一次强对流天气过程双偏振雷达产品特征分析

Analysis of the Characteristics of Dual-polarization Radar Products for an Intense Convective Weather Process

根据Micaps常规气象观测数据、南海区和三水区X波段双偏振多普勒天气雷达资料,对2017年7月26日佛山市南海区一次局地致灾性雷暴大风天气过程中双偏振多普勒天气雷达产品演变特征进行分析。结果表明:该次午后局地致灾性强对流天气是由2条阵风锋的交汇而触发的。阵风锋具有差分反射率Z_(DR)为较大正值、相关系数ρ_(hv)值小、传播相移差ΦDP为正值的特征,与昆虫的双偏振回波特征相似。当雷暴发展旺盛时,雷暴单体中以扁椭球状的大雨滴为主;当雷暴减弱时,以接近球状的小雨滴为主。

With conventional meteorological observations of Micaps and X-band dual-polarization Doppler weather radar echoes from the districts of Nanhai and Sanshui, the evolution characteristics of a local disaster-inflicting thunderstoml, which took place in Nanhai District, Foshan on July 26, 2017, are studied. The result is shown as follows. A post-midday process, the intense convective weather was triggered by the convergence of two gust fronts. The gust front is characteristic of a large positive differential reflectivity ZDR, a small con＇elation coefficient Phv, and a positive differential phase φDp, which is similar to the dual polarization echoes of insects. When the thunderstorm developed vigorously, storm cells were mainly made of large-sized rain drops in the shape of flat and elliptical balls; when it weakened, they mainly consisted of small rain drops in near-spherical shape.