Subantarctic mode water: distribution and circulation
Subantarctic mode water: distribution and circulation
The subduction and export of subantarctic mode water (SAMW) as part of the overturning circulation play an important role in global heat, freshwater, carbon and nutrient budgets. Here, the spatial distribution and export of SAMW is investigated using Argo profiles and a climatology. SAMW is identified by a dynamical tracer: a minimum in potential vorticity. We have found that SAMW consists of several modes with distinct properties in each oceanic basin. This conflicts with the previous view of SAMW as a continuous water mass that gradually cools and freshens to the east. The circulation paths of SAMW were determined using (modified) Montgomery streamlines on the density surfaces corresponding with potential vorticity minima. The distribution of the potential vorticity minima revealed “hotspots” where the different SAMW modes subduct north of the Subantarctic Front. The subducted SAMWs follow narrow export pathways into the subtropical gyres influenced by topography. The export of warmer, saltier modes in these “hotspots” contributes to the circumpolar evolution of mode water properties toward cooler, fresher and denser modes in the east.
Subantarctic mode water, Potential vorticity, Montgomery streamfunction, Circulation, Spatial distribution
103-126
Herraiz-Borreguero, Laura
faa962ba-19f8-4cf3-83be-ee4972fdbe9f
Rintoul, Stephen Rich
af574aef-132c-43b5-be4e-a9d12da1602d
January 2011
Herraiz-Borreguero, Laura
faa962ba-19f8-4cf3-83be-ee4972fdbe9f
Rintoul, Stephen Rich
af574aef-132c-43b5-be4e-a9d12da1602d
Herraiz-Borreguero, Laura and Rintoul, Stephen Rich
(2011)
Subantarctic mode water: distribution and circulation.
Ocean Dynamics, 61 (1), .
(doi:10.1007/s10236-010-0352-9).
Abstract
The subduction and export of subantarctic mode water (SAMW) as part of the overturning circulation play an important role in global heat, freshwater, carbon and nutrient budgets. Here, the spatial distribution and export of SAMW is investigated using Argo profiles and a climatology. SAMW is identified by a dynamical tracer: a minimum in potential vorticity. We have found that SAMW consists of several modes with distinct properties in each oceanic basin. This conflicts with the previous view of SAMW as a continuous water mass that gradually cools and freshens to the east. The circulation paths of SAMW were determined using (modified) Montgomery streamlines on the density surfaces corresponding with potential vorticity minima. The distribution of the potential vorticity minima revealed “hotspots” where the different SAMW modes subduct north of the Subantarctic Front. The subducted SAMWs follow narrow export pathways into the subtropical gyres influenced by topography. The export of warmer, saltier modes in these “hotspots” contributes to the circumpolar evolution of mode water properties toward cooler, fresher and denser modes in the east.
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Published date: January 2011
Keywords:
Subantarctic mode water, Potential vorticity, Montgomery streamfunction, Circulation, Spatial distribution
Organisations:
Physical Oceanography
Identifiers
Local EPrints ID: 398667
URI: http://eprints.soton.ac.uk/id/eprint/398667
ISSN: 1616-7341
PURE UUID: 02af4efd-3d6b-45ac-b46e-f19f29e3f15b
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Date deposited: 28 Jul 2016 15:56
Last modified: 15 Mar 2024 01:38
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Author:
Laura Herraiz-Borreguero
Author:
Stephen Rich Rintoul
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