Details

Autor(en) / Beteiligte

• Vasavada, Ashwin R.
• Piqueux, Sylvain
• Lewis, Kevin W.
• Lemmon, Mark T.
• Smith, Michael D.

Titel

Thermophysical properties along Curiosity's traverse in Gale crater, Mars, derived from the REMS ground temperature sensor

Ist Teil von

• Icarus (New York, N.Y. 1962), 2017-03, Vol.284, p.372-386

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Thermal inertia and albedo are derived from ground temperature measurements along the Curiosity rover's traverse.•Diffuse water ice clouds or hazes can significantly influence ground temperatures in the southern fall and winter.•The shape of the diurnal ground temperature curve is used to isolate the bedrock thermal inertia from other materials within the sensor footprint.•Thermal inertias of sedimentary rock may be significantly higher than apparent in data sets with sparse local time coverage. The REMS instrument onboard the Mars Science Laboratory rover, Curiosity, has measured ground temperature nearly continuously at hourly intervals for two Mars years. Coverage of the entire diurnal cycle at 1Hz is available every few martian days. We compare these measurements with predictions of surface-atmosphere thermal models to derive the apparent thermal inertia and thermally derived albedo along the rover's traverse after accounting for the radiative effects of atmospheric water ice during fall and winter, as is necessary to match the measured seasonal trend. The REMS measurements can distinguish between active sand, other loose materials, mudstone, and sandstone based on their thermophysical properties. However, the apparent thermal inertias of bedrock-dominated surfaces (∼350–550Jm−2K−1s−½) are lower than expected. We use rover imagery and the detailed shape of the diurnal ground temperature curve to explore whether lateral or vertical heterogeneity in the surface materials within the sensor footprint might explain the low inertias. We find that the bedrock component of the surface can have a thermal inertia as high as 650–1700Jm−2K−1s−½ for mudstone sites and ∼700Jm−2K−1s−½ for sandstone sites in models runs that include lateral and vertical mixing. Although the results of our forward modeling approach may be non-unique, they demonstrate the potential to extract information about lateral and vertical variations in thermophysical properties from temporally resolved measurements of ground temperature.