Near-inertial motions in the Brazil Current at 24°S-36°S: Observations by satellite tracked drifters

Assireu, Arcilan Trevenzoli; Dauhut, Thibaut; Santos, Francisco Alves dos; Lorenzzetti, João A.

doi:10.1016/j.csr.2017.07.005

Cited by 7 publications

(11 citation statements)

References 61 publications

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“…Hourly surface fields from the fifth generation of the European Center for Medium‐Range Weather Forecasts (ECMWF) global reanalysis (ERA5; Hersbach et al., 2020) with 0.25° resolution were used to force ROMS surface with heat, momentum and fresh water fluxes. Therefore, the temporal resolution of the atmospheric forcing was high enough so that the near‐inertial motions of the ocean in south/southeastern Brazil, with periods between 20.9 and 29.5 hr (Assireu et al., 2017), were not filtered out or diminished.…”

Section: Methodsmentioning

confidence: 99%

“…The continental shelf circulation in the region is strongly influenced by winds, generally flowing southwestward along the coast under the influence of winds from NE, and flowing northeastward when the wind turns from SW/SE (Möller et al., 2008). Such a shift in wind direction normally exists during the passage of cold fronts in the region and is a potential generation mechanism of NICs (Assireu et al., 2017). Following the results of Assireu et al.…”

Section: Study Regionmentioning

confidence: 99%

“…Besides, Assireu et al. (2017) evidenced that near‐inertial currents may account for up to 45% of the total surface current variance in the BC region of south/southeastern Brazil, which can significantly affect wave highs (Gemmrich & Garrett, 2012).…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Currents on Large Surface Gravity Waves Under Cyclonic Conditions in the South/Southeastern Brazil

2023

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Although ocean surface currents are not accounted for in most wave modeling studies, recent works have demonstrated that ocean circulation features may have a great impact on surface gravity waves. In this case study, we coupled in a one‐way mode the hydrodynamic model Regional Ocean Modeling System (ROMS) and the wave model Simulating WAves Nearshore (SWAN) to study the effect of currents on large wave events (LWEs) produced under the influence of cyclones in south/southeastern Brazil. For the five LWEs studied, chosen due to the distinct importance that current‐to‐wave effects had for the period, the results indicate that the addition of currents on the wave model improved the accuracy of the peaks of significant wave height, generally increasing them (by as much as 27%). The increase in wave height occurred mainly near the shelf edge and slope, where the southwestward‐flowing Brazil Current opposes the dominant direction of cyclone‐generated waves (usually from S/SE to S/SW). Modulation of wave height by currents in the subinertial band explained up to 95% of the total variance of the difference between results with and without ocean currents, and this band was largely related to the Brazil Current. Its near‐inertial counterpart explained up to 22% of the total variance and was primarily due to near‐inertial currents in the region. This study provides, for the first time, conclusive evidence that wave‐current interaction can impact LWEs in south/southeastern Brazil.

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Section: Methodsmentioning

confidence: 99%

Section: Study Regionmentioning

confidence: 99%

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The Effect of Currents on Large Surface Gravity Waves Under Cyclonic Conditions in the South/Southeastern Brazil

2023

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“…The BC flows southwestwards along the outer shelf and upper slope with maximum speeds of up to 0.6 m s-1 (Biló et al, 2014); it is intensified south of 24 • S due to the contribution of recirculation cells (Stramma and England, 1999). Along the Santos and Pelotas basins, the BC is prone to strong meandering and eddy shedding, and these features are associated with a southward increase in eddy kinetic energy (Fernandes et al, 2009;Assireu et al, 2017;Magalhães et al, 2017). The meandering pattern of the BC is evidenced by the occurrence of seawarddirected bedforms indicating the direction of sediment transport, suggesting sediment export from the shelf to the slope.…”

Section: Physical Oceanographymentioning

confidence: 99%

Geomorphological imprint of opposing ocean bottom currents, a case study from the southeastern Brazilian Atlantic margin

et al. 2022

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“…The Brazil Current is crucial in determining the sedimentary balance of the outer shelf, shelf‐edge and upper slope of the Brazilian margin. The eddy kinetic energy of quasi‐permanent meanders and vortices of the Brazil Current intensifies southwards (e.g., Assireu, Dauhut, Santos, & Lorenzzetti, ). Further south, the Brazilian Coastal Current (BCC in Figure ) flows most of the year along the inner Uruguay and Pelotas shelves to the northeast, paralleling the Brazil Current but in the opposite direction, up to the centre of the Santos shelf (Mendoça et al, ; de Souza & Robinson, ).…”

Section: Regional Settingmentioning

confidence: 99%

What feeds shelf‐edge clinoforms over margins deprived of adjacent land sources? An example from southeastern Brazil

et al. 2019

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In southeastern Brazil, the Serra do Mar coastal mountain range blocks the sediment influx from arriving at a ca. 1,500 km long continental margin comprising Santos and Pelotas basins. Despite this deprivation, the margin accumulated a ca. 1 km thick sedimentary succession since the Mid‐Miocene. Examination of seismic reflection and oceanographic data indicates that shelf‐margin clinoform formation exhibits a regional variability, with major sigmoidal clinoforms developed in the transitional area between both basins. Laterally, poorly developed oblique clinoforms constitute isolated depocenters along the shelf margin. The continuous clinoform development in the transitional area is attributed to the major influence on sediment transport patterns of several ocean bottom currents flowing along the margin, such as the Brazil Coastal Current, the Brazil Current and the Intermediate Water Brazil Current. These currents erode, transport and distribute sediments across the shelf break and upper slope from distant sediment sources located either north or south of the study area. The progressive southward strengthening of the Brazil Current could be responsible for a major southward sediment redistribution from the northern Campos Basin, and/or for sediment entrainment from northward‐induced transport by the Brazil Coastal Current, originally derived from the De la Plata Estuary. In the transition between Santos and Pelotas basins, the Intermediate Water Brazil Current splits forming the Santos Bifurcation, allowing for a continuous depositional process and clinoform generation. We suggest that ocean bottom currents may shape other shelf‐edge ‘contouritic clinoforms’ in continental margins mainly constructed by along‐strike sediment transport largely driven by long‐term geostrophic currents.

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Near-inertial motions in the Brazil Current at 24°S-36°S: Observations by satellite tracked drifters

Cited by 7 publications

References 61 publications

The Effect of Currents on Large Surface Gravity Waves Under Cyclonic Conditions in the South/Southeastern Brazil

The Effect of Currents on Large Surface Gravity Waves Under Cyclonic Conditions in the South/Southeastern Brazil

Geomorphological imprint of opposing ocean bottom currents, a case study from the southeastern Brazilian Atlantic margin

What feeds shelf‐edge clinoforms over margins deprived of adjacent land sources? An example from southeastern Brazil

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