中文摘要：

利用RAMS（Regional Atmospheric Modeling System）数值模式,研究了气溶胶数浓度的改变对半干旱地区春季出现的一次较大范围的降雹天气云微物理特性和降水过程的影响,模拟结果表明：（1）气溶胶对云中液态含水量垂直分布影响明显。气溶胶浓度改变使云中水成物的空间分布发生调整。（2）清洁大气环境的冰雹云中的冰雹形成主要是通过过冷雨水冻结,污染云中冰雹的形成主要来源于过冷雨水冻结和霰撞冻过冷云水的转换,而严重污染的云中冰雹则主要是通过霰撞冻过冷云水形成的。（3）气溶胶浓度增加时,地面累积降水量减少。（4）在污染云中冰相降水量最大,冰相降水对总降水的贡献随着污染加重而增加。（5）清洁云和污染云中降雹对冰相总降水的贡献起主要作用,而严重污染云中霰和雹对冰相总降水的贡献相当。（6）污染云中上升气流速度最大,但并不是气溶胶浓度越大,上升气流速度越大。

英文摘要：

The impact of aerosol on cloud microphysics and precipitation of spring hailstorm in semi-arid area is numerically simulated.Using the Regional Atmospheric Modeling System（RAMS） of Colorado State University.The results show that：（1） Aerosols have a great impact on vertical distribution of cloud liquid water content.The hydrometeor spatial distribution is affected by aerosol concentration.（2）The hail is mainly formed by supercooled rain water freezing in clean cloud;supercooled rain water freezing and graupel colliding with cold cloud water are important in hail formation of polluted cloud,and in serious polluted cloud the graupel colliding with cold cloud water plays a leading role of hail formation.（3） The increase of aerosol concentration leads to the decrease of accumulative precipitation.（4） Ice phase precipitation from polluted cloud（C2） is the highest.The contribution of ice-phase precipitation to the total precipitation has the same trend with the aerosol concentration.（5） Hail has the major contribution to the total ice-phase precipitation in the clean and polluted clouds（C1 and C2）,but hail and graupel both have great contribution to total ice-phase precipitation in the serious polluted cloud（C3）.（6） The vertical velocity is maximum in the polluted cloud（C2）,which means the increasing aerosol concentration strengthens of the hailstorm,but when the aerosol concentration is too high（C3）,the updraft will decrease.