D-region measurements with the differential-absorption, differential-phase partial-reflection experiments

Measurements of the differential phase of partial reflections over a limited height range (60–75 km) have been made simultaneously with the differential amplitude measurements normally made at Ottawa (45°N, 76°W) on a frequency of 2.66 MHz. The addition of the differential-phase data provides a means of measuring the collision frequency in the lower D region that is independent of differential-amplitude measurements in the region where differential absorption is negligible. The two types of measurement have been found to be in satisfactory agreement. Furthermore, the simultaneous measurement of differential phase and amplitude provides a means of investigating the nature of the irregularities causing the partial reflections. It is concluded that these are predominantly irregularities in the electron density in the region.