1Meteorology and Air Quality Section, Wageningen University, Wageningen, The Netherlands
2TNO, Earth, Environment and Life Sciences, research group Climate, Air and Sustainability, Utrecht, The Netherlands
3European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy
4Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
5Finnish Meteorological Institute, Helsinki, Finland
6Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
7Institute for Marine and Atmospheric Research Utrecht, The Netherlands
Received: 28 Jun 2010 – Published in Atmos. Chem. Phys. Discuss.: 08 Sep 2010
Abstract. This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension). We model that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95%) and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%). We model transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we underestimate the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match), while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional) aerosol budgets, as presented in the current study.
Revised: 17 Jan 2011 – Accepted: 27 Jan 2011 – Published: 09 Feb 2011
Aan de Brugh, J. M. J., Schaap, M., Vignati, E., Dentener, F., Kahnert, M., Sofiev, M., Huijnen, V., and Krol, M. C.: The European aerosol budget in 2006, Atmos. Chem. Phys., 11, 1117-1139, doi:10.5194/acp-11-1117-2011, 2011.