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| Titel |
Stratospheric ozone chemistry in the Antarctic: what determines the lowest ozone values reached and their recovery? |
| VerfasserIn |
J.-U. Grooß, K. Brautzsch, R. Pommrich, S. Solomon, R. Müller |
| 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 ; 11, no. 23 ; Nr. 11, no. 23 (2011-12-07), S.12217-12226 |
| Datensatznummer |
250010246
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| Publikation (Nr.) |
 copernicus.org/acp-11-12217-2011.pdf |
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| Zusammenfassung |
| Balloon-borne observations of ozone from the South Pole Station have
been reported to reach ozone mixing ratios below the detection limit
of about 10 ppbv at the 70 hPa level by late September. After
reaching a minimum, ozone mixing ratios increase to above
1 ppmv on the 70 hPa level by late December. While the basic
mechanisms causing the ozone hole have been known for more than 20 yr,
the detailed chemical processes determining how low the local
concentration can fall, and how it recovers from the minimum have
not been explored so far. Both of these aspects are investigated
here by analysing results from the Chemical Lagrangian Model of the
Stratosphere (CLaMS).
As ozone falls below about 0.5 ppmv, a balance is maintained by gas
phase production of both HCl and HOCl followed by heterogeneous
reaction between these two compounds in these simulations.
Thereafter, a very rapid, irreversible chlorine deactivation into
HCl can occur, either when ozone drops to values low enough for gas
phase HCl production to exceed chlorine activation processes or when
temperatures increase above the polar stratospheric cloud (PSC)
threshold. As a consequence, the timing and mixing ratio of the
minimum ozone depends sensitively on model parameters, including the
ozone initialisation. The subsequent ozone increase between October
and December is linked mainly to photochemical ozone production,
caused by oxygen photolysis and by the oxidation of carbon monoxide
and methane. |
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