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Ann. Geophys., 20, 1769-1781, 2002
www.ann-geophys.net/20/1769/2002/
© European Geosciences Union 2002
A Statistical study of the Doppler spectral width of high-latitude ionospheric F-region echoes recorded with SuperDARN coherent HF radars
J.-P. Villain1, R. André1, M. Pinnock2, R. A. Greenwald3, and C. Hanuise4,*
1LPCE/CNRS, 3A Av. de la Recherche Scientifique, 45071 Orléans Cedex, France
2British Antarctic Survey, High Cross, Madingley Road, CB3 OET Cambridge, UK
3The Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland, USA
4LSEET/CNRS, Université de Toulon et du Var, BP 132, 83957 La Garde Cedex, France
*now at LPCE/CNRS
Correspondence to: J.-P. Villain (jvillain@cnrs-orleans.fr)
Abstract. The HF radars of the Super Dual Auroral
Radar Network (SuperDARN) provide measurements of the E × B
drift of ionospheric plasma over extended regions of the high-latitude
ionosphere. We have conducted a statistical study of the associated Doppler
spectral width of ionospheric F-region echoes. The study has been conducted
with all available radars from the Northern Hemisphere for 2 specific periods
of time. Period 1 corresponds to the winter months of 1994, while period 2
covers October 1996 to March 1997. The distributions of data points and average
spectral width are presented as a function of Magnetic Latitude and Magnetic
Local Time. The databases are very consistent and exhibit the same features.
The most stringent features are: a region of very high spectral width,
collocated with the ionospheric LLBL/cusp/mantle region; an oval shaped region
of high spectral width, whose equator-ward boundary matches the poleward limit
of the Holzworth and Meng auroral oval. A simulation has been conducted to
evaluate the geometrical and instrumental effects on the spectral width. It
shows that these effects cannot account for the observed spectral features. It
is then concluded that these specific spectral width characteristics are the
signature of ionospheric/magnetospheric coupling phenomena.
Key words. Ionosphere (auroral ionosphere;
ionosphere-magnetosphere interactions; ionospheric irregularities)
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