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| Titel |
The 1985 Southern Hemisphere mid-latitude total column ozone anomaly |
| VerfasserIn |
G. E. Bodeker, H. Garny, D. Smale, M. Dameris, R. Deckert |
| 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 ; 7, no. 21 ; Nr. 7, no. 21 (2007-11-14), S.5625-5637 |
| Datensatznummer |
250005250
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| Publikation (Nr.) |
 copernicus.org/acp-7-5625-2007.pdf |
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| Zusammenfassung |
| One of the most significant events in the evolution of the ozone layer over southern
mid-latitudes since the late 1970s was the large decrease observed in 1985. This event
remains unexplained and a detailed investigation of the mechanisms responsible for the
event has not previously been undertaken. In this study, the 1985 Southern Hemisphere mid-latitude
total column ozone anomaly is analyzed in detail based on observed daily total column ozone fields,
stratospheric dynamical fields, and calculated diagnostics of stratospheric mixing. The 1985 anomaly
appears to result from a combination of (i) an anomaly in the meridional circulation resulting from the
westerly phase of the equatorial quasi-biennial oscillation (QBO), (ii) weaker transport of ozone from
its tropical mid-stratosphere source across the sub-tropical barrier to mid-latitudes related to the
particular phasing of the QBO with respect to the annual cycle, and (iii) a solar cycle induced
reduction in ozone. Similar QBO and solar cycle influences prevailed in 1997 and 2006 when again
total column ozone was found to be suppressed over southern mid-latitudes. The results based on
observations are compared and contrasted with analyses of ozone and dynamical fields from the
ECHAM4.L39(DLR)/CHEM coupled chemistry-climate model (hereafter referred to as E39C). Equatorial
winds in the E39C model are nudged towards observed winds between 10° S and 10° N
and the ability of this model to produce an ozone anomaly in 1985, similar to that
observed, confirms the role of the QBO in effecting the anomaly. |
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