Contribution to Sandy Site Characterization:
Spectro-Directional Signature, Grain Size Distribution and
Mineralogy Extracted from Sand Samples

Françoise Viallefont-Robinet, Cédric Bacour, Marc Bouvet, Malika Kheireddine, Mustapha Ouhssain, Ramzi Idoughi, Léo Grignon, Eric Munesa, François Lemaître and Thomas Rivière.
Remote Sensing (2019)

Spectro-Directional signature characterization of a sand sample collected in a Pseudo-Invariant Calibration Sites (PICS).
(left) Sand sample: Arabia_PICSAND1_SPL5; (middle) Measurement device: ONERA BCRF measurement device named "Banc de BRDF grands échantillons"; (right) Comparison of three measurments of the BCRF for three different positions (illustration of the uncertainity for Arabia_PICSAND1_SPL5).


The characterization of sands detailed in this paper has been performed in order to support the in-flight radiometric performance assessment of space-borne optical sensors over the so-called Pseudo-Invariant Calibration Sites (PICS). Although the physical properties of PICS surface are fairly stable in time, the signal measured from space varies with the illumination and the viewing geometries. Thus, there is a need to characterize the spectro-directional properties of PICS. This could be done on a broad scale, thanks to multi-spectral multi-directional space-borne sensors such as the POLDER instrument (with old data). However, interpolating or extrapolating the spectro-directional reflectance measured from space to spectral bands of another sensor is not straightforward. The hyperspectral characterization of sand samples collected within or nearby PICS could contribute to a solution. In this context, a set of 31 sand samples was compiled. The BiConical Reflectance Factor (BCRF), linked to Bidirectional Reflectance Distribution Function (BRDF), was measured between 0.4 and 2.5 um, over a half hemisphere when the amount of sand in the sample was large enough and for only a single fixed angular configuration for small samples. These optical measurements were complemented by grain size distribution measurements and mineralogical analysis and compiled together with previously published measurements in the so-called PICSAND database, freely available online.


paper: [viallefont2019contribution.pdf (11.9MB)] 
Dataset: The dataset can be downloaded from the dedicated web portal 
  title={Contribution to sandy site characterization: spectro-directional signature, grain size distribution and mineralogy extracted from sand samples},
  author={Viallefont-Robinet, Fran{\c{c}}oise and Bacour, C{\'e}dric and Bouvet, Marc and Kheireddine, Malika and Ouhssain, Mustapha and Idoughi, Ramzi and Grignon, L{\'e}o and Munesa, Eric and Lema{\^\i}tre, Fran{\c{c}}ois and Rivi{\`e}re, Thomas},
  journal={Remote Sensing},
  publisher={Multidisciplinary Digital Publishing Institute}