Simultaneous mesosphere-lower thermosphere and thermospheric F region observations using middle and upper atmosphere radar

The continuous observations, each lasting more than a week, provide simultaneous zonal and meridional wind velocities at MLT altitudes (80–95 km), meridional wind velocity in the upper thermosphere (220–450 km), and electron density and peak height in the ionosphere with a time resolution of 1.5 hours.

The data seem to suggest that the upper atmospheric regions could be dynamically coupled through mean winds, tides, and waves. Diurnal (24-hour) and semidiurnal (12-hour) tides and waves of periods 16–20 hours and 35–55 hours coexist at MLT and upper thermosphere altitudes, and the waves become stronger than tides at mesopause (≈88 km) in both October and March. The data in these equinoctial months also show large differences in mean winds, tides, and waves in the MLT region.