Modelling of the optical contrast of an oil film on a sea surface

The water-leaving radiance field above a sea surface polluted by an oil fil m has been modelled using a Monte Carlo radiative transfer technique with l arge numbers of photons incident at a selected zenith angle. The calculated radiance was recorded for each of the 240 sectors of equal solid angle the upper hemisphere had been divided into. The results are presented in the f orm of a bi-directional reflectance distribution function (BRDF) and as a c ontrast function parameterised by observation angle for various angles of i ncident sunlight and for various states of the sea surface roughness. The c onditions for observing maximal and minimal contrast are described. (C) 200 1 Optical Society of America.