Martian High-Frequency Gravity Waves Observed by Zhurong and Perseverance Rovers Before and After a Regional Dust Storm

Abstract

This study investigated high-frequency gravity waves (HFGWs) with periods below 20 min observed by the Zhurong/Tianwen-1 and Perseverance/Mars 2020 rovers between local time 09:00 and 11:00, from Ls 140°–165° in Mars Year 36. By analyzing the eccentricity of monochromatic wind perturbations in the horizontal wind data, HFGWs were identified via their predominantly linear characteristics in hodographs. The propagation directions of these waves were determined using polarization relationships from the linear theory of HFGWs. The occurrence of HFGWs doubled following the onset of a regional dust storm in the Utopia Planitia where the Zhurong rover landed. The HFGWs observed by Zhurong predominantly propagated in a north-south direction before the dust storm and then shifted into an east–west direction afterward. In this study, the temperature and wind simulations from the Mars Planetary Climate Model were used to estimate atmospheric instability by calculating the Richardson number before and after the dust storm in the locations of both rovers. As the dust storm developed, intensified dust fronts moved northward from the tropical region and modulated atmospheric instability to the south of Zhurong, which may be responsible for the decrease in wave propagation along the north-south direction.