一次极端特大暴雨天气过程C波段双偏振雷达资料分析

Analysis of C-Band Dual-Polarization Radar Data in an Extreme Rainstorm Process

为探究C波段双偏振雷达资料在暴雨监测预警中的应用,该文利用遵义市C波段双偏振雷达资料及常规观测资料对2020年6月12日凌晨遵义市碧峰镇发生的1次极端特大暴雨天气过程进行分析,结果表明:①本次碧峰极端暴雨天气过程产生于高温高湿的背景下,属于低涡切变型暖区性质降水,500 hPa高原槽后干冷空气的叠加促进了强降水天气过程的爆发。②过程由深厚的低质心强降水对流单体引发,存在中尺度辐合区且与强降雨持续时间对应。③1.5°仰角Z_(DR)、K_(DP)值变化趋势与地面分钟雨量一致,有跃增现象,且超前15~20 min。④低层Z_(DR)大值区与反射率因子大值区重合,反映了强降水过程的主要落区。中尺度辐合造成强的上升气流使得低层的Z_(DR)和CC值显著减小,同时其附近部分大雨滴被抬升至4 km高度形成Z_(DR)大值中心。

In order to explore the application of C-band dual-polarization radar data in rainstorm monitoring and early warning,this paper uses C-band dual-polarization radar data and conventional observation data in Zunyi City to investigate an extremely heavy rainstorm process that occurred in Bifeng Town,Zunyi City on the early morning of June 12,2020.The results show that:①The extreme rainstorm weather process in Bifeng occurred under the background of high temperature and humidity,which belongs to the low vortex shear type warm zone precipitation.The superposition of dry and cold air behind the 500 hPa plateau trough promotes the outbreak of the heavy rainfall process.②The process is initiated by a deep low-centroid heavy rainfall convective cell,with a mesoscale convergence zone corresponding to the duration of heavy rainfall.③The change trend of the 1.5°elevation angle Z_(DR) and K_(DP) is consistent with the minute rainfall on the ground,and there is a jump phenomenon,and it is 15 to 20 minutes ahead.④The low-level Z_(DR) high-value area coincides with the reflectivity factor high-value area,reflecting the main falling area of the heavy precipitation process.The strong updraft caused by the mesoscale convergence causes the Z_(DR) and CC values in the lower layer to decrease significantly,and at the same time,some large raindrops in the vicinity are lifted to a height of 4 km to form the center of the Z_(DR) maximum value.