Diagnosis of Transboundary Mass Fluxes from Modelled North American Regional Sulphur and Nitrogen Deposition Fields

Vet and Ro (Atmos Environ 42:2518–2529, 2008) developed an observation-based acid deposition model consisting of a conceptual regional mass-balance framework and inputs of mean area-integrated emissions data and wet deposition measurements over eastern North America. They then applied this model to estimate multi-year transboundary mass fluxes of sulphur and oxidized nitrogen between eastern Canada and the eastern United States during the 1990s. In this paper their approach is extended to use gridded emissions and deposition fields obtained from a numerical acid deposition model as inputs in place of measurements in order to diagnose transboundary fluxes of sulphur, oxidized nitrogen, and reduced nitrogen from model-predicted annual wet, dry, and total deposition fields. By following this approach, additional information of interest can also be inferred from an acid deposition model simulation after the simulation has been completed.