一次引发川东暴雨的西南涡特征分析  

A Case Analysis of Southwest Vortex Causing Heavy Rainfall in Eastern Sichuan

作　　者：屠妮妮[1] 李跃清[1] 

机构地区：[1]中国气象局成都高原气象研究所,四川成都610072

出　　处：《干旱气象》2014年第6期962-971,共10页Journal of Arid Meteorology

基　　金：973项目(2012CB417202);国家自然科学基金(41275051;41275052)共同资助

摘　　要：利用NCEP再分析格点资料、常规观测资料、自动站降水资料、0.1°×0.1°的FY-2E云顶亮温资料,对2013年6月29日至7月1日发生在四川东部的大暴雨过程进行分析,结合涡度收支方程重点分析了引发这次大暴雨的西南涡结构。结果表明:在西南低涡发生发展过程中,对低涡发展起直接作用的是水平辐合辐散项和水平平流项,低涡形成前水平辐合辐散项起主要贡献,低涡形成后水平平流项贡献增大,并在对流层中低层以正贡献为主,扭转项贡献最小,而垂直输送项在低涡形成前期以正贡献为主,低涡减弱阶段以负贡献为主;在西南低涡形成前期,对流层高层有位涡大值区向下传输至中层,中高层正位涡叠加在低层负位涡之上,有利于低层低涡的发展及不稳定能量的存储与释放,是低涡维持发展的重要因素。Based on the NCEP reanalysis data with 1° × 1° spatial resolution,the conventional observation data,the precipitation from the automatic weather stations and the TBB with 0. 1° × 0. 1° spatial resolution from FY- 2E satellite,a heavy rainfall process occurred in eastern Sichuan from 29 June to 1 July,2013 was analyzed,firstly. And then the structure of southwest vortex causing the heavy rainfall was investigated emphatically by using the vorticity budget equation. The results indicated that the horizontal convergence and divergence term as well as horizontal advection term played a direct role in the development of southwest vortex. The horizontal convergence and divergence term was the main contribution to the vortex development before the vortex formed,while the influence of the horizontal advection term increased after its formation,and was mainly positive contribution in the middle and lower troposphere.The influence of the twist term on the vortex development was smallest. The vertical transport term was mainly consisted of positive valucs in earlier stage of the vortex formation while in weakening stage of the vortex it was negative contribution. In earlier stage of the southwest vortex formation,the potential vorticity from the high level troposphere was transported downwards to the middle level troposphere,and led to the development of the low level vortex.

关 键 词：西南涡 暴雨 涡度收支 湿位涡 

分 类 号：P458.121.1[天文地球—大气科学及气象学]