Yoshida, NaoNaoYoshidaNakagawa, HiromuHiromuNakagawaAoki, ShoheiShoheiAokiErwin, JustinJustinErwinVandaele, Ann CarineAnn CarineVandaeleDaerden, FrankFrankDaerdenThomas, IanIanThomasTrompet, LoïcLoïcTrompetKoyama, ShungoShungoKoyamaTerada, NaokiNaokiTeradaNeary, LoriLoriNearyMurata, IsaoIsaoMurataVillanueva, GeronimoGeronimoVillanuevaLiuzzi, GiulianoGiulianoLiuzziLopez-Valverde, Miguel AngelMiguel AngelLopez-ValverdeBrines, AdrianAdrianBrinesModak, AshimanandaAshimanandaModakKasaba, YasumasaYasumasaKasabaRistic, BojanBojanRisticBELLUCCI, GiancarloGiancarloBELLUCCILópez-Moreno, José JuanJosé JuanLópez-MorenoPatel, ManishManishPatel2025-02-072025-02-0720220094-8276http://hdl.handle.net/20.500.12386/35843Using the Nadir and Occultation for MArs Discovery instrument aboard Trace Gas Orbiter, we derived the CO/CO2 profiles between 75 and 105 km altitude with the equivalent width technique. The derived CO/CO2 profiles showed significant seasonal variations in the southern hemisphere with decreases near perihelion and increases near aphelion. The estimation of the CO/CO2 profiles with a one-dimensional photochemical model shows that an altitude-dependent eddy diffusion coefficient better reproduces the observed profiles than a vertically uniform one. Our estimation suggests that the eddy diffusion coefficient in Ls = 240–270 is uniformly larger by a factor of ∼2 than that in Ls = 90–120 in the southern hemisphere, while they are comparable in the northern hemisphere. This fact demonstrates that the eddy diffusion coefficient is variable with season and latitude.STAMPAenArticle10.1029/2022GL0984852-s2.0-85131290263https://api.elsevier.com/content/abstract/scopus_id/85131290263https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL098485FIS/05 - ASTRONOMIA E ASTROFISICA