长江中下游一次非典型梅雨锋中尺度暴雨过程的分析研究  

A CASE STUDY ON MESOSCALE HEAVY RAINFALLS WITHOUT MEIYU FRONTAL IN THE RAIN SEASON OF 2001

作　　者：黄永明 倪允琪[2] 

机构地区：[1]南京大学大气科学系,南京210093 [2]中国气象科学院,北京100081

出　　处：《气象学报》2005年第1期100-114,共15页Acta Meteorologica Sinica

基　　金：国家重点基础研究发展规划项目 (G19980 40 90 6 12 )。

摘　　要：利用T10 6物理分析资料、地面与高空加密观测资料和TBB资料对 2 0 0 1年汛期一次非典型的梅雨锋中尺度暴雨过程进行天气学和动力学诊断分析 ,并与 1998年典型的梅雨锋中尺度暴雨过程作一些比较。首先分析了该次暴雨过程的大尺度背景场 ,发现与 1998年典型的梅雨锋形势不同的是 ,5 0 0hPa环流形势表现为贝加尔湖地区是阻塞高压 (阻高 ) ,南海季风涌形式不明显 ,南亚高压位置偏东南 ,高空辐散气流较弱。接着对该暴雨系统的结构进行诊断分析 ,揭示了该非典型梅雨锋中尺度暴雨系统的三维结构 ,包括各物理量如涡度、散度、假相当位温、水汽的通量以及湿位涡等的结构特征。分析表明 ,总体来说 ,该次暴雨过程的强度要比 1998年典型的梅雨锋暴雨要弱 ,相应的各物理量的三维结构与 1998年典型的梅雨锋中尺度暴雨系统的三维结构相比有明显差异。One case of mescoscale heavy rainfalls without background of evident Meiyu front in the raining season of 2001 was analyzed by both the synoptic and dynamic methods, utilizing data of T106, GMS TBB Data and upper & surface observation data from the field experiments in 1998. The analysis results were compared with that of the typical heavy rainfall system with background of Meiyu front. At first the large-scale and synoptic-scale condition of this heavy rainfall process was investigated and revealed that the flow of 500hPa features with a blocking high in the region of Baikal which lasted about three days, there didn't exist distinct strong southerly wind in the region of South China Sea at low level as heavy rainfall in the raining season of 1998 did, the Subtropical High made a eastern and southern excursion compared with the normal position over the same period, and the divergence flows in the high level were weak. Then, the mescoscale structure characters of the intensive convective system were revealed by analyzing observation data, which indicated that this mesoscale intensive convective system without background of evident Meiyu front showed some different 3D characters compared with the 1998 case with evident Meiyu front background, including the variables of vortex, divergence, equivalent potential temperature, moist potential vorticity etc. Finally this case of heavy rainfalls was explored by means of MPV diagnose and some significant conclusion were drawn for further discussion.

关 键 词：暴雨过程 非典型 长江中下游 中尺度暴雨系统 1998年 500hPa 三维结构 诊断分析 2001年 TBB资料 假相当位温 梅雨锋暴雨 物理分析 T106 观测资料 阻塞高压 贝加尔湖 环流形势 南亚高压 结构特征 物理量 动力学 天气学 背景场 

分 类 号：P458.121.1[天文地球—大气科学及气象学] TV87[水利工程—水利水电工程]