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Titel |
The Hiccup: a dynamical coupling process during the autumn transition in the Northern Hemisphere – similarities and differences to sudden stratospheric warmings |
VerfasserIn |
V. Matthias, T. G. Shepherd, P. Hoffmann, M. Rapp |
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. 2 ; Nr. 33, no. 2 (2015-02-23), S.199-206 |
Datensatznummer |
250121163
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Publikation (Nr.) |
copernicus.org/angeo-33-199-2015.pdf |
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Zusammenfassung |
Sudden stratospheric warmings (SSWs) are the most prominent vertical coupling
process in the middle atmosphere, which occur during winter and are caused by
the interaction of planetary waves (PWs) with the zonal mean flow. Vertical
coupling has also been identified during the equinox transitions, and is
similarly associated with PWs. We argue that there is a characteristic aspect
of the autumn transition in northern high latitudes, which we call the
"hiccup", and which acts like a "mini SSW", i.e. like a small minor
warming. We study the average characteristics of the hiccup based on a
superimposed epoch analysis using a nudged version of the Canadian Middle
Atmosphere Model, representing 30 years of historical data. Hiccups can be
identified in about half the years studied. The mesospheric zonal wind
results are compared to radar observations over Andenes (69° N,
16° E) for the years 2000–2013. A comparison of the average
characteristics of hiccups and SSWs shows both similarities and differences
between the two vertical coupling processes. |
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