本文利用地面逐小时气象观测资料、高空观测资料、多普勒雷达产品和FY-2H卫星的云顶黑体亮温(Black Body Temperature,TBB)资料,分析了2022年4月11日四川盆地一次极端大风天气过程的形成原因和演变特征,得到如下结论:①此次极端大风天气过程因干冷空气进入盆地而触发,地面辐合线的强迫抬升作用加强了此次风暴天气;②过程中剧烈天气多发生于中尺度对流系统合并加强时期,且位于对流云团前侧TBB梯度大值区以及TBB低值中心附近;③飑线过境时强的冷池作用,飑锋前后变压梯度强、密度流强,是导致地面极端大风的重要原因;④风暴前侧入流、后侧入流和强的中层径向辐合为极端大风的出现提供了有利配置;而强反射率因子核和垂直液态含水量大值区的迅速下降意味着系统内部剧烈降温而产生了湿下击暴流,加剧大风强度.
Analysis on Formation Reason of an Extreme Gale in Sichuan Basin
Convective extreme gale is one of the main types of severe convective weather that causes meteorological disasters.It has the characteristics of strong locality,short life history,and difficulty in forecasting.In recent years,extreme gale events occur frequently in China,causing serious economic losses to the society and public.However,the characteristics,impact systems,and causes of extreme gale vary in different regions.At present,there are many studies on the background of extreme gales in the Sichuan Basin,but research on convective potential and Doppler radar characteristics is still relatively limited.Therefore,it is necessary to conduct detailed research on typical cases of extreme gales that occur.On 11 April 2022,a rare extreme gale process occurred in Sichuan Basin with maximum wind speed reaching 37.4 m/s.During this period,there were also hail and short-time heavy rain.To explore the causes of this extreme gale process,this paper conducts research and analysis on circulation situation,convective environmental conditions,and meso-small scale system characteristics by using surface hourly meteorological observation data,upper-air observation data,Doppler radar products,and black body temperature data from the FY-2H satellite,providing reference for future forecasting of extreme gale weather in the Sichuan Basin.The conclusions are as follows:(1)This extreme gale process was triggered by the dry and cold air entering the basin,and the forced uplift of the ground convergence line strengthened the storm weather;the unstable stratification featuring"upper dry and lower humid",a large temperature lapse rate,vertical wind shear with moderate intensity,and high CAPE value,all provided favourable convective environmental conditions for this extreme gale process,(2)The severe weather of this process mostly occurred during the period of severe development and consolidation of the Mesoscale Convective System,and was located in the high-value area of TBB gradient in front of the convective cloud clusters and near the low-value centre of TBB,(3)The main factors causing extreme strong wind on the ground included the cold pool effect when the squall line passed through,and the strong pressure gradient and density current,(4)The front inflow and the rear inflow of the storm together with the strong mid-altitude radial convergence were favourable conditions for the emergence of extreme strong wind;the sharp decrease of the reflectivity factor core and the maximum vertically integrated liquid water implied the humid critical strike flow caused by a sharp drop in temperature in the system,which increased the intensity of strong wind.
万方数据
维普
