• Abkar, M., and P. Moin, 2017: Large-eddy simulation of thermally stratified atmospheric boundary-layer flow using a minimum dissipation model. Bound.-Layer Meteor., 165, 405419, https://doi.org/10.1007/s10546-017-0288-4.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Abkar, M., H. J. Bae, and P. Moin, 2016: Minimum-dissipation scalar transport model for large-eddy simulation of turbulent flows. Phys. Rev. Fluids, 1, 041701, https://doi.org/10.1103/PHYSREVFLUIDS.1.041701.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bachman, S. D., J. Taylor, K. Adams, and P. Hosegood, 2017: Mesoscale and submesoscale effects on mixed layer depth in the Southern Ocean. J. Phys. Oceanogr., 47, 21732188, https://doi.org/10.1175/JPO-D-17-0034.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Boccaletti, G., R. Ferrari, and B. Fox-Kemper, 2007: Mixed layer instabilities and restratification. J. Phys. Oceanogr., 37, 22282250, https://doi.org/10.1175/JPO3101.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bol, R., S. A. Henson, A. Rumyantseva, and N. Briggs, 2018: High-frequency variability of small-particle carbon export flux in the Northeast Atlantic. Global Biogeochem. Cycles, 32, 18031814, https://doi.org/10.1029/2018GB005963.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Buckingham, C. E., and Coauthors, 2016: Seasonality of submesoscale flows in the ocean surface boundary layer. Geophys. Res. Lett., 43, 21182126, https://doi.org/10.1002/2016GL068009.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Burd, A. B., and G. A. Jackson, 2009: Particle aggregation. Annu. Rev. Mar. Sci., 1, 6590, https://doi.org/10.1146/annurev.marine.010908.163904.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Callies, J., and R. Ferrari, 2018: Baroclinic instability in the presence of convection. J. Phys. Oceanogr., 48, 4560, https://doi.org/10.1175/JPO-D-17-0028.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capet, X., J. C. McWilliams, M. J. Molemaker, and A. Shchepetkin, 2008: Mesoscale to submesoscale transition in the California Current System. Part I: Flow structure, eddy flux, and observational tests. J. Phys. Oceanogr., 38, 2943, https://doi.org/10.1175/2007JPO3671.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chisholm, S. W., 2000: Oceanography: Stirring times in the Southern Ocean. Nature, 407, 685686, https://doi.org/10.1038/35037696.

  • Dall’Olmo, G., J. Dingle, L. Polimene, R. J. Brewin, and H. Claustre, 2016: Substantial energy input to the mesopelagic ecosystem from the seasonal mixed-layer pump. Nat. Geosci., 9, 820823, https://doi.org/10.1038/ngeo2818.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., 2008: Convection and the seeding of the North Atlantic bloom. J. Mar. Syst., 69, 233237, https://doi.org/10.1016/j.jmarsys.2005.08.005.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Eppley, R. W., and B. J. Peterson, 1979: Particulate organic matter flux and planktonic new production in the deep ocean. Nature, 282, 677680, https://doi.org/10.1038/282677a0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Erickson, Z. K., and A. F. Thompson, 2018: The seasonality of physically driven export at submesoscales in the northeast Atlantic Ocean. Global Biogeochem. Cycles, 32, 11441162, https://doi.org/10.1029/2018GB005927.

    • Search Google Scholar
    • Export Citation
  • Fennel, K., I. Cetinić, E. D’Asaro, C. Lee, and M. Perry, 2011: Autonomous data describe North Atlantic spring bloom. Eos, Trans. Amer. Geophys. Union, 92, 465466, https://doi.org/10.1029/2011EO500002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fox-Kemper, B., R. Ferrari, and R. Hallberg, 2008: Parameterization of mixed layer eddies. Part I: Theory and diagnosis. J. Phys. Oceanogr., 38, 11451165, https://doi.org/10.1175/2007JPO3792.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gardner, W. D., S. P. Chung, M. J. Richardson, and I. D. Walsh, 1995: The oceanic mixed-layer pump. Deep-Sea Res. II, 42, 757775, https://doi.org/10.1016/0967-0645(95)00037-Q.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hamlington, P. E., L. P. Van Roekel, B. Fox-Kemper, K. Julien, and G. P. Chini, 2014: Langmuir–submesoscale interactions: Descriptive analysis of multiscale frontal spindown simulations. J. Phys. Oceanogr., 44, 22492272, https://doi.org/10.1175/JPO-D-13-0139.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Henson, S. A., R. Sanders, E. Madsen, P. J. Morris, F. Le Moigne, and G. D. Quartly, 2011: A reduced estimate of the strength of the ocean’s biological carbon pump. Geophys. Res. Lett., 38, L04606, https://doi.org/10.1029/2011GL046735.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klein, P., and G. Lapeyre, 2009: The oceanic vertical pump induced by mesoscale and submesoscale turbulence. Annu. Rev. Mar. Sci., 1, 351375, https://doi.org/10.1146/annurev.marine.010908.163704.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Large, W. G., J. C. McWilliams, and S. C. Doney, 1994: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. Geophys., 32, 363403, https://doi.org/10.1029/94RG01872.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Laws, E. A., P. G. Falkowski, W. O. Smith Jr., H. Ducklow, and J. J. McCarthy, 2000: Temperature effects on export production in the open ocean. Global Biogeochem. Cycles, 14, 12311246, https://doi.org/10.1029/1999GB001229.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lévy, M., R. Ferrari, P. J. Franks, A. P. Martin, and P. Rivière, 2012: Bringing physics to life at the submesoscale. Geophys. Res. Lett., 39, L14602, https://doi.org/10.1029/2012GL052756.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, G., A. Bracco, and U. Passow, 2018: The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico. Elem. Sci. Anth., 6, 36, https://doi.org/10.1525/ELEMENTA.292.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mahadevan, A., 2016: The impact of submesoscale physics on primary productivity of plankton. Annu. Rev. Mar. Sci., 8, 161184, https://doi.org/10.1146/annurev-marine-010814-015912.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mahadevan, A., and A. Tandon, 2006: An analysis of mechanisms for submesoscale vertical motion at ocean fronts. Ocean Modell., 14, 241256, https://doi.org/10.1016/j.ocemod.2006.05.006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mahadevan, A., A. Tandon, and R. Ferrari, 2010: Rapid changes in mixed layer stratification driven by submesoscale instabilities and winds. J. Geophys. Res., 115, C03017, https://doi.org/10.1029/2008JC005203.

    • Search Google Scholar
    • Export Citation
  • Mahadevan, A., E. D’Asaro, C. Lee, and M. J. Perry, 2012: Eddy-driven stratification initiates North Atlantic spring phytoplankton blooms. Science, 337, 5458, https://doi.org/10.1126/science.1218740.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., 2016: Submesoscale currents in the ocean. Proc. Roy. Soc., A472, 20160117, https://doi.org/10.1098/RSPA.2016.0117.

  • Noh, Y., and S. Nakada, 2010: Estimation of the particle flux from the convective mixed layer by large eddy simulation. J. Geophys. Res., 115, C05007, https://doi.org/10.1029/2009JC005669.

    • Search Google Scholar
    • Export Citation
  • Noh, Y., I. Kang, M. Herold, and S. Raasch, 2006: Large eddy simulation of particle settling in the ocean mixed layer. Phys. Fluids, 18, 085109, https://doi.org/10.1063/1.2337098.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Omand, M. M., E. A. D’Asaro, C. M. Lee, M. J. Perry, N. Briggs, I. Cetinić, and A. Mahadevan, 2015: Eddy-driven subduction exports particulate organic carbon from the spring bloom. Science, 348, 222225, https://doi.org/10.1126/science.1260062.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Resplandy, L., M. Lévy, and D. J. McGillicuddy Jr., 2019: Effects of eddy-driven subduction on ocean biological carbon pump. Global Biogeochem. Cycles, 33, 10711084, https://doi.org/10.1029/2018GB006125.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rozema, W., H. J. Bae, P. Moin, and R. Verstappen, 2015: Minimum-dissipation models for large-eddy simulation. Phys. Fluids, 27, 085107, https://doi.org/10.1063/1.4928700.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smith, K. M., P. E. Hamlington, and B. Fox-Kemper, 2016: Effects of submesoscale turbulence on ocean tracers. J. Geophys. Res. Oceans, 121, 908933, https://doi.org/10.1002/2015JC011089.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, J. R., 2016: Turbulent mixing, restratification, and phytoplankton growth at a submesoscale eddy. Geophys. Res. Lett., 43, 57845792, https://doi.org/10.1002/2016GL069106.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, J. R., 2018: Accumulation and subduction of buoyant material at submesoscale fronts. J. Phys. Oceanogr., 48, 12331241, https://doi.org/10.1175/JPO-D-17-0269.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, J. R., and R. Ferrari, 2009: On the equilibration of a symmetrically unstable front via a secondary shear instability. J. Fluid Mech., 622, 103113, https://doi.org/10.1017/S0022112008005272.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, J. R., and R. Ferrari, 2010: Buoyancy and wind-driven convection at mixed layer density fronts. J. Phys. Oceanogr., 40, 12221242, https://doi.org/10.1175/2010JPO4365.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, J. R., and R. Ferrari, 2011: Ocean fronts trigger high latitude phytoplankton blooms. Geophys. Res. Lett., 38, L23601, https://doi.org/10.1029/2011GL049312.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thomas, L. N., 2005: Destruction of potential vorticity by winds. J. Phys. Oceanogr., 35, 24572466, https://doi.org/10.1175/JPO2830.1.

  • Thomas, L. N., A. Tandon, and A. Mahadevan, 2008: Submesoscale processes and dynamics. Ocean Modeling in an Eddying Regime, Geophys. Monogr., Vol. 177, Amer. Geophys. Union, 17–38.

    • Crossref
    • Export Citation
  • Thomas, L. N., J. R. Taylor, E. A. D’Asaro, C. M. Lee, J. M. Klymak, and A. Shcherbina, 2016: Symmetric instability, inertial oscillations, and turbulence at the Gulf Stream front. J. Phys. Oceanogr., 46, 197217, https://doi.org/10.1175/JPO-D-15-0008.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thompson, A. F., A. Lazar, C. Buckingham, A. C. Naveira Garabato, G. M. Damerell, and K. J. Heywood, 2016: Open-ocean submesoscale motions: A full seasonal cycle of mixed layer instabilities from gliders. J. Phys. Oceanogr., 46, 12851307, https://doi.org/10.1175/JPO-D-15-0170.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thorpe, S. A., 2005: The Turbulent Ocean. Cambridge University Press, 458 pp.

    • Crossref
    • Export Citation
  • Verstappen, R., 2018: How much eddy dissipation is needed to counterbalance the nonlinear production of small, unresolved scales in a large-eddy simulation of turbulence? Comput. Fluids, 176, 276284, https://doi.org/10.1016/J.COMPFLUID.2016.12.016.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vreugdenhil, C. A., and J. R. Taylor, 2018: Large-eddy simulations of stratified plane Couette flow using the anisotropic minimum-dissipation model. Phys. Fluids, 30, 085104, https://doi.org/10.1063/1.5037039.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Waite, A. M., and Coauthors, 2016: The wineglass effect shapes particle export to the deep ocean in mesoscale eddies. Geophys. Res. Lett., 43, 97919800, https://doi.org/10.1002/2015GL066463.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Whitt, D. B., and J. R. Taylor, 2017: Energetic submesoscales maintain strong mixed layer stratification during an autumn storm. J. Phys. Oceanogr., 47, 24192427, https://doi.org/10.1175/JPO-D-17-0130.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, X., A. C. Naveira Garabato, A. P. Martin, C. E. Buckingham, L. Brannigan, and Z. Su, 2019: An annual cycle of submesoscale vertical flow and restratification in the upper ocean. J. Phys. Oceanogr., 49, 14391461, https://doi.org/10.1175/JPO-D-18-0253.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 129 129 11
Full Text Views 32 32 3
PDF Downloads 41 41 4

The Influence of Submesoscales and Vertical Mixing on the Export of Sinking Tracers in Large-Eddy Simulations

View More View Less
  • 1 Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
© Get Permissions
Restricted access

Abstract

We use idealized large-eddy simulations (LES) and a simple analytical theory to study the influence of submesoscales on the concentration and export of sinking particles from the mixed layer. We find that restratification of the mixed layer following the development of submesoscales reduces the rate of vertical mixing which, in turn, enhances the export rate associated with gravitational settling. For a neutral tracer initially confined to the mixed layer, subinertial (submesoscale) motions enhance the downward tracer flux, consistent with previous studies. However, the sign of the advective flux associated with the concentration of sinking particles reverses, indicating reentrainment into the mixed layer. A new theory is developed to model the gravitational settling flux when the particle concentration is nonuniform. The theory broadly agrees with the LES results and allows us to extend the analysis to a wider range of parameters.

© 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: John R. Taylor, j.r.taylor@damtp.cam.ac.uk

Abstract

We use idealized large-eddy simulations (LES) and a simple analytical theory to study the influence of submesoscales on the concentration and export of sinking particles from the mixed layer. We find that restratification of the mixed layer following the development of submesoscales reduces the rate of vertical mixing which, in turn, enhances the export rate associated with gravitational settling. For a neutral tracer initially confined to the mixed layer, subinertial (submesoscale) motions enhance the downward tracer flux, consistent with previous studies. However, the sign of the advective flux associated with the concentration of sinking particles reverses, indicating reentrainment into the mixed layer. A new theory is developed to model the gravitational settling flux when the particle concentration is nonuniform. The theory broadly agrees with the LES results and allows us to extend the analysis to a wider range of parameters.

© 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: John R. Taylor, j.r.taylor@damtp.cam.ac.uk
Save