一次强冰雹天气诊断分析

Diagnostic Analysis of a Heavy Hail

利用常规气象资料和沈阳多普勒雷达,从天气背景、温度对数压力图和雷达反射因子演变特征方面,对2009年7月22日辽宁省昌图县北部地区的冰雹天气过程进行分析。结果表明,该次冰雹天气发生在东北低涡后部,冷涡旋转东移触发低空切变线形成。冰雹发生前,大气有不稳定能量,低空切变线加剧了大气层结不稳定,促进不稳定能量释放,产生冰雹天气。多普勒雷达资料表明,强对流天气是对流单体,发展强盛时有钩状结构,强回波区为55～70dBz。

Using the conventional meteorological data and Shenyang Doppler Radar,the hails in Northern part of Changtu on July 22,2009 were analyzed from weather background,energy-per-unit diagram and the evolution of characteristics of the radar reflectivity factor.The results showed that the hail occurred in the Northeast vortex rear.It was formed when the cold vortex rotate eastward trigger low-level shear line.Before the hail occurred,there was unstable energy in atmosphere.Low-level shear line strengthened the instability in atmospheric stratification which promoted the unstable energy to release and brought the hail weather.Doppler Radar data indicated that the strong convective was the convective cells.There was hook structure when it was strong development,and strong echoes were between 55-70 dBz.