Detailed validation of the bidirectional effect in various Case 1 waters for application to ocean color imagery
1Department of Physics, University of Miami, Coral Gables, Florida, USA
2Laboratoire d'Océanographie de Villefranche, Université Pierre et Marie Curie et Centre National de la Recherche Scientifique, Villefranche-sur-mer, France
Abstract. The radiance viewed from the ocean depends on the illumination and viewing geometry along with the water properties, and this variation is called the bidirectional effect. This bidirectional effect depends on the inherent optical properties of the water, including the volume scattering function, and is important when comparing data from different satellite sensors. The current model of f/Q, which contains the bidirectional effect, by Morel et al. (2002) depends on modeled, not measured, water parameters, thus must be carefully validated. In this paper we combined upwelling radiance distribution data from several cruises, in varied water types and with a wide range of solar zenith angles. We compared modeled and measured Lview/Lnadir and found that the average difference between the model and data was less than 0.01, while the RMS difference between the model and data was on the order of 0.02–0.03. This is well within the statistical noise of the data, which was on the order of 0.04–0.05, due to environmental noise sources such as wave focusing.
Voss, K. J., Morel, A., and Antoine, D.: Detailed validation of the bidirectional effect in various Case 1 waters for application to ocean color imagery, Biogeosciences, 4, 781-789, doi:10.5194/bg-4-781-2007, 2007.