Linking Thermophysics from Earth to Mars

Abstract:

The thermophysical properties of terrains on Earth have been relegated to qualitative assessments of degree of induration, soil moisture, and particle sizes. The ability to compare thermophysical (e.g. specific heat, thermal conductivity, porosity and density) and thus properties across planetary bodies is key for analog studies that rely on remote and in situ interpretations. This is particularly relevant for Mars, where thermal infrared data have been readily acquired and thermal inertia derived over much of the surface, including highly localized studies to assess soil moisture, environmental conditions, and the presence/depth of buried ice. Leveraging hyper-localized studies using ground-based rover and lander data enable some degree of relation from ground to orbit, though these efforts are often limited to specific terrain types.

Here we present the first results from a field campaign in the San Francisco Volcanic Field in Arizona as a precursor to our more exhaustive field campaign in the Mojave Desert (e.g. sand dunes, playa, alluvial fans, etc.). We deployed our ground station with a >30 sensors to constrain the boundary conditions, including a suite of pole-mounted instruments (FLIR Duo Pro R, 2 directional anemometers, air temperature/humidity/pressure, upwelling/downwelling short/long wavelength radiometer), and ground sensors (surface temperature (12), and soil moisture sensors (12), 2 TIR calibration targets). When used with our Terrestrial Laser Scanner, UAV-based Structure from Motion topography and multispectral VNIR and TIR imaging, we collected comprehensive data over a 40x40 m area and tied our remotely sensed data directly to ground sampled data obtained from our sampling grid. Samples were returned to the lab for thermal effusivity and laser diffraction grain size measurements. After all data are collected, we will model the thermal inertia of the field site and quantitatively tie it to out in situ sampling for independent validation.