Characterizing Lunar Regolith at the Chang’E-3 Landing Site with an Improved Microphysical Photometric Model

Abstract The physical properties of lunar regolith, such as particle size, complex refractive index, single scattering albedo (SSA), and scattering asymmetry parameter, are crucial for understanding space weathering processes on the Moon. Here, we apply an improved microphysical photometric model (M-XZL), which accounts for both shadow-hiding and coherent-backscatter opposition effects, to in situ reflectance observations from the Chang’E-3 (CE-3) panoramic camera. We extract these parameters and investigate the photometric characteristics of the surface regolith at the CE-3 landing site. The retrieved SSA value of approximately 0.7 is significantly higher than those reported in previous studies based on the Hapke model. This may suggest either a lower degree of space weathering at the site, or an overestimation of the absorptive effect of space weathering products (e.g., nanophase iron), or both. These findings may indicate a slower regolith maturation rate and provide improved constraints on models of lunar surface evolution.