摘要
基于南京信息工程大学C波段双偏振雷达观测数据,结合探空和地面实况资料,对2016年7月7日发生在南京地区的一次强降水超级单体过程进行双偏振雷达变量特征分析。结果表明:(1)当后向传播和多单体合并造成02—03时出现129.2 mm·h^(-1)极端强降水时,最强回波Z H约60 dBZ,差分反射率因子Z DR达5 dB,差分相位常数K DP超过8(°)·km^(-1)。K DP大值区与地面上小时雨强极大值中心存在较好的对应关系。反射率因子Z H、差分反射率因子Z DR、差分相位常数K DP与小时雨强也有显著的正相关。(2)强降水超级单体发展旺盛阶段,垂直运动明显增强,上升气流活跃,冰雹和霰占的比例高,-20°C以上存在深厚的混合相态区,闪电的频次和强度明显增强,分钟雨强增大。相关系数小值区ρHV以及Z DR弧超前于超级单体1个体扫发生,并可以指示超级单体底层上升气流区的位置。Z DR环与相关系数ρHV环对确定中层上升气流的位置具有指示意义。Z DR柱可用于识别主上升气流的位置,K DP柱的位置与地面小时雨强中心存在较好的对应关系。
Based on the combined observations from a C-band polarimetric radar in Nanjing University of information Science and Technology,by using the conventional upper-air and surface datasets,the polarimetric radar variable characteristics from an intense rainfall event caused by supercell storm in Nanjing city on July 7,2016 were analyzed.Results can be summarized as follows:(1)when the extreme hourly precipitation(129.2 mm·h^(-1)at 02∶00 BST-03∶00 BST)occurred by back-building convections,the maximum value of Z H is about 60 dBZ,Z DR is around 5 dB,and K DP exceeds 8(°)·km^(-1).There is also a good correlation between the maximum center of ground hourly rainfall and areas of extreme polarimetric radar variables,especially for K DP values.(2)During the mature stage of the supercell storm,updrafts are enhanced and more active ice-phase microphysical processes occur above the freezing level,with large proportions of graupel(hail)exist and frequent lightning records are also observed.Correspondingly,the minute rainfall intensity also reaches peak values when the supercell storm appears.Moreover,small value areas ofρHV and Z DR arcs occur ahead of the formation of supercell and can indicate the position of the updraft area at the bottom of the supercell.Z DR ring andρHV ring are also good indicator to determine the position of updraft in the middle layer.Z DR column can also be used to identify the location of updraft regions,while the location of K DP column indicates the ground hourly rain intensity center.
作者
袁媛
孙康远
陈刚
董金芳
夏斌
YUAN Yuan;SUN Kangyuan;CHEN Gang;DONG Jinfang;XIA Bin(Nanjing Meteorological Bureau,Nanjing 210019,China;Key Laboratory of Transportation Meteorology,CMA,Nanjing 210041,China;Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210041,China;Shaanxi Agricultural Remote Sensing and cash crop Meteorological Service Center,Xi an 710000,China;Jiangning Meteorological Bureau,Nanjing 211100,China)
出处
《气象科学》
北大核心
2022年第6期825-834,共10页
Journal of the Meteorological Sciences
基金
北级阁开放研究基金资助项目(BJG201905)
江苏省自然科学基金资助项目(BK20171094)。
关键词
双偏振雷达
超级单体
强降水
微物理特征
polarimetric radar
supercell
heavy precipitation
microphysical characteristics
