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Ann. Geophys., 21, 2107-2118, 2003
www.ann-geophys.net/21/2107/2003/
© European Geosciences Union 2003
Modelling the wintertime response to upper tropospheric and lower stratospheric ozone anomalies over the North Atlantic and Europe
I. Kirchner1 and D. Peters2
1Freie Universität, Institut für Meteorologie, Carl-Heinrich-Becker-Weg 6-10, D-12165 Berlin, Germany
2Universität Rostock, Leibniz-Institut für Atmosphärenphysik, Schlossstraße 6, D-18225 Kühlungsborn, Germany
Abstract. During boreal winter
months, mean longitude-dependent ozone changes in the upper troposphere and
lower stratosphere are mainly caused by different ozone transport by planetary
waves. The response to radiative perturbation induced by these ozone changes
near the tropopause on the circulation is unclear. This response is
investigated with the ECHAM4 general circulation model in a sensitivity study.
In the simulation two different mean January realizations of the ozone field
are implemented in ECHAM4. Both ozone fields are estimated on the basis of the
observed mean January planetary wave structure of the 1980s. The first field
represents a 14-year average (reference, 1979–1992) and the second one
represents the mean ozone field change (anomaly, 1988–92) in boreal
extra-tropics during the end of the 1980s. The model runs were carried out
pairwise, with identical initial conditions for both ozone fields. Five
statistically independent experiments were performed, forced with the observed
sea surface temperatures for the period 1988 to 1992. The results support the
hypothesis that the zonally asymmetric ozone changes of the 80s triggered a
systematic alteration of the circulation over the North Atlantic – European
region. It is suggested that this feedback process is important for the
understanding of the decadal coupling between troposphere and stratosphere, as
well as between subtropics and extra-tropics in winter.
Key words. Meteorology and
atmospheric dynamics (general circulation; radiative processes; synoptic-scale
meteorology)
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