Physical sciences

Circular polarization of twilight

J Roger P Angel, R. Illing, P. G. Martin

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

LINEAR polarization of clear daytime sky and twilight is produced by molecular (Rayleigh) scattering and aerosol (Mie) scattering, which predominates in the infrared. Incident linearly polarized light scattered by aerosols is in general elliptically polarized, whereas no ellipticity can arise from the molecular component1. The principal component of clear daytime sky arises from single scattering of unpolarized sunlight and is not elliptically polarized. However, whenever multiple scattering by the aerosol component is important, the strong linear polarization produced on the first scattering will lead to elliptical polarization from the second and subsequent scatterings. Although in the daytime sky this mechanism should give only a small ellipticity2 (10-5-10-3) the possibility of a substantially larger effect at twilight arises because there is no direct illumination. We report here observations of circular polarization of twilight of order 10-3.

Original languageEnglish (US)
Pages (from-to)389-390
Number of pages2
JournalNature
Volume238
Issue number5364
DOIs
StatePublished - 1972
Externally publishedYes

Fingerprint

physical sciences
circular polarization
daytime
sky
aerosols
scattering
elliptical polarization
Mie scattering
ellipticity
Rayleigh scattering
sunlight
linear polarization
polarized light
illumination
polarization

ASJC Scopus subject areas

  • General

Cite this

Physical sciences : Circular polarization of twilight. / Angel, J Roger P; Illing, R.; Martin, P. G.

In: Nature, Vol. 238, No. 5364, 1972, p. 389-390.

Research output: Contribution to journalArticle

Angel, JRP, Illing, R & Martin, PG 1972, 'Physical sciences: Circular polarization of twilight', Nature, vol. 238, no. 5364, pp. 389-390. https://doi.org/10.1038/238389a0
Angel, J Roger P ; Illing, R. ; Martin, P. G. / Physical sciences : Circular polarization of twilight. In: Nature. 1972 ; Vol. 238, No. 5364. pp. 389-390.
@article{55bb5f1139c7435e9dccc1e7303f2d55,
title = "Physical sciences: Circular polarization of twilight",
abstract = "LINEAR polarization of clear daytime sky and twilight is produced by molecular (Rayleigh) scattering and aerosol (Mie) scattering, which predominates in the infrared. Incident linearly polarized light scattered by aerosols is in general elliptically polarized, whereas no ellipticity can arise from the molecular component1. The principal component of clear daytime sky arises from single scattering of unpolarized sunlight and is not elliptically polarized. However, whenever multiple scattering by the aerosol component is important, the strong linear polarization produced on the first scattering will lead to elliptical polarization from the second and subsequent scatterings. Although in the daytime sky this mechanism should give only a small ellipticity2 (10-5-10-3) the possibility of a substantially larger effect at twilight arises because there is no direct illumination. We report here observations of circular polarization of twilight of order 10-3.",
author = "Angel, {J Roger P} and R. Illing and Martin, {P. G.}",
year = "1972",
doi = "10.1038/238389a0",
language = "English (US)",
volume = "238",
pages = "389--390",
journal = "Nature",
issn = "0028-0836",
publisher = "Nature Publishing Group",
number = "5364",

}

TY - JOUR

T1 - Physical sciences

T2 - Circular polarization of twilight

AU - Angel, J Roger P

AU - Illing, R.

AU - Martin, P. G.

PY - 1972

Y1 - 1972

N2 - LINEAR polarization of clear daytime sky and twilight is produced by molecular (Rayleigh) scattering and aerosol (Mie) scattering, which predominates in the infrared. Incident linearly polarized light scattered by aerosols is in general elliptically polarized, whereas no ellipticity can arise from the molecular component1. The principal component of clear daytime sky arises from single scattering of unpolarized sunlight and is not elliptically polarized. However, whenever multiple scattering by the aerosol component is important, the strong linear polarization produced on the first scattering will lead to elliptical polarization from the second and subsequent scatterings. Although in the daytime sky this mechanism should give only a small ellipticity2 (10-5-10-3) the possibility of a substantially larger effect at twilight arises because there is no direct illumination. We report here observations of circular polarization of twilight of order 10-3.

AB - LINEAR polarization of clear daytime sky and twilight is produced by molecular (Rayleigh) scattering and aerosol (Mie) scattering, which predominates in the infrared. Incident linearly polarized light scattered by aerosols is in general elliptically polarized, whereas no ellipticity can arise from the molecular component1. The principal component of clear daytime sky arises from single scattering of unpolarized sunlight and is not elliptically polarized. However, whenever multiple scattering by the aerosol component is important, the strong linear polarization produced on the first scattering will lead to elliptical polarization from the second and subsequent scatterings. Although in the daytime sky this mechanism should give only a small ellipticity2 (10-5-10-3) the possibility of a substantially larger effect at twilight arises because there is no direct illumination. We report here observations of circular polarization of twilight of order 10-3.

UR - http://www.scopus.com/inward/record.url?scp=8044233892&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=8044233892&partnerID=8YFLogxK

U2 - 10.1038/238389a0

DO - 10.1038/238389a0

M3 - Article

VL - 238

SP - 389

EP - 390

JO - Nature

JF - Nature

SN - 0028-0836

IS - 5364

ER -