江西“06.19”强降水天气成因及中尺度特征分析

THE MESO-SCALE CHARACTERISTICS AND GENETIC ANALYSIS OF A HEAVY RAINSTORM IN JIANGXI

利用区域气象观测资料、常规观测资料、雷达和NCEP资料,对2010年6月19日江西创历史大暴雨过程的成因及中尺度特征进行分析。结果表明:此次过程发生在江西典型暴雨形势背景下,具有显著的中尺度特征;强降水落区位于地面中尺度切变线附近,中尺度系统提前或同时于强降水生成;强降水位于低层水汽通量大值中心前端和水汽强辐合的重叠区域,与强上升运动区及θse≥78℃高能舌北侧密集锋区对应;中尺度对流系统(MCS)合并使降水加强,东西向直线排列的MCS不断向东移动造成持续强降水,落区位于TBB低值区和邻低值中心大梯度区;中-β尺度强回波带稳定且具高降水效率,并形成"列车效应";辐合线、逆风区、中气旋和中层冷侵入等促进强降水发生和维持。

Using meso-scale automatic weather station data,conventional observation data,FY-2E satellite data,radar data,and NCEP 10°×10° reanalysis data,the meso-scale characteristics of a heavy rainstorm occurred on 19 June 2010 in Jiangxi were analyzed.The results show that this process presented the obvious meso-scale characteristics under the typical circulation background of Jiangxi rainstorm.The heavy rainfall located in the proximity of the surface meso-scale shear line,where is the front-end of largest lower-level moisture flux region and the overlap region of the strong moisture convergence region.These regions correspond to the strong vertical ascending motion and north side of the high energy tongue with θse 78 ℃.The meso-scale system appeared before or during the heavy rainfall occurrence.The continuously eastward movement of the longitudinal arraying MCS enhances the sustainable heavy rainfall,and the heavy rainfall occurred in the TBB lower-value and large gradient region.The stable meso-β echo presented ＂train effect＂,which induced high efficient precipitation.The convergence line,adverse wind region,meso-cyclone and mid-level cold invasion improved the occurrence and maintenance of heavy precipitation.