Study of the hydrogen escape rate at Mars during martian years 28 and 29 from comparisons between SPICAM/Mars express observations and GCM-LMD simulations

Chaufray, Jean‐Yves; González‐Galindo, Francisco; López‐Valverde, M. Á.; Forget, F.; Quémerais, Éric; Bertaux, Jean-Loup; Montmessin, Franck; Chaffin, Michael; Schneider, Nicholas M.; Clarke, J. T.; Leblanc, François; Modolo, Ronan; Yelle, R. V.

doi:10.1016/j.icarus.2019.113498

Cited by 29 publications

(32 citation statements)

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“…Using case 1 profiles does not change the results, in that case, the best fit is also obtained without deuterium and the derived hydrogen density at 200 km is between 0.8 and 1.4 × 10 5 cm −3 . This density is lower than the density derived from the other periods near southern summer, as expected from the seasonal variations of the hydrogen density (Bhattacharyya et al., 2017; Chaffin et al., 2014; Chaufray et al., 2021).…”

Section: Resultsmentioning

confidence: 57%

“…The derived range of D/H at 80 km is between 0.6 and 3.7 × 10 −3 respectively, lower than the derived D/H ratio during period 1, but in the range of the D/H ratio measured during period 2 and in Martian water vapor. The derived hydrogen density at 200 km, between 0.6 and 4.5 × 10 6 cm −3 , is larger than the simulated hydrogen density (Chaufray et al., 2018) which could be attributed to a larger amount of water vapor at high altitudes during this season (Chaufray et al., 2021).…”

Section: Resultsmentioning

confidence: 73%

“…The derived hydrogen density at 200 km, between 2.2 and 4.8 × 10 5 cm −3 is larger than the simulated hydrogen density, considering the ballistic transport in the exosphere, by Chaufray et al (2018) for solar average conditions near Ls = 270° on the dayside. This difference could be due to a larger amount of water vapor at high altitudes during this season (Chaufray et al, 2021). The derived exobase hydrogen and deuterium densities are lower than those derived from period 1 or period 4 (see Section 6.4).…”

Section: Period 2: September 2018mentioning

confidence: 73%

“…Recently, it has been suggested that near southern summer, most of the atomic hydrogen in the upper atmosphere could come from water vapor dissociation in the Martian mesosphere/thermosphere (Chaffin et al, 2017. In this case, the hydrogen density profile could be close to perfect mixing with CO 2 between 80 and 120 km (Chaufray et al, 2021;Krasnopolsky 2019). Therefore, we have performed a set of simulations, solving the diffusion equation as done by Chaufray et al (2008) but without imposing a constant density below 120 km (case 1).…”

Section: Figurementioning

confidence: 99%

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Estimate of the D/H Ratio in the Martian Upper Atmosphere from the Low Spectral Resolution Mode of MAVEN/IUVS

et al. 2021

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Estimating the water escape rate throughout Mars' history depends strongly on the water reservoirs available to exchange with the atmosphere, and the timescale for that exchange. The D/H ratio in a planetary atmosphere is a key parameter for diagnosing water loss from a planet. Hydrogen and deuterium atoms can escape through a variety of processes that need to be constrained to accurately estimate present and past water loss rates (e.g., Cangi et al., 2020). On Mars, the globally averaged D/H ratio is five times larger than that measured in the terrestrial oceans (Encrenaz et al., 2018;Owen et al., 1988;Vandaele & Korablev, 2019). The deuterium enrichment on Mars results from the long-term preferential escape of lighter hydrogen atoms over heavier deuterium atoms. Systematic measurement of the D/H ratio in the Martian upper atmosphere is one of the main goals of the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN).

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 73%

Section: Period 2: September 2018mentioning

confidence: 73%

Section: Figurementioning

confidence: 99%

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Estimate of the D/H Ratio in the Martian Upper Atmosphere from the Low Spectral Resolution Mode of MAVEN/IUVS

et al. 2021

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“…It was suggested that, hydrogen escape was the main channel of atmospheric loss and dehydration of Mars in the past (McElroy, 1972; Parkinson & Hunten, 1972). There is plentiful observational evidence that the amount of hydrogen atoms near the exobase varies with seasons by an order of magnitude with the maximum near perihelion (solar longitude L s ≈ 270°; Bhattacharyya et al., 2017; Chaufray et al., 2021; Halekas, 2017). Seasonal variations have been found for water in the lower atmosphere (Fedorova et al., 2021; Maltagliati et al., 2011, 2013; Smith, 2002; Smith et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

Martian Dust Storms and Gravity Waves: Disentangling Water Transport to the Upper Atmosphere

et al. 2022

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Simulations with the Max Planck Institute Martian general circulation model for Martian years 28 and 34 reveal details of the water “pump” mechanism and the role of gravity wave (GW) forcing. Water is advected to the upper atmosphere mainly by upward branches of the meridional circulation: in low latitudes during equinoxes and over the south pole during solstices. Molecular diffusion plays little role in water transport in the middle atmosphere and across the mesopause. GWs modulate the circulation and temperature during global dust storms, thus changing the timing and intensity of the transport. At equinoxes, they facilitate water accumulation in the polar warming regions in the middle atmosphere followed by stronger upwelling over the equator. As equinoctial storms decay, GWs tend to accelerate the reduction of water in the thermosphere. GWs delay the onset of the transport during solstitial storms and change the globally averaged amount of water in the upper atmosphere by 10%–25%.

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Airglow and Aurora in the Martian Atmosphere: Contributions by the Mars Express and ExoMars TGO Missions

González-Galindo,

Gérard,

Soret

et al. 2024

Space Sci Rev

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The study of atmospheric emissions from orbit to probe the middle and upper atmosphere of Mars, which started with the Mariner missions, is living a golden era thanks to the European Space Agency (ESA) Mars Express mission and other subsequent missions built upon its success, including the ESA ExoMars Trace Gas Orbiter (TGO) mission. Here we summarize the most relevant information obtained by the analysis of atmospheric emissions data from Mars Express and TGO, about the temperature and density structure, the atmospheric dynamics, the chemistry and the atmospheric escape to space. Mars Express also opened a new field of research on Mars with the discovery of aurorae on the planet. We present here the most outstanding results collected by Mars Express about aurorae. Finally, we also discuss how later measurements by other missions have complemented Mars Express and TGO results, and the potential future developments relevant to this field of research.

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Study of the hydrogen escape rate at Mars during martian years 28 and 29 from comparisons between SPICAM/Mars express observations and GCM-LMD simulations

Cited by 29 publications

References 57 publications

Estimate of the D/H Ratio in the Martian Upper Atmosphere from the Low Spectral Resolution Mode of MAVEN/IUVS

Estimate of the D/H Ratio in the Martian Upper Atmosphere from the Low Spectral Resolution Mode of MAVEN/IUVS

Martian Dust Storms and Gravity Waves: Disentangling Water Transport to the Upper Atmosphere

Airglow and Aurora in the Martian Atmosphere: Contributions by the Mars Express and ExoMars TGO Missions

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