重庆市北碚区两次暴雨天气过程对比分析

Comparative Analysis of Two Heavy Rain Weather Processes in Beibei District of Chongqing City

摘要: 本文应用了ECMWF-ERA5的逐时再分析数据对重庆市北碚区2019年7月31日和9月9日两次暴雨天气过程进行了比较和分析，结果表明：从等压面图的高空环流形势来看，影响两个过程的降水系统均是高空低涡，北碚地区均受偏南气流的控制。从大尺度分析9.9过程系统配置强度强于7.31过程，7.31过程其纬度系统稳定少动。从影响暴雨的物理量场分析来看，7.31过程最大负垂直速度中心与9.9过程最大负垂直速度中心出现的时间和高度均有所差异。从涡度、散度和水汽条件分析，9.9过程辐合上升和正涡度平流条件优于7.31过程且9.9过程上空水汽更为充沛。从两次天气过程中影响降水的系统综合来看，7.31过程降水影响范围小，更多的是局部性降水，由于低值系统稳定，因此降水持续时间较长。而9.9过程能量和水汽条件均优于7.31过程，降水强度更强，影响范围更广。

Abstract: This paper uses the time-to-hour reanalysis data of ECMWF-ERA5 to compare and analyze the two heavy rain weather processes in Beibei District of Chongqing City on July 31 and September 9, 2019. The results show that the upper-air circulation from the isobaric map in terms of the situation, the precipitation systems that affect the two processes are both high-altitude vortexes, and the Beibei area is controlled by the southerly airflow. From the large-scale analysis, the 9.9 process system configuration strength is stronger than the 7.31 process, and the latitude system of the 7.31 process is stable and less moving. From the analysis of the physical quantity field that affects the rainstorm, the time and height of the maximum negative vertical velocity center in the 7.31 process and the maximum negative vertical velocity center in the 9.9 process are different. From the analysis of vorticity, divergence and water vapor conditions, the convergent rise and positive vorticity advection conditions of the 9.9 process are better than those of the 7.31 process and the water vapor over the 9.9 process is more abundant. From the comprehensive point of view of the system that affects precipitation during the two weather processes, the precipitation impact range of the 7.31 process is small, and more local precipitation. Because the low-value system is stable, the precipitation lasts longer. The 9.9 process energy and water vapor conditions are better than the 7.31 process, the precipitation intensity is stronger and the influence range is wider.