Pope, RJ orcid.org/0000-0002-3587-837X, Chipperfield, MP, Arnold, SR orcid.org/0000-0002-4881-5685 et al. (6 more authors) (2018) Influence of the wintertime North Atlantic Oscillation on European tropospheric composition: an observational and modelling study. Atmospheric Chemistry and Physics, 18 (11). pp. 8389-8408. ISSN 1680-7316
Abstract
We have used satellite observations and a simulation from the TOMCAT chemistry transport model (CTM) to investigate the influence of the well-known wintertime North Atlantic Oscillation (NAO) on European tropospheric composition. Under the positive phase of the NAO (NAO-high), strong westerlies tend to enhance transport of European pollution (e.g. nitrogen oxides, NOx; carbon monoxide, CO) away from anthropogenic source regions. In contrast, during the negative phase of the NAO (NAO-low), more stable meteorological conditions lead to a build-up of pollutants over these regions relative to the wintertime average pollution levels. However, the secondary pollutant ozone shows the opposite signal of larger values during NAO-high. NAO-high introduces Atlantic ozone-enriched air into Europe, while under NAO-low westerly transport of ozone is reduced, yielding lower values over Europe. Furthermore, ozone concentrations are also decreased by chemical loss through the reaction with accumulated primary pollutants such as nitric oxide (NO) in NAO-low. Peroxyacetyl nitrate (PAN) in the upper troposphere–lower stratosphere (UTLS) peaks over Iceland and southern Greenland in NAO-low, between 200 and 100 hPa, consistent with the trapping by an anticyclone at this altitude. Model simulations show that enhanced PAN over Iceland and southern Greenland in NAO-low is associated with vertical transport of polluted air from the mid-troposphere into the UTLS. Overall, this work shows that NAO circulation patterns are an important governing factor for European wintertime composition and air pollution.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2018, Author(s). This work is distributed under the Creative Commons Attribution 4.0 License [https://creativecommons.org/licenses/by/4.0/]. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > National Centre for Atmos Science (NCAS) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 28 Jun 2018 16:06 |
Last Modified: | 09 Oct 2020 11:12 |
Status: | Published |
Publisher: | Copernicus Publications (EGU) |
Identification Number: | 10.5194/acp-18-8389-2018 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:132527 |
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