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| Titel |
Evidence for thermospheric gravity waves in the southern polar cap from ground-based vertical velocity and photometric observations |
| VerfasserIn |
J. L. Innis, P. A. Greet, P. L. Dyson |
| 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 ; 19, no. 5 ; Nr. 19, no. 5, S.533-543 |
| Datensatznummer |
250014252
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| Publikation (Nr.) |
 copernicus.org/angeo-19-533-2001.pdf |
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| Zusammenfassung |
Zenith-directed Fabry-Perot
Spectrometer (FPS) and 3-Field Photometer (3FP) observations of the
λ630 nm emission (~240 km altitude) were obtained at Davis
station, Antarctica, during the austral winter of 1999. Eleven nights of
suitable data were searched for significant periodicities common to vertical
winds from the FPS and photo-metric variations from the 3FP. Three wave-like
events were found, each of around one or more hours in duration, with periods
around 15 minutes, vertical velocity amplitudes near 60 ms–1 ,
horizontal phase velocities around 300 ms–1 , and horizontal
wavelengths from 240 to 400 km. These characteristics appear consistent with
polar cap gravity waves seen by other workers, and we conclude this is a likely
interpretation of our data. Assuming a source height near 125 km altitude, we
determine the approximate source location by calculating back along the wave
trajectory using the gravity wave property relating angle of ascent and
frequency. The wave sources appear to be in the vicinity of the poleward border
of the auroral oval, at magnetic local times up to 5 hours before local magnetic
midnight.
Key words. Meteorology and
atmospheric dynamics (thermospheric dynamics; waves and tides) |
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