Radiance Distribution of Sunlight Reflected from a Shadowed Sea*

Results for the actual radiance distribution of light are obtained numerically using the in situ measured optical properties of seawater. The scattering phase function is estimated through the regression equations that are based on all fifteen Petzold scattering phase functions. The derived scattering phase function depends the scattering coefficient, the single-scattering albedo, and the scattering angle. The final result is an expression for the upwelling sea angular radiance distribution as a function of: the sun zenith angle, azimuthal and zenith angles of viewing, the width of the opaque body, absorption and attenuation coefficients, and the phase function of scattering. The resulting radiance distributions are discussed and illustrated. Detailed quantitative interpretations of images sometimes require data about the angular distribution of light reflected from a shadowed sea. We derive the solution of the two-dimensional radiative transfer problem for the sea shadowed by an opaque body such as a pier. The solution of the problem requires two different theoretical approaches: one for the depth dependence and one for the horizontal field. The solution for the depth dependence i