HR: 14:25h
AN: U23A-04 INVITED     [Abstracts]
TI: The Character of the Surface of Titan as viewed from the Cassini Orbiter and the Huygens Probe
AU: * Soderblom, L A
EM: lsoderblom@usgs.gov
AF: United States Geological Survey, 2255 N Gemini Drive, Flagstaff, AZ 86004 United States
AB: Images of the surface of Titan continue to be acquired by three instruments aboard the NASA Cassini Orbiter (ISS or Imaging Science Subsystem, the Cassini RADAR, and VIMS or Visible and Infrared Mapping Spectrometer) and were acquired by one instrument (DISR or Descent Imager/Spectral Radiometer) aboard the ESA Huygens Probe during its descent to the surface in January 2005. ISS can image the surface globally and temporally down to about 1 km resolution. RADAR, unhampered by the atmosphere, acquires synthetic aperture images down to about 300 m but will cover only about 0.2 of the surface during the nominal mission. VIMS acquires spectral images the surface to about 1 km resolution through several atmospheric windows but with limited coverage at the highest resolution. The ISS, RADAR, and VIMS images reveal a surface rich in geological diversity. The images show ample evidence for volcanic, fluvial, lacustrine, eolian, and tectonic processes. DISR results reveal that the near-surface methane relative humidity is about 0.5, making methane fog or rain at the landing site unlikely at present. Below about 8 km the eastward zonal wind dropped to <1m/s and reversed back to the west indicative of a boundary layer. Visible and near-infrared surface reflectance is consistent with dirty water ice. DISR images show brighter, higher terrains with stubby and higher-order drainage systems that border darker, lower-lying plains scoured by flow. Surface images show rounded gravels in a dry river bed. DISR-derived topography for the drainages in the bright terrain show extremely rugged terrain with slopes as high as 30 degrees. This suggests relatively rapid erosion by flows in the river beds resulting in the deeply incised valleys.
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
DE: 5422 Ices
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
SC: Union [U]
MN: Fall Meeting 2005