人工缓减梅雨锋暴雨的数值试验  

Numerical Experiments on Artificial Seeding of Decreasing the Meiyu Heavy Rainfall

作　　者：孙晶[1] 史月琴[1] 楼小凤[1] 胡志晋[1] 

机构地区：[1]中国气象科学研究院,北京100081

出　　处：《大气科学》2010年第2期337-350,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目40805003;国家自然科学基金资助项目40305001;国家自然科学基金资助项目40705002;"十一五"国家科技支撑项目2006BAC12B01

摘　　要：本文利用耦合了中国气象科学研究院双参数微物理方案的中尺度数值模式MM5,对2002年7月22～23日长江中游一次梅雨锋暴雨过程进行了人工缓减暴雨的冷云催化数值试验。在对降水云系多尺度结构进行正确模拟的基础上,采用增加人工冰晶的催化方法,对人工缓减暴雨的可能方法及原理进行研究。结果表明,不同催化方案得到比较稳定一致的结果,在云体成熟期大剂量持续催化的减雨效果最好,在3600km2内减少雨量8.29×106t,即为自然雨量的14.8%,雨量分布更为均匀,其中50mm以上降水范围由原来的190km2缩减到60km2。分析表明,催化增加的大量冰晶碰并过冷雨,使霰粒子浓度增大而平均尺度减小,导致霰落速减弱而小于上升运动,难于下落融化,造成雨水减小。在周围升速小的弱雨区,滞留的霰粒长大后仍能下落融化,引起地面少量增雨。本文所用催化方法在实际作业中具有技术可行性,并有重大潜在社会和经济效益,值得深入研究和试验。A case of heavy rainfall during the Meiyu period of 22-23 July 2002 is simulated using mesoscale model MM5 coupled with the CAMS（Chinese Academy of Meteorological Sciences）microphysical scheme.Numerical experiments of adding ice crystals are conducted to study if there is any possibility to decrease the heavy rainfall.Several tests for different seeding times and different concentrations of seeding particles are designed.Results show that overseeding in the mature stage results in the most reduction of rainfall.In the region of 3600 km^2,rainfall is decreased by 14.8%,which is 8.29×10^6 t.The heavy rainfall area with precipitation over 50 mm decreases from 190 km^2 to 60 km^2.After seeding with a large amount of ice crystals,graupel grows through the collection of ice crystal with supercooled rain water.This causes that the number concentration of graupel becomes larger and the mean diameter of graupel becomes smaller.The falling speed of graupel becomes smaller than the updraft and graupel cannot fall to the warm region to melt.This is one of the main reasons of decreasing surface rainfall.While in the weak updraft region around the decreasing rainfall center,graupel retained in the cold area grows gradually,and then falls,which increases the rainfall in the weak precipitation region.The overseeding methods in this paper are able to be used technically in the practical field test,which is worthy to make further studies and tests.

关 键 词：梅雨锋暴雨 人工减雨 数值模拟 

分 类 号：P426[天文地球—大气科学及气象学]