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Ann. Geophys., 23, 3451-3455, 2005
www.ann-geophys.net/23/3451/2005/
© European Geosciences Union 2005
A comparison of satellite scintillation measurements with HF radar backscatter characteristics
S. E. Milan1, S. Basu2, T. K. Yeoman1, and R. E. Sheehan3
1Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
2Space Vehicles Directorate, Air Force Research Laboratory, Hanscom Air Force Base, Masachusetts 01731, USA
3Institute for Scientific Research, Boston College, Newton Center, Massachusetts 02467, USA
Abstract. We examine the correspondence between high latitude
ionospheric scintillation measurements made at 250MHz with the occurrence
of 10MHz HF coherent radar backscatter, on 13 and 14 December 2002. We
demonstrate that when the ionospheric intersection point of the
scintillation measurements is co-located with significant HF radar
backscatter, the observed scintillation, quantified by the S4 index, is
elevated. Conversely, when the radar indicates that backscatter is observed
away from the intersection point due to movements of the auroral zone, the
observed scintillation is low. This suggests that scintillation is highly
location-dependent, being enhanced in the auroral zone and being lower at
sub-auroral latitudes. The coexistence of scintillation and HF radar
backscatter, produced by ionospheric density perturbations with scale sizes
of 100s of metres and ~15 m, respectively, suggests that a broad spectrum
of density fluctuations is found in the auroral zone.
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