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Free convection in the Martian atmosphereResearchers investigated the free convective regime for the Martian atmospheric boundary layer (ABL). Researchers generalized Schumann's model describing horizontal fluctuations and mean vertical gradients occurring during free convection to include convection driven by water vapor gradients and to include the effects of circulation above both aerodynamically smooth and rough surfaces. Applying the model to Mars, researchers found that nearly all the resistance to sensible and latent heat transfer in the ABL occurs within the thin interfacial sublayer at the surface. Free convection is found to readily occur at low pressures and high temperatures when surface ice is present. At 7 mb, the ABL should freely convect whenever the mean windspeed at the top of the surface layer drops below about 2.5 m s(-1) and surface temperatures exceed 250 K. Mean horizontal fluctuations within the surface layer are found to be as high as 3 m (-1) for windspeed, 0.5 K for temperature, and 10 (-4) kg m (-3) for water vapor density. Airflow over surfaces similar to the Antarctic Polar Plateau was found to be aerodynamically smooth on Mars during free convection for all pressures between 6 and 1000 mb, while surfaces with z sub o approx. equals 1 cm are aerodynamically rough over this pressure range.
Document ID
19920001585
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Clow, G. D. (Geological Survey Menlo Park, CA., United States)
Haberle, R. M. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1991
Publication Information
Publication: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1990
Subject Category
Lunar And Planetary Exploration
Accession Number
92N10803
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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