Biogeosciences
www.biogeosciences.net
1726-4170
1726-4189
4
5
2007
10.5194/bg-4-781-2007
http://www.biogeosciences.net/4/781/2007/
http://www.biogeosciences.net/4/781/2007/bg-4-781-2007.html
http://www.biogeosciences.net/4/781/2007/bg-4-781-2007.pdf
781
789
2007-09-26
Detailed validation of the bidirectional effect in various Case 1 waters for application to ocean color imagery
K. J. Voss
voss@physics.miami.edu
A. Morel
D. Antoine
Department of Physics, University of Miami, Coral Gables, Florida, USA
Laboratoire d'Océanographie de Villefranche, Université Pierre et Marie Curie et Centre National de la Recherche Scientifique, Villefranche-sur-mer, France
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 <i>f/Q</i>, 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
<i>L</i><sub>view</sub>/<i>L</i><sub>nadir</sub> 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.
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