The fate of the Deep Western Boundary Current in the South Atlantic

Silvia L. Garzoli, Shenfu Dong, Rana A Fine, Christopher S. Meinen, Renellys C. Perez, Claudia Schmid, Erik Van Sebille, Qi Yao

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The pathways of recently ventilated North Atlantic Deep Water (NADW) are part of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). In the South Atlantic these pathways have been the subject of discussion for years, mostly due to the lack of observations. Knowledge of the pathways of the AMOC in the South Atlantic is a first order prerequisite for understanding the fluxes of climatically important properties. In this paper, historical and new observations, including hydrographic and oxygen sections, Argo data, and chlorofluorocarbons (CFCs), are examined together with two different analyzes of the Ocean general circulation model For the Earth Simulator (OFES) to trace the pathway of the recently ventilated NADW through the South Atlantic. CLIVAR-era CFCs, oxygen and salinity clearly show that the strongest NADW pathway in the South Atlantic is along the western boundary (similar to the North Atlantic). In addition to the western boundary pathway, tracers show an eastward spreading of NADW between ~17 and 25°S. Analyzed together with the results of earlier studies, the observations and model output presented here indicate that after crossing the equator, the Deep Western Boundary Current (DWBC) transports water with the characteristics of NADW and a total volume transport of approximately 14Sv (1Sv=10<sup>6</sup>m<sup>3</sup>s<sup>-</sup><sup>1</sup>). It crosses 5°S as a narrow western boundary current and becomes dominated by eddies further south. When this very energetic eddying flow reaches the Vitória-Trindade Ridge (~20°S), the flow follows two different pathways. The main portion of the NADW flow continues along the continental shelf of South America in the form of a strong reformed DWBC, while a smaller portion, about 22% of the initial transport, flows towards the interior of the basin.

Original languageEnglish (US)
Pages (from-to)125-136
Number of pages12
JournalDeep-Sea Research Part I: Oceanographic Research Papers
Volume103
DOIs
StatePublished - Sep 1 2015

Fingerprint

North Atlantic Deep Water
western boundary current
chlorofluorocarbons
CFC
water
meridional circulation
oxygen
volume transport
General Circulation Models
Argo
water flow
simulator
limb
general circulation model
tracer techniques
continental shelf
eddy
energetics
oceans
tracer

Keywords

  • Deep Western Boundary Current
  • Meridional Overturning Circulation
  • North Atlantic Deep Water
  • South Atlantic Circulation

ASJC Scopus subject areas

  • Aquatic Science
  • Oceanography

Cite this

The fate of the Deep Western Boundary Current in the South Atlantic. / Garzoli, Silvia L.; Dong, Shenfu; Fine, Rana A; Meinen, Christopher S.; Perez, Renellys C.; Schmid, Claudia; Van Sebille, Erik; Yao, Qi.

In: Deep-Sea Research Part I: Oceanographic Research Papers, Vol. 103, 01.09.2015, p. 125-136.

Research output: Contribution to journalArticle

Garzoli, Silvia L. ; Dong, Shenfu ; Fine, Rana A ; Meinen, Christopher S. ; Perez, Renellys C. ; Schmid, Claudia ; Van Sebille, Erik ; Yao, Qi. / The fate of the Deep Western Boundary Current in the South Atlantic. In: Deep-Sea Research Part I: Oceanographic Research Papers. 2015 ; Vol. 103. pp. 125-136.
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AU - Garzoli, Silvia L.

AU - Dong, Shenfu

AU - Fine, Rana A

AU - Meinen, Christopher S.

AU - Perez, Renellys C.

AU - Schmid, Claudia

AU - Van Sebille, Erik

AU - Yao, Qi

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