Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 35
Primeira ... 12 ... Última
Imagem não selecionada

Imprime registro no formato completo
A Lagrangian analysis of the Indian-Atlantic interocean exchange in a regional model - art. no. L14611 ArchiMer
Doglioli, Andrea; Veneziani, M; Blanke, Bruno; Speich, Sabrina; Griffa, A.
We present a new numerical Lagrangian technique based on the coupling of transport computation with spin analysis of trajectories. This method was applied to results from a high-resolution numerical model of the oceanic region around South Africa. We estimated an Indian-Atlantic leakage of about 14 Sv. In the western Cape Basin, approximately 30% of this transport is due to trapping eddies with a ratio between cyclones and anticyclones transport of 1.3. These findings are briefly discussed with respect to recent observations of the highly nonlinear regime found in this area of the Cape Basin.
Tipo: Text Palavras-chave: Anticyclones transport; Cyclones transport; The Indian Atlantic interocean exchange; South Africa; Numerical model.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-1847.pdf
Imagem não selecionada

Imprime registro no formato completo
A model of the general circulation in the Persian Gulf and in the Strait of Hormuz: Intraseasonal to interannual variability ArchiMer
Pous, Stephane; Lazure, Pascal; Carton, Xavier.
Previous studies modeling the circulation and thermohaline structure in the Persian Gulf have suggested that interannual variability and vertical mixing processes could explain the model biases when compared to the few observations available. Here, a realistic, interannual, high-resolution model of the Persian Gulf is presented, validated against observations and then used to describe the intraseasonal to interannual variability in the circulation, water mass formation and exchange through the Strait of Hormuz. Sensitivity experiments to model settings, in particular vertical mixing parameterizations, have been performed in order to have the best comparison with all available observations. Main circulation and water mass characteristics correspond well to...
Tipo: Text Palavras-chave: Persian Gulf; Strait of Hormuz; Numerical model; Hydrology; Currents; Interannual variability.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00244/35563/35324.pdf
Imagem não selecionada

Imprime registro no formato completo
A numerical modelling study of upwelling filaments off the NW African coast ArchiMer
Stevens, I; Johnson, J.
A fine resolution (1/12degrees x 1/12degrees) primitive equation limited area model is constructed for the region off NW Africa in the eastern North Atlantic to examine the generation of cool upwelling filaments. A seasonal shift in the trade wind pattern leads to coastal upwelling and an equatorward coastal current. The filaments form at four preferred locations along the NW African coast between 25degreesN and 35degreesN, the largest filament being at Cape Ghir. The generation mechanism for the filaments is similar to the one proposed for filaments in the California current system. As a result of baroclinic instability meanders develop on the coastal current and transport cool upwelled water offshore to form the filaments. During the relaxation phase of...
Tipo: Text Palavras-chave: Modèle numérique; Upwelling; Meso-échelle; Afrique Nord-Ouest; Cape Ghir; Numerical model; Coastal upwelling; Mesoscale features; NW Africa; Cape Ghir.
Ano: 2003 URL: http://archimer.ifremer.fr/doc/00321/43247/42978.pdf
Imagem não selecionada

Imprime registro no formato completo
A numerical study of the generation and propagation of internal solitary waves in the Luzon Strait ArchiMer
Cai, Sq; Long, Xm; Gan, Zj.
A new composite model, which consists of a generation model of the internal tides and a regularized long wave propagation model, is presented to study the generation and evolution of internal solitary waves in the sill strait. Internal bores in the sill strait are first simulated by the generation model. and then the internal tidal field outside of the sill region is given as input for the propagation model. Numerical experiments are carried out to Study the imposing tide, depth profile. channel width and shoaling effect, etc., on the generation and evolution of internal solitary waves. It is shown that only when the amplitude of internal tide at the forcing boundary of the propagation model is large enough that a train of internal solitary waves would be...
Tipo: Text Palavras-chave: Marée interne; Modèle numérique de soliton; Mer de Chine; Internal wave; Soliton; Numerical model; South China Sea.
Ano: 2002 URL: http://archimer.ifremer.fr/doc/00322/43319/42935.pdf
Imagem não selecionada

Imprime registro no formato completo
Agulhas eddy fluxes in a 1/6 degrees Atlantic model ArchiMer
Treguier, Anne-marie; Boebel, O; Barnier, B; Madec, G.
A 1/6degrees resolution primitive equation model of the Atlantic circulation is analyzed in the Agulhas region. The model has a realistic level of eddy kinetic energy, and produces anticyclonic Agulhas rings as well as cyclonic structures. In the model as well as in the data, ring trajectories undergo a transition between a turbulent character in the Cape Basin and a steady propagation in the rest of the South Atlantic. The topography of the Walvis Ridge does not seem to play a part in generating this contrast in the model. The model shows that cyclones are primarily generated from the negative shear vorticity side of the Agulhas Current as it leaves the coast, and they are most of the time paired with anticyclones in dipolar or tripolar structures....
Tipo: Text Palavras-chave: South Africa; South Atlantic Ocean; Numerical model; Ocean currents; Oceanic eddies; Eddy flux.
Ano: 2003 URL: http://archimer.ifremer.fr/doc/2003/publication-453.pdf
Imagem não selecionada

Imprime registro no formato completo
Can a Warmer Climate Save Northern Agriculture? AgEcon
Gaasland, Ivar.
Agriculture at high latitudes is expected to be a main beneficiary of a man-made climate change. A numerical model, using Norway as a case, is employed to analyze the impacts of a warmer climate on northern agriculture. The computations indicate that the current degree of self-sufficiency can be achieved with less budget support and higher economic welfare. However, it may be argued that environmental goods, such as landscape and biodiversity preservation, and rural settlement, are more important than self-sufficiency for northern agriculture. It is demonstrated that, in that case, welfare gains are substantially lower, and can even be negative.
Tipo: Conference Paper or Presentation Palavras-chave: Climate change; Northern agriculture; Environmental goods; Numerical model; Environmental Economics and Policy; Resource /Energy Economics and Policy; L52; Q18; Q24.
Ano: 2005 URL: http://purl.umn.edu/24551
Imagem não selecionada

Imprime registro no formato completo
Caractérisation expérimentale et numérique du comportement hydrodynamique d’une hydrolienne à membrane ondulante ArchiMer
Trasch, Martin.
The thesis presented in this document deals with the caracterisation of the behaviour of an undulating membrane tidal energy converter. This kind of device uses the flutter instabilities occurring between a semi-rigid pre-strained membrane and a fluid flow in order to convert the sea currents energy. Above a certain critical flow speed, the structure ondulates, thus activating the linear converters fixed on it. In order to study this system, an experimental model is developped and tested in a flume tank. The power conversion system is simulated by hydraulic dampers. The membrane’s dynamics is analysed in many configurations through trajectory and force measurements, and leads to a parametric study. More realistic flow conditions are also studied, such as...
Tipo: Text Palavras-chave: Énergies marines renouvelables; Hydrolienne; Interaction fluidestructure; Instabilité de flottement; Essais expérimentaux; Particle Image Velocimetry; Modélisation numérique; Méthode vortex; Éléments finis; Corotationnel; Houle; Effet d’échelle; Marine renewable energy; Tidal energy converter; Power takeoff; Fluid-structure interaction; Flutter instability; Experimental trial; Particle Image Velocimetry; Numerical model; Vortex method; Corotational finite elements; Surface wave; Scale effect.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00490/60185/63527.pdf
Imagem não selecionada

Imprime registro no formato completo
Etude des échanges entre l’Océan Arctique et l’Atlantique Nord : Origine, Variabilité et Impact sur les mers Nordiques ArchiMer
Lique, Camille.
While perhaps the most obvious, ice retreat is just one aspect of a changing Arctic system. The Arctic Ocean is also undergoing unprecedented modifications, that mostly affect its heat and freshwater budgets. As the signal of Arctic change is expected to have its major climatic impact by reaching south the subarctic seas, on either side of Greenland, to modulate the Atlantic thermohaline circulation, the objective of this thesis is to investigate the variability of the exports of volume, heat, freshwater and sea-ice from the Arctic Ocean to the North Atlantic. First, a realistic simulation from 1958 to 2002 run with a global ocean/sea-ice model is used to investigate some aspects of the variability of the Arctic freshwater budget, trying to understand...
Tipo: Text Palavras-chave: Océan Arctique; Bilan d'eau douce; Flux d'eau douce; Glace de mer; Modèle numérique - Analyse Lagrangienne - Forçages atmosphériques; Arctic Ocean; Freshwater budget; Freshwater flux; Sea ice; Numerical model; Lagrangian analysis; Atmospheric forcing.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00015/12597/9474.pdf
Imagem não selecionada

Imprime registro no formato completo
Finite element model for the assessment of the mesh resistance to opening of fishing nets ArchiMer
Morvan, Barthelemy; Priour, Daniel; Guede, Zakoua; Bles, G..
The evaluation of the mesh resistance to opening of fishing nets is an important issue in assessing the selectivity of trawls by numerical methods. Sala et al. (2007) proposed a method using a relatively expensive experimental device ensuring the 2D deformation of net sample. De la Prada and Gonzales (2015) proposed a simple uni-axial experimental set-up, which stretches a sample in the transverse direction of the meshes while leaving free its deformation in the normal direction. Both authors (Sala and De la Prada) assumed that the deformation is uniform in the sample. The present study aims at developing a finite element model taking into account the mesh resistance to opening of nets, allowing the simulation of non-uniform deformation. Mechanical...
Tipo: Text Palavras-chave: Netting; Mesh resistance to opening; Bending stiffness; Experiment; Numerical model.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45813/49043.pdf
Imagem não selecionada

Imprime registro no formato completo
How ocean waves rock the Earth: two mechanisms explain microseisms with periods 3 to 300 s ArchiMer
Ardhuin, Fabrice; Gualtieri, Lucia; Stutzmann, Eleonore.
Microseismic activity, recorded everywhere on Earth, is largely due to ocean waves. Recent progress has clearly identified sources of microseisms in the most energetic band, with periods from 3 to 10 s. In contrast, the generation of longer-period microseisms has been strongly debated. Two mechanisms have been proposed to explain seismic wave generation: a primary mechanism, by which ocean waves propagating over bottom slopes generate seismic waves, and a secondary mechanism which relies on the nonlinear interaction of ocean waves. Here we show that the primary mechanism explains the average power, frequency distribution, and most of the variability in signals recorded by vertical seismometers, for seismic periods ranging from 13 to 300 s. The secondary...
Tipo: Text Palavras-chave: Hum; Infragravity waves; Numerical model; Microseisms.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00251/36219/34769.pdf
Imagem não selecionada

Imprime registro no formato completo
Impact du régime du barrage d'Arzal sur la stratification a l'embouchure de la Vilaine : étude par modélisation numérique ArchiMer
Le Hir, Pierre; Duchene, C.; Merel, A; De Nadaillac, G.; Merceron, Michel; Breton, Marguerite.
The rate of flow of the fresh water releases at the Arzal Dam into the Vilaine is likely to influence the haline structure of Vilaine Bay. In order to determine the rate of flow that causes a minimum downstream stratification, a vertical two-dimensional mathematical modelling of the Vilaine's estuary was undertaken. We obtain very similar stratification flows for different fresh water release scenarios, in spite of the rather different desalinisations and currents.
Tipo: Text Palavras-chave: Water release; Stratification; Estuary; Numerical model; Vilaine; Rejet de barrage; Stratification; Estuaire; Modèle numérique; Vilaine.
Ano: 1986 URL: https://archimer.ifremer.fr/doc/1986/rapport-2654.pdf
Imagem não selecionada

Imprime registro no formato completo
Inverse identification of the bending stiffness of a braided polyethylene twine subject to large deformation: application to the identification of the mesh opening rigidity of fishing nets. ArchiMer
Morvan, Barthelemy; Bles, G; Dumergue, Nicolas; Priour, Daniel.
The evaluation of the mesh opening stiffness of fishing nets is an important issue in assessing the selectivity of trawls. It appeared that a larger bending rigidity of twines decreases the mesh opening and could reduce the escapement of fish. Nevertheless, netting structure is complex. A netting is made up of braided twines made of polyethylene or polyamide. These twines are tied with non-symmetrical knots. Thus, these assemblies develop contact-friction interactions. Moreover, the netting can be subject to large deformation. In this study, we investigate the responses of netting samples to different types of solicitations. Samples are loaded and unloaded with creep and relaxation stages, with different boundary conditions. Then, two models have been...
Tipo: Text Palavras-chave: Numerical model; Experiments; Braided twine; Mesh opening rigidity; Large deformation..
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00348/45899/45581.pdf
Imagem não selecionada

Imprime registro no formato completo
Modeling and forecasting the "weather of the ocean" at the mesoscale ArchiMer
Treguier, Anne-marie; Chassignet, Eric P.; Le Boyer, Arnaud; Pinardi, Nadia.
We present a historical perspective on ocean mesoscale variability and turbulence, from the physical basis and the first numerical models to recent simulations and forecasts. In the mesoscale range (typically, spatial scales of 100 km and time scales of a month), nonlinearity, and energy cascades were well understood in the 1970s, but the emergence of coherent vortices took place much later. New challenges have arisen with the exploration of the submesoscale regime, where frontal dynamics play a key role and the range of flow instabilities is wider than in the quasi-geostrophic regime. Special focus is placed on the interaction of mesoscale turbulence with the continental slopes. The contrast between the variability on the western and eastern boundaries of...
Tipo: Text Palavras-chave: Numerical model; Ocean forecast; Ocean mesoscale turbulence.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00410/52106/52939.pdf
Imagem não selecionada

Imprime registro no formato completo
Modelling cyclonic eddies in the Delagoa Bight region ArchiMer
Cossa, O.; Pous, Stephane; Penven, P.; Capet, X; Reason, C. J. C..
The objective of this study is to document and shed light on the circulation around the Delagoa Bight region in the southern Mozambique Channel using a realistic modelling approach. A simulation including mesoscale forcings at the boundaries of our regional configuration succeeds in reproducing the general circulation in the region as well as the existence of a semi-permanent cyclonic eddy, whose existence is attested by in situ measurements in the Bight. Characterised by a persistent local minimum in SSH located around 26 °S—34 °E, this cyclonic eddy termed herein the Delagoa Bight lee eddy occurs about 25% of the time with no clear seasonal preference. Poleward moving cyclones, mostly generated further north, occur another 25% of the time in the Bight...
Tipo: Text Palavras-chave: Delagoa Bight; Cyclonic lee eddy; Coastal countercurrent; Numerical model; Mozambique Channel; Shelf processes.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00318/42941/42449.pdf
Imagem não selecionada

Imprime registro no formato completo
Modelling for anchovy recruitment studies in the Gulf of Lions (Western Mediterranean Sea) ArchiMer
Nicolle, Amandine; Garreau, Pierre; Liorzou, Bernard.
Anchovy (Engraulis encrasicolus) is an important commercial species and one of the most abundant pelagic fish in the Gulf of Lions and the Catalan Sea. The factors influencing its recruitment are crucial to fisheries and ecological research. Among those factors transport of larvae by hydrodynamics (currents) is important because it determines whether the organisms can reach areas favourable to recruitment or are dispersed. Therefore, the first step in anchovy recruitment modelling is to simulate North-western Mediterranean Sea circulation. Several years (2001-2008) of hydrodynamics were simulated with the MARS-3D code. The resulting simulated currents and salinity are used by Lagrangian tool, Ichthyop, to transport anchovy eggs and larvae to the Western...
Tipo: Text Palavras-chave: Diel vertical migration; Lagrangian transport; Gulf of Lions; Numerical model; Mediterranean Sea; Anchovy.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-7394.pdf
Imagem não selecionada

Imprime registro no formato completo
Modelling larval dispersal of the king scallop (Pecten maximus) in the English Channel: examples from the bay of Saint-Brieuc and the bay of Seine ArchiMer
Nicolle, Amandine; Dumas, Franck; Foveau, Aurelie; Foucher, Eric; Thiebaut, Eric.
The king scallop (Pecten maximus) is one of the most important benthic species of the English Channel as it constitutes the first fishery in terms of landings in this area. To support strategies of spatial fishery management, we develop a high-resolution biophysical model to study scallop dispersal in two bays along the French coasts of the English Channel (i.e. the bay of Saint-Brieuc and the bay of Seine) and to quantify the relative roles of local hydrodynamic processes, temperature-dependent planktonic larval duration (PLD) and active swimming behaviour (SB). The two bays are chosen for three reasons: (1) the distribution of the scallop stocks in these areas is well known from annual scallop stock surveys, (2) these two bays harbour important fisheries...
Tipo: Text Palavras-chave: King scallop; English Channel; Numerical model; Lagrangian transport; Planktonic larval duration; Swimming behaviour.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00146/25705/26396.pdf
Imagem não selecionada

Imprime registro no formato completo
Multifunctionality of Agriculture: An Inquiry Into the Complementarity Between Landscape Preservation and Food Security AgEcon
Brunstad, Rolf Jens; Gaasland, Ivar; Vardal, Erling.
Without support, the levels of agricultural public goods will fall short of the demand in high cost countries like Norway, Finland and Iceland. However, as demonstrated in this paper using Norway as a case, the current support and agricultural activity is far out of proportions from a public goods perspective. Model simulations show that at most 40% of the current support level can be defended by the public good argument. Furthermore, the present support, stimulating high production levels, is badly targeted at the public goods in question. Since agricultural land is a major component of both food security and landscape preservation, thus giving rise to a high degree of cost complementarities between the two public goods, it would be more efficient to...
Tipo: Conference Paper or Presentation Palavras-chave: Food security; Landscape preservation; Public goods; Agricultural policy; Numerical model; Food Security and Poverty; Land Economics/Use.
Ano: 2005 URL: http://purl.umn.edu/24470
Imagem não selecionada

Imprime registro no formato completo
Numerical model validation for mooring systems: Method and application for wave energy converters ArchiMer
Harnois, V.; Weller, Sam D.; Johanning, L.; Thies, P. R.; Le Boulluec, Marc; Le Roux, Dominique; Soule, Veronique; Ohana, Jeremy.
The design of wave energy mooring systems is challenging: overdesign incurs a significant cost penalty, underdesign may lead to a premature failure and incorrect design could reduce the power production. Consequently, compliant mooring systems are being developed for wave energy applications. This paper presents tank test results for a scale model of the buoy and mooring used at the SouthWest Mooring Test Facility (SWMTF), an offshore facility developed to conduct long-term sea trials for wave energy device moorings. A compliant three leg catenary mooring system using Nylon ropes in the water column is investigated. Preliminary static, quasi-static, decay, regular and irregular wave tests were conducted on the 1:5 scale model, using the Ifremer basin in...
Tipo: Text Palavras-chave: Wave energy converter; Tank tests; Numerical model; Highly dynamic mooring system; Fibre rope.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00233/34375/35785.pdf
Imagem não selecionada

Imprime registro no formato completo
Numerical modeling of the effect of variation of boundary conditions on vadose zone hydraulic properties Rev. Bras. Ciênc. Solo
Leão,Tairone Paiva; Gentry,Randall.
An accurate estimation of hydraulic fluxes in the vadose zone is essential for the prediction of water, nutrient and contaminant transport in natural systems. The objective of this study was to simulate the effect of variation of boundary conditions on the estimation of hydraulic properties (i.e. water content, effective unsaturated hydraulic conductivity and hydraulic flux) in a one-dimensional unsaturated flow model domain. Unsaturated one-dimensional vertical water flow was simulated in a pure phase clay loam profile and in clay loam interlayered with silt loam distributed according to the third iteration of the Cantor Bar fractal object Simulations were performed using the numerical model Hydrus 1D. The upper and lower pressure heads were varied around...
Tipo: Info:eu-repo/semantics/report Palavras-chave: Numerical model; Hydrus 1D; Uncertainty; Boundary conditions; Hydraulic conductivity; Soil physics.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000100025
Imagem não selecionada

Imprime registro no formato completo
Numerical modelling of equilibrium and evolving lightweight sediment laboratory beach profiles. ArchiMer
Dubarbier, Benjamin; Castelle, Bruno; Marieu, Vincent; Michallet, Hervé; Grasso, Florent; Ruessink, Gerben.
The recent advances of numerical beach profile models allowed the simulation of on/offshore sandbar migrations on timescales of weeks to months with fair success. These models were systematically applied to natural, persistently evolving, beaches. In this contribution, we apply our model to small-scale laboratory experiments for which coarse and lightweight sediment is used to satisfy the laws of similitude in the flume. Such experiments can result in equilibrium beach profiles and provide detailed information on the respective role of undertow and wave nonlinearities on sediment transport and the resulting cross-shore sandbar migration. Here we first apply the coupled, wave-averaged, cross-shore waves-currents-bathymetric evolution model 1DBeach to an...
Tipo: Text Palavras-chave: Beach profile; Numerical model; Physical modelling; Equilibrium profile; Sandbar migration.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00180/29089/27503.pdf
Registros recuperados: 35
Primeira ... 12 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional