Influence of Grid Resolution and Biomass Burning Emissions on Air Quality Simulations: A Sensitivity Study with the Modelling System COSMO-MUSCAT

Model evaluation studies are essential for determining model performance as well as assessing model deficiencies, and are the focus of the Air Quality Model Evaluation International Initiative (AQMEII). The chemistry-transport model system COSMO-MUSCAT participates in this initiative. In this paper the robustness and variability of the model results against changes in the model setup are analyzed. Special focus is given to the formation of secondary particulate matter and the ability to reproduce unusually high levels of PM10 in Central Europe caused by long-range transported smoke of widespread agricultural burning and forest fires in western Russia. Seven different model configurations are investigated in this study. The COSMO-MUSCAT results are evaluated in comparison with ground-base measurements in Central Europe. The analysis is performed for two selected periods in April/May and October 2006 which are characterized by elevated concentrations of PM. The model sensitivity is studied against changes in the used grid resolution, the meteorological forcing and the applied aerosol module. Possible reasons for differences in model results will be discussed.