Characterizing Thermal Anomaly in Pierazzo Crater Based on CELMS and Multispectral Data

Abstract

Based on Chang’e-2 lunar microwave sounder (CELMS) data, this letter reveals a significant lunar cold spot in the Pierazzo impact crater (3.3°N, 100.24°W) on the far side of the moon. By integrating brightness temperature (TB) distribution, surface parameters [ilmenite content, rock abundance (RA), albedo], and loss tangent, we obtain these following results: first, we identify Pierazzo crater as a cold spot, exhibiting significantly lower nighttime TB across all four frequencies compared with its surroundings. Then, this TB anomaly is primarily influenced by a high loss tangent value, which indicates that regolith porosity increases with depth due to rock fragmentation induced by impact, thereby enhancing the thermal resistance effect. Next, this thermophysical anomaly exhibits secondary contributions from albedo and RA. Finally, asymmetric thermal response between eastern and western regions suggests subsurface material heterogeneity.