Mapping dry deposition of acidifying components and base cations on a small scale in Germany

Dry deposition fields, which are calculated for 1989 and 1993 using the EDACS-model (European Deposition of Acidifying Components on a Small scale), clearly reflect the spatial detailed land use information and the large-scale concentration and climate patterns over Germany. Dry deposition of potential acid (SO_x+NO_y+NH_x) was highest in eastern Germany and lowest in southern Germany. Dry deposition of non-sea salt Mg₂⁺ plus Ca₂⁺ plus K⁺ was highest in eastern and southeastern Germany and lowest in northwestern Germany. Dry deposition fluxes on forest were higher than the average dry deposition fluxes on Germany: ca. 40% for the acidifying components and 25% for the base cations. The relative contribution of SO_x, NOy and NH_x to the dry deposition of potential was ca. 75%, 15% and 10% respectively, both for Germany in general and forests. Dry deposition of SOx, NOy, NHx and potential acid in 1989 was higher than in 1993: by 24%, 16%, 12% and 22%, respectively.

The percentage of the total (wet+dry) deposition of potential acid which is counteracted by total deposition of non-sea salt Mg²₊ plus Ca²₊ plus K⁺ was largest (20-30% on average) in northeastern and southern Germany. EDACS model estimates were compared with throughfall estimates. Generally they compared reasonably well taking into account the relatively large uncertainty in both estimates. On average no significant differences were found.