Moist surface frontogenesis associated with interior potential vorticity anomalies in a semigeostrophic model

Abstract

With uniform interior potential vorticity, baroclinic coupling between the upper and surface induced disturbance is weak despite a near neutral moist stability. On the other hand, examples of initial disturbances with interior potential vorticity show greatly enhanced baroclinic coupling between upper and lower disturbances. Comparison with a recent observational study suggests these represent a simple phenomenological description of squall line development. We also find that latent heat release destabilized surface concentrated disturbances which do not intensify in the dry problem. These frontal developments are not primarily baroclinic. Rather, the source of energy is latent heat released in ascent regions and the attendant generation of surface potential vorticity. -from Authors