• Abernathey, R., and G. Haller, 2018: Transport by Lagrangian vortices in the eastern Pacific. J. Phys. Oceanogr., 48, 667685, https://doi.org/10.1175/JPO-D-17-0102.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Abernathey, R. P., and J. Marshall, 2013: Global surface eddy diffusivities derived from satellite altimetry. J. Geophys. Res. Oceans, 118, 901916, https://doi.org/10.1002/jgrc.20066.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Beron-Vera, F. J., Y. Wang, M. J. Olascoaga, G. Goni, and G. Haller, 2013: Objective detection of oceanic eddies and the Agulhas leakage. J. Phys. Oceanogr., 43, 14261438, https://doi.org/10.1175/JPO-D-12-0171.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brannigan, L., D. P. Marshall, A. Naveira-Garabato, and A. J. George Nurser, 2015: The seasonal cycle of submesoscale flows. Ocean Modell., 92, 6984, https://doi.org/10.1016/j.ocemod.2015.05.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chaigneau, A., M. L. Texier, G. Eldin, C. Grados, and O. Pizarro, 2011: Vertical structure of mesoscale eddies in the eastern south Pacific ocean: A composite analysis from altimetry and Argo profiling floats. J. Geophys. Res., 116, C11025, https://doi.org/10.1029/2011JC007134.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chassignet, E. P., and B. Cushman-Roisin, 1991: On the influence of a lower layer on the propagation of nonlinear oceanic eddies. J. Phys. Oceanogr., 21, 939957, https://doi.org/10.1175/1520-0485(1991)021<0939:OTIOAL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chelton, D. B., M. G. Schlax, R. M. Samelson, and R. A. De Szoeke, 2007: Global observations of large oceanic eddies. Geophys. Res. Lett., 34, L15606, https://doi.org/10.1029/2007GL030812.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chelton, D. B., M. G. Schlax, and R. M. Samelson, 2011: Global observations of nonlinear mesoscale eddies. Prog. Oceanogr., 91, 167216, https://doi.org/10.1016/j.pocean.2011.01.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Constantinou, N. C., 2018: A barotropic model of eddy saturation. J. Phys. Oceanogr., 48, 397411, https://doi.org/10.1175/JPO-D-17-0182.1.

  • Conway, T. M., J. B. Palter, and G. F. de Souza, 2018: Gulf Stream rings as a source of iron to the North Atlantic subtropical gyre. Nat. Geosci., 11, 594598, https://doi.org/10.1038/s41561-018-0162-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cushman-Roisin, B., B. Tang, and E. Chassignet, 1990: Westward motion of mesoscale eddies. J. Phys. Oceanogr., 20, 758768, https://doi.org/10.1175/1520-0485(1990)020<0758:WMOME>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davis, R., 1991: Observing the general circulation with floats. Deep-Sea Res., 38A, S531S571, https://doi.org/10.1016/S0198-0149(12)80023-9.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dong, C., J. C. Mcwilliams, Y. Liu, and D. Chen, 2014: Global heat and salt transports by eddy movement. Nat. Commun., 5, 3294, https://doi.org/10.1038/ncomms4294.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Early, J. J., R. M. Samelson, and D. B. Chelton, 2011: The evolution and propagation of quasigeostrophic ocean eddies. J. Phys. Oceanogr., 41, 15351555, https://doi.org/10.1175/2011JPO4601.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Eden, C., 2007: Eddy length scales in the North Atlantic Ocean. J. Geophys. Res., 112, C06004, https://doi.org/10.1029/2006JC003901.

  • Eden, C., and R. J. Greatbatch, 2008: Towards a mesoscale eddy closure. Ocean Modell., 20, 223239, https://doi.org/10.1016/j.ocemod.2007.09.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferrari, R., and C. Wunsch, 2010: The distribution of eddy kinetic and potential energies in the global ocean. Tellus, 62A, 92108, https://doi.org/10.3402/tellusa.v62i2.15680.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grooms, I., 2015: A computational study of turbulent kinetic energy transport in barotropic turbulence on the f-plane. Phys. Fluids, 27, 101701, https://doi.org/10.1063/1.4934623.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grooms, I., 2017: Simulations of eddy kinetic energy transport in barotropic turbulence. Phys. Rev. Fluids, 2, 113801, https://doi.org/10.1103/PhysRevFluids.2.113801.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hughes, C. W., and P. I. Miller, 2017: Rapid water transport by long-lasting modon eddy pairs in the southern midlatitude oceans. Geophys. Res. Lett., 44, 12 37512 384, https://doi.org/10.1002/2017GL075198.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jansen, M. F., and I. M. Held, 2014: Parameterizing subgrid-scale eddy effects using energetically consistent backscatter. Ocean Modell., 80, 3648, https://doi.org/10.1016/j.ocemod.2014.06.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jansen, M. F., A. J. Adcroft, R. Hallberg, and I. M. Held, 2015: Parameterization of eddy fluxes based on a mesoscale energy budget. Ocean Modell., 92, 2841, https://doi.org/10.1016/j.ocemod.2015.05.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klocker, A., and R. Abernathey, 2014: Global patterns of mesoscale eddy properties and diffusivities. J. Phys. Oceanogr., 44, 10301046, https://doi.org/10.1175/JPO-D-13-0159.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klocker, A., and D. P. Marshall, 2014: Advection of baroclinic eddies by depth mean flow. Geophys. Res. Lett., 41, 35173521, https://doi.org/10.1002/2014GL060001.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klocker, A., D. P. Marshall, S. R. Keating, and P. L. Read, 2016: A regime diagram for ocean geostrophic turbulence. Quart. J. Roy. Meteor. Soc., 142, 24112417, https://doi.org/10.1002/qj.2833.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Koszalka, I. M., A. Bracco, J. C. Mcwilliams, and A. Provenzale, 2009: Dynamics of wind-forced coherent anticyclones in the open ocean. J. Geophys. Res., 114, C08011, https://doi.org/10.1029/2009JC005388.

    • Search Google Scholar
    • Export Citation
  • LaCasce, J. H., 2008a: Statistics from Lagrangian observations. Prog. Oceanogr., 77 (1), 129, https://doi.org/10.1016/j.pocean.2008.02.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • LaCasce, J. H., 2008b: The vortex merger rate in freely decaying two-dimensional turbulence. Phys. Fluids, 20, 085102, https://doi.org/10.1063/1.2957020.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • LaCasce, J. H., R. Ferrari, R. Tulloch, D. Balwada, and K. G. Speer, 2014: Float-derived isopycnal diffusivities in the DIMES Experiment. J. Phys. Oceanogr., 44, 764780, https://doi.org/10.1175/JPO-D-13-0175.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Larichev, V. D., and J. C. Mcwilliams, 1991: Weakly decaying turbulence in an equivalent-barotropic fluid. Phys. Fluids, 3, 938950, https://doi.org/10.1063/1.857970.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mak, J., J. R. Maddison, D. P. Marshall, and D. R. Munday, 2018: Implementation of a geometrically informed and energetically constrained mesoscale eddy parameterization in an ocean circulation model. J. Phys. Oceanogr., 48, 23632382, https://doi.org/10.1175/JPO-D-18-0017.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marshall, D. P., and A. Adcroft, 2010: Parameterization of ocean eddies: Potential vorticity mixing, energetics and Arnold’s first stability theorem. Ocean Modell., 32, 188204, https://doi.org/10.1016/j.ocemod.2010.02.001.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marshall, D. P., J. R. Maddison, and P. S. Berloff, 2012: A framework for parameterizing eddy potential vorticity fluxes. J. Phys. Oceanogr., 42, 539557, https://doi.org/10.1175/JPO-D-11-048.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J., and G. Flierl, 1979: On the evolution of isolated, nonlinear vortices. J. Phys. Oceanogr., 9, 11551182, https://doi.org/10.1175/1520-0485(1979)009<1155:OTEOIN>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Morrow, R., F. Birol, D. Griffin, and J. Sudre, 2004: Divergent pathways of cyclonic and anti-cyclonic ocean eddies. Geophys. Res. Lett., 31, L24311, https://doi.org/10.1029/2004GL020974.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Penven, P., V. Echevin, J. Pasapera, F. Colas, and J. Tam, 2005: Average circulation, seasonal cycle, and mesoscale dynamics of the Peru current system: A modeling approach. J. Geophys. Res., 110, C10021, https://doi.org/10.1029/2005JC002945.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rhines, P. B., 1975: Waves and turbulence on a beta-plane. J. Fluid Mech., 69, 417443, https://doi.org/10.1017/S0022112075001504.

  • Richardson, P. L., 1983: Eddy kinetic energy in the north Atlantic from surface drifters. J. Geophys. Res., 88, 43554367, https://doi.org/10.1029/JC088iC07p04355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Roach, C. J., D. Balwada, and K. G. Speer, 2016: Horizontal mixing in the Southern Ocean from Argo float trajectories. J. Geophys. Res. Oceans, 121, 55705586, https://doi.org/10.1002/2015JC011440.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Roach, C. J., D. Balwada, and K. G. Speer, 2018: Global observations of horizontal mixing from Argo float and surface drifter trajectories. J. Geophys. Res.Oceans, 123, 45604575, https://doi.org/10.1029/2018JC013750.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Samelson, R. M., M. G. Schlax, and D. B. Chelton, 2016: A linear stochastic field model of midlatitude mesoscale variability. J. Phys. Oceanogr., 46, 31033120, https://doi.org/10.1175/JPO-D-16-0060.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Samelson, R. M., D. B. Chelton, and M. G. Schlax, 2019: The ocean mesoscale regime of the reduced-gravity quasigeostrophic model. J. Phys. Oceanogr., 49, 24692498, https://doi.org/10.1175/JPO-D-18-0260.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Souza, J. M. A. C., C. de Boyer Montégut, C. Cabanes, and P. Klein, 2011: Estimation of the Agulhas ring impacts on meridional heat fluxes and transport using ARGO floats and satellite data. Geophys. Res. Lett., 38, L21602, https://doi.org/10.1029/2011GL049359.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Theiss, J., 2004: Equatorward energy cascade, critical latitude, and the predominance of cyclonic vortices in geostrophic turbulence. J. Phys. Oceanogr., 34, 16631678, https://doi.org/10.1175/1520-0485(2004)034<1663:EECCLA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tulloch, R., J. Marshall, and K. S. Smith, 2009: Interpretation of the propagation of surface altimetric observations in terms of planetary waves and geostrophic turbulence. J. Geophys. Res., 114, C02005, https://doi.org/10.1029/2008JC005055.

    • Search Google Scholar
    • Export Citation
  • Xu, C., X. Zhai, and X. Shang, 2016: Work done by atmospheric winds on mesoscale ocean eddies. Geophys. Res. Lett., 43, 12 17412 180, https://doi.org/10.1002/2016GL071275.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhai, X., H. L. Johnson, and D. P. Marshall, 2010: Significant sink of ocean-eddy energy near western boundaries. Nat. Geosci., 3, 608612, https://doi.org/10.1038/ngeo943.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, Z., W. Wang, and B. Qiu, 2014: Oceanic mass transport by mesoscale eddies. Science, 345, 322324, https://doi.org/10.1126/science.1252418.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 137 137 52
Full Text Views 36 36 19
PDF Downloads 49 49 21

Random Movement of Mesoscale Eddies in the Global Ocean

View More View Less
  • 1 College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
  • 2 Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
  • 3 Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences, Fudan University, Shanghai, China
  • 4 Department of Physics, University of Oxford, Oxford, United Kingdom
© Get Permissions
Restricted access

Abstract

In this study we track and analyze eddy movement in the global ocean using 20 years of altimeter data and show that, in addition to the well-known westward propagation and slight polarity-based meridional deflections, mesoscale eddies also move randomly in all directions at all latitudes as a result of eddy–eddy interaction. The speed of this random eddy movement decreases with latitude and equals the baroclinic Rossby wave speed at about 25° of latitude. The tracked eddies are on average isotropic at mid- and high latitudes, but become noticeably more elongated in the zonal direction at low latitudes. Our analyses suggest a critical latitude of approximately 25° that separates the global ocean into a low-latitude anisotropic wavelike regime and a high-latitude isotropic turbulence regime. One important consequence of random eddy movement is that it results in lateral diffusion of eddy energy. The associated eddy energy diffusivity, estimated using two different methods, is found to be a function of latitude. The zonal-mean eddy energy diffusivity varies from over 1500 m2 s−1 at low latitudes to around 500 m2 s−1 at high latitudes, but significantly larger values are found in the eddy energy hotspots at all latitudes, in excess of 5000 m2 s−1. Results from this study have important implications for recently developed energetically consistent mesoscale eddy parameterization schemes which require solving the eddy energy budget.

Corresponding author: Xiaoming Zhai, xiaoming.zhai@uea.ac.uk

Abstract

In this study we track and analyze eddy movement in the global ocean using 20 years of altimeter data and show that, in addition to the well-known westward propagation and slight polarity-based meridional deflections, mesoscale eddies also move randomly in all directions at all latitudes as a result of eddy–eddy interaction. The speed of this random eddy movement decreases with latitude and equals the baroclinic Rossby wave speed at about 25° of latitude. The tracked eddies are on average isotropic at mid- and high latitudes, but become noticeably more elongated in the zonal direction at low latitudes. Our analyses suggest a critical latitude of approximately 25° that separates the global ocean into a low-latitude anisotropic wavelike regime and a high-latitude isotropic turbulence regime. One important consequence of random eddy movement is that it results in lateral diffusion of eddy energy. The associated eddy energy diffusivity, estimated using two different methods, is found to be a function of latitude. The zonal-mean eddy energy diffusivity varies from over 1500 m2 s−1 at low latitudes to around 500 m2 s−1 at high latitudes, but significantly larger values are found in the eddy energy hotspots at all latitudes, in excess of 5000 m2 s−1. Results from this study have important implications for recently developed energetically consistent mesoscale eddy parameterization schemes which require solving the eddy energy budget.

Corresponding author: Xiaoming Zhai, xiaoming.zhai@uea.ac.uk
Save