两次华北冷涡过程雹云结构特征及AgI催化效果数值研究

用三维完全弹性非静力平衡雹云模式模拟了不同低涡雹云演变特征和人工引晶催化效果,结果表明:冷涡雹云中不存在大量的过冷雨滴,过冷水几乎是由云滴组成的,雹胚形成以云霰转化为主,由冰相过程形成降水粒子。近地面有薄逆温层云体,云底温度高,云中垂直运动强,云中过冷云水含量增长迅速且丰富。在雹云主要上升气流到达的过冷水含量大值区下方和过冷水大值区中心部位分别一次引进×107/kg碘化银粒子进行大剂量催化试验,碘化银主要以凝结-冻结方式核化成冰,雹胚浓度增加,雹胚过多争食抑制冰雹增长,使得冰雹直径明显减小。

NUMERICAL STUDY ON AgI SEEDING IN HAIL STORMS WITH VARIOUS COLD VORTEX PROCESS IN SHANDONG

The result of the numerical simulation of hailstorms in two cold vortex processes by using the three-dimensional elastic nonhydrostatic model showed that there were a lot of super-cooled cloud droplets instead of raindrops. The initiation of natural precipitation elements in the strong convective clouds was related with the ice phase .The hail embryos were formed mainly through conversion of cloud droplet to graupel. In thin ground inversion cloud, the cloud bottom temperature was higher, the vertical convection was stronger, the super-cooled water increased faster and the content was richer. After seeding AgI particles in the cloud in two different ways, ice-forming nuclei was produced in concreting-freezing way under the lower temperature clouds, reduced the super-cooled raindrops and suppressed hailstone growth by accretion, increased the number density of canisters, lighten the disaster of hailstone.