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OCEAN DYNAMICS

 TEL AVIV UNIVERSITY

ABOUT ME

Confident Businessman

I am a Postdoc studying physical oceanography at the Department of atmospheric and oceanic sciences, UCLA in Jim McWilliams 's lab. My research interests are geophysical fluid dynamics, energetics of stratified turbulent flows and the interactions between mesoscales, sub-mesoscales and internal waves in the ocean. I obtained my PhD at the Scripps Institution of Oceanography, UCSD. My thesis advisors were Kraig Winters and Stefan Llewellyn Smith.

My CV

ABOUT ME

Associate Researcher

Department of Atmospheric and Oceanic Sciences.

3637 Geology Building, UCLA,

Los Angeles, California, USA

rbarkan@atmos.ucla.edu

1-310-206-9381

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Senior Lecturer (Assistant Professor)

Porter School of the Environment and Earth Sciences.

311 Kaplun Building, Tel Aviv University, Ramat Aviv, Israel

rbarkan@tauex.tau.ac.il

972-3-640-7048

I study the physics of the ocean circulation using a combination of mathematical theory, numerical models, and analysis of in situ measurements.  In particular, I am interested in the oceanic processes that determine the transfer of energy, heat, and other tracers across scales, and from the surface to the ocean interior. These processes have fundamental implications to the climate system, to  the dispersion of contaminants, and to Biology. One of my main research foci is to understand the dynamics of submesoscale currents; recently discovered flow patterns, consisting of rapidly evolving fronts, filaments, and eddies. Submesoscale currents can interact with both the larger-scale currents and eddies, and the smaller-scales internal and surface waves, thereby affecting a wide range of physical phenomena.

About
RESEARCH

RESEARCH

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Oceanic Energy Pathways

Oceanic mesoscale eddies, with spatial scales of O(100km) and time scale of O(weeks-month), are the largest reservoir of kinetic energy in the oceans.  They are considered to be balanced in the sense that their dynamics is largely constrained by the Earth's rotation and by the stratification of the oceans. As a result they are expected, according to geostrophic turbulence theory, to transfer kinetic energy to larger scales. However, observations show that the oceanic kinetic energy is dissipated at molecular scales. Some mechanism must therefore break the balanced dynamics of the mesoscale eddies, and allow kinetic energy to be transferred to smaller scales where it can be dissipated. In 7 we show how the spontaneous formation of submesoscale currents can break the balance (spontaneous imbalance), and in 9 we show how near-inertial internal waves can interact with mesoscale and submsoscale currents and stimulate the loss of balance (stimulated imbalance).

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Submesoscale Turbulence and Frontogenesis

Submesoscale turbulence consists of flow structures with spatial scales of O(100m-10km), temporal scales of O(hours-day), in a dynamical regime characterized by O(1) Rossby and Richardson numbers. Phenomenologically, the flow exhibits anisotropic patterns of lines or streaks with large magnitudes of buoyancy and velocity gradients, cyclonic vorticity and convergence (10,11,12). The associated velocity spectrum is shallow and the velocity gradient spectrum has roughly equal contributions from the divergence and vorticity spectra that comprise it. In 15 we use these dynamical, phenomenological, and spectral characteristics to develop an asymptotic theory for submesoscale turbulence. Specifically, we characterize the formation of the fronts and filaments, which we define as submesoscale frontogenesis.  We are able to validate the theory with high-resolution numerical simulations and Lagrangian in-situ measurements. Our theory has important implications to the horizontal and vertical transport of tracers in the ocean.

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Dispersion of Oil and other Contaminants

Oil spills are unfortunately common in today's world. I am actively involved in the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE), which is a team dedicated to predicting the fate of oil released into our environment. I took part in a number of field experiments and numerical studies in the Gulf of Mexico, near the site of the catastrophic DeepWater Horizon oil spill. In 11,12,13 we investigate and characterize the important role of submesoscale eddies and fronts in governing oil dispersion in the region.  

Eddy-Inertial Wave Interaction

(Near) Inertial Waves (NIWs) are internal waves most typically excited by high frequency wind variability (e.g., storms). The mechanisms by which the excited NIWs propagate into the ocean interior, reduce in size, break, and vertically mix properties remain poorly understood. Possible mechanisms include the interactions with the coexisting mesoscale eddies and submesoscale currents.  In 9 we demonstrate that as NIWs propagate through a field of fronts and eddies they scatter into smaller scales while actively exchanging energy. These interactions are found crucial to match observed energy spectra at sub- and super-inertial frequencies, and to enhance the forward cascade of mesoscale energy to dissipation. 

PUBLICATIONS

PUBLICATIONS

IN PROGRESS / SUBMITTED

  • Shaham, M., and Barkan, R. (2024). Spectral Flux Decomposition in Turbulent Channel Flow with Near-Inertial Waves. Journal of Advances in Modeling Earth Systems. 

  • Fadida Y., and Verma, V., and Barkan, R, and Biton Eli., and Solodoch, A., and Lehahn Y. (2024). Submesoscale horizontal stirring enhances seasonal enrichment of low-chlorophyll surface waters. PNAS.

  • Siyanbola, O.Q, Buijsman, M.C., Delpech, A., Barkan, R., Pan Yulin, and Arbic, B.K. (2024). Interactions of Remotely Generated Internal Tides with the U.S. West Coast Continental Margin. Journal of Geophysical Research: Oceans.

  • Verma, V., and Barkan, R., and Solodoch, A., and Gildor, H., and Toledo, Y. (2024). The eastern Mediterranean boundary current: seasonality, stability, and spiral formation. Journal of Physical Oceanography.

IN PRESS / PUBLISHED

  • Delpech, A., Barkan, R., Srinivasan, K., McWilliams, J. C., Arbic, B.K., Siyanbola, O.Q., and Buijsman, M.C. (2023) .Eddy - Internal Wave Interactions and their Contribution to Cross-Scale Energy Fluxes: a case study in the California Current. Journal of Physical Oceanography. DOI: https://doi.org/10.1175/JPO-D-23-0181.1. LINK

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  • Yang, L., Barkan, R., Srinivasan, K., McWilliams, J. C., Shakespear, C. J., and Gibson, A. H. (2023). Oceanic eddies induce a rapid formation of an internal wave continuum. . Nature Comm. Earth and Environment. 4(1), 484. LINK 

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  • Barkan, R., Srinivasan, K., and McWilliams, J. C. (2024). Eddy - Internal Wave Interactions: Stimulated Cascades in Cross-scale Kinetic Energy and Enstrophy Fluxes. Journal of Physical Oceanography. LINK 

  • Miguel S. Solano, Maarten C. Buijsman, Jay F. Shriver, Jorge Magalhaes, Jose da Silva, Christo- pher Jackson, Brian K. Arbic, and Roy Barkan. (2023). Nonlinear internal tides in a real- istically forced global ocean simulation. Journal of Geophysical Research: Oceans. 128(12), e2023JC019913. LINK

27

  • Solodoch, A. and Barkan, R. and Verma, V. and Gildor, H. and Toledo, Y. and Khain, P. and Levi, Y. (2023). Basin Scale to Submesoscale Variability of the East-Mediterranean Sea Upper Circulation. Journal of Physical Oceanography. 53, 2137-2158. LINK

26

  • Wang, T., Barkan, R., McWilliams, J. C., & Molemaker, M. J. (2021). Structure of submesoscale fronts of the Mississippi River plume. Journal of Physical Oceanography, 51(4), 1113-1131. LINK

19

  • Callies, J., Barkan, R., and Garabato, A. N. (2020). Time Scales of Submesoscale Flow Inferred from a Mooring Array. Journal of Physical Oceanography, 50(4), 1065-1086. LINK

18

  • Bracco, A., and Daoxun, and R. Barkan, and M. Berta, and D. Dauhare, and MJ Molemaker, J. Choi, and Guanpeng, and A. Berta, and J. C. McWilliams, 2020. Diurnal Cycling of Submesoscale Dynamics: Lagrangian Implications in drifter observations and model simulations of the northern gulf of mexico. J. Phys. Oceanogr. 50, 1605-1623. LINK

17

  • Naveira Garabato, A.C., Yu, X, Callies, J., Barkan R., Polzin, K.L., and Frajka-Williams, E.E. (2022). Kinetic energy transfers between mesoscale and submesoscale motions in the open ocean's upper layers.  Journal of Physical Oceanography, 52, 75-97LINK 

  • Barkan R., Srinivasan, K., Yang, L, McWilliams, J.C., Gula, J., and Vic, C. (2021) Oceanic mesoscale eddy depletion catalyzed by internal waves. Geopysical Research Letters, 48(18), e2021GL094376. LINK 

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  • Srinivasan K, Barkan, R., and McWilliams J. C. (2023). A forward energy cascade at subme- soscales driven by frontogenesis. Journal of Physical Oceanography 53, 287-305.  LINK

  • Siyanbola, O. Q., Buijsman M. C., Delpech A., Renault L., Barkan R., Shriver J. F., Arbic B. K., McWilliams J. C. (2023). Remote internal wave forcing of regional ocean simulations near the U.S. West Coast. Ocean Modelling. 181, 102-154. LINK

23

  • Delpech, A., Barkan, R., Renault, L., McWilliams, J., Siyanbola, O.Q., Buijsman, M.C. and Arbic, B.K., (2023). Wind-current feedback is an energy sink for oceanic internal waves. Scientific Reports, 13, 5915. LINK

24

  • Kar, S. and Barkan R. (2023). Energy exchanges between a two-dimensional front and internal wave modes. Journal of Physical Oceanography. 53, 2537-2557. LINK

25

  • Barkan, R., and J. C. McWilliams, and K. Srinivasan, and M. J. Molemaker, and E. A. D'Asaro. 2019. The Role of Horizontal Divergence in Submesoscale Frontogenesis. J. Phys. Oceanogr. 49, 1593-1618. LINK

16

  • Palmer, J., and B. Fox-Kemper, and R. Barkan, and J. Choi, and A. Bracco, and J. C. McWilliams. 2019. Impacts of convergence on Lagrangian statistics in the Gulf of Mexico. J. Phys. Oceanogr. 47, 2361. LINK

15

  • Srinivasan, K., and J. C. McWilliams, and M. J. Molemaker, and R. Barkan. 2019. Submesoscale Vortical Wakes in the Lee of Topography. J. Phys. Oceanogr. 49, 1949-1971      LINK

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13

  • D’Asaro, E. A., and A. Y. Shcherbina, and J. M. Klymak, and M. J. Molemaker, and G. Novelli, and C. M. Guigand, and A. C. Haza, and B. K. Haus, and E. H. Ryan, and G. A. Jacobs, and H. S. Huntley, and N. J. M. Laxague, and S. Chen, and F. Judt, and J. C. McWilliams, and R. Barkan, and A. D. Kirwan, and A. C. Poje, and T. M. Özgökmen, 2018. Ocean convergence and the dispersion of flotsam. Proc. Nat. Academy Sci., 201718453 LINK

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  • Barkan, R  and J. C. McWilliams, and A. F. Shchepetkin, and M. J. Molemaker, and L. Renault, and A. Bracco, and J. Choi. 2017. Submesoscale Dynamics in the Northern Gulf of Mexico. Part I: Regional and Seasonal Characterization, and the Role of River Outflow. J. Phys. Oceanogr. 47, 2325-2346LINK

11

  • Barkan, R and J. C. McWilliams, and A. F. Shchepetkin, and M. J. Molemaker, and K. Srinivasan, and A. Bracco, and J. Choi . 2017. Submesoscale Dynamics in the Northern Gulf of Mexico. Part II: Temperature-Salinity Compensation, and Cross Shelf Transport Processes. J. Phys. Oceangr. 47, 2347-2360. LINK

10

  • Choi. J., and A. Bracco, and R. Barkan, and J. C. McWilliams. 2017. Submesoscale Dynamics in the Northern Gulf of Mexico. Part III: Lagrangian Implications. J. Phys. Oceangr. 47, 2361-2376. LINK

09

  • Barkan, R., Winters, K.B. and McWilliams, J.C. 2017. Stimulated Imbalance and the  Enhancement of Eddy Kinetic Energy Dissipation by Internal Waves. J. Phys. Oceangr. 47, 181-198. LINK

  • Pratt, L., and R. Barkan, and I. Rypina. 2016. Scalar flux kinematics. Fluids. 1.3: 27. LINK

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07

  • Barkan, R., Winters, K.B. and Lewellyn-Smith, S.G. 2015. Energy Cascades and Loss of Balance in a Re-entrant Channel Forced by Wind Stress and Buoyancy Fluxes. J. Phys. Oceangr. 45, 272-293. LINK

06

  • Barkan, R., Winters, K.B. and Lewellyn-Smith, S.G. 2013. Rotating Horizontal Convection. J. Fluid Mech. 723, 556-586. LINK

  • Barkan, R., and ten Brink, U. 2010. Tsunami simulations of the 1867 Virgin Islands earthquake: Constraints on epicenter location and fault parameters. Bulletin of Seismological Society of America. 100, 995-1009. LINK

04

  • Winters, K. B. and Barkan, R. 2013. Available potential energy density for Boussinesq fluid flow. J. Fluid Mech. 714, 476-488. LINK

05

  • ten Brink, U., Barkan, R., Andrews, B.D., and Chaytor, J.D. 2009. Size distribution and failure initiation of submarine landslides and subaerial landslides. Earth and Planetary Science Letts. 287, 31-42LINK

02

  • Zvuloni, A., Artzy, Y.,Stone, L., Kramarsky, E., Barkan, R., Kushmaro, A., Loya, Y. 2009. Spatio- Temporal transmission patterns of Black-Band Disease in a coral community. PLoSONE 4, 1-10. LINK

03

  • Barkan, R. , ten Brink, U., and Lin, J. 2009. Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the U.S East Coast and the Caribbean. J. Marine Geology. 264, 109-122. LINK

01

PEOPLE

Group

Luwei Yang - postdoctoral researcher (UCLA)

Michal Shaham - MSc. student (TAU)

Subhajit Kar- Ph. D Student (TAU)

Audrey Delpech - postdoctoral researcher (UCLA)

Vicky Verma - postdoctoral researcher (TAU)

I am looking for graduate students and postdocs, please contact me if interested

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