Quantifying the connections between topographic characteristics and lunar regolith properties in the permanently shadowed regions

The abundance and distribution of ice on the Moon is still unknown. Landforms on the lunar surface are modified by various surface processes, which are likely influenced by the thermal state of regolith and the presence or absence of ice. However, few studies have studied geomorphic evidence for the presence of lunar ice deposits using detailed, high-quality data of surface topography and characteristics of permanently shadowed regions (PSRs). Here, we examine the connections between geomorphic characteristics and the presence of lunar ice by 1) quantifying the surface characteristics such as roughness based on high-resolution optical images and topography data and 2) modeling the spatial variations of water ice stability using a high-resolution thermal model. We focus our study on the Scott-E crater in the south polar region of the Moon, which has a large size, a symmetric circular form, a strongly asymmetric north-south illumination and thermal environment, available high-quality LROC NAC scattered light imageries, and anticipated thermally stable subsurface and surface ice. The preliminary results show that the measured ranges of brightness roughness from high-resolution NAC images differ in areas with modeled surface ice, subsurface ice, and no ice. The LROC-derived roughness in the region with surface ice is significantly lower than that from other areas with subsurface ice or no ice. These results indicate that high roughness values likely disappear with the existence of surface ice. This correspondence may result from processes such as enhanced ice-rich regolith transport, preferential ice trapping in depression, or changes in surface reflectance.