Published April 16, 2022 | Published + Accepted Version + Supplemental Material
Journal Article Open

How does Antarctic Bottom Water Cross the Southern Ocean?

Abstract

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.

Additional Information

© 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. OPP-2023244, and by the National Aeronautics and Space Administration ROSES Physical Oceanography program under Grant No. 80NSSC19K1192. AKM was supported by the Australian Research Council (ARC) DECRA Fellowship DE170100184. AEK was funded by ARC grant LP160100073 and the Australian Government's Australian Antarctic Science Grant Program. AFT was partially supported by NSF grant OCE-2023259. Data Availability Statement: The model source code is available from https://github.com/COSIMA/access-om2 and model configuration files are available from https://github.com/COSIMA/01deg_jra55_iaf/tree/01deg_jra55v140_iaf_cycle3. Output data is publicly available from http://dx.doi.org/10.25914/608097cb3433f. Reprocessed altimetric sea surface height data (SEALEVEL_GLO_PHY_L4_REP_OBSERVATIONS_008_047) distributed by Copernicus Marine Service (https://resources.marine.copernicus.eu/products) was used in model validation as well, as was data from the World Ocean Data (Locarnini et al., 2018; Zweng et al., 2019) (Text S6 in Supporting Information S1).

Attached Files

Published - 2021GL097211.pdf

Accepted Version - 2021GL097211-acc.pdf

Supplemental Material - 2021gl097211-sup-0001.pdf

Supplemental Material - 2021gl097211-sup-0002-movie_si-s01.mp4

Supplemental Material - 2021gl097211-sup-0003-movie_si-s02.mp4

Supplemental Material - 2021gl097211-sup-0004-movie_si-s03.mp4

Supplemental Material - 2021gl097211-sup-0005-movie_si-s04.mp4

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Additional details

Created:
October 9, 2023
Modified:
October 24, 2023