Photometric properties of Mars soils analogs

A. Pommerol, N. Thomas, B. Jost, P. Beck, C. Okubo, Alfred S. McEwen

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries. Key Points Effects of surface texture on the bidirectional reflectance of dry samples Photometric signatures of liquid water in soils

Original languageEnglish (US)
Pages (from-to)2045-2072
Number of pages28
JournalJournal of Geophysical Research: Space Physics
Volume118
Issue number10
DOIs
StatePublished - Oct 2013

Fingerprint

mars
Mars
soils
analogs
Soils
Water
soil
bidirectional reflectance
Textures
texture
water
textures
Forward scattering
Photometry
liquid
Ice
Liquids
sample preparation
Backscattering
polar region

Keywords

  • Analogs
  • Mars
  • Photometry
  • Soils

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Photometric properties of Mars soils analogs. / Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, Alfred S.

In: Journal of Geophysical Research: Space Physics, Vol. 118, No. 10, 10.2013, p. 2045-2072.

Research output: Contribution to journalArticle

Pommerol, A, Thomas, N, Jost, B, Beck, P, Okubo, C & McEwen, AS 2013, 'Photometric properties of Mars soils analogs', Journal of Geophysical Research: Space Physics, vol. 118, no. 10, pp. 2045-2072. https://doi.org/10.1002/jgre.20158
Pommerol, A. ; Thomas, N. ; Jost, B. ; Beck, P. ; Okubo, C. ; McEwen, Alfred S. / Photometric properties of Mars soils analogs. In: Journal of Geophysical Research: Space Physics. 2013 ; Vol. 118, No. 10. pp. 2045-2072.
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