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| Titel |
First observation of quasi-2-day oscillations in ionospheric plasma frequency at fixed heights |
| VerfasserIn |
D. Altadill, J. G. Solé, E. M. Apostolov |
| 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 ; 16, no. 5 ; Nr. 16, no. 5, S.609-617 |
| Datensatznummer |
250013281
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| Publikation (Nr.) |
 copernicus.org/angeo-16-609-1998.pdf |
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| Zusammenfassung |
The existence and development of the
quasi-2-day oscillations in the plasma frequency variations of the F region at
northern middle latitudes are investigated. A new approach to study the
quasi-2-day oscillations is presented, using a methodology that allows us to do
such a study at fixed heights. The hourly values of plasma frequency at fixed
heights, from 170 km to 220 km at 10 km step, obtained at the Observatori de
l'Ebre station (40.8°N, 0.5°E) during 1995 are used for analysis. It is found
that quasi-2-day oscillations exist and persisted in the ionospheric plasma
frequency variations over the entire year 1995 for all altitudes investigated.
The dominant period of oscillation ranges from 42 to 56 h. The amplitude of
oscillation is from 0.1 MHz to 1 MHz. The activity of the quasi-2-day
oscillation is better expressed during the summer half year when several
enhancements, about 15–30 days in duration, were observed. The largest
enhancements of the oscillation occurred during early June, July and early
August; i. e., near and after the summer solstice when the 2-day wave in the
middle neutral atmosphere typically displays its largest activity in the
Northern Hemisphere. The results obtained may help us understand better the
possible influencing mechanisms between the 2-day wave in the middle neutral
atmosphere and the ionospheric quasi-2-day oscillations.
Key words. Ionosphere (Ionosphere - atmosphere
interactions; Mid-latitude ionosphere; Plasma waves and instabilities) |
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