Early Eocene ocean meridional overturning circulation: The roles of atmospheric forcing and strait geometry

The most common global meridional overturning circulation (MOC) feature of these simulations is the anticlockwise bottom cell, fed by sinking in the Southern Ocean. In the North Pacific, one model (GFDL) displays strong deepwater formation and one model (CESM) shows weak deepwater formation, while in the Atlantic two models show signs of weak intermediate water formation (MIROC and NorESM).

The location of the Southern Ocean deepwater formation sites varies among models and relates to small differences in model geometry of the Southern Ocean gateways. Globally, convection occurs in the basins with smallest local freshwater gain from the atmosphere. The global MOC is insensitive to atmospheric CO2 concentrations from 1x (i.e., 280 ppm) to 3x (840 ppm) pre-industrial levels.