Size distribution models of fog and cloud droplets in terms of the modified gamma function

Abstract

Size spectra of water droplets in haze, fogs and clouds of various type measured by several authors have been analyzed by a computational method in terms of the modified gamma distribution function. The preliminary results are shown on the wide ranges that result of the function parameters. These results are synthesized using a graphical method to obtain average and representative size distribution models suitable for reproducing size spectra of water droplets typical for fog and clouds in different evolutionary stages. The examination of the results in terms of skewness and kurtosis suggests typical behaviours of these two shape-parameters which can be taken into account in obtaining multimodal size distributions by the use of the properly weighted models found. The analytical expressions of skewness and kurtosis in the modified gamma distribution function are given in the Appendix. DOI: 10.1111/j.2153-3490.1976.tb00682.x