MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Progress in Earth and Planetary Science

Table 1 Radar techniques for investigating the MLT region

Radar technique	Typical frequency (wavelength)	Frequency range	Typical height coverage	Height resolution	Time resolution	Measured quantities	Status
Meteor radar	30 MHz (10 m)	MF to UHF	75–110 km	1–5 km	30–60 min	u, v, T, ρ, radiants, meteoroid velocities	Current
LF ionospheric spaced antenna drift	200 kHz (1500 m)	200 kHz (1500 m)	90–100 km (night)	1 height uncertainty ~2 km	1 min	u, v	Retired
Dedicated DAE/DPE PR radar	3 MHz (100 m)	3 MHz (100 m)	60–90 km (day)	1–3 km	1–5 min	Ne, υ	Retired
Dedicated DAE/DPE PR radar	3 MHz (100 m)	3 MHz (100 m)	85–100 km (night)	1–3 km	1–5 min	Ne, υ	Retired
MF/HF PR SA radar	3 MHz (100 m)	1.94 to 3.18 MHz	60–100 km (day)	1–3 km	1–5 min	u, v, Ne, υ	Current
MF/HF PR SA radar	3 MHz (100 m)	1.94 to 3.18 MHz	80–100 km (night)	1–3 km	1–5 min	u, v, Ne, υ	Current
MST radar	50 MHz (6 m)	44.75 to 64 MHz	0.5–20 km	150–600 m	5 min	u, v, w	Current
MST radar	50 MHz (6 m)	44.75 to 64 MHz	60–80 km (day)	150–600 m	5 min	u, v, w	Current
SuperDARN radar	12 MHz (25 m)	8–20 MHz	As for meteor radar	As for meteor radar	As for meteor radar	As for meteor radar	Current

The symbols represent the following parameters: u is the zonal wind magnitude, v is the meridional wind magnitude, w is the vertical wind magnitude, T is the temperature, ρ is the neutral density, N _e the electron number density, and υ is the collision frequency