Atmos. Chem. Phys. Discuss., 9, 19279-19311, 2009
www.atmos-chem-phys-discuss.net/9/19279/2009/
doi:10.5194/acpd-9-19279-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
High-accuracy measurements of snow Bidirectional Reflectance Distribution Function at visible and NIR wavelengths – comparison with modelling results
M. Dumont1, O. Brissaud2, G. Picard1, B. Schmitt2, J.-C. Gallet1, and Y. Arnaud3
1Laboratoire de Glaciologie et de Géophysique de l'Environnement, 54 rue Molière, 38402 Saint Martin d'Hères cedex, France
2Laboratoire de Planétologie de Grenoble BP 53, 38401 Grenoble Cedex 9, France
3IRD-LTHE, Laboratoire de Glaciologie et de Géophysique de l'Environnement, 54 rue Molière, 38402 Saint Martin d'Hères cedex, France

Abstract. High-accuracy measurements of snow Bidirectional Reflectance Distribution Function (BRDF) were performed for four natural snow samples with a spectrogonio-radiometer in the 500–2600 nm wavelength range. These measurements are one of the first set of direct snow BRDF values over a wide range of lighting and viewing geometry. They were compared to BRDF calculated with two optical models. Variations of the snow anisotropy factor with lighting geometry, wavelength and snow physical properties were investigated. Results show that at wavelengths with small penetration depth, scattering mainly occurs in the very top layers and the anisotropy factor is controlled by the phase function. In this condition, forward scattering peak or double scattering peak is observed. In constrast at shorter wavelengths, the penetration of the radiation is much deeper and the number of scattering events increases. The anisotropy factor is thus nearly constant and decreases at grazing observation angles.

Citation: Dumont, M., Brissaud, O., Picard, G., Schmitt, B., Gallet, J.-C., and Arnaud, Y.: High-accuracy measurements of snow Bidirectional Reflectance Distribution Function at visible and NIR wavelengths – comparison with modelling results, Atmos. Chem. Phys. Discuss., 9, 19279-19311, doi:10.5194/acpd-9-19279-2009, 2009.
 
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