Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 25, 675-687, 2007
© Author(s) 2007. This work is distributed
under the Creative Commons Attribution 3.0 License.
29 Mar 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 τl≃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 ~τl.

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, doi:10.5194/angeo-25-675-2007, 2007.
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