Inversions of subsurface temperature and thermal diffusivity on the Moon based on high frequency of Chang’E-1 microwave radiometer data

Abstract

Thermal behavior of regolith reflects its thermophysical properties directly on the Moon. In this study, we employed the Fourier temperature model and inverted mean subsurface temperature and thermal diffusivity from high frequency of Chang’E-1 microwave radiometer data. The result showed that the mafic lunar mare endured higher thermal regime than that of feldspathic highland in a lunar cycle. As expected, the highland diffusivity with mean value 2.5 × 10−4 cm2/s is greater than the mean value 0.3 × 10−4 cm2/s of lunar mare. It indicated that the highland material responded more quickly than that of lunar mare to the changes of surface temperature in a diurnal day. In addition, thermal anomalous regions and hot/cold spots were also identified by diffusivity. For the thermal anomalous regions, Mare Tranquillitatis for example, with more contents of (FeO+TiO2), agglutinate and high maturity index corresponded to greater diffusivity (∼1.0 × 10−4 cm2/s) and is more sensitive to the variations of temperature than the neighboring Mare Serenitatis (∼0.3 × 10−4 cm2/s). Thus, inversion and comparison of regolith thermophysical properties can reveal more information of geological evolution on the Moon.