两高切变型四川盆地大暴雨天气过程机制研究

Mechanism of Heavy Rainfall Weather Process in Sichuan Basin with Two High Shears

利用常规观测和EC数值模式资料,对2020年8月12~13日四川盆地大暴雨天气的环境条件、水汽条件、能量条件、不稳定层结、MCS系统演变进行分析。结果表明:本次盆地大暴雨属于“两高切变”型,是在高能高湿环境条件下,北方干冷空气入侵盆地触发锋线对流系统,盆地南部受地形强迫抬升影响触发对流系统,在高空切变线上合并加强,造成四川盆地大暴雨过程。贵州高原的强水汽输送是此次大暴雨的重要水汽条件,对流云团合并加强是造成局地特大暴雨的重要特征。基于EC数值模式资料分析的盆地暴雨落区比实况探空更加清晰。

Using conventional observation and EC numerical model data,the environmental conditions,water vapor conditions,en-ergy conditions,unstable stratification and MCS system evolution of heavy rainstorm weather in Sichuan Basin from 12 to 13 August 2020 were analyzed.The results show that the heavy rain in the basin belongs to the'two high shear'type.Under the condition of high energy and high humidity,the northern dry and cold air invades the basin to trigger the front convective system,and the southern basin is affected by the forced uplift of the terrain to trigger the convective system,which is combined and strengthened on the upper shear line,resulting in the heavy rain process in Sichuan basin.The strong water vapor transport over the Guizhou Plateau is an important water vapor condition for this heavy rain,convective cloud cluster consolidation is an important feature of local torrential rain and the rainstorm area based on EC numerical model data analysis is clearer than the actual sounding.