Uncertainty in the bidirectional reflectance model for oceanic waters





Citation of Original Publication

Peng-Wang Zhai, Yongxiang Hu, Charles R. Trepte, David M. Winker, Patricia L. Lucker, Zhongping Lee, and Damien B. Josset, "Uncertainty in the bidirectional reflectance model for oceanic waters," Appl. Opt. 54(13) (01 May 2015) 4061-4069. https://doi.org/10.1364/AO.54.004061


This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
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We study the impacts of the bio-optical model variations on the angular distribution (𝑓/𝑄 factor) of the upwelling radiance field in ocean waters. An ocean water bio-optical model has been combined with a vector radiative transfer model to calculate the 𝑓/𝑄 factors systematically. The 𝑓/𝑄 factors are compared to those in [Appl. Opt. 41, 6289 (2002) [CrossRef] ] and the differences are found to be within ±10% for 81% of the total number of cases covering all wavelengths, chlorophyll a concentrations, and solar and viewing geometries. The differences are attributed to the choice of ocean water scattering function and scattering coefficient biases. In addition, we study the uncertainty of 𝑓/𝑄 factor due to three factors: (I) the absorption coefficient of the colored dissolved organic matter (CDOM), (II) the particle scattering coefficient, and (III) the ocean water depolarization. The impacts of ocean water depolarization on the 𝑓/𝑄 variation is found to be negligible. If we perturb the CDOM absorption coefficient by a factor ranging from 0.1 to 10, the 𝑓/𝑄 values vary within ±5% of the average behavior of ocean waters for 93% of the cases. If we perturb the scattering coefficients by a factor ranging from 0.5 to 2.0, the 𝑓/𝑄 variation is within ±5% for 81% of the cases studied. This work contributes to understanding the uncertainty of ocean color remote sensing.