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 and Baringer, Molly O. (2013) Variability of the Deep Western Boundary Current at 26.5°N during 2004–2009. Deep-Sea Research Part II-Topical Studies in Oceanography, 85 . pp. 154-168. DOI 10.1016/j.dsr2.2012.07.036.

[img] Text
meinen.pdf - Published Version
Restricted to Registered users only

Download (1962Kb) | Contact

Supplementary data:

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=6 Sv; 1 Sv=106 m3 s−1). Integrated to ∼450 km off from the continental shelf and between 800 and 4800 dbar, the DWBC has a mean transport of approximately 32 Sv and a standard deviation during these five years of 16 Sv. Both the barotropic (full-depth vertical mean) and baroclinic flows have significant variability (changes exceeding 10 Sv) 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 ∼100 km 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 ∼450 km offshore. Variations in the DWBC transport far exceed those of the total basin-wide Meridional Overturning Circulation (standard deviations of 16 Sv vs. 5 Sv). 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.

Document Type: Article
Keywords: Meridional Overturning Circulation; Deep Western Boundary Current; Transport; Inverted EchoSounder; Thermohaline; Variability
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.dsr2.2012.07.036
ISSN: 0967-0645
Date Deposited: 30 Nov 2012 10:44
Last Modified: 18 Oct 2016 09:41
URI: http://oceanrep.geomar.de/id/eprint/19428

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...