Diffuse reflectance of the ocean: some effects of vertical structure

Monte Carlo computations of the diffuse reflectance of an ocean consisting of two homogeneous layers with differing optical properties are presented, along with a simplified method of computation that uses results of previous Monte Carlo simulations. It is demonstrated that it is impossible to distinguish between thin layers of strong scattering and thick layers of weak scattering through measurement of the diffuse reflectance. Analyzing the two-layer reflectance under the assumption of a homogeneous ocean yields an optical property that is shown to be nearly the average of the associated property over the penetration depth of the medium, i.e., the depth over which the downwelling irradiance falls to l/e of its value at the surface.