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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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| Boulart, C; Flament, Pierre; Gentilhomme, V; Deboudt, K; Migon, C; Lizon, F; Schapira, M; Lefebvre, Alain. |
| Wet atmospheric deposition of dissolved N, P and Si species is studied in well-mixed coastal ecosystem to evaluate its potential to stimulate photosynthetic activities in nutrient-depleted conditions. Our results show that, during spring, seawater is greatly depleted in major nutrients: Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP) and Silicic acid (Si), in parallel with an increase of phytoplanktonic biomass. In spring (March-May) and summer (June-September), wet atmospheric deposition is the predominant source (> 60%, relative to riverine contribution) for nitrates and ammonium inputs to this N-limited coastal ecosystem. During winter (October-February), riverine inputs of DIN predominate (> 80%) and are annually the most... |
| Tipo: Text |
Palavras-chave: Strait of Dover; Nutrient cycles; River plumes; Atmospheric deposition; Coastal zone; Primary production. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2007.pdf |
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| Barton, Ed; Basterretxea, G; Flament, Pierre; Mitchelson-jacob, Eg; Jones, B; Aristegui, J; Herrera, F. |
| The mountainous Canary Islands present obstacles to the trade winds and to the Canary Current flowing equatorward past them. In situ observations of hydrographic properties and surface winds south of Gran Canaria, together with advanced very high resolution radiometer and synthetic aperture radar images during 2 weeks in summer 1995 are analyzed, A cyclonic eddy shed from the west of the island drifted southwestward at 5 cm s(-1), while the southeast coast was approached by an upwelling filament originating: off NW Africa. A wind lee region bounded by intense horizontal sheer lines had a weak return islandward wind in its center. The lee formed a triangular, diurnally varying, warm water pool with two sea surface temperature maxima separated by lower... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00000/10502/9400.pdf |
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| Flament, Pierre; Lumpkin, Rick; Tournadre, Jean; Armi, Laurence. |
| Observations of the downstream evolution of an oceanic zonal horizontal shear flow at a Reynolds number of about 10(11), formed as the westward North Equatorial Current passes the island of Hawai'i, reveal finite-amplitude anticyclonic vortices resulting from instability of the shear. The initial orbital period of the vortices is exactly one pendulum day (3.1 days at this latitude), centrifugal instability presumably inhibiting stronger vortices from forming. As they move downstream, they appear to pair and merge into successively larger vortices, in a geometric sequence of longer orbital periods; three subharmonic transitions are suggested with final orbital periods near 6, 12 and 24 days. |
| Tipo: Text |
Palavras-chave: Vortex; Oceanic shear flow. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-644.pdf |
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