Toward multiscale simulation of moist flows with soundproof equations

A specific issue involves developing a theoretical basis and practical implementation to include pressure perturbations associated with atmospheric circulations, from small scale to global, into representations of moist thermodynamics. In small-scale modeling using soundproof equations, pressure perturbations are obtained from the elliptic pressure solver and are typically excluded from the moist thermodynamics.

This paper argues that in larger-scale flows, at least the hydrostatic component of the pressure perturbation needs to be included because pressure variation in synoptic weather systems may affect moist thermodynamics in a way comparable to the temperature variations. As an illustration, two idealized test problems are considered: the small-scale moist thermal rising in a stratified environment and the moist mesoscale flow over idealized topography.