Vertical structure, energetics, and dynamics of the Brazil Current System at 22°S-28°S

This paper presents a methodology to estimate deep water design current profiles using Complex Empirical Orthogonal Function (C-EOF) and a structural reliability response based model. The advantage of C-EOF is the capability of directly obtaining directional extreme current profiles. It is estimated that most of the variability of the southeast Brazil current system can be explained by the first two EOF modes. The first mode associated with the southwestward Brazil Current (BC) and the second mode with the northeastward Intermediate Western Boundary Current (IWBC). Thus, only two series of C-EOF amplitudes can be used in the response based technique to estimate the 100-y extreme current values. The methodology can also be used with more EOF modes if required to properly represent the current data. The probabilistic cumulative functions are based on extreme value distributions such as Gumbel or Weibull, and Lognormal for conditional distributions. The evaluation of estimated distribution parameters are carried out using Kolmogorov-Smirnov goodness-of-fit hypothesis tests and correlation coefficients for each directional sector.

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Is the meander growth in the Brazil Current system off Southeast Brazil due to baroclinic instability?

Dynamics of Atmospheres and Oceans ◽

10.1016/j.dynatmoce.2008.01.002 ◽

2008 ◽

Vol 45 (3-4) ◽

pp. 187-207 ◽

Cited By ~ 68

Author(s):

I.C.A. da Silveira ◽

J.A.M. Lima ◽

A.C.K. Schmidt ◽

W. Ceccopieri ◽

A. Sartori ◽

...

Keyword(s):

Current System ◽

Baroclinic Instability ◽

Southeast Brazil ◽

Brazil Current

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Revisit the vertical structure of the eddies and eddy‐induced transport in the Leeuwin Current system

Journal of Geophysical Research Oceans ◽

10.1029/2020jc016556 ◽

2021 ◽

Author(s):

Yinghui He ◽

Ming Feng ◽

Jieshuo Xie ◽

Qingyou He ◽

Junliang Liu ◽

...

Keyword(s):

Vertical Structure ◽

Current System ◽

Leeuwin Current

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A two-layer approximation to the Brazil Current–Intermediate Western Boundary Current System between 20°S and 28°S

Ocean Modelling ◽

10.1016/j.ocemod.2009.03.008 ◽

2009 ◽

Vol 29 (2) ◽

pp. 154-158 ◽

Cited By ~ 9

Author(s):

Alexandre M. Fernandes ◽

Ilson C.A. da Silveira ◽

Leandro Calado ◽

Edmo J.D. Campos ◽

Afonso M. Paiva

Keyword(s):

Current System ◽

Western Boundary Current ◽

Western Boundary ◽

Boundary Current ◽

Brazil Current

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VARIABILIDADE DO SISTEMA CORRENTE DO BRASIL ASSOCIADA AOS CENÁRIOS DE MUDANÇAS CLIMÁTICAS A1FI E B1

Brazilian Journal of Aquatic Science and Technology ◽

10.14210/bjast.v19n3.4703 ◽

2016 ◽

Vol 19 (3) ◽

Author(s):

Carina Stefoni Böck ◽

Luiz Paulo De Freitas Assad ◽

Luiz Landau

Keyword(s):

Climate Change ◽

Heat Flux ◽

Wavelet Analysis ◽

Climate Changes ◽

Climate Model ◽

Current System ◽

Volume Transport ◽

Climate Change Scenarios ◽

Intergovernmental Panel ◽

Brazil Current

The aim of this work is to investigate the behavior of volume transport and advective heat flux patterns which are related to the Brazil Current System (BCS) according to the climate change scenarios suggested by the Intergovernmental Panel on Climate Changes. The results deriving from the global model Climate Model version 2.1 (GFDL-CM2.1) for future scenarios of climate change A1FI and B1 and for the scenario that represents the climate in the Twentieth Century (20C3M) have been used in this work. Volume transport and advective heat flux integrated for the whole BCS as well as for each water mass which constitutes the system have been calculated applying these data. Estimates were made for three zonal sections (23ºS, 25ºS and 30ºS) and then were used in the Wavelet Analysis. The performed analysis showed the occurrence of interannual variability for the estimated properties in the region. It also showed that the BCS shows changes in both intensity and variability of these parameters when comparing A1FI and B1 to 20C3M. Results from Wavelet Analysis for the total volume transport and advective heat flux integrated per section show that the period between three and six years prevails in sections 23ºS and 25ºS. The variability in 30ºS however, is significantly higher than eight years. It could also be observed the change of the variability of the total volume transport and heat flux temporal series towards higher frequencies when they are submitted to A1FI and B1 climate changes scenarios.

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A NUMERICAL STUDY OF THE BRAZILIAN SHELF/SLOPE REGION SOUTH OF 13S USING THE OCEAN MODEL ROMS

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v31i2.24 ◽

2014 ◽

Vol 31 (2) ◽

Author(s):

Janini Pereira ◽

Mauro Cirano ◽

Martinho Marta-almeida ◽

Fabiola Negreiros Amorim

Keyword(s):

Numerical Study ◽

Current System ◽

Mixed Layer Depth ◽

Ocean Model ◽

Western Boundary ◽

Boundary Current ◽

Data Set ◽

Regional Ocean Model System ◽

Brazil Current ◽

Shelf Slope

The oceanic features in the eastern and southeastern brazilian shelf/slope south of 13S is investigated using ROMS (Regional Ocean Model System). The model integration was 9 years and it was forced with: i) 6-hourly synoptic atmospheric data from NCEP; ii) initial and boundary conditions from OCCAM (Ocean Climate Circulation Advanced Modelling) monthly mean climatology and iii) tidal forcing from TPXO 7.1 global data set. The model results were compared with observations, which consisted in thermodynamic MDL (Mixed Layer Depth) climatology, satellite data, measurements from tide gauges along the shelf and currents measurements values from literature. The simulated currents represented well the BC (Brazil Current)-IWBC (IntermediateWestern Boundary Current) System. The BC - IWBC system at 22S cross-shelf section, where the mean alongshelf velocity represents our simulation capability of reproducing the western boundary currents, showed poleward BC and a opposing IWBC. At this section, the BC velocity core is in 50 m with 0.41 m.s−1 and the IWBC core around 800 m with 0.15 m.s−1.

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Evaluating two numerical advection schemes in HYCOM for eddy-resolving modelling of the Agulhas Current

Ocean Science ◽

10.5194/os-5-173-2009 ◽

2009 ◽

Vol 5 (2) ◽

pp. 173-190 ◽

Cited By ~ 18

Author(s):

B. C. Backeberg ◽

L. Bertino ◽

J. A. Johannessen

Keyword(s):

Vertical Structure ◽

Model Simulation ◽

Current System ◽

Ocean Model ◽

Sea Surface ◽

Agulhas Current ◽

Implementation Model ◽

Advection Scheme ◽

Hybrid Coordinate Ocean Model ◽

Advection Schemes

Abstract. A 4th order advection scheme is applied in a nested eddy-resolving Hybrid Coordinate Ocean Model (HYCOM) of the greater Agulhas Current system for the purpose of testing advanced numerics as a means for improving the model simulation for eventual operational implementation. Model validation techniques comparing sea surface height variations, sea level skewness and variogram analyses to satellite altimetry measurements quantify that generally the 4th order advection scheme improves the realism of the model simulation. The most striking improvement over the standard 2nd order momentum advection scheme, is that the southern Agulhas Current is simulated as a well-defined meandering current, rather than a train of successive eddies. A better vertical structure and stronger poleward transports in the Agulhas Current core contribute toward a better southwestward penetration of the current, and its temperature field, implying a stronger Indo-Atlantic inter-ocean exchange. It is found that the transport, and hence this exchange, is sensitive to the occurrences of mesoscale features originating upstream in the Mozambique Channel and southern East Madagascar Current, and that the improved HYCOM simulation is well suited for further studies of these inter-actions.

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