Energetics of eddy‐mean flow interactions in the <scp>B</scp>razil current between 20°<scp>S</scp> and 36°<scp>S</scp>

Magalhães, Flávio de Castro; Azevedo, José Luiz Lima de; Oliveira, Leopoldo Rota de

doi:10.1002/2016jc012609

Cited by 27 publications

(29 citation statements)

References 71 publications

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“…In the southern hemisphere, the Brazil Current is baroclinically unstable (Brum et al, 2017;Magalhães et al, 2017), whereas barotropic instability is the primary energy conversion term in the Agulhas Current (Elipot & Beal, 2015;Zhu et al, 2018). Despite the EAC jet having a weaker mean flow and transport, the energetic eddy field is comparable with the other large WBCs (Rykova et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Dynamics of Interannual Eddy Kinetic Energy Modulations in a Western Boundary Current

Roughan

Kerry

2021

Geophysical Research Letters

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Among Western Boundary Currents, the East Australian Current (EAC) has a more energetic eddy field relative to its mean flow, however, the relationship between upstream transport and downstream eddy kinetic energy (EKE) is still unclear. We investigate the modulation of downstream EKE in the EAC's typical separation region (Tasman EKE Box) (33.normal1°S–36.normal6°S) based on a long‐term (22‐year), high‐resolution (2.5–6 km) model simulation and satellite altimeter observations from 1994 to 2016. Our results show that the poleward EAC transport at normal28°S leads the EKE in the Tasman EKE Box by 93–118 days. Barotropic instabilities are the primary source of EKE, and they control EKE variability in the EAC system. Anticyclonic eddies shed from the EAC dominate from normal33°S–normal36°S during high‐EKE periods, but in low‐EKE periods anticyclonic eddies penetrate even further south by ∼0.25emnormal2°.

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Section: Discussionmentioning

confidence: 99%

Dynamics of Interannual Eddy Kinetic Energy Modulations in a Western Boundary Current

Roughan

Kerry

2021

Geophysical Research Letters

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“…Existing studies of the BC-IWBC system energetics focused on regions south of the VTR, restricted either to Cape São Tomé and Cape Frio (e.g., Mano et al 2009) or to southeast Brazil (e.g., Oliveira et al 2009;Magalhães et al 2017). Those studies showed that baroclinic conversions account for most of the eddy generation, though barotropic conversions may be important in some regions.…”

Section: B Energy Conversionsmentioning

confidence: 99%

On the Steadiness and Instability of the Intermediate Western Boundary Current between 24° and 18°S

Napolitano

Silveira

Rocha

et al. 2019

Journal of Physical Oceanography

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The Intermediate Western Boundary Current (IWBC) transports Antarctic Intermediate Water across the Vitória–Trindade Ridge (VTR), a seamount chain at ~20°S off Brazil. Recent studies suggest that the IWBC develops a strong cyclonic recirculation in Tubarão Bight, upstream of the VTR, with weak time dependency. We herein use new quasi-synoptic observations, data from the Argo array, and a regional numerical model to describe the structure and variability of the IWBC and to investigate its dynamics. Both shipboard acoustic Doppler current profiler (ADCP) data and trajectories of Argo floats confirm the existence of the IWBC recirculation, which is also captured by our Regional Oceanic Modeling System (ROMS) simulation. An “intermediate-layer” quasigeostrophic (QG) model indicates that the ROMS time-mean flow is a good proxy for the IWBC steady state, as revealed by largely parallel isolines of streamfunction [Formula: see text] and potential vorticity [Formula: see text]; a [Formula: see text] scatter diagram also shows that the IWBC is potentially unstable. Further analysis of the ROMS simulation reveals that remotely generated, westward-propagating nonlinear eddies are the main source of variability in the region. These eddies enter the domain through the Tubarão Bight eastern edge and strongly interact with the IWBC. As they are advected downstream and negotiate the local topography, the eddies grow explosively through horizontal shear production.

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“…Energetics analysis is an effective method for investigating the current variability by quantifying the energy exchange between the mean and eddy reservoirs. It has been successfully applied in the Gulf Stream (Kang and Curchitser 2015, hereafter KC15), the Brazil Current (Brum et al 2017;Magalhães et al 2017), the Red Sea (Zhan et al 2016), the STCC region (Chang and Oey 2014), the Kuroshio Extension Liang 2016, 2018), and even the global ocean (Chen et al 2014(Chen et al , 2016Von Storch et al 2012). All these studies are based on numerical simulations due to the limited spatial and temporal coverage of oceanic data.…”

Section: Introductionmentioning

confidence: 99%

Energetics of Eddy–Mean Flow Interactions along the Western Boundary Currents in the North Pacific

Yan

Kang

Curchitser

et al. 2019

Journal of Physical Oceanography

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The energetics of eddy–mean flow interactions along two western boundary currents of the North Pacific, the Kuroshio and Ryukyu Currents, are systematically investigated using 22 years of numerical data from the Ocean General Circulation Model for the Earth Simulator (OFES). For the time-mean and time-varying flow fields, all the energy components and conversions exhibit inhomogeneous spatial distributions. In the two currents, complex cross-stream and along-stream variations are seen in the eddy–mean flow energy conversions. East of Taiwan, the kinetic energy is mainly transferred from the mean flow to the eddy field through barotropic instability, whereas the baroclinic energy conversions form a meridional dipole structure caused by the topographic constraint. In the northern area, particularly, the eddy field drains 2.25 × 108 W of kinetic energy and releases 2.82 × 108 W of available potential energy when interacting with the mean flow, indicating that mesoscale eddies impinging on the Kuroshio decay with baroclinic inverse energy cascades. In the Ryukyu Current, inverse energy conversions from the eddy field to the mean flow also dominate the power transfer in the subsurface layer. The eddy field transfers 0.16 × 108 W of kinetic energy and 1.89 × 108 W of available potential energy to the mean flow, suggesting that meososcale eddies play an important role in maintaining the velocity and hydrographic structure of the current. In other areas, both barotropic and baroclinic instabilities contribute to the generation of eddy kinetic energy with the latter one providing more than 3 times as much power as the former one.

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Energetics of eddy‐mean flow interactions in the Brazil current between 20°S and 36°S

Cited by 27 publications

References 71 publications

Dynamics of Interannual Eddy Kinetic Energy Modulations in a Western Boundary Current

Dynamics of Interannual Eddy Kinetic Energy Modulations in a Western Boundary Current

On the Steadiness and Instability of the Intermediate Western Boundary Current between 24° and 18°S

Energetics of Eddy–Mean Flow Interactions along the Western Boundary Currents in the North Pacific

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