Publication
Reference
Pommerol A., Schmitt B. (2008). Strength of the H2O near-infrared absorption bands in hydrated minerals: Effects of particle size and correlation with albedo. J. Geophys. Res. E, 113, E10009.
Names
  • A. Pommerol
  • B. Schmitt
Article and keywords
Title
Strength of the H2O near-infrared absorption bands in hydrated minerals: Effects of particle size and correlation with albedo
Abstract
We use laboratory experiments and radiative transfer modeling to study how the 1.9- and 3-μm H2O absorption bands are affected by variations of mineral particle size and albedo. A consistency between results of physical experiments and numerical simulations demonstrates that the studied effects are well described by the theory of radiative transfer in particulate media. Band strengths show different relationships with particle size, depending on the absolute intensity of the absorption and the criterion used to calculate band strength (band depth, area, ESPAT function, etc.). Various mixing processes used to vary sample albedo reveal a strong dependence of band strengths with albedo. For the 1.9-μm band, those effects result in variations of the hydrated minerals detection limit by more than 1 order of magnitude. However, the shape of the relationship between the 1.9-μm band strength and albedo could be used to get information on the mixing mode (intimate, granular, or geographic) between hydrated and nonhydrated minerals. For the 3-μm band, we found a strong linear correlation between the integrated band area and the continuum reflectance that opens a promising way to isolate the effect of albedo on planetary surfaces and retrieve spatial variations of material hydration state. When this spectral criterion is used for the 3-μm band, the effects of particle size are very limited for particles larger than 150 μm but remain important below this value. Therefore, an independent way to derive particle size from remote sensing appears necessary to address the effects of particle size variations where small particles are present.
Keywords
spectroscopy, bidirectional reflection, radiative transfer simulation, bidirectional reflectance spectra, band intensity, band integrated intensity, mechanical process, grain size, adsorption, near-IR, mineral, smectite Swy-2, smectite STx-1, basaltic volcanic tuff, immature coal PSOC 1532, anthracite coal PSOC 1468, gypsum, H2O, Mars
Content
instrument-technique, sample, material-matter, spectral data, planetary sciences, earth sciences
Year
2008
Journal
Journal of Geophysical Research - Planets
Volume
113
Number
E10
Pages
E10009
Pages number
33
Document type
article
Publication state
published
Doi
10.1029/2007JE003069
Identifiers
Publications