Energetics of eddy-mean flow interactions along the western boundary currents in the North Pacific

Xiaomei Yan, Dujuan Kang, Enrique Curchitser, Chongguang Pang

Research output: Contribution to journalArticle

Abstract

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 × 108W of kinetic energy and releases 2.82 × 108W 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 × 108W of kinetic energy and 1.89 × 108W 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.

Original languageEnglish (US)
Pages (from-to)789-810
Number of pages22
JournalJournal of Physical Oceanography
Volume49
Issue number3
DOIs
StatePublished - Mar 1 2019

Fingerprint

western boundary current
eddy
energetics
kinetic energy
barotropic instability
potential energy
baroclinic instability
mesoscale eddy
flow field
drain
simulator
energy
general circulation model
spatial distribution
ocean

All Science Journal Classification (ASJC) codes

  • Oceanography

Keywords

  • Boundary currents
  • Eddies
  • Mesoscale processes
  • Ocean circulation
  • Ocean dynamics

Cite this

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title = "Energetics of eddy-mean flow interactions along the western boundary currents in the North Pacific",
abstract = "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 × 108W of kinetic energy and releases 2.82 × 108W 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 × 108W of kinetic energy and 1.89 × 108W 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 along the western boundary currents in the North Pacific. / Yan, Xiaomei; Kang, Dujuan; Curchitser, Enrique; Pang, Chongguang.

In: Journal of Physical Oceanography, Vol. 49, No. 3, 01.03.2019, p. 789-810.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Energetics of eddy-mean flow interactions along the western boundary currents in the North Pacific

AU - Yan, Xiaomei

AU - Kang, Dujuan

AU - Curchitser, Enrique

AU - Pang, Chongguang

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AB - 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 × 108W of kinetic energy and releases 2.82 × 108W 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 × 108W of kinetic energy and 1.89 × 108W 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.

KW - Boundary currents

KW - Eddies

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