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Modeling Radar Scatter from Icy and Young Rough Lunar CratersFor lunar orbital synthetic aperture radars, such as the Chandrayaan Mini-RF operating at S- band (13-cm) wavelength and the Lunar Reconnaissance Orbiter Mini-RF operating at S- band and X-band (3-cm) wavelengths, it is important to understand the radar backscattering characteristics of the icy and young, rough craters. Assuming a mixing model consisting of diffuse and quasi-specular scattering components, we have modeled the opposite-sense circular (OC) and same-sense circular (SC) backscattering characteristics. The specular component, consisting of only OC echoes, represents the echoes from the surface and subsurface layers that are oriented perpendicular to the radar's line-of-sight. The diffuse component, consisting of both SC and OC echoes, represents the echoes associated with either rocks or ice. Also, diffuse echoes have backscatter that is proportional to the cosine of the incidence angle. We modeled how these two (specular and diffuse) radar scattering components could be modulated by factors such as surface roughness associated with young craters. We also modeled how ice radar scattering components could be modulated by a thin regolith covering, and/or by the situation where ice occupies small patches within a larger radar pixel. We tested this modeling by examining 4 nonpolar craters and 12 polar craters using LRO Mini-RF data. Results indicate that icy and young rough craters can be distinguished based upon their SC enhancements (Alpha) and OC enhancements (Gamma). In addition, we also examined the craters that have unusual circular polarization ratios (CPRs) that likely result from a double bounce mode of scattering. Blocky fresh craters, icy craters, and craters exhibiting double bounce scattering can be separated based on the values of Alpha, Gamma, the ratio of Alpha/Gamma and the weighted sum of Alpha and Gamma.
Document ID
20140002111
Acquisition Source
Jet Propulsion Laboratory
Document Type
Presentation
External Source(s)
Authors
Thompson, Thomas (Tommy)
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Ustinov, Eugene
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Spudis, Paul
(Lunar and Planetary Inst. Houston, TX, United States)
Fessler, Brian
(Lunar and Planetary Inst. Houston, TX, United States)
Date Acquired
March 20, 2014
Publication Date
March 20, 2012
Subject Category
Lunar And Planetary Science And Exploration
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: Houston, TX
Country: United States
Start Date: March 19, 2012
End Date: March 23, 2012
Sponsors: Lunar and Planetary Inst.
Distribution Limits
Public
Copyright
Other
Keywords
lunar craters
modeling radar scattering
lunar orbital synthetic aperture radars

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