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| Registros recuperados: 77 | |
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| Sokolovskiy, Mikhail A.; Carton, Xavier. |
| In a two-layer quasi-geostrophic model, the interaction between two opposite-signed hetons (baroclinic vortex pairs) is studied analytically and numerically, for singular and finite-area vortices. For point vortices, using trilinear coordinates, it is shown that the possible evolutions depend on the deformation radius Rd: for large Rd, the layers decouple, vortices pair in each layer and their trajectories are open; for medium Rd, the exchange of opposite-sign partners between layers becomes possible; for small Rd, two other regimes appear: one where hetons remain unaltered during their evolution but follow open trajectories, and one where hetons occupy only a bounded subdomain of space at all times. Conditions for invariant co-rotation of the heton pair... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11351/7924.pdf |
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| Vic, C.; Roullet, Guillaume; Capet, Xavier; Carton, Xavier; Molemaker, Maarten Jeroen; Gula, J.. |
| The Persian Gulf feeds a warm and salty outflow in the Gulf of Oman (northern Arabian Sea). The salt climatological distribution is relatively smooth in the Gulf of Oman, and the signature of a slope current carrying salty waters is difficult to distinguish hundreds of kilometers past the Strait of Hormuz, in contrast to other outflows of the world ocean. This study focuses on the mechanisms involved in the spreading of Persian Gulf Water (PGW) in the Gulf of Oman, using a regional primitive equation numerical simulation. The authors show that the dispersion of PGW occurs through a regime that is distinct from, for example, the one responsible for the Mediterranean outflow dispersion. The background mesoscale eddy field is energetic and participates... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00302/41332/40512.pdf |
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| Morvan, Mathieu; Carton, Xavier. |
| The Omani Coastal Current (OCC) flowing northward along the southern coast of Oman during the summer monsoon is associated with an upwelling system. The mesoscale circulation of the western Arabian Sea is dominated by energetic mesoscale eddies down to about 1000 m depth. They drive the pathways of the upwelling water masses and the Persian Gulf Outflow water. This paper focuses on the sub-mesoscale frontal dynamics in the OCC by analyzing the results from a regional realistic numerical simulation performed with a primitive equation model. Off the Omani coast, the interaction between the upwelling fronts and the mesoscale eddies triggers the frontogenesis at play in the surface mixed layer during the summer monsoon. In spring, sub-mesoscale eddies are... |
| Tipo: Text |
Palavras-chave: Sub-mesoscale; Fronts; Instabilities. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00623/73483/72784.pdf |
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| Carton, Xavier; Ciani, Daniele; Verron, J.; Reinaud, J.; Sokolovskiy, M.. |
| The merger of two identical surface temperature vortices is studied in the surface quasi-geostrophic model. The motivation for this study is the observation of the merger of submesoscale vortices in the ocean. Firstly, the interaction between two point vortices, in the absence or in the presence of an external deformation field, is investigated. The rotation rate of the vortices, their stationary positions and the stability of these positions are determined. Then, a numerical model provides the steady states of two finite-area, constant-temperature, vortices. Such states are less deformed than their counterparts in two-dimensional incompressible flows. Finally, numerical simulations of the nonlinear surface quasi-geostrophic equations are used to... |
| Tipo: Text |
Palavras-chave: Shear/strain flow; Steady states; Vortex merger; Numerical model; Surface quasi-geostrophy; Critical distance. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00323/43460/42864.pdf |
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| Ciani, Daniele; Carton, Xavier; Aguiar, A. C. Barbosa; Peliz, A.; Bashmachnikov, I.; Ienna, F.; Chapron, Bertrand; Santoleri, R.. |
| We study the surface signatures of Mediterranean water eddies (Meddies) in the context of a regional, primitive equations model simulation (using the Regional Oceanic Modeling System, ROMS). This model simulation was previously performed to study the mean characteristics and pathways of Meddies during their evolution in the Atlantic Ocean. The advantage of our approach is to take into account different physical mechanisms acting on the evolution of Meddies and their surface signature, having full information on the 3D distribution of all physical variables of interest. The evolution of around 90 long-lived Meddies (whose lifetimes exceeded one year) was investigated. In particular, their surface signature was determined in sea-surface height, temperature... |
| Tipo: Text |
Palavras-chave: Subsurface Anticyclones; Mediterranean water eddies; Satellite detection. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00405/51672/52220.pdf |
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| Reinaud, Jean N.; Carton, Xavier; Dritschel, David G.. |
| We investigate the interaction between a heton and a current generated by a filament of buoyancy anomaly at the surface. Hetons are baroclinic dipoles consisting of a pair of vortices of opposite signs lying at different depths. Such structures have self-induced motion whenever the pair of vortices are offset horizontally. A surface buoyancy filament generates a shear flow since the density perturbation locally modifies the pressure field. The vertical shear induced by the filament offsets the vortices of the heton if vertically aligned initially. Moreover, if the vortex nearer the surface is in adverse horizontal shear with the buoyancy filament, the heton tends to move towards the filament. Conversely, if the upper vortex is in cooperative horizontal... |
| Tipo: Text |
Palavras-chave: Quasi-geostrophy; Surface buoyancy anomaly; Vortex dynamics. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71253/69631.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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| Capuano, Tonia Astrid; Speich, Sabrina; Carton, Xavier; Blanke, Bruno. |
| The turbulent processes in the Cape Basin, the southeasternmost gate of the Atlantic Ocean, play a key role in the transport and mixing of upper to intermediate water masses entering the area from the Indian Ocean, making them especially relevant for the Indo-Atlantic transfer of heat and salt. In this paper, two numerical simulations at different horizontal resolutions are used to study mesoscale and submesoscale dynamics, their phenomenology, their evolution, and their impact on the local water masses. Submesoscale processes seasonally affect both, the upper and intermediate layers, but there are clear dynamical differences between the two layers. Several types of instabilities underline this spatial and temporal variability. Near the surface, mixed... |
| Tipo: Text |
Palavras-chave: Meso- and submesoscale dynamics; Cape Basin water masses; Indo-Atlantic exchange. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71247/69618.pdf |
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| Perruche, Coralie; Riviere, Pascal; Pondaven, Philippe; Carton, Xavier. |
| This paper aims at studying analytically the functioning of a very simple ecosystem model with two phytoplankton species. First, using the dynamical system theory, we determine its nonlinear equilibria, their stability and characteristic timescales with a focus on phytoplankton competition. Particular attention is paid to the model sensitivity to parameter change. Then, the influence of vertical mixing and sinking of detritus on the vertically-distributed ecosystem model is investigated. The analytical results reveal a high diversity of ecosystem structures with fixed points and limit cycles that are mainly sensitive to variations of light intensity and total amount of nitrogen matter. The sensitivity to other parameters such as remineralisation, growth... |
| Tipo: Text |
Palavras-chave: Water mixing; Dynamical system; Phytoplankton; Competition; Ecosystem; Modelling. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7334.pdf |
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| Bashmachnikov, I.; Neves, F.; Nascimento, A.; Medeiros, J.; Ambar, I.; Dias, J.; Carton, Xavier. |
| The present study defines new interpolation functions for hydrological data. These functions are applied to generate climatological maps of temperature-salinity distribution with a 25 m depth interval and a 30 km space interval (MEDTRANS data set). The data undergo rigorous initial data quality control, having passed several filtering procedures. The gridding is done on neutral density surfaces, which allows better representation of thermohaline fronts for the same gridding radius. The multi-pass Barnes optimum interpolation procedure with spatially variable size of the gridding window is used. The shape of the window accounts for the dominant along-isobath direction of water mass transport over steeply sloping topography. A local ratio of topographic to... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00266/37729/35735.pdf |
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| Morvan, Mathieu; Carton, Xavier; Corréard, Stéphanie; Baraille, Rémy. |
| We have investigated the surface and subsurface submesoscale dynamics in the Gulf of Aden and the Gulf of Oman. Our results are based on the analyses of regional numerical simulations performed with a primitive equation model (HYCOM) at submesoscale permitting horizontal resolution. A model zoom for each gulf was embedded in a regional mesoscale-resolving simulation. In the Gulf of Aden and the Gulf of Oman, the interactions of mesoscale structures and fronts instabilities form submesoscale eddies and filaments. Rotational energy spectra show that the Gulf of Aden has a higher ratio of submesoscale to mesocale energy than the Gulf of Oman. Fast waves (internal gravity waves, tidal waves, Kelvin waves) and slow waves (Rossby waves) were characterized via... |
| Tipo: Text |
Palavras-chave: Submesoscale instabilities; Eddies and waves; Upwelling fronts. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00645/75698/76603.pdf |
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| Ciani, Daniele; Carton, Xavier; Verron, Jacques. |
| Vortex merger is a phenomenon characterizing the whole class of geophysical vortices, from atmospheric storms and large oceanic eddies up to small scale turbulence. Here we focus on the merger of subsurface oceanic anticyclones in an idealized primitive equations model. This study has been motivated by past and recent observations of colliding lens-like anticyclones off of Gibraltar Strait. The critical conditions for merger (critical merger distance and time needed for merger) are determined. We will show that the predictions of classical two-dimensional merger are not verified for subsurface isolated vortices. For instance, critical merger distances will be reduced because of the vortex potential vorticity (PV) structure. The post-merger characteristics... |
| Tipo: Text |
Palavras-chave: Subsurface isolated vortices; Peddies; Meddies; Vortex merger. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00314/42563/44982.pdf |
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| Dulaquais, Gabriel; Boye, Marie; Middag, Rob; Owens, Stephanis; Puigcorbe, Viena; Buesseler, Ken; Masque, Pere; De Baar, Hein J. W.; Carton, Xavier. |
| Dissolved cobalt (DCo; <0.2 µm; 14 to 93 pM) and the apparent particulate cobalt (PCo; >0.2 µm; <1 to 15 pM) were determined in the upper water column (<1000 m) of the western Atlantic Ocean along the GEOTRACES-A02 section (64°N to 50°S). The lowest DCo concentrations, typical of a nutrient-type distribution were observed in surface waters of the subtropical domains. Strong linear relationships between DCo and phosphate (P) as well as meridional gradients of decreasing DCo from high latitudes were characterized and both linked to the Co biological requirement. External sources such as the Amazon and the atmospheric deposition were found to contribute significantly (>10%) to the DCo stock of the mixed layer in the equatorial and north... |
| Tipo: Text |
Palavras-chave: Cobalt; Biogeochemistry; Atlantic Ocean; Chemical Oceanography; GEOTRACES. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00241/35222/33732.pdf |
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| Capuano, Tonia Astrid; Speich, Sabrina; Carton, Xavier; Laxenaire, Remi. |
| This study evaluates the capability of eddy-permitting regional ocean models to reproduce the interocean exchange south of Africa. In this highly turbulent region, we show that the vertical structure of the horizontal flows need to be appropriately resolved to realistically advect thermocline water masses into the South Atlantic. Our results point out that a grid-spacing of 1/24 degrees on the horizontal and 50 m on the vertical homogeneously distributed are required to account for a correct transport of surface and subsurface water masses properties and their in-route transformation by mixing. Preliminary Lagrangian analyses highlight the primary role of the upper-ocean mesoscale eddies on water masses transport and fate, with a particular emphasis on... |
| Tipo: Text |
Palavras-chave: Eddy dynamics; Indo-Atlantic exchange; AAIW. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71245/69616.pdf |
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| Pous, Stephane; Carton, Xavier; Lazure, Pascal. |
| In October and early November 1999, the GOGP99 experiment collected hydrological, currentmeter, tide recorder, thermistor and drifting buoy data near the Strait of Hormuz. Data analysis provides the water mass structure in the Strait: Persian Gulf Water (PGW) core is banked against the Omani coast, while Indian Ocean Surface Water (IOSW) lies near the Iranian coast. These water masses are most often covered by a homogeneous surface layer. Thermohaline characteristics of the PGW core decrease substantially downstream, from the Persian/Arabian Gulf to the Gulf of Oman. PGW and IOSW thermohaline characteristics and distribution also exhibit notable changes at periods shorter than a month as shown by repeated hydrological sections. The tidal signal measured... |
| Tipo: Text |
Palavras-chave: Oceanography; Hydrology; Hormuz. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-389.pdf |
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| L'Hegaret, Pierre; Carton, Xavier; Ambar, Isabel; Menesguen, Claire; Hua, Bach Lien; Cherubin, Laurent; Aguiar, Ana; Le Cann, Bernard; Daniault, Nathalie; Serra, Nuno. |
| A collision of Mediterranean Water dipoles in the Gulf of Cadiz is studied here, using data from the MedTop and Semane experiments. First, a Mediterranean Water eddy (meddy) was surveyed hydrologically in November 2000 southwest of Cape Saint Vincent. Then, this meddy drifted northeastward from this position, accompanied by a cyclone (detected only via altimetry), thus forming a first dipole. In February 2001, a dipole of Mediterranean Water was measured hydrologically just after its formation near Portimão Canyon. This second dipole drifted southwestward. The western and eastern meddies had hydrological radii of about 22 and 25 km, respectively, with corresponding temperature and salinity maxima of (13.45°C, 36.78) and (11.40°C, 36.40). Rafos float... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00204/31565/29986.pdf |
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| Quentel, Elise; Carton, Xavier; Gutscher, Marc-andre. |
| Hydrological and marine seismic data, collected in the Gulf of Cadiz (respectively in July 1999, 2000, 2001 and 2002, and in April 2000 and 2001) are analysed to reveal the various structures of Mediterranean Water (MW). Both the hydrological and seismic data clearly identify the MW undercurrents on the Iberian slope, detached MW eddies (meddies and a cyclone) and smaller fragments of MW (filaments and small eddies). Seismic reflectivity and synthetic reflectivity computed from hydrology, indicate that strong acoustic reflectors, associated with 8 - 64 m thick homogeneous water layers, are found above and below meddies and filaments, around the MW undercurrents, but mostly in the lower part of cyclones and below submesoscale eddies. Reflectors are also... |
| Tipo: Text |
Palavras-chave: Mediterranean Water; Eddies; Undercurrent; Layering; Hydrological Data; Seismic Reflectivity; Submesoscale Structures. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00129/24006/21962.pdf |
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| Registros recuperados: 77 | |
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