Modelling and assessment of acidifying and eutrophying atmospheric deposition to terrestrial ecosystems. PINETI-4

Biodiversity in Europe is strongly affected by atmospheric nitrogen and acid deposition to ecosystems. We present new quantitative estimates of the deposition of atmospheric nitrogen (N) and sulfur compounds to terrestrial ecosystems across Germany for the years 2000, 2005, 2010 and 2015 till 2019. On average, the nitrogen deposition in Germany has decreased from more than 19.5 kg N ha-1 yr-1 to about 14 kg N ha-1 yr-1 (which is from ~1400 eq ha-1 yr-1 to 1000 eq ha-1 yr-1). The total deposition mapping combines three approaches: 1) chemistry transport modelling for the dry deposition, 2) geostatistical interpolation of observations for the wet deposition, and 3) a simple estimate for the occult deposition. To improve the assessment compared to earlier estimates from PINETI-3 the LOTOS-EUROS modelling was improved by including the latest information on emissions (most notably for the agricultural sector), by incorporation of dynamic emission time profiles and by increasing the horizontal (2x2 km2) and vertical model resolutions. These implementations lead to better evaluation scores in comparison to observations and result, on average, in an approximately 10 % increased nitrogen deposition estimates compared to the PINETI-3 report. The latter is mainly driven by larger modelled fluxes for dry deposition, as a result of the updates in the emission information and the model’s vertical resolution. We also provide model-based estimates of the origin of N-deposition in each of the federal states for the year 2019. The importance of long-range transport is illustrated by the result that for all states more than 50 % of the N deposition was calculated to originate from emissions outside the state. Sensitivity simulations for surface and stack emissions of ammonia showed that within a distance of 20 km around the source about 20 % and 5 % of the total emission is deposited, respectively.