Spring Persistent Rainfall in a Grid-Point and a Spectral Atmospheric General Circulation Models

Abstract

Capabilities of the Grid-point Atmospheric Model of Institute of Atmospheric Physics/National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (IAP/LASG; GAMIL) and the Spectral Atmospheric General Circulation Model of IAP/LASG (SAMIL) in simulating the Spring Persistent Rainfall (SPR) in East Asia are evaluated by the Global Precipitation Climatology Project (GPCP). Similar to that observed in the Coupled Model Intercomparison Project Phases 3 and 5 (CMIP3/CMIP5) ensembles, rainfall amount in both GAMIL and SAMIL are slightly overestimated over the SPR domain and are underestimated over the SPR center. For the spatial structure, the northeast-southwest tilted rain belt could not be effectively reproduced by GAMIL, and the main rain belt shifts to the north of its normal position in SAMIL. According to the Taylor diagram, SAMIL generally shows better performances in simulating the SPR pattern. Similar to other atmospheric general circulation models (AGCMs) employed in CMIP3/CMIP5, the thermal contrast between East Asia and the South China Sea is overestimated in SAMIL and GAMIL. The overestimated meridional thermal contrast intensifies the southerly water vapor supply and favors the northward shifting of main rain belt.