Articles | Volume 4, issue 4
Geosci. Model Dev., 4, 1077–1102, 2011
Geosci. Model Dev., 4, 1077–1102, 2011

Model description paper 02 Dec 2011

Model description paper | 02 Dec 2011

Towards an online-coupled chemistry-climate model: evaluation of trace gases and aerosols in COSMO-ART

C. Knote2,1, D. Brunner2,1, H. Vogel3, J. Allan4, A. Asmi5, M. Äijälä5, S. Carbone6, H. D. van der Gon7, J. L. Jimenez8, A. Kiendler-Scharr9, C. Mohr10, L. Poulain11, A. S. H. Prévôt10, E. Swietlicki12, and B. Vogel3 C. Knote et al.
  • 1Laboratory for Air Pollution/Env. Technology, Empa Materials and Science, 8600 Duebendorf, Switzerland
  • 2C2SM Center for Climate Systems Modeling, ETH, Zurich, Switzerland
  • 3Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 4School of Earth Atmospheric, and Environmental Sciences, National Centre for Atmospheric Science, University of Manchester, Manchester, UK
  • 5Department of Physics, University of Helsinki, Helsinki, Finland
  • 6Air Quality Research, Finnish Meteorological Institute, Helsinki, Finland
  • 7TNO Princetonlaan 6, 3584 CB Utrecht, The Netherlands
  • 8CIRES and Dept. of Chemistry and Biochemistry, Univ. of Colorado, Boulder, CO, USA
  • 9Institut IEK-8, Troposphäre, Forschungszentrum Jülich, Jülich, Germany
  • 10Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
  • 11Leibniz Institute for Tropospheric Research, Leipzig, Germany
  • 12Division of Nuclear Physics, Department of Physics, Lund University, Lund, Sweden

Abstract. The online-coupled, regional chemistry transport model COSMO-ART is evaluated for periods in all seasons against several measurement datasets to assess its ability to represent gaseous pollutants and ambient aerosol characteristics over the European domain. Measurements used in the comparison include long-term station observations, satellite and ground-based remote sensing products, and complex datasets of aerosol chemical composition and number size distribution from recent field campaigns. This is the first time these comprehensive measurements of aerosol characteristics in Europe are used to evaluate a regional chemistry transport model. We show a detailed analysis of the simulated size-resolved chemical composition under different meteorological conditions. Mean, variability and spatial distribution of the concentrations of O3 and NOx are well reproduced. SO2 is found to be overestimated, simulated PM2.5 and PM10 levels are on average underestimated, as is AOD. We find indications of an overestimation of shipping emissions. Time evolution of aerosol chemical composition is captured, although some biases are found in relative composition. Nitrate aerosol components are on average overestimated, and sulfates underestimated. The accuracy of simulated organics depends strongly on season and location. While strongly underestimated during summer, organic mass is comparable in spring and autumn. We see indications for an overestimated fractional contribution of primary organic matter in urban areas and an underestimation of SOA at many locations. Aerosol number concentrations compare well with measurements for larger size ranges, but overestimations of particle number concentration with factors of 2–5 are found for particles smaller than 50 nm. Size distribution characteristics are often close to measurements, but show discrepancies at polluted sites. Suggestions for further improvement of the modeling system consist of the inclusion of a revised secondary organic aerosols scheme, aqueous-phase chemistry and improved aerosol boundary conditions. Our work sets the basis for subsequent studies of aerosol characteristics and climate impacts with COSMO-ART, and highlights areas where improvements are necessary for current regional modeling systems in general.