The effects of small ice crystals on cirrus infrared radiative properties

Journal Article · Sat Aug 15 04:00:00 EDT 1992 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1992)049<1487:TEOSIC>2.0.CO;2· OSTI ID:5414023

Takano, Y; Liou, K N ^[1]; Minnis, P ^[2]

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1. Univ. of Utah, Salt Lake City, UT (United States)
2. NASA Langley Research Center, Hampton, VA (United States)

Using a model that combines single-scattering properties for spheroidal and hexagonal ice crystals, the thermal infrared radiative properties of cirrus clouds have been investigated. Infrared scattering and absorption properties for randomly oriented spheroids and hexagons are parameterized based on the anomalous diffraction theory and a geometric ray-tracing method, respectively. Using observed ice crystal size distributions, upwelling radiances at the top of cirrus cloudy atmospheres have been computed. Results show that the presence of small ice crystals can produce significant brightness temperature differences between two infrared wavelengths in the 10-[mu]m window. Theoretical results have been compared with observed brightness temperature differences between 8.35 and 11.16 [mu]m and between 11.16 and 12 [mu]m. The observed values were obtained from the High-Spectral Resolution Interferometer Sounder. It is shown that the use of the present nonspherical model for ice crystals in radiative transfer calculations leads to a significantly better interpretation of the observed data than does the use of the spherical model. 12 refs., 6 figs., 1 tab.

• OSTI ID: 5414023
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 49:16; ISSN JAHSAK; ISSN 0022-4928
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
58 GEOSCIENCES
580000 -- Geosciences
CLOUDS
ENERGY TRANSFER
HEAT TRANSFER
ICE
INFRARED SPECTRA
INTERFEROMETRY
METEOROLOGY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIANT HEAT TRANSFER
SPECTRA