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| Titel |
Antarctic ozone variability inside the polar vortex estimated from balloon measurements |
| VerfasserIn |
M. C. Parrondo, M. Gil, M. Yela, B. J. Johnson, H. A. Ochoa |
| 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 ; 14, no. 1 ; Nr. 14, no. 1 (2014-01-09), S.217-229 |
| Datensatznummer |
250118253
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| Publikation (Nr.) |
 copernicus.org/acp-14-217-2014.pdf |
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| Zusammenfassung |
| Thirteen years of ozone soundings at the Antarctic Belgrano II station
(78° S, 34.6° W) have been analysed to establish a
climatology of stratospheric ozone and temperature over the area. The station
is inside the polar vortex during the period of development of chemical ozone
depletion. Weekly periodic profiles provide a suitable database for seasonal
characterization of the evolution of stratospheric ozone, especially valuable
during wintertime, when satellites and ground-based instruments based on
solar radiation are not available. The work is focused on ozone loss rate
variability (August–October) and its recovery (November–December) at
different layers identified according to the severity of ozone loss. The time window selected for the calculations
covers the phase of a quasi-linear ozone reduction, around day 220 (mid-August) to day 273 (end of September). Decrease
of the total ozone column over Belgrano during spring is highly dependent on
the meteorological conditions. Largest depletions (up to 59%) are
reached in coldest years, while warm winters exhibit significantly lower ozone
loss (20%). It has been found that about 11% of the total O3
loss, in the layer where maximum depletion occurs, takes place before
sunlight has arrived, as a result of transport to Belgrano of air from a somewhat lower
latitude, near the edge of the polar vortex, providing evidence of mixing
inside the vortex. Spatial homogeneity of the vortex has been examined by
comparing Belgrano results with those previously obtained for South Pole
station (SPS) for the same altitude range and for 9 yr of overlapping data.
Results show more than 25% higher ozone loss rate at SPS than at
Belgrano. The behaviour can be explained taking into account (i) the
transport to both stations of air from a somewhat lower latitude, near the
edge of the polar vortex, where sunlight reappears sooner, resulting in
earlier depletion of ozone, and (ii) the accumulated hours of sunlight, which
become much greater at the South Pole after the spring equinox. According to
the variability of the ozone hole recovery, a clear connection between the
timing of the breakup of the vortex and the monthly ozone content was found.
Minimum ozone concentration of 57 DU in the 12–24 km layer remained in
November, when the vortex is more persistent, while in years when the final
stratospheric warming took place "very early", mean integrated ozone rose
by up to 160–180 DU. |
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