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Oceanography

Submesoscale Processes in the Upper Red Sea

Profile image of George KrokosGeorge Krokos

2022, Journal of Geophysical Research: Oceans

https://doi.org/10.1029/2021JC018015
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52 pages

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Abstract

Spatial-temporal submesoscale variabilities in the upper Red Sea and their 3 generation mechanisms, including frontogenesis, mixed-layer instability (MLI), 4 and symmetric instability (SI) are qualitatively investigated using high-resolution 5 simulations. The results suggest that submesoscales are critical hydrodynamic 6 components and stirring at submesoscale has a clear signal in the Red Sea,

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References (81)

  1. Abraham, E. R., and M. M. Bowen (2002), Chaotic stirring by a mesoscale surface-ocean flow, Chaos, doi:10.1063/1.1481615.
  2. Bachman, S. D., B. Fox-Kemper, J. R. Taylor, and L. N. Thomas (2017), Parameterization of frontal symmetric instabilities. i: Theory for resolved fronts, Ocean Modelling, doi: 10.1016/j.ocemod.2016.12.003.
  3. Beron-Vera, F. J., and J. H. LaCasce (2016), Statistics of simulated and observed pair separations in the gulf of mexico, Journal of Physical Oceanography, doi:10.1175/JPO- D-15-0127.1.
  4. Beron-Vera, F. J., and M. J. Olascoaga (2009), An assessment of the importance of chaotic stirring and turbulent mixing on the west florida shelf, Journal of Physical Oceanography, doi:10.1175/2009JPO4046.1.
  5. Beron-Vera, F. J., A. Hadjighasem, Q. Xia, M. J. Olascoaga, and G. Haller (2019), Coher- ent lagrangian swirls among submesoscale motions, Proceedings of the National Academy of Sciences of the United States of America, doi:10.1073/pnas.1701392115.
  6. Boccaletti, G., R. Ferrari, and B. Fox-Kemper (2007), Mixed layer instabilities and re- stratification, Journal of Physical Oceanography, doi:10.1175/JPO3101.1.
  7. Boffetta, G., G. Lacorata, G. Redaelli, and A. Vulpiani (2001), Detecting barriers to transport: A review of different techniques, Physica D: Nonlinear Phenomena, doi: 10.1016/S0167-2789(01)00330-X.
  8. Callies, J., G. Flierl, R. Ferrari, and B. Fox-Kemper (2015), The role of mixed- layer instabilities in submesoscale turbulence, Journal of Fluid Mechanics, doi: 10.1017/jfm.2015.700.
  9. R A F T February 25, 2022, 8:36am D R A F T Physical Oceanography, doi:10.1175/jpo-d-20-0267.1.
  10. Capet, X., J. C. McWilliams, M. J. Molemaker, and A. F. Shchepetkin (2008a), Mesoscale to submesoscale transition in the california current system. part i: Flow structure, eddy flux, and observational tests, Journal of Physical Oceanography, doi: 10.1175/2007JPO3671.1.
  11. Capet, X., J. C. McWilliams, M. J. Molemaker, and A. F. Shchepetkin (2008b), Mesoscale to submesoscale transition in the california current system. part iii: Energy balance and flux, Journal of Physical Oceanography, doi:10.1175/2008JPO3810.1.
  12. Capet, X., E. J. Campos, and A. M. Paiva (2008c), Submesoscale activity over the argen- tinian shelf, Geophysical Research Letters, doi:10.1029/2008GL034736.
  13. Chrysagi, E., L. Umlauf, P. Holtermann, K. Klingbeil, and H. Burchard (2021), High- resolution simulations of submesoscale processes in the baltic sea: The role of storm events, Journal of Geophysical Research: Oceans, 126, doi:10.1029/2020JC016411.
  14. Couvelard, X., F. Dumas, V. Garnier, A. L. Ponte, C. Talandier, and A. M. Treguier (2015), Mixed layer formation and restratification in presence of mesoscale and subme- soscale turbulence, Ocean Modelling, 96, doi:10.1016/j.ocemod.2015.10.004.
  15. Damien, P., A. Bosse, P. Testor, P. Marsaleix, and C. Estournel (2017), Modeling postcon- vective submesoscale coherent vortices in the northwestern mediterranean sea, Journal of Geophysical Research: Oceans, doi:10.1002/2016JC012114.
  16. Dee, D. P., S. M. Uppala, A. J. Simmons, P. Berrisford, P. Poli, S. Kobayashi, U. Andrae, M. A. Balmaseda, G. Balsamo, P. Bauer, P. Bechtold, A. C. Beljaars, L. van de Berg, D R A F T February 25, 2022, 8:36am D R A F T Prognosis and impact, Journal of Physical Oceanography, doi:10.1175/2007JPO3788.1. Fox-Kemper, B., R. Ferrari, and R. Hallberg (2008), Parameterization of mixed layer eddies. part i: Theory and diagnosis, Journal of Physical Oceanography, doi: 10.1175/2007JPO3792.1.
  17. Gittings, J. A., D. E. Raitsos, G. Krokos, and I. Hoteit (2018), Impacts of warming on phytoplankton abundance and phenology in a typical tropical marine ecosystem, Scientific Reports, doi:10.1038/s41598-018-20560-5.
  18. Gittings, J. A., D. E. Raitsos, M. Kheireddine, M. F. Racault, H. Claustre, and I. Hoteit (2019a), Evaluating tropical phytoplankton phenology metrics using contemporary tools, Scientific Reports, doi:10.1038/s41598-018-37370-4.
  19. Gittings, J. A., R. J. Brewin, D. E. Raitsos, M. Kheireddine, M. Ouhssain, B. H. Jones, and I. Hoteit (2019b), Remotely sensing phytoplankton size structure in the red sea, Remote Sensing of Environment, doi:10.1016/j.rse.2019.111387.
  20. Gittings, J. A., D. E. Raitsos, R. J. Brewin, and I. Hoteit (2021), Links between phenology of large phytoplankton and fisheries in the northern and central red sea, Remote Sensing, doi:10.3390/rs13020231.
  21. Gough, M. K., F. J. Beron-Vera, M. J. Olascoaga, J. Sheinbaum, J. Jouanno, and R. Duran (2019), Persistent lagrangian transport patterns in the northwestern gulf of mexico, Journal of Physical Oceanography, doi:10.1175/JPO-D-17-0207.
  22. Gouveia, M. B., R. Duran, J. A. Lorenzzetti, A. T. Assireu, R. Toste, L. P. de, and D. F. Gherardi (2021), Persistent meanders and eddies lead to quasi-steady la- D R A F T February 25, 2022, 8:36am D R A F T
  23. Gula, J., J. J. Molemaker, and J. C. Mcwilliams (2014), Submesoscale cold filaments in the gulf stream, Journal of Physical Oceanography, doi:10.1175/JPO-D-14-0029.1.
  24. Guo, D., T. R. Akylas, P. Zhan, A. Kartadikaria, and I. Hoteit (2016), On the generation and evolution of internal solitary waves in the southern red sea, Journal of Geophysical Research: Oceans, doi:10.1002/2016JC012221.
  25. Guo, D., A. Kartadikaria, P. Zhan, J. Xie, M. Li, and I. Hoteit (2018), Baroclinic tides simulation in the red sea: Comparison to observations and basic characteristics, Journal of Geophysical Research: Oceans, doi:10.1029/2018JC013970.
  26. Haine, T. W., and J. Marshall (1998), Gravitational, symmetric, and baroclinic insta- bility of the ocean mixed layer, Journal of Physical Oceanography, doi:10.1175/1520- 0485(1998)028¡0634:GSABIO¿2.0.CO;2.
  27. Hakim, G. J., C. Snyder, and D. J. Muraki (2002), A new surface model for cyclone-anticyclone asymmetry, Journal of the Atmospheric Sciences, doi:10.1175/1520- 0469(2002)059¡2405:ANSMFC¿2.0.CO;2.
  28. Haller, G. (2015), Lagrangian coherent structures, Annual Review of Fluid Mechanics, 47, 137-162, doi:10.1146/annurev-fluid-010313-141322, doi: 10.1146/annurev-fluid-010313- 141322.
  29. Haney, S., B. Fox-Kemper, K. Julien, and A. Webb (2015), Symmetric and geostrophic instabilities in the wave-forced ocean mixed layer, Journal of Physical Oceanography, doi:10.1175/JPO-D-15-0044.
  30. R A F T February 25, 2022, 8:36am D R A F T
  31. Hoskins, B. J. (1974), The role of potential vorticity in symmetric stability and instability, doi:10.1002/qj.49710042520.
  32. Hoskins, J. B. (1982), The mathematical theory of frontogenesis., IN: ANNUAL REVIEW OF FLUID MECHANICS, doi:10.1146/annurev.fl.14.010182.001023.
  33. Hoteit, I., Y. Abualnaja, S. Afzal, B. Ait-El-Fquih, T. Akylas, C. Antony, C. Daw- son, K. Asfahani, R. J. Brewin, L. Cavaleri, I. Cerovecki, B. Cornuelle, S. Desamsetti, R. Attada, H. Dasari, J. Sanchez-Garrido, L. Genevier, M. E. Gharamti, J. A. Git- tings, E. Gokul, G. Gopalakrishnan, D. Guo, B. Hadri, M. Hadwiger, M. A. Hammoud, M. Hendershott, M. Hittawe, A. Karumuri, O. Knio, A. Khl, S. Kortas, G. Krokos, R. Kunchala, L. Issa, I. Lakkis, S. Langodan, P. Lermusiaux, T. Luong, J. Ma, O. L. Maitre, M. Mazloff, S. E. Mohtar, V. P. Papadopoulos, T. Platt, L. Pratt, N. Raboudi, M.-F. Racault, D. E. Raitsos, S. Razak, S. Sanikommu, S. Sathyendranath, S. Sofianos, A. Subramanian, R. Sun, E. Titi, H. Toye, G. Triantafyllou, K. Tsiaras, P. Vasou, Y. Viswanadhapalli, Y. Wang, F. Yao, P. Zhan, and G. Zodiatis (2020), Towards an end-to-end analysis and prediction system for weather, climate, and marine applications in the red sea, Bulletin of the American Meteorological Society, doi:10.1175/bams-d-19- 0005.
  34. Huhn, F., A. V. Kameke, V. Prez-Muuzuri, M. J. Olascoaga, and F. J. Beron-Vera (2012), The impact of advective transport by the south indian ocean countercurrent on the madagascar plankton bloom, Geophysical Research Letters, doi:10.1029/2012GL051246.
  35. Jing, Z., S. Wang, L. Wu, P. Chang, Q. Zhang, B. Sun, X. Ma, B. Qiu, J. Small, F. F. Jin, Z. Chen, B. Gan, Y. Yang, H. Yang, and X. Wan (2020), Maintenance of mid-latitude oceanic fronts by mesoscale eddies, Science Advances, doi:10.1126/sciadv.aba7880.
  36. R A F T February 25, 2022, 8:36am D R A F T subtropical ocean, Journal of Physical Oceanography, doi:10.1175/JPO-D-20-0076.1. Kheireddine, M., G. Dall'Olmo, M. Ouhssain, G. Krokos, H. Claustre, C. Schmechtig, A. Poteau, P. Zhan, I. Hoteit, and B. Jones (2020), Organic carbon export and loss rates in the red sea, Global Biogeochemical Cycles, 34, doi:10.1029/2020GB006650.
  37. Klein, P., B. L. Hua, G. Lapeyre, X. Capet, S. L. Gentil, and H. Sasaki (2008), Upper ocean turbulence from high-resolution 3d simulations, Journal of Physical Oceanogra- phy, doi:10.1175/2007JPO3773.1.
  38. Kraichnan, R. H. (1971), Inertial-range transfer in two-and three-dimensional turbulence, Journal of Fluid Mechanics, 47 (3), 525-535.
  39. Krokos, G., I. Ceroveki, P. Zhan, M. Hendershott, and I. Hoteit (2019), Seasonal evolution of the mixed layers in the red sea, Journal of Geophysical Research: Oceans, Under revi.
  40. Langodan, S., L. Cavaleri, Y. Vishwanadhapalli, A. Pomaro, L. Bertotti, and I. Hoteit (2017), The climatology of the red seapart 1: the wind, International Journal of Cli- matology, doi:10.1002/joc.5103.
  41. Large, W. G., J. C. McWilliams, and S. C. Doney (1994), Oceanic vertical mix- ing: A review and a model with a nonlocal boundary layer parameterization, doi: 10.1029/94RG01872.
  42. Lvy, M., P. Klein, and A. M. Treguier (2001), Impact of sub-mesoscale physics on pro- duction and subduction of phytoplankton in an oligotrophic regime, Journal of Marine Research, doi:10.1357/002224001762842181.
  43. D R A F T February 25, 2022, 8:36am D R A F T Local and remote effects, Ocean Modelling, doi:10.1016/j.ocemod.2011.12.003.
  44. Mahadevan, A., E. D'Asaro, C. Lee, and M. J. Perry (2012), Eddy-driven stratification initiates north atlantic spring phytoplankton blooms, Science, doi: 10.1126/science.1218740.
  45. Marshall, J., C. Hill, L. Perelman, and A. Adcroft (1997), Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling, Journal of Geophysical Research, 102, 5733, doi: 10.1029/96JC02776.
  46. Martin, A. (2003), Phytoplankton patchiness: the role of lateral stirring and mixing, Progress in Oceanography, doi:10.1016/s0079-6611(03)00085-5.
  47. McWilliams, J. C. (2016), Submesoscale currents in the ocean, doi: 10.1098/rspa.2016.0117.
  48. McWilliams, J. C. (2017), Submesoscale surface fronts and filaments: Secondary circulation, buoyancy flux, and frontogenesis, Journal of Fluid Mechanics, doi: 10.1017/jfm.2017.294.
  49. McWilliams, J. C. (2019), A survey of submesoscale currents, Geoscience Letters, doi: 10.1186/s40562-019-0133-3.
  50. McWilliams, J. C., F. Colas, and M. J. Molemaker (2009), Cold filamentary inten- sification and oceanic surface convergence lines, Geophysical Research Letters, doi: 10.1029/2009GL039402.
  51. Mensa, J. A., Z. Garraffo, A. Griffa, T. M. zgkmen, A. Haza, and M. Veneziani (2013), Seasonality of the submesoscale dynamics in the gulf stream region, Ocean Dynamics, simulations, Journal of Physical Oceanography, doi:10.1175/JPO-D-16-0168.1.
  52. Rocha, C. B., T. K. Chereskin, S. T. Gille, and D. Menemenlis (2016), Mesoscale to submesoscale wavenumber spectra in drake passage, Journal of Physical Oceanography, doi:10.1175/JPO-D-15-0087.1.
  53. Sanikommu, S., H. Toye, P. Zhan, S. Langodan, G. Krokos, O. Knio, and I. Hoteit (2020), Impact of atmospheric and model physics perturbations on a high-resolution ensemble data assimilation system of the red sea.
  54. Sasaki, H., P. Klein, B. Qiu, and Y. Sasai (2014), Impact of oceanic-scale interactions on the seasonal modulation of ocean dynamics by the atmosphere, Nature Communications, doi:10.1038/ncomms6636.
  55. Sasaki, H., P. Klein, Y. Sasai, and B. Qiu (2017), Regionality and seasonality of sub- mesoscale and mesoscale turbulence in the north pacific ocean, Ocean Dynamics, doi: 10.1007/s10236-017-1083-y.
  56. Schubert, R., J. Gula, R. J. Greatbatch, B. Baschek, and A. Biastoch (2020), The subme- soscale kinetic energy cascade: Mesoscale absorption of submesoscale mixed layer eddies and frontal downscale fluxes, Journal of Physical Oceanography, doi:10.1175/JPO-D-19- 0311.
  57. Scott, R. B., and B. K. Arbic (2007), Spectral energy fluxes in geostrophic tur- bulence: Implications for ocean energetics, Journal of Physical Oceanography, doi: 10.1175/JPO3027.1.
  58. R A F T February 25, 2022, 8:36am D R A F T
  59. Serra, M., and G. Haller (2016), Objective eulerian coherent structures, Chaos, doi: 10.1063/1.4951720.
  60. Shcherbina, A. Y., E. A. D'Asaro, C. M. Lee, J. M. Klymak, M. J. Molemaker, and J. C. McWilliams (2013), Statistics of vertical vorticity, divergence, and strain in a developed submesoscale turbulence field, Geophysical Research Letters, doi:10.1002/grl.50919.
  61. Srinivasan, K., J. C. McWilliams, L. Renault, H. G. Hristova, J. Molemaker, and W. S. Kessler (2017), Topographic and mixed layer submesoscale currents in the near-surface southwestern tropical pacific, Journal of Physical Oceanography, doi:10.1175/JPO-D- 16-0216.1.
  62. Stamper, M. A., and J. R. Taylor (2017), The transition from symmetric to baroclinic instability in the eady model, Ocean Dynamics, doi:10.1007/s10236-016-1011-6.
  63. Stone, P. H. (1966), On non-geostrophic baroclinic stability, Journal of the Atmospheric Sciences, doi:10.1175/1520-0469(1966)023¡0390:ongbs¿2.0.co;2.
  64. Su, Z., J. Wang, P. Klein, A. F. Thompson, and D. Menemenlis (2018), Ocean sub- mesoscales as a key component of the global heat budget, Nature Communications, doi:10.1038/s41467-018-02983-w.
  65. Taylor, J. R., and R. Ferrari (2009), On the equilibration of a symmetrically un- stable front via a secondary shear instability, Journal of Fluid Mechanics, doi: 10.1017/S0022112008005272.
  66. Thomas, L. N. (2005), Destruction of potential vorticity by winds, Journal of Physical Oceanography, doi:10.1175/JPO2830.1.
  67. R A F T February 25, 2022, 8:36am D R A F T doi:10.1175/JPO-D-17-0070.1.
  68. Wang, Y., D. E. Raitsos, G. Krokos, J. A. Gittings, P. Zhan, and I. Hoteit (2019), Physical connectivity simulations reveal dynamic linkages between coral reefs in the southern red sea and the indian ocean, Scientific Reports, doi:10.1038/s41598-019-53126-0.
  69. Waugh, D. W., and E. R. Abraham (2008), Stirring in the global surface ocean, Geophys- ical Research Letters, doi:10.1029/2008GL035526.
  70. Waugh, D. W., E. R. Abraham, and M. M. Bowen (2006), Spatial variations of stirring in the surface ocean: A case study of the tasman sea, Journal of Physical Oceanography, doi:10.1175/JPO2865.1.
  71. Whitt, D. B., and J. R. Taylor (2017), Energetic submesoscales maintain strong mixed layer stratification during an autumn storm, Journal of Physical Oceanography, 47, doi:10.1175/JPO-D-17-0130.1.
  72. Yao, F., I. Hoteit, L. J. Pratt, A. S. Bower, P. Zhai, A. Khl, and G. Gopalakrish- nan (2014a), Seasonal overturning circulation in the red sea: 1. model validation and summer circulation, Journal of Geophysical Research: Oceans, p. 22382262, doi: 10.1002/2013JC009004.
  73. Yao, F., I. Hoteit, L. J. Pratt, A. S. Bower, A. Khl, G. Gopalakrishnan, and D. Rivas (2014b), Seasonal overturning circulation in the red sea. 2: Winter circulation, Journal of Geophysical Research: Oceans, p. 22632289, doi:10.1002/2013JC009331.
  74. Yu, X., A. C. N. 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, Journal of Physical Oceanography, doi:10.1175/JPO-D-18-0253.1. doi:10.1029/2020JC016714.
  75. Zhai, P., and A. Bower (2013), The response of the red sea to a strong wind jet near the tokar gap in summer, Journal of Geophysical Research: Oceans, 118 (1), 421-434.
  76. Zhan, P., A. C. Subramanian, F. Yao, and I. Hoteit (2014), Eddies in the red sea: A statistical and dynamical study, Journal of Geophysical Research: Oceans, 119, 3909- 3925, doi:10.1002/2013JC009563.
  77. Zhan, P., F. Yao, A. R. Kartadikaria, Y. Viswanadhapalli, G. Gopalakrishnan, and I. Hoteit (2015), Far-field ocean conditions and concentrate discharges modeling along the saudi coast of the red sea, doi:10.1007/978-3-319-13203-7{ }21.
  78. Zhan, P., A. C. Subramanian, F. Yao, A. R. Kartadikaria, D. Guo, and I. Hoteit (2016), The eddy kinetic energy budget in the red sea, Journal of Geophysical Research: Oceans, doi:10.1002/2015JC011589.
  79. Zhan, P., G. Gopalakrishnan, A. C. Subramanian, D. Guo, and I. Hoteit (2018), Sensitivity studies of the red sea eddies using adjoint method, Journal of Geophysical Research: Oceans, 0, doi:10.1029/2018JC014531.
  80. Zhan, P., G. Krokos, D. Guo, and I. Hoteit (2019), Three-dimensional signature of the red sea eddies and eddy-induced transport, Geophysical Research Letters, 46, 2167-2177, doi:10.1029/2018GL081387, doi: 10.1029/2018GL081387.
  81. Zhan, P., G. Krokos, S. Langodan, D. Guo, H. Dasari, V. P. Papadopoulos, P. F. Lermusi- aux, O. M. Knio, and I. Hoteit (2021), Coastal circulation and water transport proper- ties of the red sea project lagoon, Ocean Modelling, doi:10.1016/j.ocemod.2021.101791. D R A F T February 25, 2022, 8:36am D R A F T

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