Abstract:

Based on the meteorological observation data of 735 stations in the Yangtze River Basin from June to July during 2016-2020, NCEP/NCAR reanalysis data and basin rain information, the regional characteristics, the weather system and causes of main rainstorm processes in the Yangtze River Basin were discussed preliminarily. The results are as follows: (1) The precipitation from June to July during 2016-2020 was mainly affected by the Meiyu front caused by the strengthened west Pacific subtropical high and the eastward movement of the upper low trough in the middle and high troposphere over the Yangtze River Basin. The main influencing systems in the middle and low layers were shear line, vortex and typhoon inverted trough. Half of the precipitation processes in the boundary layer occurred in the warm region or influenced by the static front. (2) The main weather patterns affecting rainstorm processes in the Yangtze River Basin were divided into zonal circulation type, the type between two highs (western Pacific subtropical high and south Asian high), meridional type and easterly flow type. (3) The precipitation difference in the Yangtze River Basin had a good correlation with the subtropical high ridge line location, the northward push process of summer monsoon and the short-term strong precipitation area.

Key words: the Yangtze River Basin, rainstorm, western Pacific subtropical high

摘要：

利用2016—2020年6—7月长江流域735站气象观测资料、NCEP/NCAR再分析资料及雨情信息对长江流域主要暴雨过程的区域性特征、天气系统及成因进行了初步探讨。结果表明:(1)2016—2020年6—7月长江流域降水过程对流层中高层主要受加强西伸的西太平洋副热带高压及高空低槽东移带来的梅雨锋影响,中低层主要影响系统是切变线、低涡、台风倒槽,边界层有一半的降水过程发生在暖区或受静止锋影响;(2)影响长江流域暴雨过程的主要天气形势分为纬向环流型、两高(西太平洋副热带高压与南亚高压)之间型、经向型和偏东气流型;(3)长江流域降水差异同副高脊线位置和夏季风北推进程以及短时强降水落区有很好的相关性。

关键词: 长江流域, 暴雨, 西太平洋副热带高压