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Bi‐Directional Energy Cascades in the Pacific Ocean From Equator to Subarctic Gyre

Qiu, Bo and Nakano, Toshiya and Chen, Shuiming and Klein, Patrice (2022) Bi‐Directional Energy Cascades in the Pacific Ocean From Equator to Subarctic Gyre. Geophysical Research Letters, 49 (8). Art. No. e2022GL097713. ISSN 0094-8276. doi:10.1029/2022gl097713.

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Ocean circulation receives its energy input at basin scales while dissipates at microscopic mixing scale. How this energy is transferred across different lengthscales is of paramount importance for understanding the ocean circulation equilibration and variability. Advancement in high-resolution numerical simulations in recent years has significantly improved our understanding of kinetic energy (KE) cascades from basin to kilometer scales, although observational evidence to verify the simulated processes remains limited. Using repeat ship-board velocity measurements along 165°E across the equatorial, subtropical and subarctic Pacific Ocean, we show that the length scale separating the inverse and forward cascades, L_S, falls in the 8 ∼ 300 km range and it does not scale straightforwardly with the baroclinic deformation radius. Balanced and unbalanced oceanic motions co-exist in this range but contribute oppositely to the directional energy cascades. L_S is observed to depend on the relative strengths of these motions, as well as by their interaction.

Item Type:Article
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URLURL TypeDescription Information ItemEddy kinetic energy data ItemJapan Meterological Agency
Qiu, Bo0000-0003-3841-6450
Nakano, Toshiya0000-0003-1846-907X
Chen, Shuiming0000-0003-1122-2517
Klein, Patrice0000-0002-3089-3896
Additional Information:© 2022. American Geophysical Union. Issue Online: 22 April 2022; Version of Record online: 22 April 2022; Accepted manuscript online: 18 April 2022; Manuscript accepted: 14 April 2022; Manuscript revised: 25 March 2022; Manuscript received: 01 January 2022. We are grateful to the past and present captains and crews of R/V Ryofu Maru and Keifu Maru, and staff of the Marine Division, JMA, for their long-term observational efforts. We also thank Rob Scott and an anonymous reviewer for their constructive comments that have helped to improve an early version of the manuscript. B. Qiu. and S. Chen acknowledge support from NASA OSTST mission (NNX17AH33G and 80NSSC21K1186). P. Klein acknowledges support of CNRS (France), LabexMer (ANR-10-LABX-19-01) as well as of the NASA-CNES SWOT mission. The authors declare no conflicts of interest relevant to this study. Data Availability Statement: The eddy kinetic energy data from global surface drifter program is available at Japan meterological Agency maintains a website that includes the repeat shipboard Acoustic Doppler Current Profiler data along 165°E.
Funding AgencyGrant Number
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-10-LABX-19-01
Subject Keywords:kinetic energy inverse cascade; kinetic energy forward cascade; bi-directional kinetic energy cascade; oceanic balanced and unbalanced motions; nonlinear interaction; shipboard Acoustic Doppler Current Profiler(ADCP)
Issue or Number:8
Record Number:CaltechAUTHORS:20220517-393665000
Persistent URL:
Official Citation:Qiu, B., Nakano, T., Chen, S., & Klein, P. (2022). Bi-directional energy cascades in the Pacific Ocean from Equator to Subarctic Gyre. Geophysical Research Letters, 49, e2022GL097713.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114765
Deposited By: Tony Diaz
Deposited On:17 May 2022 17:59
Last Modified:17 May 2022 17:59

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