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| Titel |
Intradiurnal wind variations observed in the lower thermosphere over the South Pole |
| VerfasserIn |
Y. I. Portnyagin, J. M. Forbes, E. G. Merzlyakov, N. A. Makarov, S. E. Palo |
| 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 ; 18, no. 5 ; Nr. 18, no. 5, S.547-554 |
| Datensatznummer |
250013988
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| Publikation (Nr.) |
 copernicus.org/angeo-18-547-2000.pdf |
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| Zusammenfassung |
The first meteor radar measurements of
meridional winds in the lower thermosphere (about 95 ± 5 km), along four
azimuth directions: 0°, 90°E, 180° and 90°W; approximately 2° from the
geographic South Pole were made during two observational campaigns: January 19,
1995-January 26, 1996, and November 21, 1996-January 27, 1997. Herein we report
analyses of the measurement results, obtained during the first campaign, which
cover the whole one-year period, with particular emphasis on the transient
nature and seasonal behavior of the main parameters of the intradiurnal wind
oscillations. To analyze the data, two complementary methods are used: the
well-known periodogram (FFT) technique and the S-transform technique. The
most characteristic periods of the intradiurnal oscillations are found to be
rather uniformly spread between about 7 h and 12 h. All of these oscillations
are westward-propagating with zonal wave number s=1 and their usual
duration is confined to several periods. During the austral winter season the
oscillations with periods less than 12 h are the most intensive, while during
summer season the 12-h oscillations dominate. Lamb waves and internal-gravity
wave propagation, non-linear interaction of the short-period tides, excitation
in situ of the short period waves may be considered as possible processes which
are responsible for intradiurnal wind oscillations in the lower thermosphere
over South Pole.
Key words: Meteorology and atmospheric dynamics (middle
atmosphere dynamics; thermospheric dynamics; waves and tides) |
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