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

• Published in: Geophysical Research Letters
• Main Authors: Couldrey, MP, Jullion, L, Garabato, AC, Rye, C, Herraiz Borreguero, L, Brown, PJ, Meredith, MP, Speer, KL
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell Publishing, Inc. 2013
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Antarctic; Cape Darnley; Darnley; Indian; Southern Ocean; The Antarctic; Weddell; Antarc*; Antarctica
• Online Access: https://doi.org/10.1002/grl.50526; http://ecite.utas.edu.au/84736

Four repeat hydrographic sections across the eastern Weddell gyre at 30E reveal a warming (by ~0.1C) 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 Currents (ACC) southern boundary in the region. This mechanism of AABW warming may affect wherever the ACC flows close to Antarctica.