Meteorological variability of the wet and dry deposition of sulphur and nitrogen compounds over the Baltic Sea

The dry and wet deposition of N and S compounds to the Baltic Sea Basin were assessed using daily concentration measurements of air and precipitation concentrations, and actual meteorological data on precipitation, daily wind speed and wind direction, as well as the buoyant fluxes at the air-sea interface. The data cover the period 1980-86. Both concentrations and deposition levels show distinct south-north gradients and strong seasonal variability. Dry deposition is an important contribution in the case of S (25 to 80%) but is less significant for the N compounds (10 to 30%). The contribution of particles to dry deposition is negligible for S, equivalent to the gaseous contribution for oxidized N and about 10 to 20% for reduced nitrogen compounds. The obtained total annual deposition of about 1.4 to 1.8 g(S) m super(-2) for the S compounds, and 1 g(N) m super(-2) for the N compounds are comparable with, but on the upper side of, previous empirical and model estimates.