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| Titel |
Initial backscatter occurrence statistics from the CUTLASS HF radars |
| VerfasserIn |
S. E. Milan, T. K. Yeoman, Mark Lester, E. C. Thomas, T. B. Jones |
| 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 ; 15, no. 6 ; Nr. 15, no. 6, S.703-718 |
| Datensatznummer |
250012830
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| Publikation (Nr.) |
 copernicus.org/angeo-15-703-1997.pdf |
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| Zusammenfassung |
| A statistical study of the occurrence of
ground and ionospheric backscatter within the fields-of-view of the CUTLASS HF
radars, at an operating frequency of 10 MHz, during the first 20 months of
operation has been undertaken. The diurnal variation of the occurrence of
backscatter and the range at which such backscatter is observed is found to be
highly dependent on seasonal changes of the ionospheric electron density in both
the E and F region, determined from ionosonde observations. In general,
ionospheric backscatter is observed at far ranges during the local day in winter
months and at near ranges during the local night in summer months. The Iceland
radar observes more near-range E region backscatter than the Finland radar as a
consequence of its more zonal look-direction. The dependence of the occurrence
of backscatter on geomagnetic activity and radar operating frequency are also
investigated. The occurrence of ground and ionospheric backscatter is discussed
in terms of HF propagation modes and ionospheric electron densities as well as
geophysical processes. A brief assessment of the possible impact of solar cycle
variations on the observations is made and frequency management is discussed.
Such a study, with its focus on the `instrumental' aspect of backscatter
occurrence, is essential for a full interpretation of HF coherent radar
observations. |
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