一次暖区暴雨天气过程分析

Analysis of a Rainstorm Weather Process in Warm Area

利用FNL 1°×1°再分析资料、FY-2F卫星TBB资料及常规气象观测资料,对2019年5月24—26日发生在贵州的1次连续性暴雨天气过程进行分析。结果表明:此次连续性暴雨过程地面维持热低压影响,无冷空气影响,是典型的暖区暴雨;高空槽和中低层切变线为暴雨的产生提供了天气尺度背景,地面辐合线是触发对流的重要因子;暴雨发生前大气呈现动力和热力不稳定的结构特征;24日夜间地面辐合线在贵州中部地区稳定维持,触发中β尺度对流单体生成,并发展形成中α尺度系统,对流发展旺盛,伸展高度较高,影响范围广。25日夜间辐合线移动较快,触发的中β尺度对流单体组织性较弱,没有形成中α尺度系统,造成的暴雨局地性强;暴雨与水汽通量散度梯度的大值区、TBB≤-52℃的冷云区和TBB梯度大值区对应较好,TBB≤-65℃的区域有利于大暴雨产生。

Based on FNL 1°×1°reanalysis data,FY-2F TBB data and conventional meteorological observation data,a continuous rainstorm weather process occurred in Guizhou from May 24 to 26,2019 was analyzed.The results showed that the continuous rainstorm process was affected by thermal depression,and had no cold air influence.It was a typical rainstorm in warm area.The upper trough and the shear line of the middle and lower layer provided the synoptic scale background for the rainstorm,and the surface convergence line was an important factor triggering convection.The atmosphere was characterized by dynamic and thermal instability before the rainstorm.During the night of the 24th,the surface convergence line remained stable in central Guizhou,triggering the formation of meso-βscale convective cells and developing into meso-αscale system.The convective development was vigorous,the extension height was high,and the influence area was wide.During the night of the 25th,although the convergence line moved quickly,the organization of the triggered Meso-βScale convective cells was weak,and no meso-αscale system was formed.Therefore,the local rainstorm was strong.In addition,the generation of rainstorm corresponds well to the large value region of water vapor flux divergence gradient,the cold cloud region with TBB≤-52℃and the large value region of TBB gradient,and the region with TBB≤-65℃is conducive to heavy rain.