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Titel |
Variations in the occurrence of SuperDARN F region echoes |
VerfasserIn |
M. Ghezelbash, R. A. D. Fiori, A. V. Koustov |
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 ; 32, no. 2 ; Nr. 32, no. 2 (2014-02-20), S.147-156 |
Datensatznummer |
250121028
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Publikation (Nr.) |
copernicus.org/angeo-32-147-2014.pdf |
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Zusammenfassung |
The occurrence of F region ionospheric echoes observed by a number of
SuperDARN HF radars is analyzed statistically in order to infer solar cycle,
seasonal, and diurnal trends. The major focus is on Saskatoon radar data for
1994–2012. The distribution of the echo occurrence rate is presented in terms of
month of observation and magnetic local time. Clear repetitive patterns are
identified during periods of solar maximum and solar minimum. For years near
solar maximum, echoes are most frequent near midnight during winter. For
years near solar minimum, echoes occur more frequently near noon during
winter, near dusk and dawn during equinoxes and near midnight during summer.
Similar features are identified for the Hankasalmi and Prince George radars
in the northern hemisphere and the Bruny Island TIGER radar in the southern
hemisphere. Echo occurrence for the entire SuperDARN network demonstrates
patterns similar to patterns in the echo occurrence for the Saskatoon radar
and for other radars considered individually. In terms of the solar cycle,
the occurrence rate of nightside echoes is shown to increase by a factor of
at least 3 toward solar maximum while occurrence of the near-noon echoes
does not significantly change with the exception of a clear depression during
the declining phase of the solar cycle. |
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