MERIDIONAL WIND IN THE AURORAL THERMOSPHERE - RESULTS FROM EISCAT ANDWINDII-O(D-1) COORDINATED MEASUREMENTS

Neutral thermospheric winds calculated from European incoherent scatte r (EISCAT) radar data have been compared with winds measured by wind i maging interferometer (WINDII) in O(D-1) emission during 11 passes of the WINDII fields of view near the radar facility. For the eight occas ions when geomagnetic activity was low the average difference in the m eridional winds measured by the two methods is less than 10 m/s. The E ISCAT calculations were done with and without a ''Burnside factor'' of 1.7, and agreement with WINDII is somewhat better when the Burnside f actor is not included. The three passes corresponding to disturbed con ditions show poor agreement. In addition, agreement between EISCAT and WINDII is better when unfiltered EISCAT winds are used, rather than t he 2-hour running mean used in earlier work. This finding suggests tha t the short-term oscillations seen by EISCAT are real oscillations of the neutral atmosphere.