What did we do? We analyzed the observational data and an eddy-resolving ocean circulation model to investigate what controls the density stratification of the Southern Ocean.
What did we find? Both observed and simulated slope of density surfaces approximately follows the principle of baroclinic neutrality in the quasi-geostrophic approximation, where the changing slope of density surfaces roughly balances the beta-effect (the effect derived from the rotating spherical planet).
Why is it important? We cannot emphasize enough the importance of ocean stratification in regulating ocean currents, climate and biogeochemical cycling. This study demonstrate how the slope of density surfaces in the Southern Ocean is controlled by the turbulent eddies mixing of potential vorticity. The take-home message is: we need to understand the role of eddies in the Southern Ocean circulation and biogeochemistry.
Reference: Jones, D., T. Ito, T. Birner, A. Klocker and D. Munday, (2015), Planetary-geometric constraints on isopycnal slope in the Southern Ocean, Journal of Physical Oceanography, doi:10.1175/JPO-D-15-0034.1