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| Titel |
Differences in Arctic and Antarctic PSC occurrence as observed by lidar in Ny-Ålesund (79° N, 12° E) and McMurdo (78° S, 167° E) |
| VerfasserIn |
M. Maturilli, R. Neuber, P. Massoli, F. Cairo, A. Adriani, M. L. Moriconi, G. Donfrancesco |
| 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 ; 5, no. 8 ; Nr. 5, no. 8 (2005-08-09), S.2081-2090 |
| Datensatznummer |
250003026
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| Publikation (Nr.) |
 copernicus.org/acp-5-2081-2005.pdf |
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| Zusammenfassung |
| The extent of springtime Arctic ozone loss does not reach Antarctic ``ozone
hole'' dimensions because of the generally higher temperatures in the
northern hemisphere vortex and consequent less polar stratospheric cloud
(PSC) particle surface for heterogeneous chlorine activation. Yet, with
increasing greenhouse gases stratospheric temperatures are expected to
further decrease. To infer if present Antarctic PSC occurrence can be
applied to predict future Arctic PSC occurrence, lidar observations from
McMurdo station (78° S, 167° E) and NyÅlesund (79° N,
12° E) have been analysed for the 9 winters between 1995 (1995/1996) and
2003 (2003/2004). Although the statistics may not completely cover the
overall hemispheric PSC occurrence, the observations are considered to
represent the main synoptic cloud features as both stations are mostly
situated in the centre or at the inner edge of the vortex. Since the focus
is set on the occurrence frequency of solid and liquid particles, the
analysis has been restricted to volcanic aerosol free conditions. In
McMurdo, by far the largest part of PSC observations is associated with NAT
PSCs. The observed persistent background of NAT particles and their
potential ability to cause denoxification and irreversible denitrification
is presumably more important to Antarctic ozone chemistry than the scarcely
observed ice PSCs. Meanwhile in Ny-Ålesund, ice PSCs have never been
observed, while solid NAT and liquid STS clouds both occur in large
fraction. Although they are also found solely, the majority of observations
reveals solid and liquid particle layers in the same profile. For the
Ny-Ålesund measurements, the frequent occurrence of liquid PSC particles
yields major significance in terms of ozone chemistry, as their chlorine
activation rates are more efficient.
The relationship between temperature, PSC formation, and denitrification is
nonlinear and the McMurdo and Ny-Ålesund PSC observations imply that for
predicted stratospheric cooling it is not possible to directly apply current
Antarctic PSC occurrence to the Arctic stratosphere. Future Arctic PSC
occurrence, and thus ozone loss, is likely to depend on the shape and
barotropy of the vortex rather than on minimum temperature alone. |
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