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Morel, Yves; Gula, Jonathan; Ponte, Aurelien. |
Taking advantage of alternative expressions for potential vorticity (PV) in divergence forms, we derive balances between volume integral of PV and boundary conditions, that are then applied to practical computations of PV: • we propose a new method for diagnosing the Ertel potential vorticity from model output, that preserves the balances; • we show how the expression of PV can be derived in general coordinate systems. This is here emphasised with isopycnic coordinates by generalising the PV expression to the general Navier-Stokes equations; • we propose a generalised derivation for the Haynes-McIntyre impermeability theorem, which highlights the role of the bottom boundary condition choice (e.g. no-slip vs free-slip) and mixing near the bottom boundary... |
Tipo: Text |
Palavras-chave: Potential vorticity; Boundary conditions; General circulation; Vortex; Fronts; Boundary layers. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00494/60525/63988.pdf |
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Gerin, R.; Poulain, P. -m.; Taupier-letage, Isabelle; Millot, C.; Ben Ismail, S.; Sammari, Cherif. |
Within the framework of the EGITTO/EGYPT programs, the spatial structure and the temporal variability of the surface circulation in the eastern basin of the Mediterranean Sea was studied with satellite-tracked drifters. A total of 97 drifters drogued to 15-m nominal depth were released between September 2005 and March 2007, regularly along ship-of-opportunity routes in the Sicily Channel and within specific structures during dedicated campaigns in the Levantine sub-basin. This study complements previous ones in the former and in the Ionian, but it is the first one in the latter. After editing and low-pass filtering, the drifter trajectories were used to estimate pseudo-Eulerian statistics: mean current, variance ellipses, mean and eddy kinetic energies. A... |
Tipo: Text |
Palavras-chave: Lagrangian drifters; General circulation; Undrogued drifters; Sea; Variability; Features; Basin; Model; Dynamics. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00204/31480/29891.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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Civitarese, G; Crise, A; Crispi, G; Mosetti, R. |
In this work the description of the interaction between the general circulation and the nitrogen cycle in the Ionian Sea is considered. Firstly, an analysis is made of nitrate data collected during POEM-BC cruises in October 1991 and April 1992; then a numerical experiment based on a coupled hydrodynamic ecomodel is presented. The model results relative to the periods corresponding to the cruises are discussed. The ecomodel is climatological and represents an aggregated description of the nitrogen cycle in terms of inorganic nitrogen, phytoplankton and detritus. The numerical results as nitrogen distributions, fluxes and primary production are presented. A strong dependence of nitrogen distribution on circulation emerges both from the observational data... |
Tipo: Text |
Palavras-chave: Ionian Sea; Nitrogen cycle; General circulation; Ecomodel; Primary production. |
Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20729/18366.pdf |
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