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Publication Date
16 April 2022

Baroclinic Control of Southern Ocean Eddy Upwelling Near Topography

Examining how much and why topography impacts cross-jet transport, and how to improve the representation of these processes in models.
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Southward transport across the jet axis, as explicitly resolved by the high-resolution model (abscissa), and as estimated by three different parameterizations (ordinate). Upper row is for a seamount of 150 m, the lower row for 300 m. Note that the parameterization in the right-most column is the best match to the resolved transport. This parameterization is based on a quantity that measures how fast eddies grow through one specific mechanism (baroclinic instability), rather than how strong they are.

We use an idealized model of an ocean jet to examine how bottom topography along the Antarctic Circumpolar Current can enhance and localize eddy-induced upwelling. We find that the upwelling systematically occurs in regions where eddies grow through baroclinic instability, rather than in regions where eddy energy is large. We propose a simple parameterization of eddy-induced upwelling based on the zonal evolution of eddy energy, which provides a better representation of the zonal variability of upwelling around topography compared with existing parameterizations.


The upwelling that occurs in the Southern Ocean is an essential part of the global heat and carbon cycle, and ocean models rely on eddy parameterizations to represent these. Future ocean eddy parameterizations should consider metrics specific to the growth of baroclinic instability to accurately model eddy upwelling near topography.


The Southern Ocean plays an essential role in redistributing heat, salt, and biogeochemical tracers of importance in the climate system. In particular, locations in which strong ocean currents interact with large topographic features are hotspots for eddy-driven upward transport and are crucial pathways to bring deep, carbon- and nutrient-rich waters to the surface. The processes that set the location and magnitude of this eddy “upwelling” remain challenging to understand. This study uses a series of high-resolution idealized simulations in which an ocean jet encounters a piece of topography to investigate what controls the eddy upwelling near topography. We find that the upwelling due to eddies occurs in regions where the eddies are growing through a mechanism called “baroclinic instability,” rather than in regions where eddies are highly energetic or energized by other mechanisms. Regions of growing eddy energy are a simple, first-order indicator of regions of eddy upwelling, but future parameterizations of transport should consider the mechanism of instability to be more accurate.

Point of Contact
Alice Barthel
Los Alamos National Laboratory (LANL)
Funding Program Area(s)