Comprehensive assessment of the two-flow model’s shape factors in aquatic environments

Abstract

The applicability of the two-flow model to problems is dependent on assumptions that are used to reduce the model to two equations with two unknowns. Such a reduction requires proper parameterization of the shape factors. An extensive data set that reveals the relationships of shape factors to scattering-to-absorption ratios (0.1 < or = b/a < or = 30) and to the mean cosine of scattering (0.66 < or = micro(s) < or = 0.95) as obtained with a Monte Carlo model is presented. The sensitivity of the computed irradiance reflectance to the shape factors is also addressed. Results show increasing sensitivity of irradiance reflectance to the shape factors with increasing scattering-to-absorption ratio and with increasing anisotropy of the scattering phase function. For waters with highly anisotropic scattering phase functions, high scattering-to-absorption ratios, or both, the proper parameterization of the shape factors must be considered. A lookup table of the shape factors' depth-dependent values for various optical conditions is also presented.