Linearized problem relative to a basic state with velocity shear and tilted density surfaces

We retain the basic set of equations (4.4) to (4.6) for an inviscid, non-diffusive fluid but allow a more general basic state in quasi-static and quasi-geostrophic equilibrium (as in a large scale circulation regime). We assume that the basic state properties are such that:

• Perturbation equations
• Associated perturbation energy equation