Abstract
<title>Abstract</title> <p>Recently, Sinha et al. interpreted polarimetric radar signatures from the interiors of some doubly shadowed craters near the lunar South Pole as evidence for subsurface ice. They proposed a combined empirical threshold for radar circular polarization ratio (CPR) and the degree of polarization (DOP) as a refined diagnostic criterion for identifying subsurface ice through volume scattering. We argue instead that these variations in CPR and DOP are fully consistent with different levels of near-surface roughness within these craters, and the proposed threshold values are not a definitive indicator of volume scattering caused by subsurface ice. When observed using fully polarimetric radar data, robust evidence for thick, sheet-like water ice within the lunar poles require a combination of strong linear, circular polarization ratios, and enhanced DOP values, along with a high degree of correlation between radar-bright features and regions of permanent shadow.</p>