U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Understanding Current and Eddy Contributions to Ocean Mixing
Published: July 13, 2017
Posted: January 26, 2018

Mixing is dominated by mean and eddy flow interactions; new mixing parameterizations are needed.

The Science
Ocean gyres and currents in the ocean interact to transport carbon and heat into the deep ocean. A simplified and idealized Antarctic Circumpolar Current flow is analyzed to understand what causes mixing by identifying mixing contributions by gyres, currents, and their interactions.

The Impact
Combined mixing by ocean gyres and currents dominate ocean mixing, suggesting that high resolution is necessary to compute the correct transport of carbon and heat into the deep ocean. Modifications are needed to existing mixing models using mixing suppression and critical layer theory; our diagnosed vertical variability and gyre-current interactions are key for improvement.

Transport of heat and carbon into the ocean from the atmosphere and melting of ice sheets by ocean flows is largely mediated by ocean mixing, quantified with a diffusivity. We diagnose mixing in an Idealized Circumpolar Current that approximates the Antarctic Circumpolar Current and Antarctic shelf break. We measure a reduced diffusivity over the shelf break, which is a mechanism that helps inhibit on-shelf mixing of ocean water with ice sheet cavities to help constrain the rate of land ice melting. Mixing is produced by the combined action of ocean gyres and currents, e.g., large eddies and the mean flow. We decompose the full diffusivity into its key mixing contributions by the eddy, mean, and residual (combined eddy-mean) flows. Results indicate that mixing is largely produced by interactions of the mean and eddy flows. Eddy and mean contributions are small as compared with the nonlinear residual. The diffusivity decomposition provides a path for improved understanding of ocean mixing. The importance of residual contributions of eddy-mean interactions indicates high resolution is key to resolving mixing. We find that existing diffusivity models require new and improved parameterization strategies.

Contacts (BER PM)
Dorothy Koch
Earth System Modeling Program

(PI Contact)
Phillip J. Wolfram
Los Alamos National Laboratory

The U.S. Department of Energy Office of Science, Biological and Environmental Research supported this research as part of the Accelerated Climate Modeling for Energy (ACME) project of the Earth System Modeling (ESM) program.

Wolfram, P., T.D. Ringler. "Quantifying Residual, Eddy, and Mean Flow Effects on Mixing in an Idealized Circumpolar Current." Journal of Physical Oceanography 47, 1897-1920 (2017). [DOI:10.1175/JPO-D-16-0101.1].
(Reference link)

Related Links
BER Highlight: Understanding Current and Eddy Contributions to Ocean Mixing

Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling

Division: SC-23.1 Climate and Environmental Sciences Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)