Abstract
Utilizing atmospheric temperature observed from Mars Years 33 to 36 by
the Imaging Ultraviolet Spectrograph (IUVS) onboard the Mars Atmosphere
and Volatile Evolution (MAVEN) and Mars Climate Sounder (MCS) onboard
Mars Reconnaissance Orbiter (MRO), we derive the diurnal and semidiurnal
thermal tides from 30 to 160 km. Vertical phase velocities of the
migrating tides indicate their upward propagation above 100 km during
the dust season (solar longitude, Ls 240° to 300°). During the non-dust
season (Ls 30° to 150°), the diurnal eastward wavenumber 2 (DE2) and
wavenumber 3 (DE3) tides can propagate upward from the lower atmosphere
to ~140 km. The seasonal variation of DE2 and DE3
amplitudes in the thermosphere corresponds well to their counterparts in
the lower atmosphere, primarily controlled by their Hough (1,1) modes.
The upward propagation of these tides could potentially impact the
vertical coupling between the Martian lower and upper atmosphere.