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Registros recuperados: 37
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A new device to follow temporal variations of oxygen demand in deltaic sediments: the LSCE benthic station ArchiMer
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...
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Ano: 2014 URL: http://archimer.ifremer.fr/doc/00230/34126/32597.pdf
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Acoustic backscatter by suspended cohesive sediments: field observations, Seine Estuary, France ArchiMer
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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Analysis of riverine suspended particulate matter fluxes (Gulf of Lion, Mediterranean Sea) using a synergy of ocean color observations with a 3-D hydrodynamic sediment transport model ArchiMer
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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Behaviour of a floc population during a tidal cycle: laboratory experiments and numerical modelling ArchiMer
Verney, Romaric; Lafite, Robert; Brun-cottan, Jean Claude; Le Hir, Pierre.
An approach combining laboratory experiments and numerical modelling was used to investigate the behaviour of a floc population during an idealized tidal cycle. The experiment was conducted on suspended sediments at a concentration of 93 mg l−1 collected in the field. It was based on a jar test device to reproduce tidal-induced turbulence and coupled with a CCD camera system and image post-processing software to monitor floc size distribution. At the same time, a 0D size-class based aggregation/fragmentation model (FLOCMOD) was developed to simulate changes in the floc population over the tidal cycle. Experimental results revealed strong variability of the behaviour of microfloc and macrofloc populations with respect to the varying shear rates observed in...
Tipo: Text Palavras-chave: Flocculation; Tidal cycle; Laboratory experiment; FLOCMOD; OD model; Sensitivity analysis; Optimization.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00027/13846/11020.pdf
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Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System (COAWST r1234) ArchiMer
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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Comprendre, Prédire et Agir sur les efflorescences toxiques. Jusqu'où peut-on aller aujourd'hui dans le cas d'Alexandrium minutum en Penzé ? ArchiMer
Chapelle, Annie; Andrieux, Francoise; Fauchot, Juliette; Guillaud, Jean-francois; Labry, Claire; Sourisseau, Marc; Verney, Romaric.
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Ano: 2007 URL: http://archimer.ifremer.fr/doc/00105/21651/19232.pdf
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Development and validation of a sediment dynamics model within a coastal operational oceanographic system ArchiMer
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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Effects of short flexible seagrass Zostera noltei on flow, erosion and deposition processes determined using flume experiments ArchiMer
Ganthy, Florian; Soissons, Laura; Sauriau, Pierre-guy; Verney, Romaric; Sottolichio, Aldo.
Innovative flume experiments were conducted in a recirculating straight flume. Zostera noltei meadows were sampled in their natural bed sediments in the field at contrasting stages of their seasonal growth. The aims of this study were: (i) to quantify the combined effects of leaf flexibility and development characteristics of Zostera noltei canopies on their interaction with hydrodynamics; and (ii) to quantify the role of Zostera noltei meadows in suspended sediment trapping and bed sediment resuspension related with changes in hydrodynamic forcing caused by the seasonal development of seagrasses. Velocity within the canopy was significantly damped. The attenuation in velocity ranged from 34 to 87% compared with bare sediments and was associated with a...
Tipo: Text Palavras-chave: Arcachon Bay; Flexible vegetation; Flow modification; Flume experiments; France; Sediment resuspension; Sediment trapping; Zostera noltei.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00244/35507/34016.pdf
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter ArchiMer
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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Geostationary Image Simulation on Coastal Waters Using Hydrodynamic Biogeochemical and Sedimentary Coupled Models ArchiMer
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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Hydrodynamic and wave parameters calculated from pressure and velocity measurements ArchiMer
Verney, Romaric.
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Ano: 2008 URL: http://archimer.ifremer.fr/doc/00067/17826/15354.pdf
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Impact of winter storms on sediment erosion in the Rhone River prodelta and fate of sediment in the Gulf of Lions (North Western Mediterranean Sea) ArchiMer
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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In situ high frequency long term measurements of suspended sediment concentration in turbid estuarine system (Seine Estuary, France): Optical turbidity sensors response to suspended sediment characteristics ArchiMer
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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Influence des conditions hydrométéorologiques sur les flux et bilans sédimentaires en estuaire de Seine ArchiMer
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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Intercomparaison LISST100X-CILAS à partir de cellules phytoplanctoniques ArchiMer
Verney, Romaric; Lunven, Michel.
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Ano: 2010 URL: http://archimer.ifremer.fr/doc/00067/17820/15348.pdf
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Investigating Rhône River plume (Gulf of Lions, France) dynamics using metrics analysis from the MERIS 300m Ocean Color archive (2002 − 2012) ArchiMer
Gangloff, Aurelien; Verney, Romaric; Doxaran, David; Ody, Anouck; Estournel, Claude.
In coastal environments, river plumes are major transport mechanisms for particulate matter, nutriments and pollutants. Ocean colour satellite imagery is a valuable tool to explore river turbid plume characteristics, providing observations at high temporal and spatial resolutions of suspended particulate matter (SPM) concentration over a long time period, covering a wide range of hydro-meteorological conditions. We propose here to use the MERIS-FR (300 m) Ocean Colour archive (2002–2012) in order to investigate Rhône River turbid plume patterns generated by the two main forcings acting on the north-eastern part of the Gulf of Lions (France): wind and river freshwater discharge. Results are exposed considering plume metrics (area of extension,...
Tipo: Text Palavras-chave: River plume metrics; Sediment dynamics; MERIS; Ocean color data; Suspended particulate matter; Gulf of Lions.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00391/50258/50885.pdf
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MASSILIA: Modélisation de la baie de MArSeILLe : Influence des apports Anthropiques de la métropole sur l’écosystème marin ArchiMer
Pinazo, Christel; Fraysse, Marion; Doglioli, Andrea; Faure, Vincent Martin; Pairaud, Ivane; Petrenko, Anne; Thouvenin, Benedicte; Tronczynski, Jacek; Verney, Romaric; Yohia, Christophe.
In the framework of sustainable development, the anthropogenic impact of large coastal cities on the marine ecosystem is a key issue. This project aimed to improve our knowledge in marine ecosystem response to the anthropogenic supplies (from rivers, sewage outflows and atmosphere) from large cities. In particular, the goal is to underline how the physical forcing decreases or increases the anthropogenic impact on the coastal ecosystem and the assessment of the chemical contaminant (PCB) inputs (from city to sea) and exports (from mid-sea to open sea).
Tipo: Text Palavras-chave: Apports anthropiques; Baie de Marseille; Méditerranée nord-occidentale; Modélisation 3D; MARS3D; ECO3M; Couplage physique et biogéochimique; Anthropogenic supply; Bay of Marseille; North-Western Mediterranean Sea; 3D modelling; MARS3D; ECO3M; Physical-biogeochemical coupling.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00145/25592/23739.pdf
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MASSILIA Project. Modelling of the Bay of Marseille : Impact of the Anthropogenic Supply on the marine coastal ecosystem ArchiMer
Pinazo, Christel; Doglioli, Andrea; Faure, Vincent; Fraysse, Marion; Ross, Oliver; Pairaud, Ivane; Petrenko, Anne; Thouvenin, Benedicte; Tronczynski, Jacek; Verney, Romaric; Yohia, Christophe.
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Ano: 2015 URL: http://archimer.ifremer.fr/doc/00292/40337/38857.pdf
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METROC : modélisation idéalisée de substances dissoutes et particulaires rejetées en rade de Marseille ArchiMer
Jany, Cassandre; Pairaud, Ivane; Thouvenin, Benedicte; Verney, Romaric.
In the context of the METROC project, academic modelling of dissolved and particulate materials were done with the MARS3D model. Considering the dissolved materials, we calculated evacuation times and residence times. Then, we add minimal dilution and percentile maps to assimilate the modelling and the realistic dissolved metal discharge. Considering the particulate materials, we did balance sheets for material exported, sedimenting or staying in water for three different phases (whole modelling 13 October – 31 December 2008, flood situation and resuspension situation). Maps of Marseille roadstead complete that information and allow visualising the principal deposition area. We will continue this work by modelling reel material such as Lead.
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Ano: 2012 URL: http://archimer.ifremer.fr/doc/00090/20088/17724.pdf
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Modeling flocculation processes : intercomparison of a size class-based model and a distribution-based model ArchiMer
Maerz, Joeran; Verney, Romaric; Wirtz, Kai; Feudel, Ulrike.
Modeling suspended particulate matter (SPM) dynamics is essential to calculate sediment transport budgets and to provide relevant knowledge for the understanding of biogeochemical cycles in coastal waters. Natural flocs are characterized by their size, shape, structure and density that determine their settling velocity and therefore their vertical as well as horizontal transport. During transport, several processes, in particular aggregation and fragmentation, alter these particle properties. In the present study, we compare two different 0D modeling approaches for flocculation processes, a size class-based (SCB) model and a distribution-based (DB) model that follows the first moment of the particle distribution function. The study leads to an improved...
Tipo: Text Palavras-chave: Suspended particulate matter (SPM); Flocculation/aggregation; Size class-based model; Distribution-based model; Tidal dynamics; Model comparison.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00027/13870/11064.pdf
Registros recuperados: 37
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