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Chang’E‐4 Rover Spectra Revealing Micro‐scale Surface Thermophysical Properties of the Moon
Author(s) -
Wu Yunzhao,
Kührt Ekkehard,
Grott Matthias,
Jin Qi,
Xu Tianyi,
Helbert Jörn,
Hamm Maximilian,
Qin Nannan,
Ma Jinsong,
Vincent JeanBaptiste,
Hayne Paul
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl089226
Subject(s) - regolith , infrared , remote sensing , orbiter , wavelength , azimuth , thermal , radiation , surface roughness , geology , optics , astrobiology , physics , astronomy , meteorology , quantum mechanics
Abstract Lunar surface temperature variations provide key information about the thermophysical properties of the regolith. To date, temperatures have been measured using telescopes and orbiter instruments, providing information from mid‐infrared to long infrared (IR) wavelengths. Here, we report on temperature measurements in the short‐wavelength IR at centimeter scales observed in situ by the Chang’E‐4 rover. These local observations are an important complement to the existing large‐scale data. We show that even at 2.39 µm, where reflected radiation dominates the spectrum, thermal information can be retrieved from the data. The observed thermal radiances and derived temperatures depend on the observation geometry, specifically the relative azimuth angle between Sun and detector. This indicates that surface roughness on subresolution (millimeter) scales causes a non‐Lambertian radiation pattern of the emitted flux that is per definition independent of the observation angle. This behavior must be considered when deriving temperatures and thermal properties of lunar regolith.