Publication Abstracts

Hansen and Matsushima 1966

Hansen, J.E., and S. Matsushima, 1966: Light illuminance and color in the Earth's shadow. J. Geophys. Res., 71, 1073-1081, doi:10.1029/JZ071i004p01073.

The illuminance in the earth's shadow at three wavelengths is computed by performing a double numerical integration over the atmosphere. As sources of light attenuation, one absorption and extinction by dust and clouds are taken into account in addition to the usual Rayleigh scattering and the beam divergence due to refraction. Light inserted into the shadow through scattering by molecules and aerosol particles is also included in the calculations. The solar limb darkening is accounted for. Special emphasis is placed on finding an explanation for the unusual eclipse of December 30, 1003, in which an extremely low illuminance and nonreddening were observed. Calculations are carried out for various models of the earth's atmosphere, and it is shown that the dust particles may account for large changes in the illuminance from eclipse to eclipse. The dust and clouds appear to cause the nonreddening by enhancing the importance of the diffused light in the central region of the earth's shadow. The observation of the 1963 eclipse is explained by assuming aa abnormally large extinction prcsumably caused by dust sprcad by the eruption of Mount Agung on March 17, 1963. The requircd additional extinction amounts to about 14% of the incident light per air mass in the visible region, which agrees with direct measurements of the photometric extinction made at various observatories during the ycar 1963. The theory also provides a conclusive means of distinguishing between extinction due to dust particles and that due to clouds. An approximate value for the amount of ozone in the atmosphere can be determined. The results suggest uscful photometric obscrvations of future eclipses.

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BibTeX Citation

@article{ha08210q,
  author={Hansen, J. E. and Matsushima, S.},
  title={Light illuminance and color in the Earth's shadow},
  year={1966},
  journal={J. Geophys. Res.},
  volume={71},
  pages={1073--1081},
  doi={10.1029/JZ071i004p01073},
}

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RIS Citation

TY  - JOUR
ID  - ha08210q
AU  - Hansen, J. E.
AU  - Matsushima, S.
PY  - 1966
TI  - Light illuminance and color in the Earth's shadow
JA  - J. Geophys. Res.
VL  - 71
SP  - 1073
EP  - 1081
DO  - 10.1029/JZ071i004p01073
ER  -

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