Open AccessThermal removal from near‐infrared imaging spectroscopy data of the Moon
Author(s) -
Clark Roger N.,
Pieters Carlé M.,
Green Robert O.,
Boardman J. W.,
Petro Noah E.
Publication year - 2011
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010je003751
Subject(s) - emissivity , infrared , spectroscopy , materials science , emission spectrum , optics , thermal , thermal infrared spectroscopy , wavelength , infrared spectroscopy , pyroxene , spectral line , remote sensing , physics , mineralogy , geology , astronomy , meteorology , olivine , quantum mechanics
In the near‐infrared from about 2 μ m to beyond 3 μ m, the light from the Moon is a combination of reflected sunlight and emitted thermal emission. There are multiple complexities in separating the two signals, including knowledge of the local solar incidence angle due to topography, phase angle dependencies, emissivity, and instrument calibration. Thermal emission adds to apparent reflectance, and because the emission's contribution increases over the reflected sunlight with increasing wavelength, absorption bands in the lunar reflectance spectra can be modified. In particular, the shape of the 2 μ m pyroxene band can be distorted by thermal emission, changing spectrally determined pyroxene composition and abundance. Because of the thermal emission contribution, water and hydroxyl absorptions are reduced in strength, lowering apparent abundances. It is important to quantify and remove the thermal emission for these reasons. We developed a method for deriving the temperature and emissivity from spectra of the lunar surface and removing the thermal emission in the near infrared. The method is fast enough that it can be applied to imaging spectroscopy data on the Moon.