Abstract:

Antarctic Bottom Water (AABW), which fills the global ocean abyss, is derived from dense water which 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 of blending between AABW sourced from distinct source regions 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. North-wards 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.

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