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Surface thermal inertia derived from satellite imagery offers a valuable tool for remotely mapping the physical structure and water content of planetary regolith. Efforts to quantify thermal inertia using surface temperatures on Earth, however, have consistently yielded large uncertainties and suffered from a lack of reproducibility. Unlike dry or airless bodies, Earth's abundant water and dense atmosphere lead to dynamic thermophysical conditions that are a greater challenge to model than on a world like Mars. In this work, an approach was developed using field experiments to inform and fine‐tune a thermophysical model of terrestrial sediment and calculate an inherent thermal inertia value with higher precision and less initial knowledge of the sediment than has previously been achieved remotely on Earth. A thermal inertia derived for a basaltic tephra site in Northern Arizona was replicated within 1% between different field seasons, demonstrating reproducibility. Model‐derived values were validated in situ by two different thermophysical field probes to within 8% of the measured mean values. Analog studies such as this hold the promise of improved interpretations of surface materials on Mars, and an accurate thermal model for Earth is the key step to enabling translation between the two worlds. Key Points: This work introduces a new approach for relating remote temperature observations to regolith physical propertiesThe manuscript details the development, calibration, and testing of a soil‐agnostic thermophysical model for application to Earth and MarsSoil moisture and temperature have dynamic effects on thermal conductivity and latent heat that depend on regolith type [ABSTRACT FROM AUTHOR]

The light-toned sedimentary layers that outcrop widely throughout Mars' Southern Highlands have long been an enigma in uncovering the climatic history of Mars. Although these units seem to contain unique records of fluctuating surface conditions, the role of water in their formation is debated. A distinctive property of many such deposits is their elevated thermal inertia relative to that of surrounding materials. This temperature-controlling trait is often interpreted to indicate induration resulting from aqueous processes. However, prevalent erosional landforms suggest that the deposits host much weaker materials than neighboring units. We address this apparent contradiction by disentangling the relationships between thermal inertia, mineralogy, and erosion susceptibility and by quantifying the cohesion of layered deposits in the Arabia Terra region. We demonstrate that variations in dust cover associated with relative erodibility and eolian abrasion can be inconspicuous controls on apparent thermal inertia. We ultimately find that these deposits are not as cohesive as would be expected from a high water-to-rock ratio setting either during or after deposition. If waterrich surface conditions existed in the region after the Noachian, these deposits suggest they may have only been intermittent and fleeting. [ABSTRACT FROM AUTHOR]

Model-derived thermal inertias (TIs) have frequently been used to help distinguish geologic units in mapping efforts of the surface of Mars. Generally, higher TI values are associated with compacted surfaces and bedrock, while lower values are associated with poorly consolidated sediments and other friable deposits [1]. Our efforts to map layered sedimentary deposits within equatorial craters on Mars have revealed an inconsistent correlation between TI and geologic unit type [2]. Over areas where surface landform morphologies and VNIR spectra remain relatively constant, modeled TI sometimes varies dramatically. One possible explanation for the patterns in TI is that thin dust coatings have a strong influence on surface temperatures, and that dust accumulation is limited in very friable units and regions of high wind velocities by aeolian erosion [3]. If this is the case, it will force us to reassess how we use TI maps in geologic mapping. We tested the localized dust cover hypothesis by taking a statistical approach to uncovering nuanced relationships between mineral signals, crater densities, wind patterns and TI. We found that surface TI is frequently reduced on heavily cratered terrains and leeward slopes compared to crater-free surfaces containing erosional landforms (e.g. yardangs) and windward slopes. As a result, we suggest that geologic mapping efforts on Mars must consider local erosional patterns and abrasion susceptibility when using thermal inertia as a tool for differentiating geologic units. [ABSTRACT FROM AUTHOR]

Model-derived thermal inertias (TIs) have frequently been used to help distinguish geologic units in mapping efforts of the surface of Mars. Generally, higher TI values are associated with compacted surfaces and bedrock, while lower values are associated with poorly consolidated sediments and other friable deposits [1]. Our efforts to map layered sedimentary deposits within equatorial craters on Mars have revealed an inconsistent correlation between TI and geologic unit type [2]. Over areas where surface landform morphologies and VNIR spectra remain relatively constant, modeled TI sometimes varies dramatically. One possible explanation for the patterns in TI is that thin dust coatings have a strong influence on surface temperatures, and that dust accumulation is limited in very friable units and regions of high wind velocities by aeolian erosion [3]. If this is the case, it will force us to reassess how we use TI maps in geologic mapping. We tested the localized dust cover hypothesis by taking a statistical approach to uncovering nuanced relationships between mineral signals, crater densities, wind patterns and TI. We found that surface TI is frequently reduced on heavily cratered terrains and leeward slopes compared to crater-free surfaces containing erosional landforms (e.g. yardangs) and windward slopes. As a result, we suggest that geologic mapping efforts on Mars must consider local erosional patterns and abrasion susceptibility when using thermal inertia as a tool for differentiating geologic units. [ABSTRACT FROM AUTHOR]