Publication
Reference
Andrieu François, Schmidt Frédéric, Schmitt Bernard, Douté Sylvain, Brissaud Olivier (2015). Radiative transfer model for contaminated slabs: experimental validations. Cryosphere Disc., 9, 5137 - 5169.
Names
  • François Andrieu
  • Frédéric Schmidt
  • Bernard Schmitt
  • Sylvain Douté
  • Olivier Brissaud
Article and keywords
Title
Radiative transfer model for contaminated slabs: experimental validations
Abstract
This article presents a set of spectro-goniometric measurements of different water ice samples and the comparison with an approximated radiative transfer model. The experiments were done using the spectro-radiogoniometer described in Brissaud et al. (2004). The radiative transfer model assumes an isotropization of the flux after the second interface and is fully described in Andrieu et al. (2015). Two kinds of experiments were conducted. First, the specular spot was closely investigated, at high angular resolution, at the wavelength of 1.5 μm, where ice behaves as a very absorbing media. Second, the bidirectional reflectance was sampled at various geometries, including low phase angles on 61 wavelengths ranging from 0.8 to 2.0 μm. In order to validate the model, we made qualitative tests to demonstrate the relative isotropization of the flux. We also conducted quantitative assessments by using a Bayesian inversion method in order to estimate the parameters (e.g., sample thickness, surface roughness) from the radiative measurements only. A simple comparison between the retrieved parameters and the direct independent measurements allowed us to validate the model. We developed an innovative Bayesian inversion approach to quantitatively estimate the uncertainties in the parameters avoiding the usual slow Monte Carlo approach. First we built lookup tables, and then we searched the best fits and calculated a posteriori density probability functions. The results show that the model is able to reproduce the geometrical energy distribution in the specular spot, as well as the spectral behavior of water ice slabs. In addition, the different parameters of the model are compatible with independent measurements.
Keywords
spectroscopy, optics, numerical model, spectro-gonio radiometer, radiative transfer simulation, bidirectional reflection, bidirectional reflectance spectra, specular reflectance spectra, BRDF, spectra inversion, visible, near-IR, ice, snow, H2O, grain size, surface roughness, layer thickness, surface, Earth
Content
sample, spectral data, BRDF data, earth sciences
Year
2015
Journal
The Cryosphere discussion
Volume
9
Pages
5137 - 5169
Pages number
13
Document type
discussion
Publication state
published
Doi
10.5194/tcd-9-5137-2015
Identifiers
Publications