VDISORT: An improved and generalized discrete ordinate method for polarized (vector) radiative transfer

A previously developed model for vector discrete ordinate radiative transfer in vertically inhomogeneous plane parallel media has been tested for both Rayleigh and Mie scattering phase matrices. A few errors were found in the implementation of the model that seriously impaired the model output. An improved version of the model was created in which the errors have been corrected. In addition, the procedure for computing the Fourier components of the phase matrix, required as input to the radiative transfer routines, has been replaced by a more efficient and accurate procedure. While the original version of the model was limited to phase matrices of spherical particles or to scatterers much smaller than the wavelength of the incident light (Rayleigh limit), the new version presented here is valid for a much broader range of applications including scattering by an ensemble of nonspherical particles. Extensive tests of the model in the Rayleigh limit as well as for unpolarized and polarized beam source applications in the Mie regime demonstrate the significant improvements in accuracy and efficiency achieved with the new version.