Photometric properties of Mars soils analogs

Pommerol, Antoine; Thomas, Nicolas; Jost, Bernhard; Beck, P.; Okubo, C.; McEwen, A. S. (2013). Photometric properties of Mars soils analogs. Journal of Geophysical Research: Planets, 118(10), pp. 2045-2072. Wiley 10.1002/jgre.20158

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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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Pommerol, Antoine; Thomas, Nicolas and Jost, Bernhard

Subjects:

500 Science > 530 Physics

ISSN:

2169-9097

Publisher:

Wiley

Language:

English

Submitter:

Cléa Serpollier

Date Deposited:

13 Aug 2014 11:46

Last Modified:

06 Dec 2014 06:41

Publisher DOI:

10.1002/jgre.20158

BORIS DOI:

10.7892/boris.45644

URI:

https://boris.unibe.ch/id/eprint/45644

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