通辽市一次冰雹天气中尺度分析

Mesoscale Analysis of a Hail Event in Tongliao

利用常规观测资料、ERA(0.25°×0.25°)再分析资料、通辽多普勒雷达(CINRAD/CB型)探测资料和卫星云图(FY-4A)资料,对2022年6月20日通辽市冰雹天气进行成因分析。结果表明:500 hPa冷涡底部短波扰动和低层低涡切变环境中雹暴云团发展,低层适当的水汽条件、较大的对流有效位能、中高层干冷空气叠加在低层暖湿空气上形成了对流不稳定层结、较强垂直风切变和地面干线的触发作用下不稳定能量释放。对流有效位能(CAPE)、K指数、SI、总指数(TT)等参数均达到强对流天气阈值。两个尺度较小的雹暴云团均沿着环境引导气流方向自西北向东南移动。反射率因子剖面图上,呈中高层回波悬垂,低层弱回波区、回波墙、假尖顶回波等特征。移动较快的“W”形弓形回波有明显的前侧入流缺口和后侧入流缺口。前侧入流缺口有强的上升气流,有利于冰雹的增长,后侧入流缺口表明有强的下沉气流,可能引起雷暴大风。垂直累计液态水含量跃增并维持较高值。雷达产品特征均较好地反映发生冰雹天气。

This paper analyzed the causes of the hailstorm in Tongliao on June 20,2022 based on routine observation data and satellite cloud image data.The results showed that:hailstorm cloud developed with 500 hPa shortwave trough disturbance and low eddy shear.Appropriate water vapor at lower levels,large convective effective potential energy,the convective instability stratification caused by dry and cold air mass being above warm and humid air mass,strong vertical wind shear,and ground drylines could trigger the release of unstable energy.Several parameters had reached the thresholds of severe convective weather,such as CAPE,K,SI and TT index;Two smaller hailstorm clouds moved from northwest to southeast in the direction of the steering flow.The reflectivity profile features showed echo overhang at the middle-upper layer weak echo region at the low layer,echo wall,false cusp echo and so on.The fast-moving W bow echo had a front inflow notch and a rear inflow notch.The strong updraft in the front inflow notch could prompt hailstone growth while the downdraft in the rear inflow notch may cause thunderstorm gales.And vertically Integrated Liquid Water shot up and stayed at a high level.Overall,the radar products can identify hail weather well.