Diffuse reflectance of the optically deep sea under combined illumination of its surface

The processing of remotely measured color imagery involves knowledge of the diffuse reflectance of the oceanic water. This paper presents two approaches to this problem. The first one is analytical and consists of an approximate solution to the radiative transfer equation. As a result it gives an equation for diffuse reflectance of the sea as a function of inherent optical properties, the Sun elevation angle and the ratio of the direct illumination by Sun to the diffuse illumination by sky. The second approach is a numerical Monte Carlo simulation. The results of this simulation are processed to produce regressions that connect diffuse reflectance of the seawater for different hydrooptical situations to the solar elevation angle