The Effect of Vertical Turbulent Fluctuations in the Atmosphere on the Collection of Aerosol Particles by Cloud Drops

Abstract

A one-dimensional model of the effect of the vertical component of atmospheric turbulent fluctuations on the collection of micron-size aerosol particles by cloud drops is presented. The model includes simultaneous effects of the differential inertial response of the drop and particle to turbulent accelerations and the hydrodynamics of air flowing around the drop. Based on the one-dimensional results, it is inferred that three-dimensional atmospheric turbulence should cause a substantial increase in the collection of particles in the approximate radius range of 0.5 to 2.5 ?m, and that this increase should be most prominent for cloud drops in the neighborhood of 30 to 40 ?m radius. Also discussed am the expected effects of turbulence on related cloud microphysical processes, including the collection of small droplets by large drops in atmospheric clouds, the collection of submicron particulates and pollutant gases by cloud drops, and the evaporation of cloud drops in subsaturated air.