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Atmos. Chem. Phys. Discuss., 10, 9895-9916, 2010
www.atmos-chem-phys-discuss.net/10/9895/2010/ doi:10.5194/acpd-10-9895-2010 © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. |
Will climate change increase ozone depletion from low-energy-electron precipitation?
1Max Planck Institute for Chemistry, 55020 Mainz, Germany
2Deutsches Zentrum für Luft-und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, 82234 Weßling, Germany
Abstract. We investigate the effects of a strengthened Brewer-Dobson circulation on the transport of nitric oxide (NO) produced by energetic particle precipitation. During periods of high geomagnetic activity, low-energy-electron precipitation is responsible for winter time ozone loss in the polar middle atmosphere between 1 and 6 hPa. However, as climate change is expected to increase the strength of the Brewer-Dobson circulation, the enhancements of NOx concentrations are expected to be transported to lower altitudes in extra-tropical regions, becoming even more significant in the ozone budget. We use simulations with the chemistry climate model system ECHAM5/MESSy to compare present day effects of low-energy-electron precipitation with expected effects in a climate change scenario for the year 2100. In years of strong geomagnetic activity, similar to that observed in 2003, an additional polar ozone loss of up to 0.5 μmol/mol at 5 hPa is found. However, this would be approximately compensated by an ozone enhancement originating from a stronger poleward transport of ozone from lower latitudes caused by a strengthened Brewer-Dobson circulation, as well as by slower photochemical ozone loss reactions in a stratosphere cooled by risen greenhouse gas concentrations.
Citation: Baumgaertner, A. J. G., Jöckel, P., Dameris, M., and Crutzen, P. J.: Will climate change increase ozone depletion from low-energy-electron precipitation?, Atmos. Chem. Phys. Discuss., 10, 9895-9916, doi:10.5194/acpd-10-9895-2010, 2010.