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| Titel |
Observations of the ultra-fast Kelvin wave using meteor radar over a Brazilian extra-tropical station |
| VerfasserIn |
Amitava Guharay, Paulo Prado Batista, Barclay Robert Clemesha |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077023
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| Zusammenfassung |
| Characteristics of the equatorial 3.5-day ultra-fast Kelvin (UKF) wave are investigated with four year meteor radar wind observations over Cachoeira Paulista (22.7S, 45W). UFK signature manifests as discrete bursts spanning over various times of the year with generally less amplitude during fall equinox and early winter span. Daily as well as seasonal mean amplitude of the UFK wave is found to be sufficiently smaller than that observed previously from equatorial stations. Estimated vertical wavelength of the UFK wave comes out to be larger than 80 km. Comparison of present results with another Brazilian equatorial station exhibits latitudinal invariance of the wave as well as transient local dynamical influence to its variability. High zonal acceleration caused by momentum flux convergence due to the UFK wave just after equinoxes is supposed to be responsible for driving westerly phase of the mean zonal wind immediately after equinoxes and hence the mesospheric semiannual oscillation. There is a clear signature of modulation of the UFK wave amplitude by various harmonics of the annual oscillation. |
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