30 December 1981 Review Of Cirrus Cloud Optical Properties And Effects On Infrared Sensors
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Cirrus cloud optical properties are largely unknown because of the var-iety of ice crystal shapes frequently occurring in these clouds, which make Mie calculations difficult. In addition, the index properties of the ice surface are functions of temperature as well as wavelength. Because of the large size of the particles in cirrus, scattering is even more predominantly in the forward direction than in liquid water clouds. Consequently, cirrus appear more transparent than is the fact and are seriously under reported. The distribution of cirrus optical thickness is strongly skewed to small values. Unreported thin,(τ∠1) cirrus may occur over as much as twice as much area or time as does reported cirrus. An average (and marginally reported) cirrus cloud might have a beam transmission of 0.5, diffuse transmission of 0.8 and emissivity of 0.2 at 10 μm. Currently measurements of cirrus are being conducted at Boulder and Maui. This paper reviews past and current measurements of cirrus properties and presents simple models relating these properties.
© (1981) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John D. Malick "Review Of Cirrus Cloud Optical Properties And Effects On Infrared Sensors", Proc. SPIE 0305, Atmospheric Effects on Electro-Optical, Infrared, and Millimeter Wave Systems Performance, (30 December 1981); doi: 10.1117/12.932699; https://doi.org/10.1117/12.932699

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