Dynamical Downscaling Simulation and Projection of Extreme Precipitation over East China

Based on the Weather Research and Forecasting (WRF) model driven by the global model IPSL-CM5A-LR results that are included in the model output archive of the Coupled Model Intercomparison Project Phase 5, this study has assessed the model ability for simulating extreme precipitation indices and analyzed possible future changes in the mid-21st century (2041-2060) under the RCP8.5 scenario over East China. Results indicate that WRF performs well in the simulation of extreme precipitation indices. Compared with IPSL-CM5A-LR model, WRF model can better reproduce the spatial distribution and annual cycle of precipitation over East China and the sub-regions. In particular, the simulation of regional features is improved in WRF and the problem in global model to overestimate light precipitation has been overcome. Prediction results show that East China will experience an obvious trend of extremeness on precipitation. WRF simulation results show that indices of annual total wet-day precipitation (PRCPTOT), number of heavy precipitation days (R10mm), and simple daily intensity index (SDⅡ) indices in most regions of East China will increase by more than 20%, the increases of extreme wet days (R95d) and max 5-d precipitation (Rx5day) indices in the northern part of East China will be more than 50% and 35%, and consecutive dry days (CDD) overall will increased in East China. Model grids with significant changes are mainly located in areas with large increases. There will be an extremalization in precipitation with increases in both strong precipitation and drought events, and the degree of extremalization is stronger in the north than in the south of East China.