黄河三角洲地区冰雹过程雷达特征分析

Radar characteristic analysis of hail process in the Yellow River Delta area

利用新一代天气雷达产品资料,统计分析了2016—2020年192个黄河三角洲地面降雹个例,从基本反射率因子(R)、垂直积分液态含水量(VIL)、垂直积分液态含水量密度(VILD)特征值等方面归纳出预警临近指标,并应用这些指标分析了2019年5月12日一次局地强对流天气过程。结果表明,风暴单体A3、X3初始回波主要生成于0℃层和-20℃层之间,跃增阶段R、单位体回波厚度平均每个体扫间隔分别增加5.8 dBZ、1.5 km以上,孕育阶段VIL、强回波最高高度(H45)平均每个体扫间隔分别增加5.6 kg·m^(-2)、0.7 km以上,且至少出现一次VIL跃增10 kg·m^(-2)以上,降雹阶段回波顶高、H45、VIL值迅速减少,具有明显的冰雹云生命史特征;两个风暴单体在孕育、降雹阶段表现出不同的发展演变特点,对冰雹的形成和维持有明显的影响。

Based on the product data of the new-generation of weather radar product data,192 cases of ground hail in the Yellow River Delta during 2016—2020 were statistically analyzed,and the early warning approaching indicators were summarized from the basic reflectivity factor(R),vertical integrated liquid water content(VIL),and vertical integrated liquid water content density(VILD).A local severe convective weather process on 12 May,2019 was also analysedusing these indicators.The results showed that the initial echoes of storm monomer A3 and X3 were mainly generated between 0℃and-20℃layers,the average R and echo height per body sweep interval increased by 5.8 dBZ and 1.8 km or more,respectively in the leapfrog phase.In the breeding stage,the average VIL and strong echo height(H45)per body sweep interval increased by 5.6 kg·m^(-2)and0.7 km or more,respectively,and at least once VIL jump increased by more than 10 kg·m^(-2).In the hail drop stage,the echo height,H45and VIL value rapidly reduced,with the obvious life history characteristics of hail cloud.The two storm cells showed different development and evolution characteristics during the gestation and hail suppression phases,which had a clear effect on the formation and maintenance of hail.