HR: 0800h
AN: P41A-0188    [Abstracts]
TI: Using Combined THEMIS Visible and Infrared Images to map Martian Topography and Slope- corrected Surface Thermal Properties
AU: * Cushing, G E
EM: gcushing@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001, United States
AU: Titus, T N
EM: ttitus@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001, United States
AU: Soderblom, L A
EM: lsoderblom@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001, United States
AU: Kirk, R L
EM: rkirk@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001, United States
AB: Kirk et al. (2005) empirically deconvolved visible and thermal-infrared THEMIS data, isolating topographic information that produced an accurate digital-terrain model (DTM). Described here is the next step wherein we use the same dataset (Columbia Hills area, Mars) in conjunction with the KRC thermal model (Kieffer et al., 1977) to quantitatively derive and map slope-corrected thermophysical properties. Observed surface temperatures, at high spatial resolution, are a function of many variables such as: slope, albedo, thermal inertia, time, season and atmospheric opacity. We constrain each of these variables to construct a DTM and maps of slope-corrected albedo, slope/albedo-corrected thermal inertia, and surface temperatures across an entire scene for any time of day or year and any atmospheric opacity. DTMs greatly facilitate analyses of the Martian surface, but generating these data is a challenge. The MOLA global dataset does not have sufficient resolution (~3 km) to be combined with newer datasets (e.g. HiRISE, CTX, THEMIS, MOC, and CRISM), so new techniques to derive high-resolution DTMs are always being explored. Stereo imaging produces quality, high-resolution DTMs but is limited in the amount of available coverage. Photoclinometry techniques on visible-wavelength images have been widely investigated with varying degrees of success, but accounting for albedo variations across a scene has been an historical weakness of this method. Here we discuss a technique of combining THEMIS visible and thermal infrared (both daytime and nighttime) observations (Christensen et al., 2004) in such a manner that albedo variations in the scene are cancelled, allowing the production of a high-resolution DTM via photoclinometry techniques that are largely free of albedo-induced errors. We employ the KRC thermal-diffusion model to generate models of slope-corrected thermal properties from the resultant DTM and THEMIS observations. This technique can provide new perspectives and insights into studies of surface thermodynamics, and provide engineering constraints to future missions. References: Christensen, P.R. et al., Space Science Reviews, 110, 85-130, 2004; Kieffer, H.H. et al., Journal of Geophysical Research, 82(28), 4249- 4291, 1977; Kirk, R.L. et al., Photogrammetric Engineering & Remote Sensing, v 71, n 10, p 1167-1178, October 2005.
DE: 0540 Image processing
DE: 3225 Numerical approximations and analysis (4260)
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting