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| Registros recuperados: 56 | |
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| Bonhommeau, Sylvain; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Rivot, Etienne; Vermard, Youen; Greiner, Eric; Le Pape, Olivier. |
| The migration duration of European eel (Anguilla anguilla) larvae (leptocephali) from the spawning areas in the Sargasso Sea to the European continental shelf remains highly controversial, with estimates varying from 6 months to more than 2 yr. We estimated the fastest migration period and the shortest distance travelled by eel larvae by simulating Lagrangian particles released in the Sargasso Sea and by simulating a range of larval behaviours (fixed-depth drift, vertical diurnal migration and active-depth selection to maximize current velocity). This enabled us to compute (i) a passive drift speed, and (ii) a hypothetic swimming speed needed for European eel larvae to cross the Atlantic in 6 months (i.e., the migration duration estimated from otolith... |
| Tipo: Text |
Palavras-chave: Sargasso Sea; Migration duration; Leptocephali; Lagrangian modelling; Gulf Stream; Fractals; Anguilla. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6865.pdf |
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| Bonhommeau, Sylvain; Le Pape, O.; Gascuel, D.; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Vermard, Youen; Castonguay, M.; Rivot, E.. |
| Using Lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the North Atlantic Ocean, the trans-Atlantic migration of the European eel Anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. Three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. Simulations included mortality hypotheses to estimate a realistic mean migration duration and relative survival of A. anguilla larvae. The mean migration duration was estimated as 21 months and the mortality rate as 3 center dot 8 per year, i.e. < 0 center dot 2% of A. anguilla larvae may typically survive the... |
| Tipo: Text |
Palavras-chave: Migration duration; Leptocephalus mortality; Lagrangian modelling. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6614.pdf |
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| Froyland, G; Padberg, K; England, M; Treguier, Anne-marie. |
| Coherent nondispersive structures are known to play a crucial role in explaining transport in nonautonomous dynamical systems such as ocean flows. These structures are difficult to extract from model output as they are Lagrangian by nature and not revealed by the underlying Eulerian velocity fields. In the last few years heuristic concepts such as finite-time Lyapunov exponents have been used in an attempt to detect barriers to oceanic transport and thus identify regions that trap material such as nutrients and phytoplankton. In this Letter we pursue a novel, more direct approach to uncover coherent regions in the surface ocean using high-resolution model velocity data. Our method is based upon numerically constructing a transfer operator that controls the... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-4349.pdf |
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| Ivchenko, Vladimir O; Treguier, Anne-marie; Best, Se. |
| An energy analysis of the Fine Resolution Antarctic Model (FRAM) reveals the instability processes in the model. The main source of time-mean kinetic energy is the wind stress and the main sink is transfer to mean potential energy. The wind forcing thus helps maintain the density structure. Transient motions result from internal instabilities of the Bow rather than seasonal variations of the forcing. Baroclinic instability is found to be an important mechanism in FRAM. The highest values of available potential energy are found in the western boundary regions as well as in the Antarctic Circumpolar Current (ACC) region. All subregions with predominantly zonal flow are found to be baroclinically unstable. The observed deficit of eddy kinetic energy in FRAM... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44779/44598.pdf |
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| Danabasoglu, Gokhan; Yeager, Steve G.; Bailey, David; Behrens, Erik; Bentsen, Mats; Bi, Daohua; Biastoch, Arne; Boening, Claus; Bozec, Alexandra; Canuto, Vittorio M.; Cassou, Christophe; Chassignet, Eric; Coward, Andrew C.; Danilov, Sergey; Diansky, Nikolay; Drange, Helge; Farneti, Riccardo; Fernandez, E; Fogli, Pier Giuseppe; Forget, Gael; Fujii, Yosuke; Griffies, Stephen M.; Gusev, Anatoly; Heimbach, Patrick; Howard, Armando; Jung, Thomas; Kelley, Maxwell; Large, William G.; Leboissetier, Anthony; Lu, Jianhua; Madec, G; Marsland, Simon J.; Masinam, Simona; Navarram, Antonio; Nurser, A. J. George; Pirani, Anna; Salas Y Melia, David; Samuels, Bonita L.; Scheinert, Markus; Sidorenko, Dmitry; Treguier, Anne-marie; Tsujino, Hiroyuki; Uotila, Petteri; Valcke, Sophie; Voldoire, Aurore; Wangi, Qiang. |
| Simulation characteristics from eighteen global ocean–sea-ice coupled models are presented with a focus on the mean Atlantic meridional overturning circulation (AMOC) and other related fields in the North Atlantic. These experiments use inter-annually varying atmospheric forcing data sets for the 60-year period from 1948 to 2007 and are performed as contributions to the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II). The protocol for conducting such CORE-II experiments is summarized. Despite using the same atmospheric forcing, the solutions show significant differences. As most models also differ from available observations, biases in the Labrador Sea region in upper-ocean potential temperature and salinity distributions, mixed... |
| Tipo: Text |
Palavras-chave: Global ocean-sea-ice modelling; Ocean model comparisons; Atmospheric forcing; Experimental design; Atlantic meridional overturning circulation; North Atlantic simulations. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00164/27525/28368.pdf |
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| Arsouze, Thomas; Treguier, Anne-marie; Peronne, Simon; Dutay, J. -c.; Lacan, F.; Jeandel, C.. |
| Boundary Exchange (BE - exchange of elements between continental margins and the open ocean) has been emphasized as a key process in the oceanic cycle of neodymium (Nd) (Lacan and Jeandel, 2005a). Here, we use a regional eddy-permitting resolution Ocean General Circulation Model (1/4A degrees) of the North Atlantic basin to simulate the distribution of the Nd isotopic composition, considering BE as the only source. Results show good agreement with the data, confirming previous results obtained using the same parameterization of the source in a coarse resolution global model (Arsouze et al., 2007), and therefore the major control played by the BE processes in the Nd cycle on the regional scale. We quantified the exchange rate of the BE, and found that the... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12412/9201.pdf |
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| Hewitt, Helene T.; Roberts, Malcolm; Mathiot, Pierre; Biastoch, Arne; Blockley, Ed; Chassignet, Eric P.; Fox-kemper, Baylor; Hyder, Pat; Marshall, David P.; Popova, Ekaterina; Treguier, Anne-marie; Zanna, Laure; Yool, Andrew; Yu, Yongqiang; Beadling, Rebecca; Bell, Mike; Kuhlbrodt, Till; Arsouze, Thomas; Bellucci, Alessio; Castruccio, Fred; Gan, Bolan; Putrasahan, Dian; Roberts, Christopher D.; Van Roekel, Luke; Zhang, Qiuying. |
| Purpose of Review Assessment of the impact of ocean resolution in Earth System models on the mean state, variability, and future projections and discussion of prospects for improved parameterisations to represent the ocean mesoscale. Recent Findings The majority of centres participating in CMIP6 employ ocean components with resolutions of about 1 degree in their full Earth System models (eddy-parameterising models). In contrast, there are also models submitted to CMIP6 (both DECK and HighResMIP) that employ ocean components of approximately 1/4 degree and 1/10 degree (eddy-present and eddy-rich models). Evidence to date suggests that whether the ocean mesoscale is explicitly represented or parameterised affects not only the mean state of the ocean but also... |
| Tipo: Text |
Palavras-chave: Ocean models; Resolution; Parameterisation; Mesoscale; Submesoscale. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76603/77753.pdf |
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| Levy, Marina; Klein, Patrice; Treguier, Anne-marie. |
| Using a protocol of numerical experiments where horizontal resolution is progressively increased, we show that small-scale (or sub-mesoscale) physics has a strong impact on both mesoscale physics and phytoplankton production/subduction.Mesoscale and sub-mesoscale physics result from the nonlinear equilibration of an unstable baroclinic jet. The biogeochemical context is oligotrophy. The explicitly resolved sub-mesoscales, at least smaller than one fifth of the internal Rossby radius of deformation, reinforce the mesoscale eddy field and contribute to double the primary production and phytoplankton subduction budgets. This enhancement is due to the reinforced mesoscale physics and is also achieved by the small-scale frontal dynamics. This sub-mesoscale... |
| Tipo: Text |
Palavras-chave: Oligotrophy; Phytoplankton production; Vorticity gradient; Eddy field; Mesoscale physics. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-800.pdf |
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| Treguier, Anne-marie; Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Barnier, Bernard; Madec, Gurvan; Molines, Jean-marc; Penduff, Thierry; Czeschel, Lars; Boning, Claus. |
| Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of... |
| Tipo: Text |
Palavras-chave: Ocean model; Thermohaline circulation; North Atlantic; Climate variability; Oceanography. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2199.pdf |
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| Lique, Camille; Treguier, Anne-marie; Scheinert, Markus; Penduff, Thierry. |
| We investigate some aspects of the variability of the Arctic freshwater content during the 1965-2002 period using the DRAKKAR eddy admitting global ocean/sea-ice model (12 km resolution in the Arctic). A comparison with recent mooring sections shows that the model realistically represents the major advective exchanges with the Arctic basin, through Bering, Fram and Davis Straits, and the Barents Sea. This allows the separate contributions of the inflows and outflows across each section to be quantified. In the model, the Arctic freshwater content variability is explained by the sea-ice flux at Fram and the combined variations of ocean freshwater inflow (at Bering) and outflow (at Fram and Davis). At all routes, except trough Fram Strait, the freshwater... |
| Tipo: Text |
Palavras-chave: Fram Strait; Davis Strait; Freshwater flux; Freshwater budget; Arctic Ocean. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6713.pdf |
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| Fox-kemper, Baylor; Adcroft, Alistair; Boening, Claus W.; Chassignet, Eric P.; Curchitser, Enrique; Danabasoglu, Gokhan; Eden, Carsten; England, Matthew H.; Gerdes, Ruediger; Greatbatch, Richard J.; Griffies, Stephen M.; Hallberg, Robert W.; Hanert, Emmanuel; Heimbach, Patrick; Hewitt, Helene T.; Hill, Christopher N.; Komuro, Yoshiki; Legg, Sonya; Le Sommer, Julien; Masina, Simona; Marsland, Simon J.; Penny, Stephen G.; Qiao, Fangli; Ringler, Todd D.; Treguier, Anne-marie; Tsujino, Hiroyuki; Uotila, Petteri; Yeager, Stephen G.. |
| We revisit the challenges and prospects for ocean circulation models following Griffies et al. (2010). Over the past decade, ocean circulation models evolved through improved understanding, numerics, spatial discretization, grid configurations, parameterizations, data assimilation, environmental monitoring, and process-level observations and modeling. Important large scale applications over the last decade are simulations of the Southern Ocean, the Meridional Overturning Circulation and its variability, and regional sea level change. Submesoscale variability is now routinely resolved in process models and permitted in a few global models, and submesoscale effects are parameterized in most global models. The scales where nonhydrostatic effects become... |
| Tipo: Text |
Palavras-chave: Ocean circulation; Model; Parameterization; Climate; Ocean processes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00488/59989/63213.pdf |
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| Barnier, B; Madec, G; Penduff, T; Molines, J; Treguier, Anne-marie; Le Sommer, J; Beckmann, A; Biastoch, A; Boning, C; Dengg, J; Derval, C; Durand, E; Gulev, S; Remy, E; Talandier, Claude; Theetten, Sebastien; Maltrud, M; Mcclean, J; De Cuevas, B. |
| Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4 degrees) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy-enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are... |
| Tipo: Text |
Palavras-chave: Eddy/topography interactions; Partial step topography; Momentum advection scheme; Eddy permitting ocean model; Global ocean. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3514.pdf |
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| Klein, Patrice; Treguier, Anne-marie. |
| The dynamics of the mixed layer in the presence of an embedded geostrophic jet has been investigated using a simple 1 1/2-layer model and a two-dimensional primitive equation model. The jet vorticity induces a spatial variability of the wind-driven inertial motions that can have some important consequences on the mixed-layer dynamics. With a steady wind stress parallel to the front. the main effect is the generation of steady upwellings and downwellings due to the divergence of the mean Ekman drift (as reported by Niiler). With a cross-front wind, however, a dramatic exponential amplification of the inertial oscillations caused by an inertial resonance mechanism is found: this mechanism can increase the inertial waves amplitude by a factor up to 10 within... |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00192/30369/29050.pdf |
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| Talandier, Claude; Deshayes, Julie; Treguier, Anne-marie; Capet, Xavier; Benshila, Rachid; Debreu, Laurent; Dussin, Raphael; Molines, J. -m.; Madec, Gerard. |
| Previous studies have shown that low horizontal resolution (of the order of 1°) ocean models, hence climate models, are not able to adequately represent boundary currents nor mesoscale processes which affect the dynamics and thermohaline circulation of the ocean. While the effect of mesoscale eddies can be parameterized in low resolution models, boundary currents require relatively high horizontal resolution. We clarify the impact of increasing the resolution on the North Atlantic circulation, with emphasis on the Atlantic Meridional Overturning Circulation (AMOC), by embedding a 1/8° nest covering the North Atlantic into a global 1/2° model. Increasing the resolution in the nest leads to regional improvements of the circulation and thermohaline... |
| Tipo: Text |
Palavras-chave: Deep Western Boundary Current; Atlantic Meridional Overturning Circulation; North Atlantic Current; Gulf Stream; Subpolar gyre. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00173/28472/26812.pdf |
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| Lique, Camille; Garric, Gilles; Treguier, Anne-marie; Barnier, Bernard; Ferry, Nicolas; Testut, Charles-emmanuel; Ardhuin, Fanny. |
| The authors investigate the variability of salinity in the Arctic Ocean and in the Nordic and Labrador Seas over recent years to see how the freshwater balance in the Arctic and the exchanges with the North Atlantic have been affected by the recent important sea ice melting, especially during the 2007 sea ice extent minimum. The Global Ocean Reanalysis and Simulations (GLORYS1) global ocean reanalysis based on a global coupled ocean sea ice model with an average of 12-km grid resolution in the Arctic Ocean is used in this regard. Although no sea ice data and no data under sea ice are assimilated, simulation over the 2001-09 period is shown to represent fairly well the 2007 sea ice event and the different components accounting for the ocean and sea ice... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14637/11946.pdf |
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| Klein, Patrice; Treguier, Anne-marie. |
| Rubenstein and Roberts (1986, hereafter RR86) have studied the scattering of inertial waves by a geostrophic jet. The most remarkable effect of the jet is to concentrate near-inertial energy in the negative vorticity region. This effect is due to the horizontal dispersion of near-inértial waves. It is demonstrated by RR86 Using a stratified linearized model. A similar result has been obtaîned by Kunze (1985) using a ray-tracing approach and bas been confirmed by observations (Kunze and Stanford 1984). Another result of RR86 concems the mixed layer depth variations. Their Figs. 3 and 8 show a systematic downwelling in the negative vorticity region of the jet and systematic upwelling in the positive vorticity region. Although large upwellings and... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00254/36565/35119.pdf |
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| Penduff, T; Le Sommer, J; Barnier, B; Treguier, Anne-marie; Molines, J; Madec, G. |
| The combined use of partial steps and of an energy-enstrophy conserving momentum advection scheme was shown by Barnier et al. (2006) to yield substantial improvements in the surface solution of the DRAKKAR 4 global sea-ice/ocean model. The present study extends this investigation below the surface with a special focus on the Atlantic and reveals many improvements there as well: e.g. more realistic path, structure and transports of major currents (Gulf Stream, North Atlantic Current, Confluence region, Zapiola anticyclone), behavior of shedded rings, narrower subsurface boundary currents, stronger mean and eddy flows (MKE and EKE) at depth, beneficial enhancement of cyclonic (anticyclonic) flows around topographic depressions (mountains). Interestingly,... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3712.pdf |
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| Hirschi, Joel J. M.; Barnier, Bernard; Boning, Claus; Biastoch, Arne; Blaker, Adam T.; Coward, Andrew; Danilov, Sergey; Drijfhout, Sybren; Getzlaff, Klaus; Griffies, Steven M.; Hasumi, Hiroyasu; Hewitt, Helene; Iovino, Doroteaciro; Kawasaki, Takao; Kiss, Andrew E.; Koldunov, Nikolay; Marzocchi, Alice; Mecking, Jennifer, V; Moat, Ben; Molines, Jean-marc; Myers, Paul G.; Penduff, Thierry; Roberts, Malcolm; Treguier, Anne-marie; Sein, Dmitry, V; Sidorenko, Dimitry; Small, Justin; Spence, Paul; Thompson, Luanne; Weijer, Wilbert; Xu, Xiaobiao. |
| The Atlantic meridional overturning circulation (AMOC) represents the zonally integrated stream function of meridional volume transport in the Atlantic Basin. The AMOC plays an important role in transporting heat meridionally in the climate system. Observations suggest a heat transport by the AMOC of 1.3 PW at 26 degrees N-a latitude which is close to where the Atlantic northward heat transport is thought to reach its maximum. This shapes the climate of the North Atlantic region as we know it today. In recent years there has been significant progress both in our ability to observe the AMOC in nature and to simulate it in numerical models. Most previous modeling investigations of the AMOC and its impact on climate have relied on models with horizontal... |
| Tipo: Text |
Palavras-chave: Atlantic Meridional Overturning; High-resolution modeling; Mesoscale. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00657/76865/78146.pdf |
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| Registros recuperados: 56 | |
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