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| Registros recuperados: 21 | |
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| BITTENCOURT,ABÍLIO C.S.P.; MARTIN,LOUIS; DOMINGUEZ,JOSÉ M.L.; SILVA,IRACEMA R.; SOUSA,DAIANA L.. |
| By using the mean directions of the wave-fronts approaching the Brazilian northeastern coastal stretch comprised between the localities of Real river (Sergipe State) and Galinhos (Rio Grande do Norte State) - coincident with those of the main winds occurring in the area - and their periods, we have defined a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport, as obtained by numerical modelling from the refraction diagrams, taking into consideration the angle of approach and waves heights along the 10-m isobath, was capable of reproducing the patterns of sediment dispersion provided by geomorphic indicators of the longshore drift. All this coastal region, approximately 900 km in length, is... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Littoral drift; Wave refraction; Numerical modelling; Coastal Quaternary evolution; Northeastern Brazilian coast. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000300012 |
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| Mengual, Baptiste; Le Hir, Pierre; Cayocca, Florence; Garlan, Thierry. |
| This study describes the building of a common erosion law for fine sand and mud, mixed or not, in the case of a typical continental shelf environment, the Bay of Biscay shelf, characterized by slightly energetic conditions and a seabed mainly composed of fine sand and muddy sediments. A 3D realistic hydro-sedimentary model was used to assess the influence of the erosion law setting on sediment dynamics (turbidity, seabed evolution). A pure sand erosion law was applied when the mud fraction in the surficial sediment was lower than a first critical value, and a pure mud erosion law above a second critical value. Both sand and mud erosion laws are formulated similarly, with different parameters (erodibility parameter, critical shear stress and power of the... |
| Tipo: Text |
Palavras-chave: Sand-mud mixture erosion; Numerical modelling; Non-cohesive to cohesive transition. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00394/50588/51280.pdf |
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| Grasso, Florent; Le Hir, Pierre. |
| Estuaries are subject to extensive morphological changes through human activities, such as deepening and narrowing via dredging and channelization. The estuary sediment load, characterised by the estuarine turbidity maximum (ETM), can severely increase in response to channel deepening, shifting the estuary from a natural to hyperturbid state. The main processes driving the estuarine circulation, hydrology and sediment dynamics are relatively well known. However, their relative influence on suspended sediment concentration (SSC), as well as their role in the transition toward hyperturbid estuaries, is still a subject of debate. Therefore, this study aims at investigating the relative contribution of key estuarine drivers (gravitational circulation and tidal... |
| Tipo: Text |
Palavras-chave: Estuary deepening and narrowing; Sediment dynamics; Turbidity maximum; Tidal asymmetry; Stratification; Numerical modelling; Morphological changes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00479/59046/65965.pdf |
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| Gualtieri, L; Stutzmann, E; Juretzek, C; Hadziioannou, C; Ardhuin, Fabrice. |
| Primary microseism is the less studied seismic background vibration of the Earth. Evidence points to sources caused by ocean gravity waves coupling with the seafloor topography. As a result, these sources should be in water depth smaller than the wavelength of ocean waves. Using a state-of-the-art ocean wave model, we carry out the first global-scale seismic modeling of the vertical-component power spectral density of primary microseisms. Our modeling allows us to infer that the observed weak seasonality of primary microseisms in the southern hemisphere corresponds to a weak local seasonality of the sources. Moreover, a systematic analysis of the source regions that mostly contribute to each station reveals that stations on both the East and West sides of... |
| Tipo: Text |
Palavras-chave: Numerical modelling; Computational seismology; Seismic noise; Theoretical Seismology. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59842/62990.pdf |
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| Grasso, Florent; Le Hir, Pierre; Bassoullet, Philippe. |
| Sediment transport modelling in estuarine environments, characterised by cohesive and non-cohesive sediment mixtures, has to consider a time variation of erodibility due to consolidation. Generally, validated by settling column experiments, mud consolidation is now fairly well simulated; however, numerical models still have difficulty to simulate accurately the sedimentation and consolidation of mixed sediments for a wide range of initial conditions. This is partly due to the difficulty to formulate the contribution of sand in the hindered settling regime when segregation does not clearly occur. Based on extensive settling experiments with mud-sand mixtures, the objective of this study was to improve the numerical modelling of mixed-sediment consolidation... |
| Tipo: Text |
Palavras-chave: Mud-sand mixtures; Hindered settling; Consolidation; Experiments; Numerical modelling; Segregation. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36539/35168.pdf |
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| Bousquet, Olivier; Barruol, Guilhem; Cordier, Emmanuel; Barthe, Christelle; Bielli, Soline; Calmer, Radiance; Rindraharisaona, Elisa; Roberts, Gregory; Tulet, Pierre; Amelie, Vincent; Fleischer-dogley, Frauke; Mavume, Alberto; Zucule, Jonas; Zakariasy, Lova; Razafindradina, Bruno; Bonnardot, François; Singh, Manvendra; Lees, Edouard; Durand, Jonathan; Mekies, Dominique; Claeys, Marine; Pianezze, Joris; Thompson, Callum; Tsai, Chia-lun; Husson, Romain; Mouche, Alexis; Ciccione, Stephane; Cattiaux, Julien; Chauvin, Fabrice; Marquestaut, Nicolas. |
| The international research program “ReNovRisk-CYCLONE” (RNR-CYC, 2017–2021) directly involves 20 partners from 5 countries of the south-west Indian-Ocean. It aims at improving the observation and modelling of tropical cyclones in the south-west Indian Ocean, as well as to foster regional cooperation and improve public policies adapted to present and future tropical cyclones risk in this cyclonic basin. This paper describes the structure and main objectives of this ambitious research project, with emphasis on its observing components, which allowed integrating numbers of innovative atmospheric and oceanic observations (sea-turtle borne and seismic data, unmanned airborne system, ocean gliders), as well as combining standard and original methods... |
| Tipo: Text |
Palavras-chave: Tropical cyclone; South-west Indian Ocean; Gliders; Unmanned airborne system; Biologging; Sea turtles; Global satellite navigation system; ReNovRisk; Numerical modelling; Climate modelling; Austral and cyclonic swells; Seismic data. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00691/80281/83366.pdf |
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| Carbajal, N; Backhaus, Jo. |
| With the application of a two-dimensional nonlinear hydrodynamical-numerical semi-implicit model, the principal tides M(2), S(2), K(2), N(2), K(1), P(1) and O(1) were studied. Energy budgets of the semi-diurnal M(2) and S(2) were calculated separately. The linear sum of these budgets was compared with the tidal energy budget obtained when these two tidal constituents interact. Since a quadratic form for the bottom friction was used, remarkable differences were found. The results show that in the area of the Colorado River delta, the dissipation of tidal energy is very strong. Intense tidal currents were observed in the same region and over the Salsipuedes Sill. Energy budgets calculated for forcing waves of different periods, but of the same amplitude,... |
| Tipo: Text |
Palavras-chave: Modèle numérique; Marée; Courant résiduel; Bilan énergétique; Seiche; Numerical modelling; Tide; Residual flow; Energy budget; Seiche. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00325/43666/43204.pdf |
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| Martinez, A; Perez, E; Bruno, M. |
| Analysis of water level and current meter series from different locations on the island shelf of Gran Canaria reveals strong variations in tidal properties. Semidiurnal sea level amplitudes agree with the results obtained from global tidal models for this region only on the northern coast of the island, while they decrease towards the southwest (10 cm difference for the M-2 constituent). Semidiurnal currents present maxima at the southeastern and northwestern extremities of the island (30-40 cm s(-1) for M-2) and minima in the north-northeast and southwest (3-6 cm s(-1) for M-2), showing simultaneous strong changes in the phase. Diurnal levels and currents display smaller variations than the semidiurnal band. The behaviour of semidiurnal constituents is... |
| Tipo: Text |
Palavras-chave: Marée; Courant de marée; Île; Modélisation numérique; Îles Canaries; Tide; Tidal current; Island; Numerical modelling; Canary Islands. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00325/43625/43258.pdf |
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| Guyondet, T.; Comeau, L. A.; Bacher, Cedric; Grant, J.; Rosland, R.; Sonier, R.; Filgueira, R.. |
| A spatially explicit coupled hydrodynamic-biogeochemical model was developed to study a coastal ecosystem under the combined effects of mussel aquaculture, nutrient loading and climate change. The model was applied to St Peter's Bay (SPB), Prince Edward Island, Eastern Canada. Approximately 40 % of the SPB area is dedicated to mussel (Mytilus edulis) longline culture. Results indicate that the two main food sources for mussels, phytoplankton and organic detritus, are most depleted in the central part of the embayment. Results also suggest that the system is near its ultimate capacity, a state where the energy cycle is restricted to nitrogen-phytoplankton-detritus-mussels with few resources left to be transferred to higher trophic levels. Annually, mussel... |
| Tipo: Text |
Palavras-chave: Climate change; Nutrient loading; Mussel culture; Carrying capacity; Coastal ecosystem; Numerical modelling. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00275/38624/37191.pdf |
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| Riboulot, Vincent; Sultan, Nabil; Imbert, P.; Ker, Stephan. |
| A review of recent literature shows that two geomorphologically different types of pockmarks, contribute to gas seepage at the seafloor. Type-1 pockmarks are defined as seafloor craters associated to fluid seepage and are the most classical type referred to as “pockmarks” in the literature. In contrast, Type-2 pockmarks reveal a complex seafloor morphology that may result from the formation/decomposition of gas hydrates in underlying sedimentary layers. Interpretation of very-high-resolution seismic data, sedimentological analyses and geotechnical measurements acquired from the Eastern Niger Submarine Delta reveal that Type-2 pockmarks are associated to the presence at depth of a conical body of massive gas hydrates. Based on acquired data, theoretical... |
| Tipo: Text |
Palavras-chave: Pockmarks; Gas hydrates; VHR seismic data; Piezocone; Numerical modelling; Niger Delta. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00301/41215/40643.pdf |
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| Rattan, Sanjay; Myers, Paul G.; Treguier, Anne-marie; Theetten, Sebastien; Biastoch, Arne; Boening, Claus. |
| Model drift in the Labrador Sea in eddy permitting model simulations is examined using a series of configurations based on the NEMO numerical framework. There are two phases of the drift that we can identify, beginning with an initial rapid 3-year period, associated with the adjustment of the model from its initial conditions followed by an extended model drift/adjustment that continued for at least another decade. The drift controlled the model salinity in the Labrador Sea, over-riding the variability. Thus, during this initial period, similar behavior was observed between the inter-annually forced experiments as with perpetual year forcing. The results also did not depend on whether the configuration was global, or regional North Atlantic Ocean. The... |
| Tipo: Text |
Palavras-chave: Numerical modelling; Labrador Sea; Model salinity drift; Boundary currents; Eddy-permitting models. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12411/9226.pdf |
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| Mengual, Baptiste; Le Hir, Pierre; Cayocca, Florence; Garlan, T.. |
| Based on experiments, a trawling-induced erosion dynamics was included in a 3D realistic and pre-validated hydro-sedimentary model so as to assess its contribution to the overall regional sediment dynamics in the specific case of the Bay of Biscay continental shelf. The effect of trawling was investigated throughout a 5-year period in terms of horizontal/vertical fluxes and changes in seabed mud content, and compared to the natural variability of sediment fluxes at different spatio-temporal scales. Trawling is shown in the model to significantly contribute to sediment re-suspension, and changes in the seabed at the scale of the shelf. The contribution of trawling to re-suspension is >80% during the high fishing season at many locations on the outer... |
| Tipo: Text |
Palavras-chave: Sediment fluxes; Bottom trawling; Numerical modelling; Bay of Biscay; Continental shelf. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00500/61146/64574.pdf |
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| Registros recuperados: 21 | |
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