2017年抚州市一次飑线天气诊断分析

Weather Diagnosis and Analysis of a Squall Line in Fuzhou in 2017

基于常规天气图、地面自动站和多普勒雷达等资料,对2017年6月5日抚州市一次飑线过程的地面气象要素、环流形势以及天气尺度、不稳定能量、雷达回波演变特征等进行分析。分析表明:此次过程在中高纬度“两槽一脊”的环流形势下,中低层西南急流的形成促成了大气对流不稳定,地面辐合线是强对流天气发生的触发机制。飑线过境时温、压、湿等气象要素发生了剧烈变化。飑线形成之前,低层增温、增湿为强对流天气发生累积的不稳定能量起到促进的作用。快速东移的弓形回波带、在回波所经之地易出现雷暴大风天气;径向速度图上大片负的速度区前沿出现速度模糊,表明地面雷暴大风即将出现,这种速度场特征对抚州雷暴大风预警预报有指示作用。

Based on the data of conventional weather map,ground automatic station and Doppler radar,the ground meteorological elements,circulation situation,weather scale,instability energy and radar echo evolution characteristics of a squall line process in Fuzhou on June 5,2017 are analyzed.The analysis shows that under the circulation situation of"two troughs and one ridge"in middle and high latitudes,the formation of middle and low-level southwest jet contributed to the instability of atmospheric convection,and the ground convergence line is the trigger mechanism of strong convective weather.During the passage of squall line,the meteorological elements such as temperature,pressure and humidity changed dramatically.Before the formation of squall line,low-level warming and humidification played a role in promoting the instability energy accumulated in strong convective weather.The bow echo belt moving eastward rapidly is prone to thunderstorm and gale weather in the place where the echo passes;The front of a large negative velocity area on the radial velocity map has velocity ambiguity,which indicates that the ground thunderstorm gale is about to appear.This velocity field feature has an indication for the early warning and prediction of thunderstorm gale in Fuzhou.