庆阳市2021年“8.18”旱涝急转型暴雨过程诊断分析

A Diagnostic Analysis for the Abrupt Change of Drought and Flood on August 18,2021 in Qingyang City

利用实况站点雨量、Micaps数据、多普勒雷达等资料对2021年8月18-19日庆阳市“旱涝急转”型暴雨进行诊断分析,结果表明,此次暴雨是贝湖低槽东移冷空气和副高外围西南暖湿气流共同作用的结果;500hPa高空槽东移为暴雨产生提供了冷空气;700hPa切变线是暴雨触发系统;庆阳市上空的辐合上升、不稳定能量,为暴雨提供了动力条件;低层水汽饱和、中层干空气卷入为短时强降水提供了热力不稳定条件;雷达对流云团对强对流也有很好的指示意义。

Using the actual rainfall,Micaps data and Doppler radar data to diagnose and analyze the rainstorm of“abrupt change of drought and flood”in Qingyang city from August 18 to 19,2021.The results showed that the rainstorm was caused by the cold air moving eastwards from Lake Baikal Trough and the southwest warm and humid air flow outside the Subtropical High.The 500 hPa Upper Trough moving eastwards provided cold air for the rainstorm and the 700 hPa Shear Line is the rainstorm triggering system.The convergence rising and unstable energy over Qingyang city provided dynamic conditions for the rainstorm while low level water vapor saturation and middle level dry air involvement provided thermal instability conditions for short-time heavy precipitation.The radar convective cloud cluster is also a good indication of strong convection.