2023年6月22—25日广西持续性暴雨成因及数值预报效果分析

Analysis of the causes and numerical forecasting performance of persistent rainstorm in Guangxi during June 22-25,2023

利用常规气象观测资料、ERA5再分析资料和ECMWF、CMA模式预报产品,分析2023年6月22—25日广西持续性暴雨过程系统演变特征和物理量特征,评估分析数值模式预报效果。结果表明,稳定的大气环流背景为持续性暴雨提供有利的形势条件,高、中、低层中尺度天气系统相互耦合影响,为暴雨天气过程提供有利的动力条件;深厚的水汽条件和充足的大气不稳定能量为暴雨天气的出现提供有利的大气环境条件,西南季风稳定维持并在夜间加强为暴雨区持续补充水汽和不稳定能量,并且西南风急流和环境动力条件配置的变化特征与降水强度特征变化相一致。预报业务中可以综合利用大尺度数值模式的强降雨落区预报和中尺度数值模式的降雨量级预报结果,对暴雨预报进行综合订正。

Based on the conventional meteorological observations,ERA5 reanalysis data,ECMWF and CMA model forecast products,the characteristics of the evolutions and physical quantities of the persistent rainstorm process in Guangxi during June 22—25,2023 are analyzed,and the prediction performance of the numerical models is assessed and analyzed.The results show that the stable atmospheric circulation background provides favorable conditions for the persistent rainstorm and the coupling effects of the uppermiddle-and lower-level mesoscale weather systems provide favorable dynamical conditions for the rainstorm process.The profound water vapor conditions and sufficient atmospheric unstable energy provide favorable atmospheric conditions for the occurrence of the rainstorm,and the southwesterly monsoon is stably maintained and strengthened at night to continuously replenish the water vapor and unstable energy for the rainstorm area.Besides,the changing characteristics of the configuration of the southwesterly jets and the environmental dynamic conditions are consistent with the variations of the precipitation intensity features.Therefore,the operational forecasting service can comprehensively utilize the prediction of heavy rainfall fallout areas from large-scale numerical models and of rainfall magnitude from mesoscale numerical models to make comprehensive revisions to the rainstorm forecasts.