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Reanalysis of Clementine Bistatic Radar Data from the Lunar South PoleOn 9 April 1994 the Clementine spacecraft high-gain antenna was aimed toward the Moon's surface and the resulting 13-cm wavelength radio echoes were received on Earth. Using these data, we have found that the lunar surface generally follows a Lambertian bistatic scattering function sigma(sub 0) = K(sub D)cos(theta(sub i) with K(sub D) approx. 0.003 for the opposite (expected) sense of circular polarization and K(sub D) approx. 0.001 for the same (unexpected) sense. But there are important deviations-of up to 50% in some parts of the echo spectrum-from this simple form. Based on an earlier analysis of these same data, Nozette et al. claimed detection of an enhancement in echoes with right circular polarization from regions near the South Pole in a near-backscatter geometry. Such behavior would be consistent with presence of perhaps large quantities of water ice near the Pole. We have been unable to reproduce that result. Although we find weak suggestions of enhanced echoes at the time of South Pole backscatter, similar features are present at earlier and later times, adjacent frequencies, and in left circular polarization. If enhanced backscatter is present, it is not unique to the South Pole; if not unique to the Pole, then ice is less likely as an explanation for the enhancement.
Document ID
19990047963
Acquisition Source
Headquarters
Document Type
Preprint (Draft being sent to journal)
Authors
Simpson, Richard A. (Stanford Univ. Stanford, CA United States)
Tyler, G. Leonard (Stanford Univ. Stanford, CA United States)
Date Acquired
September 6, 2013
Publication Date
March 12, 1998
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAGw-4878
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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