Deriving the Absolute Reflectance of Lunar Surface Using SELENE (Kaguya) Multiband Imager Data

Abstract

The absolute reflectance of the Moon has long been debated because it has been suggested (Hillier et al. in Icarus 151:205-225, 1999) that there is a large discrepancy be-M. Ohtake ( ) · T. Morota · J. Haruyama · H. Otake 58 M. Ohtake et al.tween the absolute reflectance of the Moon derived from Earth-based telescopic data and that derived from remote-sensing data which are calibrated using laboratory-measured reflectance spectra of Apollo 16 bulk soil 62231. Here we derive the absolute reflectance of the lunar surface using spectral data newly acquired by SELENE (Kaguya) Multiband Imager and Spectral Profiler. The results indicate that the reflectance of the Apollo 16 standard site, which has been widely used as an optical standard in previous Earth-based telescopic and remote-sensing observations derived by Multiband Imager, is 47% at 415 nm and 67% to 76% at 750 to 1550 nm of the value for the Apollo 16 mature soil measured in an Earth-based laboratory. The data also suggest that roughly 60% of the difference is caused by the difference in soil composition and/or maturity between the 62231 sampling site and the Apollo 16 standard site and that the remaining 40% difference can be explained by the difference between the compaction states of the laboratory and the actual lunar surface. Consideration of the compaction states of the surface soil demonstrates its importance for understanding the spectral characteristics of the lunar surface. We also explain and evaluate data analysis procedures to derive reflectance from Multiband Imager data.Keywords Moon · Kaguya · SELENE · Multiband Imager · Reflectance Abbreviations A16StSApollo 16 standard site used by Clementine UVVIS camera as an optical standard site; located about 10 km west of the Apollo 16 landing site. MI or SP or ROLO data of A16StS is denoted as MI or SP or ROLO A16StS. The number after A16StS indicates the observation number for MI and SP corrected RLab62231 RLab62231 corrected using the correction factors in Hillier et al. (1999) Diff lab-MI Difference of reflectance spectra between RLab62231 and MI A16StS Diff lab-EbtDifference of reflectance spectra between RLab62231 and Earth-based telescopic data in Shorthill et al. (1969)

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