Ionospheric refraction effects in slant range profiles of auroral HF coherent echoes

The theory of auroral coherent echoes developed for VHF scattering by Uspensky et al. (1988, 1989) is applied to the interpretation of intensity and Doppler velocity slant range profiles of HF radar aurora. The theoretical model includes the effects of irregularity aspect sensitivity, ionospheric refraction of the radar beam, and the reception of signals from different heights. The predicted profiles of HF radar aurora are compared with Schefferville HF radar observations in the frequency interval of 9-18 MHz. Satisfactory agreement is found between theory and experiment for the intensity profiles. However, there are significant discrepancies for the Doppler velocity profiles. We discuss this lack of agreement in light of other recent observations.