Abstract:

Based on the CPAS system, the characteristic parameters such as echo intensity, vertical liquid water content (VIL), height of 45 dBZ radar echo top, echo bottom and strong echo center for 26 hail cases in Anshun of Guizhou Province during 2009-2015 were analyzed. Combined with the height of 0 ℃ and -20 ℃ layers in Guiyang radiosonde station, the identification indicators of hail cloud in Anshun city were synthetically summarized. The results show that the hail weather processes occurred from March to June during 2009-2015 in Anshun of Guizhou Province, and the frequency of hail occurrence was the most in April and the least in June. The maximum echo intensity of most hail clouds in Anshun city was 45 dBZ and above before the falling of hail, and the value of VIL in March and April was more than 15 kg·m-2, while that in May and June was greater than 25 kg·m-2. The average height of 0 ℃ and-20 ℃ layers on the day of the hailfall gradually increased from March to June, and the latter was 3.11 km higher than the former. The height of 45 dBZ strong echo of hail clouds was greater than 8 km, the height difference between strong echo center and 0 ℃ layer was greater than 0 km, and that between 45 dBZ strong echo top and 0 ℃, -20 ℃ layers were greater than 2.3 km and 0.2 km, respectively, which could be taken as indictors for identification of the hail clouds. The early warning indictors could effectively guide the hail suppression operation by applying for a case.

Key words:  Anshun of Guizhou Province, hail, characteristic parameter, recognition index

摘要：

利用2009—2015年贵州安顺市26个冰雹个例资料，基于CPAS系统统计分析了冰雹个例的回波强度、垂直累积液态水含量、45 dBZ强回波顶高及强回波中心高度等特征参数及其时间变化，并结合探空站0 ℃层和-20 ℃层高度，综合归纳了安顺市冰雹云的识别指标。结果表明：近7 a来，安顺市冰雹天气发生在3—6月，4月最多，6月最少；降雹前最大回波强度多在45 dBZ及以上，3月和4月的VILmax≥15 kg·m-2， 5月和6月VILmax≥25 kg·m-2；降雹日的0 ℃层和-20 ℃层平均高度均呈逐月增加趋势，-20 ℃层平均高度比0 ℃层高3.11 km；45 dBZ强回波顶高在8 km以上，且与0 ℃、-20 ℃层高度差分别大于2.3 km、 0.2 km，强回波中心高度与0 ℃层的高度差大于0 km可作为该市冰雹预警指标。通过个例应用，冰雹预警指标能够有效指导防雹作业。

关键词: 安顺市, 冰雹, 特征参数, 识别指标