Light scattering by polydisperse, rotationally symmetric nonspherical particles: Linear polarization

Abstract Since most solid particles in the Earth and planetary atmospheres have irregular shapes, quantifying the effects of particle nonsphericity on the results of remote sensing of the atmosphere is an important problem. In this paper, we perform a general theoretical survey of linear polarization of light scattered by polydisperse, randomly oriented, rotationally symmetric particles of size comparable to the wavelength of radiation. Our paper deals with polydispersions of nonspherical particles because (1) averaging light-scattering characteristics over sizes provides more realistic modeling of natural particle ensembles and (2) comparisons of scattering properties of particles of a single size are usually meaningless because of the complicated interference structure and high-frequency ripple of monodisperse scattering patterns. In our computations, we use the T-matrix approach, as extended recently to randomly oriented particles by Mishchenko [ J. Opt. Soc. Amer A 8 , 871 (1991)]. Following Hansen and Travis [ Space Sic. Rev. 16 , 527 (1974)], we assume that the scattering properties of polydisperse particles depend primarily on only the effective size parameter and effective variance of the size distribution, the particular shape of the distribution being of minor importance. Therefore, to describe the dispersion of particle sizes in the ensemble, we employ a convenient power law distribution of particle equivalent-sphere size parameters. Size- averaged light-scattering characteristics are calculated by numerically integrating monodisperse quantities using a Gaussian quadrature formula. The results of extensive numerical calculations for particles of different shape and refractive index are presented in the form of color contour diagrams of linear polarization as a function of scattering angle and effective equivalent-sphere size parameter. The influence of particle size distribution, shape, and refractive index on the polarization patterns is examined in detail and implications for polarimetric remote sensing of nonspherical aerosols are discussed. The diagrams displayed include calculations for over 150,000 different monodisperse particles in rndom orientation with equivalent-sphere size parameters up to 30 and may be used to interpret results of laboratory measurements and remote observations of light scattering by small particles.

[1]  D. Huffman,et al.  Experimental determinations of Mueller scattering matrices for nonspherical particles. , 1978, Applied optics.

[2]  S. C. Hill,et al.  Light Scattering by Particles: Computational Methods , 1990 .

[3]  Makoto Sato,et al.  Cloud and haze properties from Pioneer Venus polarimetry , 1980 .

[4]  S. C. Hill,et al.  Light scattering by size/shape distributions of soil particles and spheroids. , 1984, Applied optics.

[5]  Michael I. Mishchenko,et al.  Erratum: Light scattering by randomly oriented axially symmetric particles [J. Opt. Soc. Am. A 8, 871-882 (1991) , 1992 .

[6]  R. T. Wang,et al.  Scattering from arbitrarily shaped particles: theory and experiment. , 1991, Applied optics.

[7]  M. Mishchenko.  Reflection of polarized light by plane-parallel slabs containing randomly-oriented, nonspherical particles. , 1991 .

[8]  M. Spanner,et al.  Atmospheric correction of remotely sensed image data by a simplified model , 1992 .

[9]  V. G. Farafonov,et al.  Optical properties of spheroidal particles , 1993 .

[10]  Eric P. Shettle,et al.  Atmospheric Aerosols: Global Climatology and Radiative Characteristics , 1991 .

[11]  K. Sassen.  The Polarization Lidar Technique for Cloud Research: A Review and Current Assessment , 1991 .

[12]  N. Khlebtsov,et al.  The linear dichroism and birefringence of colloidal dispersions: Approximate and exact approaches , 1991 .

[13]  J. Penner,et al.  Quantifying and minimizing uncertainty of climate forcing by anthropogenic aerosols , 1994 .

[14]  J. W. Hovenier,et al.  Interpretation of the polarization of Venus , 1974 .

[15]  J. Hansen,et al.  Climate forcing by stratospheric aerosols , 1992 .

[16]  B. Markham,et al.  Aerosol optical properties over the midcontinental United States , 1992 .

[17]  Jean-Louis Roujean,et al.  Analysis of the POLDER (POLarization and directionality of earth's reflectances) airborne instrument observations over land surfaces , 1993 .

[18]  J. Pollack,et al.  Scattering by nonspherical particles of size comparable to wavelength - A new semi-empirical theory and its application to tropospheric aerosols , 1980 .

[19]  W. Wiscombe,et al.  Single scattering from nonspherical Chebyshev particles: a compendium of calculations , 1986 .

[20]  C. E. Siewert,et al.  On the equation of the transfer relevant to the scattering of polarized light , 1981 .

[21]  M. Mishchenko,et al.  Light scattering by size-shape distributions of randomly oriented axially symmetric particles of a size comparable to a wavelength. , 1993, Applied optics.

[22]  Characterization of stratospheric aerosol from polarization measurements , 1988 .

[23]  Pieter Stammes,et al.  Light scattering properties of aerosols and the radiation inside a planetary atmosphere , 1989 .

[24]  M. Mishchenko.  Extinction and Polarization of Transmitted Light by Partially Aligned Nonspherical Grains , 1991 .

[25]  S. Asano,et al.  Light scattering by a spheroidal particle. , 1975, Applied optics.

[26]  S. Asano,et al.  Light scattering by randomly oriented spheroidal particles. , 1980, Applied optics.

[27]  H. Domke.  The expansion of scattering matrices for an isotropic medium in generalized spherical functions , 1974 .

[28]  W. Wiscombe,et al.  Scattering from nonspherical Chebyshev particles. 2: Means of angular scattering patterns. , 1988, Applied optics.

[29]  P. Waterman,et al.  SYMMETRY, UNITARITY, AND GEOMETRY IN ELECTROMAGNETIC SCATTERING. , 1971 .

[30]  Owen B. Toon,et al.  A global average model of atmospheric aerosols for radiative transfer calculations , 1976 .

[31]  Joop W. Hovenier,et al.  Polarized radiation of an atmosphere containing randomly-oriented spheroids. , 1992 .

[32]  A. Mugnai,et al.  Scattering of Radiation by Moderately Nonspherical Particles , 1980 .

[33]  J. Kong,et al.  Theory of microwave remote sensing , 1985 .

[34]  R. A. Chandos,et al.  Galileo Photopolarimeter/Radiometer experiment , 1992 .

[35]  M. Mishchenko.  Extinction of light by randomly-oriented non-spherical grains , 1990 .

[36]  J. Martin,et al.  Galileo Probe Nephelometer Experiment , 1992 .

[37]  K. Liou,et al.  Solar Radiative Transfer in Cirrus Clouds. Part I: Single-Scattering and Optical Properties of Hexagonal Ice Crystals , 1989 .

[38]  Influence of particle shape on the polarized radiation in planetary atmospheres , 1993 .

[39]  H. Gerber.  Absorption of 632.8 nm Radiation by Maritime Aerosols near Europe , 1979 .

[40]  Cornelis V. M. van der Mee,et al.  Fundamental relationships relevant to the transfer of polarized light in a scattering atmosphere , 1983 .

[41]  J. Hovenier,et al.  Benchmark results for single scattering by spheroids , 1992 .

[42]  Z. Kam,et al.  Absorption and Scattering of Light by Small Particles , 1998 .

[43]  J. Hansen,et al.  Light scattering in planetary atmospheres , 1974 .

[44]  B. Draine,et al.  Application of fast-Fourier-transform techniques to the discrete-dipole approximation. , 1991, Optics letters.

[45]  M. Mishchenko.  Light scattering by nonspherical ice grains: An application to noctilucent cloud particles , 1992 .

[46]  V. Vouk.  Projected Area of Convex Bodies , 1948, Nature.

[47]  C. Bohren,et al.  Infrared backscattering by irregularly shaped particles - A statistical approach , 1984 .

[48]  Michael I. Mishchenko,et al.  Light scattering by randomly oriented axially symmetric particles , 1991 .

[49]  O. Glatter,et al.  Mueller matrix calculations for randomly oriented rotationally symmetric objects with low contrast. , 1989, Applied optics.

[50]  W. B. Miller,et al.  Atmospheric propagation and remote sensing 3 , 1994 .

[51]  C. Bohren,et al.  Backscattering by nonspherical particles : a review of methods and suggested new approaches , 1991 .

[52]  W. Wiscombe,et al.  Scattering from nonspherical Chebyshev particles. I: cross sections, single-scattering albedo, asymmetry factor, and backscattered fraction. , 1986, Applied optics.