【摘要】 基于固原C波段多普勒天气雷达和X波段双偏振雷达观测资料,结合ERA5逐时再分析、葵花8号卫星、常规气象观测等多源资料,对2021年7月12日宁夏六盘山区一次局地特大冰雹（直径≥5 cm）的成因和雷达观测特征进行分析。结果表明,多单体风暴合并发展形成的超级单体导致此次特大冰雹出现。六盘山区地面中尺度辐合线、中尺度气旋和局地环流是中尺度对流系统的主要触发、增强系统,同时也影响其移动方向。大冰雹出现时,C波段雷达反射率因子（Z）≥65 dBz、三体散射长钉（TBSS）长度≥20 km、垂直累积液态水含量（VIL）≥40 kg·m^-2;X波段雷达低层水平反射率因子（ZH）高值区的相关系数（CC）<0.8,中高层Z_H高值区的差分反射率因子(Z_DR)和差分传播相移率(K_DP)为负值、CC<0.8。特大冰雹出现时,C波段雷达Z≥70 dBz、TBSS长度≥30 km、VIL≥50 kg·m^-2;X波段雷达低层ZH高值区的CC<0.6,CC<0.5的区域形成的“空洞”有助于识别空中特大冰雹所在区域及高度。有界弱回波区附近的Z_DR柱和CC环可指示超级单体中高层强上升气流的位置,Z_H和双偏振参量特征对不同尺寸冰雹的识别和预警具有很好的指示意义。更多还原

【Abstract】 Based on the observation data by Guyuan C-band Doppler weather radar and X-band dual polarization radar,combined with ERA5 hourly reanalysis data,Himawari-8 satellite images and conventional observation data,we analyze the causes and radar observation characteristics of a local outsize hail（diameter≥5 cm） which occurred in Liupan Moutains of Ningxia on 12 July 2021.The results show that the supercell storm formed by the merger and development of multicell storm led to the occurrence of outsize hail.The mesoscale surface convergence line,mesoscale cyclone and local circulation in Liupan Moutains were the main triggering and enhancing systems of mesoscale convective system（MCS）,and also affected the moving direction of MCS.When the large hail occurred,the C-band radar reflectivity factor（Z） ≥65 dBz,three-body scatter spike（TBSS） length> 20 km,and vertically integrated liquid water content（VIL）≥40 kg·m^-2.The correlation coefficient（CC） in the high-value zone of the low layer horizontal reflectivity（Z_H） of X-band radar was less than 0.8,and the differential reflectivity（ZDR） and specific differential phase（KDP） of the mid-and high-layers Z_H high-value zone were negative with CC<0.8.When the outsize hail occurred,Z≥70 dBz,TBSS length≥30 km and VIL≥50 kg·m^-2 for the C-band radar.CC in the low layer Z_H high-value zone of the X-band radar was less than 0.6,and the "hole" formed in the area with CC<0.5,was useful to identify the area and altitude of outsize hail in the air.Z_DRcolumns and CC rings near the bounded weak echo zone could indicate the position of strong updrafts in the middle and upper layers of supercell storm.So,Z_H and dual polarization parameter characteristics have good indicative significance for the identification and warning of hails in different sizes.更多还原