• Allen, J. T., D. Smeed, J. Tintoré, and S. Ruiz, 2001: Mesoscale subduction at the Almeria–Oran front: Part I: Ageostrophic flow. J. Mar. Syst., 30, 263285, https://doi.org/10.1016/S0924-7963(01)00062-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Arnone, R. A., 1987: Satellite-derived color-temperature relationship in the Alboran Sea. Remote Sens. Environ., 23, 417437, https://doi.org/10.1016/0034-4257(87)90099-X.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barkan, R., K. B. Winters, and S. G. Llewellyn Smith, 2015: Energy cascades and loss of balance in a reentrant channel forced by wind stress and buoyancy fluxes. J. Phys. Oceanogr., 45, 272293, https://doi.org/10.1175/JPO-D-14-0068.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barkan, R., M. J. Molemaker, K. Srinivasan, J. C. McWilliams, and E. A. D’Asaro, 2019: The role of horizontal divergence in submesoscale frontogenesis. J. Phys. Oceanogr., 49, 15931618, https://doi.org/10.1175/JPO-D-18-0162.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Becker, J. J., and et al. , 2009: Global bathymetry and elevation data at 30 arc seconds resolution: SRTM30_PLUS. Mar. Geod., 32, 355371, https://doi.org/10.1080/01490410903297766.

    • 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
  • Bracco, A., G. Liu, and D. Sun, 2019: Mesoscale-submesoscale interactions in the Gulf of Mexico: From oil dispersion to climate. Chaos Solitons Fractals, 119, 6372, https://doi.org/10.1016/j.chaos.2018.12.012.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brett, G. J., L. J. Pratt, I. I. Rypina, and J. C. Sánchez-Garrido, 2020: The Western Alboran Gyre: An analysis of its properties and its exchange with surrounding water. J. Phys. Oceanogr., 50, 33793402, https://doi.org/10.1175/JPO-D-20-0028.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bryden, H. L., and T. H. Kinder, 1991: Steady two-layer exchange through the Strait of Gibraltar. Deep-Sea Res. I, 38, S445S463, https://doi.org/10.1016/S0198-0149(12)80020-3.

    • 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 II: Frontal processes. J. Phys. Oceanogr., 38, 4464, https://doi.org/10.1175/2007JPO3672.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Capó, E., 2019: Submesoscale dynamics in the western Mediterranean Sea. Ph.D. thesis, University of the Balearic Islands, 136 pp., http://hdl.handle.net/10261/226748.

  • Cheney, R. E., and R. A. Doblar, 1982: Structure and variability of the Alboran Sea frontal system. J. Geophys. Res., 87, 585594, https://doi.org/10.1029/JC087iC01p00585.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., C. Lee, L. Rainville, R. Harcourt, and L. Thomas, 2011: Enhanced turbulence and energy dissipation at ocean fronts. Science, 332, 318322, https://doi.org/10.1126/science.1201515.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., and et al. , 2018: Ocean convergence and the dispersion of flotsam. Proc. Natl. Acad. Sci. USA, 115, 11621167, https://doi.org/10.1073/pnas.1718453115.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • D’Ortenzio, F., D. Iudicone, C. de Boyer Montegut, P. Testor, D. Antoine, S. Marullo, R. Santoleri, and G. Madec, 2005: Seasonal variability of the mixed layer depth in the Mediterranean Sea as derived from in situ profiles. Geophys. Res. Lett., 32, L12605, https://doi.org/10.1029/2005GL022463.

    • Search Google Scholar
    • Export Citation
  • Flexas, M., D. Gomis, S. Ruiz, A. Pascual, and P. León, 2006: In situ and satellite observations of the eastward migration of the Western Alboran Sea Gyre. Prog. Oceanogr., 70, 486509, https://doi.org/10.1016/j.pocean.2006.03.017.

    • 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
  • García Lafuente, J., J. Delgado, A. Sánchez Román, J. Soto, L. Carracedo, and G. Díaz del Río, 2009: Interannual variability of the Mediterranean outflow observed in Espartel sill, Western Strait of Gibraltar. J. Geophys. Res., 114, C10018, https://doi.org/10.1029/2009JC005496.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Geyer, W., and D. Ralston, 2015: Estuarine frontogenesis. J. Phys. Oceanogr., 45, 546561, https://doi.org/10.1175/JPO-D-14-0082.1.

  • Gula, J., M. J. Molemaker, and J. C. McWilliams, 2014: Submesoscale cold filaments in the Gulf Stream. J. Phys. Oceanogr., 44, 26172643, https://doi.org/10.1175/JPO-D-14-0029.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gula, J., M. J. Molemaker, and J. C. McWilliams, 2016: Submesoscale dynamics of a Gulf Stream frontal eddy in the South Atlantic Bight. J. Phys. Oceanogr., 46, 305325, https://doi.org/10.1175/JPO-D-14-0258.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heburn, G. W., and P. E. La Violette, 1990: Variations in the structure of the anticyclonic gyres found in the Alboran Sea. J. Geophys. Res., 95, 15991613, https://doi.org/10.1029/JC095iC02p01599.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., 1982: The mathematical theory of frontogenesis. Annu. Rev. Fluid Mech., 14, 131151, https://doi.org/10.1146/annurev.fl.14.010182.001023.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., and F. P. Bretherton, 1972: Atmospheric frontogenesis models: Mathematical formulation and solution. J. Atmos. Sci., 29, 1137, https://doi.org/10.1175/1520-0469(1972)029<0011:AFMMFA>2.0.CO;2.

    • 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
  • Larnicol, G., N. Ayoub, and P. Le Traon, 2002: Major changes in Mediterranean Sea level variability from 7 years of TOPEX/Poseidon and ERS-1/2 data. J. Mar. Syst., 33-34, 6389, https://doi.org/10.1016/S0924-7963(02)00053-2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lellouche, J.-M., and et al. , 2018: Recent updates to the Copernicus Marine Service global ocean monitoring and forecasting real-time 1/12°. Ocean Sci., 14, 10931126, https://doi.org/10.5194/os-14-1093-2018.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lemarié, F., J. Kurian, A. F. Shchepetkin, M. J. Molemaker, F. Colas, and J. C. McWilliams, 2012: Are there inescapable issues prohibiting the use of terrain-following coordinates in climate models? Ocean Modell., 42, 5779, https://doi.org/10.1016/j.ocemod.2011.11.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lévy, M., P. J. Franks, and K. S. Smith, 2018: The role of submesoscale currents in structuring marine ecosystems. Nat. Commun., 9, 4758, https://doi.org/10.1038/s41467-018-07059-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lodise, J., and et al. , 2020: Investigating the formation of submesoscale structures along mesoscale fronts and estimating kinematic quantities using Lagrangian drifters. Fluids, 5, 159, https://doi.org/10.3390/fluids5030159.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Macias, D., E. Garcia-Gorriz, and A. Stips, 2016: The seasonal cycle of the Atlantic Jet dynamics in the Alboran Sea: Direct atmospheric forcing versus Mediterranean thermohaline circulation. Ocean Dyn., 66, 137151, https://doi.org/10.1007/s10236-015-0914-y.

    • 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., A. Pascual, D. L. Rudnick, S. Ruiz, J. Tintoré, and E. D’Asaro, 2020: Coherent pathways for vertical transport from the surface ocean to interior. Bull. Amer. Meteor. Soc., 101, E1996E2004, https://doi.org/10.1175/BAMS-D-19-0305.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., J. C. McWilliams, and A. Shchepetkin, 2001: Open boundary conditions for long-term integration of regional oceanic models. Ocean Modell., 3, 120, https://doi.org/10.1016/S1463-5003(00)00013-5.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marchesiello, P., L. Debreu, and X. Couvelard, 2009: Spurious diapycnal mixing in terrain-following coordinate models: The problem and a solution. Ocean Modell., 26, 156169, https://doi.org/10.1016/j.ocemod.2008.09.004.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mason, E., J. Molemaker, A. F. Shchepetkin, F. Colas, J. C. McWilliams, and P. Sangrà, 2010: Procedures for offline grid nesting in regional ocean models. Ocean Modell., 35, 115, https://doi.org/10.1016/j.ocemod.2010.05.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mason, E., S. Ruiz, R. Bourdalle-Badie, G. Reffray, M. García-Sotillo, and A. Pascual, 2019: New insight into 3-D mesoscale eddy properties from CMEMS operational models in the western Mediterranean. Ocean Sci., 15, 11111131, https://doi.org/10.5194/os-15-1111-2019.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., 2016: Submesoscale currents in the ocean. Proc. Roy. Soc. London, 472, 20160117, https://doi.org/10.1098/RSPA.2016.0117.

    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., 2017: Submesoscale surface fronts and filaments: Secondary circulation, buoyancy flux, and frontogenesis. J. Fluid Mech., 823, 391432, https://doi.org/10.1017/jfm.2017.294.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., 2020: Oceanic frontogenesis. Annu. Rev. Mar. Sci., 13, 227253, https://doi.org/10.1146/ANNUREV-MARINE-032320-120725.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., J. Gula, M. J. Molemaker, L. Renault, and A. F. Shchepetkin, 2015: Filament frontogenesis by boundary layer turbulence. J. Phys. Oceanogr., 45, 19882005, https://doi.org/10.1175/JPO-D-14-0211.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McWilliams, J. C., J. Gula, and M. J. Molemaker, 2019: Frontogenesis and secondary circulation along the North Wall of the Gulf Stream. J. Phys. Oceanogr., 49, 893916, https://doi.org/10.1175/JPO-D-18-0203.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Menemenlis, D., I. Fukumori, and T. Lee, 2007: Atlantic to Mediterranean sea level difference driven by winds near Gibraltar Strait. J. Phys. Oceanogr., 37, 359376, https://doi.org/10.1175/JPO3015.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Millot, C., 1999: Circulation in the western Mediterranean Sea. J. Mar. Syst., 20, 423442, https://doi.org/10.1016/S0924-7963(98)00078-5.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nagai, T., A. Tandon, H. Yamazaki, and M. J. Doubell, 2009: Evidence of enhanced turbulent dissipation in the frontogenetic Kuroshio Front thermocline. Geophys. Res. Lett., 36, L12609, https://doi.org/10.1029/2009GL038832.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Naranjo, C., J. Garcia-Lafuente, G. Sannino, and J. Sanchez-Garrido, 2014: How much do tides affect the circulation of the Mediterranean Sea? From local processes in the Strait of Gibraltar to basin-scale effects. Prog. Oceanogr., 127, 108116, https://doi.org/10.1016/j.pocean.2014.06.005.

    • 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
  • Peliz, A., D. Boutov, R. M. Cardoso, J. Delgado, and P. M. Soares, 2013: The Gulf of Cadiz–Alboran Sea sub-basin: Model setup, exchange and seasonal variability. Ocean Modell., 61, 4967, https://doi.org/10.1016/j.ocemod.2012.10.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Penven, P., L. Debreu, P. Marchesiello, and J. C. McWilliams, 2006: Evaluation and application of the ROMS 1-way embedding procedure to the central California Upwelling System. Ocean Modell., 12, 157187, https://doi.org/10.1016/j.ocemod.2005.05.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Renault, L., T. Oguz, A. Pascual, G. Vizoso, and J. Tintoré, 2012: Surface circulation in the Alboran Sea (western Mediterranean) inferred from remotely sensed data. J. Geophys. Res., 117, C08009, https://doi.org/10.1029/2011JC007659.

    • Search Google Scholar
    • Export Citation
  • Roden, G. I., 1980: On the variability of surface temperature fronts in the western Pacific, as detected by satellite. J. Geophys. Res., 85, 27042710, https://doi.org/10.1029/JC085iC05p02704.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rudnick, D. L., and R. E. Davis, 1988: Frontogenesis in mixed layers. J. Phys. Oceanogr., 18, 434457, https://doi.org/10.1175/1520-0485(1988)018<0434:FIML>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rudnick, D. L., and J. Luyten, 1996: Intensive surveys of the Azores Front: 2. Inferring the geostrophic and vertical velocity fields. J. Geophys. Res., 101, 16 29116 303, https://doi.org/10.1029/96JC01144.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rudnick, D. L., N. Zarokanellos, J. Allen, S. Ruiz, A. Pascual, and J. Tintoré, 2020: Observations of the Almeria–Oran front by underwater gliders. Ocean Sciences Meeting 2020, San Diego, CA, Amer. Geophys. Union, Abstract PS21A-05.

  • Ruiz, J., and et al. , 2001: Surface distribution of chlorophyll, particles and gelbstoff in the Atlantic jet of the Alborán Sea: From submesoscale to subinertial scales of variability. J. Mar. Syst., 29, 277292, https://doi.org/10.1016/S0924-7963(01)00020-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sánchez Garrido, J. C., J. García Lafuente, F. Criado Aldeanueva, A. Baquerizo, and G. Sannino, 2008: Time-spatial variability observed in velocity of propagation of the internal bore in the Strait of Gibraltar. J. Geophys. Res. Oceans, 113, C07034, https://doi.org/10.1029/2007JC004624.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sánchez-Román, A., G. Jordà, G. Sannino, and D. Gomis, 2018: Modelling study of transformations of the exchange flows along the Strait of Gibraltar. Ocean Sci., 14, 15471566, https://doi.org/10.5194/os-14-1547-2018.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sannino, G., J. S. Garrido, L. Liberti, and L. Pratt, 2014: Exchange flow through the Strait of Gibraltar as simulated by a σ-coordinate hydrostatic model and a z-coordinate non-hydrostatic model. The Mediterranean Sea: Temporal Variability and Spatial Patterns, Geophys. Monogr. Ser., Vol. 202, Amer. Geophys. Union, 25–50, https://doi.org/10.1002/9781118847572.ch3.

    • Crossref
    • Export Citation
  • Sarhan, T., J. G. Lafuente, M. Vargas, J. M. Vargas, and F. Plaza, 2000: Upwelling mechanisms in the northwestern Alboran Sea. J. Mar. Syst., 23, 317331, https://doi.org/10.1016/S0924-7963(99)00068-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schubert, R., J. Gula, R. J. Greatbatch, B. Baschek, and A. Biastoch, 2020: The submesoscale kinetic energy cascade: Mesoscale absorption of submesoscale mixed layer eddies and frontal downscale fluxes. J. Phys. Oceanogr., 50, 25732589, https://doi.org/10.1175/JPO-D-19-0311.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A. F., 2015: An adaptive, Courant-number-dependent implicit scheme for vertical advection in oceanic modeling. Ocean Modell., 91, 3869, https://doi.org/10.1016/j.ocemod.2015.03.006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A. F., and J. C. McWilliams, 2005: The Regional Oceanic Modeling System (ROMS): A split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Modell., 9, 347404, https://doi.org/10.1016/j.ocemod.2004.08.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shchepetkin, A. F., and J. C. McWilliams, 2009: Computational kernel algorithms for fine-scale, multiprocess, longtime oceanic simulations. Computational Methods for the Atmosphere and the Oceans, R. M. Temam and J. J. Tribbia, Eds., Vol. 14, Handbook of Numerical Analysis, Elsevier, 121–183.

    • Crossref
    • Export Citation
  • Su, Z., J. Wang, P. Klein, A. F. Thompson, and D. Menemenlis, 2018: Ocean submesoscales as a key component of the global heat budget. Nat. Commun., 9, 775, https://doi.org/10.1038/s41467-018-02983-w.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sullivan, P. P., and J. C. McWilliams, 2018: Frontogenesis and frontal arrest of a dense filament in the oceanic surface boundary layer. J. Fluid Mech., 837, 341380, https://doi.org/10.1017/jfm.2017.833.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 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, https://doi.org/10.1029/177GM04.

    • Crossref
    • Export Citation
  • Tintoré, J., P. La Violette, I. Blade, and A. Cruzado, 1988: A study of an intense density front in the eastern Alboran Sea: The Almeria–Oran front. J. Phys. Oceanogr., 18, 13841397, https://doi.org/10.1175/1520-0485(1988)018<1384:ASOAID>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vargas-Yáñez, M., F. Plaza, J. Garcıa-Lafuente, T. Sarhan, J. Vargas, and P. Vélez-Belchí, 2002: About the seasonal variability of the Alboran Sea circulation. J. Mar. Syst., 35, 229248, https://doi.org/10.1016/S0924-7963(02)00128-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Viúdez, Á., and J. Tintoré, 1995: Time and space variability in the eastern Alboran Sea from March to May 1990. J. Geophys. Res., 100, 85718586, https://doi.org/10.1029/94JC03129.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Viúdez, Á., J. Tintoré, and R. L. Haney, 1996: Circulation in the Alboran Sea as determined by quasi-synoptic hydrographic observations. Part I: Three-dimensional structure of the two anticyclonic gyres. J. Phys. Oceanogr., 26, 684705, https://doi.org/10.1175/1520-0485(1996)026<0684:CITASA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Viúdez, Á., R. L. Haney, and J. Vázquez-Cuervo, 1998: The deflection and division of an oceanic baroclinic jet by a coastal boundary: A case study in the Alboran Sea. J. Phys. Oceanogr., 28, 289308, https://doi.org/10.1175/1520-0485(1998)028<0289:TDADOA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, T., R. Barkan, J. McWilliams, and M. Molemaker, 2021: Structure of submesoscale fronts of the Mississippi River plume. J. Phys. Oceanogr., 51, 11131131, https://doi.org/10.1175/JPO-D-20-0191.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ziegenbein, J., 1969: Short internal waves in the Strait of Gibraltar. Deep-Sea Res., 16, 479487, https://doi.org/10.1016/0011-7471(69)90036-9.

    • Search Google Scholar
    • Export Citation
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Intermittent Frontogenesis in the Alboran Sea

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  • 1 Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California
  • | 2 Instituto Mediterráneo de Estudios Avanzados, UIB-CSIC, Esporles, Balearic Islands, Spain
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Abstract

We present a phenomenological description and dynamical analysis of the Alboran fronts using a realistic simulation at submesoscale resolution. The study is focused on east Alboran fronts emerging within relatively strong flows that separate from the Spanish coast into the basin interior. Despite modest lateral shifting associated with the position of the Alboran anticyclonic gyres and variations in intensity, these fronts present a similar structure and dynamical configuration as the climatological Almeria–Oran front. The statistical analysis of our solution shows that strained-induced frontogenesis is a recurrent submesoscale mechanism associated with these fronts, and the process is assessed in terms of the advective Lagrangian frontogenetic tendencies associated with buoyancy and velocity horizontal gradients. Intermittency in their strength and patterns is indicative of high variability in the occurrence of active frontogenesis in association with the secondary (overturning) circulation across the frontal gradient. As a result, we find many episodes with strong surface fronts that do not have much associated downwelling. Frontogenesis and the associated secondary circulation are further explored during two particular frontal events, both showing strong downwelling of O(1) cm s−1 extending down into the pycnocline. A frontogenetic contribution of turbulent vertical momentum mixing to the secondary circulation is identified in the easternmost region during the cold season, when the dynamics are strongly influenced by the intrusion of the salty Northern Current. The background vertical velocity fields observed during the analyzed events indicate other currents in the submesoscale range, including tidal and topographic internal waves.

© 2021 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: Esther Capó, estherct@g.ucla.edu

Abstract

We present a phenomenological description and dynamical analysis of the Alboran fronts using a realistic simulation at submesoscale resolution. The study is focused on east Alboran fronts emerging within relatively strong flows that separate from the Spanish coast into the basin interior. Despite modest lateral shifting associated with the position of the Alboran anticyclonic gyres and variations in intensity, these fronts present a similar structure and dynamical configuration as the climatological Almeria–Oran front. The statistical analysis of our solution shows that strained-induced frontogenesis is a recurrent submesoscale mechanism associated with these fronts, and the process is assessed in terms of the advective Lagrangian frontogenetic tendencies associated with buoyancy and velocity horizontal gradients. Intermittency in their strength and patterns is indicative of high variability in the occurrence of active frontogenesis in association with the secondary (overturning) circulation across the frontal gradient. As a result, we find many episodes with strong surface fronts that do not have much associated downwelling. Frontogenesis and the associated secondary circulation are further explored during two particular frontal events, both showing strong downwelling of O(1) cm s−1 extending down into the pycnocline. A frontogenetic contribution of turbulent vertical momentum mixing to the secondary circulation is identified in the easternmost region during the cold season, when the dynamics are strongly influenced by the intrusion of the salty Northern Current. The background vertical velocity fields observed during the analyzed events indicate other currents in the submesoscale range, including tidal and topographic internal waves.

© 2021 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: Esther Capó, estherct@g.ucla.edu
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