An eddy-permitting model of the Atlantic circulation: Evaluating open boundary conditions Auteur(s) : Treguier, Anne-marie Barnier, B De Miranda, A Molines, J Grima, N Imbard, M Madec, G Messager, Christophe Éditeur(s) : American Geophysical Union Résumé : 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. The radiation phase velocities calculated within the algorithm are analyzed. This shows, quite surprisingly, that both the eastern and western boundaries have a similar behavior, regardless of the preferred directions for advection (mainly eastward) and wave propagation (mainly westward). Our results confirm that open boundary algorithms behave differently according to the dynamics of the region considered. The passive boundary condition that Penduff et al. [2000] applied successfully in the north eastern Atlantic does not work in the present South Atlantic model. We emphasize the need for a careful prescription of the climatology at the open boundary, for which a new approach based on synoptic sections is implemented. Journal of Geophysical Union - Research C - Oceans (0148-0227) (American Geophysical Union), 2001-10 , Vol. 106 , N. C10 , P. 22115-22129 Droits : 2001 American Geophysical Union http://archimer.ifremer.fr/doc/2001/publication-454.pdf DOI:10.1029/2000JC000376 http://archimer.ifremer.fr/doc/00000/454/ | Partager |
Two examples of nutritional pathology related to vitamins E and C deficiencies Auteur(s) : Baudin Laurencin, F Messager, J Stephan, Gwendal Éditeur(s) : Actes de colloques Ifremer, Tahiti, French Polynesia, 20 Feb - 4 Mar 1989, n°9, chap. 17, pp.171-181 Résumé : Symptoms recalling a nutritional pathology and more precisely a process of lipid peroxydation were observed during the last years in seabass Dicentrarchus labrax and other fishes cultured in tropical marine condition, Ocyurus chrysurus and Lutjanus analis . They included dark coloration, skin ulceration, lethargy, anorexy, emaciation. Histological examinations showed hepatic fatty degenerative lesions, pancreatitis, muscular degeneration and retinal atrophy. Additional vitamins E and C in the food suppressed that pathological symptoms. The previously evoked clinical or histological signs were not achieved in spite of an increase of the level of hepatic, muscular or blood malondialdehyde and of the conjugated dienes of the perivisceral fat. In the same time, hepatic and muscular tocopherol decreased. These experiments also showed the feasibility and the interest of different analyses in the characterization of such a pathology: hemolysis test and activity of enzymes such as erythrocytic catalase or superoxyde dismutase and plasma glutathione peroxydase. Another nutritional disease is worth describing again, the Granulomatous Hypertyrosinaemia. It was essentially investigated in turbot Scophtalmus maximus but other fish species such as sea bream Chrysophris aurata are often affected. Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/1989/acte-1501.pdf http://archimer.ifremer.fr/doc/00000/1501/ | Partager |