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| Registros recuperados: 48 | |
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| Toussaint, Flora; Rabouille, Christophe; Cathalot, Cecile; Bombled, Bruno; Abchiche, Abdel; Aouji, Oualid; Buchholtz, Gilles; Clemencon, Aurelien; Geyskens, Nicolas; Repecaud, Michel; Pairaud, Ivane; Verney, Romaric; Tisnerat-laborde, Nadine. |
| A new benthic station equipped with oxygen microelectrodes and environmental sensors was developed by Laboratoire des Sciences du Climat et de L’Environnement (LSCE) and Division Technique of the Institut National des Sciences de L’Univers (DT-INSU) to perform in situ time series monitoring of sediment oxygen demand, linked to the mineralization of organic matter. The time series typically cover periods of 2-3 months, with a base frequency of 1 set of oxygen profiles per day. The profiling head assessed the lateral heterogeneity of the sediment oxygen demand at the beginning of the time series over a 0.8-m long rectangle to discriminate spatial and temporal variability. A continuous recalibration is performed using a moored oxygen optode anchored to the... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00230/34126/32597.pdf |
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| Sahin, Cihan; Verney, Romaric; Sheremet, Alexandru; Voulgaris, George. |
| Observations of suspended sediment size and concentration, flow and acoustic backscatter intensity collected on the Seine Estuary (France) are used to study the acoustic response in cohesive-sediment dominated environments. Estimates of suspended sediment concentration based on optical backscatter sensors and water samples are used to calibrate the acoustic backscatter intensity. The vertical structure of suspended sediment concentration is then estimated from acoustic backscatter information. To our knowledge, this is the first field application of the recently proposed model of acoustic scattering by flocculating suspensions based on the variation of particle density (floc-scattering model). The estimates of sediment concentration reproduce well the... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00366/47688/47728.pdf |
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| Le Fouest, Vincent; Chami, Malik; Verney, Romaric. |
| The export of riverine suspended particulate matter (SPM) in the coastal ocean has major implications for the biogeochemical cycles. In the Mediterranean Sea (France), the Rhone River inputs of SPM into the Gulf of Lion (GoL) are highly variable in time, which severely impedes the assessment of SPM fluxes. The objectives of this study are (i) to investigate the prediction of the land-to-ocean flux of SPM using the complementarity (i.e., synergy) between a hydrodynamic sediment transport model and satellite observations, and (ii) to analyze the spatial distribution of the SPM export. An original approach that combines the MARS-3D model with satellite ocean color data is proposed. Satellite-derived SPM and light penetration depth are used to initialize... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00266/37728/35736.pdf |
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| Grasso, Florent; Bismuth, Eliott; Verney, Romaric. |
| En se basant sur les travaux des programmes de recherche Seine-Aval 4 & 5, et plus particulièrement le modèle numérique hydro-sédimentaire MARS3D « CurviSeine » (HYMOSED-SA5), le projet ARES (« Analyse de Rejeux hydro-sédimentaires en Estuaire de Seine ») du programme de recherche Seine-Aval 6 avait pour objectifs de produire un référentiel de données validées de la dynamique hydro-sédimentaire de l’estuaire pour deux périodes de 11 ans (1990-2000 et 2005-2015). Le présent document décrit : (i) le modèle ainsi que les paramètres de modélisation (forçages, grille bathymétrique, etc…) utilisés ; (ii) la comparaison des sorties hydrologiques (température, salinité, sédiments en suspension) du modèle avec les données du réseau PHRESQUES (bouée SCENES et... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00664/77610/79628.pdf |
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| Sherwood, Christopher R.; Aretxabaleta, Alfredo L.; Harris, Courtney K.; Rinehimer, J. Paul; Verney, Romaric; Ferre, Benedicte. |
| We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean-Atmosphere-Wave- Sediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in floc characteristics in the seabed; erosion and deposition of cohesive and mixed (combination of cohesive and non-cohesive) sediment; and biodiffusive mixing of bed sediment. These routines supplement existing noncohesive sediment modules, thereby increasing our ability to model fine-grained and mixed-sediment environments. Additionally, we describe changes to... |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00442/55319/56839.pdf |
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| Cayocca, Florence; Verney, Romaric; Petton, Sebastien; Caillaud, Matthieu; Dussauze, Morgan; Dumas, Franck; Le Roux, Jean-francois; Pineau-guillou, Lucia; Le Hir, Pierre. |
| The rising interest in environmental and ecosystem dynamics have lead coastal oceanographers to not only investigate the “traditional” physical parameters describing the ocean state and its dynamics (e.g. temperature, salinity, currents, water levels in coastal areas), but to also account for the dynamics of parameters describing its biogeochemical components. To that end, MARS3D regional and coastal modelling system has been coupled to ecosystem modules (ECO-MARS3D, ECO3M) as well as sediment dynamics modules (MARS3D-SEDIM): sediment, nutrient and primary production contents can be considered as the lower level environment and ecosystem descriptors of the “biogeochemical” ocean. Early investments into physical and biological analysis at the regional scale... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30572/29015.pdf |
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| Jourdin, Frederic; Tessier, Caroline; Le Hir, Pierre; Verney, Romaric; Lunven, Michel; Loyer, Sophie; Lusven, Andre; Filipot, Jean-francois; Lepesqueur, Jeremy. |
| A pair of self-contained acoustic Doppler current profilers (SC-ADCPs) operating with different frequencies were moored on a muddy sea bottom at about 20 m depth in the Bay of Vilaine off the French Atlantic coast. With their acoustic beams oriented upwards, the SC-ADCPs ensonified most of the water column. The results of several months of in situ recorded echo intensity data spanning 2 years (2003 to 2004) from the dual-frequency ADCPs are presented in this paper. The aim was to estimate suspended particle mass concentration and mean size. A concentration index CI is proposed for the estimation of particle concentration. Based on theory the CI-unlike the volume backscatter strength-does not depend on particle size. Compared with in situ optical data, the... |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00213/32427/30896.pdf |
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| Verney, Romaric; Lafite, Robert; Brun-cottan, Jean-claude. |
| Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a "video in lab" device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a... |
| Tipo: Text |
Palavras-chave: Seine estuary (France); Kolmogorov microscale; Diatom bloom; Floc structure; Cohesive sediment; Flocculation. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6631.pdf |
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| Many, G; Durrieu De Madron, Xavier; Verney, Romaric; Bourrin, F; Renosh, Pr; Jourdin, F; Gangloff, A. |
| Regions Of Freshwater Influence (ROFI) are of particular interest in a source-to-sink approach in terms of sediment advection, settling, and deposition in the coastal zone. An experiment was carried out in the ROFI of the Rhône River in February 2016 to describe the properties of suspended particulate matter (SPM) during a flood event. A digital holographic camera (LISST-HOLO, 20–2000 μm) was used to estimate the variability of fine sediment floc properties (size, nature and shape) formed in the Rhône mouth. An automatic image toolbox was developed to classify the different constituents of the SPM (as diatoms, bubbles and flocs) and to describe the diversity of floc shapes existing in the material in suspension. We estimated the fractal dimension (DF3D),... |
| Tipo: Text |
Palavras-chave: Flocculation; Fractal dimension; Settling velocity; ROFI; Rhone. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00478/58952/61540.pdf |
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| Lei, Manchun; Minghelli, Audrey; Fraysse, Marion; Pairaud, Ivane; Verney, Romaric; Pinazo, Christel. |
| This study proposes a method to simulate the images of the future European geostationary sensor dedicated to ocean color sensor: the geostationary ocean color advanced permanent imager (GeoOCAPI), and it demonstrates the sensor capabilities to monitor the water composition throughout the day. The temporal variation of the coastal seascape is obtained from biogeochemical and hydrosedimentary models, the ocean-atmosphere radiance is obtained from the water and atmosphere radiative transfer model. The GeoOCAPI images are simulated with 400-m resolution, 18 spectral bands with associated signal-to-noise ratio (SNR) and with 1-h acquisition frequency, on the Gulf of Lion (Marseille, France) during a pollution event caused by the urban outfall of Cortiou in... |
| Tipo: Text |
Palavras-chave: Geostationary ocean color advanced permanent imager (GeoOCAPI); Geostationary orbit; Image simulation; Ocean color. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00363/47462/50154.pdf |
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| Gentil, Mathieu; Many, Gaël; Durrieu De Madron, Xavier; Cauchy, Pierre; Pairaud, Ivane; Testor, Pierre; Verney, Romaric; Bourrin, François. |
| The recent integration of Acoustic Doppler Current Profilers (ADCPs) onto underwater gliders changes the way current and sediment dynamics in the coastal zone can be monitored. Their endurance and ability to measure in all weather conditions increases the probability of capturing sporadic meteorological events, such as storms and floods, which are key elements of sediment dynamics. We used a Slocum glider equipped with a CTD (Conductivity, Temperature, Depth), an optical payload, and an RDI 600 kHz phased array ADCP. Two deployments were carried out during two contrasting periods of the year in the Rhone River region of freshwater influence (ROFI). Coastal absolute currents were reconstructed using the shear method and bottom tracking measurements, and... |
| Tipo: Text |
Palavras-chave: Glider; Optics; Acoustics; Satellite; Coastal hydrodynamics; Suspended particulate matter; Particulate fluxes; Gulf of Lions; Mediterranean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00648/76039/76962.pdf |
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| Defontaine, Sophie; Sous, Damien; Morichon, Denis; Verney, Romaric; Monperrus, Mathilde. |
| The present paper reports on a series of field experiments aiming to characterise the functioning of a man-engineered strongly forced salt-wedge estuary: the lower estuary of the Adour river, France. Bottom-moored velocity measurements and surface boat surveys have been performed under low river discharge conditions, for both neap and spring tides, in order to provide a well-documented reference framework to understand the dynamics of water masses, turbulence and suspended particulate matter (SPM) transport in the lower estuary. An additional campaign has been carried out in high river discharge conditions. This first documented in-situ study of the Adour lower estuary demonstrates its variability in terms of hydrological regimes, from salt-wedge to... |
| Tipo: Text |
Palavras-chave: Salt-wedge estuary; Estuarine circulation; Stratification; Turbulence; Suspended particles transport; Adour river. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70049/67987.pdf |
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| Dufois, Francois; Verney, Romaric; Le Hir, Pierre; Dumas, Franck; Charmasson, Sabine. |
| In this study a three-dimensional sediment transport model was developed. The model accounts for both current and wave forcing on the sediment and was implemented over the Gulf of Lions. A two-way nesting technique was used to focus on the Rhone River prodelta which is considered as a sink for riverine sediment. In addition, to understand the resuspension of trapped sediment over the Rhone prodelta, an in situ experiment, called SCOPE, was conducted during the winter 2007/2008. The experiment consisted of measuring hydro-sedimentary parameters using a mooring station comprising a current profiler (ADCP) and an altimeter (acoustic transducer) located in the eastern part of the Rhone prodelta. The three-dimensional transport model was validated using these... |
| Tipo: Text |
Palavras-chave: Sediment transport; Gulf of Lions; Rhone prodelta; 3D modelling; ADCP; ALTUS. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00165/27584/25743.pdf |
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| Druine, Flavie; Verney, Romaric; Deloffre, Julien; Lemoine, Jean-philippe; Chapalain, Marion; Landemaine, Valentin; Lafite, Robert. |
| The aim of this study is to investigate the complex response of optical turbidity sensors (side- and back-scattering sensors) to Suspended Particle Matter (SPM) characteristics and the consequences when investigating SPM dynamics from long-term high frequency monitoring networks. Our investigation is based on the analysis of a unique dataset of monthly 12 h cycle measurements of SPM characteristics such as turbidity, concentration, floc size distribution, floc density and organic matter content in the macrotidal Seine Estuary (France) between February 2015 and June 2016. Results reveal that despite calibration to a Formazin standard, turbidity sensor response to SPM concentrations (in the range of 7–7000 mg L−1) are strongly variable, from the tidal scale... |
| Tipo: Text |
Palavras-chave: Turbidity; Suspended sediment concentration; Optical sensor; Flocs; Long term monitoring. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00431/54227/55550.pdf |
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| Fettweis, M; Toorman, E; Verney, Romaric; Chapalain, Marion; Legrand, S; Lurton, Xavier; Montereale-gavazzi, G; Roche, M; Shen, X; Van Den Eynde, Dries; Van Lancker, Vera. |
| Context To protect the marine environment more effectively, the European Union adopted the Marine Strategy Framework Directive (MSFD) in 2008, aiming to achieve the Good Environmental Status (GES) of the EU's marine waters by 2020 and to protect the resource base upon which marine-related economic and social activities depend. A major challenge in the implementation of the MSFD is to achieve the necessary scientific knowledge on the marine environment, its processes and the methods to monitor them. The focus of INDI67 is on the evaluation and development of indicators to monitor GES of descriptor 6 and 7. Seafloor integrity (descriptor 6) refers to the structure and functions of the benthic ecosystems. It relates to the comprises physical, chemical and... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74632/74526.pdf |
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| Grasso, Florent; Schulz, Elisabeth; Le Hir, Pierre; Verney, Romaric; Thouvenin, Benedicte. |
| La dynamique sédimentaire à l’embouchure de l’estuaire de Seine est principalement contrôlée par les forçages hydrométéorologiques (débit, vent, vagues, marée) et les fortes pressions anthropiques (endiguement, dragage, clapage). La compréhension et la quantification de la dynamique des flux sédimentaires en suspension (sable/vase) est un enjeu majeur, autant d’un point vu écologique (ex. turbidité, envasement) que financier (ex. gestion des chenaux de navigation). La mise en place de réseaux de mesure in situ permet une meilleure compréhension de la dynamique sédimentaire de l’estuaire, mais leur caractère local rend difficile toute estimation des flux et bilans sédimentaires. Pour répondre à ces questions, cette étude s’appuie sur la modélisation... |
| Tipo: Text |
Palavras-chave: Dynamique hydro-sédimentaire; Sable/vase; Estuaire de Seine; Modélisation numérique; Mesures in situ; Dragage; Flux résiduels et bilans; Année/trimestres. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00348/45928/45621.pdf |
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| Registros recuperados: 48 | |
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