Prediction of Radiation Absorption and Scattering in Turbid Water Bodies

Abstract
In this study four methods of solving the radiative transfer equation applied to shallow ponds have been compared. The methods include a simple version of Beer’s law, a representative two-flux model, a six-flux model and the method of discrete ordinates. Calculations have been performed for a wide range of representative conditions typical to natural water. It was found that scattering was unimportant when the scattering albedo is small (ω ≲ 0.5) and the phase function is highly forward peaked. Consequently, even the simple Beer’s law expression yielded accurate predictions. However, in general only the six-flux method provided a suitable compromise between accuracy and operational convenience for all the conditions considered. The two-flux method was found to be the least accurate primarily due to its inability to account for refraction.