一次线状中尺度对流系统冷池作用的分析及地形敏感性试验OA

Based on multi-source observations,a leading stratiform-precipitating linear Mesoscale Convective System(MCS)affecting Huaibei area on May 23,2020 was analyzed.Special attention was paid to the influence of the surface cold pool on the convection,which was further simulated by the WRF model,and effects of the mountainous terrain in the central part of Shandong on MCS and the characteristics of the cold pool were considered.Results are as follows:(1)during the linear MCS event,the atmospheric background exhibited strong dynamic forcing and favorable convective conditions,resulting in widespread thunderstorms and short-term heavy precipitation over the eastern Shandong and northern Jiangsu.(2)A significant negative correlation exists between the temperature tendency of the cold pool and the intensity of the radar echo.The cold pool lagged behind the strongest convection of MCS.When they separated,the convection of MCS weakened.(3)During the development and enhancement stage of MCS,the surface cold pool enhanced the convective instability at the low-level near the front,promoting the surface convergence.Thus,the low-level ascending motion was strengthened,facilitating the enhancement and persistence of convection of MCS.In the later stage,as the slanting upward motion at the front edge of the cold pool weakened,the compensatory subsidence airflow on the rear side began to suppress the convection of MCS.(4)The terrain sensitivity experiment has revealed that the mountainous terrain in the central part of Shandong has played a positive role in initiating the convection.The cold pool tended to move slowly,and the surface convergence on the front side was relatively strong during the descent process,which further enhanced the linear MCS convection.Therefore,the convection of MCS was well organized during its impact on Jiangsu.This study provides new insights into the understanding of impacts of cold pool and terrain on the convection of linear MCS,and offers a scientific basis for the forecast of similar processes.