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| Titel |
The estimation of D-region electron densities from riometer data |
| VerfasserIn |
J. K. Hargreaves, M. Friedrich |
| 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 ; 21, no. 2 ; Nr. 21, no. 2, S.603-613 |
| Datensatznummer |
250014578
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| Publikation (Nr.) |
 copernicus.org/angeo-21-603-2003.pdf |
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| Zusammenfassung |
At high latitude the hard
electron precipitation associated with auroral activity is a major source of
ionization for the D-region, one consequence being the absorption of radio
waves. Direct measurements of the D-region electron density are not readily
available, however. This paper investigates the relationship between the
electron density at altitudes between 100 and 70 km and the total radio
absorption observed with a riometer, with a view to using the latter to predict
the former. Tables are given of the median electron density corresponding to 1
dB absorption at 27.6 MHz for each hour of the day, and it is shown that at
certain heights the estimates will be accurate to within a factor of 1.6 on 50%
of the occasions. A systematic variation with time of day is probably
associated with a progressive hardening of the typical electron spectrum during
the morning hours. There is also evidence for a seasonal effect possibly due to
seasonal variations of the mesosphere.
Key words. Ionosphere (auroral
ionosphere) – Radio science (ionospheric propagation; instruments and
techniques) |
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