HR: 1340h
AN: P23B-1351    [Abstracts]
TI: Titan Topography: A Comparison Between Cassini Altimeter and SAR Imaging from Two Titan Flybys
AU: * Gim, Y
EM: ygim@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Stiles, B
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Callahan, P S
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Johnson, W T
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Hensley, S
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Hamilton, G
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: West, R
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AU: Alberti, G
AF: CORISTA, Viale Kennedy 5, Naples, 80125, Italy
AU: Flamini, E
AF: Agenzia Spaziale Italiana, Viale Liegi 26, Rome, 00198, Italy
AU: Lorenz, R D
AF: Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, United States
AU: Zebker, H A
AF: Stanford University, Dept. of Geophysics and Electrical Engineering, Stanford, CA 94305, United States
AU: Cassini RADAR team, T
AB: The Cassini RADAR has collected twelve altimeter data sets of Titan since the beginning of the Saturn Tour in 2004. Most of the altimeter measurements were made at high altitudes, from 4,000 km to 15,000 km, resulting in low spatial resolutions due to beam footprint sizes larger than 20 km, as well as short ground tracks less than 600 km. One flyby (T30) was dedicated to altimeter data collection from 15,000 km to the closest approach altitude of 950 km. This produced a beam footprint size of 6 km at the lowest altitude and an altimeter ground track of about 3,500 km covering Titan's surface from near the equator to high latitude areas near Titan's north pole. More importantly, the ground track is located inside the SAR swath viewed from an earlier Titan flyby (T28). This provides a rare opportunity to investigate Titan topography with a relatively high spatial resolution and compare nadir-looking altimeter data with side-looking SAR imaging. From altimeter data, we have measured the mean Titan radius of 2575.1 km +/- 0.1 km and observed rather complex topographical variations over a short distance. By comparing altimeter data and SAR images at altitudes below 2,000 km, we have found that there is a strong correlation between SAR brightness and altimeter waveform; SAR dark areas correspond to strong and sharp altimeter waveforms while SAR bright areas correspond to weak and diffused altimeter waveforms. The research described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
DE: 6281 Titan
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting