Summer Surface Temperatures of the North Polar Region of Mars as Measured by THEMIS

The absence of well defined diurnal cycles, the condensation of the Martian atmosphere in the form of CO2 ice deposits, and the presence of a shallow subsurface water ice table which has a noticeable effect on the apparent thermal inertia as a function of time, have prevented most thermal inertia mappers to cover the polar regions. Here, we propose an alternative approach to the question of the thermophysical properties of the North polar region of Mars by generating a 100 m per pixel mosaic of the surface temperature measured by the Thermal Emission Imaging System (THEMIS) onboard the 2001 NASA Mars Odyssey spacecraft. This mosaic covers latitudes between 65N and 87N, using data collected near ~Ls 100, when the temperatures and the thermal contrast between the different surface units are the largest. This surface temperature map contains significant thermophysical information. Exposed water ice is thermally identified and correlates very well with spectral data from CRISM (when available). In addition to the main body of the perennial cap, water ice is mapped in the form of small patches as far South as 66N. Perennial water ice is identified in several small craters, and in shadowed areas. Finally, the high temperature of the polar erg and intracrater fines illustrate the influence of the albedo and soil grain size on summer surface temperatures.