Consulta: subjectFacets:"Oceanic circulation"
Registros recuperados: 8
Data/hora: 15/06/2024 16:59:02

New insight into the formation and evolution of the East Reykjanes Ridge Current and Irminger Current
Provedor de dados: 5
Autores: Petit, Tillys; Mercier, Herle; Thierry, Virginie.
The Reykjanes Ridge strongly influences the circulation of the North Atlantic Subpolar Gyre as it flows to the Irminger Sea from the Iceland Basin. The circulation is composed of two main along‐ridge currents: the southwestward East Reykjanes Ridge Current (ERRC) in the Iceland Basin and the northeastward Irminger Current (IC) in the Irminger Sea. To study their interconnection through the ridge, as well as their connections with the interior of each basin, velocity and hydrological measurements were carried out along and perpendicular to the crest of the Reykjanes Ridge in June–July 2015 as part of the RREX project. This new dataset changes our view of the ERRC and IC as it reveals undocumented along‐stream evolutions of their hydrological properties,...
Tipo: Text
Palavras-chave: North-Atlantic Subpolar Gyre; Bathymetry; Oceanic circulation; Observations.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00591/70347/68407.pdf

Circulation at the western boundary of the South and Equatorial Atlantic: Exchanges with the ocean interior
Provedor de dados: 5
Autores: Wienders, Nicolas; Arhan, Michel; Mercier, Herle.
Data from a hydrographic section carried out in January-March 1994 offshore from the eastern coast of South America from 50S to 10N, are used to quantify the full-depth exchanges of water between the western boundary currents and the ocean interior. In the upper and intermediate layers, the westward transport associated with the southern branch of the South Equatorial Current was 49 Sv at the time of the cruise. The transports of the central and northern branches in the upper 200 m were 17 Sv and 12 Sv, respectively. After subtraction of the parts that recirculate in the subtropical, subequatorial, and equatorial domains, the fraction of the South Equatorial Current that effectively contributes to the warm water export to the North Atlantic is estimated at...
Tipo: Text
Palavras-chave: South equatorial Atlantic; Boundary current; Oceanic circulation.
Ano: 2000
URL: https://archimer.ifremer.fr/doc/2000/publication-803.pdf

The equatorial thermostad and subsurface countercurrents in the light of the dynamics of atmospheric Hadley cells
Provedor de dados: 5
Autores: Marin, Frederic; Hua, Bach-lien; Wacongne, Sophie.
The simple Held and Hou (1980) nearly inviscid model of the axisymmetric atmospheric circulation, rationalizing the existence of Hadley cells, Jet Streams, and tropical homogenization of potential temperature and vorticity, is adapted to the oceanic subthermocline region. The meridional profile of radiative equilibrium temperature, which provides the driving in the atmospheric case, is replaced, in the oceanic case, by the large-scale equatorial doming of the thermocline. The meridional structure of the equatorial thermostad and the existence, at its poleward flanks, of eastward subsurface countercurrents coincident with sharp potential vorticity gradients are thus explained via angular momentum redistribution by secondary ageostrophic over-turning cells...
Tipo: Text
Palavras-chave: Subthermocline region; Thermostad; Oceanic circulation.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-804.pdf

Small-scale connectivity of coralligenous habitats: insights from a modelling approach within a semi-opened Mediterranean bay
Provedor de dados: 5
Autores: Rossi, Vincent; Lo, Madiop; Legrand, Terence; Ser-giacomi, Enrico; De Jode, Aurélien; Thierry De Ville D’avray, Laure; Pairaud, Ivane; Faure, Vincent; Fraysse, Marion; Pinazo, Christel; Chenuil, Anne.
Habitat connectivity is central to several key evolutionary and ecological processes, having implications for the spatial structuring of marine populations. For benthic species that have no or little mobility as adults, connectivity is evaluated by analyzing the dispersal of propagules across the seascape. We investigate fine-scale connectivity of coralligenous habitats in Marseille Bay (located in the north-western Mediterranean) sea using high-resolution cartography and a particle-tracking model ran over a range of parameters derived from the biological traits of potential target species. We present annual and seasonal means of various connectivity diagnostics measuring the retention and exchange of propagules among coralligenous patches. A synthetic...
Tipo: Text
Palavras-chave: Habitat connectivity; Larval dispersal; Coralligenous assemblages; Benthic organisms; Oceanic circulation; Lagrangian modeling; Population genetics; Community composition.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00680/79225/81737.pdf

The influence of bottom currents on the Zambezi Valley morphology (Mozambique Channel, SW Indian Ocean): In situ current observations and hydrodynamic modelling
Provedor de dados: 5
Autores: Miramontes, Elda; Penven, Pierrick; Fierens, Ruth; Droz, Laurence; Toucanne, Samuel; Jorry, Stephan; Jouet, Gwenael; Pastor, Lucie; Silva Jacinto, Ricardo; Gaillot, Arnaud; Giraudeau, Jacques; Raisson, François.
Mixed turbidite-contourite systems can be found in oceans where bottom currents and turbidity currents interact. The Zambezi turbidite system, located in the Mozambique Channel (SW Indian Ocean), is one of the largest sedimentary systems in the world in length and area of the related catchments. The oceanic circulation in the Mozambique Channel is intense and complex, dominated by eddies flowing southwards and deep currents flowing northwards along the Mozambican margin. Current measurements obtained from moorings at 3400–4050 m water depth in the Zambezi and Tsiribihina valleys show periods of intense currents at the seafloor with peaks of 40–50 cm s−1 that last up to one month and are not related to turbidity currents. These strong bottom-current events...
Tipo: Text
Palavras-chave: Contourite; Turbidity current; Mixed system; Oceanic circulation; Mooring; ADCP; ROMS model; Bedform.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00476/58743/61269.pdf

Deep-water dunes on drowned isolated carbonate terraces (Mozambique Channel, south-west Indian Ocean)
Provedor de dados: 5
Autores: Miramontes, Elda; Jorry, Stephan; Jouet, Gwenael; Counts, John; Courgeon, Simon; Roy, Philippe; Guerin, Charline; Hernández-molina, F. Javier.
Subaqueous sand dunes are common bedforms on continental shelves dominated by tidal and geostrophic currents. However, much less is known about sand dunes in deep‐marine settings that are affected by strong bottom currents. In this study, dune fields were identified on drowned isolated carbonate platforms in the Mozambique Channel (south‐west Indian Ocean). The acquired data include multibeam bathymetry, multi‐channel high‐resolution seismic reflection data, sea floor imagery, a sediment sample and current measurements from a moored current meter and hull‐mounted acoustic Doppler current profiler. The dunes are located at water depths ranging from 200 to 600 m on the slope terraces of a modern atoll (Bassas da India Atoll) and within small depressions...
Tipo: Text
Palavras-chave: Bedform; Bottom currents; Contourite; Deep-marine environment; Eddy; Geostrophic current; Oceanic circulation.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00472/58418/60989.pdf

Contourite distribution and bottom currents in the NW Mediterranean Sea: Coupling seafloor geomorphology and hydrodynamic modelling
Provedor de dados: 5
Autores: Miramontes Garcia, Elda; Garreau, Pierre; Caillaud, Matthieu; Jouet, Gwenael; Pellen, Romain; Hernández-molina, F. Javier; Clare, Michael A.; Cattaneo, Antonio.
Contourites are common morphological features along continental margins where currents encounter the seafloor. They can provide long-term archives of palaeoceanography, may be prone to sediment instability, and can have a great potential for hydrocarbon exploration. Despite their importance and increasingly recognised ubiquitous occurrence worldwide, the link between oceanographic processes and contourite features is poorly constrained. In particular, it is unclear under which specific conditions sediments are mobilised, modified and deposited by bottom currents. Here, we aim to determine key bottom current characteristics (velocity and bottom shear stress) affecting contourite deposition, by assuming that recent oceanographic regimes may be extended back...
Tipo: Text
Palavras-chave: Sediment drift; Erosion; Oceanic circulation; Bottom shear stress.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00483/59426/62241.pdf

Mindanao Dome variability over the last 160 kyr: Episodic glacial cooling of the West Pacific Warm Pool
Provedor de dados: 5
Autores: Bolliet, Timothe; Holbourn, Ann; Kuhnt, Wolfgang; Laj, Carlo; Kissel, Catherine; Beaufort, Luc; Kienast, Markus; Andersen, Nils; Garbe-schoenberg, Dieter.
We present sea surface, upper thermocline, and benthic delta O-18 data, as well as temperature and paleoproductivity proxy data, from the International Marine Global Change Study Program (IMAGES) Core MD06-3067 (6 degrees 31' N, 126 degrees 30' E, 1575 m water depth), located in the western equatorial Pacific Ocean within the flow path of the Mindanao Current. Our records reveal considerable glacial-interglacial and suborbital variability in the Mindanao Dome upwelling over the last 160 kyr. Dome activity generally intensified during glacial intervals resulting in cooler thermocline waters, whereas it substantially declined during interglacials, in particular in the early Holocene and early marine oxygen isotope stage (MIS) 5e, when upwelling waters did...
Tipo: Text
Palavras-chave: Mindanao Dome; East Asian monsoon; Oceanic circulation.
Ano: 2011
URL: https://archimer.ifremer.fr/doc/00213/32472/30924.pdf