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H2O frost point detection on MarsThe Viking Mars landers contain meteorological instrumentation to measure wind, temperature, and pressure but not atmospheric water content. The landings occurred during local summer, and it was observed that the nocturnal temperature decrease at sensor height (1.6 m) did not exhibit a uniform behavior at either site. It was expected that the rate of decrease would gradually slow, leveling off near sunrise. Instead, a leveling occurred several hours earlier. Temperature subsequently began a more rapid decrease which slowed by sunrise. This suggested that the temperature sensors may be detecting the frost point of water vapor. Analysis of alternative hypotheses demonstrates that none of these are viable candidates. The frost point interpretation is consistent with other lander and orbiter observations, with terrestrial experience, and with modeling of Mars' atmospheric behavior. It thus appears that the meteorology experiment can help provide a basis toward understanding the distribution and dynamics of Martian water vapor.
Document ID
19810039086
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Ryan, J. A.
(California State Univ. Fullerton, CA, United States)
Sharman, R. D.
(California State University Fullerton, Calif., United States)
Date Acquired
August 11, 2013
Publication Date
January 20, 1981
Publication Information
Publication: Journal of Geophysical Research
Volume: 86
Subject Category
Lunar And Planetary Exploration
Accession Number
81A23490
Funding Number(s)
CONTRACT_GRANT: NAS1-14621
CONTRACT_GRANT: NSG-7614
Distribution Limits
Public
Copyright
Other

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