Upper ocean circulation in the western tropical Atlantic in boreal fall 2000

Stramma, Lothar; Rhein, Monika; Brandt, Peter; Dengler, Marcus; Böning, Claus W.; Walter, Maren

doi:10.1016/j.dsr.2004.07.021

Cited by 60 publications

(69 citation statements)

References 34 publications

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“…The northern branch of the sSEC termination flows northward, forming the North Brazil Current/North Brazil Undercurrent (NBC/NBUC) system. This powerful western boundary current contributes to the northward Guyana Current Stramma et al, 2005) and to the eastward North Equatorial Counter Current (NECC). It also feeds its associated complex retroflection system (Goes et al, 2005), as well as the eastward Equatorial Undercurrent (EUC).…”

Section: Introductionmentioning

confidence: 99%

Salinity-induced mixed and barrier layers in the southwestern tropical Atlantic Ocean off the northeast of Brazil

et al. 2011

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Section: Introductionmentioning

confidence: 99%

Salinity-induced mixed and barrier layers in the southwestern tropical Atlantic Ocean off the northeast of Brazil

et al. 2011

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“…Many eddies along the coast mask the bifurcation of the sSEC. In the Figure 3.7 the simulation show that the sSEC reaches the Brazilian shelf between 13°S and 15°S, for April, May and June diverging into two western boundary currents; flowing to the north as North Brazil Undercurrent -NBUC, and to the south as the Brazil Current -BC (STRAMMA and ENGLAND, 1999;Stramma et al, 2005;Schott et al, 2005). For the months October, November and December the meridional component is reverse about 12°S.…”

Section: Veleda D R a Et Al Seasonal And Interannual Variabilitymentioning

confidence: 99%

“…After passing Cape São Roque at 5°S, the central band of SEC (cSEC) joins the NBUC, causing its vertical structure to change from an undercurrent to a surface-intensified current, namely the North Brazil Current (NBC). The NBC crosses the equator northwestward and retroflects into the zonal equatorial current system (SILVEIRA et al, 1994;STRAMMA et al, 1990STRAMMA et al, , 1995STRAMMA et al, , 2005SCHOTT et al, 1998). The NBUC has a mean northward transport of ~25.4 Sv along the northern coastline of Brazil and a seasonal cycle of 2.5 Sv amplitude with its northward maximum in July, while the interannual NBUC transport variations are small, varying only by 1.2 Sv, with no detectable trend (SCHOTT et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The Deep Western Boundary Current (DWBC) transports cold NADW toward the southern hemisphere, while the NBUC flows as a inter-hemispheric conduit of warm surface waters northward to close the thermohaline overturning cell (GORDON, 1986;SCHMITZ, 1995). The SACW, between 100 and 500 m depth, is transported within the sSEC toward the Brazilian shelf, where it is carried toward the equator via NBUC and NBC (STRAMMA and SCHOTT, 1999;STRAMMA et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The western boundary regime of the tropical South Atlantic in its several scales of variability has been the subject of numerous investigations (MOLINARI, 1983;STRAMMA, 1991;STRAMMA et al, 1995;STRAMMA and SCHOTT, 1999;STRAMMA et al, 2005;SCHOTT and BÖNING, 1991;SCHOTT et al, 1993;RHEIN et al, 1995;SCHOTT et al, 2005). The Deep Western Boundary Current (DWBC) transports cold NADW toward the southern hemisphere, while the NBUC flows as a inter-hemispheric conduit of warm surface waters northward to close the thermohaline overturning cell (GORDON, 1986;SCHMITZ, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Seasonal and interannual variability of the southern south Equatorial Current bifurcation and meridional transport along the eastern brazilian edge.

Veleda¹,

Araújo²,

Silva³

et al. 2011

TropOcean

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The dynamics of the southern band of the South Equatorial Current (sSEC) near to Brazilian shelf is investigated using recent field observations and a regional numerical modeling approach. The field measurements were obtained from five moorings deployed by German CLIVAR (Climate Variability and Predictability Program) cruises (March 2000-August 2004) along a crossshore line at 11oS. The Regional Ocean Model (ROMS) is used to simulate the circulation and thermohaline structures within the ocean area comprised between 5°S-25°S and 20°W-47°W. This integration domain was covered by an isotropic 1/12o horizontal grid and 40 terrain-following layers. The numerical results confirm a seasonal migration of the sSEC divergence along the Brazilian edge, as well as its depth dependence with a maximum southward shift in July at 200 m depth, while a maximum northward displacement occurs in November at this same depth. This intrannual variability coincides with the North Brazil Undercurrent (NBUC) seasonality at 11oS from moorings measurements. Empirical Orthogonal Function (EOF) and numerical results show a minimum NBUC strength during November and a maximum northward transport in July. The mean transport from field measurements is 25Sv while this from numerical simulations is 24.5Sv. The SODA reanalysis with 47 years of monthly mean indicates that the sSEC has not only a seasonal variability as well as quasi-biannual variability.

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Short‐term upwelling events at the western African coast related to synoptic atmospheric structures as derived from satellite observations

2014

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[1] Satellite scatterometers provide continuously valuable surface wind speed and direction estimates over the global ocean on a regular grid both in space and time. The Level 3 data derived from the Advanced Scatterometer (ASCAT), available at 1/4 spatial resolution (hereafter AS25), and Quick Scatterometer (QuikSCAT), available on 1/2 and 1/4 horizontal grids (QS50 and QS25, respectively), are studied at regional scales in both the Benguela and Canary upwelling systems. They are compared to the European Center for Medium-Range Weather Forecast surface wind analysis, with insight into their intrinsic and actual spatial resolutions. In the coastal band, the finest spatial patterns are found in the QS25 winds and are O(75 km). This demonstrates the sensitivity of the high-resolution satellite-derived winds to coastal processes related to sea surface temperature (SST) perturbations and land-sea transition. Next, short-lived upwelling episodes (SUEs) calculated from SST anomalies are defined consistently with the QS25 actual resolution. These cold events refer to local, short-lived perturbations that add to seasonal upwelling variability. We characterize concomitant atmospheric synoptic conditions for SUEs identified at chosen latitudes and highlight two subregions in both upwelling systems, with contrasted patterns for the alongshore wind stress component and curl. The complexity of the latter patterns is closely linked to local, short-term SST variability. Closer to the shore, numerical sensitivity experiments show that the imbalance between Ekman transport and Ekman pumping has an impact on ocean dynamics: wind reduction in the coastal QS25 forcing, partially induced by orography, tends to reduce coastal SST cooling.

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Upper ocean circulation in the western tropical Atlantic in boreal fall 2000

Cited by 60 publications

References 34 publications

Salinity-induced mixed and barrier layers in the southwestern tropical Atlantic Ocean off the northeast of Brazil

Salinity-induced mixed and barrier layers in the southwestern tropical Atlantic Ocean off the northeast of Brazil

Seasonal and interannual variability of the southern south Equatorial Current bifurcation and meridional transport along the eastern brazilian edge.

Short‐term upwelling events at the western African coast related to synoptic atmospheric structures as derived from satellite observations

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