“05.6”广东致洪暴雨过程的500hPa环流场及低频特征  

500-hPa Circulation Pattern and the Low Frequency Oscillation Characteristics of the "05.6" Flood Inducing Rainstorm

作　　者：纪忠萍[1] 方一川[1] 梁健[1] 梁玉琼[1] 

机构地区：[1]广州中心气象台,广东广州510080

出　　处：《广东气象》2006年第2期15-18,共4页Guangdong Meteorology

基　　金：广东省气象局立项课题:"广东省中期灾害性天气过程的预报研究"

摘　　要：分析2005年6月15～25日广东出现的连续暴雨过程及结束期的500 hPa候平均环流场,并对4～9月暴雨中心区域的降水低频振荡特征进行了分析.结果表明：连续暴雨期欧亚中高纬度维持稳定的两槽一脊形势;中低纬度非洲与西太平洋副热带高压强大,西太平洋副高西伸到广东沿海,青藏高原为稳定的高压脊,高原下游为西风槽活动区,使冷空气沿着高原频繁扩散南下,并与西太平洋副高边缘的暖湿气流相遇,产生连续的暴雨过程.当巴尔喀什湖-贝加尔湖的高压脊东移而转为宽槽区,青藏高原高压脊减弱消失,高原以东为平直的西风环流,我国东北到日本为高压脊控制时,西北太平洋副热带高压加强北抬,华南降水减弱,连续暴雨过程结束.小波分析表明,连续暴雨期存在准20 d的周期振荡.This paper investigates the pentad mean atmospheric circulation fields at 500 hPa during the period from June 15,2005 to June 25, 2005 and the pentad following. The low frequency oscillation characteristics of raincoastal line of Guangdong Province, and a steady high ridge occupied Qinghai - Tibet Plateau. Westerly trough frequently affected downstream areas of the Plateau, driving cold air southward to collide with the warm and humid air stream along the edge of west Pacific subtropical high, resulting in a continuous torrential rain. Then situations began to change ： the high pressure ridge over the Balkhash Lake and Baikal Lake was replaced by a wide trough when it moved eastward; Qinghai -Tibet plateau high pressure ridge weakened and disappeared; westerly wind prevailed over the east of the plateau ; and high pressure ridge began to occupied the areas from Northern China to Japan. With northwest Pacific subtropical high intensifying and shifting northward, South China rainfall weakened and the continuous torrential rain came to an end. An quasi - 20 - day oscillation can be found during the continuous torrential rain by wavelet analysis.

关 键 词：天气学 致洪暴雨 环流场 低频振荡 广东 

分 类 号：P426.6[天文地球—大气科学及气象学]