New abyssal recipes: A revised model of the ocean’s meridional
overturning circulation
Abstract
This work explores the density-driven overturning circulation of the
ocean using a process-oriented three-dimensional hydrodynamic model with
a free sea surface. As expected, dense-water formation in polar regions
creates a deep western boundary current (DWBC) spreading southward ward
along the continental slope. Near the equator, the DWBC releases its
water eastward into the ambient ocean to form a large upwelling zone.
This upwelling is coupled with a slow westward surface recirculation
feeding into a swift surface return flow along the western boundary that
closes the mass budget. This recirculation pattern, which is
fundamentally different to the Stommel-Arons model, is a consequence of
geostrophic adjustment to anomalies of the surface pressure field that
form under the influence of both coastal and equatorial Kelvin waves and
Rossby waves. Based on the findings, the author presents a revised model
of the ocean’s meridional overturning circulation to supersede earlier,
incorrect suggestions.