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| Titel |
Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003 |
| VerfasserIn |
A. Engel, T. Möbius, H.-P. Haase, H. Bönisch, T. Wetter, U. Schmidt, I. Levin, T. Reddmann, H. Oelhaf, G. Wetzel, K. Grunow, N. Huret, M. Pirre |
| 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 ; 6, no. 1 ; Nr. 6, no. 1 (2006-02-01), S.267-282 |
| Datensatznummer |
250003309
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| Publikation (Nr.) |
 copernicus.org/acp-6-267-2006.pdf |
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| Zusammenfassung |
| During several balloon flights inside the Arctic polar vortex in
early 2003, unusual trace gas distributions were observed, which
indicate a strong influence of mesospheric air in the
stratosphere. The tuneable diode laser (TDL) instrument SPIRALE
(Spectroscopie Infra-Rouge par Absorption de Lasers Embarqués)
measured unusually high CO values (up to 600 ppb) on 27 January
at about 30 km altitude. The cryosampler BONBON sampled air
masses with very high molecular Hydrogen, extremely low SF6
and enhanced CO values on 6 March at about 25 km altitude.
Finally, the MIPAS (Michelson Interferometer for Passive
Atmospheric Sounding) Fourier Transform Infra-Red (FTIR)
spectrometer showed NOy values which are significantly higher
than NOy* (the NOy derived from a correlation
between N2O and NOy under undisturbed conditions),
on 21 and 22 March in a layer centred at 22 km altitude. Thus,
the mesospheric air seems to have been present in a layer
descending from about 30 km in late January to 25 km altitude in
early March and about 22 km altitude on 20 March. We present
corroborating evidence from a model study using the KASIMA
(KArlsruhe SImulation model of the Middle Atmosphere) model that
also shows a layer of mesospheric air, which descended into the
stratosphere in November and early December 2002, before the minor
warming which occurred in late December 2002 lead to a descent of
upper stratospheric air, cutting off a layer in which mesospheric
air is present. This layer then descended inside the vortex over
the course of the winter. The same feature is found in trajectory
calculations, based on a large number of trajectories started in
the vicinity of the observations on 6 March. Based on the
difference between the mean age derived from SF6 (which has
an irreversible mesospheric loss) and from CO2 (whose
mesospheric loss is much smaller and reversible) we estimate that
the fraction of mesospheric air in the layer observed on 6 March,
must have been somewhere between 35% and 100%. |
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