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| Registros recuperados: 10 | |
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| Vianello, Patrick; Ternon, Jean-francois; Demarcq, Herve; Herbette, Steven; Roberts, Michael J.. |
| This work is part of the MADRidge Project special issue which aims to describe pelagic ecosystems in the vicinity of three prominent shallow seamounts in the South West Indian Ocean: one here named MAD-Ridge (240 m below the surface) plus Walters Shoal (18 m) on the Madagascar Ridge, and La Pérouse (60 m) on the abyssal plain east of Madagascar. The three span latitudes 20°S and 33°S, some 1500 km. The study provides the background oceanography for the once-off, multidisciplinary snapshot cruise studies around the seamounts. As life on seamounts is determined by factors such as summit depth, proximity to the light layers of the ocean, and the ambient circulation, a first description of regional spatial-field climatologies (16–22 years) and monthly... |
| Tipo: Text |
Palavras-chave: South West Indian Ocean; Madagascar Ridge; Seamounts; Walters shoal; Sea surface temperature; Eddy kinetic energy; Mixed layer depth; Chlorophyll-a; Geostrophic currents. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74581/74476.pdf |
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| Dufois, Francois; Hardman-mountford, Nick J.; Greenwood, Jim; Richardson, Anthony J.; Feng, Ming; Herbette, Steven; Matear, Richard. |
| A unique feature of the subtropical South Indian Ocean is the existence of anticyclonic eddies that have higher chlorophyll concentrations than cyclonic eddies. Off Western Australia, this anomalous behavior is related to the seeding of anticyclonic eddies with shelf water enriched in phytoplankton biomass and nutrients. Further off-shore, two mechanisms have been suggested to explain the eddy/chlorophyll relationship: (i) eddies originating from the Australian coast maintain their chlorophyll anomaly while propagating westward; and (ii) eddy-induced Ekman upwelling (downwelling) enhances (dampens) nutrient supply in anticyclonic (cyclonic) eddies. Here we describe the relationship between eddies and surface chlorophyll within the South Indian Ocean, and... |
| Tipo: Text |
Palavras-chave: Eddies; Chlorophyll; Self-organizing map; Convective mixing; Eddy-induced Ekman pumping. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00233/34464/32862.pdf |
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| Herbette, Steven; Hochet, Antoine; Huck, Thierry; Colin De Verdiere, Alain; Collin, Jeremy; Shillington, Frank. |
| When a source-sink dipole forces a fluid on a beta-plane limited by a western boundary, the linear steady solution can be obtained analytically and consists of zonally elongated gyres that extend west of the forcing and close as western boundary currents. The nondimensional parameter Ro(upsilon) = U/(4 beta a(2)) (with U the zonal velocity of the flow and 2a the distance between the source and sink) is used to characterize the nonlinearity of the flow. When Ro(upsilon) reaches 0.1, the numerical shallow-water solution shows that the configuration with the source to the north of the sink becomes unstable, while the reverse configuration remains steady. Indeed, that reverse configuration remains steady for much larger values of the nonlinearity parameter... |
| Tipo: Text |
Palavras-chave: Beta-plane double-gyre; Source-sink rotating tank experiments; Jet instability; Hopf bifurcation. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32182/30652.pdf |
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| Pivan, Xavier; Krug, Marjolaine; Herbette, Steven. |
| This study re-investigates the work of Lutjeharms et al. [2001,2003] who documented the properties of a Natal Pulse using isopycnal Lagrangian floats. We combined Lagrangian analyses and Eulerian maps derived from objective analysis to better describe the evolution of a Natal Pulse along three density surfaces referred to as the surface (satellite-observed), shallow (isopycnal-1026.8 kg.m−3) and deep (isopycnal-1027.2 kg.m−3) layer. Our observations show that this Natal Pulse extended to a depth of 1000m and was associated with cyclonic relative vorticity values of about 6.5 to 8.5x10−5.s−1 in the surface and shallow layer and 4x10−5.s−1 in the deep layer. This Natal Pulse contributed to cross-shelf exchange through the offshore advection of Eastern... |
| Tipo: Text |
Palavras-chave: Agulhas Current; Natal Pulse; Lagrangian floats. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00350/46162/45860.pdf |
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| Le Paih, Nicolas; Hattermann, Tore; Boebel, Olaf; Kanzow, Torsten; Lüpkes, Christof; Rohardt, Gerd; Strass, Volker; Herbette, Steven. |
| The Weddell Sea is of global importance in the formation of dense bottom waters associated with sea‐ice formation and ocean‐ice sheet interaction occurring on the shelf areas. In this context, the Weddell Sea boundary current system (BCS) presents a major conduit for transporting relatively warm water to the Weddell Sea ice shelves and for exporting {some modified form of Wedell Sea deep and bottom waters into the open ocean. This study investigates the downstream evolution of the structure and the seasonality of the BCS along the Weddell Sea continental slope, combining ocean data collected for the past two decades at three study locations. The interannual‐mean geostrophic flow, which follows planetary potential vorticity contours, shifts from being... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Weddell Sea; Antarctic slope current; Surface stress; Flow strength; Teleconnection. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76398/77436.pdf |
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| Fearon, Giles; Herbette, Steven; Veitch, Jennifer; Cambon, Gildas; Lucas, Andrew J.; Lemarié, Florian; Vichi, Marcello. |
| The land‐sea breeze is resonant with the inertial response of the ocean at the critical latitude of 30°N/S. 1D‐vertical numerical experiments were undertaken to study the key drivers of enhanced diapycnal mixing in coastal upwelling systems driven by diurnal‐inertial resonance near the critical latitude. The effect of the land boundary was implicitly included in the model through the `Craig approximation' for first order cross‐shore surface elevation gradient response. The model indicates that for shallow water depths (<~100~m), bottom shear stresses must be accounted for in the formulation of the ‘Craig approximation’, as they serve to enhance the cross‐shore surface elevation gradient response, while reducing shear and mixing at the thermocline. The... |
| Tipo: Text |
Palavras-chave: Inertial oscillations<; /AUTHOR_KEYWORD>; Land-sea breeze<; /AUTHOR_KEYWORD>; Diurnal-inertial resonance<; /AUTHOR_KEYWORD>; Coastal upwelling<; /AUTHOR_KEYWORD>; Diapycnal mixing<; /AUTHOR_KEYWORD>; Phytoplankton blooms<; /AUTHOR_KEYWORD>. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75507/76384.pdf |
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| Bentamy, Abderrahim; Grodsky, Semyon A; Cambon, Gildas; Tandeo, Pierre; Capet, Xavier; Roy, Claude; Herbette, Steven; Grouazel, Antoine. |
| More than twelve satellite scatterometers have operated since 1992 through the present, providing the main source of surface wind vector observations over global oceans. In this study, these scatterometer winds are used in combination with radiometers and synthetic aperture radars (SAR) for the better determination and characterization of high spatial and temporal resolution of regional surface wind parameters, including wind speed and direction, wind stress components, wind stress curl, and divergence. In this paper, a 27-year-long (1992–2018) 6-h satellite wind analysis with a spatial resolution of 0.125° in latitude and longitude is calculated using spatial structure functions derived from high-resolution SAR data. The main objective is to improve... |
| Tipo: Text |
Palavras-chave: Satellite scatterometer; Surface wind; Upwelling systems; Long time series. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79416/81989.pdf |
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| Desbiolles, Fabien; Bentamy, Abderrahim; Blanke, Bruno; Roy, Claude; Mestas-nunez, Alberto M.; Grodsky, Semyon A.; Herbette, Steven; Cambon, Gildas; Maes, Christophe. |
| Surface winds (equivalent neutral wind velocities at 10 m) from scatterometer missions since 1992 have been used to build up a 20-year climate series. Optimal interpolation and kriging methods have been applied to continuously provide surface wind speed and direction estimates over the global ocean on a regular grid in space and time. The use of other data sources such as radiometer data (SSM/I) and atmospheric wind reanalyses (ERA-Interim) has allowed building a blended product available at 1/4° spatial resolution and every 6 hours from 1992 to 2012. Sampling issues throughout the different missions (ERS-1, ERS-2, QuikSCAT, and ASCAT) and their possible impact on the homogeneity of the gridded product are discussed. In addition, we assess carefully the... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00366/47686/47725.pdf |
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| Le Boyer, A.; Cambon, Gildas; Daniault, N.; Herbette, Steven; Le Cann, B.; Marie, Louis; Morin, P.. |
| The Ushant tidal front is the dominant feature of the summer season hydrological structure of the Iroise Sea. It separates tidally mixed coastal waters from thermally stratified open Celtic Sea waters. This article reports on observations made in September 2007 during two short cruises that took place aboard R/V "Cotes de la Manche", and gives a general account of the physical structure of the front along one cross-frontal transect. The data set comprises data from a 4 month ADCP mooring, short CTD/fluorescence/nutrients transects, Lagrangian drifter trajectories, and HF radar surface current measurements. One finding is that the surface and bottom fronts, being affected by different dynamical influences, are not necessarily coincident in the vertical.... |
| Tipo: Text |
Palavras-chave: Nutrients; Drifters; HF radars; Hydrology; Tidal mixing front; Shelf dynamics. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6417.pdf |
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| Registros recuperados: 10 | |
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