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Ann. Geophys., 25, 675-687, 2007
www.ann-geophys.net/25/675/2007/
© European Geosciences Union 2007

Factors determining spectral width of HF echoes from high latitudes

P. V. Ponomarenko, C. L. Waters, and F. W. Menk
University of Newcastle, Callaghan, New South Wales, Australia

Abstract. Spectral width is one of the standard data types produced by the Super Dual Auroral Radar Network (SuperDARN). A pronounced latitudinal gradient in spectral width has been reported in the literature and is used as an empirical proxy for the ionospheric footprint of the open-closed field-line boundary. In this work we investigated the daytime radar echo properties near the spectral width boundary using a multi-frequency sounding regime. We have found that the relatively large spectral width values ≥150 m/s observed poleward of the boundary are produced by ionospheric irregularities with lifetime τ_l≃10–25 ms, which is essentially independent of the scale size. These irregularities are statistically co-located with low-energy (~100 eV) electron precipitation, which may play a major role in producing F-region turbulence above 75 MLAT via restructuring the ionospheric plasma on time scales ~τ_l.

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Citation: Ponomarenko, P. V., Waters, C. L., and Menk, F. W.: Factors determining spectral width of HF echoes from high latitudes, Ann. Geophys., 25, 675-687, 2007.   Bibtex   EndNote   Reference Manager