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| Registros recuperados: 21 | |
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| Amore, F. O.; Flores, J. A.; Voelker, A. H. L.; Lebreiro, S. M.; Palumbo, E.; Sierro, F. J.. |
| Changes in paleoclimate and paleoproductivity patterns have been identified by analysing, in conjunction with other available proxy data, the coccolithophore assemblages from core MD03-2699, located in the Portuguese margin in the time interval from the Marine Isotope Stage (MIS) 13/14 boundary to MIS 9 (535 to 300 ka). During the Mid-Brunhes event, the assemblages associated with the eccentricity minima are characterised by higher nannoplankton accumulation rate (NAR) values and by the blooming of the opportunistic genus Gephyrocapsa. Changes in coccolithophore abundance are also related to glacial-interglacial cycles. Higher NAR and numbers of coccoliths/g mainly occurred during the interglacial periods, while these values decreased during the glacial... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Mid-Pleistocene; Coccolithophores; Paleoclimate; Paleoproductivity. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00092/20286/17946.pdf |
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| Farias, Ines; Morales-nin, Beatriz; Lorance, Pascal; Figueiredo, Ivone. |
| The biology, ecology, and dynamics of the deep-sea teleost black scabbardfish in the northeast Atlantic are reviewed. The black scabbardfish is a commercial bathypelagic species found in the NE Atlantic mostly from Iceland to the Canary Islands and Western Sahara, at depths from 800 to 1300 m. The spatial structure of its population is still uncertain, although the existence of one single stock that migrates around the NE Atlantic driven by feeding and reproduction is the most likely hypothesis consistent with available data. This review is based on data from commercial fisheries off the Faroe Islands, Hatton Bank, the west of the British Isles, and Portugal (mainland, Azores, and Madeira) and from Icelandic and Scottish scientific surveys collected... |
| Tipo: Text |
Palavras-chave: Deep-water longline fisheries; Migration; Life cycle; Trichiuridae; Aphanopus carbo; North Atlantic Ocean. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00175/28636/27058.pdf |
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| Barbosa Aguiar, A. C.; Menesguen, Claire; Le Gentil, Sylvie; Schopp, Richard; Carton, Xavier. |
| Nearly all the subsurface eddies detected in seismic imaging of sections in the northeast Atlantic have been assumed to be anticyclones containing Mediterranean Water (MW). Fewer MW cyclones have been observed and studied. In this study, the work of previous numerical studies is extended to investigate some characteristics of layering surrounding MW cyclones, using a primitive equation model with equal diffusivities for salinity and temperature to suppress the effects of double diffusion. It is shown that, after a stable state is reached, both anticyclones and cyclones display similar patterns of layering: stacked thin layers of high acoustic reflectivity located above and below the core of each vortex, which do not match isopycnals. The authors conclude... |
| Tipo: Text |
Palavras-chave: Geographic location/entity; North Atlantic Ocean; Circulation/ Dynamics; Small scale processes; Atm/Ocean Structure/ Phenomena; Eddies; Vortices; Observational techniques and algorithms; Acoustic measurements/effects; Models and modeling; Primitive equations model. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00281/39190/37746.pdf |
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| Dessandier, Pierre-antoine; Borrelli, Chiara; Yao, Haoyi; Sauer, Simone; Hong, Wei-li; Panieri, Giuliana. |
| Paleoceanographic investigations in the Arctic and north Atlantic are crucial to understanding past and current climate change, in particular considering amounts of pressure-temperature sensitive gas stored in marine sediments of the region. Many paleoceanographic studies are based on foraminiferal oxygen and carbon stable isotope compositions (δ18O, δ13C) from either planktonic specimens, benthic specimens or both. However, in seafloor regions promixal to high upward methane fluxes, such as where seafloor gas emission and shallow gas hydrate-bearing sediment occur, foraminiferal δ18O and δ13C display a wide range of values. Our study focuses on foraminiferal stable isotope signatures in shallow sediment at core sites in the Arctic and North Atlantic... |
| Tipo: Text |
Palavras-chave: Foraminiferal stable isotopes; Gas hydrates; Authigenic carbonates Arctic Ocean; North Atlantic Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00610/72215/71338.pdf |
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| Thierry, Virginie; De Boisseson, Eric; Mercier, Herle. |
| Combining hydrographic data from the OVIDE (Observatoire de la Variabilité Interannuelle à Decennale/Observatory of the Interannual to Decadal Variability) section (Greenland-Portugal) with Argo and historical CTD data over the period 19902006, we estimate the variability of the core properties of a variety of Subpolar Mode Water (SPMW) observed on the eastern flank of the Reykjanes Ridge. This SPMW acquires its core properties in the winter mixed layer along the eastern side of the Reykjanes Ridge. We find that the February sea surface temperature along the ridge is a proxy for its core temperature. The sources of this mode water are water masses advected by the mean cyclonic circulation in the Iceland Basin. A density compensated tendency for cooling... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Subpolar mode water; North Atlantic Ocean. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3487.pdf |
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| Racape, V.; Thierry, Virginie; Mercier, Herle; Cabanes, Cecile. |
| To improve our understanding of deep circulation, we deployed five Deep‐Argo floats (0–4000 m) in the Charlie Gibbs Fracture Zone (CGFZ), which channels the flow of Iceland‐Scotland Overflow Water (ISOW), a dense water mass of the North Atlantic Ocean. The floats were programmed to drift at 2750 dbar in the ISOW layer. The floats mainly moved westward in the CGFZ, although some of them followed different routes for few cycles depending on northward intrusions of the North Atlantic Current (NAC) over the CGFZ. One float revealed a direct route for ISOW from CGFZ to the Deep Western Boundary Current at Flemish Cap. In the CGFZ, oxygen data acquired by the floats revealed that the ISOW layer, characterized by salinity higher than 34.94 and density greater... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Deep circulation; Deep-Argo float; Mixing; North Atlantic Current; Iceland-Scotland Overflow Water. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00513/62428/66710.pdf |
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| Macgilchrist, Graeme A.; Johnson, Helen L.; Marshall, David P.; Lique, Camille; Thomas, Matthew; Jackson, Laura C.; Wood, Richard A.. |
| A substantial fraction of the deep ocean is ventilated in the high-latitude North Atlantic. Consequently, the region plays a crucial role in transient climate change through the uptake of carbon dioxide and heat. However, owing to the Lagrangian nature of the process, many aspects of deep Atlantic Ocean ventilation and its representation in climate simulations remain obscure. We investigate the nature of ventilation in the high latitude North Atlantic in an eddy-permitting numerical ocean circulation model using a comprehensive set of Lagrangian trajectory experiments. Backwards-in-time trajectories from a model-defined ‘North Atlantic DeepWater’ (NADW) reveal the locations of subduction from the surface mixed layer at high spatial resolution. The major... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Atmosphere-ocean interaction; Lagrangian circulation/transport; Ocean circulation; Boundary currents; Diapycnal mixing. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00646/75833/76825.pdf |
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| Brachet, Sidonie; Le Traon, Pierre-yves; Le Provost, Christian. |
| The objective of the paper is to analyze the degree of realism of the Parallel Ocean Program ( POP) model of the Los Alamos Laboratory using the combined TOPEX/Poseidon and ERS-1/2 (TPERS) sea level anomaly (SLA) data sets and to present a detailed study of mesoscale characteristics in the North Atlantic. This description spans 8 years of data from 1993 to 2000. At first, we focus on the analysis of the mean eddy kinetic energy ( EKE) and show that the major characteristics of mesoscale variability are realistically simulated despite an overestimation of the EKE model in the Gulf Stream region. We then describe the SLA space and timescales and propagation velocities at a resolution never achieved before. There is a high level of agreement between the model... |
| Tipo: Text |
Palavras-chave: Eddy kinetic energy; North Atlantic Ocean. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00087/19841/17491.pdf |
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| Fan, Xue; Send, Uwe; Testor, Pierre; Karstensen, Johannes; Lherminier, Pascale. |
| Mesoscale anticyclonic eddies in the Irminger Sea are observed using a mooring and a glider. Between 2002 and 2009, the mooring observed 53 anticyclones. Using a kinematic model, objective estimates of eddy length scales and velocity structure are made for 16 eddies. Anticyclones had a mean core diameter of 12 km, and their mean peak observed azimuthal speed was 0.1 m s(-1). They had core salinities and potential temperatures of 34.91-34.98 and 4.488-5.34 degrees C, respectively, making them warm and salty features. These properties represent a typical salinity anomaly of 0.03 and a temperature anomaly of 0.28 degrees C from noneddy values. All eddies had small (<< 1) Rossby numbers. In 2006, the glider observed two anticyclones having diameters of... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Eddies; Mesoscale processes. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00137/24832/22921.pdf |
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| Marchal, Olivier; Waelbroeck, Claire; Colin De Verdiere, Alain. |
| Three sediment records of sea surface temperature (SST) are analyzed that originate from distant locations in the North Atlantic, have centennial-to-multicentennial resolution, are based on the same reconstruction method and chronological assumptions, and span the past 15 000 yr. Using recursive least squares techniques, an estimate of the time-dependent North Atlantic SST field over the last 15 kyr is sought that is consistent with both the SST records and a surface ocean circulation model, given estimates of their respective error (co)variances. Under the authors' assumptions about data and model errors, it is found that the 10 degrees C mixed layer isotherm, which approximately traces the modern Subpolar Front, would have moved by ~15 degrees of... |
| Tipo: Text |
Palavras-chave: Inverse methods; Kalman filters; Climate variability; Circulation/ Dynamics; Geographic location/entity; Oceanic variability; Variability; Mathematical and statistical techniques; Fronts; North Atlantic Ocean. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00318/42922/42423.pdf |
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| Aartsen, J.J. van; Gittenberger, E.; Goud, J.. |
| The species of the Pyramidellidae collected during several expeditions in the south-eastern part of the North Atlantic Ocean are listed, with locality data, depth ranges, and notes on nomenclature, systematics and distribution. The samples classified with the genera Eulimella (partly), Anisocycla, Syrnola, Chrysallida and Odostomella are dealt with in this paper. In total 70 species are reported from the research area, 24 of which are described as new to science. A lectotype of Obeliscus gracillima Smith, 1872 (= Eulimella variabilis de Folin, 1870) and neotypes of Chrysallida multicostata (Jeffreys, 1884) and Jaminia obtusa Brown, 1827, are designated. |
| Tipo: Article / Letter to the editor |
Palavras-chave: Pyramidellidae; New species; North Atlantic Ocean; 42.73. |
| Ano: 2000 |
URL: http://www.repository.naturalis.nl/record/215732 |
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| Registros recuperados: 21 | |
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