Aerosol variability and weather regimes over the mediterranean region

Abstract

The Mediterranean region is characterized by the accumulation of aerosols from numerous and various sources, which show a strong spatio–temporal variability and a resulting large variety in aerosol optical properties over this basin. This study realized in the framework of the ChArMEx initiative aims at explaining this aerosol variability and the relationship between aerosol loads and weather conditions. From a regional simulation carried out with the ALADIN-climate model including an interactive aerosol scheme for the main species present in this region (desert dust, sea-salt, sulfates and carbonaceous particles), we have identified typical synoptic conditions that favour high aerosol loads over the Mediterranean, or on the contrary that are opposed to these high aerosol loads. These weather regimes are based on a statistical method of automated classification. This method enables to characterize the effects of aerosols on climate for each weather regime, and the links between aerosol variability and climate oscillations such as the North-Atlantic Oscillation (NAO).