International audienceAn off-line global three-dimensional tracer model based on analyzed wind fields was augmented to simulate the atmospheric transport of mineral dust. The model describes the evolution of the aerosol size distribution and hence allows to compute aerosol number and mass concentrations. In this study we describe the parameterization of the sedimentation process and include a preliminary source formulation but exclude wet deposition. Validation of the model is done during a 16-day period in June-July 1988 with very scarce precipitation. It is based on a comparison of every model grid box with daily satellite-derived optical thickness observations of Saharan dust plumes over the North Atlantic and the Mediterranean. The mode...