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Water vapor at Jezero Crater, Mars

Presentation #318.04 in the session Mars’s Story as Told and Influenced by Dust and Water (Oral Presentation)

Published onOct 23, 2023
Water vapor at Jezero Crater, Mars

Near-surface atmospheric water on Mars is of interest today to assess the current cycling of water in and out of the regolith, cycling of water on and off of the polar caps, and to understand the current habitability potential of Mars. The regolith at polar and non-polar latitudes is an important reservoir for water storage, and an important resource for human exploration, and exchange of water between the regolith and atmosphere may play an important role in the global water cycle. Understanding water on Mars today helps us model the water cycle during different epochs on Mars, during which there was much more liquid water present in the system and Mars may have been inhabited.

Previously, the Phoenix polar mission and the Curiosity rover mission provided near-surface relative humidity measurements [e.g., 1,2]. The Perseverance MEDA instrument, with its improved calibration, provides additional valuable information regarding these processes. MEDA data are collected typically for an hour, ever other hour, throughout a sol (Martian day), with the even-hours and odd-hours alternating every other sol. The data show the expected diurnal and seasonal signals for water vapor, but additionally, show high-frequency variability and sol-to-sol variability that are not fully understood. Used in conjunction with the Perseverance SuperCam or TIRS instruments, the MEDA measurements of relative humidity can be used to detect frost formation [3], to assess diurnal changes in the near-surface water content, possibly due to subsurface exchange (e.g., [6-7, 1]) or consistent with surface frost [3], and to check whether the environmental conditions at the surface and in the near surface are compatible with the formation of liquid brines [4-5]. In addition, MEDA relative humidity measurements are collected near in time to sample collection to understand the water vapor that may be trapped in the sample container headspace [8].

We examine the first full year of near-surface water vapor in the Martian atmosphere in the vicinity of Jezero Crater, Mars, where the Perseverance Rover is currently operating and acquiring data. We place these water measurements into the broader context, relating measurements to those of orbiters and other landers.

References: [1] Tamppari and Lemmon, 2020, [2] Fischer et al., 2019. [3] Martínez et al., 2016, [4] Martín-Torres et al., 2015, [5] Rivera Valentín et al. 2018, [6] Martínez et al., 2017; [7] Savijärvi et al., 2019b, [8] Zorzano et al., 2023.

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