Development, importance, and effect of a ground truth correction for the Moon Mineralogy Mapper reflectance data set

Abstract

We evaluate the effect and importance of a ground truth correction for the Moon Mineralogy Mapper (M3) level 2 (reflectance) data set. This correction is derived from extensive laboratory characterizations of mature feldspathic lunar soils and is designed to improve the accuracy of 1 μm absorption features in M3 reflectance data. To evaluate the correction, the band strength across a subset of the feldspathic highlands terrane (FHT) is analyzed with M3 imaging spectroscopy data. Using M3 reflectance data and derived products, we find significant differences in band strength and shape between M3 observations collected over identical terrain but under different observational and operational conditions. The ground truth correction minimizes these differences in 1 μm band strengths and also brings the 1 μm band strengths measured with M3 data into closer agreement with laboratory measurements of lunar soil samples. Although the FHT region studied was found to have very low band strengths, the M3 ground truth correction results in overall stronger absorption features for all mature soils relative to uncorrected level 2 (reflectance) data for the same region. These differences between M 3 data collected under different operational conditions and the effects of the ground truth correction, while minor in appearance, can have significant implications for interpretations of any regional soil analyses with M3 data that rely on absolute 1 μm absorption feature strength. The M3 ground truth correction corrects only wavelengths below ~1500 nm, and comparisons between corrected and uncorrected wavelengths must be done with caution. Key Points Absorption features of 1 μm in the FHT are analyzed with M3 data Variations in band strength under variable M3 operational conditions are found M3 ground truth correction is found to improve band strength accuracy ©2013. American Geophysical Union. All Rights Reserved.