Moist Surface Frontogenesis Associated with Interior Potential Vorticity Anomalies in a Semigeostrophic Model

Abstract

Abstract We previously examined surface frontogenesis as an initial value problem in a dry inviscid semigeostrophic Eady model focusing on the frontal dynamics associated with interior potential vorticity anomalies. This work explores frontogenesis associated with potential vorticity anomalies in the presence of latent heat release using a generalization of the two-dimensional) semigeostrophic Eady model that insures that the heating term gives correct asymptotic behavior at high and low temperatures. A variety of initial conditions are considered in which upper-level potential vorticity disturbances induce strong positive potential vorticity anomalies near the lower surface. 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. Comparis...