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| Titel |
Observational evidence for the generation of a 4-day oscillation in the low-latitude middle atmosphere associated with an anomalous stratospheric cooling |
| VerfasserIn |
V. Deepa, G. Ramkumar, K. K. Kumar |
| 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 ; 25, no. 9 ; Nr. 25, no. 9 (2007-10-02), S.1959-1965 |
| Datensatznummer |
250015910
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| Publikation (Nr.) |
 copernicus.org/angeo-25-1959-2007.pdf |
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| Zusammenfassung |
| Altitude profiles of temperature in the stratosphere and lower mesosphere over
Gadanki (13.5° N, 79.2° E), based on lidar observations during
the Equatorial Wave Study campaign (29 February–2 April 2000), showed an
anomalous cooling of the stratosphere, lasting for about 4–5 days.
Immediately following this stratospheric cooling, a prominent ~4-day
period oscillation is observed in the zonal, as well as meridional wind in the
30–50 km altitude region, obtained from simultaneous rocketsonde and balloon
wind measurements. The amplitude of this wave is in the range of 5–15 ms−1 in
this altitude region. The altitude profiles of phase of this 4-day
oscillation show a constant phase with height indicating that the wave is
not propagating vertically. The causative mechanism for the sudden cooling
is investigated by examining the day-to-day variation in the total
atmospheric column ozone. Zonal and meridional wind components of this
oscillation are approximately in quadrature phase, with zonal wind leading
the meridional wind. Strikingly, while the 4-day wave is clearly observable
in the zonal and meridional winds, it is almost absent in the temperature. |
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