The vertical resistribution of momentum by the pressure-based EP flux and its energetics over the global ocean currents

A set of every-3-day snapshots from a high-resolution (0.1 x 0.1 deg) global OGCM is analyzed in the present study by using a low-pass temporal filter in density-coordinates, in order to demonstrate the self-consistency of the adiabatic mean four-box energy diagram and associated energy cycle derived recently. We show the global distribution of energy conversion done by the residual effects of pressure perturbations (the pressure-based EP flux or the eddy form stress), which is an energy cascade to the perturbation field whose rate is as intense as the works of the eddy-induced overturning circulations and the wind-induced Ekman transports in the world's oceans. A work associated with the vertical redistribution of momentum by the eddy form stress is one order larger than that associated with the horizontal redistribution of momentum. The eddy form stress and the eddy-induced velocity are shown to be in near geostrophic balance, resulting in the adiabatic aspects of oceanic dynamics in mid and high latitudes being explained by a set of planetary geostrophic equations. We point out that the vertical redistribution of momentum by the eddy form stress cancels (and reduces) the vertical shear resulting from the eddy-induced overturning circulation (rather than the vertical shear resulting from the surface wind stress).