2019年5月北京一次强降水超级单体特征及成因分析  

Characteristics and causes of a high precipitation supercell in Beijing in May of 2019

作　　者：刘艳杰 王清川 许敏 周贺玲 LIU Yan-jie;WANG Qing-chuan;XU Min;ZHOU He-ling(Langfang Meteorological Service,Langfang 065000,China)

机构地区：[1]廊坊市气象局,河北廊坊065000

出　　处：《气象与环境学报》2021年第4期9-17,共9页Journal of Meteorology and Environment

基　　金：河北省气象局科研项目(19zc06);中国气象局预报员专项(CMAYBY2020-012)共同资助。

摘　　要：利用地面加密站、雷达、微波辐射计和欧洲中心(ERA-interim)逐6 h等多种观测资料,对2019年5月17日北京通州区出现局地极端强降水、雷暴大风和大冰雹天气过程进行分析。结果表明:强降水超级单体是造成本次强对流天气的直接系统,雷达回波可识别出典型特征。午后在地面和超低空北京南部出现小的热低压系统,使得东南风显著加强,一方面提供了充沛的水汽,形成上干下湿的不稳定层结。另一方面,其与高空西风急流相互作用,使得垂直风切变增强,并产生垂直环流。低空逆温层长时间存在,能量不断积累,使午后雷暴爆发性增强成为可能。地面冷池出流与偏南风对峙,形成了假相当位温密集带。冷池长时间稳定维持,其前沿出现一条湿热边界层辐合线,锋生作用使得暖湿气流不断被抬升,对流系统加强并呈准静止状态。在有利的环境背景下,加之充沛的水汽供应和强烈的边界层辐合抬升,雷暴强烈发展形成强降水超级单体,随后分裂,右侧的风暴又发展为超级单体,再次经过通州东部,形成暴雨中心。On the evening of May 17,2019,local extremely heavy precipitation,thunderstorms gales,and hail occurred in Tongzhou District of Beijing.A detailed analysis of this weather process was conducted using various observation data from surface intensive automatic stations,radars,microwave radiometers,and European Center Mesoscale Weather Forecast reanalysis data(ERA-interim)with a temporal resolution of 6 h.The results indicated that a high precipitation supercell is a direct system that caused the severe convective weather,and this typical characteristic can be identified from the radar echo.In the afternoon,a small thermal and low-pressure system occurs near the surface and at the ultra-low altitudes in the southern part of Beijing,which makes the southeasterly wind significantly strengthened.On the one hand,it provides abundant water vapor and forms an unstable stratification of upper dry and lower wet.Meanwhile,the interaction between the low-level southwesterly flow and the upper-level westerly jet enhances vertical wind shear and produces vertical circulation.The low-level temperature inversion layer exists for a long period,and the energy continues to accumulate,making it possible to increase the explosiveness of thunderstorms in the afternoon.The outflow of the surface cold pool flow confronts the southerly wind,forming a dense zone of surface pseudo-equivalent potential temperature.The cold pool was maintained steadily for a long time,and a moist-warm convergence line of the boundary layer occurred ahead of the cold pool.The frontogenesis causes the warm and humid airflow to be continuously uplifted,and the convective system is strengthened and in a quasi-static state.In a favorable environment,combined with sufficient water vapor supply and strong boundary layer convergence and uplift,thunderstorms strongly develop into a high precipitation supercell.Then the storm splits,and the storm on the right develops into a supercell,passing through eastern Tongzhou again and forming the rainstorm center.

关 键 词：强降水超级单体 低层东南风 逆温层 冷池 

分 类 号：P458.3[天文地球—大气科学及气象学]