一次对流过程对气溶胶清除和再生过程的影响

利用中尺度天气预报和研究模式(WRF)对2007年4月23～24日广东省发生的一次飑线过程进行了模拟,研究了水凝物粒子对气溶胶的清除过程、液滴蒸发引起的气溶胶再生过程以及动力输送作用对气溶胶数浓度的影响.结果表明,降水与近地层气溶胶数浓度的变化呈负相关关系.综合对比各水凝物种类的碰撞清除率和核化清除率,发现云滴核化过程...

The impacts of convection on aerosols scavenging and regeneration processes

A squall line occurred during April 23~24, 2007 over Guangdong province, China has been simulated by using the Weather Research and Forecasting (WRF) model in order to investigate the impaction scavenging of aerosol particles by hydrometeors, aerosol regeneration due to complete evaporation of liquid drops, and effects of dynamical transport on the number concentration of aerosols. The results showed that there was a negative correlation between the precipitation and aerosol concentration near surface. By comparing the impaction scavenging rates by different types of hydrometeors and nucleation scavenging rates, it showed that droplet nucleation contributed most to the aerosol scavenging, followed by the impaction scavenging by rain drops at the lower troposphere and snow at the upper troposphere. Droplet nucleation scavenging and ice crystal nucleation scavenging were the dominant scavenging processes for hygroscopic and non-hygroscopic particles respectively. The variation of aerosol number concentration was the result of combined effects of cloud dynamical transport, wet scavenging and regeneration process due to the evaporation of liquid drops. The regeneration process mainly occurred from the surface to the 10km altitude. During the development of convection, the aerosol concentration near surface was significantly reduced whereas the heavy pollution area appeared around the non-precipitation area near the gust front due to the dynamical transport. At the upper troposphere, the number concentration of hygroscopic particles was reduced while that of non-hygroscopic particles was increased.