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Updated: Jun 17, 2026
11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Near infrared scattering by sunlit terrestrial clouds.
H H Blau1, R P Espinola, E C Reifenstein
1Arthur D. Little, Inc., Cambridge, Massachusetts 02140, USA.
Applied Optics
|January 6, 2010
Summary
Cloud scattering spectra reveal differences between ice and liquid water clouds in the 1.15- to 3.6-micrometer range. Particle size significantly impacts scattering efficiency and spectral features, aligning with theoretical predictions.
Area of Science:
- Atmospheric optics
- Cloud physics
- Spectroscopy
Background:
- Solar radiation scattering by clouds is crucial for Earth's energy balance.
- Understanding cloud optical properties requires detailed spectral analysis.
- Previous studies lacked comprehensive data across various cloud types and scattering angles.
Purpose of the Study:
- To measure absolute intensity spectra of solar radiation scattered by clouds.
- To investigate the angular dependence of cloud scattering across different wavelengths.
- To differentiate scattering characteristics of ice and liquid water clouds.
Main Methods:
- Acquisition of radiance spectra in the 1.15- to 3.6-micrometer region.
- Measurements as a function of cloud type, altitude, and scattering angle.
- Analysis of spectral features and scattering efficiency.
Main Results:
- Scattering efficiency increased significantly with decreasing scattering angle, particularly in strongly absorbing regions (2.6-2.9 µm).
- Ice clouds exhibited characteristic spectral minima at 1.5, 2.0, and 2.8 µm due to absorption.
- These minima were absent in liquid-water clouds, despite similar bulk absorption properties.
Conclusions:
- Particle size is a key factor explaining the observed differences in scattering behavior between ice and liquid water clouds.
- The findings align with theoretical models of light scattering.
- Spectral analysis provides valuable insights into cloud microphysical properties.
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