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Mars: Wavelength-dependent dual polarization global scatteringDuring the 1988 and 1990 Mars oppositions, the first continuous-wave (CW) multi-wavelength radar observations were performed that include the entire echo in both polarizations. These observations, coordinated in subradar coverage when possible, were made with the Arecibo S-band (12.6 cm lambda) and Goldstone X-band (3.5 cm lambda) facilities. The CW spectra obtained during these oppositions have been studied using a variety of techniques to explore the spatial and wavelength dependence of both the Same-sense Circular (SC) and Opposite-sense Circular (OC) polarization returns. Earlier multi-wavelength comparisons dealt primarily with the quasispecular component of the echoes. Our work in contrast has much new information (at high signal-to-noise) for the SC 'depolarized component. The unique value of these radar observations lies in their potential for probing the subsurface scattering behavior in 'appropriate' terrain. The clearest case for wavelength dependence in the SC component is the scattering behavior over Tharsis, where the X-band features are significantly weaker than the S-band features. This hypothesis was advanced to account for the low thermal inertia of Tharsis, but also can explain the S/X differences if the layer is about 40 cm thick. In contrast to the Tharsis result, the depolarized echo from the heavily cratered terrain is actually stronger at X-band. The obvious interpretation is that more scatterers exist at the scale of the shorter wavelength, either at the surface or as a distributed subsurface scatterers. The strongest depolarized feature of the X-band spectra is associated with the south residual polar cap. The radar cross section of this feature corresponds to an equivalent full-disk albedo of unity.
Document ID
19920019777
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Harmon, J. K.
(Northeast Artificial Intelligence Consortium Arecibo, Puerto Rico)
Slade, M. A.
(Northeast Artificial Intelligence Consortium Arecibo, Puerto Rico)
Hudson, R. S.
(Northeast Artificial Intelligence Consortium Arecibo, Puerto Rico)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Lunar and Planetary Inst., Workshop on the Martian Surface and Atmosphere Through Time
Subject Category
Lunar And Planetary Exploration
Accession Number
92N29020
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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