副高控制下一次局地致灾强降水天气分析

Analysis of a Local Disaster Causing Heavy Precipitation under the Control of Subtropical High

2021年6月11日江西省上饶市南部出现了一次局地性强降水天气,造成了该地区出现城市内涝、农田被淹、房屋毁损等灾情。此次致强降水天气出现在副高控制的背景下,700 hPa和850 hPa风场较弱,边界层存在弱辐合线,整层湿度条件较好。从雷达探测结果来看,导致灾害性短时强降水的回波主要为团状对流单体,对流云系中心强度强、持续时间长是造成短时强降水的主要原因。从雷达的偏振量特征来看,回波云团主要由高浓度的大水滴组成,ZDR和KDP参数能较好地反映云团内部的雨滴形态和分布特征;CC和HCL产品则由于雷达波束的阻挡,在判定降水粒子相态受到了一定的干扰。

On June 11, 2021, a local heavy rainfall occurred in the south of Shangrao City, Jiangxi Province, resulting in serious losses such as urban waterlogging,farmland flooding, house damage and so on. The disastrous weather occurs under the background of subtropical high control.The wind fields of 700 hPa and 850 hPa are weak, there is a weak convergence line in the boundary layer, and the humidity conditions of the whole layer are very good. From the radar detection results, the echo leading to disastrous short-term heavy precipitation is mainly cluster convective monomer. The strong central intensity and long duration of convective cloud system are the main reasons for short-term heavy precipitation. From the polarization characteristics of radar, the echo cloud cluster is mainly composed of large water droplets with high concentration.ZDR and KDP parameters can better reflect the shape and distribution characteristics of raindrops in the cloud cluster;CC and HCL products are subject to certain interference in determining the phase state of precipitation particles due to the blocking of radar beam.