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Atmos. Chem. Phys. Discuss., 10, 30473-30537, 2010
www.atmos-chem-phys-discuss.net/10/30473/2010/ doi:10.5194/acpd-10-30473-2010 © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. |
High-ozone layers in the middle and upper troposphere above Central Europe: potential import from the stratosphere along the subtropical jet stream
1Karlsruher Institut für Technologie, Institut für Meteorologie und Klimaforschung (IMK-IFU), Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, Germany
2Paul Scherrer Institut, Labor für Atmosphärenchemie, 5232 Villigen PSI, Switzerland
3Eidgenössische Technische Hochschule (ETH) Zürich, Institut für Atmosphäre und Klima, Universitätsstr. 16, 8092 Zürich, Switzerland
4Lehrstuhl für Ökoklimatologie, Technische Universität München, Am Hochanger 13, 85354 Freising-Weihenstephan, Germany
*now at: Norwegian Institute for Air Research, P.O. Box 100, Instituttveien 18, 2027 Kjeller, Norway
Abstract. Specific very dry high-ozone layers have been repeatedly observed in the middle and upper troposphere with the ozone lidar in Garmisch-Partenkirchen (Germany), starting roughly two days after the onset of high-pressure periods during the warm season. These episodes, previously not understood, were recently analysed based on extended simulations with the FLEXPART particle dispersion model and jet-stream analyses with the LAGRANTO transport model. The model results indicate import from the stratosphere along the subtropical jet stream over the Pacific Ocean and all the way back to the Atlantic Ocean, in some cases mixed with stratospheric air from intrusions over the North-West Pacific Ocean. Occasionally, also air from the boundary layers of East Asia and North America was admixed. The analysis suggests that stratospheric influence is the most important factor for the increase in ozone and is related to a rather shallow transfer of air from the stratosphere into the rapid upper-and mid-tropospheric air streams observed with the lidar. The in part considerable vertical and temporal extent of these layers and peak ozone mixing ratios between 80 and 150 \unit{ppb} suggest this to be an important mechanism for stratosphere-to-troposphere transport.
Citation: Trickl, T., Bärtsch-Ritter, N., Eisele, H., Furger, M., Mücke, R., Sprenger, M., and Stohl, A.: High-ozone layers in the middle and upper troposphere above Central Europe: potential import from the stratosphere along the subtropical jet stream, Atmos. Chem. Phys. Discuss., 10, 30473-30537, doi:10.5194/acpd-10-30473-2010, 2010.