Short vertical wavelength gravity waves in the Martian polar lower atmosphere observed by reanalysis of Mars Global Surveyor radio occultation data

This study investigated gravity waves in the Martian polar lower atmosphere using Mars Global Surveyor (MGS) radio occultation data from February 1998 to March 1999. In addition to the conventional geometrical optics method, Full Spectrum Inversion (FSI) was used to achieve a vertical resolution of -300 m in terms of the wavelength. In the polar night in the southern high latitude, wavelike structures with vertical wavelengths ranging from -1 km to several km extend from the surface to high altitudes. The positive static stability near the surface and the high terrain in the southern high latitude suggest the waves were topographically generated. The near-surface wind speed was estimated to be a few m s-1. In the midnight sun in the northern high latitude, waves show smaller amplitudes up to 10-15 km altitudes and attenuation above, which is attributable to reduced background stability. Near-neutral thin layers were ubiquitously observed in both groups, indicating the generation of turbulent layers by saturated gravity waves. It was shown that high-resolution radio occultations with radio holographic analysis offer a valuable tool for understanding atmosphere-solid planet interactions.