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| Registros recuperados: 11 | |
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| Nubi, O. A.; Oyatola, O.o; Bonou, F. |
| In attempt to study the spatial differences in autumnal equatorial upwelling intensity relative to bio-productivity in the eastern equatorial Atlantic, oceanographic in situ data along regions 10°W, 0°E, 2.5°E and 6°E, collected in the Gulf of Guinea during autumn cruise carried out in September 2007 were analyzed. The surface mean values for temperature along 10°W, 0°E, 2.5°E and 6°E are 25.02, 26.15, 26.88 and 25.60°C, respectively. There was eastward weakening of the equatorial undercurrent from 10°W until its complete disappearance at 6°E. The highest concentration of nitrate recorded at the surface at 10°W was attributed to the shoaling pycnocline observed at this region. The surface mean values for nitrate along 10°W, 0°E, 2.5°E and 6°E are 0.37,... |
| Tipo: Text |
Palavras-chave: Vertical mixing; Zonal advection; Equatorial undercurrent; Equatorial upwelling; Gulf of Guinea; Nutrients; Phytoplankton biomass; Surface enrichment.. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00621/73318/72485.pdf |
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| Bouruet-aubertot, Pascale; Cuypers, Yannis; Ferron, Bruno; Dausse, Denis; Menage, Olivier; Atmadipoera, Agus; Jaya, Indra. |
| Microstructure measurements were performed along two sections through the Halmahera Sea and the Ombai Strait and at a station in the deep Banda Sea. Contrasting dissipation rates (𝜖) and vertical eddy diffusivities (K z ) were obtained with depth-averaged ranges of ∼[9×10−10−10−5] W kg− 1 and of ∼[1×10−5−2×10−3] m2 s− 1, respectively. Similarly, turbulence intensity, I=ϵ/(νN2) with ν the kinematic viscosity and N the buoyancy frequency, was found to vary seven orders of magnitude with values up to 107. These large ranges of variations were correlated with the internal tide energy level, which highlights the contrast between regions close and far from internal tide generations. Finescale parameterizations of 𝜖 induced by the breaking of... |
| Tipo: Text |
Palavras-chave: Turbulence; Internal tides; Vertical mixing; Parameterization; Indonesian seas; Microstructure measurements. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55240/56792.pdf |
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| Camara, I.; Kolodziejczyk, Nicolas; Mignot, Juliette; Lazar, Alban; Gaye, Amadou T.. |
| The physical processes controlling the mixed layer salinity (MLS) seasonal budget in the tropical Atlantic Ocean are investigated using a regional configuration of an ocean general circulation model. The analysis reveals that the MLS cycle is generally weak in comparison of individual physical processes entering in the budget because of strong compensation. In evaporative regions, around the surface salinity maxima, the ocean acts to freshen the mixed layer against the action of evaporation. Poleward of the southern SSS maxima, the freshening is ensured by geostrophic advection, the vertical salinity diffusion and, during winter, a dominant contribution of the convective entrainment. On the equatorward flanks of the SSS maxima, Ekman transport mainly... |
| Tipo: Text |
Palavras-chave: Salinity; Seasonal variation; Tropical Atlantic; Vertical mixing. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00624/73563/73200.pdf |
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| Song, Hajoon; Marshall, John; Munro, David R.; Dutkiewicz, Stephanie; Sweeney, Colm; Mcgillicuddy, D. J., Jr.; Hausmann, Ute. |
| We investigate the role of mesoscale eddies in modulating air-sea CO2 flux and associated biogeochemical fields in Drake Passage using in situ observations and an eddy-resolving numerical model. Both observations and model show a negative correlation between temperature and partial pressure of CO2 (pCO(2)) anomalies at the sea surface in austral summer, indicating that warm/cold anticyclonic/cyclonic eddies take up more/less CO2. In austral winter, in contrast, relationships are reversed: warm/cold anticyclonic/cyclonic eddies are characterized by a positive/negative pCO(2) anomaly and more/less CO2 outgassing. It is argued that DIC-driven effects on pCO(2) are greater than temperature effects in austral summer, leading to a negative correlation. In... |
| Tipo: Text |
Palavras-chave: CO2 flux; Mesoscale eddy; Southern Ocean; Vertical mixing; Nutrient fluxes. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00383/49407/49894.pdf |
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| Kozlov, Igor; Romanenkov, Dmitry; Zimin, Alexei; Chapron, Bertrand. |
| The compiled archive of synthetic aperture radar (SAR) images acquired by the Advanced SAR (ASAR) onboard the Envisat satellite over the White Sea during the extended summer periods (May-September) between 2007 and 2011, provides the first detailed analysis of 2-D patterns of internal waves (IWs) in the White Sea. Unambiguously, the primary region of IW activity is the southwestern (SW) Gorlo Strait (GS). LW packets emerging from this area are regularly observed to reach crest lengths up to 200 km, and also to propagate a few hundred kilometers from their origin. Model results confirm that large-scale IWs can be generated every tidal cycle and are able to cross the entire sea. As suggested, the source of these packets is governed by the intense dynamics of... |
| Tipo: Text |
Palavras-chave: SAR imaging; Nonlinear internal waves; The White Sea; Vertical mixing. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00195/30617/29216.pdf |
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| Bennis, Anne-claire; Dumas, Franck; Ardhuin, Fabrice; Blanke, Bruno. |
| Wave set-up is often underestimated by the models (e.g. Raubenheimer et al., 2001). Our paper discusses how the wave set-up may be changed by the inclusion of turbulent mixing in the bottom shear stress. The parameterization developed in Mellor (2002) for phase-averaged oscillatory boundary layer is used for this purpose. Two studies are carried out. The dependence of the parameterization on the vertical discretization and on the magnitude of the near-bottom wave orbital velocity is investigated. The function that distributes the turbulent terms over the vertical is modified, giving a good agreement with the average of the phase-resolved velocities, but an overestimation of the turbulent phase-resolved velocities. Applying that parameterization to simulate... |
| Tipo: Text |
Palavras-chave: Bottom friction; Vertical mixing; Wave set-up; Nearshore processes. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29970/28482.pdf |
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| Hernando, M.P.. |
| The increments in the ultraviolet radiation B (RUVB, 280-320 nm) resultants of the destruction of the ozone layer affect diverse echo-physiologic aspects of the marine phytoplankton. On this study were compared the responses of phytoplankton from an ambient Sub-Antarctic (Channel Beagle, 54º 52´S, 68º 18´W) and another Antarctic (Potter Cove, 62º 14´S, 58º 38´W) to the ultraviolet radiation (RUV). The decrease of the photosynthesis on short term (hours) was observed in both places, however inhibition thresholds were present. In the Beagle Channel, these were for RUVB and ultraviolet radiation A (RUVA, 320-400 nm), respectively, 0,2 and 6,2 Wm-2 for communities with more than 70% diatoms and 0,45 and 14,2 Wm-2, respectively, for communities with more than... |
| Tipo: Theses and Dissertations |
Palavras-chave: Phytoplankton; Photosynthesis; Ultraviolet radiation; Vertical mixing; Taxonomy; Phytoplankton; Taxonomy; Photosynthesis; Ultraviolet radiation; Http://aims.fao.org/aos/agrovoc/c_13344; Http://aims.fao.org/aos/agrovoc/c_7631; Http://aims.fao.org/aos/agrovoc/c_5812; Http://aims.fao.org/aos/agrovoc/c_8046. |
| Ano: 2008 |
URL: http://hdl.handle.net/1834/2868 |
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| Registros recuperados: 11 | |
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