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| Titel |
Results of an interactively coupled atmospheric chemistry – general circulation model: Comparison with observations |
| VerfasserIn |
R. Hein, M. Dameris, C. Schnadt, C. Land, V. Grewe, I. Köhler, M. Ponater, R. Sausen, B. B. Steil, J. Landgraf, C. Brühl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 19, no. 4 ; Nr. 19, no. 4, S.435-457 |
| Datensatznummer |
250014237
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| Publikation (Nr.) |
 copernicus.org/angeo-19-435-2001.pdf |
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| Zusammenfassung |
The coupled
climate-chemistry model ECHAM4.L39(DLR)/CHEM is presented which enables a
simultaneous treatment of meteorology and atmospheric chemistry and their
feedbacks. This is the first model which interactively combines a general
circulation model with a chemical model, employing most of the important
reactions and species necessary to describe the stratospheric and upper
tropospheric ozone chemistry, and which is computationally fast enough to allow
long-term integrations with currently available computer resources. This is
possible as the model time-step used for the chemistry can be chosen as large as
the integration time-step for the dynamics. Vertically the atmosphere is
discretized by 39 levels from the surface up to the top layer which is centred at 10 hPa, with a relatively high vertical resolution of approximately 700 m
near the extra-tropical tropopause. We present the results of a control
simulation representing recent conditions (1990) and compare it to available
observations. The focus is on investigations of stratospheric dynamics and
chemistry relevant to describe the stratospheric ozone layer. ECHAM4.L39(DLR)/CHEM
reproduces main features of stratospheric dynamics in the arctic vortex region,
including stratospheric warming events. This constitutes a major improvement
compared to earlier model versions. However, apparent shortcomings in Antarctic circulation and temperatures persist. The seasonal and interannual variability
of the ozone layer is simulated in accordance with observations. Activation and
deactivation of chlorine in the polar stratospheric vortices and their
inter-hemispheric differences are reproduced. Considering methane oxidation as
part of the dynamic-chemistry feedback results in an improved representation of
the spatial distribution of stratospheric water vapour concentrations. The
current model constitutes a powerful tool to investigate, for instance, the
combined direct and indirect effects of anthropogenic trace gas emissions.
Key words. Atmospheric composition
and structure (middle atmosphere – composition and chemistry) – Meteorology
and atmospheric dynamics (general circulation; middle atmosphere dynamics) |
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