2022年广西最强“龙舟水”气候成因分析

Analysis on the cause of the strongest dragon-boat precipitation in Guangxi in 2022

基于广西91个国家地面气象观测站降水数据和ERA5逐日再分析资料,分析2022年5月21日至6月21日广西“龙舟水”过程的天气气候成因。结果表明:(1)“龙舟水”期间冷空气南下活跃,西太平洋副热带高压位置偏西,南支槽伸至孟加拉湾,水汽条件充沛,冷暖空气交汇导致锋面降水频繁。(2)南海夏季风提前爆发,前期偏强后期减弱,利于雨带滞留广西。(3)200hPa西风急流偏强位置偏南,利于上升运动的维持和加强。(4)基于结构化自组织神经网络聚类的延伸期降水过程预测模型,较好预测出“龙舟水”期间暴雨过程的空间类型和出现时段。

Based on the observation data of daily precipitation of Guangxi national ground meteorological observatories and the ERA5 reanalysis data,the cause of the strongest dragon-boat precipitation in Guangxi from May 21 to June 21,2022,was studied.The results show that the location of the Western Pacific subtropical high is westward and the southern branch trough extends to the Bay of Bengal with abundant warm moisture northward transporting,converged with the active cold air from the north,leading to frequent frontal precipitation.The South China Sea summer monsoon onsets early,which is stronger in the early stage and weakens in the later stage,resulting in the maintenance of the rain belt in Guangxi.The central intensity and location of the upperlevel westerly jet of the 200hPa are stronger and more southerly,which is conducive to the maintenance and strengthening of the upward movement.The extended range precipitation forecasting model based on the structural Self-organizing neural network clustering can well predict the spatial type and occurrence time of heavy rainfall processes during the dragon-boat precipitation rainy season in 2022.