一次防雹作业过程的效果分析

利用2008年5月23—26日山东一次冰雹过程的常规气象资料，分析了此次冰雹形成的天气形势、层结条件及其触发机制等；分析了两个极相似云体在催化和未催化情况下从初生、发展到消亡的演变特征。结果表明，防雹作业加剧了冰雹云的消亡过程，表现为回波强度减弱、回波高度下降、VIL减小、生命史缩短等特征。通过对对流云系的横向和纵向对比分析，收集了18个防雹作业样本，并利用这些样本作业前后的回波强度和回波高度两个物理量进行统计检验，在显著性水平分别为1%和5%的情况下，防雹作业后回波强度减弱、回波高度下降，即防雹作业有效。利用济南防雹作业数据对防雹作业效果进行的模拟定量检验表明，防雹作业可减少降雹约27%。

Effect analysis of a hail suppression operation in Shandong

The conventional meteorological data of a hail process happened in Shandong from 23 to 26 May 2008 are used to analyze the synoptic situation, stratification conditions, trigger mechanism of the hail process, and the evolution characteristics of two very similar clouds from primary state to disappearance under catalysis and non catalysis. It indicates that the hail cloud is intensified to disappear by the hail suppression operation, which is manifested as weakened echo intensity, reduced echo height, decreased VIL and shortened duration. The contrastive analysis of convective clouds in horizontal and longitudinal direction helps to collect 18 samples of hail suppression operation, whose echo intensity and echo height before and after the operation are used to do statistical test. It is found that when the significance level reaches 0.01 and 0.05, the echo intensity is weakened and the top height goes down, and the effect of hail suppression operation is obvious. By using the three dimensional hail cloud numerical model and the seeding amounts, the effect of hail suppression operation is studied, and the hail suppression operation can reduce the hail of about 27%.