Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 1725-1743, 2015
https://doi.org/10.5194/acp-15-1725-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
19 Feb 2015
The role of aerosol in altering North Atlantic atmospheric circulation in winter and its impact on air quality
F. S. R. Pausata1,2,*, M. Gaetani1,**, G. Messori2, S. Kloster3, and F. J. Dentener1 1European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra (VA), Italy
2Department of Meteorology, Stockholm University and Bolin Centre for Climate Research, Stockholm, Sweden
3Land in the Earth System, Max Planck Institute for Meteorology, Hamburg, Germany
*now at: Department of Meteorology, Stockholm University and Bolin Centre for Climate Research, Stockholm, Sweden
**now at: LATMOS-IPSL, Université Pierre et Marie Curie, Paris, France
Abstract. Numerical model scenarios of future climate depict a global increase in temperatures and changing precipitation patterns, primarily driven by increasing greenhouse gas (GHG) concentrations. Aerosol particles also play an important role by altering the Earth's radiation budget and consequently surface temperature. Here, we use the general circulation aerosol model ECHAM5-HAM, coupled to a mixed layer ocean model, to investigate the impacts of future air pollution mitigation strategies in Europe on winter atmospheric circulation over the North Atlantic. We analyse the extreme case of a maximum feasible end-of-pipe reduction of aerosols in the near future (2030), in combination with increasing GHG concentrations. Our results show a more positive North Atlantic Oscillation (NAO) mean state by 2030, together with a significant eastward shift of the southern centre of action of sea-level pressure (SLP). Moreover, we show a significantly increased blocking frequency over the western Mediterranean.

By separating the impacts of aerosols and GHGs, our study suggests that future aerosol abatement may be the primary driver of both the eastward shift in the southern SLP centre of action and the increased blocking frequency over the western Mediterranean. These concomitant modifications of the atmospheric circulation over the Euro-Atlantic sector lead to more stagnant weather conditions that favour air pollutant accumulation, especially in the western Mediterranean sector. Changes in atmospheric circulation should therefore be included in future air pollution mitigation assessments. The indicator-based evaluation of atmospheric circulation changes presented in this work will allow an objective first-order assessment of the role of changes in wintertime circulation on future air quality in other climate model simulations.


Citation: Pausata, F. S. R., Gaetani, M., Messori, G., Kloster, S., and Dentener, F. J.: The role of aerosol in altering North Atlantic atmospheric circulation in winter and its impact on air quality, Atmos. Chem. Phys., 15, 1725-1743, https://doi.org/10.5194/acp-15-1725-2015, 2015.
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our study suggests that future aerosol abatement may be the primary driver of increased blocking events over the western Mediterranean. This modification of the atmospheric circulation over the Euro-Atlantic sector leads to more stagnant weather conditions that favour air pollutant accumulation especially in the western Mediterranean sector. Changes in atmospheric circulation should therefore be included in future air pollution mitigation assessments.
our study suggests that future aerosol abatement may be the primary driver of increased...
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