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We extend exploration of potential vorticity instabilities in coldastrophysical disks whose mean states are baroclinic. In particular, we seek todemonstrate the potential existence of traditional baroclinic instabilities ofmeteorological studies in a simplified two-layer Philips Disk Model. Each disklayer is of constant but differing densities. The resulting mean azimuthalvelocity profile shows a variation in the vertical direction implying that thesystem is baroclinic in the mean state. The stability of the system is treatedin the context of disk shallow water theory wherein azimuthal disturbances aremuch longer than the corresponding radial or vertical scales. The normal-modeproblem is solved numerically using two different methods. The results of asymmetric single layer barotropic model is considered and it is found thatinstability persists for models in which the potential vorticity profiles arenot symmetric, consistent with previous results. The instaiblity is interpretedin terms of interacting Rossby waves. For a two layer system in which the flowis fundamentally baroclinic we report here that instability takes on the formof mixed barotropic-baroclinic type: instability occurs but it qualitativelyfollows the pattern of instability found in the barotropic models. Instabilityarises because of the phase locking and interaction of the Rossby waves betweenthe two layers. The strength of the instability weakens as the density contrastbetween layers increases. (For full abstract see article.)

Potential vorticity dynamics in the framework of disk shallow-water theory: II. Mixed Barotropic-Baroclinic Instability