The Natural Variability of the Oceanic Thermohaline Circulation (Invited Presentation)

The oceanic thermohaline circulation is forced by horizontally differential heat and water fluxes, primarily those that arise on the planetary scale. Its dynamical behavior exhibits some regimes of great delicacy with respect to the forcing, associated with transitions between multiple equilibria, and others with intrinsic oscillations, due to instabilities of the mean circulation and finite-amplitude limit cycles. Furthermore, its oscillations are easily excited by atmospheric interannual variability, and there is a potentially significant feedback onto the climate associated with anomoalous advection of the upper-ocean temperature in the boundary region between the subtropical and subpolar gyres.