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Updated: Jun 15, 2026
05:10
Measuring the Behavioral Effects of Intraocular Scatter
Published on: February 18, 2021
Summary
A new theory explains halo and rainbow visibility, showing that optically thin clouds create the brightest halos. Rainbow visibility is best in light to moderate rain, not heavy downpours, due to background light effects.
Area of Science:
- Atmospheric optics
- Radiative transfer theory
Background:
- Halos and rainbows are common atmospheric optical phenomena.
- Previous theories did not fully explain visibility variations.
- Light reaching an observer comprises scattered light and background brightness.
Purpose of the Study:
- To present a new theory for halo and rainbow visibility.
- To explain qualitative observations of these phenomena.
- To suggest applications to other atmospheric optics.
Main Methods:
- Developed a theoretical model for light reaching an observer.
- Assumed light consists of singly scattered sunlight/moonlight and background brightness.
- Incorporated light depletion by scattering and absorption.
Main Results:
- Model explains why optically thin cirrostratus clouds produce brightest halos.
- Model accounts for halo visibility depending on sun's elevation due to atmospheric extinction.
- Rainbow brightness peaks for rain optical depth less than or equal to 1, favoring light/moderate showers.
Conclusions:
- The presented theory successfully explains key qualitative observations of halos and rainbows.
- It highlights the role of background brightness and atmospheric extinction.
- The theory provides a framework for understanding other phenomena like coronas and glories.
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