Development of a moisture scheme for the explicit numerical simulation of moist convection

Abstract

The Council for Scientific and Industrial Research is developing a nonhydrostatic sigma coordinate model (NSM). This model will be used to simulate nonhydrostatic processes to help meteorologists better understand and forecast convective processes. The aim of this study is to add a moisture scheme to the NSM. As a first step a simple model that is equivalent to the first pressure-coordinate nonhydrostatic model used to simulate cumulonimbus clouds in 1974 is developed. The equation set that includes 3 water particles, cloud water, water vapour and rain water has been derived.The equation set will be coded and tested using theoretical studies. The model will be extended to represent the real atmosphere and will include 8 different types of water particles usually used in bulk models and tested using theoretical studies and later the real atmosphere.