旬邑冰雹云的数值模拟及累积带特征

在中国科学院大气物理研究所三维完全弹性冰雹云模式的基础上,把雨滴冻结过程作了进一步改进,增加了雨滴冻结成霰的过程.并利用改进后的模式模拟了陕西省旬邑县1999年7月17日的冰雹云个例,发现该例雹云中冰雹胚胎主要是冻滴,在雹云发展的初期阶段雹云中存在过冷雨水累积带,并且该处是雹胚产生的主要区域,雹块的增长主要通过雹与云水的碰并过程增长.对旬邑县1997～1999年14例冰雹云过程的模拟结果表明,旬邑冰雹云中冰雹胚胎以冻滴为主,绝大多数冰雹云都存在过冷雨水累积带,累积带维持时间约6 min,厚度4 km左右.

Numerical Simulation of Hailstorms and the Characteristics of Accumulation Zone of Supercooled Raindrops

On the basis of an IAP 3\|D hailstorm numerical model, the process of raindrops freezing was improved. Using the improved model, a hailstorm occurred in Xunyi County, Shaanxi Province in northwest China on July 17, 1999 and other 14 hailstorms were simulated. The results show that the most of the hailstorms in Xunyi County exist accumulation zones of supercooled raindrops and the hail embryos are mainly frozen drops. The present of accumulation zone of supercooled raindrops lasts about 6 minutes and with the thickness of 4 km about. And the accumulation zone is also the area of hail embryo formation. The hailstones grow through hailstones collection cloud water in the hailstorm occurred on July 17,1999.