R.J. Wichink Kruit 1, D. Simpson 2, M. Schaap 1, R. Kranenburg 1, E. Dammers 1, C.A. Geels 3, C. Skjoth 4, M. Engardt 5, A. Graff 6, R. Stern 7, B. Bessagnet 8, L. Rouil 8, J.M. Baldasano 9, M. Pay 9, D. Hauglustaine 10, A. Nyiri 2, M.A. Sutton 11, S. Reis 11, P. Thunis 12 and C. Cuvelier 12 ÉCLAIRE model inter-comparison of atmospheric nitrogen deposition and concentrations over Europe 1 TNO, Dept. of Climate, Air and Sustainability, P.O. Box 80015, NL-3508TA Utrecht, The Netherlands 2 Norwegian Meteorological Institute, Air Pollution Section Research Department, P.O. Box 43, Blindern, N-0313, Oslo, Norway 3 Aarhus University, Department of Environmental Science-Atmospheric modeling, Frederiksborgvej 399, 4000 Roskilde, Denmark 4 University of Worcester, National Pollen and Aerobiology Research Unit, Henwick Grove, VR2 6AJ, Worcester, United Kingdom 5 SMHI, Norkoping 6 Umweltbundesamt, Postfach 1406, D Dessau-Roßlau, Germany 7 Freie Universität Berlin, Institut für Meteorologie und Troposphärische Umweltforschung, Carl-Heinrich-Becker Weg 6-10, D Berlin, Germany 8 INERIS, Institut National de l’Environnement Industriel et des Risques Parc Technologique, ALATA, F Verneuil-en-Halatte, France 9 Barcelona Supercomputing Center, c/ Jordi Girona 29, E Barcelona, Spain 10 Laboratoire des Sciences du Climat et de l’environnement, UMR 8212 CEA-CNRS-UVSQ, Gif-sur-Yvette, France 11 CEH, Natural Environmental Research Council, Bush Estate, Pinicuik, Midlothian, EH26 0QB 12 European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, I Ispra (Va), Italy

Motivation It is difficult to say anything about uncertainties in model calculations of Nr-deposition as there are no observations of total Nr deposition available yet. This study aims to: deliver an ensemble map of the total Nr-deposition over Europe based on 7 regional European CTMs, and to estimate the inter-model variation in the total Nr-deposition over Europe validate the models by comparing modelled wet depositions and concentrations with observations from the EMEP wet deposition network and NitroEurope IP

Model settings ECLAIRE model comparison Modelling the European Nitrogen budget 3 DomainnxnyΔLon ( °) ΔLat ( °) ΔLon x ΔLat (km x km) SW corner grid centre (Lon / Lat) Europe x 28 (N) 44 x 28 (S) / Emissions: provided by INERIS at 0.5° x 0.25° Longitude/Latitude Note: INCA used own emissions! Other Input: not prescribed. Output domain: Resolution: 0.5° x 0.25° (~28x28 km 2 ) DEHM: hemispheric (~ 50x50 km 2 ) INCA (global): 3.75° x 1.875° (~210x210 km 2 ) Models: EMEP, LOTOS-EUROS, DEHM, MATCH, CMAQ, CHIMERE, RCGC, INCA (global)

Individual model results ECLAIRE model comparison Modelling the European Nitrogen budget 4 EMEP CMAQ CHIMERE RCGC MATCHLOTOS- EUROS DEHM INCA dry NHx dry NOy wet NHx wet NOy

Ensemble of 7 regional CTMs: Total Nr ECLAIRE model comparison Modelling the European Nitrogen budget 5

Contribution of NHx to total Nr ECLAIRE model comparison Modelling the European Nitrogen budget 6

10-day running mean of model domain Total Nr ECLAIRE model comparison Modelling the European Nitrogen budget 7 Dry Nr ~ 40% Wet Nr ~ 60%

Contribution of dry Nr to total Nr ECLAIRE model comparison Modelling the European Nitrogen budget 8

ECLAIRE model comparison Modelling the European Nitrogen budget 9 10-day running mean of model domain Dry NOy ~ 35% Wet Noy ~ 65% Dry NHx ~ 45% Wet NHx ~ 55%

Conclusions from model inter-comparison This study showed that the total Nr-deposition (NHx +NOy) in the model domain were rather similar in all models The variation in model results is largest for the dry deposition of NHx Larger dry deposition is compensated by smaller wet deposition The average variation in the modeled Nr-deposition was about 30-50% over land and % over water NHx vs. NOy deposition is approximately 50% vs. 50%, but large regional differences! Dry versus wet deposition contributions are approximately 45% vs. 55% for NHx and 35% vs. 65% for NOy and 40% vs. 60% for total Nr (but large regional differences again!) KLD presentatie 24-maart 2011 Development of GHG projection guidelines 10

Comparison with EMEP wet deposition and NitroEurope IP observation ECLAIRE model comparison Modelling the European Nitrogen budget 11

Wet NHx [mg/m 2 ] wet NHxOBSERVED LOTOS- EUROSEMEPRCGCCMAQCHIMEREDEHMMATCHINCAENSEMBLE average stdev r bias rel. bias N68

Wet NOy [mg/m 2 ] wet NOyOBSERVED LOTOS- EUROSEMEPRCGCCMAQCHIMEREDEHMMATCHINCAENSEMBLE average stdev r bias rel. bias N68

NH 3 ECLAIRE model comparison Modelling the European Nitrogen budget 14 EMEP CMAQ CHIMERE RCGC MATCH LOTOS- EUROS DEHM INCA ENSEMBLE

NH 3 ECLAIRE model comparison Modelling the European Nitrogen budget 15 NH3OBSERVED LOTOS- EUROSEMEPRCGCCMAQCHIMEREDEHMMATCHINCAENSEMBLE average stdev r bias rel. bias N51

Conclusions from comparison with observations ECLAIRE model comparison Modelling the European Nitrogen budget 16 Ensemble results of the seven regional CTM models are generally better than the individual model results Modelled wet deposition of NOy correlates much better with observed wet deposition than NHx. Regional CTMs are well able to estimate ‘background’ NH 3 concentrations Data from NitroEurope IP is very useful for the ECLAIRE model evaluation! Further analysis of the model-measurement comparison and reasons for inter-model differences is a priority for the next phase in ECLAIRE.

Thank you! ECLAIRE model comparison Modelling the European Nitrogen budget 17

HNO 3 ECLAIRE model comparison Modelling the European Nitrogen budget 18