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Spectral properties /0.04 to 0.75 microns/ of soils exposed at the Viking 1 landing siteThe bidirectional reflectance and photometric function (Hapke, 1981) was determined for seven patches of soil located near the Viking Lander 1 spacecraft. The soil photometric function has a prominent opposition effect in addition to a phase function that is strongly backscattering. The ratio of reflectances at a 1 deg phase angle to that at a 10 deg phase angle averages 1.25, 1.24, and 1.19 for blue, green, and red wavelengths respectively. The photometric function has a wavelength dependence, which causes color ratios to vary by up to 33% as a function of phase angle. Estimates of soil reflectance at a 5 deg phase angle averaged over the blue and green passbands of the Viking Lander cameras are 0.11 and 0.17, respectively, while estimates over the red channel range from 0.30 to 0.39. Brightness and color variations within the soil can be correlated with particle size, finer-grained soil being brighter and redder than coarser-grained soil. Lander soils, homogeneous in nature, are typical of brighter soils covering a large portion of the Martian surface.
Document ID
19810062285
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Guinness, E. A.
(Washington University St. Louis, MO, United States)
Date Acquired
August 11, 2013
Publication Date
September 10, 1981
Publication Information
Publication: Journal of Geophysical Research
Volume: 86
Subject Category
Lunar And Planetary Exploration
Accession Number
81A46689
Funding Number(s)
CONTRACT_GRANT: NSG-7545
Distribution Limits
Public
Copyright
Other

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