Abstract

A microphysics model developed by the authors simulates vertical profiles of drop size distribution, relative humidity, temperature, drop concentration, and liquid water content. Drop size distribution profiles simulated by this microphysics model were used with Mie formulations in computing profiles of extinction and backscatter coefficients for several wavelengths. The drops were assumed to be spheres and to exhibit complex indices of refraction defined for two cases: (1) pure water and (2) a combination of pure water and material from condensation nuclei in accordance with a mixture rule. The adequacy of assuming case 1 was tested by comparing results with those calculated for case 2. Extinction and backscatter coefficient profile differences between the two cases were often insignificant (for the wavelengths considered) for engineering applications. This result is significant for computing, since much less computer time is required to compute only one set of Mie efficiency factors per wavelength and then reuse them many times, as can be done when the drops are treated as pure water.

© 1992 Optical Society of America