The actual heights of the SuperDARN echoes have never been systematically estimated. The main difficulty is that the HF signals experience a strong ionospheric refraction, so that even accurate angle-of-arrival measurements provide information only on their virtual height. In this study, we use elevation angle data at 10- and 12-MHz frequency bands from Rankin Inlet (RKN) SuperDARN radar to...
Sporadic E-layers are dense thin layers of metallic (Mg+, Fe+, Na+, Ca+) ions of meteoritic origin which may form at altitudes 90-150 km. These structures are important for radio communications and remote sensing applications because they significantly alter propagation of radio waves. A 3D numerical model of high latitude ionosphere has recently been developed at the University of Alberta. We...
The Earth’s ionosphere can be a nuisance for some navigation and communications systems. Knowledge of the state of the ionosphere helps improve the operational capabilities of such systems. The effect of solar eclipses on the state of the ionosphere leading to a significant decrease of the ionization level and thus losses of free electrons has been observed and studied for decades....
This study examines effects of the April 2024 total solar eclipse on ionospheric electron density and HF radio propagation, using multi-instrument observations and the physics-based SAMI3 model (SAMI3: A Model of the Ionosphere). We compare ground-based ionosonde measurements from across North America, including a newly installed station at Wright-Patterson Air Force Base, which was located...
The Radio Receiver Instrument (RRI) on e-POP/Swarm-E detects ground-based HF radio waves. As HF radio waves traverse the ionosphere, variations in ionospheric density influence propagation. Using the Faraday rotation approach with RRI measurements enables the determination of density variations along the propagation path. The high sampling rate of RRI allows for the detection of plasma...
The multiple interferometry links of ICEBEAR have revolutionized how we look at the radar aurora. At first, we confirmed expectations from previous work: strongly field-aligned irregularities , a strong link with auroral indices, a preferred 100 to 110 km altitude range and Doppler shifts normally (not always) slower than the ion-acoustic speed Cs. The latter has stimulated...
Frequent occurrence of ground-scatter (GS) is a common feature of SuperDARN observations. This study extends previously published work on GS by focusing on data collected by the polar cap radars at Inuvik and Clyde River. One of the objectives is to identify data trends affected by electron density variations in the ionosphere. For the F region GS, both radars show strong solar cycle effect...
