Thermophysical observations and applications to geologic processes on Mars

Techniques were developed to calculate thermal inertia values from high-resolution orbital data and surface measurements and to better understand the geologic and climatic history of localities on Mars. Thermal inertia values were derived from Mars Odyssey Thermal Emission Spectrometer (THEMIS) nighttime temperature data and provide the highest resolution thermal inertia dataset to date (100 m per pixel). The accuracy of the thermal inertia estimations are ∼20%, and errors are primarily due to the instrument calibration and small-scale variations in albedo. The precision is 10-15%, thus thermal inertia differences in individual THEMIS images represent accurate changes in the physical properties of the surface. Dust-mantled surfaces, bedform material, interior layered deposits, and exposed bedrock were studied to illustrate the improved understanding of surfaces provided by THEMIS thermal inertia data.; Multiple datasets were integrated to construct a unit map of eastern Arabia Terra based on the thermophysical and morphologic features of the surface, and was used to determine the relative age of these surface materials and interpret the geologic history of this area. Volcanic, fluvial, and aeolian processes have modified this region, and suggest that this area has undergone multiple environmental and climactic changes. Dust may not be currently accumulating in the low thermal inertia regions, but likely remains a relatively constant thickness over time.; Thermal inertia values were derived from the Miniature Thermal Emission Spectrometer (Mini-TES) diurnal temperature measurements at both Mars Exploration Rover (MER) landing sites, and provide the first opportunity to compare thermal inertia values and morphologic and textural characteristics of the same material and verify orbital data. Particle sizes derived from thermal inertia correspond to directly measured particle sizes using Microscopic Imager (MI) images in material filling hollows, the Gusev soil, and bedforms. Results suggest that techniques derived from laboratory measurements provide a reasonable derivation of particle sizes from thermal inertia values. Mini-TES-derived thermal inertia values at Gusev along a ∼2.5 km traverse follow trends in thermal inertia measured from orbit with TES and THEMIS. However, there is variability along the traverse that is not resolved in the orbital data due to meterscale processes that are not identifiable at larger scales.