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| Titel |
Thermospheric gravity waves in Fabry-Perot Interferometer measurements of the 630.0nm OI line |
| VerfasserIn |
E. A. K. Ford, A. L. Aruliah, E. M. Griffin, I. McWhirter |
| 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 ; 24, no. 2 ; Nr. 24, no. 2 (2006-03-23), S.555-566 |
| Datensatznummer |
250015494
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| Publikation (Nr.) |
 copernicus.org/angeo-24-555-2006.pdf |
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| Zusammenfassung |
| Gravity waves are an important feature of mesosphere - lower thermosphere
(MLT) dynamics, observed using many techniques and providing an important
mechanism for energy transfer between atmospheric regions. It is known that
some gravity waves may propagate through the mesopause and reach greater
altitudes before eventually "breaking" and depositing energy. The
generation, propagation, and breaking of upper thermospheric gravity waves
have not been studied directly often. However, their ionospheric
counterparts, travelling ionospheric disturbances (TIDs), have been
extensively studied in, for example, radar data. At high latitudes, it is
believed localised auroral activity may generate gravity waves in-situ.
Increases in sensor efficiency of Fabry-Perot Interferometers (FPIs) located
in northern Scandinavia have provided higher time resolution measurements of
the auroral oval and polar cap atomic oxygen red line emission at 630.0 nm. A
Lomb-Scargle analysis of this data has shown evidence of gravity wave
activity with periods ranging from a few tens of minutes to several hours.
Oscillations are seen in the intensity of the line as well as the
temperatures and line of sight winds. Instruments are located in
Sodankylä, Finland; Kiruna, Sweden; Skibotn, Norway, and Svalbard in the
Arctic Ocean. A case study is presented here, where a wave of 1.8 h
period has a phase speed of 250 ms-1 with a propagation angle of 302°,
and a horizontal wavelength of 1600 km. All the FPIs are co-located with
EISCAT radars, as well as being supplemented by a range of other
instrumentation. This allows the waves found in the FPI data to be put in
context with the ionosphere and atmosphere system. Consequently, the source
region of the gravity waves can be determined. |
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