黔北一次冰雹天气过程C波段双偏振雷达资料分析

【目的】为进一步探索C波段双偏振雷达参数指标的本地化运用。【方法】利用习水C波段双偏振雷达资料、地面自动站资料、探空资料，对2022年3月16日发生在黔北的一次冰雹天气过程成因以及双偏振雷达回波特征进行分析。【结果】（1）此次强对流天气发生在500 hPa前倾槽前、低层低涡切变东南侧，中低空急流的北侧及地面低压倒槽内，同时午后升温及中高层干冷平流入侵，使得层结更趋于上干冷下暖湿的不稳定层结，冷锋前沿的地面辐合线为过程提供了触发机制。（2）过程由多单体风暴引发，最大反射率因子达65 dBz，40 mm冰雹出现了三体散射，剖面图中出现了悬垂结构和有界弱回波区，低层观测到辐合速度对。（3）对比30 mm和40 mm的冰雹双偏振参数发现：融化层以上冰雹Z_DR在-1~0.2 dB，CC值在0.90~0.99之间，K_DP均为0；从融化层以下，30 mm冰雹CC值在0.70~0.90，40 mm冰雹CC值在0.80~0.97，两者有所区别，Z_DR也有明显增加，在0~4 dB之间；由于融化层以下大雨滴的混合，K_DP在0~3.1 °·km^-1之间。（4）大冰雹偏振参数出现明显Z_DR柱、K_DP柱，CC谷，CC图中出现明显的非均匀波束充塞，Z_DR和CC图中有明显的三体散射现象。【结论】该文仅是对一次多单体天气过程个例的偏振参数特征粗略分析，未来仍需分析更多个例用以完善C波段双偏振天气雷达在强对流天气中各种偏振参数的标准，为实际业务提供更精准的参考。

Analysis of C-band Dual-polarization Radar Data of a Hailstorm in Northern Guizhou

In order to further explore the local application of C-band dual-polarization radar parameter indicators, this paper analyzes the causes and the dual-polarization radar echo characteristics of a hailstorm that occurred in northern Guizhou on March 16, 2022, by using Xishui C-band dual-polarization radar data, ground-based automatic station data, and sounding data. The results show that: (1) This severe convective weather occurred in front of the 500 hPa forward trough, southeast of the low-level low vortex shear, north of the low-and mid-level jet streams and within the ground low-pressure inversion trough. At the same time, the afternoon warming and the intrusion of the mid-upper level dry and cold advection made the stratification more inclined to be unstable, that is, dry and cold in the upper level and warm and humid in the lower level. Moreover, the ground convergence line at the front of the cold front provided the triggering mechanism for the hail process. (2) This hail process was triggered by a multi-cell storm with a maximum reflectivity factor reaching 65 dBz and three-body scattering out of the 40 mm hailstones. There were overhanging structures and bounded weak echo zones in the cross-sections, and convergence velocity pairs were observed in the lower layers. (3) The comparison of the double polarization parameters of 30 mm and 40 mm hailstones suggest that the Z_DR of hailstones above the melting layer is in the range of -1 to 0.2 dB, the CC value is between 0.90 and 0.99, and the K_DP is 0. From the polarization parameters below the melting layer, the CC values of the 30 mm and 40 mm hailstones are in the range of 0.70-0.90 and 0.80-0.97 respectively, and the Z_DR also has increased significantly reaching 0-4 dB. K_DP is between 0 and 3.1°·km^-1 due to the mixing of large raindrops below the melting layer. (4) The polarization parameters of large hailstones show obvious Z_DR columns and K_DP columns. For CC valleys, obvious non-uniform beam filled in the CC diagrams, thus obvious three-body scattering in the Z_DR and CC diagrams appears. In summary, this paper is only a rough analysis of a multi-cell convective weather process, and the characteristics of the polarization parameters need to be further discussed. In the future, more cases need to be analyzed to improve the standards of various polarization parameters of the C-band dual-polarization weather radar in the severe convective weather and to provide a more accurate reference for the actual operation.