2021年5月深圳一次暴雨天气过程诊断分析

Diagnostic Analysis of a Rainstorm Weather Process in Shenzhen in May 2021

本文采用NCEP再分析资料、地面常规气象观测资料,运用天气学诊断分析方法对深圳市2021年5月31日的一次暴雨天气过程进行分析。结果表明:1) 导致本次暴雨的中尺度天气系统是低层850 hPa切变线,其南侧的西南风带将大量水汽输送至暴雨区,同时暴雨落区、降水量突增发生时间与切边线移动及偏南大风带前端的位置配合较好。2) 本次暴雨水汽来源主要为南海区域和北部湾,水汽辐合带自南向北传播,暴雨发生前深圳上空较强的水汽辐合区,为此次暴雨提供充足的水汽供应。3) 本次暴雨的动力结构表现为低层强辐合,高层强辐散,符合抽吸原理,加强了垂直上升运动强度,因此垂直运动可以作为深圳今后暴雨预报的提前指示量。

Using NCEP reanalysis data and ground conventional meteorological observation data, this paper analyzes a rainstorm weather process in Shenzhen on May 31, 2021 by using synoptic diagnostic analysis method. The results show that: 1) the mesoscale weather system leading to this rainstorm is the low-level 850 hPa shear line. The southwest wind belt on the south side of it transports a large amount of water vapor to the rainstorm area. At the same time, the rainstorm falling area and the occurrence time of sudden increase of precipitation are well matched with the movement of the shear line and the position of the front end of the southerly gale belt. 2) The water vapor source of this rainstorm is mainly from the South China Sea and Beibu Gulf. The water vapor convergence zone spreads from south to north. The strong water vapor convergence area over Shenzhen before the rainstorm provides sufficient water vapor supply for this rainstorm. 3) The dynamic structure of this rainstorm is characterized by strong convergence at the low level and strong divergence at the high level, which conforms to the suction principle and strengthens the intensity of vertical upward movement. Therefore, the vertical movement can be used as an early indicator of Rainstorm Forecast in Shenzhen in the future.