Consulta: subjectFacets:"Numerical modeling"
Registros recuperados: 22
Data/hora: 05/06/2024 03:38:16

Detection of microseismic compressional (P) body waves aided by numerical modeling of oceanic noise sources
Provedor de dados: 5
Autores: Obrebski, Mathias; Ardhuin, Fabrice; Stutzmann, Eleonore; Schimmel, Martin.
Among the different types of waves embedded in seismic noise, body waves present appealing properties but are still challenging to extract. Here we first validate recent improvements in numerical modeling of microseismic compressional (P) body waves and then show how this tool allows fast detection and location of their sources. We compute sources at similar to 0.2 Hz within typical P teleseismic distances (30-90 degrees) from the Southern California Seismic Network and analyze the most significant discrete sources. The locations and relative strengths of the computed sources are validated by the good agreement with beam-forming analysis. These 54 noise sources exhibit a highly heterogeneous distribution, and cluster along the usual storm tracks in the...
Tipo: Text
Palavras-chave: Compressionnal body waves; Noise source; Double frequency microseism; Numerical modeling.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00161/27251/25448.pdf

Turbulence Modeling and Wave-Current Interactions
Provedor de dados: 5
Autores: Bennis, Anne-claire; Dumas, Franck; Ardhuin, Fabrice; Blanke, Bruno.
The mechanics of rip currents are complex, involving interactions between waves, currents, water levels and the bathymetry, that present particular challenges for numerical models. Here, the effects of a grid-spacing dependent horizontal mixing on the wave-current interactions are studied. Near the shore, wave rays diverge from channels towards bar crests because of refraction by topography and currents, in a way that depends on the rip current intensity which is itself modulated by the horizontal mixing. At low resolution with the grid-spacing dependent horizontal mixing, the wave motion is the same for both coupling modes because the wave deviation by the currents is weak. In high resolution case, however, classical results are found with the stabilizing...
Tipo: Text
Palavras-chave: Numerical modeling; Rip currents; Turbulence modeling; Wave-current interactions.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00601/71288/69695.pdf

Coupled modeling of thermics and hydrogeology with the Cast3M code: application to the Rainbow hydrothermal field (Mid-Atlantic Ridge, 36A degrees 14'N)
Provedor de dados: 5
Autores: Perez, Florian; Muegler, Claude; Jean-baptiste, Philippe; Charlou, Jean-luc.
We present a new numerical tool developed in the Cast3M software framework to model hydrothermal circulation. Thermodynamic properties of one-phase pure water are calculated from the International Association for the Properties of Water and Steam formulation. This new numerical tool is validated on several test cases of convection in closed-top and open-top boxes. Simulations of hydrothermal circulation in a homogeneous-permeability porous medium also give results in good agreement with already published simulations. This new numerical tool is used to construct a geometric and physical conceptual model of the Rainbow vent site at 36A degrees 14(')N on the Mid-Atlantic Ridge. Several configurations are discussed, showing that high temperatures and high mass...
Tipo: Text
Palavras-chave: Hydrothermal system; Mid-ocean ridge; Numerical modeling; Rainbow vent site; Permeability.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00133/24463/23108.pdf

Mesoscale slope current variability in the Gulf of Lions. Interpretation of in-situ measurements using a three-dimensional model
Provedor de dados: 5
Autores: Andre, Gael; Garreau, Pierre; Fraunie, Philippe.
The ECOLOPHY experiments aimed at investigating physical exchanges between coastal and open sea. They were carried out in June and December 2005 over the shelf-break in the North-eastern part of the Gulf of Lions (Northwestern Mediterranean Sea). This area is considered to be the generation zone for the eddy and meandering structures of the Northern Current (NC). The objective of the present work is to examine mesoscale variability of this coastal slope current in the light of available data. Numerical modeling is used to support the field data analysis. ADCP current measurements over a one-year period show that mesoscale activity is maximal in late winter, correlating with the seasonal variability of the NC and, also, partly with local winds, Measured...
Tipo: Text
Palavras-chave: Numerical modeling; Mesoscale variability; Slope Current; Northern Current; Gulf of Lions; Northwestern Mediterranean Sea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6461.pdf

Modeling mud and sand transfers between a macrotidal estuary and the continental shelf: influence of the sediment-transport parameterization
Provedor de dados: 5
Autores: Diaz, Melanie; Grasso, Florent; Le Hir, Pierre; Sottolichio, Aldo; Caillaud, Matthieu; Thouvenin, Benedicte.
Coastal environments are directly influenced by terrigenous inputs coming from rivers through estuaries. Quantifying the amount of nutrients and contaminants transported by sediments from continental areas to the sea is crucial for marine resources protection. However, the complexity of estuarine dynamics makes it difficult to quantify sediment fluxes from field measurements alone and requires numerical modeling. Thus, using a realistic 3D hydrodynamic and sediment transport model, this study aims at evaluating the influence of model empirical parameters on sediment fluxes and estimating uncertainties on mud and sand transfers at a macrotidal estuary mouth. A sensitivity analysis, considering changes in sediment transport parameters, revealed that the...
Tipo: Text
Palavras-chave: Sensitivity analysis; Sediment fluxes; Numerical modeling; Mud; Sand; Gironde Estuary.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00617/72897/71906.pdf

Response of the Southern Benguela upwelling system to fine-scale modifications of the coastal wind
Provedor de dados: 5
Autores: Desbiolles, Fabien; Blanke, Bruno; Bentamy, Abderrahim; Roy, C.
We analyze the results of a regional model of the Southern Benguela upwelling system forced by wind stress fields derived from QuikSCAT observations. Two different horizontal resolutions are considered for the wind stress: QS25 and QS50, corresponding to native 25 and 50 km grids, respectively. The differences between both products highlight the primary importance of fine-scale momentum fluxes for both the structure and intensity of the wind- and wind curl-driven upwelling. Using QS25, we show that the coastal Ekman transport is reduced, leading to a warmer SST and a reduced oceanic coastal jet. QS25 finer wind stress curl patterns also favor the development of a stronger and shallower poleward undercurrent. The addition of a coastal wind correction to...
Tipo: Text
Palavras-chave: Eastern boundary upwelling system; Momentum flux forcing; Wind profile; Numerical modeling; Scatterometry.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00302/41339/40525.pdf

Effects of waves on coastal water dispersion in a small estuarine bay
Provedor de dados: 5
Autores: Delpey, Matthias; Ardhuin, Fabrice; Otheguy, P.; Jouon, Aymeric.
A three-dimensional wave-current model is used to investigate wave-induced circulations in a small estuarine bay and its impact on freshwater exchanges with the inner shelf, related to stratified river plume dispersion. Modeled salinity fields exhibit a lower salinity surface layer due to river outflows, with typical depth of 1 m inside the bay. The asymmetric wave forcing on the bay circulation, related to the local bathymetry, significantly impacts the river plumes. It is found that the transport initiated in the surf zone by the longshore current can oppose and thus reduce the primary outflow of freshwater through the bay inlets. Using the model to examine a high river runoff event occurring during a high-energy wave episode, waves are found to induce a...
Tipo: Text
Palavras-chave: Nearshore dispersion; Wave-current interactions; River plume; Numerical modeling.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00170/28161/26390.pdf

Analysis and visualization of the glass eel behavior (Anguilla anguilla) in the Adour estuary and estimate of its upstream migration speed
Provedor de dados: 5
Autores: Prouzet, Patrick; Odunlami, Marc; Duquesne, Elise; Boussouar, Ahmed.
The studies carried out on the Adour estuary on the migration of glass eels lead to the characterisation of their swimming behavior. Individuals migrate passively with the flood tide current behind the dynamic tide front, and their movements into the water column are linked to the surrounding luminosity and water turbidity. A numerical model was built from observations gathered on glass eel densities during scientific surveys. It uses the outputs of a hydrodynamic model accounting for the variations in the river flow and tide coefficient. It allows the simulation of the displacement of a particle in the longitudinal axis of the estuary. The variation of the vertical movements through the water column takes into account the cloud cover, the moon phases, the...
Tipo: Text
Palavras-chave: Numerical modeling; Fish behavior; Migration; Estuary; Hydrodynamics; Exploitation rate; Glass eel; Anguilla anguilla; Atlantic Ocean.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00000/11171/7531.pdf

Impact of Chronic and Massive Resuspension Mechanisms on the Microphytobenthos Dynamics in a Temperate Intertidal Mudflat
Provedor de dados: 5
Autores: Savelli, Raphael; Bertin, X.; Orvain, Francis; Gernez, P.; Dale, A.; Coulombier, T.; Pineau, P.; Lachaussée, N.; Polsenaere, Pierre; Dupuy, C.; Le fouest, V.
Microphytobenthos (MPB) resuspension is a key mechanism in the transfer of organic matter from productive intertidal mudflats to terrestrial and marine systems. In this study, we infer on the contribution of physical and biological factors involved in the MPB resuspension. We use a physical‐biological coupled model forced by realistic meteorological and hydrodynamical forcings to simulate chronic (without any concomitant sediment resuspension) and massive (driven by bed failure) resuspension over a year. The model simulates mud surface temperature, MPB growth, and grazing by the gastropod Peringia ulvae. The model suggests that MPB resuspension is the highest in spring tides and at the flood beginning due to high current velocity and low water heights that...
Tipo: Text
Palavras-chave: Microphytobenthos; Mudflat; Resuspension; Physical-biological coupling; Numerical modeling.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00599/71114/69416.pdf

Remotely forced biweekly deep oscillations on the continental slope of the Gulf of Guinea
Provedor de dados: 5
Autores: Guiavarc'H, Catherine; Treguier, Anne-marie; Vangriesheim, Annick.
Current meter measurements on the continental slope of the Gulf of Guinea (at 7 degrees 20'S and 1300 m depth) have revealed biweekly oscillations of the currents, bottom intensified and oriented along the bathymetry. We develop a three-dimensional primitive equation model of the Gulf of Guinea to study the oscillations and their forcing mechanism. The high resolution (1/12 degrees) regional model reproduces remarkably well the main characteristics of the deep currents on the continental slope. Experiments with different forcings demonstrate that the biweekly variability at 1300 m depth is remotely forced by equatorial winds. Deep Yanai waves generated by the wind propagate eastward along the equator. Upon reaching the African coast, the energy propagates...
Tipo: Text
Palavras-chave: Gulf of Guinea; Numerical modeling; Coastal trapped waves.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4476.pdf

An eddy-permitting model of the Atlantic circulation: Evaluating open boundary conditions
Provedor de dados: 5
Autores: Treguier, Anne-marie; Barnier, B; De Miranda, A; Molines, J; Grima, N; Imbard, M; Madec, Gerard; Messager, Christophe; Reynaud, Thierry; Michel, Sylvain.
As part of the French CLIPPER project, an eddy permitting model of the Atlantic circulation has been run for 22 years. The domain has open boundaries at Drake passage and at 30 degreesE, from Africa to Antarctica. The simulated mean circulation, as well as the eddy activity, is satisfactory for a 1/3 degrees model resolution, and the meridional heat transport at 30 degreesS is within the range estimated from observations. We use the "mixed" open boundary algorithm of Barnier et al. [1998], which has both a radiation condition and a relaxation to climatology. The climatological boundary forcing strongly constrains the solution in the whole domain. The model heat balance adjusts through the surface (heat flux retroaction term) more than the open boundaries....
Tipo: Text
Palavras-chave: General circulation; Numerical modeling; Oceanography.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-454.pdf

A high-resolution modeling study of the Western Iberian Margin mean and seasonal upper ocean circulation
Provedor de dados: 5
Autores: Nolasco, Rita; Pires, Ana; Cordeiro, Nuno; Le Cann, Bernard; Dubert, Jesus.
The mean seasonal hydrography and circulation of the Western Iberian Margin (WIM) are studied by means of a high-resolution configuration of the Regional Oceanic Modeling System. A comparison of 5-year model averages for January and July with climatological datasets shows a general good agreement in the reproduction of the mean water mass properties and hydrographic distribution. We find that there is a prevailing tendency for slope poleward flow at about 80-100 km offshore at all latitudes from the surface to 1,500 m with strong vertical coupling. This northward flow, which is mainly along slope and amounts up to 8-10 cm s(-1), exhibits several mean flow recirculation regions on its way and evidences of an offshore pathway of poleward flow. Transports at...
Tipo: Text
Palavras-chave: Western Iberian Margin; Numerical modeling; Poleward flow; Upwelling systems.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00163/27442/26232.pdf

Evolution model for the Absheron Mud Volcano: from stratified sediments to fluid mud generation
Provedor de dados: 5
Autores: Blouin, Arthur; Sultan, Nabil; Pierron, Alexandra; Imbert, Patrice; Callot, Jean‐paul.
Submarine mud volcanoes are one of the most spectacular methane expulsion features at the seafloor and they represent a significant geohazard worldwide. In this work we focus on the physical processes controlling the initiation and early evolution of the Absheron mud volcano (AMV). Our analyses were carried out based on basin modeling calibrated thanks to existing seismic interpretation of the AMV, analysis of sediment samples from seabed, and data from two exploration wells. Acquired laboratory geotechnical data allowed us to derive laws considering the impact of gas exsolution on host sediment behaviors. In this study, we identified key geological and physical conditions that led to mud volcano formation: by coupling diffusion processes with...
Tipo: Text
Palavras-chave: Mud volcano; Numerical modeling; Geohazard; Sediment remobilization; Methane.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00658/77002/78258.pdf

Genesis and Architecture of Sequences of Quaternary Coral Reef Terraces: Insights From Numerical Models
Provedor de dados: 5
Autores: Pastier, A-m; Husson, L.; Pedoja, K.; Bezos, A.; Authemayou, C.; Arias-ruiz, C.; Cahyarini, S. Y.
The variety of coral reefs morphologies highlights their sensitivities to several forcings; fossil reefs stack in sequences that are accordingly diverse. In order to understand their genesis and architectures, we devised a numerical approach, accounting for Quaternary sea level oscillations, vertical land motion, initial slope, wave erosion, and reef growth. We first test our model on the subsiding sequence of Hawaii and on the uplifting sequence of Wangi-Wangi (Sulawesi) that bears active barriers. We then construct a parametric study that we analyze based on a comprehensive yet compact description of sequences as barcodes, that depict the vertical distribution of a few geometrical characteristics (number, width, and height of the terraces and barriers)....
Tipo: Text
Palavras-chave: Coral reefs; Reef terraces; Numerical modeling; Geomorphology.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00637/74917/75771.pdf

3D Modeling of the Elastic-Plastic Behavior of Thin Aeronautical Adhesive Films Suited for a Wide Range of Tensile/Compression-Shear Loads
Provedor de dados: 5
Autores: Maurice, Julien; Creac'Hcadec, Romain; Cognard, Jean-yves; Davies, Peter; Meirinhos, Georges; Mahdi, Stephane.
Adhesive bonding is an interesting structural assembling technique for weight saving in modern commercial aircraft, in which the use of composites materials is increasing. In order to meet both optimization and respect of safety conception constraints, the development of accurate numerical strategies is required. Thus, improvement in the experimental characterization and in the design of reliable numerical tools for bonded assemblies is necessary. This paper presents the characterization of the elastic-plastic behaviour of four aeronautical adhesive films, consisting of two epoxy-based resins supported by two types of carrier. The characterization over a wide range of monotonic proportional tensile-shear loads is performed using a modified Arcan test...
Tipo: Text
Palavras-chave: Aeronautical; Mechanical properties of adhesives; Numerical modeling.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00142/25317/26067.pdf

The impact of tides and waves on near-surface suspended sediment concentrations in the English Channel
Provedor de dados: 5
Autores: Guillou, Nicolas; Rivier, Aurelie; Chapalain, Georges; Gohin, Francis.
Numerous ecological problems of continental shelf ecosystems require a refined knowledge of the evolution of suspended sediment concentrations (SSC). The present investigation focuses on the spatial and temporal variabilities of near-surface SSC in coastal waters of the English Channel (western Europe) by exploiting numerical predictions from the Regional Ocean Modeling System ROMS. Extending previous investigations of ROMS performances in the Channel, this analysis refines, with increased spatial and temporal resolutions, the characterization of near-surface SSC patterns revealing areas where concentrations are highly correlated with evolutions of tides and waves. Significant tidal modulations of near-surface concentrations are thus found in the eastern...
Tipo: Text
Palavras-chave: Sediment transport; Numerical modeling; Satellite; ROMS; MERIS; MODIS.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00345/45607/45227.pdf

Modélisation de la dispersion du phosphogypse dans le golfe de Gabès
Provedor de dados: 20
Autores: Bejaoui, B.; Raïs, S.; Koutitonsky, V.
This work concerns the modeling of the phosphogypsum dispersion emitted by the chemical industries in the gulf of Gabès. The CORMIX model based on the dimensional analysis theory is used for this study. An analysis of the sensitivity of the model parameters was initially made; eight simulations were then carried out to determine the space extent of pollution on the level of the gulf. For each condition of tide, we carried out four simulations, two concerns the high tide and two concerns the low tide. Simulations showed that pollution by phosphogypsum is spread out in space over a surface of about 60 km2.
Tipo: Journal Contribution
Palavras-chave: Numerical modeling; Modélisation numérique; Gabès; Dispersion; CORMIX; Phosphogypse; Phosphogypsum; Golfe de Gabès Dispersion Chemical pollutants MED  Tunisia  Gabes Gulf Marine pollution Mathematical models Mathematical models http://aims.fao.org/aos/agrovoc/c_24199.
Ano: 2004
URL: http://hdl.handle.net/1834/1555

Shade-Grown Coffee: Simulation and Policy Analysis for Coastal Oaxaca, Mexico
Provedor de dados: 31
Autores: Batz,   Michael B.; Albers,   Heidi J.; Avalos-Sartorio,   Beatriz; Blackman,   Allen.
Shade-grown coffee provides a livelihood to many farmers, protects biodiversity, and creates environmental services. Many shade-coffee farmers have abandoned production in recent years, however, in response to declines in international coffee prices. This paper builds a farmer decision model under price uncertainty and uses simulation analysis of that model to examine the likely impact of various policies on abandonment of shade-coffee plantations. Using information from coastal Oaxaca, Mexico, this paper examines the role of various constraints in abandonment decisions, reveals the importance of the timing of policies, and characterizes the current situation in the study region.
Tipo: Working or Discussion Paper
Palavras-chave: Coffee farming; Decision analysis; Numerical modeling; Monte Carlo; Price variability; Crop Production/Industries; O13; Q17; Q12; Q23; Q24.
Ano: 2005
URL: http://purl.umn.edu/10511

Modeling water movement in horizontal columns using fractal theory
Provedor de dados: 90
Autores: Leão,Tairone Paiva; Perfect,Edmund.
Fractal mathematics has been used to characterize water and solute transport in porous media and also to characterize and simulate porous media properties. The objective of this study was to evaluate the correlation between the soil infiltration parameters sorptivity (S) and time exponent (n) and the parameters dimension (D) and the Hurst exponent (H). For this purpose, ten horizontal columns with pure (either clay or loam) and heterogeneous porous media (clay and loam distributed in layers in the column) were simulated following the distribution of a deterministic Cantor Bar with fractal dimension H" 0.63. Horizontal water infiltration experiments were then simulated using Hydrus 2D software. The sorptivity (S) and time exponent (n) parameters of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Numerical modeling; Hydrus 2D; Fractal model; Cantor bar; Sorptivity; Soil physics.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000400042

A diachronic view of the net longshore sediment drift during the Late Holocene at the Jequitinhonha River delta, Brazil, using numerical modeling
Provedor de dados: 42
Autores: Bittencourt,Abilio C.S.P.; Dominguez,José M.L.; Tanajura,Clemente A.S.; Silva,Iracema R.; Martin,Louis.
Using numerical modeling, this work estimates sediment dispersion patterns caused by the incidence of waves in five distinct coastline contours of the Jequitinhonha River delta plain during the Late Holocene. For this study, a wave cliate odel based on the construction of ave refraction diagras relative to the current boundary conditions as defined and assumed to be valid for the five coastlines. Numerical modeling from the refraction diagrams was carried out considering the angle of incidence and wave height along the coastline. This work has allowed us to reproduce past and current patterns of net longshore sediment drift defined by a conceptual model developed from the integration of sediment cores, aerial photograph interpretation, C14 datings and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Past and current longshore transport; Wave refraction; Numerical modeling; Holocene; Brazil.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000400008

Wave energy distribution at inlet channel margins as a function of ebb tidal delta morphology: Cananéia Inlet, São Paulo, Brazil
Provedor de dados: 42
Autores: AMBROSIO,BRUNA G.; SOUSA,PAULO H.G.O.; GAGLIARDI,MARCELO H.; SIEGLE,EDUARDO.
Abstract  Wave energy gradients between and along the margins of inlet channels play an important role in defining the inlet margins’ evolutionary processes, mainly those related to spit erosion or accretion, and inlet migration. The aim of this study is to understand the wave power distribution along the margins of a tidal inlet (Cananéia inlet, São Paulo, Brazil), its variation over time, and the influences of the ebb tidal delta morphology on the incoming waves. To evaluate changes in bathymetry and morphology of submersed features, we apply geoprocessing techniques to analyze nautical charts from the Brazilian Navy from 1939, 1971, 1985 and 2004. The numerical model MIKE21 SW was applied to assess wave propagation and nearshore wave power. Hence, wave...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Wave action; Ebb tidal delta; Tidal inlet; Numerical modeling.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652020000100602

Past and current sediment dispersion pattern estimates through numerical modeling of wave climate: an example of the Holocene delta of the Doce River, Espírito Santo, Brazil
Provedor de dados: 42
Autores: Bittencourt,Abílio C.S.P.; Dominguez,José M.L.; Martin,Louis; Silva,Iracema R.; de-Medeiros,Karla O.P.
This paper presents a numerical modeling estimation of the sediment dispersion patterns caused by waves inciding through four distinct coastline contours of the delta plain of the Doce River during the Late Holocene. For this, a wave climate model based on the construction of wave refraction diagrams, as a function of current boundary conditions, was defined and was assumed to be valid for the four coastlines. The numerical modeling was carried out on basis of the refraction diagrams, taking into account the angle of approximation and the wave height along the coastline. The results are shown to be comparable with existing data regarding the directions of net longshore drift of sediments estimated from the integration of sediment cores, interpretation of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Past and current sediment dispersion; Wave refraction; Numerical modeling; Holocene; Brazil.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652007000200014