title: Depolarization of polarized light caused by high altitude clouds. 1: Depolarization of lidar induced by cirrus.
abstract: A scattering model is described for the investigation of depolarization of polarized light caused by ice clouds. The scattering by a single particle is described by refraction, reflection, and diffraction. The ice cloud is assumed to be a random mixture of hexagonal columns and plates of random orientation and size. Multiple scattering effects are included by means of a Monte Carlo method, where single photon histories are constructed from random samples of the distributions governing the basic scattering parameters. The dependence of depolarization on cloud extinction coefficient, receiver field of view, and mixing ratio of columns to plates are studied. Lidar measurements of depolarization by a high altitude cirrus cloud are presented and discussed within the frame of the present model. Good agreement can be obtained assuming a variation of crystal shape distribution with height.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Sun
authors.forename: Z P
authors.initials: ZP
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Bösenberg