HR: 16:00h
AN: P24A-01    [Abstracts]
TI: Searching for Change in the Martian Night: Investigating Nighttime Temperature Anomalies Using THEMIS
AU: * Christensen, P R
EM: phil.christensen@asu.edu
AF: Arizona State University, Dept. of Geological Sciences, Tempe, AZ 85287-6305 United States
AU: Gorelick, N
EM: gorelick@asu.edu
AF: Arizona State University, Dept. of Geological Sciences, Tempe, AZ 85287-6305 United States
AU: Fergason, R
EM: robin.fergason@asu.edu
AF: Arizona State University, Dept. of Geological Sciences, Tempe, AZ 85287-6305 United States
AB: An important objective of the THEMIS infrared camera on Mars Odyssey is the search for temperature anomalies associated with near-surface volcanic heating, near-surface water or ice, or dynamic surface changes. THEMIS has mapped virtually all of Mars at night in the infrared at 100-m per pixel resolution, and has observed portions of the surface a second time 1-2 years later. Investigations have been conducted of all of these images to search for maximum temperatures greater than those expected from rocks or bedrock alone (>220K), and no example has been found in any image of temperatures that require an internal heat source. We have also searched for spatial patterns potentially associated with recent volcanic activity, hydrothermal heat, or evaporative cooling associated with near-surface water in the youngest terrains, but the very high spatial variability associated with surface properties greatly complicates any interpretation. To overcome this surface complexity, we have initiated a search for changes in surface temperature in an effort to isolate changes due to dynamic heating or cooling processes. This process involves the use of histogram adjustments of the overlapping portions of two images to remove the complicating factors that the Odyssey orbit varies by 2 hours in local time and the differences in season between the different observations. In addition, we have converted many images to thermal inertia using the THEMIS Standard Thermal Model developed by H. Kieffer and R. Fergason. To date no significant changes have been detected - but the search continues.
DE: 5418 Heat flow
DE: 5419 Hydrology and fluvial processes
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005