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Updated: Jun 13, 2026
06:50
Enabling High Grayscale Resolution Displays and Accurate Response Time Measurements on Conventional Computers
Published on: February 29, 2012
Summary
This study presents a new theory on rainbow brightness, explaining why lower rainbow portions appear brighter and redder. This phenomenon is due to atmospheric light scattering and absorption affecting sunlight reaching the observer.
Area of Science:
- Atmospheric optics
- Radiative transfer theory
Background:
- Rainbows are optical phenomena caused by light interacting with water droplets.
- Previous models did not fully explain variations in rainbow brightness and color intensity.
Purpose of the Study:
- To develop a comprehensive theory for rainbow brightness.
- To explain the observed brightness and color gradients within a rainbow, particularly near the horizon.
Main Methods:
- A theoretical model was developed incorporating cloud geometry and solar position.
- The model accounts for singly scattered sunlight and atmospheric depletion effects (scattering and absorption).
Main Results:
- The model explains why the lower portion of a rainbow is brighter and redder than the upper portion when the sun is near the horizon.
- Greater brightness at the bottom is linked to the longer illuminated rainswath near the horizon.
- Increased redness at the bottom is attributed to the depletion of short-wavelength light during atmospheric passage.
Conclusions:
- The presented theory accurately models rainbow brightness and color variations.
- Atmospheric depletion significantly influences the spectral composition and intensity of light forming rainbows.
- The model provides a framework for understanding complex light-scattering phenomena in the atmosphere.
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