Water Vapor Vertical Distribution on Mars After Six Years of TGO/NOMAD Solar Occultations: 2. Cross‐Validation Within TGO and Comparison With MPCM
Year: 2026
Type: article
Abstract: This is the second part of an investigation of water vapor in the Martian atmosphere using solar occultation observations by the Nadir and Occultation for MArs Discovery (NOMAD) spectrometer on board the ExoMars Trace Gas Orbiter. Following the analysis of six Earth years of NOMAD observations performed in the first part, a cross‐validation between NOMAD and ACS results is presented, showing global as well as profile‐by‐profile comparisons. The results reveal an overall good agreement between different teams and instruments, taking into account the different retrieval methodologies. In order to compare with model predictions, we perform an exhaustive analysis of the water vapor simulated by Mars Planetary Climate Model (MPCM). It shows that the MPCM reproduces most of the water vapor climatological features observed in the atmosphere. However, several discrepancies between model and observations are noticed. Some of these are possibly related to the vertical distribution of dust and its effect on the global circulation and on the water vapor vertical transport. Other data‐model differences found at 60 km seem to be related to discrepancies on the water ice cloud formation in the MPCM. We include a cluster analysis of Martian water vapor vertical profiles for the first time. This technique applied to MPCM and NOMAD water vapor retrievals reveal distinct groups of profiles being representative of specific seasons and latitudinal regions, similarly distributed in both model and observations. Moreover, it allows us to provide a simplified water vapor climatology, useful to detect out‐of‐season events and biases in the retrieval processes.
DOI: 10.1029/2025je009191
Institutions: Consejo Superior de Investigaciones Científicas, Instituto de Astrofísica de Andalucía, The University of Tokyo, Tohoku University, Space Research Institute, Laboratoire de Météorologie Dynamique, Royal Belgian Institute for Space Aeronomy, Institute for Basic Science, Goddard Space Flight Center, The Open University, Institute for Space Astrophysics and Planetology
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: G1274262131, New isotope obervations of Mars atmsopheric evolution: International collaboration of European and Japanese Mars exploration missions, G1433649692, G1965176878, Evolution of carbon and nitrogen and generation of prebiotic molecules in the Martian atmosphere, G250671844, G268798987, 探査機・望遠鏡観測による火星の鉛直水輸送過程解明, Water transport through clouds: development of non-equilibrium planetary cloud physics, G5891631864, G6073717900, G6442527111, G6790863631, G840240675, G919696251
OpenAlex ID: W7128501479