Desert Aerosol in the Mediterranean

Tropospheric aerosols may affect climate through different mechanisms. In particular, aerosols intervene in the water cycle, and may influence the hydrologic balance. In the Mediterranean a large role is played by desert dust originating in the Sahara. Mineral dust production depends on soil aridity, i.e., among other factors, on land use, and precipitation/temperature regimes. In the Mediterranean, desert dust is mostly transported northward during spring and summer, driven by low and high pressure systems over north Africa. In addition, depending on the synoptic situation, anthropogenic particles and marine aerosols are found over the Mediterranean. The Mediterranean basin is thus an excellent laboratory to study the complex interactions of different type of particles with the radiative field, the hydrological cycle, and clouds. Some results of measurements carried out at Lampedusa island (35.5°N, 12.6°E) in 1999, showing the presence of desert dust and its effects on the radiative field, are described.