Evaluation of Precipitation Simulated by the Atmospheric Global Model MRI-AGCM3.2.

The performance of the Meteorological Research Institute-Atmospheric General Circulation model version 3.2 (MRI-AGCM3.2) in simulating precipitation is compared with that of global atmospheric models registered to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The Atmospheric Model Intercomparison Project (AMIP) experiments simulated by 36 Atmospheric General Circulation Model (AGCM)s and the High Resolution Model Intercomparison Project (HighResMIP) highresSST-present experiments simulated by 23 AGCMs were analyzed. Simulations by MRI-AGCM3.2S (20-km grid size) and MRI-AGCM3.2H (60-km grid size) are included as a part of the HighResMIP highresSST-present experiments. MRI-AGCM3.2S has the highest horizontal resolution of all 59 AGCMs. As for the global distribution of seasonal and annual average precipitation, monthly precipitation over East Asia, and the seasonal march of rainy zone over Japan, MRI-AGCM3.2 models perform better than or equal to CMIP6 AMIP AGCMs and HighResMIP AGCMs. HighResMIP AGCMs (average grid size 78 km) perform better than CMIP6 AMIP AGCMs (180 km) in simulating seasonal and annual precipitation over the globe, and summer (June to August) precipitation over East Asia. MRI-AGCM3.2 models perform better than or equal to CMIP6 AMIP AGCMs and HighResMIP AGCMs in simulating extreme precipitation events over the globe. Correlation analysis between grid size and model performance using all 59 models revealed that higher horizontal resolution models are better than lower resolution models in simulating the global distribution of seasonal and annual precipitation and the global distribution of intense precipitation, and the local distribution of summer precipitation over East Asia. [ABSTRACT FROM AUTHOR]