Early Eocene Ocean Meridional Overturning Circulation: The Roles of Atmospheric Forcing and Strait Geometry

Here, we compare the ocean overturning circulation of early Eocene (47–56 Ma) in eight coupled climate model simulations from Deep-Time Model Intercomparison Project (DeepMIP) and investigate causes observed inter-model spread. The most common global meridional (MOC) feature these is anticlockwise bottom cell, fed by sinking Southern Ocean. In North Pacific, one (GFDL) displays strong deepwater formation (CESM) shows weak formation, while Atlantic two models show signs intermediate water (MIROC NorESM). location Ocean sites varies among relates to small differences geometry gateways. Globally, convection occurs basins with smallest local freshwater gain atmosphere. MOC insensitive atmospheric CO2 concentrations 1× (i.e., 280 ppm) 3× (840 pre-industrial levels. Only have higher CESM GFDL) divergent responses, a collapsed active MOC, respectively, possibly due spin-up conditions. Combining multiple results available proxy data on abyssal highlights that Hemisphere-driven likely Eocene. Atlantic, unlike present day, neither nor suggest open during Eocene, evidence for Pacific remains inconclusive.