Widespread Shallow Water Ice on Mars at High Latitudesand Midlatitudes

We derive the depth of the water ice table on Mars by fitting seasonal surface temperature trends acquired by the Mars Climate Sounder and Thermal Emission Imaging System with a two-layer regolith model assuming frozen H₂O as the lower material. Our results are consistent with widespread water ice at latitudes as low as 35°N/45°S buried sometimes a few centimeters below sand-like material, with high lateral ice depth variability, and correlated with periglacial features. While several investigations have already predicted, identified, and characterized some properties of near-surface ice on Mars, our results constitute a significant advance in the context of the upcoming crewed exploration because (1) they focus on very shallow depths accessible with limited equipment, (2) they provide continuous regional coverage including the midlatitudes, and (3) they yield moderate spatial resolution maps (3 ppd) relevant to landing site selection studies.