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| Titel |
The unusual persistence of an ozone hole over a southern mid-latitude station during the Antarctic spring 2009: a multi-instrument study |
| VerfasserIn |
E. A. Wolfram, J. Salvador, F. Orte, R. D'Elia, S. Godin-Beekmann, J. Kuttippurath, A. Pazmino, F. Goutail, C. Casiccia, F. Zamorano, N. Paes Leme, E. J. Quel |
| 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 ; 30, no. 10 ; Nr. 30, no. 10 (2012-10-02), S.1435-1449 |
| Datensatznummer |
250017274
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| Publikation (Nr.) |
 copernicus.org/angeo-30-1435-2012.pdf |
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| Zusammenfassung |
| Record-low ozone column densities (with a minimum of 212 DU) persisted over
three weeks at the Río Gallegos NDACC (Network for the Detection of
Atmospheric Composition Change) station (51.5° S, 69.3° W) in November
2009. Total ozone remained two standard deviations below the climatological
mean for five consecutive days during this period. The statistical analysis
of 30 years of satellite data from the Multi Sensor Reanalysis (MSR)
database for Río Gallegos revealed that such a long-lasting low-ozone
episode is a rare occurrence. The event is examined using height-resolved
ozone lidar measurements at Río Gallegos, and observations from satellite
and ground-based instruments. The computed relative difference between the
measured total ozone and the climatological monthly mean shows reductions
varying between 10 and 30% with an average decrease of 25%. The mean
absolute difference of total ozone column with respect to climatological
monthly mean ozone column is around 75 DU. Extreme values of the UV index
(UVI) were measured at the ground for this period, with the daily maximum
UVI of around 13 on 15 and 28 November. The high-resolution MIMOSA-CHIM (Modélisation
Isentrope du transport Méso-échelle de l'Ozone Stratosphérique par Advection)
model was used to interpret the ozone depletion event. An ozone decrease of
about 2 ppmv was observed in mid-November at the 550 K isentropic level
(~22 km). The position of Río Gallegos relative to the polar
vortex was classified using equivalent latitude maps. During the second
week of November, the vortex was over the station at all isentropic levels,
but after 20 November and until the end of the month, only the 10 lower
levels in the stratosphere were affected by vortex overpasses with ozone
poor air masses. A rapid recovery of the ozone column density was observed
later, due to an ozone rich filament moving over Río Gallegos between
18 and 24 km in the first two weeks of December 2009. |
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