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Sky brightness and polarization during the 1973 african eclipse
Applied Optics
|February 6, 2010
Summary
Sky color and polarization changed dramatically during a 1973 solar eclipse. Measurements showed decreased sky radiance and polarization, with spectral shifts toward blue at the zenith and red at the horizon.
Area of Science:
- Atmospheric optics
- Solar eclipses
- Radiative transfer
Background:
- Solar eclipses significantly alter atmospheric conditions.
- Understanding sky radiance and polarization is crucial for atmospheric studies.
Purpose of the Study:
- To measure the absolute intensity, color, and polarization of the sky during the June 30, 1973, solar eclipse.
- To analyze changes in zenith sky radiance, spectral distribution, and polarization ratio.
Main Methods:
- Absolute intensity, color, and polarization measurements of the sky.
- Analysis of zenith sky radiance, spectral distribution, and polarization ratio.
- Comparison of results with radiative transfer models.
Main Results:
- Zenith sky radiance decreased by a factor of 10,000 during totality.
- Sky spectral distribution shifted towards blue at the zenith and reddened at the horizon.
- Polarization ratio decreased significantly from 0.45 to 0.04, influenced by surface albedo.
Conclusions:
- Observed sky changes during the eclipse are consistent with a double-scattering radiative transfer model.
- Surface albedo plays a significant role in the distribution of sky polarization.
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