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Registros recuperados: 13 | |
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Sampaio,Edson E.S.. |
The analysis of electromagnetic fields caused by alternate or transient electric currents flowing along a cable in sea water has several applications. It supports the interpretation of electromagnetic geophysical data and safety procedures against the threat of sea mines. The approach to the problem employs a magnetic vector potential in the frequency domain due to a pulse source electric dipole, and performs Laplace and Hankel transforms and integration along the cable, to describe the variation of the magnetic induction field due to an electric dipole of finite length. The result is applicable to shallow or deep sea water environments, adaptable to any transmitting current waveform and useful for wave-field separation. The prospects relate to a... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dipoles; Electromagnetic energy; Induced fields; Sea. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000300007 |
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Vazquez-rodriguez, Marcos; Touratier, Franck; Lo Monaco, Claire; Waugh, D. W.; Padin, X. A.; Bellerby, R. G. J.; Goyet, Catherine; Metzl, Nicolas; Rios, Aida F.; Perez, Fiz F.. |
Five of the most recent observational methods to estimate anthropogenic CO2 (C-ant) are applied to a high-quality dataset from five representative sections of the Atlantic Ocean extending from the Arctic to the Antarctic. Between latitudes 60 degrees N-40 degrees S all methods give similar spatial distributions and magnitude of C-ant. However, discrepancies are found in some regions, in particular in the Southern Ocean and Nordic Seas. The differences in the Southern Ocean have a significant impact on the anthropogenic carbon inventories. The calculated total inventories of C-ant for the Atlantic referred to 1994 vary from 48 to 67 Pg (10(15) g) of carbon, with an average of 54 +/- 8 Pg C, which is higher than previous estimates. These results, both the... |
Tipo: Text |
Palavras-chave: Deep equatorial atlantic; Northern indian-ocean; Water mass ages; CO2; Sea; Transport; Increase; Tracers; Models. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00202/31313/29724.pdf |
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Gerin, R.; Poulain, P. -m.; Taupier-letage, Isabelle; Millot, C.; Ben Ismail, S.; Sammari, Cherif. |
Within the framework of the EGITTO/EGYPT programs, the spatial structure and the temporal variability of the surface circulation in the eastern basin of the Mediterranean Sea was studied with satellite-tracked drifters. A total of 97 drifters drogued to 15-m nominal depth were released between September 2005 and March 2007, regularly along ship-of-opportunity routes in the Sicily Channel and within specific structures during dedicated campaigns in the Levantine sub-basin. This study complements previous ones in the former and in the Ionian, but it is the first one in the latter. After editing and low-pass filtering, the drifter trajectories were used to estimate pseudo-Eulerian statistics: mean current, variance ellipses, mean and eddy kinetic energies. A... |
Tipo: Text |
Palavras-chave: Lagrangian drifters; General circulation; Undrogued drifters; Sea; Variability; Features; Basin; Model; Dynamics. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00204/31480/29891.pdf |
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Morel, A.; Claustre, H.; Antoine, D.; Gentili, B.. |
The optical properties of Case 1 waters have been empirically related to the chlorophyll concentration, [Chl], historically used as an index of the trophic state and of the abundance of the biological materials. The well-known natural variability around the mean statistical relationships is here examined by comparing the apparent optical properties (spectral downward irradiance attenuation and reflectance) as a function of [Chl] in two Case 1 environments, the Pacific and Mediterranean waters. These oceanic zones apparently represent two extremes of the possible bio-optical variability range around the mean. The systematic deviations, in both directions with respect to the average laws, mainly result from the differing contents in non-algal detrital... |
Tipo: Text |
Palavras-chave: Light absorption; Algal biomass; Ocean color; Chlorophyll; Sea; Phytoplankton; Model; Coefficients; Algorithms. |
Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00209/32012/30549.pdf |
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Cahet, G.; Martin, Y.. |
An experimental eutrophication carried out with several technics on mediterranean sea water (Embiez) in autumn shows : - significant variations in the electro-chemical composition of phytoplanktonic excretion; complex organic substances are excreted during two different periods, especially after the Skeletonema costatum bloom; - close relations between heterotrophy (l4C glucose test) and excretion of organic matter by photosynthetic organisms, glucids are always predominant; - the original heterotrophy from the 14c pyruvate test; which is obviously more selective than the 14c glucose test; - the existence of different periods of active ultraplankton. |
Tipo: Text |
Palavras-chave: Eutrophisation; Méditerranée; Embiez; Eutrophication; Mediterranean; Sea; Embiez. |
Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41670/40879.pdf |
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Govin, Aline; Michel, Elisabeth; Labeyrie, Laurent; Waelbroeck, Claire; Dewilde, Fabien; Jansen, Eystein. |
We investigated deep water changes in the Southern Ocean during the last glacial inception, in relationship to surface hydrology and global climatology, to better understand the mechanisms of the establishment of a glacial ocean circulation. Changes in benthic foraminiferal delta(13)C from three high-resolution cores are compared and indicate decoupled intermediate and deep water changes in the Southern Ocean. From the comparison with records from the North Atlantic, South Atlantic, and the Southern Ocean, we show that the early southern deep water delta(13)C drop observed at the MIS 5.5-5.4 transition occurred before any significant reduction of North Atlantic Deep Water ventilation. We propose that this drop is linked to the northward expansion of poorly... |
Tipo: Text |
Palavras-chave: Isotope substage 5E; Ice core; Interglacial period; Climate variability; Deep ocean; Atlantic; Sea; Circulation; Temperature; Hemisphere. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00208/31952/30375.pdf |
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Le tixerant, Matthieu; Bonnin, Marie; Gourmelon, Françoise; Ragueneau, Olivier; Rouan, Mathias; Ly, Ibrahima; Ould zein, Ahmed; Ndiaye, Fatou; Diedhiou, Mohamed; Ndao, Souleye; Ndiaye, Mamadou Bassirou. |
In the marine environment, positive law generates multiple zones and regulatory limits that overlap in space, justifying a cartographic representation as a relevant approach to promote understanding (synthetic vision), analysis (highlighting legal anomalies, inconsistencies and redundancies), dissemination and communication to different audiences (awareness-raising). The article presents a methodology leading to the mapping of marine and coastal environmental law in West Africa, using a geographic information base to produce static or interactive cartographic representations via a Geographic Data Infrastructure (GDI). It shows the contribution of this type of mapping to a transversal approach in a multi-activity, multi-sectoral and multi-scale context. A... |
Tipo: Text |
Palavras-chave: Afrique de l’ouest; Mer; Littoral; Droit de la mer; Environnement; SIG; Cartographie; West Africa; Sea; Coastal zone; Law of the sea; Environment; GIS; Cartography. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00656/76813/81628.pdf |
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Camps, A; Vall-ilossera, M; Villarino, R; Reul, Nicolas; Chapron, Bertrand; Corbella, I; Duffo, N; Torres, F; Miranda, Jj; Sabia, R; Monerris, A; Rodriguez, R. |
Sea surface salinity can be measured by microwave radiometry at L-band (1400-1427 MHz). This frequency is a compromise between sensitivity to the salinity, small atmospheric perturbation, and reasonable pixel resolution. The description of the ocean emission depends on two main factors: 1) the sea water permittivity, which is a function of salinity, temperature, and frequency, and 2) the sea surface state, which depends on the wind-induced wave spectrum, swell, and rain-induced roughness spectrum, and by the foam coverage and its emissivity. This study presents a simplified two-layer emission model for foam-covered water and the results of a controlled experiment to measure the foam emissivity as a function of salinity, foam thickness, incidence angle, and... |
Tipo: Text |
Palavras-chave: Brightness temperature; Emission; Foam; Microwave radiometry; Salinity; Sea. |
Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00000/10940/9268.pdf |
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Vazquez-rodriguez, M.; Touratier, F.; Lo Monaco, C.; Waugh, D. W.; Padin, X. A.; Bellerby, R. G. J.; Goyet, C.; Metzl, N.; Rios, A.f.; Perez, F.f.. |
Five of the most recent observational methods to estimate anthropogenic CO2 (Cant) are applied to a high-quality dataset from five representative sections of the Atlantic Ocean extending from the Arctic to the Antarctic. Between latitudes 60° N–40° S all methods give similar spatial distributions and magnitude of Cant. Conversely, large discrepancies are found in the Southern Ocean and Nordic Seas. The differences in the Southern Ocean have a significant impact on the anthropogenic carbon inventories. The calculated total inventories of Cant for the Atlantic referred to 1994 range from 48 to 67 Pg (1015 g) of carbon, with an average of 54±8 Pg C, which is higher than previous estimates. These results, both the detailed Cant distributions and extrapolated... |
Tipo: Text |
Palavras-chave: Deep equatorial atlantic; Northern indian-ocean; Water mass ages; CO2; Sea; Transport; Increase; Tracers; Models. |
Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00293/40430/38984.pdf |
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Vincent Hubert, Francoise; Wacrenier, Candice; Morga, Benjamin; Lozach, Solen; Quenot, Emmanuelle; Mege, Mickael; Lecadet, Cyrielle; Gourmelon, Michele; Hervio-heath, Dominique; Le Guyader, Soizick. |
The detection of viruses and bacteria which can pose a threat either to shellfish health or shellfish consumers remains difficult. The current detection methods rely on point sampling of water, a method that gives a snapshot of the microorganisms present at the time of sampling. In order to obtain better representativeness of the presence of these microorganisms over time, we have developed passive sampling using the adsorption capacities of polymer membranes. Our objectives here were to assess the feasibility of this methodology for field detection. Different types of membrane were deployed in coastal waters over 2 years and the microorganisms tested using qPCR were: human norovirus (NoV) genogroups (G)I and II, sapovirus, Vibrio spp. and the species... |
Tipo: Text |
Palavras-chave: Norovirus; Ostreid herpes virus 1 μ Var; Vibrio spp; Microbial source tracking; Sea; Passive sampler; Oyster (Crassostrea gigas). |
Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79375/81893.pdf |
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Albaret, J.J.; Ecoutin, J.-M.. |
La réouverture artificielle de la passe de Grand-Bassam, pratiquée en septembre 1987 dans le but de limiter la prolifération des végétaux aquatiques, a modifié l'environnement et la structure des peuplements ichtyologiques de la partie orientale de la lagune Ebrié (Côte d'Ivoire). Les résultats de deux séries d'observations réalisées en mai 1988 montrent une élévation notable de la salinité et une augmentation de la composante marine au sein des peuplements de poissons par rapport à la situation antérieure (années de référence: 1980 et 1981). |
Tipo: Journal Contribution |
Palavras-chave: Lagoons; Communication; Sea; Environmental impact. |
Ano: 1991 |
URL: http://hdl.handle.net/1834/5371 |
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Registros recuperados: 13 | |
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