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Titel |
Circulation anomalies in the Southern Hemisphere and ozone changes |
VerfasserIn |
P. Braesicke, J. Keeble, X. Yang, G. Stiller, S. Kellmann, N. L. Abraham, A. Archibald, P. Telford, J. A. Pyle |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 21 ; Nr. 13, no. 21 (2013-11-04), S.10677-10688 |
Datensatznummer |
250085786
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Publikation (Nr.) |
copernicus.org/acp-13-10677-2013.pdf |
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Zusammenfassung |
We report results from two pairs of chemistry-climate model simulations
using the same climate model but different chemical perturbations. In each
pair of experiments an ozone change was triggered by a simple change in the
chemistry. One pair of model experiments looked at the impact of polar
stratospheric clouds (PSCs) and the other pair at the impact of short-lived
halogenated species on composition and circulation. The model response is
complex with both positive and negative changes in ozone concentration,
depending on location. These changes result from coupling between
composition, temperature and circulation. Even though the causes of the
modelled ozone changes are different, the high latitude Southern Hemisphere
response in the lower stratosphere is similar. In both pairs of experiments
the high-latitude circulation changes, as evidenced by N2O differences,
are suggesting a slightly longer-lasting/stronger stratospheric descent in
runs with higher ozone destruction (a manifestation of a seasonal shift in
the circulation). We contrast the idealised model behaviour with interannual
variability in ozone and N2O as observed by the MIPAS instrument on
ENVISAT, highlighting similarities of the modelled climate equilibrium
changes to the year 2006–2007 in observations. We conclude that the climate
system can respond quite sensitively in its seasonal evolution to small
chemical perturbations, that circulation adjustments seen in the model can
occur in reality, and that coupled chemistry-climate models allow a better
assessment of future ozone and climate change than recent CMIP-type models
with prescribed ozone fields. |
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