Parameterization of the optical properties for water clouds in the infrared

A parameterization is presented for the optical properties of water clouds in the infrared spectrum. The cloud optical properties are parameterized in terms of the cloud's liquid water content and the effective radius defined from the droplet size distribution. Rational functions are used for the pa rameterization. The coefficients for the rational functions are derived by doing least square fitting to points calculated by exact Mie theory. The op tical properties are presented for 36 individual wavelengths. Also, paramet erizations in 12 spectral bands between 4 and 1000 mu m are shown. The para meterization is valid for effective radius between 2 and 40 mu m. The accur acy of the parameterization is mostly within 5% compared to the exact Mie c alculations.