Seasonal and Dust‐Related Variations in the Dayside Thermospheric and Ionospheric Compositions of Mars Observed by MAVEN/NGIMS

Abstract

The Martian upper atmosphere is the reservoir region for an atmospheric escape to space. The escape rates of O 2 + , O + , and CO 2 + ions of Martian origin and their relative ratios have been measured by ion mass spectrometers aboard Mars Express (e.g.,

Alternate oscillations of Martian hydrogen and oxygen upper atmospheres during a major dust storm

“…The Mars Express/Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars data derived from ref. 16 are stored at https://data.mendeley.com/datasets/vx4gks6bx7/1, and we would like to thank the authors for making their dataset publicly available. The Hisaki disk average airglow brightness data generated in this study is provided in Supplementary Data 1.…”

“…global/regional dust storms [14][15][16] . This is of interest because oxygen atoms, which are mainly produced by CO 2 photodissociation in the upper atmosphere, may be affected by the change in the vertical water distribution during major dust storms.…”

Variations in Vertical CO/CO2 Profiles in the Martian Mesosphere and Lower Thermosphere Measured by the ExoMars TGO/NOMAD: Implications of Variations in Eddy Diffusion Coefficient

“…A substantial variation of the homopause altitude changes the boundary altitude above which gases are diffusively separated according to their mass by molecular diffusion. Therefore, the location of the homopause altitude and eddy diffusion coefficient in that region are important for the thermospheric composition (Yoshida et al, 2020(Yoshida et al, , 2021 and the subsequent escape of species to space. Meanwhile, the homopause altitude and the eddy diffusion coefficient at that altitude have been estimated using the atmospheric composition in the thermosphere observed by the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, which cannot observe the mesosphere regularly.…”

Effect of the 2018 Martian Global Dust Storm on the Main Species in the Upper Ionosphere: Observations and Simulations

“…Yoshida et al. (2021) analyzed the effects of a regional dust storm on different ion densities at ∼200 km. Compared with those two studies, Fang et al.…”

“…Stone et al (2020) researched the possible effect of dust storms on driving water loss based on the observations on H 2 O + in the upper ionosphere. Yoshida et al (2021) analyzed the effects of a regional dust storm on different ion densities at ∼200 km. Compared with those two studies, Fang et al (2020) and Niu et al (2021) are what we are most interested in because they focus more on the behaviors of dominant ion species during global dust storms, which can cause more drastic changes in the upper ionosphere than regional dust storms.…”