A two-dimensional model of mother-of-pearl clouds

A two-dimensional model of a mother-of-pearl cloud is computed for a specified structure of the atmosphere at the levels of the inversion at about 26 km in the winter polar stratosphere: temperature at the base of the inversion = – 80°C, dewpoint depression = 4C°, wind speed = 50 m/sec and a wave motion with amplitude 660 m and wavelength 40 km. Characteristic features of observed clouds such as the asymmetry and the distribution of particle sizes (observed as distribution of colors) are explained. “Ice wings”, in earlier works incorrectly interpreted as “ice tails”, are explained in the light of three-dimensional mountain waves as ice clouds formed by sublimation when saturation with respect to ice, but not with respect to water, is reached.