Wind-controlled export of Antarctic Bottom Water from the Weddell Sea

Recent studies suggest that the variability in Antarctic Bottom Water (AABW) properties in the Scotia Sea on time scales up to decadal may be linked to changes in the baroclinicity of the Weddell gyre, with vertical variations in the density structure at the gyre's northern edge acting to contr...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Jullion, L., Jones, S.C., Naveira Garabato, A.C., Meredith, M. P.
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2010
Subjects:
Marine Sciences
Meteorology and Climatology
Hydrology
Antarctic
Drake Passage
Meredith
Scotia Sea
South Scotia Ridge
Weddell
Weddell Sea
Antarc*
Online Access:http://nora.nerc.ac.uk/id/eprint/10541/
https://nora.nerc.ac.uk/id/eprint/10541/1/grl26971.pdf
http://www.agu.org/journals/gl/gl1009/2010GL042822/2010GL042822.pdf
Description
Summary:Recent studies suggest that the variability in Antarctic Bottom Water (AABW) properties in the Scotia Sea on time scales up to decadal may be linked to changes in the baroclinicity of the Weddell gyre, with vertical variations in the density structure at the gyre's northern edge acting to control the export of AABW over the South Scotia Ridge and toward the mid-latitude South Atlantic. We test this hypothesis by analysing the AABW properties in fifteen occupations of the SR1b hydrographic section (1993-2009) in eastern Drake Passage alongside possible forcings as derived from atmospheric reanalysis data. We show that variability in the wind stress over the Weddell gyre leads changes in AABW properties in the SR1b section by approximately five months. The sign of the lagged correlation is consistent with the notion of the AABW export from the Weddell Sea being controlled by the gyre's baroclinic adjustment to wind forcing on time scales of several months. Variability in the regional winds is found to be closely linked to the Southern Annular Mode (SAM). These results suggest that there may be a causal relationship between the SAM's positive tendency observed in recent decades and the subsequent warming of AABW detected across much of the Atlantic Ocean. Citation: Jullion, L., S. C. Jones, A. C. Naveira Garabato, and M. P. Meredith (2010), Wind-controlled export of Antarctic Bottom Water from the Weddell Sea, Geophys. Res. Lett., 37, L09609, doi:10.1029/2010GL042822.

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