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| Registros recuperados: 56 | |
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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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| 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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| Treguier, Anne-marie; Boebel, O; Barnier, B; Madec, G. |
| A 1/6degrees resolution primitive equation model of the Atlantic circulation is analyzed in the Agulhas region. The model has a realistic level of eddy kinetic energy, and produces anticyclonic Agulhas rings as well as cyclonic structures. In the model as well as in the data, ring trajectories undergo a transition between a turbulent character in the Cape Basin and a steady propagation in the rest of the South Atlantic. The topography of the Walvis Ridge does not seem to play a part in generating this contrast in the model. The model shows that cyclones are primarily generated from the negative shear vorticity side of the Agulhas Current as it leaves the coast, and they are most of the time paired with anticyclones in dipolar or tripolar structures.... |
| Tipo: Text |
Palavras-chave: South Africa; South Atlantic Ocean; Numerical model; Ocean currents; Oceanic eddies; Eddy flux. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-453.pdf |
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| Griffies, Stephen M.; Yin, Jianjun; Durack, Paul J.; Goddard, Paul; Bates, Susan C.; Behrens, Erik; Bentsen, Mats; Bi, Daohua; Biastoch, Arne; Boening, Claus W.; Bozec, Alexandra; Chassignet, Eric; Danabasoglu, Gokhan; Danilov, Sergey; Domingues, Catia M.; Drange, Helge; Farneti, Riccardo; Fernandez, Elodie; Greatbatch, Richard J.; Holland, David M.; Ilicak, Mehmet; Large, William G.; Lorbacher, Katja; Lu, Jianhua; Marsland, Simon J.; Mishra, Akhilesh; Nurser, A. J. George; Salas Y Melia, David; Palter, Jaime B.; Samuels, Bonita L.; Schroeter, Jens; Schwarzkopf, Franziska U.; Sidorenko, Dmitry; Treguier, Anne-marie; Tseng, Yu-heng; Tsujino, Hiroyuki; Uotila, Petteri; Valcke, Sophie; Voldoire, Aurore; Wang, Qiang; Winton, Michael; Zhang, Xuebin. |
| The Palomares Margin, an NNE–SSW segment of the South Iberian Margin located between the Alboran and the Algerian–Balearic basins, is dissected by two major submarine canyon systems: the Gata (in the South) and the Alías–Almanzora (in the North). New swath bathymetry, side-scan sonar images, accompanied by 5 kHz and TOPAS subbottom profiles, allow us to recognize these canyons as Mediterranean examples of medium-sized turbidite systems developed in a tectonically active margin. The Gata Turbidite System is confined between residual basement seamounts and exhibits incised braided channels that feed a discrete deep-sea fan, which points to a dominantly coarse-grained turbiditic system. The Alías–Almanzora Turbidite System, larger and less confined, is a... |
| Tipo: Text |
Palavras-chave: Sea level; CORE global ocean-ice simulations; Steric sea level; Global sea level; Ocean heat content. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29904/28349.pdf |
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| Treguier, Anne-marie; Barnier, B; De Miranda, A; Molines, J; Grima, N; Imbard, M; Madec, Gerard; Messager, Christophe; Reynaud, Thierry; Michel, Sylvain. |
| As part of the French CLIPPER project, an eddy permitting model of the Atlantic circulation has been run for 22 years. The domain has open boundaries at Drake passage and at 30 degreesE, from Africa to Antarctica. The simulated mean circulation, as well as the eddy activity, is satisfactory for a 1/3 degrees model resolution, and the meridional heat transport at 30 degreesS is within the range estimated from observations. We use the "mixed" open boundary algorithm of Barnier et al. [1998], which has both a radiation condition and a relaxation to climatology. The climatological boundary forcing strongly constrains the solution in the whole domain. The model heat balance adjusts through the surface (heat flux retroaction term) more than the open boundaries.... |
| Tipo: Text |
Palavras-chave: General circulation; Numerical modeling; Oceanography. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-454.pdf |
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| Vangriesheim, Annick; Treguier, Anne-marie; Andre, Gael. |
| Current meter measurements have been carried out for 3 years on the continental slope of the Gulf of Guinea, near 7.5 degrees S off the Angola coast. Currents in a water depth of 1300 m over the continental slope show a remarkable biweekly oscillation, bottom intensified, and with currents oriented nearly parallel to the isobaths. With a peak-to-peak amplitude reaching 20-30 cm s(-1) at 30 in above the bottom, this signal is the most energetic at sub-inertial frequencies. Simultaneous measurements deeper on the continental rise (in a water depth of 4000 m) show a more complex signal dominated by lower frequencies, and with less clear polarization. Simple linear topographic wave theories are compared to the observations. A combination of coastal trapped... |
| Tipo: Text |
Palavras-chave: Linear wave model; Current meter measurement; Current oscillation; Continental slope. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1032.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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| Guiavarc'H, Catherine; Treguier, Anne-marie; Vangriesheim, Annick. |
| In the Gulf of Guinea, intraseasonal variability is large at the equator and along the coast. Current data on the continental slope near 7.5° S show very energetic biweekly oscillations at 1300 m depth. A high resolution primitive equation numerical model demonstrates that this deep variability is forced by equatorial winds, through the generation of equatorial Yanai waves that propagate eastward and at depth, and then poleward as coastally-trapped waves upon reaching the coast of Africa. Intraseasonal variability is intensified along the coast of the Gulf of Guinea, especially in the 1020 day period range and at depths between 500 and 1500 m. The kinetic energy distribution is well explained at first order by linear theory. Along the equator, eastward... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6739.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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| Barnier, B.; Blaker, A.t.; Biatosch, A.; Böning, C.w.; Coward, A.; Deshayes, Julie; Hirshi, J.; Le Sommer, J.; Madec, G.; Maze, Guillaume; Molines, J.m.; New, A.; Penduff, T.; Scheinert, M.; Talandier, Claude; Treguier, Anne-marie. |
| DRAKKAR is a consortium of European ocean modelling teams. It was “created to take up the challenges of developing realistic global eddy-resolving/ permitting ocean/sea-ice models, and of building an ensemble of high resolution model hindcasts representing the ocean circulation from the 1960s to present” (quoting the DRAKKAR Group, 2007, in a CLIVAR Exchanges paper where the DRAKKAR strategy was presented for the first time). Now in the second decade of its existence, the DRAKKAR Group is active and thriving, and it is now timely to present recent developments and future plans in this special issue of CLIVAR Exchanges. |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00326/43698/43123.pdf |
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| Berger, Henrick; Treguier, Anne-marie; Perenne, Nicolas; Talandier, Claude. |
| In this study, we analyse the seasonal variability of the sea surface salinity (SSS) for two coastal regions of the Gulf of Guinea from 1995 to 2006 using a high resolution model (1/12°) embedded in a Tropical Atlantic (1/4°) model. Compared with observations and climatologies, our model demonstrates a good capability to reproduce the seasonal and spatial variations of the SSS and mixed layer depth. Sensitivity experiments are carried out to assess the respective impacts of precipitations and river discharge on the spatial structure and seasonal variations of the SSS in the eastern part of the Gulf of Guinea. In the Bight of Biafra, both precipitations and river runoffs are necessary to observe permanent low SSS values but the river discharge has the... |
| Tipo: Text |
Palavras-chave: Gulf of Guinea; Salinity; Modelling; Congo; Bight of Biafra; Mixed layer budget. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30493/29215.pdf |
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| Treguier, Anne-marie; Deshayes, Julie; Lique, Camille; Dussin, Raphael; Molines, Jean-marc. |
| The meridional transport of salt in the Atlantic ocean is an important process for climate, controlling the stability of the meridional overturning circulation. The contribution of transient eddies to this transport is quantified in an eddy resolving North Atlantic model at 1/12 degrees resolution (NATL12), and compared with lower resolution North-Atlantic and global 1/4 degrees models. In NATL12 between 10 degrees N and 40 degrees N, there is a volume loss by evaporation of 0.6 Sverdrups (Sv). The divergence of the eddy flux of salt (normalized by a reference salinity of 34.8) is 0.2 Sv over the region, a significant fraction of the total air-seawater exchange, but it is compensated by an opposite convergent transport of salt by the mean flow, so that the... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19441/17052.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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| 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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| Barrier, Nicolas; Deshayes, Julie; Treguier, Anne-marie; Cassou, Christophe. |
| In the mid 1990’s, the North Atlantic subpolar gyre has shown a dramatic warming event that has been thoroughly investigated from observations and numerical simulations. Some studies suggest that it is due to an interannual, wind-driven weakening and shrinking of the gyre that facilitated the penetration of warm Atlantic Water, the weakening of the gyre being attributed to changes in the North Atlantic Oscillation (NAO) and the East Atlantic Pattern, which are the two dominant modes of atmospheric variability in the North Atlantic. However, other studies suggest that the warming event is due to a decadal, buoyancy-driven strengthening of the meridional overturning circulation and subsequent intensification of the poleward heat transport, in response to the... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00218/32882/31753.pdf |
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| Registros recuperados: 56 | |
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