Spatial variation of the aerosol concentration and deposition over the Mediterranean coastal zone

A model for the spatial variation of aerosol concentrations and deposition along the coastal zone is of great interest for studies on air and water quality. In coastal areas, sea-spray aerosols generated at the sea surface by the interaction between wind and waves add to a continental contribution emitted from natural and/or anthropogenic sources. To include coastal effects in the model for the prediction of aerosol concentrations, Piazzola et al. (2003) developed the coastal Mediterranean aerosol model. The present paper deals with an extension of the Mediterranean coastal aerosol to a regional scale applied to the prediction of the sea surface flux deposition. This was achieved by the development of an automatic coupling process between the aerosol model and a regional meso-scale meteorological model which allows accounting for the details of the orography of the coast. The results show a non-homogeneous spatial coverage of aerosol concentrations over the northwestern Mediterranean. The simulations were then validated using aerosol size distributions recorded on board the ship “Atalante” for two kinds of meteorological conditions. Error calculations show a good performance of the coupling process since it predicts the aerosol concentration to within a maximum factor of 3 for particle radii between 0.1 to 10 µm. This process was then used to provide the spatial distribution of the particle deposition fluxes over the study area.