A comparison of middle atmospheric dynamics at Saskatoon (52°N, 107°W) as measured by a medium‐frequency radar and a Fabry‐Perot interferometer

The Saskatoon medium‐frequency radar and a recently installed Fabry‐Perot interferometer were operated together on a continuous basis during the autumn and early winter of 1987. Observations of the atomic oxygen OI 557.7‐nm emission provide Doppler winds from the airglow layer near 97 km. Radar winds are available from 60 to 110 km during daylight hours and from 80 to 110 km at night. A comparison of the two instruments is hampered, as radar data are few in number when auroral contamination of the airglow is minimal. Hence two types of comparisons are made: first, individual radar days and radar 4‐day means are compared with optical winds, and second, extrapolation of the radar's diurnal and semidiurnal tides, which dominate the wind flow of this region, are used to predict the observed nighttime wind field. Generally, the winds are very similar between systems, but differences emerge, stressing the need to avoid auroral contamination of airglow data at relatively high latitudes.