VIL和VIL密度在冰雹云判据中的应用

Application of VIL and VIL Density in Warning Criteria for Hailstorm

利用2002--2005年济南CINRAD／SA雷达资料，统计分析了基于网格的对流云的垂直累积液态含水量（VIL）分布特征，同时对VIL密度（VILD）及0℃层以上的VIL值（VILH）也进行了分析，结果表明，冰雹云和非降雹对流云的VIL、VILD和VILH值有明显差异。降雹单体特别是强降雹单体在成熟前期有明显的VIL跃增现象，强降雹单体的VIL跃增量达15．4kg·m^-2。冰雹云的最大VIL、VILD和VILH平均值比非降雹对流云的最大平均值分别高出20kg·m^-2、1．7g·m^-3。和16kg·m^-2。不同月份的VIL、VILD、VILH阈值对冰雹特别是大冰雹的识别具有很好的指示意义。基本上是在VIL达到最大值后开始降雹，5～7月3个月降雹单体的降雹时间分别滞后于VIL跃增后的体扫时间约4．8、11．4和12．3min。

Using the Jinan--CINRAD/SA data in 2002--2005, the distributive characteristics of Grid Vertically Integrated Liquid （VIL）, the VIL Density（VILD） and the VIL above the 0℃ layer（VILH） in the cases of convective cloud are analyzed. It is pointed out that the difference of VIL, VILD and VILH are obvious, the hail shooting had significantly higher grid VIL, VILD and VILH values on the average, through the entire time series when compared to the non-hailstorms. The maximum average values of Grid VIL, VILD and VILH of hailstorms is higher than the non-hail shooting, they are 20 kg · m^-2, 1.7 g · m^-3and 16 kg · m^-1 respectively. Grid VIL values for hail shooting have obvious phenomenon of increasing abruptly in the late stage of storm developing, such as the increasing magnitude was 15.4 kg · m^-2 for severe hail shooting. The hail shooting almost began after the VIL peak, so VIL peak used as a severe weather predictor has limited lead time. The average lead time was decided by the amount of time from the VIL increasing abruptly VCP end to the VIL peak VCP end . The average lead time in May, June and July was 4.8, 11.4 and 12.3 minutes, respectively. TS, PO and FAR were calculated for some parameters to determine the best possible points for which a warning or no warning decision can be based. The VIL,VILD and VILH thresholds in different months were examined for usable signals as warning hails. The VILH thresholds in May, the VILD thresholds in June, and the VIL thresholds in July have the best effect on warning hails.