广西南宁一次"龙舟水"暴雨空报事件对流生消成因分析OA北大核心CSTPCD

On June 13,2022,a large-scale regional rainstorm event occurred in Guangxi.During this period,a rainstorm false alarm was issued for the downtown area of Nanning.The echo attenuated in the north side of Nanning City,maintained in the east side and developed in the south side,which made the process com-plicated.This article investigates the causes for the generation and dissipation of the convection during this event by utilizing various observational data and ERA5 reanalysis data.The results are as follows.The circulation background of this process was the typical heavy rainfall circulation and ambient condition in the first rainy season in Guangxi.However,under the combined influence of synoptic-scale cold advection and storm cold pool,the cold air quickly moved over Nanning City,and the outflow boundary formed by the storm in the north side of Nanning moved away from the storm parent body.Meanwhile,the low-level wa-ter vapor transport in the front of the storm moved eastward,resulting in poor thermodynamic and dynam-ic conditions,leading to the attenuation and dissipation of echoes in the north side of Nanning City.In the east side of Nanning City,the outflow boundary of the storm was next to the storm parent body during its advancing,and the lower layer ahead of the storm kept the southwest jet stream so that the storm was strengthened or sustained by continuous convective cells triggered along the outflow boundary.There was a low-level high temperature and high humidity environment in the south side of Nanning,which was con-ducive to the reconstruction or enhancement of convective available potential energy.Based on the above,a conceptual model of the evolution mechanism of convection generation and dissipation in this process has been built,and with it,the short-time and nowcasting forecasts can be supplemented and corrected by ana-lyzing the evolution of cold pool,outflow boundary and ambient conditions.