基于双偏振雷达资料的一次强降水超级单体风暴特征分析

ANALYSIS OF THE CHARACTERISTICS OF A HEAVY PRECIPITATION SUPERCELL STORM BASED ON DUAL POLARIZATION RADAR DATA

基于山东济宁S波段双偏振多普勒天气雷达探测数据,结合探空和地面实况资料,对2021年6月14日发生在山东单县一带的强降水超级单体双偏振参量特征和微物理特征进行了分析。结果表明:环境整层湿度较大,CAPE较强,0℃层高度较高,利于强降水产生,0~6 km具有中等强度垂直风切变,利于超级单体风暴产生与维持。单县超级单体风暴旺盛阶段强度在60~65 dBZ,强中心高度基本位于0℃层高度之下,质心偏低。K_(DP)柱的高度与宽度明显大于ZDR柱,强盛宽阔的上升气流将一定浓度、小的液态粒子带至较高高度并持续较长时间。风暴低层左侧一直存在K_(DP)大值区,同时也存在3°/km以上的K_(DP)高值区,液态粒子浓度较高,最大分钟降水量维持在3 mm以上。风暴低层右侧有明显的入流缺口,有明显的ZDR弧,表现为偏大的液态粒子。环境0℃层高度以上较厚的厚度内含有丰富的液态粒子和冰相粒子,丰富的冰相粒子下降到0℃层高度之下出现明显融化,在低层强切变的“筛选”作用下,风暴右侧入流与下沉气流结合区以大的液态粒子为主,浓度小,降水强度较弱。风暴左侧低层为高浓度液态粒子,从而产生高强度降水。

Based on the detection data of an S-band dual polarization Doppler weather radar in Jining,Shandong province,and combined with sounding and surface meteorological observation data,the characteristics of dual polarization parameters and microphysical characteristics of supercells in a heavy rainfall in Shanxian,Shandong province on June 14,2021 are analyzed.The results are shown as follows.The humidity of the whole layer of the environment is relatively high,CAPE is relatively strong,and the height of the 0℃layer is relatively high,which is conducive to the generation of heavy precipitation.Vertical wind shear at moderate intensity is found at the heights of 0~6 km,which is conducive to the generation and maintenance of the supercell storm.The intensity of the supercell storm in Shanxian is 60~65 dBZ at the peak stage,the height of an intensity center is basically below the 0℃level,and the core of mass is low.The height and width of the K_(DP)column are much larger than that of the ZDR column.A strong and wide updraft brings small liquid particles with some degree of concentration to a higher height for extended time.On the left side of the lower storm level,there are always areas of large K_(DP)values,with some of them more than 3°/km.The concentration of liquid particles is high,and the maximum precipitation rate is maintained at more than 3 mm per minute.On the right side of the lower layer of the storm,there are an inflow gap and a ZDR arc clearly,shown as relatively large liquid particles.There are abundant liquid-and ice-phase particles in the deep thickness above the height of the 0℃layer in the environment.When abundant ice-phase particles drop below the height of the 0℃layer,they melt by large amount.Under the"screening"effect of a strong shear in the lower layer,the junction area between the inflow and the downdraft on the right side of the storm is dominantly with large liquid particles with low concentration and rainfall intensity is low.The lower layer on the left side of the storm has high concentration of liquid particles,resulting in high-intensity precipitation.