Publication Abstracts

Mishchenko et al. 1994

Mishchenko, M.I., A.A. Lacis, and L.D. Travis, 1994: Errors induced by the neglect of polarization in radiance calculations for Rayleigh-scattering atmospheres. J. Quant. Spectrosc. Radiat. Transfer, 51, 491-510, doi:10.1016/0022-4073(94)90149-X.

Although neglecting polarization and replacing the rigourous vector radiative transfer equation by its approximate scalar counterpart has no physical background, it is a widely used simplification when the incident light is unpolarized and only the intensity of the reflected light is to be computed. In this paper we employ accurate vector and scalar multiple-scattering calculations to perform a systematic study of the errors induced by the neglect of polarization in radiance calculations for a homogeneous, plane-parallel Rayleigh-scattering atmosphere (with and without depolarization) above a Lambertian surface. Specifically, we calculate percent errors in the reflected intensity for various directions of light incidence and reflection, optical thicknesses of the atmosphere, single-scattering albedos, depolarization factors, and surface albedos. The numerical data displayed can be used to decide whether or not the scalar approximation may be employed depending on the parameters of the problem. We show that the errors decrease with increasing depolarization factor and/or increasing surface albedo. For conservative or nearly conservative scattering and small surface albedos, the errors are maximum at optical thicknesses of about 1. The calculated errors may be too large for some practical applications and, therefore, rigorous vector calculations should be employed whenever possible. However, if approximate scalar calculations are used, we recommend to avoid geometries involving phase angles equal or close to 0° and 90°, where the errors are especially significant. We propose a theoretical explanation of the large vector/scalar differences in the case of Rayleigh scattering. According to their explanation, the differences are cause by the particular structure of the Rayleigh scattering matrix and come from lower-order (except first-order) light scattering paths involving right scattering angles and right-angle rotations of the scattering plane.

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BibTeX Citation

@article{mi03600a,
  author={Mishchenko, M. I. and Lacis, A. A. and Travis, L. D.},
  title={Errors induced by the neglect of polarization in radiance calculations for Rayleigh-scattering atmospheres},
  year={1994},
  journal={J. Quant. Spectrosc. Radiat. Transfer},
  volume={51},
  pages={491--510},
  doi={10.1016/0022-4073(94)90149-X},
}

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RIS Citation

TY  - JOUR
ID  - mi03600a
AU  - Mishchenko, M. I.
AU  - Lacis, A. A.
AU  - Travis, L. D.
PY  - 1994
TI  - Errors induced by the neglect of polarization in radiance calculations for Rayleigh-scattering atmospheres
JA  - J. Quant. Spectrosc. Radiat. Transfer
VL  - 51
SP  - 491
EP  - 510
DO  - 10.1016/0022-4073(94)90149-X
ER  -

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