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Abstract

This paper describes comparisons between airglow and meteor radar winds from two co-located wind measuring instruments, a meteor radar and field widened Michelson interferometer (the E-Region Wind Interferometer, ERWIN) and the interpretation of the results. These instruments are located at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nu, Canada (80 N, 86 W). ERWIN provides winds from three nightglow emissions (the oxygen green line (557.7 nm) at ~97 km, an O2 line (866 nm) at ~94 km, and an OH line (843 nm) at ~87 km) on a ~5 minute cadence and an accuracy of ~1 , ~4 and ~1 m/s respectively. The meteor radar and ERWIN have very different temporal and spatial observational footprints. The meteor radar typically provides winds determined on a 60-minute cadence and a 3 km height resolution from a spatial region of ~300 km diameter and ~16 km depth whereas the ERWIN winds are airglow weighted winds from four volumes of ~6 km in height by 6 km radius. After time averaging the ERWIN winds and vertically averaging the radar winds, the winds are found to be strongly correlated. Linear fits indicate that the zero winds of the two techniques agree to ~ 1m/s with the meteor radar exhibiting greater variability than ERWIN. Directional comparisons indicate that the winds are in the same direction but the difference is primarily in the amplitudes. Possible explanations for this discrepancy are described but further work is required to cleanly identify the source of the amplitude difference.