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| Titel |
Seasonal variations in gravity wave activity at three locations in Brazil |
| VerfasserIn |
B. R. Clemesha, P. P. Batista, R. A. Buriti da Costa, N. Schuch |
| 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 ; 27, no. 3 ; Nr. 27, no. 3 (2009-03-04), S.1059-1065 |
| Datensatznummer |
250016439
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1059-2009.pdf |
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| Zusammenfassung |
| Using the variance in meteor radar winds as a measure of
gravity wave activity, we investigate the temporal variations in gravity
waves at three locations in Brazil: São João do Cariri (7.3° S, 36.4° W),
Cachoeira Paulista (22.7° S, 45.0° W) and Santa Maria (29.7° S, 53.7° W).
The technique used is that of Hocking (2005) which makes it possible to
separate the zonal and meridional components of the fluctuating wind
velocity. We find that the seasonal variation of the fluctuating wind is
similar to that of the amplitude of the diurnal tide, showing a
predominantly semi-annual variation, stronger at Cachoeira Paulista and
Santa Maria than at the quasi-equatorial station, Cariri. Both with respect
to the seasonal trend and shorter term variations, strong coupling between
gravity wave activity and tides is indicated by a remarkably close
correlation between the fluctuating velocity and the vertical shear in the
tidal winds. It is not clear as to whether this is caused by gravity wave
forcing of the tides or whether it results from in situ generation of
gravity waves by tidal wind shear. |
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