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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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| Boukthir, M; Verron, J; Barnier, B. |
| This paper examines how satellite altimeter and scatterometer measurements could be jointly used in a numerical ocean model in an attempt to simulate a realistic ocean circulation. The aim of the study is to determine quantitatively how sensitive the efficiency of the assimilation process may be to the variability of the wind stress curl and to evaluate the ability of the Topex/Poseidon altimetric data to correct for the sampling of scatterometer wind data that is to be provided by the forthcoming ERS 1 and NSCAT satellite missions. The model is quasigeostrophic, eddy-resolving and multi-layered, and is applied to the prognostic description of the mid-latitude ocean circulation in a schematic box ocean. Satellite altimeter data are simulated from model... |
| Tipo: Text |
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| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00101/21239/18854.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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| Penduff, T; Colin De Verdiere, Emmanuel; Barnier, B. |
| The mean circulation of the eastern North Atlantic is investigated using a regional 0.8 degrees x cos(latitude)-resolution configuration of the SPEM primitive equation sigma coordinate model, forced by seasonal and monthly surface fluxes. The computational domain is surrounded by three self-adapting open boundaries which evacuate the outgoing perturbations and laterally control the baroclinic modes in inflow regions, but let the model adjust the barotropic Mode to a large extent. The final solution is stable and reproduces most features of the basin's mean circulation well: A realistic Azores Current, the observed paths and transports of subpolar currents, of the branches of the North Atlantic Current, of the intergyre zone modal and intermediate water... |
| Tipo: Text |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00000/10274/9577.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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| 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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