2020年6月广西持续性暴雨的天气气候特征

Synoptic and climatic characteristics of persistent rainstorm in Guangxi in June 2020

2020年5月30日至6月10日广西出现了大范围持续性暴雨天气过程,造成西江流域部分地区发生洪涝及其衍生灾害。基于广西90个气象观测站降水数据和NCEP/NCAR逐日再分析资料,研究了此次持续性暴雨过程的天气气候特征。结果表明:(1)持续性暴雨期间,西太平洋副热带高压异常偏强、偏西,稳定控制在华南及南海地区,青藏高原上不断有高空短波槽东移。广西位于短波槽槽前和西太平洋副热带高压西侧,大量水汽沿短波槽前和南海季风槽槽前的西南气流向广西输送,有利于暴雨天气维持。(2)暴雨期间大气环流的经向度增加,冷空气势力增强。弱冷空气持续南下到达广西北部与暖空气交汇,诱发暴雨发生。(3)高温高湿高能使广西大气变得异常不稳定,为广西持续性暴雨天气产生提供了有利条件。

From May 30 to June 10,2020,a large-scale continuous rainstorm weather process occurred in Guangxi,which caused flooding and its derivative disasters in Xijiang River Basin.Based on the precipitation data of 90 national meteorological stations in Guangxi and NCEP/NCAR daily reanalysis data,this paper studied the climate characteristics of this continuous rainstorm process.The results showed that(1)during the persistent rainstorm,the Western Pacific Subtropical High was abnormally strong and westward,and it was stable in South China and South China Sea region.There was a continuous eastward movement of the upper shortwave trough on the Qinghai Tibet Plateau.Guangxi was located in front of the short wave trough and the west side of the Western Pacific Subtropical High.A large amount of water vapor was transported to Guangxi along the southwest airflow in front of the short wave trough and the South China Sea monsoon trough,which was conducive to the maintenance of rainstorm.(2)During the rainstorm,the meridional degree of atmospheric circulation and the cold air force increased.The weak cold air continued to reach the north of Guangxi and joined the warm air,causing the rainstorm.(3)The high temperature,high humidity and high energy made the atmosphere of Guangxi become abnormal unstable,which provided favorable conditions for the continuous rainstorm.