攀枝花市一次持续性暴雨的中尺度特征分析

Analysis of Mesoscale Characteristics of a Persistent Rainstorm in Panzhihua

利用常规观测资料、自动站雨量站资料、FY-2E逐时云顶亮温TBB资料、雷达资料及NCEP/NCAR 1°×1°再分析格点资料,对2016年7月5—6日四川省内攀枝花市暴雨过程进行分析。结果表明,此次过程是在青藏高原低涡大尺度天气系统的背景条件下,第1阶段强降水是涡旋云系气旋性旋转南下时不断生消的中尺度对流系统直接造成的,中尺度雨团是暴雨的主要表现特征;第2阶段是在低涡切变东南移的过程中,该市低层辐合明显加强,触发了MCS的发生发展。过程强度大,持续时间短,有典型的中尺度特征。降水出现在MCS中部冷云区及梯度大值区。地形的强迫抬升,对此次过程也有重要作用。

Based on the conventional observation data,precipitation data from automatic stations,FY-2E cloud top temperature TBB data, radar data and NCEP/NCAR1°×1°reanalysis grid data ,the analysis of the rainstorm process in Panzhihua from July 5^th-6^th, 2016 was made. The results showed that the first stage of heavy rainfall was the direct result of mesoscale convective system, which was generated when the cyclonic rotation of the vortex cloud was southward, under the background of the large scale weather system of low vortex on the Tibetan Plateau.Mesoseale rain mass was the main characteristic of heavy rain. The second stage was in the process of low vortex shear southeastward shift, the convergence of low-level significantly enhanced, triggering the occurrence and development of MCS. The process was characterized by large intensity, short duration and typical mesoscale characteristics. Precipitation occurred in the middle cold region and the gradient region of MCS. The forced uplift of the terrain had an important role in this process.