Trends in the global available energy in reanalysis data

The available energy of the atmosphere is the theoretical maximum amount of the total potential energy (i.e., the sum of the internal and gravitational energy) that can be converted into kinetic energy. It includes contributions from baroclinic available potential energy as well as convective available potential energy. We define a reference atmosphere which is isothermal and hydrostatic. The minimization of an energy availability function between this reference and the actual atmosphere determines the equilibrium temperature of the reference atmosphere and the available energy. This approach is general and includes the effects due to water vapor, hydrometeors, and terrain. Using reanalysis data, we calculate the available energy due to each component (i.e., dry air, water vapor, hydrometeors) of the atmosphere at every grid point. Thus, we are able to calculate a value of the available energy locally and globally. Preliminary results for the ECMWF reanalysis suggests that the equilibrium temperature of the atmosphere and its available energy have been increasing from 1979-2012. Regionally we detect an increase in available energy over the western tropical Pacific Ocean and a decrease over the central/eastern Pacific. This structure suggests a strengthening of the Walker circulation.