Comparison of SuperDARN irregularity drift measurements and F-region ion velocities from the resolute bay ISR

► PolarDARN HF radars measurements contain a mixture of E and F region echoes. ► The F region HF Doppler velocities are given by the cosine component of the EXB drift. ► The E region HF echoes are excited when the magnitude of the EXB drift exceeds a threshold. ► Assumption of FAI-EXB drift equivalence will underestimate ionospheric circulation.