2008年华南前汛期连续性暴雨过程成因探析  

Analysis on the Pre-flood Season Sustained Rain Process of Southern China in 2008

作　　者：王明洁[1] 张小丽[1] 陈元昭 朱小雅 

机构地区：[1]广东深圳市国家气候观象台,广东深圳518040

出　　处：《安徽农业科学》2009年第36期18101-18103,18144,共4页Journal of Anhui Agricultural Sciences

摘　　要：利用NCEP/NCAR 1970～2008年5～6月逐日平均高度、温度、湿度、风场、海平面气压等再分析资料,分析2008年华南前汛期连续性暴雨过程的大气环流特征,并探讨了连续性暴雨过程的成因。结果表明,连续性暴雨过程期间大气环流出现异常变化,中高纬度西亚脊稳定、东亚槽偏深、东亚上空西风带经向度偏大、副热带高压偏西、南支槽活跃,有利于华南前汛期暴雨形势的出现;极涡的异常变化使得影响我国的冷空气活跃,有利于极地冷空气不断分裂南下;华南沿海附近存在异常的对流增强活动,使得华南沿海暖湿气流活跃,有利于强对流天气的发生;孟加拉湾的对流增加与南海夏季风的活动密切相关,连续性暴雨期间强降水过程与夏季风的增强相对应;在连续性暴雨期间,我国东部特别是华南沿海地区水汽输送通量明显偏多,低层为水汽异常辐合,为连续性暴雨过程提供了充足的水汽;南亚高压的异常变化为2008年前汛期华南暴雨过程的发生提供了动力条件,是前汛期暴雨过程频繁的动力机制。By using NCEP/NCAR reanalysis data of daily mean height,temperature,humidity,wind,sea level pressure in May and June from 1970 to 2008,the atmospheric circulation characteristics and the causes for the sustained rain process of Southern China in 2008 were studied.The results showed that the abnormities of atmosphere circulation,stability of high-latitude west ridge,deep trough in East Asia,subtropical westing,active south branch benefited the occurrence of pre-flood season rain.The anomaly changes of polar vortex made the cold air flourished which promoted cold air toward southern.The warn and wet airflow which influenced by the convective anomaly over the Southern China promoted convective weather.The convective anomaly on Bay of Bengal and the heavy rain associated with the development of South Sea summer monsoon.The abnormal moisture transport on East China especially in Southern China and divergence occurred which provided abundant vapor for the sustained rain process.The anomaly of South Asian High provided dynamical condition for the pre-flood season sustained rain process.

关 键 词：天气学 前汛期 连续性暴雨 环流异常 

分 类 号：S161.6[农业科学—农业气象学]