一次西南低涡诱发川南特大暴雨的综合诊断  

Diagnostic Analysis of a Heavy Rainfall in Southern Sichuan of China Induced by Southwest Vortex

作　　者：陶丽[1] 李国平[1] 

机构地区：[1]成都信息工程学院大气科学学院/高原大气与环境四川省重点实验室,成都610225

出　　处：《气象科技进展》2011年第3期45-49,共5页Advances in Meteorological Science and Technology

基　　金：国家自然科学基金(40875023);灾害天气国家重点实验室开放课题(2009LASW-A01)

摘　　要：利用NCEP/NCAR1°×1°格点再分析资料,对2007年7月8─10日发生在川南地区的西南低涡暴雨做了一次较为全面的诊断分析,结果表明:(1)500hPa高度场上小槽与700hPa西南低涡缓慢东移;流场上有低层辐合高层辐散的结构;垂直速度场上维持有较强烈的上升运动;这些都为暴雨的发展和维持提供了有利的条件。(2)对流层低层假相当位温随高度降低,有不稳定能量的存在,易于触发暴雨。(3)湿位涡分析得出,MPV1垂直结构呈正负值叠加的配置是暴雨发生发展的有利形势,强降水落区基本位于MPV1正负值交界的等值线密集带;MPV2的增大可使对流运动和降水加强。Using NCEP data of 1°×1°with 6-hour interval,the evolution of Southwest Vortex(SW)causing heavy rainfall in Southern Sichuan of China during 8-10 July 2007 is comprehensive diagnosis.The results indicate that:(1)On height field,there is a small groove on 500hPa,and 700hPa southwest vortex moving eastward slowly;on flow field;there is a structure of convergence on the low level and divergence on the upper level;on vertical velocity field,there maintains a relatively strong upward motion,they provide a favorable circulation background for the development and maintenance of heavy rainfall.(2)On the lower troposphere,the pseudo-equivalent temperature decreases with height.The existence of an unstable energy can easily trigger heavy rainfall.(3)Moist potential vorticity analysis gives a superposition of the vertical structure of the configuration,both positive and negative,to provide a favorable situation in the development of heavy rainfall.Strong precipitation areas are basically located in the dense band contour of the positive and negative junction of MPV1;the increase of MPV2 is conducive to the intensification of convection and rain.

关 键 词：西南低涡 暴雨 诊断 湿位涡 

分 类 号：P458.121.1[天文地球—大气科学及气象学]