2002年7月沈阳一次降水过程的催化数值模拟研究

AgI-Seeding Modeling Study on the 12 July 2002 Cold Vortex Precipitation in Shenyang

应用三维对流云模式和探空资料,对沈阳地区2002年7月12日发生的一次东北冷涡降水过程进行了数值模拟研究。结果表明,这次降水主要是由积层混合云引起的,其中冰相过程占主导地位,霰的融化是最主要的雨生成项。催化模拟试验表明,当云体处于成熟稳定的积层混合云阶段,在0℃层高度以上播撒AgI能起到显著的增雨效果。积层混合云具有巨大的人工增雨潜力。

In 12-15 July 2002 ,the eastern of Liaoning Province was hit by cold vortex precipitation and hails. In order to analyze the cloud microphysical processes, we used a three-dimensional convective cloud model developed by IAP to simulate this event. According to simulations, the cloud system which produced the precipitation was the convective-stratiform mixed clouds. The mechanisms of ice particles melting played a main role in cloud and precipitation formation, especially graupels melting accounted for about 50 % of total rainwater production. Through a series of the modeling calculations of AgI-seeding, we found that the optimal time of AgI-seeding cloud was at the cloud mature stage and the seeding height should be above the 0 ℃ layer. Simulations also show that the convective-stratiform mixed clouds have a considerably seeding potential to enhance precipitation.