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Etude photométrique de la surface de Mars à partir de la caméra HRSC à bord de la sonde Mars Express
Préparation aux observation orbitale multi-angulaire en exploration planétaire.

Abstract : One of the new investigations from orbit that can be addressed with the multi-angular HRSC/ Mars-Express dataset generated with the nadir-looking, stereo and photometric channels,
is to derive the surface photometric characteristics for mapping the variation of the soil/bedrock physical properties of Mars, and to relate them to the spectroscopic and thermal observations produced by OMEGA, TES and THEMIS instruments.
Minnaert and two-term phase function Hapke models concur to demonstrate that HRSC multi-angular observations acquired over Gusev crater and Apollinaris southern flank along the ongoing Mars-Express mission can be, under some limitations, pieced together to derive integrated phase functions over a wide range of phase angles (5-95°) at moderate spatial resolution on the order of 400 m-1.6 km.

In combination with the surface roughness variation, the opposition effect appears to play a significant role suggesting that the surface state optical properties across Gusev
are strongly influenced by the porosity and packing characteristics of the upper layer of the Martian regolith. The mapping aspect of the present photometric investigation is quite useful to get a better sense of the meaning of the observed variations.
Given the overall patterns derived from this analysis, it is quite likely that the observed photometric variation at least for the western and central part of Gusev crater is partly driven by the prevailing wind regimes considered to be oriented north-northwest / south-southeast and disturbing the very upper surface layer.
The present photometric results agree with independent investigations based on orbital thermal inertia and reflectance spectroscopy, and on in situ photometric and microscopic imaging data returned by Spirit instruments. It supports the idea of a thin layer of fine-grained dust being stripped off in the low albedo units to reveal a dark basaltic substrate comprising coarse-grained materials.
These results open new possibilities for documenting planetary surface processes.
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https://tel.archives-ouvertes.fr/tel-00276278
Contributor : Williams Exbrayat <>
Submitted on : Tuesday, April 29, 2008 - 11:51:37 AM
Last modification on : Thursday, October 15, 2020 - 4:07:04 AM
Long-term archiving on: : Friday, May 28, 2010 - 5:59:05 PM

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  • HAL Id : tel-00276278, version 1

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Augustin Jehl. Etude photométrique de la surface de Mars à partir de la caméra HRSC à bord de la sonde Mars Express
Préparation aux observation orbitale multi-angulaire en exploration planétaire.. Planète et Univers [physics]. Université Paul Sabatier - Toulouse III, 2008. Français. ⟨tel-00276278⟩

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