Direct measurements of western boundary currents off Brazil between 20°S and 28°S

Müller, Thomas J.; Ikeda, Yoshimine; Zangenberg, Norbert; Nonato, Luiz V.

doi:10.1029/97jc03529

Cited by 86 publications

(85 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On A10 we constrain the Brazil Current and its recirculation based on the work of Zemba (1991). The southward transport of the Brazil Current that we use (25 Ϯ 10 Sv) is consistent with the transport of 22.4 Ϯ 11.3 Sv that Müller et al (1998) deduced from currentmeter records. A detailed study of the Vema Channel has shown a southward recirculation of 1.5 Sv of bottom water on the eastern flank of the Vema Channel (McDonagh et al 2002).…”

Section: Constraintsmentioning

confidence: 78%

Oceanic Fluxes in the South Atlantic

McDonagh

King

2005

Journal of Physical Oceanography

View full text Add to dashboard Cite

A box inverse of the World Ocean Circulation Experiment A10 (30°S) and A11 (nominally 45°S) sections in the South Atlantic Ocean was undertaken. The authors find a heat flux across A10 of 0.22 Ϯ 0.08 PW, consistent with previous studies, and a heat flux of 0.43 Ϯ 0.08 PW across A11. The A11 heat flux is lower than some previous analyses of this section but implies a plausible oceanic heat convergence (heat loss to the atmosphere) of 0.21 Ϯ 0.10 PW. The difference is principally due to adding a cyclonic component to the circulation in the Cape Basin. As compared with the solution of other studies, the anticyclonic circulation in the surface and intermediate water of the subtropical gyre is weakened. The circulation of the deep water is cyclonic rather than anticyclonic; this is in better agreement with previously published circulation schemes based on examination of water properties. A southward freshwater flux of 0.7 Sv (1 Sv ϵ 10 6 m 3 s Ϫ1) at A11, consistent with previous inverse studies, is still inconsistent with the net Atlantic evaporation inferred from integrated surface climatologies. Results suggest a small gain of freshwater (0.2 Ϯ 0.1 Sv) between the sections.

show abstract

Section: Constraintsmentioning

confidence: 78%

Oceanic Fluxes in the South Atlantic

McDonagh

King

2005

Journal of Physical Oceanography

View full text Add to dashboard Cite

show abstract

“…The subtropical gyre center appears to be south-east of the Rio Grande Rise, separating the eastward advection of AAIW as deep South Atlantic Current (Stramma and Peterson, 1990) from the westward recirculation flow around 30°S. The subtropical circulation cell is closed in the east by the deep Benguela Current with pulses of more saline Intermediate Water from the Indian Ocean (Agulhas eddies, (Lutjeharms, 1996)) and in the west by the robustly increasing deep Brazil Current (Mu¨ller et al, 1996;Zangenberg and Siedler, 1997). It is drained by a narrow, though swift northward Intermediate Western Boundary Current beneath the Brazil Current.…”

Section: Introductionmentioning

confidence: 99%

Kinematic elements of Antarctic Intermediate Water in the western South Atlantic

Boebel

Schmid

Zenk

1999

Deep Sea Research Part II: Topical Studies in Oceanography

View full text Add to dashboard Cite

The northward flowing Antarctic Intermediate Water (AAIW) is a major contributor to the large-scale meridional circulation of water masses in the Atlantic. Together with bottom and thermocline water, AAIW replaces North Atlantic Deep Water that penetrates into the South Atlantic from the North. On the northbound propagation of AAIW from its formation area in the south-western region of the Argentine Basin, the AAIW progresses through a complex spreading pattern at the base of the main thermocline. This paper presents trajectories of 75 subsurface floats, seeded at AAIW depth. The floats were acoustically tracked, covering a period from December 1992 to October 1996. Discussions of selected trajectories focus on mesoscale kinematic elements that contribute to the spreading of AAIW. In the equatorial region, intermittent westward and eastward currents were observed, suggesting a seasonal cycle of the AAIW flow direction. At tropical latitudes, just offshore the intermediate western boundary current, the southward advection of an anticyclonic eddy was observed between 5°S and 11°S. Farther offshore, the flow lacks an advective pattern and is governed by eddy diffusion. The westward subtropical gyre return current at about 28°S shows considerable stability, with the mean kinetic energy to eddy kinetic energy ratio being around one. Farther south, the eastward deeper South Atlantic Current is dominated by large-scale meanders with particle velocities in excess of 60 cm s\ . At the Brazil-Falkland Current Confluence Zone, a cyclonic eddy near 40°S 50°W seems to act as injector of freshly mixed AAIW into the subtropical gyre. In general, much of the mixing of the various blends of AAIW is due to the activity of mesoscale eddies, which frequently reoccupy similar positions.

show abstract

“…The only direct current meter estimates available in the region are from off Cabo Frio (22 • S) and Cabo Santa Marta (28 • S). These 23-month records indicate a very weak southward volume transport by the DWBC: −0.5 ± 1.6 and −2.8 ± 4.9 Sv (1 Sv = 10 6 m 3 s −1 ), respectively (Müller et al, 1998). The southward geostrophic transport at the western boundary at 28 • S is estimated at 10 Sv, but about 4 Sv recirculate northward in the interior (Zangenberg and Siedler, 1998).…”

Section: Introductionmentioning

confidence: 99%

Deep Western Boundary Current transport variability in the South Atlantic: preliminary results from a pilot array at 34.5° S

et al. 2012

View full text Add to dashboard Cite

Abstract. The first direct estimates of the temporal variability of the absolute transport in the Deep Western Boundary Current (DWBC) at 34.5 • S in the South Atlantic Ocean are obtained using just under one year of data from a line of four pressure-equipped inverted echo sounders. Hydrographic sections collected in 2009 and 2010 confirm, based on neutral density, temperature, salinity, and oxygen values, the presence of the DWBC, one of the main deep pathways of the Meridional Overturning Circulation. Both data sets indicate that the DWBC reconstitutes itself after breaking into eddies in the western sub-tropical Atlantic near 8 • S. The amplitude and spectral character of the DWBC transport variability are comparable with those observed in the North Atlantic, where longer records exist, with the DWBC at 34.5 • S exhibiting a transport standard deviation of 25 Sv and variations of ∼ 40 Sv occurring within periods as short as a few days. There is little indication of an annual cycle in the DWBC transports, although the observational records are too short to be definitive. A Monte Carlo-style analysis using 27 yr of model output from the same location as the observations indicates that about 48-60 months of data will be required to fully assess the deep transport variability. The model suggests the presence of an annual cycle in DWBC transport, however its statistical significance with even 27 yr of model output is low, suggesting that seasonal variations in the model are weak.

show abstract

Direct measurements of western boundary currents off Brazil between 20°S and 28°S

Cited by 86 publications

References 28 publications

Oceanic Fluxes in the South Atlantic

Oceanic Fluxes in the South Atlantic

Kinematic elements of Antarctic Intermediate Water in the western South Atlantic

Deep Western Boundary Current transport variability in the South Atlantic: preliminary results from a pilot array at 34.5° S

Contact Info

Product

Resources

About