Atmospheric Gravity Waves in Mars' Lower Atmosphere: Nadir Observations From OMEGA/Mars Express Data

Abstract

We present the detection and characterization of mesoscale waves on the lower clouds of Mars (20–40 km) using hyperspectral images from the Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité (OMEGA) onboard the European Mars Express space mission. We used image navigation and processing techniques based on contrast enhancement and geometrical projections to semi-manually detect and manually characterize morphological properties of the detected waves, such as horizontal wavelength or packet length. Our study covers 3 Martian years, spanning from January 2004 (Mars Year 26) to January 2010 (Mars Year 29). We detected 263 wave packets, of which we characterized 125, revealing an average horizontal wavelength of 21 km, with detected waves spanning horizontal wavelengths between 6 and 83 km. Wave activity exhibited spatial and temporal variability, with larger wave packets concentrated in the northern hemisphere and most detections occurring during daytime. Seasonal patterns revealed higher wave activity during northern spring and autumn and southern winter, linked to regional topography, atmospheric density perturbations, and diurnal heating cycles. These findings provide insights into Martian atmospheric gravity waves and demonstrate the OMEGA data set's value for future studies of Mars's atmospheric dynamics.