盆地西部一次极端短时强降水过程的多源资料分析

Application Analysis of Multi-source Observation Data in Local Extreme Short-time Heavy Rain

利用FY4卫星、多普勒雷达、风廓线雷达、闪电监测以及分钟级降水和风等多源观测资料,从短临监测的角度分析了2020年8月11日四川盆地西部一次极端短时强降水过程。结果表明:本次过程中,多站小时雨量超过100 mm且范围集中。风廓线雷达资料显示,当低空急流加强时,近地层风向发生明显转变,扰动加剧,形成高低空切变线;当强降水发生时,伴有明显的地面辐合线特征,且多普勒雷达呈现出清晰的低层气旋辐合;分钟级降水与降水质心高度、低空急流强度、低层气旋辐合及地面辐合线的形成等具有良好的对应关系;低空急流指数、闪电频次等峰值特征超前强降水峰值0.5~1 h。

Using multi-source observation data such as FY4 satellite,Doppler radar,wind profiler radar,lightning monitoring,minute-level precipitation and wind,an extreme short-term heavy precipitation process in the western Sichuan Basin on August 11,2020 was analyzed from the perspective of short-term monitoring.The results showed that during this process,the hourly rainfall intensity of multiple stations exceeded 100 mm and the range was concentrated.The wind profile radar data showed that when the low-level jet strengthened,the near-surface wind direction changed significantly,the disturbance intensified,and the high-low shear line was formed.When heavy precipitation occurred,it was accompanied by obvious ground convergence line characteristics,and Doppler radar showed clear low-level cyclone convergence.The minute precipitation had a good corresponding relationship with the height of precipitation centroid,the intensity of low-level jet,the convergence of low-level cyclone and the formation of surface convergence line.The peak characteristics such as low-level jet index and lightning frequency could lead the peak of heavy precipitation by 0.5~1 h.