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Titan's surface from Cassini RADAR SAR and high resolution radiometry data of the first five flybys |
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| Authors: | F Paganelli MA Janssen R West JI Lunine SD Wall RM Lopes RL Kirk L Roth the Radar Team |
| Institution: | a Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA b Space Department, Planetary Exploration Group, Johns Hopkins University Applied Physics Lab, 11100 Johns Hopkins Road, Laurel, MD 20723-6099, USA c Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA d IFSI, INAF, Rome 00133, Italy e Proxemy Research, Bowie, MD 20715, USA f US Geological Survey, Flagstaff, AZ 86001, USA |
| Abstract: | The first five Titan flybys with Cassini's Synthetic Aperture RADAR (SAR) and radiometer are examined with emphasis on the calibration and interpretation of the high-resolution radiometry data acquired during the SAR mode (SAR-radiometry). Maps of the 2-cm wavelength brightness temperature are obtained coincident with the SAR swath imaging, with spatial resolution approaching 6 km. A preliminary calibration shows that brightness temperature in these maps varies from 64 to 89 K. Surface features and physical properties derived from the SAR-radiometry maps and SAR imaging are strongly correlated; in general, we find that surface features with high radar reflectivity are associated with radiometrically cold regions, while surface features with low radar reflectivity correlate with radiometrically warm regions. We examined scatterplots of the normalized radar cross-section σ0 versus brightness temperature, finding differing signatures that characterize various terrains and surface features. Implications for the physical and compositional properties of these features are discussed. The results indicate that volume scattering is important in many areas of Titan's surface, particularly Xanadu, while other areas exhibit complex brightness temperature variations consistent with variable slopes or surface material and compositional properties. |
| Keywords: | Titan Radar observations Satellites surfaces Saturn satellites |
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