EigenFlux: A Stable Multi-Stream Radiative Transfer Method for Strongly Backward-Scattering Media

Abstract. The radiative transfer (RT) of light and radiation through a medium such as an atmosphere, pigment, or water is of interest to many research communities, such as atmospheric physics and chemistry, metereology, climate research, astronomy, remote sensing, painting and coating material science, oceanography, hydrology, and graphics rendering. Despite its many uses, to the best of our knowledge there is not a non-commercial multi-stream algorithm capable of handling strongly backwards scattering systems with asymmetries in excess of -0.95. In this paper we present an derivation and implementation of the EigenFlux system which incorporates use of a Mesh Approximates multistream and eigenvalue decomposition with numerical stability achieved through the use of a natural reflectance condition. We conclude with numerical demonstrations of the range and precision of the method.