Villanueva, Geronimo L.Geronimo L.VillanuevaLiuzzi, GiulianoGiulianoLiuzziCrismani, Matteo M. J.Matteo M. J.CrismaniAoki, ShoheiShoheiAokiVandaele, Ann CarineAnn CarineVandaeleDaerden, FrankFrankDaerdenSmith, Michael D.Michael D.SmithMumma, Michael J.Michael J.MummaKnutsen, Elise W.Elise W.KnutsenNeary, LoriLoriNearyViscardy, SebastienSebastienViscardyThomas, Ian R.Ian R.ThomasLopez-Valverde, Miguel AngelMiguel AngelLopez-ValverdeRistic, BojanBojanRisticPatel, Manish R.Manish R.PatelHolmes, James A.James A.HolmesBELLUCCI, GiancarloGiancarloBELLUCCILopez-Moreno, Jose JuanJose JuanLopez-Moreno2025-03-102025-03-1020212375-2548http://hdl.handle.net/20.500.12386/36561Isotopic ratios and, in particular, the water D/H ratio are powerful tracers of the evolution and transport of water on Mars. From measurements performed with ExoMars/NOMAD, we observe marked and rapid variability of the D/H along altitude on Mars and across the whole planet. The observations (from April 2018 to April 2019) sample a broad range of events on Mars, including a global dust storm, the evolution of water released from the southern polar cap during southern summer, the equinox phases, and a short but intense regional dust storm. In three instances, we observe water at very high altitudes (>80 km), the prime region where water is photodissociated and starts its escape to space. Rayleigh distillation appears the be the driving force affecting the D/H in many cases, yet in some instances, the exchange of water reservoirs with distinctive D/H could be responsible.ELETTRONICOenArticle10.1126/sciadv.abc88432-s2.0-85101030875https://www.science.org/doi/10.1126/sciadv.abc8843https://api.elsevier.com/content/abstract/scopus_id/851010308752021SciA....7.8843VFIS/05 - ASTRONOMIA E ASTROFISICA