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| Menkes, Christophe; Kennan, Sc; Flament, Pierre; Dandonneau, Y; Masson, S; Biessy, B; Marchal, E; Eldin, G; Grelet, J; Montel, Y; Morliere, A; Lebourges-dhaussy, A; Moulin, C; Champalbert, G; Herbland, Alain. |
| [1] The equatorial Pacific and Atlantic oceans exhibit remarkable meridional undulations in temperature and chlorophyll fronts visible from space over thousands of kilometers and often referred to as tropical instability waves. Here, we present new observations of an ecosystem ranging through three trophic levels: phytoplankton, zooplankton and small pelagic fish whirling within a tropical vortex of the Atlantic ocean and associated with such undulations. Cold, nutrient and biologically rich equatorial waters are advected northward and downward to form sharp fronts visible in all tracers and trophic levels. The equatorward recirculation experiences upwelling at depth, with the pycnocline and ecosystem progressively moving toward the surface to reconnect... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10049/9584.pdf |
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| Gouriou, Y; Andrie, C; Bourles, B; Freudenthal, S; Arnault, S; Aman, A; Eldin, G; Du Penhoat, Y; Baurand, F; Gallois, F; Chuchla, R. |
| In the Atlantic Ocean, the northward export of warm surface water is compensated by a southward flow of cold North Atlantic Deep Water (NADW). The NADW is transported southward along the American continental margin within the Deep Western Boundary Current (DWBC). Some tracer and float observations have shown that part of the DWBC water flows eastward along the equator. Here we present three meridional velocity sections which give an instantaneous image of the top-to-bottom zonal circulation along the equatorial Atlantic. They reveal the presence of Equatorial Deep Jets (EDJs) between 1 degrees 30'N and 1 degrees 30'S, alternating eastward-westward currents with short vertical scale, surrounded by columns of eastward currents (the Extra Equatorial Jets or... |
| Tipo: Text |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00000/10369/9567.pdf |
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| Bourles, B; D'Orgeville, Marc; Eldin, G; Gouriou, Y; Chuchla, R; Dupenhoat, Y; Arnault, S. |
| Eastward currents in the thermocline and subthermocline layers of the tropical Atlantic Ocean are described using observations obtained during two boreal summer cruises covering the whole equatorial basin. The analysis focuses on the eastward evolution of zonal currents in the thermocline and sub-thermocline. The Equatorial Undercurrent is not found close to the African coast in boreal summer 2000, maybe because of interannual variability. As observed in the Pacific, the South and North Equatorial Undercurrents are shown to shift poleward from west to east, and the two cruises indicate that the North Equatorial Undercurrent does not enter the Gulf of Guinea. The South and North Intermediate Countercurrents are variable with longitude and, contrarily to the... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10036/9583.pdf |
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