2010年5—6月南方持续性暴雨的成因分析

The Causation Analysis of Persistent Heavy Rain over Southern China During May—June 2010

2010年5月5日至6月27日我国江南至华南地区出现11次持续性暴雨过程,引起华南和江南洪涝灾害。利用NCEP日再分析资料,初步分析了持续性暴雨的成因。结果表明,2010年5—6月11次持续降水期间乌拉尔山阻塞高压和贝加尔湖大槽较常年偏强且稳定维持,副热带高压异常偏强,位置稳定偏南,为华南持续暴雨天气建立了有利的稳定大尺度环流背景;强盛的季风气流不断地将暖湿水汽输送至江南至华南地区并在那里和来自中高纬度的干冷空气汇合;高原上多低值系统东传是暴雨发生发展过程中重要的中尺度对流系统。中纬度相当位温锋面南侧不稳定大气层结属性气流造成强烈的上升运动,并与强烈的水汽通量辐合为持续性致洪暴雨提供了非常有利的动力热力条件。

The eleven persistent heavy rains occurred over southern China during 5 May to 27 June in 2010. By using NCEP/NCAR daily reanalysis data,the causes for persistent heavy rains are analyzed.The results show that the Ural blocking high,Baikal low trough and the West Pacific subtropical high are stronger than the normal,and they are successively and stably maintained.The strong southwest air successively meets with the dry cold air from middle and high latituded in southern China.The low vortex which continued to move eastward is the important heavy-rain-producing mesosacle convective system.The strong ascending flow resulting from the instable warm air and the strong vapor flux convergence are the favorable heavy-rain-producing conditions.