Photon Transport in 3D Structures Treated by Random Walk Techniques. Monte Carlo Benchmark of Ocean Colour Simulations.

The analysis of sun light penetrating atmospheres and oceans constitutes a pertinent problem in climatic research and in the development of algorithms for the retrieval of bio-geo-chemical parameters of suspended matter and dissolved pollutants from remotely sensed ocean colour data. On the basis of the neutron transport code TIMOC a visible and near-infrared photon transport code, called PHO-TRAN, has been developed and tested against a benchmark of existing models. The photon transport allows for reflection, refraction, absorption and all relevant light-scattering processes, in quite general 3D geometries. The scores are flux, radiance, irradiance, averaged over regions or surfaces as well as point detectors. In some cases it is also possible to solve the adjoint problem, as for example in the case of strongly collimated light sensors and extended sources, when evaluating sensor shadowing by nearby complex geometry structures. PHO-TRAN offers unique posibilities to sample first order derivatives of almost all responses with respect to certain input parameters, like material densities and characteristic constants used in scattering models. This paper describes mainly the uniqueness and benchmarking of the developed Monte Carlo procedures.

DOYLE John Piero;  RIEF Herbert; 

1998-09-28

JRC17009

https://publications.jrc.ec.europa.eu/repository/handle/JRC17009,