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Meridional heat and salt transport across the Subantarctic Front by cold-core eddies

Citation

Patel, PS and Phillips, HE and Strutton, PG and Lenton, A and Llort, J, Meridional heat and salt transport across the Subantarctic Front by cold-core eddies, Journal of Geophysical Research: Oceans, 124, (2) pp. 981-1004. ISSN 2169-9275 (2019) [Refereed Article]


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DOI: doi:10.1029/2018JC014655

Abstract

Mesoscale eddies are ubiquitous in the Southern Ocean particularly in regions where the Antarctic Circumpolar Current interacts with topography. Eddies play a critical role in the meridional transport of heat and salt across the Antarctic Circumpolar Current. However, observations of the heat and salt content of eddies are extremely rare. Here we present new observations that characterize the three‐dimensional structure of a cyclonic (cold‐core) eddy generated at the Subantarctic Front south of Tasmania. Automated detection software is used with satellite altimetry to follow the eddy through the Subantarctic Zone. The physical properties at the center of the eddy are substantially modified from those near the formation region, indicating a strong transformation during the eddy's lifetime. The eddy carried heat and salt content anomalies relative to surrounding Subantarctic Zone waters of −0.5  0.1  1020J and −2.1  0.4  1012kg, respectively. Previous studies have not captured the full heat and salt content of eddies due to limited observations and have underestimated their content by a factor of 2 to 3 south of Tasmania. Applying the observed correlation between eddy‐elevated volume and eddy heat and salt content to the history of cyclonic eddies in the satellite altimeter record leads us to propose that about 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by cyclonic eddies entering the Subantarctic Zone. The freshwater contribution to the Subantarctic Zone by long‐lived cold‐core eddies is of the same order of magnitude as the Ekman flux in this region.

Item Details

Item Type:Refereed Article
Keywords:Southern Ocean, Subantarctic Zone, mesoscale eddies, poleward heat flux, heat content, salt content
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
UTAS Author:Patel, PS (Mr Ramkrushnbhai Patel)
UTAS Author:Phillips, HE (Dr Helen Phillips)
UTAS Author:Strutton, PG (Associate Professor Peter Strutton)
UTAS Author:Lenton, A (Dr Andrew Lenton)
UTAS Author:Llort, J (Dr Joan Llort Jordi)
ID Code:131113
Year Published:2019
Funding Support:Australian Research Council (DP160102870)
Deposited By:Oceans and Cryosphere
Deposited On:2019-03-04
Last Modified:2019-06-13
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