Seasonal precipitation change in the Western North Pacific and East Asia under global warming in two high-resolution AGCMs

Abstract

To estimate seasonal precipitation change over the western North Pacific and East Asia region (WNP-EA), we use high-resolution atmospheric Model (HiRAM) (50 km resolution) to conduct a series of simulations forced by Representative Concentration Pathways 8.5 (RCP8.5) scenario with the fifth phases of the Coupled Model Intercomparison project (CMIP5) ensemble sea surface temperature (SST) changes (RCP_Ens). The sensitivity of future projections to various SST forcing ( $$ {\text{SST}}_{\text{spa}}^{{\prime }} $$ ) is also assessed. We also assess the sensitivity associated with model dependence by comparing with the results of the Meteorological Research Institute-Atmospheric General Circulation Model (MRI-AGCM3.2S) projections. The major findings are: (1) weakened atmospheric circulation in all seasons in RCP_Ens experiment; (2) more precipitation over most of the northern East Asian continent and the northern WNP oceanic region in all seasons; (3) an anomalous anticyclonic circulation (AAC) together with decreased precipitation over the oceanic WNP-EA in the typhoon season; and (4) largest sensitivity to various $$ {\text{SST}}_{\text{spa}}^{{\prime }} $$ in spring comparing with other seasons. The aforementioned changes are similarly seen in both the HiRAM and MRI-AGCM3.2S, suggesting the reliability of our findings. The moisture budget indicates the dominance of dynamic contribution to the reduced precipitation. By contrast, the increased precipitation may be associated with various processes such as enhanced upward motion, increased water vapor or surface evaporation.