Numerical evaluation of moist available energy

Abstract

A numerical procedure for evaluating moist available energy (MAE), given the pressure, temperature, and relative humidity of a representative set of atmospheric “parcels”, is presented. The procedure determines a reference field by rearranging the parcels while preserving the mass and entropy of each parcel, and subsequently subtracts the enthalpy of the reference field from that of the given field to obtain the MAE.

Computations using the procedure agree reasonably well with the results of a previously formulated graphical procedure. They confirm a finding of Wojcik (1977) that a small temperature increase, with no change in relative humidity, will produce a large increase in MAE.