大气气溶胶对混合相对流云影响的模拟研究

Numerical Study on Effects of Aerosols on Mixed-phase Convective Clouds

利用二维面对称分档云模式,讨论了气溶胶类型及浓度对混合相对流云及其降水的影响。结果表明:海洋性气溶胶谱分布在一定程度上更有利于降水的形成,随着气溶胶浓度的增加,尤其是在污染大陆性云中,暖云和冷云降水量均大幅减少。海洋性云中的大粒子和较高的过饱和度,加速了暖雨的碰撞过程和冰粒子的凝华增长;初始气溶胶浓度的增加最显著的效应是云滴数浓度和云水含量增加,云滴有效半径减小,云滴的冷却蒸发抑制对流的发展。

The influences of the aerosol type and concentration on mixed-phase convective clouds were investigated using a two-dimensional spectral resolving cloud model. The results showed that the distribution of maritime aerosol spectrum was more conducive to the formation of precipitation to some extent. With increasing aerosol, especially in the polluted continental cloud, the amount of precipitation in both warm and cold clouds were significant reductions. The maritime cloud had the larger droplet sizes and higher supersaturation, which enhanced drops growth by collisions and ice processes by deposition growth, respectively. The most noticeable effects of increasing aerosol concentrations were the increases of the cloud droplet number concentration and liquid water content but a decrease in the effective droplet radius, the evaporation and cooling of cloud droplets inhibited the development of convection.