一次东北冷涡不同阶段强对流天气特征对比分析

摘要

利用NCAR/NCEP再分析（1°×1°）资料，区域自动站观测、FY-2D/2E卫星观测和GPS/MET水汽监测等资料，对2012年6月7-18日长春地区发生在同一东北冷涡系统不同演变阶段的3次强对流天气过程进行对比诊断分析。结果表明：在冷涡形成期，高低空急流耦合产生的次级环流上升支，触发锋前不稳定能量释放，导致中β尺度孤立深厚湿对流系统出现；在冷涡发展期，对流层高层干冷空气向对流层中下层侵入，形成高空露点锋，触发有组织的中α尺度对流系统；在冷涡消亡期，低涡减弱为高空槽并快速东移，其后部冷空气置于低层大范围暖湿空气之上，地面中尺度辐合触发不稳定能量释放，形成中β尺度对流系统。%Using the NCEP/NCAR reanalysis data with 1 °×1 °spatial resolution,meteorological data from regional automatic weather stations (AWS),FY-2D/2E satellite image and GPS/MET data,three severe convective weath-er events in different stages of Northeast China cold vortex on June 7 to 18,2012 over Changchu area were diag-nosed and compared.The results show that during the forming stage of Northeast China cold vortex,an isolated-deep-moist convection of meso-β-scale is triggered by the ascending branch of secondary circulation induced by coupled high/low jets.During the developing stage of Northeast China cold vortex,a convective system of meso-α-scale is triggered by invasion of dry-cold air from upper to middle and lower troposphere,so forms an upper dew point front at the same time.During the weakening stage of Northeast China cold vortex,a convective system of meso-β-scale is formed by the weakening of Northeast China cold vortex to an upper trough moving eastward, whose rear part is cold air above the large range of low-level warm and moist air,and surface meso-scale conver-ges in the same time.