Abstract

Absolute intensity (radiance) spectra of solar radiation scattered by clouds were obtained in the 1.15-μ to 3.6-μ region as a function of cloud type, cloud altitude, and scattering angle. The angular dependence of cloud scattering was determined at a number of wavelengths between 1.15 μ and 3.6 μ From 2.6 μ to 2.9 μ, where water and ice are strongly absorbing and single scattering dominates, scattering efficiency increases nearly tenfold as the scattering angle decreases from 150° to 45°, in agreement with theory. At shorter and longer wavelengths, scattering efficiency increases by about a factor of three over the same range of scattering angles. Characteristic minima are observed in spectra of ice clouds at 1.5 μ, 2.0 μ, and 2.8 μ, which are related to absorptions in the bulk material at the same wavelengths. The 1.5-μ and 2.0-μ minima are absent in spectra of liquid-water clouds, even though the absorption characteristics of bulk water and ice are very similar. The differences in scattering behavior are explained on the basis of particle size.

© 1966 Optical Society of America

Cloud Structure from Infrared Imagery

Henry H. Blau
Appl. Opt. 7(10) 1903-1905 (1968)

The Scattering of Infrared Radiation from Clouds

Ernest Bauer
Appl. Opt. 3(2) 197-202 (1964)

Radiative Transfer in Water and Ice Clouds in the Visible and Infrared Region

G. N. Plass and G. W. Kattawar
Appl. Opt. 10(4) 738-748 (1971)

Near Infrared Reflection Spectra of Artificial Cumulus Clouds

W. T. Plummer
Appl. Opt. 8(10) 2079-2081 (1969)

Spectral Properties of Clouds from 2.5 μ to 3.5 μ

Henry H. Blau and Ronald P. Espinola
Appl. Opt. 7(10) 1897-1901 (1968)