CO2 variations in the Martian lower thermosphere from IUVS-MAVEN airglow observations.

UVS-MAVEN limb observations have been performed since 2014. We have
analyzed almost four years of observations focusing on the O(1S) 297.2
nm dayglow emission line. We have developed an automatic methodology to retrieve the CO2 column densities near 80 km, a region difficult to probe by other techniques. We present nearly two Martian years of observations of pressure variations at different latitudes and comparisons with MCD model predictions. Generally, the best agreement is reached following scaling down of the MCD values from 0.3 to 0.8 to fit the observations. This result was previously expected on the basis of model comparisons with ultraviolet occultation measurements. The data used in this study have been downloaded from NASA's Planetary Data.