Variability of the Deep Western Boundary Current at 26.5°N during 2004-2009

Christopher S. Meinen, William E Johns, Silvia L. Garzoli, Erik van Sebille, Darren Rayner, Torsten Kanzow, Molly O. Baringer

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Five years of data from a line of dynamic height moorings (DHM), bottom-pressure recorders (BPR), and pressure-equipped inverted echo sounders (PIES) near the Atlantic Ocean western boundary at 26.5°N are used to evaluate the structure and variability of the Deep Western Boundary Current (DWBC) during 2004-2009. Comparisons made between transports estimated from the DHM+BPR and those made by the PIES demonstrate that the two systems are collecting equivalent volume transport information (correlation coefficient r=0.96, root-mean-square difference=6Sv; 1Sv=106m3s-1). Integrated to ~450km off from the continental shelf and between 800 and 4800dbar, the DWBC has a mean transport of approximately 32Sv and a standard deviation during these five years of 16Sv. Both the barotropic (full-depth vertical mean) and baroclinic flows have significant variability (changes exceeding 10Sv) on time scales ranging from a few days to months, with the barotropic variations being larger and more energetic at all time scales. The annual cycle of the deep transport is highly dependent on the horizontal integration distance; integrating ~100km offshore yields an annual cycle of roughly similar magnitude but shifted in phase relative to that found from current meter arrays in the 1980-1990s, while the annual cycle becomes quite weak when integrating ~450km offshore. Variations in the DWBC transport far exceed those of the total basin-wide Meridional Overturning Circulation (standard deviations of 16Sv vs. 5Sv). Transport integrated in the deep layer out to the west side of the Mid-Atlantic Ridge still demonstrates a surprisingly high variance, indicating that some compensation of the western basin deep variability must occur in the eastern basin.

Original languageEnglish (US)
Pages (from-to)154-168
Number of pages15
JournalDeep-Sea Research Part II: Topical Studies in Oceanography
Volume85
DOIs
StatePublished - Jan 2013
Externally publishedYes

Fingerprint

western boundary current
annual cycle
bottom pressure
basin
baroclinic motion
timescale
volume transport
meridional circulation
continental shelf
energetics
ocean

Keywords

  • Deep Western Boundary Current
  • Inverted Echo Sounder
  • Meridional Overturning Circulation
  • Thermohaline
  • Transport
  • Variability

ASJC Scopus subject areas

  • Oceanography

Cite this

Variability of the Deep Western Boundary Current at 26.5°N during 2004-2009. / Meinen, Christopher S.; Johns, William E; Garzoli, Silvia L.; van Sebille, Erik; Rayner, Darren; Kanzow, Torsten; Baringer, Molly O.

In: Deep-Sea Research Part II: Topical Studies in Oceanography, Vol. 85, 01.2013, p. 154-168.

Research output: Contribution to journalArticle

Meinen, Christopher S. ; Johns, William E ; Garzoli, Silvia L. ; van Sebille, Erik ; Rayner, Darren ; Kanzow, Torsten ; Baringer, Molly O. / Variability of the Deep Western Boundary Current at 26.5°N during 2004-2009. In: Deep-Sea Research Part II: Topical Studies in Oceanography. 2013 ; Vol. 85. pp. 154-168.
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