Large‐Scale Comparison of Polar Cap Ionospheric Velocities Measured by RISR‐C, RISR‐N, and SuperDARN

Abstract The combined fields of view of the two Resolute Bay Incoherent Scatter Radars (RISR‐Canada and RISR‐North) significantly overlap the field of view of the Super Dual Auroral Radar Network (SuperDARN) radar located in Rankin Inlet. These radars measure ionospheric flow velocities in the polar cap region. Velocity data from the first multiple‐day combined operations of the two RISR radars and Rankin Inlet have been compared. Direct comparisons between line‐of‐sight measurements by both types of radars have been performed. These comparisons included data from 40 days of radar operations and used velocity data from 35 SuperDARN range gates (spanning 1,575 km). Overall, 5.2 × 10 5 comparison sets were analyzed. In particular during the daytime, signatures of groundscatter in the SuperDARN data often existed at most of the ranges considered in this comparison. This groundscatter could be partially removed from the comparison by only considering SuperDARN data points that had ionospheric velocity measurements in surrounding range cells. It was found that after removing groundscatter contamination at medium SuperDARN ranges (range gates 18–45), velocities measured by the two radar systems agreed when the high‐frequency results were adjusted to account for the refractive index effect. In regions dominated by groundscatter and E region scatter, lower SuperDARN velocities were measured and the overall comparison with the F region RISR velocities was poor. Key Points Combined FOV of two RISR radars overlaps Rankin SuperDARN ranges from ~600 to ~2,200 km F region velocities measured by SuperDARN are comparable to those measured by RISR after accounting for refractive index When present, E region and ground echoes introduce Doppler shifts that are significantly slower than velocities observed by RISR