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Water Vapor Variability in the Thermosphere of Mars During Mars Years 32–36
Journal article   Open access   Peer reviewed

Water Vapor Variability in the Thermosphere of Mars During Mars Years 32–36

Zachary R Girazian
Journal of geophysical research. Planets, Vol.129(2), e2023JE008117
02/2024
DOI: 10.1029/2023JE008117
url
https://doi.org/10.1029/2023JE008117View
Published (Version of record) Open Access

Abstract

Using Mars Atmosphere and Volatile Evolution observations, we characterize the variability of water vapor in the Martian thermosphere during Mars Years 32–36. Near a fixed atmospheric pressure level of ∼5 × 10−7 Pa, the typical water density is 1.7 (±1.0) × 103 cm−3 and the typical water mixing ratio is 14.6 (±9.0) ppm. Thermospheric water levels are higher during the southern spring and summer seasons when Mars is near perihelion and there is significant dust loading in the lower atmosphere. However, the seasonal variation is not the same from year-to-year, likely due to annual differences in dust loading. Water vapor abundance is highly correlated with the amount of dust in the lower atmosphere, and increases during both regional and global dust storms. Additionally, there is a local time asymmetry with higher mixing ratios observed during morning local times, potentially caused by atmospheric circulation. Our results support previous work that found increased dust levels allow more water to be supplied directly to the thermosphere.
Ionosphere Mars water thermosphere dust MAVEN UIOWA OA Agreement

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