重庆地区夏季一次降水过程及增雨潜力的数值模拟分析

Numerical Simulation Analysis of Rainfall Characteristics and Artificial Precipitation Potentiality in a Summer Precipitation Process of Chongqing

利用国家气象中心GRAPES人工增雨云系模式,选取2008年7月4日重庆地区一次降水过程进行数值模拟,分析了重庆地区降雨天气的水汽分布、云系宏微观分布、云中微物理转化和增雨潜力等特征。结果表明:本次降水大气过程中,重庆地区水汽含量极为丰富,水汽分布与地形分布呈明显的对应关系,低层水汽输送较大,整层水汽通量较高,有明显水汽辐合,云中液态水对地面降水影响很大。西南气流和地形共同作用为重庆地区液态水的形成提供了有利条件,在东北部山区迎风坡处大量水汽累积抬升,易形成丰富的液态水。重庆东北部地区水汽向云水转化较强,过冷液态水含量丰富,冰晶含量少,0℃层附近水汽垂直通量较大,降水效率较低,有较大的增雨潜力。

By using the GRAPES artificial precipitation model,a precipitation process on July 4,2008 in Chongqing is simulated,and the characteristics of vapor distribution,cloud microstructure,microphysical conversion and artificial potential are analyzed,the results show that;in this precipitation process,the water vapor is extremely rich in Chongqing,and the vapor distribution is corresponding to the topographic distribution.Meanwhile,the low-level water vapor transport is large,the whole layer of water vapor flux is relatively high;with a moisture convergence,the cloud liquid water has a great impact on ground rainfall. Southwest air flow and terrain together provide favorable conditions for the formation of liquid water in Chongqing.There is a large amount of water vapor accumulated in the windward slope of northeastern mountain area,and easy to form a wealth of liquid water.In this precipitation process,a plenty of water vapor converted into cloud water in northeast of Chongqing,then it is rich in supercool liquid water,less in ice number,low in precipitation efficiency,and the vapor vertical flux is large at 0℃layer,therefore it has greater potential for precipitation enhancement.