We describe preliminary results from the first 100 sols of ground temperature measurements along the Mars Science Laboratory's traverse from Bradbury Landing to Rocknest in Gale. The ground temperature data show long-term increases in mean temperature that are consistent with seasonal evolution. Deviations from expected temperature trends within the diurnal cycle are observed and may be attributed to rover and environmental effects. Fits to measured diurnal temperature amplitudes using a thermal model suggest that the observed surfaces have thermal inertias in the range of 265-375?J m-2 K-1 s-1/2, which are within the range of values determined from orbital measurements and are consistent with the inertias predicted from the observed particle sizes on the uppermost surface near the rover. Ground temperatures at Gale Crater appear to warm earlier and cool later than predicted by the model, suggesting that there are multiple unaccounted for physical conditions or processes in our models. Where the Mars Science Laboratory (MSL) descent engines removed a mobile layer of dust and fine sediments from over rockier material, the diurnal temperature profile is closer to that expected for a homogeneous surface, suggesting that the mobile materials on the uppermost surface may be partially responsible for the mismatch between observed temperatures and those predicted for materials having a single thermal inertia. Models of local stratigraphy also implicate thermophysical heterogeneity at the uppermost surface as a potential contributor to the observed diurnal temperature cycle. Key Points Diurnal ground temperatures vary with location Diurnal temperature curves are not well matched by a homogeneous thermal model GTS data are consistent with a varied stratigraphy and thermophysical properties.
V.E.H. is supported by the Mars Science Laboratory and 2001 Mars Odyssey Participating Scientist Programs. E.S., C.A., M.R., I.C., J.G.‐E., M.A.D.P., J.M.‐T., and M.‐P.Z. are supported by the Economy and Competitivity Ministry (projects AYA2011‐25720 and AYA2012‐38707). A.V., M.T.L., and M.T.J. are supported by the Mars Science Laboratory project. W.G. acknowledges partial funding by the Deutsche Forschungsgemeinschaft (DFG grant GO 2288/1‐1). M.B.M. is supported by the Danish Council for Independent Research/Natural Sciences (FNU grant 0602‐02713B). We greatly appreciate all of the scientists and engineers who spent many years working to make the MSL mission such a success. We also thank the MSL Science Team for their support of the REMS investigation, and we deeply appreciate the REMS PULs and PDLs (who do the daily hard work of planning and validating REMS data, usually in the middle of the Spanish night). We are grateful to Tim Parker and Fred Calef at JPL for rapid updates to and information about the rover localization data. Others who have contributed their time and/or advice include Elena McCartney (MSSS), Larry Edwards (NASA Ames), the MSLICE team at JPL, Josh Bandfield (SSI), Hugh Kieffer (Celestial Reasonings), Than Putzig (SwRI), Bob Haberle (NASA Ames), F. Scott Anderson (SwRI), Chris Edwards (Caltech), Mike Smith (GSFC), Mike Wolff (SSI), Jonathan Hill (ASU), Kelly Bender (ASU), Dale Noss (ASU), and Kimm Murray (ASU). Last, but definitely not the least, we thank Josh Bandfield and an anonymous reviewer for thorough, constructive critiques that helped improve the manuscript.
- ground temperature
- thermal inertia