2019年7月3日辽宁开原超强龙卷形成及演变特征分析

Analysis of the formation and evolution of super tornado occurred in Kaiyuan of Liaoning province on July 3,2019

综合利用高时空分辨率多源观测资料,对2019年7月3日辽宁省开原市一次EF4级超强龙卷过程(简称开原龙卷)的天气背景、环境物理量参数、龙卷形成发展机制等进行分析。结果表明:开原龙卷发生在东北冷涡的西南象限,850 hPa切变线南侧及地面西南气流暖湿环境中,地面与925 hPa温差达11℃,近地面温度垂直递减率大,系统配置具有上干冷、下暖湿特点。受低层暖湿气流影响的同时,开原周边地区对流抑制能量接近于零,有利于强对流天气的发生。开原龙卷出现在东北冷涡涡旋云系的后端,对流云的快速爆发生长期中,处于快速降温区的北边界。多普勒雷达为典型的超级单体回波特征,龙卷出现在钩状回波顶端,强回波梯度区左侧的上升气流交界处。

Based on multi-source observations with the high spatiotemporal resolution,synoptic situation,and environmental physical parameters,the formation and development mechanisms of an EF4-level strong tornado(Kaiyuan tornado for short)occurred in Kaiyuan of Liaoning province on July 3,2019,were analyzed.The results show that the Kaiyuan tornado occurs in the southwest quadrant of the northeast cold vortex,on the south side of the 850 hPa shear line,and in the warm and humid environment of the southwest airflow on the ground.The temperature difference between ground and 925 hPa reaches 11℃,and the vertical lapse rate of the near-ground temperature is large.The system configuration has the characteristics of dry and cold above and warm and wet below.Under the influence of low level warm and wet air,the convective suppression energy is close to zero in the area around Kaiyuan,which is conducive to the occurrence of strong convective weather.Kaiyuan tornado appears in the rear end of the northeast cold vortex cloud system,and in the rapid growth period of convective cloud,it is in the northern boundary of the rapid cooling area.Doppler radar shows a typical supercell echo.The tornado appears at the top of the hook echo and the junction of updraft on the left of the strong echo gradient area.