Assessment of intraseasonal characteristics of precipitation over East Asia in the GRIST model summer climate hindcast

Based on the seasonal climate hindcast experiment of the Global-to-Regional Integrated forecast SysTem (GRIST) model, the simulated climate features of East Asian summer precipitation are analyzed with emphasis on the intraseasonal variation. Compared with the China Merged hourly Precipitation Analysis (CMPA) grid fusion analysis dataset, the Global Precipitation Measurement (GPM) satellite dataset and results of two global climate models, i.e., the Community Atmosphere Model version 5 (CAM5) and the SuperParameterized CAM5 (SPCAM5), this study evaluates the simulation results and explores the inter-model differences. Results show that the GRIST can better simulate seasonal variation and evolution of precipitation over the Northwest Pacific Ocean and eastern China, but the magnitude of precipitation variation and rainfall amount are higher than the observed values. It is shown that precipitation evolution closely corresponds to daily mean vertical variations of hourly apparent heat source (Q₁) and apparent moisture sink (Q₂) and large-scale vertical velocity. The model can accurately reproduce the location and northward progression of rain belt and the subtropical high ridge line, and overall can capture the northward propagation of the Intrasesonal Oscillation (ISO). However, the intensity and period of the ISO propagation are quite different from the observations possibly due to the long moving path and duration of zonal wind.