“…Most, if not all, plane-parallel techniques have been extended to the spherical case. This includes the Monte Carlo method [1, 5, 7, 11, 13, 15, 25, 27, 29, 31, 32, 62, 63, 66-69, 81, 97] , discrete ordinates [2,12,16,17,24,[73][74][75][82][83][84] including low number of streams approximation [46,90,94] , two [60] and successive orders of scattering [6,21,43,59,87,96] , Gauss-Seidel iterations [23,34,52] , source integration for the first order of scattering [18,[91][92][93] , combined differential-integral approach [70][71][72] , finite-difference and addingdoubling [33] , invariant imbedding [3] , Eddington [89] , Picard iteration [19] , small-angle modification [22] , and Markov chain [95] . Only Monte Carlo models can simulate multiple scattering in true spherical geometry, while the other models can only offer corrections to the plane-parallel approach (pseudo-sphericity).…”