Diagnostic studies of a two-dimensional simulation of frontogenesis in a moist atmosphere.

The two-dimensional model simulation of frontogenesis in a moist atmosphere discussed by Hsie and others is used to provide dynamically consistent data for diagnostic calculations to quantify the physical processes important in the frontogenesis. The terms in the prognostic equations for the horizontal gradient of potential vorticity, relative vorticity, and static stability are evaluated to indicate the relative importance of confluence, shear, tilting, and frictional and diabatic processes in generating these properties of the front. An evaluation of the potential vorticity and equivalent potential vorticity fields and their budgets indicates that symmetric instability is not present in the dry simulation, but occurs in the moist simulation and is associated with the formation of rainbands. -from Authors