How does Antarctic Bottom Water Cross the Southern Ocean?

• Main Authors: Solodoch, A., Stewart, A. L., Hogg, A. McC., Morrison, A. K., Kiss, A. E., Thompson, A. F., Purkey, S. G., Cimoli, L.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2022
• Subjects: Meridional Overturning Circulation; Antarctic Bottom Water; Ocean circulation; Southern Ocean; Deep Western Boundary Currents; Ocean Stirring; General Earth and Planetary Sciences; Geophysics; Antarctic; Indian; Kerguelen; Pacific; Prydz Bay; Ross Sea; Weddell; Weddell Sea; Adelie Land; Antarc*; Sea ice
• Online Access: https://doi.org/10.1029/2021gl097211

Antarctic Bottom Water (AABW), which fills the global ocean abyss, is derived from dense water that forms in several distinct Antarctic shelf regions. Previous modeling studies have reached conflicting conclusions regarding export pathways of AABW across the Southern Ocean and the degree to which AABW originating from distinct source regions are blended during their export. This study addresses these questions using passive tracer deployments in a 61-year global high-resolution (0.1°) ocean/sea-ice simulation. Two distinct export "conduits" are identified: Weddell Sea- and Prydz Bay-sourced AABW are blended together and exported mainly to the Atlantic and Indian Oceans, while Ross Sea- and Adelie Land-sourced AABW are exported mainly to the Pacific Ocean. Northward transport of each tracer occurs almost exclusively (>90%) within a single conduit. These findings imply that regional changes in AABW production may impact the three-dimensional structure of the global overturning circulation. © 2022 American Geophysical Union. Issue Online: 09 April 2022; Version of Record online: 09 April 2022; Accepted manuscript online: 24 March 2022; Manuscript accepted: 22 March 2022; Manuscript revised: 22 February 2022; Manuscript received: 30 November 2021. We thank two anonymous reviewers, which have provided helpful feedback and advice. We also kindly thank Fukamachi Yasushi, of the Institute of Low Temperature Science, Hokkaido University, for sharing their observational data of velocity and temperature at the Kerguelen Plateau (Fukamachi et al., 2010) (compared with model data in Text S6 of the Supporting Information S1). This work depended on the COSIMA consortium (www.cosima.org.au) which provides the ACCESS-OM2 suite of models. The numerical simulations and analyses were performed with the resources of the National Computational Infrastructure (Canberra, Australia), which is supported by the Australian Government. AS and ALS were partially supported by the National Science Foundation (NSF) under Grant Nos. ...