Martian atmospheric tides revealed from MAVEN and MCS Observations

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.