| 摘要: |
| 该文利用常规气象观测资料、NCEP再分析资料以及卫星和雷达资料，通过对环流背景、云图、雷达以及物理量分析研究，对2020年6月30日贵州特大暴雨过程进行诊断分析，发现此次特大暴雨过程是在高空多短波槽活动、中层弱冷空气的入侵、高空急流和低层切变线长期维持以及西南暖湿气流的持续性输送共同影响下形成的。此次MCC对流云团生成于毕节市威宁县附近，在MCC的初始阶段，对流云团由块状向椭圆形发展，冷云罩面积逐步增大，云顶亮温中心不断降低；成熟阶段由椭圆形逐步扩散为多边形，云顶亮温中心维持在-80 ℃以下；消亡阶段冷云罩面积和云顶亮温绝对值迅速减小。逐小时短时强降雨站数与冷云盖面积有很好的对应关系，在形成、成熟、消亡3个阶段分别呈现逐步上升、明显上升和迅速减小的趋势；最大小时雨量在成熟阶段与最低云顶亮温有较好的对应关系。此次特大暴雨过程中强回波基本集中在4 km以下，中低层越靠近地面回波越强，强回波接地，质心低。初始阶段强回波强度强，移速快，但生命史短，呈现单峰值分布；成熟阶段的强回波范围大，持续时间长，移速慢，呈现多峰值分布。TI≥44 ℃的大值区长期维持，低层的暖平流和上升气流以及正涡度辐合，配合高层的冷平流和下沉气流以及负涡度辐散，为此次特大暴雨过程提供了有利的能量和动力条件。 |
| 关键词: MCC；特大暴雨；副热带高压；切变线 |
| DOI： |
| 投稿时间：2021-04-29 |
| 基金项目:贵州省气象局重要业务科研项目（黔气标合ZY[2020] 04号）：“FAST”关键区域人工防雹作业指标研究 |
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| Diagnostic Analysis of Extremely Rainstorm Caused by MCC in Guizhou Province in 2020 |
| WANG Xingju,LUO Xiping,WANG Minghuan,ZHOU Wenyu,MENG Jun,HU Qiuhong |
| (Anshun Meteorological Bureau of Guizhou province, Anshun 561000 , China;Weather Modification Office of Guizhou Province, Guiyang 550081 , China;Institute of Heavy Rain.CMA.Wuhan, Wuhan 430205 ,China;Guizhou Meteorological Observatory, Guiyang 550002 , China) |
| Abstract: |
| In this paper, the conventional meteorological observation data, NCEP reanalysis data, satellite and radar data are used to diagnose and analyze the extremely rainstorm process in Guizhou on June 30, 2020 through the analysis of circulation background, satellite cloud picture, meteorological radar and physical quantity. It is found that the extremely rainfall is caused by the multi-short-wave trough activity in the upper air, the invasion of weak cold air in the middle air, the long-term maintenance of the upper jet and the lower shear line, and the continuous transport of the southwest warm and humid air. The MCC convective cloud cluster was formed near Weining County of Bijie City. In the initial stage of MCC, the convective cloud cluster develops from blocky to elliptic, the cold cloud cover area increases gradually, and the center of TBB of the cloud top decreases continuously. The convective cloud pattern in the mature stage gradually diffuses from ellipse to polygon, and the center of TBB of the cloud top is maintained below -80 ℃. The area of the cold cloud cover and the absolute value of the cloud-top TBB decrease rapidly during the extinction stage. There is a good correspondence between the number of short-term heavy rainfall stations and the cold cloud cover area, which showed a trend of gradual increase, obvious increase and rapid decrease respectively in the three stages of formation, maturity and extinction. There is a good correspondence between the maximum hourly rainfall and the lowest cloud-top TBB at the mature stage. In this extremely rainfall process, the strong echo is basically concentrated below 4 km. The closer the echo is to the ground, the stronger it gets. The strong echo is grounded, and has a low center of mass. In the initial stage, the strong echo has strong strength and fast moving speed, but it has a short life and presents a single peak distribution. In the mature stage, the strong echo has large range, long duration, slow moving speed and multi-peak distribution. The TI large value region greater than or equal to 44 is maintained for a long time, the convergence of warm advection and updrafts and positive vorticity of the lower layer, coupled with the cold advection and downdraft of the upper layer and the divergence of negative vorticity, provides favorable energy and dynamic conditions for this extremely rainfall process. |
| Key words: MCC；extremely rainfall； subtropical high； shear line |
