MONTE-CARLO INTEGRATION OF THE RADIATIVE-TRANSFER EQUATION IN A SCATTERING MEDIUM WITH STOCHASTIC REFLECTING BOUNDARY

A computationally efficient, adaptive algorithm is described for Monte Carlo integration of the radiative transfer equation (RTE) in a scatt ering medium with partially reflecting boundary. The algorithm is form ulated in a general setting with stochastic reflecting boundary, and t he particular case of solar illumination of a rough sea surface is use d to illustrate the general result. The algorithm represents the solut ion of the RTE as a multiple scattering series, involving both interna l scattering and reflection at the boundary. The series is doubly infi nite, and efficient integration of the RTE requires that the dominant terms be identified a priori. This is achieved through the development of a recursive algorithm to assign a priori weights to the terms of t he multiple scattering series. The weights allow the terms to be summe d in order of importance, thereby guaranteeing rapid convergence. (C) 1998 Elsevier Science Ltd. All rights reserved.