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Title: Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model

Abstract

High spatial resolution isopycnal diffusivities are estimated in the Kuroshio Extension (KE) region (28°–40°N, 120°–190°E) from a global 1/10° Parallel Ocean Program (POP) simulation. The numerical float tracks are binned using a clustering approach. The number of tracks in each bin is thus roughly the same leading to diffusivity estimates that converge better than those in bins defined by a regular geographic grid. Cross-stream diffusivities are elevated in the southern recirculation gyre region, near topographic obstacles and downstream in the KE jet, where the flow has weakened. Along-stream diffusivities, which are much larger than cross-stream diffusivities, correlate well with the magnitudes of eddy velocity. The KE jet suppresses cross-stream mixing only in some longitude ranges. This study estimates the critical layer depth both from linear local baroclinic instability analysis and from eddy phase speeds in the POP model using the Radon transform. The latter is a better predictor of large mixing length in the cross-stream direction. Critical layer theory is most applicable in the intense jet regions away from topography.

Authors:
 [1];  [1];  [1];  [2]
  1. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography
  2. Univ. of Hamburg (Germany)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1565243
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Oceanography
Additional Journal Information:
Journal Volume: 44; Journal Issue: 8; Journal ID: ISSN 0022-3670
Publisher:
American Meteorological Society
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Oceanography

Citation Formats

Chen, Ru, McClean, Julie L., Gille, Sarah T., and Griesel, Alexa. Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model. United States: N. p., 2014. Web. doi:10.1175/jpo-d-13-0258.1.
Chen, Ru, McClean, Julie L., Gille, Sarah T., & Griesel, Alexa. Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model. United States. doi:10.1175/jpo-d-13-0258.1.
Chen, Ru, McClean, Julie L., Gille, Sarah T., and Griesel, Alexa. Tue . "Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model". United States. doi:10.1175/jpo-d-13-0258.1. https://www.osti.gov/servlets/purl/1565243.
@article{osti_1565243,
title = {Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model},
author = {Chen, Ru and McClean, Julie L. and Gille, Sarah T. and Griesel, Alexa},
abstractNote = {High spatial resolution isopycnal diffusivities are estimated in the Kuroshio Extension (KE) region (28°–40°N, 120°–190°E) from a global 1/10° Parallel Ocean Program (POP) simulation. The numerical float tracks are binned using a clustering approach. The number of tracks in each bin is thus roughly the same leading to diffusivity estimates that converge better than those in bins defined by a regular geographic grid. Cross-stream diffusivities are elevated in the southern recirculation gyre region, near topographic obstacles and downstream in the KE jet, where the flow has weakened. Along-stream diffusivities, which are much larger than cross-stream diffusivities, correlate well with the magnitudes of eddy velocity. The KE jet suppresses cross-stream mixing only in some longitude ranges. This study estimates the critical layer depth both from linear local baroclinic instability analysis and from eddy phase speeds in the POP model using the Radon transform. The latter is a better predictor of large mixing length in the cross-stream direction. Critical layer theory is most applicable in the intense jet regions away from topography.},
doi = {10.1175/jpo-d-13-0258.1},
journal = {Journal of Physical Oceanography},
issn = {0022-3670},
number = 8,
volume = 44,
place = {United States},
year = {2014},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 16 works
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Figures / Tables:

FIG. 1 FIG. 1: Color shows the bathymetry (m) in the study domain, and black contours are streamlines averaged over the years 1994 and 1995. Streamlines are defined in Eq. (1). Blue texts denote major topographic features in this region: Izu Ridge, Shatsky Rise, Emperor Seamounts, and Hess Rise.

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Works referencing / citing this record:

Eddy stirring and horizontal diffusivity from Argo float observations: Geographic and depth variability
journal, May 2015

  • Cole, Sylvia T.; Wortham, Cimarron; Kunze, Eric
  • Geophysical Research Letters, Vol. 42, Issue 10
  • DOI: 10.1002/2015gl063827

Investigating Subsurface Pathways of Fukushima Cesium in the Northwest Pacific
journal, June 2019

  • Cedarholm, Ella R.; Rypina, Irina I.; Macdonald, Alison M.
  • Geophysical Research Letters, Vol. 46, Issue 12
  • DOI: 10.1029/2019gl082500

Eddy stirring and horizontal diffusivity from Argo float observations: Geographic and depth variability
journal, May 2015

  • Cole, Sylvia T.; Wortham, Cimarron; Kunze, Eric
  • Geophysical Research Letters, Vol. 42, Issue 10
  • DOI: 10.1002/2015gl063827

Investigating Subsurface Pathways of Fukushima Cesium in the Northwest Pacific
journal, June 2019

  • Cedarholm, Ella R.; Rypina, Irina I.; Macdonald, Alison M.
  • Geophysical Research Letters, Vol. 46, Issue 12
  • DOI: 10.1029/2019gl082500