冰雹不同发展阶段的双偏振参量分析及风场反演

Dual-Polarization Parameter Analysis and Wind Field Inversion of Hail in Different Development Stages

摘要: 为了研究冰雹云过程在不同发展阶段的双偏振参量特征，本文基于厦门S波段双偏振多普勒天气雷达资料和双雷达风场反演获得的降水场气流结构特征，对冰雹云超级单体的发展和成熟阶段的微物理特征和动力结构进行分析。结果表明：发展阶段，低仰角能观测到ρhv谷，中层仰角能观测到ZDR柱和KDP柱；ZDR柱对应着大滴粒子，与粒子相态识别结果相符。成熟阶段，云体移动方向前侧观测到ZDR弧及KDP印，Z高值，ZDR低值以及KDP的缺值可以识别云中的大冰雹区，对应粒子识别结果也是雨加雹。高层出现的ρhv低值，Z高值及ZDR负值区，该区域可以表征为冰雹区，与粒子识别算法结果一致。冰雹云发展阶段，低层水平流场出现气旋性辐合，云体内部形成较强的上升运动。成熟降雹阶段，低层水平维持气旋性流场的同时，高层出现反气旋性流场。最大垂直速度达48 m/s，出现在超级单体悬垂部。降雹时段，出现明显的下沉气流，强回波底及地。

Abstract: Based on the S-band dual-polarization operational radar at Xiamen and structural characteristics of the flow field obtained by dual radar wind field retrieval, the microphysical characteristics and dynamic structure of the hailstorm supercell during the developmental and mature stages is analyzed to study the characteristics of dual polarization parameters of hail cloud process in different development stages. In the development stage, ρhv valleys can be observed at low elevation angles, and ZDR columns and KDP columns can be observed at middle elevation angles; ZDR columns correspond to large droplets, which are consistent with the results of hydrometeor classification. At the maturity stage, ZDR arcs and KDP foot were observed in front of the direction of cloud movement, high Z values, low ZDR values, and missing KDP values can identify large hail areas in the cloud, and the corresponding hydrometeor classification results are rain and hail. The areas of low ρhv value, high Z value, and negative ZDR value appearing in the upper layer can be characterized as hail area, which is consistent with the result of hydrometeor classification algorithm. At the stage of hailstorm development, cyclonic convergence occurred in the low-level horizontal flow field, and a strong frank updraft formed within the cloud body. At the mature hailfall stage, while the cyclone circulation is maintained at the lower level, the anticyclonic circulation appears at the upper level. The strongest updraft is 48 m/s at the height of supercell overhang. Systemic downdraft appeared during weakening period of system, and strong echo reached the ground.