青海省秋季一次对流云人工增雨的数值模拟

利用中国气象科学研究院的三维对流云数值模式，模拟了青海省2002年秋季一次对流云过程，分析了青海省秋季对流云云体发展的动力学特点和微物理特征。数值模拟结果表明，青海省秋季的对流云降水几乎全部是由霰的融化形成的，而自然云中冰晶含量少、冰霰自动转化形成霰胚的过程非常微弱。但采用合适的方法催化以后，冰晶的核化、繁生量增加，通过冰霰自动转化过程形成大量霰胚，霰胚再通过其他冷云微物理过程迅速增长，融化成降水。催化后各种微物理机制都比催化前活跃，同时催化改变了云体的动力场分布，在动力过程和微物理过程的相互促进下，使增雨取得了很好的效果。

Numerical Simulation of a Convective Cloud Precipitation Enhancement in Qinghai in Autumn

With the 3D convective cloud model of CAMS, we simulate a convective cloud process in Qinghai in Autumn 2002, with emphases on dynamical and microphysical processes. Simulation results indicate that convective precipitation is almost all transformed by melting of graupels, but in unseeded clouds,the ice crystals amount is such rare that it contributes little to graupel formation. After seeding in proper position and time, the formation and ramification of ice crystals are enhanced. Automatic transformation from ice crystals to grauple contributes much to graupel embryoes. Almost all microphysical processes in seeded clouds are more active than those in unseeded clouds, and at the same time, the seeding changes the dynamical fields in the cloud in such a way that the inaction between dynamical and microphysical processes leads to precipitation enhancement.