Research of internal gravity waves in the Martian atmosphere based on Tianwen-1 and MGS occultation data

Internal gravity waves (IGWs) are critical in driving Martian atmospheric motions and phenomena. This study investigates Martian IGWs using high-resolution data from China's Tianwen-1 mission and NASA's Mars Global Surveyor (MGS) by radio occultation (RO) technique. Key IGW parameters, such as vertical and horizontal wavelengths, intrinsic frequency, and energy densities are extracted based on vertical temperature profiles from the Martian surface to ~50 km altitude. Data reveal that the Martian IGWs we analyze are predominantly small-scale waves, with vertical wavelengths between 6 to 13 km and horizontal wavelengths extending to thousands of kilometers. These waves propagate almost vertically and exhibit low intrinsic frequencies close to the inertial frequency, characteristic of low-frequency inertial IGWs. Tianwen-1 data indicate stronger IGW activity, higher energy densities, and less dissipation than MGS data in the northern hemisphere. In contrast, MGS data in the southern hemisphere show higher buoyancy frequencies and lower vertical wavelengths, suggesting more stable atmospheric conditions conducive to IGW propagation. These extracted IGW characteristics can enhance our understanding of atmospheric dynamics on Mars and contribute valuable information for parameterization in global circulation models.