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| Lavergne, C.; Vic, Clement; Madec, G; Roquet, F.; Waterhouse, A. F.; Whalen, C. B.; Cuypers, Y.; Bouruet‐aubertot, P.; Ferron, Bruno; Hibiya, T.. |
| Vertical mixing is often regarded as the Achilles' heel of ocean models. In particular, few models include a comprehensive and energy‐constrained parameterization of mixing by internal ocean tides. Here, we present an energy‐conserving mixing scheme which accounts for the local breaking of high‐mode internal tides and the distant dissipation of low‐mode internal tides. The scheme relies on four static two‐dimensional maps of internal tide dissipation, constructed using mode‐by‐mode Lagrangian tracking of energy beams from sources to sinks. Each map is associated with a distinct dissipative process and a corresponding vertical structure. Applied to an observational climatology of stratification, the scheme produces a global three‐dimensional map of... |
| Tipo: Text |
Palavras-chave: Ocean mixing; Internal tides; Parameterization; Energy dissipation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73573/72943.pdf |
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| Dushaw, Brian; Gaillard, Fabienne; Terre, Thierry. |
| An acoustic propagation experiment over 308-km range conducted in the Canary Basin in 1997–1998 was used to assess the ability of ocean acoustic tomography to measure the flux of Mediterranean water and Meddies. Instruments on a mooring adjacent to the acoustic path measured the southwestward passage of a strong Meddy in temperature, salinity, and current. Over nine months of transmissions, the acoustic arrival pattern was an initial broad stochastic pulse varying in duration by 250 to 500 ms, followed eight stable, identified ray arrivals. Small-scale sound speed fluctuations from Mediterranean water parcels littered around the sound channel axis caused acoustic scattering. Internal waves contributed more modest acoustic scattering. Based on simulations,... |
| Tipo: Text |
Palavras-chave: Meddy; Acoustic tomography; Canary Basin; Mediterranean water; Internal tides. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00404/51519/52112.pdf |
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| Bouruet-aubertot, Pascale; Cuypers, Yannis; Ferron, Bruno; Dausse, Denis; Menage, Olivier; Atmadipoera, Agus; Jaya, Indra. |
| Microstructure measurements were performed along two sections through the Halmahera Sea and the Ombai Strait and at a station in the deep Banda Sea. Contrasting dissipation rates (𝜖) and vertical eddy diffusivities (K z ) were obtained with depth-averaged ranges of ∼[9×10−10−10−5] W kg− 1 and of ∼[1×10−5−2×10−3] m2 s− 1, respectively. Similarly, turbulence intensity, I=ϵ/(νN2) with ν the kinematic viscosity and N the buoyancy frequency, was found to vary seven orders of magnitude with values up to 107. These large ranges of variations were correlated with the internal tide energy level, which highlights the contrast between regions close and far from internal tide generations. Finescale parameterizations of 𝜖 induced by the breaking of... |
| Tipo: Text |
Palavras-chave: Turbulence; Internal tides; Vertical mixing; Parameterization; Indonesian seas; Microstructure measurements. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55240/56792.pdf |
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| Maraldi, Claire; Lyard, Florent; Testut, Laurent; Coleman, Richard. |
| A barotropic tidal model, with a parameterization term to account for the internal wave drag energy dissipation, is used to examine areas of possible M(2) internal tide generation in the Kerguelen Plateau region. Barotropic energy flux and a distribution of wave drag dissipation are computed. The results suggest important conversion of barotropic energy into baroclinic tide generation over the northern Kerguelen Plateau shelf break, consistent with a theoretical criterion based on ocean stratification, tidal forcing frequency, and bathymetric gradients. The sea surface height signatures of time-coherent internal tides are studied using TOPEX/Poseidon and Jason-1 altimeter data, whose ascending tracks cross nearly perpendicular to the eastern and western... |
| Tipo: Text |
Palavras-chave: Internal tides; Kerguelen Plateau; Altimetry; Barotropic tides. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00144/25564/23709.pdf |
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| Lahaye, Noe; Gula, Jonathan; Roullet, Guillaume. |
| Internal tides are a predominant source of high‐frequency variability and diapycnal mixing in the ocean. Understanding their dynamics and lifecycle is necessary to better understand their role in the ocean circulation. In this paper, we describe and quantify internal tide generation, propagation and dissipation in a sector of the North Mid‐Atlantic Ridge, using high‐resolution numerical simulations with realistic bathymetry and stratification. We show that the generation and dissipation of internal tides, as well as the distribution of internal tides amongst vertical modes, exhibit high spatial variability. We find that topographic scattering leads to a significant transfer of energy towards high vertical modes and thereby enhances internal tide... |
| Tipo: Text |
Palavras-chave: Energy dissipation & Mixing; Internal tides; Internal waves; Topographic scattering. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00658/77003/78259.pdf |
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| Cai, Yang; Guo, Pu; Fang, Wendong. |
| 20-day in-situ ADCP current and CTD data are used to investigate the characteristics and energy of the internal tides in the northern South China Sea (NSCS). The results show that the O1, K1, M2 and S2 constituents of internal tides are energetic and diurnal constituents (O1 and K1) are dominating. In the observational period, the current vectors of these four constituents all rotate clockwise and the maximum semi-major axe of internal tidal ellipses is more than 14 cm/s. The variation of ocean temperature shows that the internal tides present obvious quasi-diurnal oscillation and the average amplitude reaches 50 m. Furthermore, these internal tides carry high energy and appear to be intermittent. The maximum values of KE (PE) during the observational... |
| Tipo: Journal Contribution |
Palavras-chave: Internal tides; In situ measurements; Energy. |
| Ano: 2012 |
URL: http://hdl.handle.net/1834/5844 |
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| Xie, X. H.; Cuypers, Y.; Bouruet-aubertot, P.; Ferron, Bruno; Pichon, Annick; Lourenco, A.; Cortes, Norbert. |
| Microstructure and fine-scale measurements collected in the central Bay of Biscay during the MOUTON experiment are analyzed to investigate the dynamics of internal waves and associated mixing. Large-amplitude internal tides (ITs) that excite internal solitary waves (ISWs) in the thermocline are observed. ITs are dominated by modes 3 and 4, while ISWs projected on mode 1 that is trapped in the thermocline. Therein, ITs generate a persistent narrow shear band, which is strongly correlated with the enhanced dissipation rate in the thermocline. This strong dissipation rate is further reinforced in the presence of ISWs. Dissipation rates during the period without ISWs largely agree with the MacKinnon-Gregg scaling proposed for internal wavefields dominated by a... |
| Tipo: Text |
Palavras-chave: Internal tides; Solitary waves; Turbulence; Bay of Biscay. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00151/26232/24299.pdf |
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| Buijsman, Maarten C.; Stephenson, Gordon R.; Ansong, Joseph K.; Arbic, Brian K.; Green, J.a. Mattias; Richman, James G.; Shriver, Jay F.; Vic, Clement; Wallcraft, Alan J.; Zhao, Zhongxiang. |
| The effects of horizontal resolution and wave drag damping on the semidiurnal M tidal energetics are studied for two realistically-forced global HYbrid Coordinate Ocean Model (HYCOM) simulations with 41 layers and horizontal resolutions of 8 km (; H12) and 4 km (; H25). In both simulations, the surface tidal error is minimized by tuning the strength of the linear wave drag, which is a parameterization of the surface-tide energy conversion to the unresolved baroclinic wave modes. In both simulations the M surface tide error with TPXO8-atlas, an altimetry constrained model, is 2.6 cm. Compared to H12, the surface tide energy conversion to the resolved vertical modes is increased by 50% in H25. This coincides with an equivalent reduction in the tuned loss of... |
| Tipo: Text |
Palavras-chave: Numerical models; Internal tides; Wave damping; Vertical modes. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00640/75199/75332.pdf |
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| González-haro, Cristina; Ponte, Aurelien; Autret, Emmanuelle. |
| The expected amplitude of fixed-point sea surface temperature (SST) fluctuations induced by barotropic and baroclinic tidal flows is estimated from tidal current atlases and SST observations. The fluctuations considered are the result of the advection of pre-existing SST fronts by tidal currents. They are thus confined to front locations and exhibit fine-scale spatial structures. The amplitude of these tidally induced SST fluctuations is proportional to the scalar product of SST frontal gradients and tidal currents. Regional and global estimations of these expected amplitudes are presented. We predict barotropic tidal motions produce SST fluctuations that may reach amplitudes of 0.3 K. Baroclinic (internal) tides produce SST fluctuations that may reach... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Satellite observations; Tidal currents; Internal tides. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00589/70075/68048.pdf |
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