Impacts of meteorological situations and chemical reactions on daily dry deposition of nitrogen into the southern North Sea

The impact of the meteorological situation and chemistry on dry deposition to the southern North Sea is investigated. The studies are performed using a high-resolution meteorology/chemistry model system of different complexity for a five-day period in June 1998. The simulations consider passive tracer transport (Case I), gas phase chemistry (Case II), gas phase plus simple aerosol chemistry (Case III), gas phase plus size dependent aerosol chemistry (Case IV). The results show a very good agreement of meteorology model results with measured data and a reasonable agreement for the concentrations. The dry deposition to the southern North Sea differs a factor of three to seven within the investigated five-day period. Differences are larger for a more complex chemistry. The average dry deposition increases by a factor of three when including gas phase reactions or adding a simple aerosol model and up to a factor of eleven when considering a sectional aerosol model. The input composition depends on the chemistry considered.