The Southern Ocean stretching from the partly ice-covered continental shelves to the northern fringe of the Antarctic Circumpolar Current is a key region for water mass formation and the vertical and lateral exchange of heat, carbon and nutrients. Understanding and quantifying its role as a large sink of heat and anthropogenic carbon, as a driver of ice-shelf melt, and as part of the global overturning circulation is associated with great uncertainties. To reduce these uncertainties, understanding the physical and biogeochemical processes underlying Southern Ocean internal variability, its interaction with ice-shelves, icebergs, and sea ice, and its response to external forcing is crucial. Recent advances in observational capabilities, such as autonomous floats, gliders, and satellite systems, as well as numerical models at unprecedented resolution and complexity, are providing a deeper insight into the three-dimensional patterns of Southern Ocean processes and their sensitivity to climate change. This session will discuss the current state of knowledge and novel findings concerning the role of the Southern Ocean in past, present and future climates, including its mixing and mesoscale processes, water mass formation, ice-ocean and ocean-topography interactions, biogeochemical cycling, pathways of upwelling and subduction, water mass exchanges with lower latitudes, and ocean-atmosphere interactions.

Fridtjof Nansen Medal Lecture by
Lynne Talley: "The changing climate of the Southern Ocean: influence of the meandering pathway of the Antarctic Circumpolar Current"

Solicited speakers:

Nicole Lovenduski (University of Colorado Boulder, US) on the uncertainty in projections of Southern Ocean carbon uptake and acidification

Elin Darelius (University of Bergen, Norway) on current research in the Filchner Trough area, a key region of ice-ocean interaction and ongoing change.