On the baroclinic structure of the Brazil Current–Intermediate Western Boundary Current system at 22°–23°S

2004 ◽  
Vol 31 (14) ◽  
Author(s):  
I. C. A. da Silveira
Keyword(s):  
Current System ◽  
Western Boundary Current ◽  
Western Boundary ◽  
Boundary Current ◽  
Brazil Current

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

2009 ◽  
Vol 29 (2) ◽  
pp. 154-158 ◽  
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

scholarly journals The INALT family – a set of high-resolution nests for the Agulhas Current system within global NEMO ocean/sea-ice configurations

2019 ◽  
Vol 12 (7) ◽  
pp. 3329-3355 ◽  
Author(s):  
Franziska U. Schwarzkopf ◽  
Arne Biastoch ◽  
Claus W. Böning ◽  
Jérôme Chanut ◽  
Jonathan V. Durgadoo ◽  
...  
Keyword(s):  
High Resolution ◽  
Boundary Conditions ◽  
Current System ◽  
Western Boundary Current ◽  
Global Ocean ◽  
Western Boundary ◽  
Boundary Current ◽  
The South ◽  
Agulhas Current ◽  
Mesoscale Dynamics

Abstract. The Agulhas Current, the western boundary current of the South Indian Ocean, has been shown to play an important role in the connectivity between the Indian and Atlantic oceans. The greater Agulhas Current system is highly dominated by mesoscale dynamics. To investigate their influence on the regional and global circulations, a family of high-resolution ocean general circulation model configurations based on the NEMO code has been developed. Horizontal resolution refinement is achieved by embedding “nests” covering the South Atlantic and the western Indian oceans at 1/10∘ (INALT10) and 1/20∘ (INALT20) within global hosts with coarser resolutions. Nests and hosts are connected through two-way interaction, allowing the nests not only to receive boundary conditions from their respective host but also to feed back the impact of regional dynamics onto the global ocean. A double-nested configuration at 1/60∘ resolution (INALT60) has been developed to gain insights into submesoscale processes within the Agulhas Current system. Large-scale measures such as the Drake Passage transport and the strength of the Atlantic meridional overturning circulation are rather robust among the different configurations, indicating the important role of the hosts in providing a consistent embedment of the regionally refined grids into the global circulation. The dynamics of the Agulhas Current system strongly depend on the representation of mesoscale processes. Both the southward-flowing Agulhas Current and the northward-flowing Agulhas Undercurrent increase in strength with increasing resolution towards more realistic values, which suggests the importance of improving mesoscale dynamics as well as bathymetric slopes along this narrow western boundary current regime. The exploration of numerical choices such as lateral boundary conditions and details of the implementation of surface wind stress forcing demonstrates the range of solutions within any given configuration.

scholarly journals Weak Thermocline Mixing in the North Pacific Low-Latitude Western Boundary Current System

2017 ◽  
Vol 44 (20) ◽  
pp. 10,530-10,539 ◽  
Author(s):  
Zhiyu Liu ◽  
Qiang Lian ◽  
Fangtao Zhang ◽  
Lei Wang ◽  
Mingming Li ◽  
...  
Keyword(s):  
North Pacific ◽  
Current System ◽  
Western Boundary Current ◽  
Western Boundary ◽  
Boundary Current ◽  
Low Latitude ◽  
The North ◽  
The North Pacific

Directional Extreme Current Profiles Based on Complex Empirical Orthogonal Functions (C-EOF) for Offshore Design

2009 ◽  
Author(s):  
Jose Antonio Moreira Lima ◽  
Eric Oliveira Ribeiro ◽  
Wellington Ceccopieri ◽  
Guisela Grossmann Matheson
Keyword(s):  
Goodness Of Fit ◽  
Structural Reliability ◽  
Current System ◽  
Correlation Coefficients ◽  
Current Data ◽  
Empirical Orthogonal Functions ◽  
Western Boundary ◽  
Boundary Current ◽  
Orthogonal Functions ◽  
Brazil Current

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.

scholarly journals Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

Ocean Science ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Till Jens Jörg Hanebuth ◽  
Renata Hanae Nagai ◽  
Marcia Caruso Bícego ◽  
Rubens Cesar Lopes Figueira ◽  
...  
Keyword(s):  
Organic Matter ◽  
Molecular Markers ◽  
Ocean Circulation ◽  
Western Boundary Current ◽  
Western Boundary ◽  
Boundary Current ◽  
Geochemical Fingerprinting ◽  
Brazil Current ◽  
Shelf Sediments ◽  
Upper Slope

Abstract. In this study, we use inorganic (metal) and organic (bulk and molecular) markers in sediment samples of the south-eastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply.Metal contents and especially the ln(Ti ∕ Al) and ln(Fe ∕ K) ratios make it possible to recognise the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K ∕ Sc) and ln(K ∕ Al) ratios used as proxies of illite–kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.

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

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.

scholarly journals Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

2016 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Till Jens Jörg Hanebuth ◽  
Renata Hanae Nagai ◽  
Marcia Caruso Bícego ◽  
Rubens Cesar Lopes Figueira ◽  
...  
Keyword(s):  
Organic Matter ◽  
Molecular Markers ◽  
Ocean Circulation ◽  
Western Boundary Current ◽  
Western Boundary ◽  
Boundary Current ◽  
Geochemical Fingerprinting ◽  
Brazil Current ◽  
Shelf Sediments ◽  
Upper Slope

Abstract. In this study, we use inorganic (metals) and organic (bulk and molecular) markers in sediment samples of the southeastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply. Metal contents and especially the ln(Ti/Al) and ln(Fe/K) ratios make it possible to recognize the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K/Sc) and ln(K/Al) ratios used as proxies of illite–kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.

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