Surface energy budget and thermal inertia at Gale Crater: Calculations from ground‐based measurements

Abstract

The analysis of the surface energy budget (SEB) yields insights into soil-atmosphere interactions and local climates, while the analysis of the thermal inertia (I) of shallow subsurfaces provides context for evaluating geological features. Mars orbital data have been used to determine thermal inertias at horizontal scales of ∼104 m2 to ∼107 m2. Here we use measurements of ground temperature and atmospheric variables by Curiosity to calculate thermal inertias at Gale Crater at horizontal scales of ∼102 m2. We analyze three sols representing distinct environmental conditions and soil properties, sol 82 at Rocknest (RCK), sol 112 at Point Lake (PL), and sol 139 at Yellowknife Bay (YKB). Our results indicate that the largest thermal inertia I = 452 J m−2 K−1 s−1/2 (SI units used throughout this article) is found at YKB followed by PL with I = 306 and RCK with I = 295. These values are consistent with the expected thermal inertias for the types of terrain imaged by Mastcam and with previous satellite estimations at Gale Crater. We also calculate the SEB using data from measurements by Curiosity's Rover Environmental Monitoring Station and dust opacity values derived from measurements by Mastcam. The knowledge of the SEB and thermal inertia has the potential to enhance our understanding of the climate, the geology, and the habitability of Mars.

Mars Science Laboratory diurnal moisture observations and column simulations

“…During MSL sols 15–17 ( L s ~159°) the Curiosity rover was at the Bradbury landing site, with the roughness lengths for momentum and heat ( z 0m , z 0h ) of 0.01 m, LW emissivity of 0.96, and well‐mixed dust with optical depth τ vis of 0.6 assumed in the model. Thermal inertia of 300 tiu and albedo of 0.15 provided good simulations of T 1.6 m (Figure ); these local values are lower than the large‐scale estimates from orbiters but are consistent with the estimates of Hamilton et al [] and Martínez et al []. The diurnal variation of the surface pressure (mostly due to the large‐scale thermal tide [ Read and Lewis , ]) is not provided by the local 1‐D model so a Fourier series fit to the hourly observations of p s (690–780 Pa [ Harri et al ., ]) is used.…”

“…The surface is about 25 K warmer than T 1.6 m during the midday hours (a strongly superadiabatic stratification) and 3–5 K cooler during the night (stable stratification). The REMS‐H 1.6 m temperatures are fairly similar to those reported for sols 15–17 from REMS‐T in Martínez et al [], the surface temperatures from REMS‐GTS [ Hamilton et al ., ; Martínez et al ., ] indicating morning minima and daytime maxima slightly lower than those from the model.…”

Análisis de las condiciones ambientales en el cráter Gale a partir de mediciones REMS/MSL

“…We have also estimated the daily UV irradiation using dust opacity values derived from the Mastcam instrument. For more specific information on scientific results obtained from the different REMS sensors, the reader is referred to Harri et al (2014a), Haberle et al (2014), Kahanpää et al (2016) and Guzewich et al (2016) for the PS; Hamilton et al (2014), Martínez et al (2014) and Martínez et al (2015) for the GTS; Harri et al (2014b), Martín-Torres et al (2015), Savijärvi et al (2015a), Martínez et al (2015) and Savijärvi et al (2015b) for the RHS and Smith et al (2016) for the UVS. REMS has already provided the most comprehensive coverage of near-surface environmental conditions recorded by a spacecraft landed on Mars.…”

Improving Slip Prediction on Mars Using Thermal Inertia Measurements

“…Unfortunately, the resolution of orbital thermal imaging sensors is too low to detect many rover-scale hazards. The Miniature Thermal Emission Spectrometer (Mini-TES) instruments aboard the Mars Exploration Rovers and the GTS on Curiosity have been used to analyze surface physical properties but were not designed for traversability prediction and are not used in daily path planning [23,17,34]. This paper presents a quantitative analysis of whether considering thermal inertia improves slip prediction on Mars using data from Curiosity's GTS [49] and the Mars Reconnaissance Orbiter's THEMIS [11].…”