Diffusion Process of Aerosol Particles with Different Diameter over Complex Terrain

Abstract

Properties of the aerosol particle (AP) is important to understanding the formation of fog-haze, and even for the evolution of climate. Based on the mesoscale large-eddy simulation model of ARPS and with the consideration of gravitation deposition (GD), the diffusion process of AP with three diameters of 10ï­m, 50ï­m and 100ï­m over complex terrain are investigated. Simulation results show that the diffusion of AP with different diameter exist differences and universality. For the AP with smaller diameter of 10ï­m, the diffusion range along stream direction and height is very large due to the stronger fluid following and the slight GD properties. While for the AP medium diameter of 50ï­m, the diffusion range along stream direction decreases rapidly but less changed along height. Under the strongly GD effect, the diffusion range of AP with diameter of 100ï­m along two direction is very small. For all AP with different diameter, the diffusion height trends to a steady state and exist a “overshoot†phenomenon obviously.