Remotely induced warming of Antarctic Bottom Water in the eastern Weddell gyre

• Published in: Geophysical Research Letters
• Main Authors: Couldrey, Matthew P., Jullion, Loic, Naveira Garabato, Alberto C., Rye, Craig, Herraiz-Borreguero, Laura, Brown, Peter J., Meredith, Michael P., Speer, Kevin L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Antarctic; Southern Ocean; The Antarctic; Indian; Weddell; Darnley; Cape Darnley; Antarc*; Antarctica
• Online Access: http://nora.nerc.ac.uk/id/eprint/500831/; https://nora.nerc.ac.uk/id/eprint/500831/1/grl50526.pdf

Four repeat hydrographic sections across the eastern Weddell gyre at 30°E reveal a warming (by ~0.1°C) and lightening (by ~0.02–0.03 kg m−3) of the Antarctic Bottom Water (AABW) entering the gyre from the Indian sector of the Southern Ocean between the mid-1990s and late 2000s. Historical hydrographic and altimetric measurements in the region suggest that the most likely explanation for the change is increased entrainment of warmer mid-depth Circumpolar Deep Water by cascading shelf water plumes close to Cape Darnley, where the Indian-sourced AABW entering the Weddell gyre from the east is ventilated. This change in entrainment is associated with a concurrent southward shift of the Antarctic Circumpolar Current's (ACC) southern boundary in the region. This mechanism of AABW warming may affect wherever the ACC flows close to Antarctica.