Mapping dry deposition of acidifying components and base cations on a small scale in Germany
Kartering van droge depositie van verzurende componenten en basische kationen in Duitsland met een hoge ruimtelijke resolutie
Leeuwen EP van , Draaijers GPJ , Jong PGH de , Erisman JW
RIVM Report 722108012
Results are presented of the research on 'Mapping dry deposition of acidifying components and base cations on a small scale in Germany'. Using these maps critical load exceedances can be calculated in more detail than could be achieved so far by using regional scale deposition estimates (e.g. from the EMEP model). 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 (SOx+NOy+NHx) 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 SOx, NOy and NHx 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.