This document establishes nitrogen deposition over Germany using modeling and observations from 2000-2015. It uses two modeling approaches - a chemistry transport model and an empirical approach using cloud water input - combined with observations of wet deposition and estimates of dry and occult deposition. The modeling shows nitrogen deposition in Germany decreased from 1300 eq/ha/yr in 2000 to 1050 eq/ha/yr in 2015 due mostly to reductions in oxidized nitrogen. Satellite data on ammonia was also able to improve ammonia emission estimates and redistribute deposition fluxes.

1. ESTABLISHING NITROGEN DEPOSITION OVER
GERMANY USING MODELLING AND OBSERVATIONS
R. Kranenburg, C. Hendriks, A. Segers, S. Banzhaf, H.D. Nagel, F. Schrader and M. Schaap

2. INTRODUCTION
Atmospheric deposition of nitrogen strongly contributes to eutrophication of
terrestrial and aquatic ecosystems.
Eutrophication causes a reduction in biodiversity, especially in ecosystems
that thrive on nutrient-poor conditions.
Nitrogen availability is a key parameter for carbon sequestration
Long-term trend calculation for total deposition of nitrogen over Germany
(2000-2015)
ESTABLISHING NITROGEN DEPOSITION OVER GERMANY USING MODELLING AND OBSERVATIONS

3. THREE DEPOSITION PATHWAYS
Dry Wet Occult
While observations of wet deposition are abundant, dry deposition measurements are
extremely challenging and thus scarce. To quantify nitrogen deposition, one therefore
relies on modelling.
Residual Kriging of
observations
supported by
modelled
distributions
Chemistry-
Transport-
Modelling
Empirical approach
using estimated cloud
water input

4. CHEMISTRY TRANSPORT MODELLING
LOTOS-EUROS
DEPAC 3.11
Compensation point
Emissions
German GRETA data
European TNO-MACC-III
Both reflecting reported
totals for 2000 – 2015
Land use: Corine-2012
Land use specific calculations
Application of the new UBA-Griddingtool emissions for ammonia
NH3 emissions in the 7x7 Km nest

5. ModelledKriged
Application of the new UBA-Griddingtool emissions for ammonia
*
1x1 Km2 precipitation
maps (DWD-REGNIE)
ESTIMATION OF WET DEPOSITION DISTRIBUTION
THROUGH RESIDUAL KRIGING OF QUALITY CONTROLLED
OBSERVATIONS OF NH4 IN PRECIPITATION

6. TOTAL DEPOSITION FOR NHX AND NOY
NHx – Coniferous forest NOy – Coniferous forest
2/3 1/3

7. 7 | Neue Hintergrunddepositionskarten für 2000 bis 2015

8. IMPACT OF COMPENSATION POINT
Introducing the compensation
point led to
A redistribution of reduced
nitrogen deposition across
Germany
Lower deposition in
agricultural source areas and
increased long range transport
A systematic shift increasing
wet deposition efficiency of
ammonia (~10%)
ESTABLISHING NITROGEN DEPOSITION OVER GERMANY USING MODELLING AND OBSERVATIONS

9. COMPARISON TO FLUX MEASUREMENTS
ESTABLISHING NITROGEN DEPOSITION OVER GERMANY USING MODELLING AND OBSERVATIONS
ForestFlux project - First comparison of deposition fluxes for reactive N

10. WHAT DO WE LEARN FROM SATELLITE DATA?
Application of the new UBA-Griddingtool emissions for ammonia
Satelite-IASI-NH3: 8-year average
Model

11. SATELLITE BASED EMISSION CORRECTION CONSISTENT
WITH THE LOTOS-EUROS BIAS IN WET DEPOSITION OF NH4
11 | Forschungsrichtungen an der FU-Berlin
Satellite derived correction factor
for NH3 emission in Germany
Fractional difference between
kriged and modelled wet deposition

12. CONCLUSIONS & OUTLOOK
We presented new quantitative estimates of the deposition of atmospheric
nitrogen to ecosystems across Germany.
On average, the nitrogen deposition in Germany has decreased from above
1300 eq ha-1 yr-1 in 2000 to about 1050 eq ha-1 yr-1 during 2015. This
reduction can be attributed to a reduction in oxidized nitrogen deposition.
Nitrogen deposition modelling is complex as the many interactions between
land use, meteorology and process descriptions cause a redistribution of the
deposition fluxes as illustrated for the compensation point.
Satellite data of NH3 provide useful information to improve the NH3 emissions
Outlook:
Improve ammonia emission variability through development of an
agricultural emission model
Assimilation of satellite derived ammonia distributions
More detailed comparison to ForestFlux and ICOS data
ESTABLISHING NITROGEN DEPOSITION OVER GERMANY USING MODELLING AND OBSERVATIONS

13. THANK YOU FOR YOUR ATTENTION
Take a look:
TIME.TNO.NL

14. Dry Wet Occult
RESULT OF THE KRIGING AND
PRECIPITATION MAP
Regional biases removed, while maintaining large scale gradients
Impact of orography

15. EXCEEDANCE OF THE CRITICAL LOAD
FOR EUTROPHICATION
15 | Neue Hintergrunddepositionskarten für 2000 bis 2015
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
kg N / (ha * a) keine 0 - 7,5 7,5 - 10 10 - 15 15 - 20 20 - 30 > 30
Quelle: eigene Darstellung, ÖKO-DATA Strausberg
Überschreitung der Critical Load für Eutrophierung durch Stickstoffeinträge auf den
kartierten empfindlichen Ökosystemflächen