Global Seasonal Variations of Martian Atmospheric Pressure and Density From Mars Climate Sounder

Pressure and density are fundamental atmospheric parameters that reflect the mass and thermodynamic structure of the planetary atmosphere. They have a complex spatial distribution and dramatic seasonal variations in the cold, CO 2 ‐dominated Martian atmosphere. However, their seasonal variations on global scales and their quantitative correlations with atmospheric mass, thermal structure and dust activity have not been systematically analyzed. This study uses remotely sensed data from the Mars Climate Sounder to investigate the spatial and temporal variations of the complex Martian atmospheric pressure and density in a global view from the surface to the mesosphere. In the vertical direction, changes in atmospheric pressure and density above 40 km are largely influenced by expansion or contraction effects of the Martian atmosphere in response to annual changes in solar radiation intensity and dust loading, while the atmosphere in the lower 20 km is more sensitive to semiannual variations in total atmospheric mass related to the evolution of the polar ice caps. To quantify the influence of large dust storms on the thermal structure and mesospheric density structure, we applied correlation analysis and found the best correlations for 90‐km density, 35‐km temperature and 23‐km dust. Finally, the quantitative linear relationships between the three are established, which can provide simplified and readily applicable empirical relationship constraints for future modeling studies of the lower thermosphere below 200 km. This is important for future analyses of the upper atmospheric response to dust storms, and also useful for improving the aerobraking design of future Mars exploration missions.