The Sahara and Sahel regions of Africa are important sources of dust particles into the atmosphere. Dust particles from these regions are transported over the Atlantic Ocean to the Eastern American Coasts. This transportation shows temporal and spatial variability and often reaches its peak during the boreal summer (June-July-August). The regional climate model (RegCM 4.0), containing a module of dust emission, transport, and deposition processes, is used in this study. Saharan and Sahelian dusts emissions, transports, and climatic impact on precipitations during the spring (March-April-May) and summer (June-July-August) were studied using this model. The results showed that the simulation were coherent with observations made by the MISR satellite and the AERONET ground stations, within the domain of Africa (Banizoumba, Cinzana, and M’Bour) and Ragged-point (Barbados Islands). The transport of dust particles was predominantly from North-East to South-West over the studied period (2005–2010). The seasonality of dust plumes’ trajectories was influenced by the altitudes reached by dusts in the troposphere. The impact of dusts on climate consisted of a cooling effect both during the boreal summer and spring over West Africa (except Southern-Guinea and Northern-Liberia), Central Africa, South-America, and Caribbean where increased precipitations were observed. 1. Introduction Numerous studies have been focused on Sahelian climate variability contrary to the tropical humid African areas for which reliable data do not exist. Servat et al. [1] showed that the tropical humid belt has been similarly affected by series of climatic episodes in comparison with those observed in the Sahelian zone. In addition, this region has been subjected to significant environmental changes due to the increase of populations and strong exploitation of natural resources such as deforestation [2]. Furthermore, this region is particularly rich in aerosols from various origins leading to coexistence in the region of maritime, desert, urban, and bushfire aerosols. Besides, the plumes of desert and Sahelian dusts ejected into the atmosphere during emission episodes are an integral part of the West African climate system [3–5]. The greater part of mineral aerosols is emitted from arid and semiarid zones on the Earth where, these surfaces are less protected from erosion because of very limited or inexistent vegetative covers, and of very low soil humidity limiting the cohesion of constituent elements [5]. Thus, the Saharan-Sahelian region has been identified as the world’s first source of
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