南京空域一次高空致灾冰粒过程的可预报性分析

Analysis of Predictability on a High-Altitude Hail/Graupel Disaster Weather in Nanjing Airspace

利用常规天气分析、雷达资料分析及数值模拟对2011年8月10日南京附近一次引发航空灾害的对流天气过程进行了研究。结果表明,对飞机受损部位检查后推断此次灾害由雹击造成,但是地面未观测到冰雹。当日南京处于副热带高压外围、河套低涡槽前的西南气流中,且位于低层切变线附近,具备发生强对流的潜在条件。垂直方向水汽呈上干下湿分布特征,利于形成冰雹。雷达资料也分析出此次对流系统发展高度较高,核心反射率因子强度较强,垂直累积液态水含量及冰雹指数都较高。从雷达反射率分析得到中气旋、中层径向辐合等特征。此次对流系统的流场结构及动力配置与典型冰雹云一致。此次过程为多单体风暴引发的高空冰雹/霰过程。冰粒子尺寸小,产生高度高,地面温度高,导致冰雹在下降过程中融化。

Synoptic analysis,radar observation and numerical simulation are used to analyze a convection weather process occurred in Nanjing airspace on 10 August 2011 w hich causing aero damage. All analysis support a deduction that this damage caused by hail strike,but there w as no hail observed on the ground. Since hail generates on high level of about thousands of meters,it may melt in the falling process and rain on the ground. Nanjing w as northw estw ard to the subtropical high pressure zone and in the southw est flow before the trough of Hetao low pressure area at that day. It w as near a low level shear line and had sufficient convective potential condition.Dry cold air distributed on upper level and w arm w et air distributed on low er level. This structure is benefit to the generation of hail. Analysis of radar observation show s that this convective system developed very high. Reflectivity in the core w as very strong. VIL and hail index all had high value. And there w ere meso-cyclone and middle altitude radial convergence in this system. The dynamic and flow structure of this system w ere corresponding to typical hail storm. This paper indicates that this high-altitude hail process w as obviously predicted.