A case study of mobilization and transport of Saharan dust

Abstract

Numerical models of the atmosphere and aerosols are used to investigate mobilization and transport of Saharan dust over West Africa and the tropical Atlantic Ocean for 23-28 August 1974. Mobilization was done by dry convective mixing of low-level jets associated with the easterly wave. The model simulations show that the aerosol at any one point can be a complicated mixture of particles lifted at different times and different places. Bimodal size distributions developed when dust was mobilized within a dust plume that was generated on a previous day. An elevated layer of dust developed over the ocean as the northeast trade winds advected clear air underneath the dust-laden air as it moved westward. The size and spatial distributions of aerosol in the marine layer depended upon the undercutting process, the amount of background mineral aerosol present, and transport across the marine layer inversion by sedimentation and turbulent mixing. -from Authors