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| Registros recuperados: 16 | |
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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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| Fernández-castro, Bieito; Evans, Dafydd Gwyn; Frajka-williams, Eleanor; Vic, Clement; Naveira-garabato, Alberto C.. |
| A four-month glider mission was analyzed to assess turbulent dissipation in an anticyclonic eddy at the western boundary of the subtropical North Atlantic. The eddy (radius ≈ 60 km) had a core of low potential vorticity between 100–450 m, with maximum radial velocities of 0.5 m s−1 and Rossby number ≈ −0.1. Turbulent dissipation was inferred from vertical water velocities derived from the glider flight model. Dissipation was suppressed in the eddy core (ε ≈ 5×10−10 W kg−1) and enhanced below it (> 10−9 W kg−1). Elevated dissipation was coincident with quasi-periodic structures in the vertical velocity and pressure perturbations, suggesting internal waves as the drivers of dissipation. A heuristic ray-tracing approximation was used to investigate the... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00615/72734/71841.pdf |
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| Vic, Clement; Naveira Garabato, Alberto C.; Green, J. A. Mattias; Waterhouse, Amy F.; Zhao, Zhongxiang; Melet, Angelique; De Lavergne, Casimir; Buijsman, Maarten C.; Stephenson, Gordon R.. |
| Turbulent mixing in the ocean is key to regulate the transport of heat, freshwater and biogeochemical tracers, with strong implications for Earth's climate. In the deep ocean, tides supply much of the mechanical energy required to sustain mixing via the generation of internal waves, known as internal tides, whose fate-the relative importance of their local versus remote breaking into turbulence-remains uncertain. Here, we combine a semi-analytical model of internal tide generation with satellite and in situ measurements to show that from an energetic viewpoint, small-scale internal tides, hitherto overlooked, account for the bulk (>50%) of global internal tide generation, breaking and mixing. Furthermore, we unveil the pronounced geographical variations... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00601/71275/69674.pdf |
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| Vic, Clement; Roullet, Guillaume; Carton, Xavier; Capet, X.. |
| The Great Whirl (GW) is a persistent anticyclonic mesoscale eddy that is observed seasonally in the Arabian Sea during a period embedding the 3 months of the southwest monsoon (June–July–August) at a quasi-steady location. Its dynamics remain unclear despite it being one of the largest coherent vortices in the world ocean. Realistic regional numerical experiments using ROMS are performed to investigate the life cycle of the GW, which is not well resolved by sparse available in situ measurements in the region. Using a set of sensitivity experiments and an accurate temporal characterization of the eddy properties (including position, radius, depth, and vorticity) we (i) confirm the role of basin-scale downwelling Rossby waves in the GW generation, (ii)... |
| Tipo: Text |
Palavras-chave: Arabian Sea; Indian Ocean; Great Whirl; Mesoscale dynamics; ROMS; Rossby waves. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32197/30631.pdf |
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| L'Hegaret, P.; Duarte, R.; Carton, Xavier; Vic, Clement; Ciani, Daniele; Baraille, R.; Correard, S.. |
| The Arabian Sea and Sea of Oman circulation and water masses, subject to monsoon forcing, reveal a strong seasonal variability and intense mesoscale features. We describe and analyze this variability and these features, using both meteorological data (from ECMWF reanalyses), in situ observations (from the ARGO float program and the GDEM - Generalized Digital Environmental mode - climatology), satellite altimetry (from AVISO) and a regional simulation with a primitive equation model (HYCOM - the Hybrid Coordinate Ocean Model). The model and observations display comparable variability, and the model is then used to analyze the three-dimensional structure of eddies and water masses with higher temporal and spatial resolutions than the available observations.... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00286/39690/38149.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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| Cimoli, Laura; Caulfield, Colm‐cille P.; Johnson, Helen L.; Marshall, David P.; Mashayek, Ali; Naveira Garabato, Alberto C.; Vic, Clement. |
| There have been recent advancements in the quantification of parameters describing the proportion of internal tide energy being dissipated locally and the “efficiency” of diapycnal mixing, i.e. the ratio of the diapycnal mixing rate to the kinetic energy dissipation rate. We show that oceanic tidal mixing is non‐trivially sensitive to the co‐variation of these parameters. Varying these parameters one at the time can lead to significant errors in the patterns of diapycnal mixing driven upwelling and downwelling, and to the over and under estimation of mixing in such a way that the net rate of globally‐integrated deep circulation appears reasonable. However, the local rates of upwelling and downwelling in the deep ocean are significantly different when both... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00595/70675/68873.pdf |
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| Morvan, Mathieu; L'Hégaret, Pierre; Carton, Xavier; Gula, Jonathan; Vic, Clement; Sokolovskiy, Mikhail; Koshel, Konstantin. |
| The Persian Gulf Water and Red Sea Water are salty and dense waters recirculating at subsurface in the Gulf of Oman and the Gulf of Aden respectively, under the influence of mesoscale eddies which dominate the surface flow in both semi-enclosed basins. In situ measurements combined with altimetry indicate that the Persian Gulf Water is driven by mesoscale eddies in the form of filaments and submesoscale structures. In this paper, we study the formation and the life cycle of intense submesoscale vortices and their impact on the spread of Persian Gulf Water and Red Sea Water. We use a three-dimensional hydrostatic model with submesoscale-resolving resolution to study the evolution of submesoscale vortices. Our configuration is an idealized version of the... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00589/70153/68140.pdf |
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| Balem, Kevin; Vic, Clement. |
| Le projet RREX propose une étude approfondie des interactions entre les courants océaniques et la dorsale de Reykjanes afin de documenter la circulation autour et sur celle-ci. Le projet repose en partie sur un vaste ensemble de données hydrographiques in-situ. Celui-ci combine des données issues de CTD, d'XBT, de flotteurs Argo et de sept mouillages instrumentés. Ces derniers sont constitués d'une centaine d'instruments (capteurs CTD, capteurs de température, courantomètres/ADCP) déployés entre 2015 et 2017 sur 7 lignes de mouillages entre 300 et 2300m. Nous présentons ici 2 outils développés au Laboratoire d'Océanographie Physique et Spatiale pour prétraiter et analyser ces séries temporelles. Pour illustrer ce travail, nous présentons également quelques... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00689/80091/83145.pdf |
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| Vic, Clement; Capet, Xavier; Roullet, Guillaume; Carton, Xavier; ,. |
| Despite its climatic and ecosystemic significance, the coastal upwelling that takes place off Oman is not well understood. A primitive-equation, regional model forced by climatological wind stress is used to investigate its dynamics and to compare it with the better-known Eastern Boundary Upwellings (EBUs). The solution compares favorably with existing observations, simulating well the seasonal cycles of thermal structure, surface circulation (mean and turbulent), and sea-surface temperature (SST). There is a 1.5-month lag between the maximum of the upwelling-favorable wind-stress-curl forcing and the oceanic response (minima in sea-surface height and SST), which we attribute to onshore-propagating Rossby waves. A southwestward-flowing undercurrent... |
| Tipo: Text |
Palavras-chave: Oman; Upwelling; Arabian sea; ROMS; Rossby waves; Eddy kinetic energy. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00382/49350/49752.pdf |
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| Registros recuperados: 16 | |
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