Available potential energy and simplifications to the adiabatic equation

In this paper the known property of the “quasi-geostrophic” form of the adiabatic equation to conserve rather than convert mean total potential energy (TPE) or available potential energy (APE) is analysed by tracing the contributions to the conversion to kinetic energy (KE), made by individual terms of the adiabatic equation. The approach and notation of a previous paper (Burger and Riphagen, 1979, hereafter referred to as BR1) are used, and that paper" final example is amplified. Application of the same approach to the Lorenz (1955) form of APE then demonstrates the analytical mechanism which enables an acceptable energy behaviour to be obtained in this context.