Atmospheric Circulation Changes in Response to an Observed Stratospheric Zonal Ozone Anomaly |
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| Authors: | Dieter H W Peters Andrea Schneidereit Marianne Bügelmayer Christoph Zülicke Ingo Kirchner |
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| Institution: | 1. Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Mecklenburg, Germanypeters@iap-kborn.de;3. Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Mecklenburg, Germany;4. Faculty of Earth and Life Sciences, Cluster Earth and Climate, Vrije Universiteit, Amsterdam, The Netherlands;5. Meteorologisches Institut, FU Berlin, Germany |
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| Abstract: | AbstractIn a sensitivity study, the influence of an observed stratospheric zonal ozone anomaly on the atmospheric circulation was investigated using the Fifth Generation European Centre Hamburg Model (ECHAM5) which is a general circulation model. The model was run from 1960 to 1999 (40 years) with a mean seasonal cycle of zonally symmetric ozone. In order to isolate the induced dynamical influence of the observed zonally asymmetric part of the three-dimensional stratospheric ozone, a second run was performed for the boreal extratropics using prescribed monthly means from the 40-year reanalysis dataset from the European Centre for Medium-range Weather Forecasts (ERA-40). The main findings are the interdecadal westward shift of the polar vortex at about 65°N and a significant increase in the number of stratospheric sudden warmings during the 1980–99 period. Under the action of zonally asymmetric ozone a decrease in the Arctic Oscillation was identified between the mid-1980s and the mid-1990s. The lag correlation between the mean Arctic Oscillation at the surface and the daily stratospheric northern annular mode increased in mid-winter. Furthermore, we examined the influence of the stratospheric zonal ozone anomaly on Rossby wave breaking in the upper troposphere and found a significant westward shift of poleward Rossby wave breaking events over western Europe in the winter. By this we show that the stratospheric zonal ozone anomaly has a strong influence on the tropospheric circulation as a result of enhanced dynamical coupling processes. |
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| Keywords: | atmospheric circulation zonal ozone anomaly northern annular mode Rossby wave breaking |
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