Detecting and Characterising atmospheric gravity waves on Mars' atmosphere - Final results using data from OMEGA/Mars Express

Kurzfassung

Atmospheric gravity waves (GWs) are mesoscale atmospheric oscillations that propagate vertically in stable, stratified planetary atmospheres [1], significantly shaping weather and climate by influencing temperature, wind patterns, and cloud formations. In this study, we present preliminary results of GWs in the Martian atmosphere using the High-Resolution Stereo Camera (HRSC) [2] onboard the European Mars Express (MEx) spacecraft [3]. By taking advantage of high-altitude observations (200-800 m/px) with a field of view from limb to limb, we can investigate the morphological and dynamical properties of GWs. Previous studies using the OMEGA instrument [4] were limited by a narrow field of view, preventing them from capturing the full extent of wave packets. We have morphologically characterised the wave packets in the high-altitude observations, considering the number of crests, horizontal wavelength, packet width and length, and orientation. Additionally, we retrieved cloud heights using a new method adapted from [5] that utilises the RGB channels of HRSC to measure the altitudes of waves present in the images. In addition to pairs of high-altitude observations taken 30 minutes apart, we estimated wind speeds by tracking the displacement of features between the two images. Our findings indicate a varied range of altitudes for different cloud types, including water ice clouds ranging from 15-45 km (±5 km error), CO₂ ice clouds from 60-85 km (±5 km error), and dust clouds from 5-10 km (±3 km error). Wind speeds of 5-15 m/s (±10% error) were estimated, and we created regional wind maps across cloud-rich regions (Figure 1). These wind maps reveal the dynamics of mesoscale cloud structures, illustrating how GWs influence wind patterns across the Martian atmosphere. Future research will incorporate OMEGA's spectral data to classify cloud types accurately.