Interaction of Aerosol Particles and Clouds

Abstract

With the spectral scavenging and microphysics model DESCAM coupled to a 2D dynamic framework the transport and scavenging of aerosol particles by a medium-sized convective cloud are investigated. For typical marine conditions the author has found a depletion of the marine boundary layer of about 70%. Also, about 70% of the vented up aerosol particle mass entered cloud drops due to nucleation. For these simulations the author found an increase in relative humidity, as well as number concentration of Aitken and large and giant particles near cloud top. The increase in relative humidity and large and giant particle concentration was coupled to cloud outflow regions, while the increase in Aitken particles can be attributed to lifting of free tropospheric air due to cloud-top rising. Sensitivity tests varying the number of free tropospheric sulfate particles changed the number of cloud drops but had little effect on precipitation formation and evolution.