Meridional wind in the auroral thermosphere: Results from EISCAT and WINDII‐O(1D) coordinated measurements

Abstract

Neutral thermospheric winds calculated from European incoherent scatter (EISCAT) radar data have been compared with winds measured by wind imaging interferometer (WINDII) in O(1D) emission during 11 passes of the WINDII fields of view near the radar facility. For the eight occasions when geomagnetic activity was low the average difference in the meridional winds measured by the two methods is less than 10 m/s. The EISCAT calculations were done with and without a “Burnside factor” of 1.7, and agreement with WINDII is somewhat better when the Burnside factor is not included. The three passes corresponding to disturbed conditions show poor agreement. In addition, agreement between EISCAT and WINDII is better when unfiltered EISCAT winds are used, rather than the 2‐hour running mean used in earlier work. This finding suggests that the short‐term oscillations seen by EISCAT are real oscillations of the neutral atmosphere.