Theoretical prediction on the global surface temperature map of the Moon. (January 2020)

• Record Type: Journal Article
• Authors: Kim, Taig Young
• Is Part Of: Acta astronautica. Volume 166(2020)
• Page Start: 218
• Page End: 226
• Publication Date: 2020-01
• Subjects: Surface temperature of the Moon -- Lumped System Model -- Thermophysical properties of regolith; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2019.10.022
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: Several studies on lunar surface temperature have been published using temperature measurements from the Diviner Lunar Radiometer Experiment (DLRE) mounted on the Lunar Reconnaissance Orbiter (LRO). The recent study by Williams et al. [1] has provided a detailed temperature map of the entire lunar surface and provides a good opportunity to utilize it. Theoretically, in order to predict the lunar surface temperature, thermophysical properties of the regolith layer are indispensable. However, since the data are limited to those taken at the landing site, a new method is necessary to generate the global temperature map. In this study, a theoretical method to calculate temperature on the global lunar surface was proposed with comparable accuracy to the DLRE measurements without utilizing such thermophysical properties. The energy equation of the Lumped System Model (LSM) for the very thin uppermost lunar regolith layer was established, and the mathematical formulation of the bottom conductive heat flux required to solve the LSM equation was proposed using the appropriate theory. Based on recent work on the DLRE, the LSM equation was analyzed, assuming that thermal mass per unit area, which is only one integral thermophysical property of the LSM, is globally homogeneous over the Moon. The thermal mass per unit area and the coefficients of the suggested bottom conductive heat flux were extracted from DLRE measurements and optimized through best curve fitting to DLRE measurements. The temperatures predicted by LSM are reasonably accurate, and the mean temperature difference from the DLRE measurements in latitudes equatorward of 70° is only 3.15 K. The global surface temperature map reproduced by the LSM analysis is a good match with the map extracted from DLRE measurements, except in anomalous temperature zones caused by surface topology and rock abundance. Highlights: Mathematical prediction of global surface temperature of the Moon using new method. Lumped System Model with bottom conductive heat flux to solve the energy equation. The temperature map generated by the LSM is a good match with DLRE measurements.