Mineral dust effects on clouds and rainfall in the West African Sahel

Abstract

Abstract. Aerosol cloud interactions are known to be of great importance to many parts of the climate system. Five years of observations from three different satellites (NASA EOS Aqua, Meteosat Second Generation and the Tropical Rainfall Measuring Mission) are used to statistically analyse the influence of mineral dust aerosol, separated from other aerosol species, on monsoon season cloudiness and precipitation in the West African Sahel domain. The aerosol-cloud-interactions were analysed separately by season and flow (air mass) in order to exclude spurious correlations with meteorological conditions. As expected from theory and previous case studies a reduction of precipitation due to reduced droplet sizes and suppression of convective activity under the influence of dust aerosol is evident from the analysis of this multiple year dataset. These results thus support the theory of a positive desertification feedback loop of mineral dust aerosol from a large-scale dataset.