2020年8月28日~29日青海东部一次大到暴雨天气过程分析

Analysis of a Heavy Rain to Rainstorm Weather Process in Eastern Qinghai on August 28-29,2020

针对2020年8月28日~29日青海省东北部一次大到暴雨天气过程,利用常规观测站资料、加密自动站资料、雷达资料、模式预报资料等分析造成此次天气过程的主要成因,结果表明:(1)此次降水过程范围广、强度强,暴雨降水落区集中,降水对流性质明显;(2)高低层配置有利于产生大到暴雨天气,500 hPa短波槽、700 hPa低涡、200 hPa高空急流为降水提供了有利的水汽条件和动力条件,低层偏东南气流输送水汽,中层西南暖湿气流输送孟加拉湾水汽,西南暖湿气流与冷空气交汇于青海省东北部造成此次大到暴雨天气;(3)中小尺度地面辐合线持续东移,为降水提供了触发机制;(4)降水大值区位于山谷之中,地形辐合对降水增幅作用明显。分析结果对今后预报类似大降水天气过程具有重要的参考意义。

Aiming at a heavy rain to rainstorm weather process in northeast Qinghai Province on August 28-29,2020,this paper uses conventional observation station data,encrypted automatic station data,radar data,model forecast data and other analysis to analyze the main causes of this weather process,and the results show that:(1)The precipitation process has a wide range and strong intensity,the rainstorm precipitation falls in the area,and the precipitation convection nature is obvious.(2)The high and low layer configuration is conducive to the generation of heavy rain to rainstorm weather.500hPa short-wave trough,700h Pa low vortex,and 200hPa high-altitude jet stream provides favorable water vapor conditions and power conditions for precipitation,the low-level southeast air flow transports water vapor,the middle southwest warm and humid air flow transports water vapor in the Bay of Bengal,and the southwest warm and humid air flow and cold air converge in the northeast of Qinghai Province caused this heavy rain to rainstorm weather.(3)The small and medium-scale ground convergence line continues to move eastward,which provides a trigger mechanism for precipitation.(4)The precipitation large value area is located in the valley,and the topographic convergence has obvious effect on the precipitation increase.The analysis results have important reference significance for forecasting similar heavy precipitation weather processes in the future.