Rederivation of the MGS radio occultation measurements in the Martian south polar winter regions using MRO-MCS temperature climatology

Radio occultation (RO), which can probe the thermal structure of a planetary atmosphere, needs information of atmospheric composition and initial temperature at the uppermost point when retrieving the profiles. In the Martian polar winter, the major atmospheric component CO$ _{2}$ condenses to the surface and the atmospheric CO$ _{2}$ depletes, which results in a change of atmospheric composition that affects RO measurements. Noguchi et al. [2014, JGR] estimated the amount of CO$ _{2}$ depletion in the southern polar winter by using GRS-Ar measurements and rederived MGS RO temperature profiles, finding more frequent CO$ _{2}$ supersaturation and a larger degree of supersaturation. Although they also showed that initial temperatures could affect the detection of CO$ _{2}$ supersaturation, they could not utilize reliable initial temperatures based on observations at that time. In the present study, we focus on MRO-MCS observations, which provide a long-term atmospheric dataset spanning more than five Mars Years. We use this multi-year temperature climatology to rederive MGS RO observations. We find even more frequent CO$ _{2}$ supersaturation and larger degrees of supersaturation than shown in Noguchi et al. [2014, JGR].