1. Norwegian Meteorological Institute
Uncertainty in the future nitrogen load to the Baltic Sea due to unknown meteorological conditions
Jerzy Bartnicki
Norwegian Meteorological Institute

2. Background
Eutriphication due to nitrogen load is a serious and expensive problem for the Baltic Sea
Atmospheric part of nitrogen load is 25-30%
In the frame of agreement between HELCOM and EMEP, atmospheric load of nitrogen is calculated every year based on updated emissions and meteorological data
EMEP Unified model is used for calculation of nitrogen depositions to the Baltic Sea, as well as source receptor matrices
The Source receptor matrix gives the contribution of each of more than 50 emission sources (EMEP countries, ship emissions etc.) to the deposition
What about the future?

3. Practical problem
Following Gothenburg Protocol and EU NEC Directive, the nitrogen emissions will be reduced in 2010 for most of the sources
How will it affect atmospheric deposition of nitrogen to the Baltic Sea and its sub-regions in 2010?
Which sources will contribute most to the deposition in 2010?
Request from HELCOM to EMEP
What about uncertainty of the prediction? What will be uncertainty due to unknown meteorological conditions?

4. Simple solution
Compilation of 2010 nitrogen emissions in the model grid system following Gothenburg Protocol and EU NEC Directive (+ 2 additional scenarios)
Runs of EMEP Unified model using meteorological data for: 1996, 1997,1998, 2000
Computation of nitrogen deposition for each of available meteorological year
Computation of source receptor matrices for each of available meteorological year

5. HELCOM CP’s Denmark Estonia Finland Germany Latvia Lithuania Poland
Sweden
Russian Federation +
Europan Commision

6. N0x emission sources for 2010

7. NH3 emission sources for 2010

8. 2010 annual emission maps

9. Ship NOx emissions

10. EMEP Unified model Eulerian, 170 × 133 grids, Δx=50 km
20 vertical layers up to 10 km
Topography and land use included
Meteorological data every 6 hour (300TB – 1 year)
150 chemical reactions also in clouds
Dry deposition processes
Wet deposition with in cloud and below cloud scavenging
1 year simulation – 2 hours execution time

11. 2010 deposition maps
N oxidized
N reduced

12. 2010 deposition maps
N dry
N wet

13. 2010 deposition map – total N

14. Catchments and sub-basins

15. Depositions to sub-basins

16. Depositions to sub-basins

17. Depositions to sub-basins

18. Depositions to the Baltic Sea

19. Main contributing sources to deposition

20. Main contributing sources to deposition

21. Main contributing sources to deposition

22. Main sources for total nitrogen deposition to the Baltic Sea

23. Uncertainty of the contributions

24. Uncertainty of the contributions to the Baltic Sea

25. Conclusions
More model runs with the same emissions and different meteorological years necessary to have a better idea about the probability distribution
A longer period than one year is necessary to evaluate the effects of nitrogen emission reductions.
The results of this project had an impact on the plans for the future emission reductions of nitrogen oxides and ammonia in Europe