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| Registros recuperados: 13 | |
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| Morrow, Rosemary; Le Traon, Pierre-yves. |
| The paper provides a review of recent results on mesoscale ocean dynamics derived from satellite altimetry. Since 1992, we have had an unprecedented 18 year high-resolution monitoring of the ocean mesoscale field. Altimetry is often used in mesoscale studies in synergy with other remote sensing techniques and in situ data. This global, high-resolution data set has allowed oceanographers to quantify the previously unknown seasonal and interannual variations in eddy kinetic energy and eddy heat and salt transports, and investigate their causes. Eddy tracking techniques have allowed us to monitor their propagation pathways, to bring to light the meridional divergence of cyclones and anticyclones, and to question the role of Rossby waves versus non-linear... |
| Tipo: Text |
Palavras-chave: Satellite altimetry; Mesoscale eddies; Ocean circulation. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19847/17767.pdf |
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| Halo, Issufo; Penven, Pierrick; Backeberg, Bjoern; Ansorge, Isabelle; Shillington, Frank; Roman, Raymond. |
| In this study, we used more than 17 years of satellite altimetry observations and output from an ocean model to investigate the mesoscale eddy variability and forcing mechanisms to the south of Madagascar. Analysis of energy conversion terms in the model has shown seasonality on eddy formation, both by barotropic and baroclinic instabilities: maximum in winter (JJA) and minimum in summer (DJF). The eddies were mainly formed in the upper ocean (0–300 m) and at intermediate depths (800–2000 m) by barotropic and baroclinic instabilities, respectively. The former dominated in the southeastern margin of Madagascar, and the latter to the southwest, where the South-East Madagascar Current (SEMC) separates from the continental shelf. Seasonality of the eddy... |
| Tipo: Text |
Palavras-chave: Mesoscale eddies; Barotropic; Baroclinic instabilities; Seasonality; Eddy properties; Variability. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00222/33348/31749.pdf |
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| Raj, R. P.; Halo, I.; Chatterjee, S.; Belonenko, T.; Bakhoday‐paskyabi, M.; Bashmachnikov, I.; Fedorov, A.; Xie, J.. |
| The interaction between the mesoscale eddies and the cyclonic gyre circulation of the Lofoten Basin is studied using a suite of satellite altimeters, a regional coupled ocean‐sea‐ice data assimilation system (the TOPAZ reanalysis) and Argo float data. An automated method identified 5,373/5,589 individual anticyclonic/cyclonic eddies in the Lofoten Basin from more than 65,000 altimeter‐based eddy observations, of which 70–85% are found to be nonlinear. The nonlinearity of eddies is estimated from its translational and rotational velocities. The study found clustering of highly intense nonlinear eddies on either side of the Lofoten Basin. Further, we show the distinct cyclonic drift of the anticyclonic and cyclonic eddies, both confined to the western side... |
| Tipo: Text |
Palavras-chave: Mesoscale eddies; Lofoten vortex; Lofoten basin; Gyre circulation; Altimetry; Argo floats. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74707/74651.pdf |
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| Noyon, Margaux; Rasoloarijao, Zo; Huggett, Jenny; Ternon, Jean-francois; Roberts, Michael. |
| Seamounts are recognised as hotspots of biodiversity, attracting large numbers of top predators, but the underlying mechanisms are still unclear. We studied mesozooplankton abundance and size distribution at three shallow seamounts (60m, 240m and 18m deep) in the South West Indian Ocean, along a latitudinal gradient (19°S, 27°S and 33°S). Samples were analysed using a ZooScan, allowing the use of a size-based approach. Differences were observed between seamount areas, but overall zooplankton communities did not seem to be affected by the changes in topography. Only in the lee of La Pérouse seamount was the zooplankton community slightly more concentrated than upstream, suggesting that zooplankton were flushed downstream of the seamount. The southernmost... |
| Tipo: Text |
Palavras-chave: Normalised biovolume size spectrum (NBSS); Mesoscale eddies; Topography; Oligotrophic environment; Pelagic ecology. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72157/70920.pdf |
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| Macgilchrist, Graeme A.; Marshall, David P.; Johnson, Helen L.; Lique, Camille; Thomas, Matthew. |
| Ventilation of the upper ocean plays an important role in climate variability on interannual to decadal timescales by influencing the exchange of heat and carbon dioxide between the atmosphere and ocean. The turbulent nature of ocean circulation, manifest in a vigorous mesoscale eddy field, means that pathways of ventilation, once thought to be quasi-laminar, are in fact highly chaotic. We characterize the chaotic nature of ventilation pathways according to a nondimensional filamentation number, which estimates the reduction in filament width of a ventilated fluid parcel due to mesoscale strain. In the subtropical North Atlantic of an eddy-permitting ocean model, the filamentation number is large everywhere across three upper ocean density... |
| Tipo: Text |
Palavras-chave: Ventilation; North Atlantic; Thermocline; Chaos; Mesoscale eddies; Lagrangian trajectories. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00410/52104/52807.pdf |
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| Menna, Milena; Poulain, Pierre-marie; Ciani, Daniele; Doglioli, Andrea; Notarstefano, Giulio; Gerin, Riccardo; Rio, Marie-hélène; Santoleri, Rosalia; Gauci, Adam; Drago, Aldo. |
| The dynamics of the Sicily Channel and the southern Tyrrhenian Sea are highly influenced by the seasonal variability of the Mediterranean basin-wide circulation, by the interannual variability of the numerous mesoscale structures present in the Channel, and by the decadal variability of the adjacent Ionian Sea. In the present study, all these aspects are investigated using in-situ (Lagrangian drifter trajectories and Argo float profiles) and satellite data (Absolute Dynamic Topography, Sea Level Anomaly, Sea Surface Temperature, wind products) over the period from 1993 to 2018. The availability of long time series of data and high-resolution multi-sensor surface currents allow us to add new details on the circulation features and on their driving... |
| Tipo: Text |
Palavras-chave: Sicily Channel; Spatial and temporal variability; Mesoscale eddies. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00505/61674/65601.pdf |
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| Doddridge, Edward W.; Meneghello, Gianluca; Marshall, John; Scott, Jon; Lique, Camille. |
| The Beaufort Gyre (BG) is a large anticyclonic circulation in the Arctic Ocean. Its strength is directly related to the halocline depth, and therefore also to the storage of freshwater. It has recently been proposed that the equilibrium state of the BG is set by the Ice‐Ocean Governor, a negative feedback between surface currents and ice‐ocean stress, rather than a balance between lateral mesoscale eddy fluxes and surface Ekman pumping. However, mesoscale eddies are present in the Arctic Ocean; it is therefore important to extend the Ice‐Ocean Governor theory to include lateral fluxes due to mesoscale eddies. Here, a non‐linear ordinary differential equation is derived that represents the effects of wind stress, the Ice‐Ocean Governor, and eddy fluxes.... |
| Tipo: Text |
Palavras-chave: Beaufort Gyre; Ice-Ocean Governor; Mesoscale eddies; Arctic; Sea ice. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59844/62994.pdf |
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| Keppler, Lydia; Cravatte, Sophie; Chaigneau, Alexis; Pegliasco, Cori; Gourdeau, Lionel; Singh, Awnesh. |
| In the Southwest Pacific Ocean, waters transit from the subtropical gyre before being redistributed equatorward and poleward. While the mean pathways are known, the contribution to the mixing and transport of the water from mesoscale eddies has not been comprehensively investigated. In this research, satellite altimetry data, combined with an eddy detection and tracking algorithm is used to investigate the distribution and surface characteristics of mesoscale eddies in this region of complex bathymetry (10 degrees S-30 degrees S, 140 degrees E-190 degrees E). Detected eddies are then colocalized with in situ data from Argo floats to determine their vertical structure and the effect of eddies on the water masses. The numerous islands affect the eddy... |
| Tipo: Text |
Palavras-chave: Mesoscale eddies; Southwest Pacific; Argo floats; Satellite altimetry. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00489/60039/63314.pdf |
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| Serpette, A; Le Cann, Bernard; Colas, Francois. |
| Between 1994 and 2001, several experiments (ARCANE, SEFOS, INTERAFOS) were conducted to directly measure the general and mesoscale Lagrangian circulations over the Bay of Biscay abyssal plain and slopes. Two levels (~100 m and ~450 m) were selected to cover the North Atlantic Central Water range. Two types of Lagrangian instruments, drogued surface drifters tracked by satellite (Surdrift) and acoustically tracked subsurface floats (Rafos and Marvor), were used. Overall, more than 36 instrument-years were collected in the Bay of Biscay region (43-49°N, 01-12°W). The weak general circulation in the Bay of Biscay is seen to be highly influenced by the occurrence of several mesoscale coherent features, notably slope currents and eddies, and these affect the... |
| Tipo: Text |
Palavras-chave: Slope ocean exchanges; Mesoscale eddies; Slope current; Lagrangian floats and surface drifters; Bay of Biscay. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-6435.pdf |
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| Le Cann, Bernard; Assenbaum, Michel; Gascard, Jean-claude; Reverdin, Gilles. |
| Lagrangian instruments and altimetry data are used to investigate the upper ( 0 to similar to 500 m) mean and mesoscale circulations in a region of the midlatitude northeast Atlantic (36 degrees - 47 degrees N, 13 degrees - 23 degrees W), a formation and subduction area of Subpolar Mode Water. Lagrangian data were collected between September 2000 and September 2001 with isobaric subsurface floats, totaling 34.0 float years, and surface drifting buoys, totaling 27.9 buoy years. The near-surface ( 0 - 100 m) mean circulation is dominated by two weak ( similar to 5 cm/s) eastward currents which veer southward in the domain. In the 100- to 500-m-deep layer, these eastward mean currents retroflect westward and form two anticyclonic circulation cells, opened to... |
| Tipo: Text |
Palavras-chave: Altimetry; Drifting buoys; Acoustic floats; Lagrangian circulation; Mesoscale eddies; Northeastern Atlantic. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-745.pdf |
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| Jia-xun, Li; Ren, Zhang; Chen-zhao, Liu; Hong-jun, Fan. |
| Aiming at the influence of ocean mesoscale eddy on underwater acoustic propagation, a theoretical computation model of ocean mesoscale eddy was established based on the in-situ hydrographic data in the sea area of ocean mesoscale eddy. An underwater acoustic model-MMPE was used to simulate the acoustic propagation under the influence of different types, different intensities and positions of eddies, and different frequencies and depths of sources. It is found that warm-core eddy can make the convergence zone "move back" and the width of it increases, while cold-core eddy can make the convergence zone "move forward" and the width of it decreases. The bigger the intensity of eddy, the more notable the "forward "or "back "effect. Sound source located depths... |
| Tipo: Journal Contribution |
Palavras-chave: Models; Mesoscale eddies; Transmission loss. |
| Ano: 2012 |
URL: http://hdl.handle.net/1834/5830 |
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| Registros recuperados: 13 | |
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