两次西南涡降水的诊断分析

本文对比分析了2009年夏季两场西南涡引发的暴雨天气过程,通过对涡度各个贡献项以及几个热力诊断量的分析认为,促使西南涡发展的主要贡献是大气的辐合,其次是垂直输送,β效应项的贡献是最小的,可以忽略。从几个热力诊断量来看,通常对流有效位能的释放时间都会先于最强降水的出现时间。K指数和总体指数的极值出现时间一般也略早于最强降水的出现时间。对流有效位能和K指数以及总体指数都对降水预报有一定的指示作用。 

Diagnostic Analysis on Two Southwest Vortex Precipitation Process

The paper analyses on two Southwest vortex precipitation process during summer,2009.According to the analysis contribution iterms of the vorticity and thermodynamic diagnositic variable,we think that the main contribution of southwest vortex evolution comes from atmospheric convergence,secondly from vertical transport,the contribution from β-effect iterm is minimum and can be ignored.According to analysis several thermodynamic diagnositic variable,the results show that the release of convective available potential energy(CAPE) is earlier than the occurrence time of maximum rainfall.The onset time of extreme value of K index and Total index is slightly earlier than the occurrence time of maximum rainfall.The convective available potential energy,K index and Total index have a kind of indication meaning for precipitation forecast.