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| Titel |
The influence of time-dependent wind on gravity-wave propagation in the middle atmosphere |
| VerfasserIn |
L. Zhong, L. J. Sonmor, A. H. Manson, C. E. Meek |
| 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 ; 13, no. 4 ; Nr. 13, no. 4, S.375-394 |
| Datensatznummer |
250011818
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| Publikation (Nr.) |
 copernicus.org/angeo-13-375-1995.pdf |
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| Zusammenfassung |
| Ray-tracing techniques are used to
computationally investigate the propagation of gravity waves through the middle
atmosphere, as characterized by the vertically varying CIRA-86 wind and
temperature models, plus a tidal wind model that varies temporally as well as
vertically. For the wave parameters studied here, the background wind variation
has a much stronger influence on the ray path and changes in wave
characteristics than does the temperature variation. The temporal variation of
the tidal component of the wind changes the observed frequency, sometimes
substantially, while leaving the intrinsic frequency unaltered. It also renders
temporary any critical levels that occur in the tidal region. Different starting
times for the rays relative to the tidal phase provide different propagation
environments, so that the temporary critical levels appear at different heights.
The lateral component of the tidal wind is shown to advect propagating wave
packets; the maximum lateral displacement of a packet varies inversely with its
vertical group velocity. Time-dependent effects are more pronounced in local
winter than in summer. |
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