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| Registros recuperados: 99 | |
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| Davila, Xabier; Rubio, Anna; Artigas, Felipe; Puillat, Ingrid; Manso-narvarte, Ivan; Lazure, Pascal; Caballero, Ainhoa. |
| Mesoscale dynamics play a major role in several ocean processes, not only in the transport of momentum, heat, mass, particles and microorganisms but also in the provisioning of nutrients into the euphotic zone. Mesoscale processes can define niches where specific phytoplankton species flourish. However, this effect is not straightforward in coastal areas, which are submitted to a more complex interplay between different oceanic processes. In this context, the ETOILE campaign surveyed the CapBreton canyon area in the South-East of Bay of Biscay in early August 2017. The main objective of this study was to link the occurrence and distribution of phytoplankton with the mesoscale ocean processes. On top of the remote sensing data available for this area, such... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74733/74723.pdf |
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| Loubersac, Lionel; Lazure, Pascal; Dumas, Franck; Le Roux, Jean-francois; Riou, Philippe; Foucher, Eric; Guillaumont, Brigitte. |
| On the morning of the 31th October 2000, the Italian chemical tanker “Ievoli Sun” sank in the central Channel. Her cargo presented a risk of contamination for the marine environment and nearby coastal environment. From the moment the sinking was announced, Ifremer decided to implement, in almost real time, tools to produce and communicate environmental data. This paper presents the solutions chosen to develop: - a Geographic Information System to prepare maps, - a series of simulations for dispersion at sea of dissolved products - a general information web site structure (see http://www.ifremer.fr/envlit/surveillance/ievoli.htm). This paper will go beyond technical presentations of methods, tools and results obtained to take a critical look at the site’s... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00089/20054/17695.pdf |
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| Lazure, Pascal; Salomon, Jean-claude. |
| The hydrodynamics of coastal zones often reflect the combined action of tides, winds and density differences. Usual two-dimensional numerical models are only partly suited to the study of such mechanisms. A set of two 2-D and 3-D numerical models is described here. Its main characteristics are: an automatic coupling, a specific procedure for shoaling banks, a reduced vertical coordinate system, and a resolution by finite differences. As an example, the complete set is applied to the region of the Loire and Vilaine estuaries in South Brittany (France). Results prove to be coherent with experimental data and enhance our knowledge of the local hydrodynamics. |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00101/21248/18862.pdf |
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| Esnaola, Ganix; Saenz, J.; Zorita, E.; Lazure, Pascal; Ganzedo, U.; Fontan, A.; Ibarra-berastegi, G.; Ezcurra, A.. |
| The coupled variability of the Sea Surface Temperature (SST) and atmosphere-ocean surface heat fluxes over the Bay of Biscay (Eastern North Atlantic) has been analyzed. Daily surface heat fluxes from different meteorological reanalyses are combined with a high resolution reconstructed satellite SST data set by means of Lagged Maximum Covariance Analysis (MCA). Lagged MCA is applied at different spatial scales. Its results are interpreted within the framework of Hasselmann's stochastic climate model. The surface heat-flux feedback on SST is confirmed to be generally negative. No clear relation is found between the first MCA expansion series and the leading Sea Level Pressure (SLP) patterns. However, a clear relation is found between the second expansion... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19937/17605.pdf |
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| Huret, Martin; Dadou, Isabelle; Dumas, Franck; Lazure, Pascal; Garcon, Véronique. |
| A coupled three-dimensional physical-biogeochemical model was developed in order to simulate the ecological functioning of the Rio de la Plata estuary and plume. The biogeochemical model reproduces the nitrogen cycle between five compartments: dissolved inorganic nitrogen, phytoplankton, zooplankton, detritus and dissolved organic nitrogen. The coupling is tested in seasonal climatological configurations and for the particular year 1999. The circulation is forced with Parana and Uruguay rivers discharges, NCEP wind and tide. The biogeochemical model includes loads of inorganic and organic nitrogen from both rivers. The model reproduces the correct tidal amplitudes in the estuary, as well as the most outstanding features of the observed horizontal and... |
| Tipo: Text |
Palavras-chave: Rio de la Plata; SeaWiFS; Primary production; Chlorophyll; River plumes; Biogeochemical modelling; Physical. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-334.pdf |
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| Esnaola, G.; Saenz, J.; Zorita, E.; Fontan, A.; Valencia, V.; Lazure, Pascal. |
| The combination of remotely sensed gappy Sea surface temperature (SST) images with the missing data filling DINEOF (data interpolating empirical orthogonal functions) technique, followed by a principal component analysis of the reconstructed data, has been used to identify the time evolution and the daily scale variability of the wintertime surface signal of the Iberian Poleward Current (IPC), or Navidad, during the 1981-2010 period. An exhaustive comparison with the existing bibliography, and the vertical temperature and salinity profiles related to its extremes over the Bay of Biscay area, show that the obtained time series accurately reflect the IPC-Navidad variability. Once a time series for the evolution of the SST signal of the current over the last... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00156/26738/24815.pdf |
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| Puillat, Ingrid; Carlier, Antoine; Facq, Jean-valery; Rubio, Anna; Lazure, Pascal; Delauney, Laurent; Petihakis, George; Karlson, Bengt; Artigas, Felipe; Farcy, Patrick. |
| A key message of the JERICO-RI consortium (2014): “The complexity of the coastal ocean cannot be well understood if interconnection between physics, biogeochemistry and biology is not guaranteed. Such integration requires new technological developments allowing continuous monitoring of a larger set of parameters”. In agreement with this consideration, several new observing systems are developed, tested and deployed in the framework of the JERICO-NEXT H2020 project, amongst which a few of them will be presented as well as some preliminary results after the first deployments. Focus will be given on coastal transports and hydrology and on benthic biodiversity. In the first case, we will present a low cost 2D moored system dedicated to acquire vertical... |
| Tipo: Text |
Palavras-chave: JERICO; JERICO-NEXT; Coastal; Ocean Observing System (OOS); Harmonization. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00437/54866/56359.pdf |
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| Planque, Benjamin; Lazure, Pascal; Jegou, Anne-marie. |
| A complex set of hydrodynamical structures co-exist over the Bay of Biscay continental shelf. These structures, which can spread over a limited spatial range (10s of km) and last for periods ranging from days to months, influence the rates and nature of biological production. They need to be accurately described before the mechanisms linking hydrodynamics to production can be unraveled. Such description generally requires not only 3D observations of hydrological fields (temperature, salinity, density), but also a description of how these fields vary with time. This is hardly achievable with current means of field observation but can be mimicked by hydrodynamic model simulations. Using simulations from a 3D hydrodynamic model, we developed a methodology... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Hydrology; Hydrodynamic model; Spring; Typology. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00000/10933/7575.pdf |
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| Lazure, Pascal; Garnier, Valerie; Dumas, Franck; Herry, Christelle; Chifflet, Marina. |
| The hydrology of the Bay of Biscay was investigated using the regional ocean model MARS3D (Model for Application at Regional Scale). The simulated hydrology is compared to a set of various data encompassing monthly climatology, remote sensing SST CTD casts, and coastal salinity measurements. Special focus was put on the validation over the continental shelf. This paper reports that despite some misfits, the climatological hydrology and its seasonal variability are correctly simulated. Various statistics computed over the period from 1999-2004 highlight different aspects of the hydrology. The biases and root mean square errors (RMSE) remain very weak at all depths when comparing salinity (< 0.1 and < 0.6psu respectively). The predicted temperature... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Regional model; Performance assessment. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11079/9282.pdf |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| Variability in anchovy recruitment in Biscay is temptatively explained using variables from the stock and from the environment during the ichtyoplankton phase. Anchovy recruitment depends on many different processes : weight of adults and proportion of multiple spawners (age 2), river discharges, upwelling events at the coast and at the shelf break. Meteorological variables (wind, rain, tempe rature ) are forcing effects on the sea but they are not the effective processes that govern the production in the sea. So they do not relate directly to the survival of larvae and to recruitment. In Biscay, many different physical processes are active and used by anchovy which spawns in different physical systems (river plumes, open ocean enrichment systems).... |
| Tipo: Text |
Palavras-chave: Bio-physical coupling; Recruitment; Anchovy; Hdrodynamics; Step by step regression. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00391/50190/50814.pdf |
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| Bernard, Ismael; Duchene, Julie; Hily, Christian; Lazure, Pascal; Pouvreau, Stephane; Boudry, Pierre. |
| En complément du rapport final (Anonyme (2014). PERLE. Programme d'expérimentation et de recherche sur l'huître plate Ostrea edulis. Rapport final de l'ensemble du projet 2011-2014. http://archimer.ifremer.fr/doc/00248/35932/), ce rapport présente l'étude de la phase de dispersion des larves en rade de Brest et analyse le lien entre la quantité de larves émises et la quantité de larves captées. Ce lien, qui possède une forte composante spatiale, est appelé connectivité. Il est sous l’influence de la dispersion et de la survie des larves mais seule la dispersion larvaire, avec différents forçages biophysiques du milieu, a été considérée ici. Les effets de la localisation des zones d’émission et de captage, du comportement des larves, du vent ou de la durée... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00251/36233/34793.pdf |
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| Lazure, Pascal; Salomon, Jean-claude. |
| The marine circulation between Quiberon and Noirmoutier is due to the combined effects of the tides, winds and density circulation induced by the discharges of the Vilaine and Loire rivers. These effects have been studied with two mathematical models, a two-dimensional (vertically integrated) one and a three-dimensional one. The tide has been shown to be the most important phenomenon at short time scale. Its effects are locally variable mainly because of topographic control. The tidal influence decreases significantly at long time scale and the residual circulation depends mainly on meteorological and hydrological conditions. The wind-induced circulation is mostly three-dimensional and appears locally to be the main dynamic process. During high flood, the... |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00245/35578/34111.pdf |
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| Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes. |
| Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf |
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| Lazure, Pascal. |
| The Bay of Biscay continental shelf is the site of a variety of physical processes, none of which are permanently dominant. The variability of the circulation from daily to interannual scales has been explored through both modelling and observation. Emphasis will be placed on one of the peculiarities of the Atlantic Plateau: the importance of river flows whose catchment areas represent half of the metropolitan territory. The mixing of these fresh waters with marine waters forms plumes that oscillate according to winds and general circulation. Increasingly refined modelling and a growing number of observations now make it possible to describe their fate and their extension as far as the English Channel. The general circulation on the shelf is weak and... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00610/72176/70951.pdf |
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| Registros recuperados: 99 | |
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