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), we derive the diurnal and semidiurnal
thermal tides from 90 to 160 km. The seasonal variations of diurnal
(DW1) and semidiurnal (SW2) tides in the thermosphere and mesosphere,
observed by the Mars Climate Sounder (MCS), along with vertical phase
velocities, indicate different sources for the migrating tide in the
lower and upper atmosphere. The seasonal variation of diurnal eastward
wavenumber 2 (DE2) tide in the thermosphere corresponds well to its
counterpart in the lower atmosphere. Vertical phase velocities indicate
that the DE2 propagates upward from the lower atmosphere to
~150 km, except near the perihelion (solar longitude
210° to 270°). The upward propagation of this DE2 tide could potentially
impact the vertical coupling between the Martian lower and upper
atmosphere.