Atmospheric Tides at High Latitudes in the Martian Upper Atmosphere Observed by MAVEN and MRO

Abstract

AbstractGlobal‐scale waves have been seen throughout the Martian atmosphere and can achieve significant amplitude at higher altitudes. Previous observations of the upper atmosphere have also revealed wavenumber‐3 signatures with significant amplitudes that have been interpreted as signatures of diurnal and semidiurnal tides or stationary planetary waves. This study focuses on two intervals during which concurrent observations of the upper thermosphere made in situ, the middle thermosphere made remotely, and the middle atmosphere made remotely provide observations of the atmospheric tides between 50‐ and 200‐km altitude. Focusing on high latitudes, these observations are able to identify strong wavenumber‐3 signatures in the thermosphere that propagate eastward with increasing local time, consistent with an eastward propagating tide. A complementary analysis of the data from the middle atmosphere reveals wavenumber‐3 signatures that move eastward and upward. During the first interval, these analyses reveal a combination of the diurnal tide DE2 and the semidiurnal tide SE1 to be present, while during the second only the semidiurnal SE1 is seen. During both intervals, the observations provide a consistent picture of these waves being present from the middle atmosphere to the upper thermosphere, consistent with the theory that such waves are generated in the lower atmosphere and propagate upward throughout the entire atmosphere.