Analyzing the microwave thermal emission features of lunar regolith in Chang’E landing sites and its geologic significance
Abstract
<p indent="0mm">The <italic>in situ</italic> lunar regolith explorations of Chang’E 3, 4, and 5 landing sites provide an essential reference for lunar research based on microwave radiometer (MRM) data from Chang’E 1 and 2 satellites. To eliminate the influence of the brightness temperature with latitude and highlight the relationship between the brightness temperature and the lunar regolith composition, the normalized brightness temperature and the brightness temperature difference maps were defined and produced. Based on Kaguya MI data, FeO, TiO<sub>2</sub>, clinopyroxene, and olivine abundances of Chang’E 3, 4, and 5 landing sites were calculated. Combined with the <italic>in situ</italic> exploration results, the microwave thermal emission properties of the regolith in Chang’E 3, 4, and 5 landing regions were systematically analyzed. The main findings are as follows: (1) the Chang’E 5 landing region has a stable brightness temperature performance, indicating that the variation of the lunar regolith composition with depth is insignificant in this area, which can be used as an essential reference for microwave thermal radiation anomaly research. (2) A stratified structure exists within the lunar regolith detection range of the Chang’E 3 landing region. With the lower, middle, and upper layers represented by the low-frequency data, high-frequency data, and optical results, respectively, the composition significantly changes. (3) Cold microwave anomalies were found and proposed in the Chang’E 4 landing region, and its nature and formation were preliminarily analyzed. The results show that microwave radiometer data can be used for identifying mare basalt, which can provide an important scientific reference for deepening future studies on the evolution of lunar mare magma.</p>
