Tide-topography interaction along the eastern Brazilian shelf

Pereira, Adriene Ferreira; Belem, André L.; Castro, Belmiro Mendes de; Geremias, R.

doi:10.1016/j.csr.2005.04.008

Cited by 37 publications

(35 citation statements)

References 23 publications

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“…Because they can contribute significantly to deep ocean mixing, it is widely recognized that these internal waves play a significant role in global thermohaline circulation [ Munk and Wunsch , 1998]. Beyond that, due to increased mixing, particularly near the seabed where current shear may be large, they can be important for sediment transport [e.g., Puig et al , 2004] and enhance biological productivity by mixing nutrients vertically into the photic zone [e.g., Pereira et al , 2005].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current

Pereira¹,

Castro²,

Calado³

et al. 2007

J. Geophys. Res.

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[1] A fully three-dimensional nonlinear primitive equation ocean model is applied to study the semidiurnal internal tide in the South Brazil Bight under summer conditions. Along the shelf break and upper slope of this region, the upper layer (0-600 m) is occupied by the southward flowing Brazil Current. Several numerical experiments were conducted to investigate the generation and propagation of the M 2 internal tide. Using horizontally homogeneous and vertically stratified density fields, internal tides were generated over the whole Bight with a clear signal on the continental shelf. When a more realistic summer stratification was considered, a baroclinic jet, representative of the Brazil Current, developed and comparisons between current observations and modeled results were improved. This jet acts as a barrier to the coastward propagation of the internal tide generated over the slope, reflecting it back towards the open ocean. On the negative relative vorticity side of the Brazil Current, located over the shelf, internal tides are trapped, enhancing vertical current variability and, hence, tidally induced mixing. The results highlight the importance of considering background flows when investigating internal tides in regions of strong along-slope baroclinic flows such as western boundary currents.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current

Pereira¹,

Castro²,

Calado³

et al. 2007

J. Geophys. Res.

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“…Below the TW the BC also carries the South Atlantic Central Water (SACW) usually with high nutrient concentrations. Although not well understood, there are evidences that the upwelled SACW in the Cabo Frio region may be advected by coastal currents to the Banco dos Abrolhos (CASTRO et al, 2006;PEREIRA et al, 2005), an indication that oceanic, coastal and estuarine systems are closely interconnected.…”

Section: Physical Settingmentioning

confidence: 99%

Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

Schettini

Miranda

2010

Braz. j. oceanogr.

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A B S T R A C TThe circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearlysynoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms -1 ) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms -1 ) and the peak flood currents were 0.75 and 0.60 ms -1 , respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m 3 s -1 at the ebb and flood, respectively, with a residual -630 m 3 s -1 . The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L -1 at the estuary mouth, to 10 mg.L -1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle. R E S U M OA circulação e o transporte de material particulado em suspensão no Estuário de Caravelas são pesquisados. Dados quase-sinóticos hidrográficos, de correntes (velocidade e transporte de volume com ADCP) e de material particulado em suspensão, foram medidos em intervalos horários durante um ciclo semidiurno de maré de sizígia, em duas seções transversais na Boca do Tomba e na Barra Velha e também em seções longitudinais na baixa-mar e na preamar. Na primeira transversal as correntes máximas de vazante (-1,50 m s -1 ) foram quase duas vezes mais intensas do que na seção transversal mais larga e rasa Barra Velha, (-0,80 m s -1 ) e as maiores velocidades das correntes de enchente foram de 0,75 m s -1 e 0,60 m s -1 , respectivamente. Devido à grande intensidade das correntes de maré, nas duas seções transversais a salinidade apresentou-se fracamente estratificada, sendo classificadas com o Diagrama Estratificação-circulação do Tipo 2a (parcialmente misturada e fraca estratificação vertical) e do Tipo 1a (bem misturada). Os transportes de volume foram muito próximos, variando de -3.500 m 3 s -1 a 3.100 m 3 s -1 , na vazante e na enchente, respectivamente, com um transporte de volume residual igual a -630 m 3 s -1 . A concentração do material particulado em suspensão (MPS) esteve fortemente relacionado à variação da maré, decrescendo estuário acima de 50 mg.L -1 , na boca do estuário, para 10 mg.L -1 para distâncias de 9 km e 16 km nos experimentos na baixa-mar e preamar, respectivamente. O transporte residual de MPS foi estuário abaixo com uma taxa estimada em -18 ton por ciclo de maré.

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“…The peculiarity of this hotspot lies not only in the fact that it is framed between two regions distinguished by different dynamics-the GoC mainly characterised by long-term seasonal variability, and the SoG highly influenced by the tidal cycle-but also because of its bathymetry [24]. The interaction of the tidal cycle with bathymetry allows the upwelling of cold and nutrient-rich waters [24,[48][49][50][51]. Phytoplankton, characterised by fast-growing cells, responds rapidly to this tidal-induced mixing that fertilises illuminated surface waters.…”

Section: Discussionmentioning

confidence: 99%

High-Chlorophyll-Area Assessment Based on Remote Sensing Observations: The Case Study of Cape Trafalgar

et al. 2018

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Cape Trafalgar has been highlighted as a hotspot of high chlorophyll concentrations, as well as a source of biomass for the Alborán Sea. It is located in an unique geographical framework between the Gulf of Cádiz (GoC), which is dominated by long-term seasonal variability, and the Strait of Gibraltar, which is mainly governed by short-term tidal variability. Furthermore, here bathymetry plays an important role in the upwelling of nutrient-rich waters. In order to study the spatial and temporal variability of chlorophyll-a in this region, 10 years of ocean colour observations using the MEdium Resolution Imaging Spectrometer (MERIS) were analysed through different approaches. An empirical orthogonal function decomposition distinguished two coastal zones with opposing phases that were analysed by wavelet methods in order to identify their temporal variability. In addition, to better understand the physical-biological interaction in these zones, the co-variation between chlorophyll-a and different environmental variables (wind, river discharge, and tidal current) was analysed. Zone 1, located on the GoC continental shelf, was characterised by a seasonal variability weakened by the influence of other environmental variables. Meanwhile, Zone 2, which represented the dynamics in Cape Trafalgar but did not show any clear pattern of variability, was strongly correlated with tidal current whose variability was probably determined by other drivers.

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Tide-topography interaction along the eastern Brazilian shelf

Cited by 37 publications

References 23 publications

Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current

Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current

Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

High-Chlorophyll-Area Assessment Based on Remote Sensing Observations: The Case Study of Cape Trafalgar

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Tide-topography interaction along the eastern Brazilian shelf

Cited by 37 publications

References 23 publications

Numerical simulation of M2 internal tides in the South Brazil Bight and their interaction with the Brazil Current

Numerical simulation of M2 internal tides in the South Brazil Bight and their interaction with the Brazil Current

Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

High-Chlorophyll-Area Assessment Based on Remote Sensing Observations: The Case Study of Cape Trafalgar

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Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current

Numerical simulation of M₂ internal tides in the South Brazil Bight and their interaction with the Brazil Current