Representing Moisture Processes in Mesoscale Numerical Models

Abstract

Moisture variables and associated physics are necessary in mesoscale models to properly predict virtual temperature, moisture distributions, cloud formation, precipitation formation and fallout, latent heating associated with phase changes of water, and surface fluxes of heat and moisture. Without properly simulating, for example, the diabatic heating associated with phase changes of water substance and surface fluxes of water vapor, we would not be able to accurately predict the formation and intensification of many mesoscale circulations, as well as both smaller- and larger-scale circulations. Moreover, the inclusion of moisture in mesoscale numerical models facilitates a more accurate foundation for describing the radiation balance of the atmosphere and permits cloud and precipitation forecasts.