Exergetics of Deep Moist Convection

Exergetics is a formal thermodynamical approach to defining energy components as quadratic quantities that are always positive definite. This nonlinear approach is based on a finite difference representation of the Gibbs thermodynamic relation. Here the exergetics of moist processes is presented using the Gibbs relation in terms of the entropy, enthalpy, pressure, and water mixing ratio. The total exergy is the sum of the kinetic energy and the static exergy. The static exergy is divided into two components: available potential exergy and available elastic exergy. These quantities reduce to the traditional available potential energy and available elastic energy of linear dry compressible theory. The conversion processes among the kinetic energy and static exergy components are delineated. Both Lagrangian and Eulerian formulations are developed. Available energy, availability, and entropic energy are other appellations of exergy. The theory of moist exergy will be applied to the problem of deep moist convection. Comparison of the exergy approach will be made with the traditional energy approach involving kinetic, potential, and internal energy.