African mineral dust sources: a combined analysis based on 3D dust aerosols distributions, winds and surface parameters

Abstract. Mineral dust aerosols are a key player in the climate system. Their emissions are not yet characterised enough to ensure their good representation in climate models. The work presented here aims at a better characterisation of dust sources by a new analysis method. We use the three-dimensional dust aerosols distribution from the Infrared Atmospheric Sounding Interferometer (IASI), obtained with the Mineral Aerosols Profiling from Infrared Radiances (MAPIR) algorithm. The availability of vertical information on top of total column information allows to better separate emissions from transport. However, the presence of dust at the surface could also be due to low altitude transport, or to deposition processes. Therefore, to strengthen the analysis, we have completed it with an analysis of wind speed and surface state parameters (land cover, vegetation, moisture). For the more complex case of the Sahel, we have also analysed the soil type and the wind direction patterns. Our analysis highlights the well-known Saharan hot-spots, but also a less well-known significant emission place west of the Bodélé depression. The study of Sahel dust sources is a new feature for satellite-based analyses. Our results are coherent with those drawn from local ground-based measurements, allowing to extend our analysis to the entire Sahel area with confidence. We also provide a morning versus evening comparison, helping to distinguish the different emission mechanisms in play, and a small year-to-year variation analysis.