The Generation, Turbulent Transfer and Deposition of the Sea-Salt Aerosol

Abstract

An atmospheric boundary layer (ABL) model is used to address problems involving the generation, turbulent transport, and deposition of giant sized (1?25 ?m) sea-salt aerosol. The surface aerosol generation rate is taken from the production flux expressions developed by Monahan. A simplified second-moment closure formulation for turbulent transport is used, while dry deposition fluxes are computed as functions of Stokes' settling speed and the rate of inertial impaction of particles across the viscous sublayer. Initially we investigate, starting from first principles, whether the model can develop reasonable sea-salt volume distributions at several different Beaufort wind forces Using the empirical expressions for generation and deposition fluxes, we permit an initially aerosol-free ABL to fill by diffusion until the volume distributions approach equilibrium., we then compare these distributions with the classic Woodcock observations. Further experiments are conducted in which we explore the dynamic behavior of the aerosol spectra when winds are varying, and also we study vertical sea-salt profiles in a humid, trade wind ABL.