Entropy versus APE production: On the buoyancy power input in the oceans energy cycle

Abstract

This letter argues that the current controversy about whether W buoyancy, the power input due to the surface buoyancy fluxes, is large or small in the oceans stems from two distinct and incompatible views on how W buoyancy relates to the volume-integrated work of expansion/contraction B. The current prevailing view is that W buoyancy should be identified with the net value of B, which current theories estimate to be small. The alternative view, defended here, is that only the positive part of B, i.e., the one converting internal energy into mechanical energy, should enter the definition of W buoyancy, since the negative part of B is associated with the non-viscous dissipation of mechanical energy. Two indirect methods suggest that by contrast, the positive part of B is potentially large. © 2010 by the American Geophysical Union.