Evaluation of a Hyperspectral Optical - Monte Carlo Remote Sensing Model in a Water Tank Study

A physical hyperspectral optical - Monte Carlo (PHO-MC) model for computing reflectance from a body of water is evaluated in a water tank experiment. Reflectance calculation in the model is simulated based on Monte Carlo simulations of photon packet paths in three dimensions. Simulated reflectance was compared with the measured reflectance. The model was evaluated for varied depths of water and different characteristics of the tank bottom. Significant differences were found in the measured reflectance even for clear water due to change in water depth and bottom reflectance characteristics of the water tank. The model reproduced measured reflectance over the entire spectral region extending from 400 to 800 nm for these varied conditions. Model calculation showed that the effect of diffuse radiation and its specular reflection from the air-water interface contribute significantly to reflectance. The relative error in predicted reflectance for all 41 wavelengths evaluated in this study increased from 5.2% to 25.4% when diffuse radiation and its specular reflections were ignored in the model formulation.