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| Titel |
Coupling in the middle atmosphere related to the 2013 major sudden stratospheric warming |
| VerfasserIn |
R. J. Wit, R. E. Hibbins, P. J. Espy, E. A. Hennum |
| 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 ; 33, no. 3 ; Nr. 33, no. 3 (2015-03-11), S.309-319 |
| Datensatznummer |
250121174
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| Publikation (Nr.) |
 copernicus.org/angeo-33-309-2015.pdf |
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| Zusammenfassung |
| The previously reported observation of anomalous eastward gravity wave
forcing at mesopause heights around the onset of the January 2013 major
sudden stratospheric warming (SSW) over Trondheim, Norway (63° N,
10° E), is placed in a global perspective using Microwave Limb
Sounder (MLS) temperature observations from the Aura satellite. It is shown
that this anomalous forcing results in a clear cooling over Trondheim about
10 km below mesopause heights. Conversely, near the mesopause itself,
where the gravity wave forcing was measured, observations with meteor radar,
OH airglow and MLS show no distinct cooling. Polar cap zonal mean
temperatures show a similar vertical profile. Longitudinal variability in the
high northern-latitude mesosphere and lower thermosphere (MLT) is characterized by a quasi-stationary wave-1
structure, which reverses phase at altitudes below ~ 0.1 hPa.
This wave-1 develops prior to the SSW onset, and starts to propagate westward
at the SSW onset. The latitudinal pole-to-pole temperature structure
associated with the major SSW shows a warming (cooling) in the winter
stratosphere (mesosphere) which extends to about 40° N. In the
stratosphere, a cooling extending over the equator and far into the summer
hemisphere is observed, whereas in the mesosphere an equatorial warming is
noted. In the Southern Hemisphere mesosphere, a warm anomaly overlaying a
cold anomaly is present, which is shown to propagate downward in time. This
observed structure is in accordance with the temperature perturbations
predicted by the proposed interhemispheric coupling mechanism for cases of
increased winter stratospheric planetary wave activity, of which major SSWs
are an extreme case. These results provide observational evidence for the
interhemispheric coupling mechanism, and for the wave-mean flow interaction
believed to be responsible for the establishment of the anomalies in the
summer hemisphere. |
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