Aeolian Dust Transport in West Africa

Abstract

Copied as is: Deep sea deposits of continental dusts are found in abundance off the coast of West Africa in the Atlantic Ocean, transported there in several periods of the geological past. The chemical properties of the deposited materials indicate the area of origin being south of the Sahara desert itself. This long distance dust transport from the continental areas to the oceanic deposition areas is closely connected to specific atmospheric flow systems. In summer the westward dust transport requires several components active in consecutive steps, these are taking the dust from the surface, bringing large enogh quantities high enough into the atmosphere and strong enough easterly winds. In an analysis of the synoptic scale flow systems of West Africa the rain bearing disturbances of the Sahel combine all these components and thus contribute to a large extent to the supply of dusts as they are found in the deep sea deposits as well as the supply of water vapour of the region allowing the formation of rain.