Aerosol modeling over Europe: 1. Interannual variability of aerosol distribution

[1] Aerosol distribution over Europe has been simulated with a regional atmosphere-chemistry model. Primary and secondary organic and inorganic aerosols have been considered. The simulation was conducted for two different meteorological years 2002 and 2003 to analyze the spatial and temporal variability of the aerosol distribution. This paper focuses on the aerosol distribution, while the corresponding radiative forcing is described in the accompanying paper. Meteorological conditions play a major role in spatial and temporal variability in the European aerosol burden distribution. Regionally, year to year variability of monthly mean aerosol burden can reach up to 100% because of different weather conditions. The model evaluation against the source apportionment analysis shows that aerosols from fossil fuel combustion are well simulated. The evaluation suggests the importance of biomass burning emissions, which are not considered in the model simulations presented here. Because of lack of these emission sources and because of additional unknown formation processes of secondary organic aerosol, the carbonaceous aerosols are underestimated by a factor of 2-5 for black carbon and 10 for the organic carbon, respectively. Modeled sulfate aerosol is well represented.