Thermodynamics of Cloud Glaciation

Abstract

A detailed thermodynamical analysis of the glaciation of a supercooled cloud parcel has been carried out, applying a linear approximation to the vapor pressure curves for ice and water. The process can lead to three different final states: one in which partial glaciation of the supercooled cloud water brings the parcel temperature to 0C, one in which sublimation of water vapor takes place from the frozen phase, and one in which deposition occurs to it. It is pointed out that a treatment which considers only the release of latent heat of fusion, without taking into account the subsequent change in water vapor density, is a special, case and is generally incorrect.