Predominant transport paths of Saharan dust over the Mediterranean Sea to Europe

We use monthly data of aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the 7 NASA Terra and Aqua satellites for the ten-year period (2001 -2010) in order to determine seasonal variations of Saharan dust transport over the Mediterranean towards Europe. The maxima of AOT are used to visualize the transport paths. Saharan dust reaches Europe over the Mediterranean, and also by looping back over the Atlantic. In spring, aerosols are observed within a wide range of longitudes in Europe, with the highest AOT over West Europe. This may be partially explained by dust transport to Western Europe via the Atlantic route, while to Central and Eastern Europe dust is transported over the Mediterranean. During all seasons dust is transported over the Mediterranean to Europe. In the summer months, aerosols are observed predominantly in Central Europe. In autumn, aerosol activity is strongest in Eastern Europe. We show that there are local AOT maxima over North Italy, in the Alps, in Spain, South-East of the Pyrenees and Sierra Nevada, and in the Rila Mountains in Bulgaria. We suggest that these maxima of aerosol concentration appear as the dustcarrying air flow reaches the mountains and slows.