Northward migration of Cape São Tomé rings, Brazil

Mill, Guilherme Nogueira; Costa, Victor; Lima, N. D.; Gabioux, Mariela; Guerra, Luiz Alexandre A.; Paiva, Afonso M.

doi:10.1016/j.csr.2015.06.010

Cited by 51 publications

(28 citation statements)

References 69 publications

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“…All data show a cyclonic eddy centered at 21°S with an associated sea level drop, of at least 10 cm (14 cm for AVISO data). This feature agrees with the eddies formed at Cape São Tomé (Mill et al 2015) and is related to the velocity inversion at the beginning of the AX97 reference transect in MOVAR and HYCOM data (Fig. 13e, g, i).…”

Section: Weak Eventssupporting

confidence: 73%

“…In the weak events, the high sea-level gyre is located more to the South and the Cape São Tomé ring was present in the study case in early June 2011. The formation and northward displacement of this ring was analyzed in detail in previous works (e.g., Mill et al 2015).…”

Section: Discussionmentioning

confidence: 99%

“…The AX97 transect region ( Fig. 1) is characterized by intense mesoscale activity; its variability has been linked to weather patterns in a region of great economic importance to Brazil (Mill et al 2015) and is one of the longer-term monitoring systems of the BC.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An assessment of the Brazil Current baroclinic structure and variability near 22° S in Distinct Ocean Forecasting and Analysis Systems

et al. 2016

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The Brazil Current (BC) is the Western Boundary Current of the South Atlantic subtropical gyre, the dominant dynamic feature in the South Atlantic Ocean. The importance of this current lies in that it is the main conduit of subtropical waters to higher latitudes in the South Atlantic Ocean. This study assesses the structure and variability of the BC across the nominal latitude of 22°S using data from the high-density eXpendable BathyThermograph (XBT) AX97 transect and from three numerical ocean models with data assimilation. This XBT transect was implemented in 2004 and represents one of the longer-term monitoring systems of the BC in existence. The goal of this work is to enhance the understanding of the temporal and spatial variability of the ocean dynamics in the southwestern South Atlantic Ocean by using a suite of hydrographic observations and numerical model outputs. In the present work, 37 XBT transect realizations using data collected between 2004 and 2012 are used. Daily outputs covering the same time period are evaluated from Hybrid Coordinate Ocean Model with the Navy Coupled Ocean Data Assimilation (HYCOM-NCODA) with a 1/12°horizontal resolution, and GLORYS2V3 and FOAM, both with a 1/4°horizontal resolution. These Ocean Forecasting and Analysis Systems (OFAS) are able to capture the mean observed features in the 22°S region, showing a BC core confined to the west of 39°W and an Intermediate Western Boundary Current between the depths of 200 and 800 m. However, the OFAS tend to overestimate the mean BC baroclinic volume transport across the AX97 reference transect and underestimate its variability. The OFAS show that the coastal region between the coastline and the western edge of the AX97 transect plays an important role in the mean BC total transport, contributing to up to 23 % of its value, and further that this transport is not sampled by the XBT observations with its current sampling strategy. In order to understand the variability of the BC, a statistical classification of the BC is proposed, with the identification of three different events: weak, intermediate, and strong.

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Section: Weak Eventssupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

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An assessment of the Brazil Current baroclinic structure and variability near 22° S in Distinct Ocean Forecasting and Analysis Systems

et al. 2016

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“…Recent molecular-based analyses revealed the occurrence of numerous cryptic species in this group (Cohen et al 2004, Guillemin et al 2008, Destombe et al 2010, Lyra et al 2016. The difficulty in distinguishing species also explains the current debate about the classification of the PHYLOGEOGRAPHY OF GRACILARIA CAUDATA Gracilariales (see Gurgel et al 2018, Iha et al 2018 Santos et al (2006), Arruda et al (2013), Mill et al (2015 and Peluso et al (2018). Dotted and shaded areas indicate terrestrial coastal refugia and their boundaries, redrawn from the most historically stable Atlantic forest areas proposed in Carnaval and Moritz (2008).…”

mentioning

confidence: 99%

Dual influence of terrestrial and marine historical processes on the phylogeography of the Brazilian intertidal red alga Gracilaria caudata

Ayres-Ostrock

Valéro

Mauger

et al. 2019

Journal of Phycology

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In this study, we explored how past terrestrial and marine climate changes have interacted to shape the phylogeographic patterns of the intertidal red seaweed Gracilaria caudata, an economically important species exploited for agar production in the Brazilian north‐east. Seven sites were sampled along the north‐east tropical and south‐east sub‐tropical Brazilian coast. The genetic diversity and structure of G. caudata was inferred using a combination of mitochondrial (COI and cox2‐3), chloroplast (rbcL) and 15 nuclear microsatellite markers. A remarkable congruence between nuclear, mitochondrial and chloroplast data revealed clear separation between the north‐east (from 03° S to 08° S) and the south‐east (from 20° S to 23° S) coast of Brazil. These two clades differ in their demographic histories, with signatures of recent demographic expansions in the north‐east and divergent populations in the south‐east, suggesting the maintenance of several refugia during the last glacial maximum due to sea‐level rise and fall. The Bahia region (around 12° S) occupies an intermediate position between both clades. Microsatellites and mtDNA markers showed additional levels of genetic structure within each sampled site located south of Bahia. The separation between the two main groups in G. caudata is likely recent, probably occurring during the Quaternary glacial cycles. The genetic breaks are concordant with (i) those separating terrestrial refugia, (ii) major river outflows and (iii) frontiers between tropical and subtropical regions. Taken together with previously published eco‐physiological studies that showed differences in the physiological performance of the strains from distinct locations, these results suggest that the divergent clades in G. caudata correspond to distinct ecotypes in the process of incipient speciation and thus should be considered for the management policy of this commercially important species.

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“…C. Schmid and S. Majumder: Brazil Current transport temporarily (e.g., Schmid et al, 1995;Biló et al, 2014;Mill et al, 2015;Lima et al, 2016). As the Brazil Current reaches the confluence with the Malvinas Current, it is forced away from the shelf break and ultimately feeds into the eastward South Atlantic Current (e.g., Gordon, 1989;Garzoli, 1993;Maamaatuaiahutapu et al, 1998).…”

mentioning

confidence: 99%

Transport variability of the Brazil Current from observations and a data assimilation model

Schmid

Majumder

2018

Ocean Sci.

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Abstract. The Brazil Current transports from observations and the Hybrid Coordinate Model (HYCOM) model are analyzed to improve our understanding of the current's structure and variability. A time series of the observed transport is derived from a three-dimensional field of the velocity in the South Atlantic covering the years 1993 to 2015 (hereinafter called Argo & SSH). The mean transports of the Brazil Current increases from 3.8 ± 2.2 Sv (1 Sv is 106 m3 s−1) at 25∘ S to 13.9 ± 2.6 Sv at 32∘ S, which corresponds to a mean slope of 1.4 ± 0.4 Sv per degree. Transport estimates derived from HYCOM fields are somewhat higher (5.2 ± 2.7 and 18.7 ± 7.1 Sv at 25 and 32∘ S, respectively) than those from Argo & SSH, but these differences are small when compared with the standard deviations. Overall, the observed latitude dependence of the transport of the Brazil Current is in agreement with the wind-driven circulation in the super gyre of the subtropical South Atlantic. A mean annual cycle with highest (lowest) transports in austral summer (winter) is found to exist at selected latitudes (24, 35, and 38∘ S). The significance of this signal shrinks with increasing latitude (both in Argo & SSH and HYCOM), mainly due to mesoscale and interannual variability. Both Argo & SSH, as well as HYCOM, reveal interannual variability at 24 and 35∘ S that results in relatively large power at periods of 2 years or more in wavelet spectra. It is found that the interannual variability at 24∘ S is correlated with the South Atlantic Subtropical Dipole Mode (SASD), the Southern Annular Mode (SAM), and the Niño 3.4 index. Similarly, correlations between SAM and the Brazil Current transport are also found at 35∘ S. Further investigation of the variability reveals that the first and second mode of a coupled empirical orthogonal function of the meridional transport and the sea level pressure explain 36 and 15 % of the covariance, respectively. Overall, the results indicate that SAM, SASD, and El Niño–Southern Oscillation have an influence on the transport of the Brazil Current.

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Northward migration of Cape São Tomé rings, Brazil

Cited by 51 publications

References 69 publications

An assessment of the Brazil Current baroclinic structure and variability near 22° S in Distinct Ocean Forecasting and Analysis Systems

An assessment of the Brazil Current baroclinic structure and variability near 22° S in Distinct Ocean Forecasting and Analysis Systems

Dual influence of terrestrial and marine historical processes on the phylogeography of the Brazilian intertidal red alga Gracilaria caudata

Transport variability of the Brazil Current from observations and a data assimilation model

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