The SuperDARN HF radars in Saskatoon, Sask. and Kapuskasing, Ont. have been used to measure Doppler velocity spectra of backscatter from the F-layer. A special multipulse sequence was developed to increase the number of measured autocovariance points. These spectra were used to benchmark spectral estimators based on the Fourier Transform and parametric spectral estimators. A parametric spectral estimator using the Burg algorithm improved the resolution of the spectra. A distinct double-peaked spectral signature was found in spatially localized regions. A comparison with particle data as measured by a DMSP satellite suggests a strong spatial correlation of soft-electron precipitation with great variability with the occurrence of the spectral features. Several generating mechanisms for double-peak spectra are suggested, including the Kelvin-Helmholtz instability and precipitation-induced electric fields in arc and ray structures.
I would like to thank Dr. G. Sofko for supporting me financially and
academically throughout my graduate career at the University of Saskatchewan
and during the making of this thesis. He has made it possible for me to
pursue an academic career in Canada after my undergraduate years were
completed and he has given me much freedom during my graduate work.
I would also like to thank all the members of the SuperDARN team here in
Saskatoon for their generous supply of help, advice and encouragement that
is so much needed for a graduate student. I hope to give something back to
them with this thesis.
Finally, I would like to thank my wife Jennifer for putting up with my
continued urge to explain all the details of my research to her -- it has
helped me focus and hopefully do a better job.