Ionospheric and Geomagnetic Activity Investigated Using Oblique Sounding Comparisons With an HF Radio Propagation Model

Oblique HF sounder paths over ~2000km have been operating between New Zealand and Australia for a number of years. The maximum observed frequencies (MOF) are compared with predictions from the climatological HF radio skywave propagation model used by IPS. Variations from predicted median (MUF),lower (OWF) and upper decile frequencies may be interpreted in terms of ionospheric and geomagnetic activity and the effectiveness of parameterisation of ionospheric support for HF by the T-index examined. Closely spaced multiple paths provide opportunities to investigate small scale F2 layer structures.