On the intensity of the general circulation of the atmosphere

The intensity of the general circulation can be measured by the generation of available potential energy, the conversion of available potential energy to kinetic energy, or the dissipation of kinetic energy by frictional forces. Various estimates of the intensity are reviewed with special emphasis on the assumptions made in each investigation. There is a difference in principle between a nonhydrostatic and a hydrostatic system. In a hydrostatic system the internal and potential energies are proportional to each other, although the potential energy communicates directly with reservoirs of kinetic energy in a nonhydrostatic atmosphere. The review of the concept of available potential energy shows that the approximate form is exact for a quasi‐geostrophic formulation of atmospheric dynamics. A critical evaluation is made of the generation of available potential energy and the dissipation of kinetic energy.