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| Titel |
Polar processing in a split vortex: Arctic ozone loss in early winter 2012/2013 |
| VerfasserIn |
G. L. Manney, Z. D. Lawrence, M. L. Santee, N. J. Livesey, A. Lambert, M. C. Pitts |
| 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 ; 15, no. 10 ; Nr. 15, no. 10 (2015-05-19), S.5381-5403 |
| Datensatznummer |
250119731
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| Publikation (Nr.) |
 copernicus.org/acp-15-5381-2015.pdf |
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| Zusammenfassung |
| A sudden stratospheric warming (SSW) in early January 2013 caused the
Arctic polar vortex to split and temperatures to rapidly rise above the
threshold for chlorine activation. However, ozone in the lower
stratospheric polar vortex from late December 2012 through early
February 2013 reached the lowest values on record for that time of
year. Analysis of Aura Microwave Limb Sounder (MLS) trace gas
measurements and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite
Observations (CALIPSO) polar stratospheric cloud (PSC) data shows that
exceptional chemical ozone loss early in the 2012/13 Arctic winter
resulted from a unique combination of meteorological conditions
associated with the early-January 2013 SSW: unusually low temperatures
in December 2012, offspring vortices within which air remained well
isolated for nearly 1 month after the vortex split, and greater-than-usual vortex sunlight exposure throughout December 2012 and January
2013. Conditions in the two offspring vortices differed substantially,
with the one overlying Canada having lower temperatures, lower nitric
acid (HNO3), lower hydrogen chloride, more sunlight
exposure/higher ClO in late January, and a later onset of chlorine
deactivation than the one overlying Siberia. MLS HNO3 and
CALIPSO data indicate that PSC activity in December 2012 was more
extensive and persistent than at that time in any other Arctic winter in
the past decade. Chlorine monoxide (ClO, measured by MLS) rose earlier
than previously observed and was the largest on record through
mid-January 2013. Enhanced vortex ClO persisted until mid-February
despite the cessation of PSC activity when the SSW started. Vortex
HNO3 remained depressed after PSCs had disappeared; passive
transport calculations indicate vortex-averaged denitrification of about
4 parts per billion by volume. The estimated vortex-averaged chemical ozone loss,
~ 0.7–0.8 parts per million by volume near 500 K (~21 km), was the largest
December/January loss in the MLS record from 2004/05 to 2014/15. |
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