The imprint of Southern Ocean overturning on seasonal water mass variability in Drake Passage
The imprint of Southern Ocean overturning on seasonal water mass variability in Drake Passage
Seasonal changes in water mass properties are discussed in thermohaline coordinates from a seasonal climatology and repeat hydrographic sections. The SR1b CTD transects along Drake Passage are used as a case study. The amount of water within temperature and salinity classes and changes therein are used to estimate dia-thermal and dia-haline transformations. These transformations are considered in combination with climatologies of surface buoyancy flux to determine the relative contributions of surface buoyancy fluxes and subsurface mixing to changes in the distribution of water in thermohaline coordinates. The framework developed provides unique insights into the thermohaline circulation of the water masses that are present within Drake Passage, including the erosion of Antarctic Winter Water (AAWW) during the summer months and the interaction between the Circumpolar Deep Waters (CDW) and Antarctic Intermediate Water (AAIW). The results presented are consistent with summertime wind-driven inflation of the CDW layer and deflation of the AAIW layer, and with new AAIW produced in the winter as a mixture of CDW, remnant AAWW, and surface waters. This analysis therefore highlights the role of surface buoyancy fluxes in the Southern Ocean overturning.
southern ocean overturning, drake passage, water masses, thermohaline coordinates, in situ observations
7987-8010
Evans, Dafydd Gwyn
4e1ed170-9119-4b35-a45f-55f8d07fa24e
Zika, Jan D.
1843cce7-77ce-4ef6-9f79-bcf4f9db30e5
Naveira Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Nurser, A.J. George
2493ef9a-21e9-4d8b-9c32-08677e7e145a
November 2014
Evans, Dafydd Gwyn
4e1ed170-9119-4b35-a45f-55f8d07fa24e
Zika, Jan D.
1843cce7-77ce-4ef6-9f79-bcf4f9db30e5
Naveira Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Nurser, A.J. George
2493ef9a-21e9-4d8b-9c32-08677e7e145a
Evans, Dafydd Gwyn, Zika, Jan D., Naveira Garabato, Alberto C. and Nurser, A.J. George
(2014)
The imprint of Southern Ocean overturning on seasonal water mass variability in Drake Passage.
Journal of Geophysical Research, 119 (11), .
(doi:10.1002/2014JC010097).
Abstract
Seasonal changes in water mass properties are discussed in thermohaline coordinates from a seasonal climatology and repeat hydrographic sections. The SR1b CTD transects along Drake Passage are used as a case study. The amount of water within temperature and salinity classes and changes therein are used to estimate dia-thermal and dia-haline transformations. These transformations are considered in combination with climatologies of surface buoyancy flux to determine the relative contributions of surface buoyancy fluxes and subsurface mixing to changes in the distribution of water in thermohaline coordinates. The framework developed provides unique insights into the thermohaline circulation of the water masses that are present within Drake Passage, including the erosion of Antarctic Winter Water (AAWW) during the summer months and the interaction between the Circumpolar Deep Waters (CDW) and Antarctic Intermediate Water (AAIW). The results presented are consistent with summertime wind-driven inflation of the CDW layer and deflation of the AAIW layer, and with new AAIW produced in the winter as a mixture of CDW, remnant AAWW, and surface waters. This analysis therefore highlights the role of surface buoyancy fluxes in the Southern Ocean overturning.
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e-pub ahead of print date: 25 November 2014
Published date: November 2014
Keywords:
southern ocean overturning, drake passage, water masses, thermohaline coordinates, in situ observations
Organisations:
Marine Systems Modelling, Physical Oceanography
Identifiers
Local EPrints ID: 372139
URI: http://eprints.soton.ac.uk/id/eprint/372139
ISSN: 0148-0227
PURE UUID: bef06eae-e403-4beb-a0fc-0e1b12fb18c3
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Date deposited: 26 Nov 2014 09:47
Last modified: 15 Mar 2024 03:24
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Author:
Dafydd Gwyn Evans
Author:
Jan D. Zika
Author:
A.J. George Nurser
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