South Orkney Plateau: Determining how shifts in the south westerly winds impacts the exchange of waters between the Antarctic Circumpolar Current and the Weddell Gyre

Dense deep and bottom waters exported from beneath the sea ice and ice shelves of the Weddell Sea form a critical component of the Atlantic meridional circulation, regulating global ocean circulation. Recent observations reveal that waters exported from the Weddell Sea into the Scotia Sea are becoming significantly warmer and fresher. The concurrent poleward shift of the southern westerly winds (SWW) could explain this trend, in which case the predicted continuation of this SWW migration through the 21st century would likely intensify upper ocean overturning and reduce sea ice, in turn leading to continued warming and freshening of waters exported from the WS. These changes would have a profound impact on the local ecosystem as well as implications for global ocean circulation.
While climate reconstructions in the West Antarctic Peninsula, Subantarctic Islands and South America have shown that the SWW belt migrated south (north) of its current trajectory during the Early (Late) Holocene, with significant impacts on regional oceanography, the effect that these SWW migrations may have had on the Weddell Sea region and deep/bottom water formation has not yet been investigated.
The South Orkney Plateau (SOP) in the SW Atlantic straddles the South Scotia Ridge between the Scotia and Weddell Seas. Waters entrained within the Weddell Sea gyre are exposed to sub-ice shelf and sea ice processes, increasing their density causing them to sink as deep/bottom waters. Export of these dense waters into the Scotia Sea, while en route north into the Atlantic, allows a degree of mixing with the relatively warm Circumpolar Deep Water (CDW) in the Antarctic Circumpolar Current (ACC). It is now well established that poleward shifts in the SWW increase upwelling of CDW along the southern boundary of the ACC. Similarly, sea-ice, ocean temperatures and water mass composition along the northern limb of the Weddell Sea gyre are likely to be sensitive to shifts in the SWW. Located along the boundary between the ACC and the Weddell Sea gyre, the SOP is ideally placed to establish how changes in the position of the SWW impact ocean circulation in this region.
Using diatoms and foraminferal proxies (assemblages and stable isotopes) to reconstruct sea-ice cover, surface & deep ocean temperatures, productivity, water mass distribution and stratification in the SOP region will provide the necessary information to determine how the boundary between the ACC and Weddell Sea gyre, and also deep/bottom water export responds to changes in the position of the SWW.
http://nercgw4plus.ac.uk/project/south-orkney-plateau-determining-how-shifts-in-the-south-westerly-winds-impacts-the-exchange-of-waters-between-the-antarctic-circumpolar-current-and-the-weddell-gyre-2/