A theoretical foundation is presented for the experimental determination of the scattering-phase matrix for nonspherical ice crystals. The scattering-phase matrix can be determined solely from four radiance measurements. Conditions for the phase matrix of a volume of ice crystals that are typical of those in cirrus clouds are presented.
Kuo-Nan Liou, "Theory of the scattering-phase-matrix determination for ice crystals," J. Opt. Soc. Am. 65, 159-162 (1975)