An evaluation of European nitrogen and sulfur wet deposition and their trends estimated by six chemistry transport models for the period 1990–2010
Journal article, 2019
Decreasing trends in WNOx were observed at most sites for both 11-year periods, with larger trends, on average, for the second period. The models also estimated predominantly decreasing trends at the monitoring sites and all but one of the models estimated larger trends, on average, for the second period. Decreasing trends were also observed at most sites for WNHx, although larger trends, on average, were observed for the first period. This pattern was not reproduced by the models, which estimated smaller decreasing trends, on average, than those observed or even small increasing trends. The largest observed trends were for WSOx, with decreasing trends at more than 80 % of the sites. On average, the observed trends were larger for the first period. All models were able to reproduce this pattern, although some models underestimated the trends (by up to a factor of 4) and others overestimated them (by up to 40 %), on average. These biases in modelled trends were directly related to the tendency of the models to under- or overestimate annual wet deposition and were smaller for the relative trends (expressed as % yr−1 relative to the deposition at the start of the period).
The fact that model biases were fairly constant throughout the time series makes it possible to improve the predictions of wet deposition for future scenarios by adjusting the model estimates using a bias correction calculated from past observations. An analysis of the contributions of various factors to the modelled trends suggests that the predominantly decreasing trends in wet deposition are mostly due to reductions in emissions of the precursors NOx, NH3 and SOx. However, changes in meteorology (e.g. precipitation) and other (non-linear) interactions partially offset the decreasing trends due to emission reductions during the first period but not the second. This suggests that the emission reduction measures had a relatively larger effect on wet deposition during the second period, at least for the sites with observations.
Author
M. R. Theobald
Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (Ciemat)
Marta G. Vivanco
Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (Ciemat)
W. Aas
Norwegian Institute for Air Research (NILU)
Camilla Andersson
SMHI
Giancarlo Ciarelli
Florian Couvidat
Institut National de l'Environnement Industriel et des Risques (INERIS)
Kees Cuvelier
Joint Research Centre (JRC), European Commission
Astrid Manders
Netherlands Organisation for Applied Scientific Research (TNO)
Mihaela Mircea
ENEA Centro Ricerche Bologna
Maria-Teresa Pay
Barcelona Supercomputing Center (BSC)
S. Tsyro
Norwegian Meteorological Institute
Mario Adani
ENEA Centro Ricerche Bologna
Robert Bergström
SMHI
Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing
B. Bessagnet
Institut National de l'Environnement Industriel et des Risques (INERIS)
Gino Briganti
ENEA Centro Ricerche Bologna
Andrea Cappelletti
ENEA Centro Ricerche Bologna
Massimo D'Isidoro
ENEA Centro Ricerche Bologna
Hilde Fagerli
Norwegian Meteorological Institute
Kathleen Mar
Institute for Advanced Sustainability Studies (IASS)
Noelia Otero
Institute for Advanced Sustainability Studies (IASS)
Valentin Raffort
École des Ponts ParisTech
Electricite de France (EDF)
Yelva Roustan
Electricite de France (EDF)
École des Ponts ParisTech
M. Schaap
Netherlands Organisation for Applied Scientific Research (TNO)
Peter Wind
Norwegian Meteorological Institute
University of Tromsø – The Arctic University of Norway
Augustin Colette
Institut National de l'Environnement Industriel et des Risques (INERIS)
Atmospheric Chemistry and Physics
1680-7316 (ISSN) 1680-7324 (eISSN)
Vol. 19 1 379-405Subject Categories
Meteorology and Atmospheric Sciences
Roots
Basic sciences
DOI
10.5194/acp-19-379-2019