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Titel |
Tropical connection to the polar stratospheric sudden warming through quasi 16-day planetary wave |
VerfasserIn |
C. Vineeth, T. K. Pant, K. K. Kumar, S. G. Sumod |
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 ; 28, no. 11 ; Nr. 28, no. 11 (2010-11-05), S.2007-2013 |
Datensatznummer |
250016906
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Publikation (Nr.) |
copernicus.org/angeo-28-2007-2010.pdf |
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Zusammenfassung |
The Planetary Waves (PWs) are believed to have significant role in
generating the wintertime warming over the polar stratosphere, known as
Stratospheric Sudden Warming (SSW). However, the origin, characteristics and
evolution of these waves are still speculative. The possibility that the PWs
over the polar stratosphere, which play an important role in the generation
of SSW, could also have contribution from the tropics has been indicated
through many numerical simulations in the past, but due to the paucity of
global measurements it could not be established unequivocally. The earlier
numerical studies also indicated the presence of a zero-wind line (more
general the critical layer, where the zonal wind amplitude becomes zero)
whose real counterparts were not observed in the atmosphere. The present
study based on the NCEP/NCAR reanalysis of stratospheric wind and
temperatures of recent years clearly shows that (i) the zero-wind line
appears over the tropics ~60 days prior to the major SSWs and
progresses towards the Pole and (ii) an enhanced PW activity of quasi
periodicity 16-days, which is also seen almost simultaneously with the
zero-wind line, shows a propagation from equator to the Pole. This result is
significant as it presents for the first time the connection between the
tropics during the SSW events and the pole, through the quasi 16-day wave. |
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