EGU21-15634, updated on 23 Aug 2023
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evaluation of high-resolution air pollution modelling for the continental Nordic countries

Lise M. Frohn1, Jørgen Brandt1, Camilla Andersson2, Christopher Anderssen1, Cecilia Bennet2, Jesper H. Christensen1, Ulas Im1, Niko Karvosenoja3, Jaakko Kukkonen4, Susana Lopez-Aparicio5, Ole-Kenneth Nielsen1, Yuliia Palamarchuk4, Ville-Veikko Paunu3, Marlene Smith Plejdrup1, David Segersson2, Mikhail Sofiev4, and Camilla Geels1
Lise M. Frohn et al.
  • 1Aarhus University, Environmental Science, Denmark (
  • 2Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
  • 3Finnish Environment Institute (SYKE), Helsinki, Finland
  • 4Finnish Meteological Institute, Helsinki, Finland
  • 5NILU – Norwegian Institute for Air Research, Kjeller, Norway

This study presents the evaluation of the high-resolution air pollution model UBMv10, which has been set-up for a 2,900,000 km2 domain covering Norway, Sweden, Finland and Denmark with a 1 km x 1 km resolution and run for the time period 1979-2018. The UBMv10 is coupled to a long-range transport-chemistry model, DEHM, for boundary conditions. High-resolution emission data input and measurements of urban and rural air pollution concentrations have been obtained within the NordicWelfAir project from the four countries, in order to provide input and basis for evaluation of the UBM model.

In the NordicWelfAir project, the modelled hourly mean concentrations of air pollutants for the 40 year time period on this high resolution are applied in various epidemiological studies of the link between air pollution and health effects. The model results represent concentrations at the rural and urban background local scale level which in this study are evaluated for the components NO2, O3 and PM2.5, which are the most important components to address when studying health effects of air pollution.

The simplicity of the model makes it possible to perform model runs for a combination of large domains with high resolution and long time periods that is currently very difficult to obtain with more comprehensive Eulerian high-resolution models, which take much longer time to run, since they are limited by the Courant–Friedrichs–Lewy (CFL) stability criteria. When studying the long-term effects of air pollution components, e.g. with the home address of individuals in a cohort as proxy, these high-resolution model runs are required.

The evaluation is part of a study with the aim to investigate, how well the UBM model with its relatively simple description of atmospheric dispersion and chemistry captures the temporal and spatial variations in the four Nordic countries. In general, the model performs relatively well for describing the temporal variations with correlation coefficients around 0.5-0.8. The model has a tendency to overestimate NO2 levels with a few µg for all four countries, and overestimate PM2.5 with for Norway and Sweden with 3-5 µg across all stations.

The coupled model setup will be presented together with examples of 40 years of high-resolution model results for the four Nordic countries as well as the results of the model evaluation against measurements in the domain.

How to cite: Frohn, L. M., Brandt, J., Andersson, C., Anderssen, C., Bennet, C., Christensen, J. H., Im, U., Karvosenoja, N., Kukkonen, J., Lopez-Aparicio, S., Nielsen, O.-K., Palamarchuk, Y., Paunu, V.-V., Smith Plejdrup, M., Segersson, D., Sofiev, M., and Geels, C.: Evaluation of high-resolution air pollution modelling for the continental Nordic countries, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15634,, 2021.

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