Linkage Between Projected Warm Season Precipitation Systems and Thermodynamic and Microphysical Changes Over Eastern China

Abstract

Changes in precipitation systems may affect the local economy, ecosystems, and populations, and further research is necessary to understand their drivers under global warming. In this study, we use the Weather Research and Forecasting model at a convection-permitting (CP, 4 km grid spacing) scale to comprehensively understand the warm season (May–October) precipitation system changes over eastern China. The CP simulations include a historical run (HIST, 1998–2007) forced by ERA-interim and the three pseudo-global warming (PGW) simulations for climate change projection forced by ERA-interim added on monthly mean and ensemble mean climate perturbations from CMIP5 under RCP2.6, RCP4.5, and RCP8.5 emission scenarios. In a warmer climate, the frequency of weak precipitation systems decreases, whereas the frequency and intensity of heavy precipitation systems increase. This shift is primarily due to the higher wet bulb temperature in the warm sector. Additionally, the lower low-level relative humidity, fewer low-level liquid hydrometeors, and increased maximum convective inhibition (MCIN) in a warmer environment suppress the occurrence of weak precipitation systems. Meanwhile, more frequent large values of maximum convective available potential energy and MCIN contribute to more upper-level solid hydrometeors and deeper warm cloud layer, leading to the increased frequency and intensity of heavy precipitation systems in the future warmer climate.