ORIGINS OF AFRICAN DUST TRANSPORTED OVER THE NORTHEASTERN TROPICAL ATLANTIC

On the basis of 3 years of daily measurements of mineral dust concentr ations at Sal Island (Cape Verde), this study focuses on the origin of the dust transported over the northeastern tropical Atlantic during t he dusty season (October to April). Using backward trajectories, we ha ve identified three different sectors of origin of the transported dus t, covering the Sahara (north/west and central/south) and the Sahel re gions. Time variations of the dust transport from these different area s can be explained by the seasonal shift of the subtropical high-press ure center. A geochemical approach highlights that the calcium amount and the Si/Al ratio of the transported dust differ according to these source regions, in relation to their respective soil compositions.