A new Saharan dust source activation frequency map derived from MSG-SEVIRI IR-channels

We present a new dust source area map for the Sahara and Sahel region, derived from the spatiotemporal variability of composite images of Meteosat Second Generation (MSG) using the 8.7, 10.8 and 12.0 mm wavelength channels for March 2006-February 2007. Detected dust events have been compared to measured aerosol optical thickness (AOT) and horizontal visibility observations. Furthermore the monthly source area map has been compared with the Ozone Monitoring Instrument aerosol index (AI). A spatial shift of the derived frequency patterns and the local maxima of AI-values can be explained by wind-transport of airborne dust implicitly included in the AI signal. To illustrate the sensitivity of a regional model using the new dust source mask, we present a case study analysis that shows an improvement in reproducing aerosol optical thickness in comparison to the original dust source parameterization.