Some Recent Developments in Radiative Transfer Computation

This keynote focuses on recent development of my own research group on the discovery and re-examination of numerical errors and their physical meanings in the discretization and solution of the integro-differential equation of radiation transfer. Among discretization-based numerical methods, such as the discrete-ordinates and the finite-volume methods, two shortcomings were well known, i.e., false scattering and ray effect. We will see that the so-called “false scattering” actually affects the attenuation term, i.e., both absorption and out-scattering. Both “false scattering” and ray effect errors exhibit dependence on both spatial and angular discretization. In radiation transfer in anisotropic scattering media, errors due to alteration of the asymmetry factor and phase function exist due to angular discretization; and they cause false in-scattering. The error in discretized asymmetry factor can be corrected via Hunter and Guo’s methods of phase function normalization.