1994年中国华南大范围暴雨过程的形成与夏季风活动的研究

A STUDY ON EXTENSIVE HEAVY RAIN PROCESSES IN SOUTH CHINA AND THE SUMMER MONSOON ACTIVITY IN 1994

利用 1 994年夏季 ECMWF逐日两次的格点资料和日本的 TBB资料 ,结合这一年华南地区 6,7月的站点降水资料 ,诊断分析了 1 994年夏季风 (主要为南海季风 )活动、华南地区的两次特大暴雨过程以及两者之间的关系。结果发现 :这一年的夏季风十分活跃 ,南海夏季风与表征对流活动的 TBB低值带以低频振荡的形式 (周期约为 30～ 60 d)传播到暴雨区 ,与暴雨的发生有着密切的联系 ,强暴雨过程对应着季风的脉动或加强期 ;强劲的季风气流向暴雨区输送水汽 ,其中以南海地区的水汽输送为主 ;两次暴雨过程发生在不同的环流形势下 ,但是都位于较大的水汽辐合和对流不稳定区。

By using twice a day grid data of ECMWF and the TBB data of Japan GMS, together with the daily precipitation data over stations in South China during June and July, 1994, situations of two successive heavy rain processes in South China 、activity of summer monsoon ( mainly the South China Sea monsoon ) and the possible relationships between them are analyzed in this paper. We have found that the summer monsoon in 1994 is active, summer monsoon (especially the South China Sea summer monsoon) as well as the low value area of TBB, is related closely with the heavy rain processes with low frequency oscillation mode (with 30~60 day period). Heavy rain process always corresponds to a strong impulse or strong of monsoon. Strong monsoon flows bring moisture to South China and the major moisture source comes from South China Sea. Although the two heavy rain processes occurred under different conditions, both of them took place in the maximum moisture convergence and convective unstable regions.