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All available data of the thermospheric wind meridional component, deduced from the red line OID Doppler shift as measured by WTNDII on board UARS, have been sorted to plot their averaged diurnal variations. A comparison is presented here of these variations of the poleward wind for high solar flux and mid latitude, at each season, with similar diurnal variations deduced from the set of IS radar data obtained at Saint-Santin.

For its last experiment, the incoherent scatter radar at Saint-Santin measured the ion temperature and the meridional wind, between altitudes 95 and 140km, during the period 21–25 September 1987 of the LTCS-1 campaign. The data have been analyzed in terms of semidiurnal tides. The deduced amplitudes and phases are compared with other incoherent scatter radar measurements made over the American sector of longitude during the same campaign [ Salah et al . (1991) J. geophys. Res. 96, 1071], with the self-consistent global empirical description of the E -region tidal dynamics established from these measurements by Forbes and Salah [(1991) J. geophys. Res. 96, 1155] and with the theoretical predictions of global monthly averaged semidiurnal temperatures and winds presented by Forbes and Vial [(1991) J. geophys. Res. 96, 1147].

The MICADO instrument has been built to measure temperature and wind in the E - and F -regions. It employs a thermally stable field-compensated Michelson interferometer to allow wind measurements. During the winter of 1988–1989, the MICADO instrument was operated at Sodankyla (67°22′N, Finland). Measurements were made by observing the O 1 S (low thermosphere) and the O 1 D lines (high thermosphere) emission. Two co-ordinated campaigns were organized with the EISCAT radar, which operated in special modes. Neutral wind and temperature are derived from EISCAT data. Results of the two instruments are shown. The differences between the two sets of results are discussed and show that most of the discrepancy is due to the presence of vertical winds during the observations where the magnetic activity was high.

Optical observations of the ionosphere above St. Santin de Maurs, made concurrently with Thomson scattering soundings, confirm that the pre-dawn enhancement of the oxygen red lines in the night airglow occurs in synchronism with electronic heating in the F -region at times of sunrise in the magnetically conjugate area. A preliminary calculation indicates photoelectron impact is directly responsible for excitation of O ( 1 D ).