans that often extends into surrounding land areas, but with substantial intermodel spread. Changes are controlled by both thermodynamical and dynamical processes, though the importance these processes for regional scales spread is not well understood. The contribution dynamic thermodynamic to model minus evaporation (P ? E) computed 48 CMIP models. dominated essentially everywhere change term, including most regions where changes drive multi-model mean response. dominant role insensitive zonal averaging which removes any influence stationary wave changes, also evident oceanic regions. Relatedly, P E generally unrelated climate sensitivity.