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High-frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean

Su, Zhan and Torres, Hector and Klein, Patrice and Thompson, Andrew F. and Siegelman, Lia and Wang, Jinbo and Menemenlis, Dimitris and Hill, Christopher (2020) High-frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean. Journal of Geophysical Research. Oceans, 125 (9). Art. No. e2020JC016544. ISSN 2169-9275. doi:10.1029/2020JC016544.

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The rate of ocean heat uptake depends on the mechanisms that transport heat between the surface and the ocean interior. A recent study found that the vertical heat transport driven by motions with scales smaller than 0.5° (submesoscales) and frequencies smaller than 1 day⁻¹ is upward. This transport competes with the other major components of the global heat transport, namely, the downward heat transport explained by the large‐scale wind‐driven vertical circulation and vertical diffusion at small scales and the upward heat transport associated with mesoscale eddies (50‐ to 300‐km size). The contribution from motions with small spatial scales (<0.5°) and frequencies larger than 1 day⁻¹, including internal gravity waves, has never been explicitly estimated. This study investigates this high‐frequency (subdaily) submesoscale contribution to the global heat transport. The major result of this study, based on the analysis of a high‐resolution ocean model, is that including this high‐frequency contribution surprisingly doubles the upward heat transport due to submesoscales in winter in the global ocean. This contribution typically concerns depths down to 200–500 m and can have a magnitude of up to 500 W m⁻² in terms of wintertime heat fluxes at 40‐m depth, which causes a significant upward heat transport of ~7 PW when integrated over the global ocean. Thus, such submesoscale heat transport, which is not resolved by climate models, impacts the heat uptake in the global ocean. The mechanisms involved in these results still need to be understood, which should be the scope of future work.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemModel/Data
Su, Zhan0000-0002-2699-431X
Torres, Hector0000-0003-2098-8012
Klein, Patrice0000-0002-3089-3896
Thompson, Andrew F.0000-0003-0322-4811
Siegelman, Lia0000-0003-3330-082X
Wang, Jinbo0000-0001-5034-5566
Menemenlis, Dimitris0000-0001-9940-8409
Hill, Christopher0000-0003-3417-9056
Additional Information:© 2020 American Geophysical Union. Accepted manuscript online: 18 August 2020; Manuscript accepted: 13 August 2020; Manuscript revised: 06 August 2020; Manuscript received: 26 June 2020. We gratefully thank the MITgcm developers and NAS scientists who made it possible to run our global numerical simulation at high resolution, as well as Christopher Henze at NASA Ames Hyperwall for providing insightful and unique visualization capabilities. We thank Hong Zhang for the excellent technical support on conducting the numerical simulation. Z. S. was supported by NSF Award OAC‐1835618 (Collaborative Research: Framework: Data: Toward Exascale Community Ocean Circulation Modeling) and NASA Grant NNX15AG42G. P. K. is supported by the NASA‐CNES SWOT mission and a NASA Senior Fellowship. A. F. T. is supported by NASA Grants NNX15AG42G and 8ONSSCI9KIOO4. J. W. was supported by the SWOT mission and JPL President/Director Research and Development Fund. C.H. was supported by NSF Award OAC‐1835618. H.T., L.S., J.W. and D.M. carried research at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA, with support from the Physical Oceanography (PO) and Modeling, Analysis, and Prediction (MAP) Programs. Computations were carried out at the NASA Advanced Supercomputing (NAS) facilities. Data Availability Statement: The model and data used in this study can be obtained/reproduced from the MITgcm website (
Funding AgencyGrant Number
Subject Keywords:ocean heat transport; high frequency; ocean front; eddies; eddy transport
Issue or Number:9
Record Number:CaltechAUTHORS:20200820-141623994
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Official Citation:Su, Z., Torres, H., Klein, P., Thompson, A. F., Siegelman, L., Wang, J., et al. (2020). High‐frequency submesoscale motions enhance the upward vertical heat transport in the global ocean. Journal of Geophysical Research: Oceans, 125, e2020JC016544.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105046
Deposited By: Tony Diaz
Deposited On:20 Aug 2020 22:06
Last Modified:16 Nov 2021 18:39

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