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Titel |
Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar |
VerfasserIn |
N. Swarnalingam, W. K. Hocking, P. S. Argall |
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 ; 27, no. 4 ; Nr. 27, no. 4 (2009-04-07), S.1643-1656 |
Datensatznummer |
250016488
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Publikation (Nr.) |
copernicus.org/angeo-27-1643-2009.pdf |
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Zusammenfassung |
The Resolute Bay VHF radar, located in Nunavut, Canada (75.0° N,
95.0° W) and operating at 51.5 MHz, has been used to investigate
Polar Mesosphere Summer Echoes (PMSE) since 1997. PMSE are a unique
form of strong coherent radar echoes, and their understanding has
been a challenge to the scientific community since their discovery more
than three decades ago. While other high latitude radars have recorded strong
levels of PMSE activities, the Resolute Bay radar has observed
relatively lower levels of PMSE strengths. In order to derive
absolute measurements of PMSE strength at this site, a technique is
developed to determine the radar efficiency using cosmic (sky) noise
variations along with the help of a calibrated noise source. VHF
radars are only rarely calibrated, but determination of efficiency
is even less common. Here we emphasize the importance of efficiency
for determination of cross-section measurements. The significant
advantage of this method is that it can be directly applied to any
MST radar system anywhere in the world as long as the sky noise
variations are known. The radar efficiencies for two on-site radars
at Resolute Bay are determined. PMSE backscatter cross-section is
estimated, and decade-long PMSE strength variations at this location
are investigated. It was noticed that the median of the backscatter
cross-section distribution remains relatively unchanged, but over
the years a great level of variability occurs in the high power tail
of the distribution. |
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