First high-altitude observations of gravity wave ( GW ) -induced CO _ { 2 } density perturbations in the Martian thermosphere retrieved from NASA ’ s NGIMS instrument on board the MAVEN satellite are presented and interpreted using the extended GW parameterization of \citet Yigit_etal08 and the Mars Climate Database as an input .
Observed relative density perturbations between 180–220 km of 20–40 % demonstrate appreciable local time , latitude , and altitude variations .
Modeling for the spatiotemporal conditions of the MAVEN observations suggests that GWs can directly propagate from the lower atmosphere to the thermosphere , produce appreciable dynamical effects , and likely contribute to the observed fluctuations .
Modeled effects are somewhat smaller than the observed but their highly variable nature is in qualitative agreement with observations .
Possible reasons for discrepancies between modeling and measurements are discussed .