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| Registros recuperados: 99 | |
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| Batifoulier, Francois; Lazure, Pascal; Bonneton, Philippe. |
| Two hydrodynamic surveys based on acoustic Doppler current profiler (ADCP) and drift buoys measurements taken in summer 2008 and 2009 revealed poleward coastal jets of up to 32 cm s(-1) that lasted up to 22 d along the Aquitaine shelf in the southeastern area of the Bay of Biscay. A strong increase in bottom temperature was associated with these currents, up to 4 degrees C in 5 d at 54 m depth. These observations occurred after a few days of westerlies, cross-shore winds which were thought to have only a limited impact on longshore circulation. Here, the MARS3D hydrodynamic model was used with a schematic bathymetry of the southeastern area of the Bay of Biscay to reproduce and analyze these coastal jets. Simulations revealed that the triggering mechanism... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00074/18569/16123.pdf |
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| Charria, Guillaume; Repecaud, Michel; Quemener, Loic; Menesguen, Alain; Rimmelin-maury, Peggy; L'Helguen, Stephane; Beaumont, Laurence; Jolivet, Aurelie; Morin, Pascal; Mace, E; Lazure, Pascal; Le Gendre, Romain; Jacqueline, Franck; Verney, Romaric; Marie, Louis; Jegou, Paul; Le Reste, Serge; Andre, Xavier; Dutreuil, Vincent; Regnault, Jean-pierre; Jestin, Herve; Lintanf, Herve; Pichavant, Pascal; Retho, Michael; Allenou, Jean-pierre; Stanisiere, Jean-yves; Bonnat, Armel; Nonnotte, Lidwine; Duros, Wenceslas; Tarot, Stephane; Carval, Thierry; Le Hir, Pierre; Dumas, Franck; Vandermeirsch, Frederic; Lecornu, Fabrice. |
| To design a prototype for an Integrated Ocean Observing System (IOOS), at least three components are mandatory: a modeling platform, an in situ observing system and a structure to collect and to disseminate the information (e.g. database, website). The PREVIMER project followed this approach and in order to sustain model applications, PREVIMER has developed, funded and organized part of in situ observing networks in the Bay of Biscay and the Channel. For a comprehensive system, focus was addressed on fi xed platforms (MAREL MOLIT, MAREL Iroise, Island network and D4 for sediment dynamics), ships of opportunity (RECOPESCA program and FerryBoxes), and coastal profi lers (ARVOR-C/Cm). Each system is briefl y described and examples of scientifi c results... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30785/29143.pdf |
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| Ropert, Michel; Lazure, Pascal. |
| La phase opérationnelle du projet HYDRORUN, initié fin 2009, a débuté en avril 2010. A l'échéance de fin 2012, HYDRORUN devrait proposer aux décideurs et aux acteurs du littoral Réunionnais de nouveaux outils d'aide à la décision en matière de préservation et de gestion de la qualité des eaux littorales. Ces outils reposent sur une plate-forme de modélisation hydrodynamique centrée sur 6 modèles mars 3d, à mailles de 100 m, couvrant l'ensemble du littoral de l'île de La Réunion. Au terme de la première année du projet, le travail réalisé avec les différents partenaires du projet est présenté. Les emprises des modèles locaux ont été définies. Les données historiques de références ont été rassemblées. Les modèles atmosphériques et les modèles de houles sont... |
| Tipo: Text |
Palavras-chave: HYDRORUN; Modèle hydrodynamique; Courantologie; Réunion. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/14992/12324.pdf |
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| Kbaier-ben Ismail, Dhouha; Puillat, Ingrid; Lazure, Pascal. |
| Dans l’environnement marin, la température, la turbidité et la salinité sont des quantités importantes pour étudier l’écosystème. Beaucoup de champs montrent la haute variabilité pour une large gamme d'échelles spatiale et temporelle. Les séries temporelles sont souvent non-linéaires et non-stationnaires. Les auteurs considèrent ici les fluctuations du niveau de la mer, la salinité, la turbidité et la température enregistrés par le système MAREL Carnot de Boulogne-sur-Mer (France), qui est une bouée amarrée équipée d'appareils de mesure physicochimiques, qui fonctionnent dans des conditions continues et autonomes. Pour réaliser des analyses statistiques et spectrales adéquates, il est nécessaire de connaître la nature de la série temporelle considérée.... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00270/38076/36202.pdf |
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| Martin, Adrien; Boutin, Jacqueline; Hauser, Daniele; Reverdin, Gilles; Parde, Mickael; Zribi, Mehrez; Fanise, Pascal; Chanut, Jerome; Lazure, Pascal; Tenerelli, Joseph; Reul, Nicolas. |
| A renewal of interest for the radiometric L-band Sea Surface Salinity (SSS) remote sensing appeared in the 1990s and led to the Soil Moisture and Ocean Salinity (SMOS) satellite launched in November 2009 and to the Aquarius mission (launched in June 2011). However, due to low signal to noise ratio, retrieving SSS from L-band radiometry is very challenging. In order to validate and improve L-band radiative transfer model and salinity retrieval method used in SMOS data processing, the Cooperative Airborne Radiometer for Ocean and Land Studies (CAROLS) was developed. We analyze here a coastal flight (20 May 2009), in the Gulf of Biscay, characterized by strong SSS gradients (28 to 35 pss-78). Extensive in-situ measurements were gathered along the plane track.... |
| Tipo: Text |
Palavras-chave: L-band; Microwave radiometry; Remote sensing; Retrieval method; Sea surface salinity (SSS); Soil Moisture and Ocean Salinity (SMOS); Wind speed. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00079/18997/16600.pdf |
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| Lazure, Pascal; Pairaud, Ivane; Leizour, Stephane; Puillat, Ingrid. |
| Temperature distributions on continental shelves (depth < 150m) are often complex because the many physical processes induce very high spatial (both horizontal and vertical) and temporal variability. Temporal variability extends from a few tens of minutes for solitons (internal wave), a few hours for internal tide and inertial waves to a few days for upwelling or sub mesoscale dynamics. In the 1980s, satellites provided access to knowledge of surface temperatures. On the other hand, the internal temperature structure still requires in-situ measurements, which leads to the deployment of moorings at sea. These operations are often expensive and risky because the coastal zone is generally subject to intense activities such as fishing and sea conditions can... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00630/74245/73875.pdf |
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| Barnier, Bernard; Lazure, Pascal. |
| L'océanographie physique côtière a pour objet d'observer, de comprendre et de prévoir le fonctionnement hydrodynamique du milieu côtier, avec comme enjeux, dans le cadre d'applications pluridisciplinaires, la pollution côtière, la gestion et la préservation des écosystèmes et des ressources halieutiques, la contribution des zones côtières aux puits de carbone, l'hydrodynamique sédimentaire et les échanges eau - sédiments. Contrairement à l'océanographie du large, l'océanographie côtière n'a pas bénéficié de grands programmes internationaux (tel que le World Ocean Circulation Experiment -WOCE) pour structurer ses activités de recherche dans le domaine de l'observation et de la modélisation au niveau national ou international. De plus, les problèmes traités... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00020/13162/10212.pdf |
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| Ben Ismail, Dhouha Kbaier; Lazure, Pascal; Puillat, Ingrid. |
| In marine sciences, many fields display high variability over a large range of spatial and temporal scales, from seconds to thus ousands of years. The longer and longer recorded time series, with an increasing sampling frequency, in this field are often nonlinear, nonstationary, multiscale and noisy. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. The objective of this paper is to highlight time series analysis methods already applied in econometrics, signal processing, health,etc. to the environmental marine domain, assess advantages and inconvenients and compare classical techniques with more recent ones. Temperature, turbidity and salinity are important quantities for ecosystem studies. The... |
| Tipo: Text |
Palavras-chave: Continuous wavelet transform; Cross-correlation; Empirical mode decomposition; Hilbert Huang Transform; Stationarity; Time dependent intrinsic correlation; Time series; Wavelets. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00324/43519/43050.pdf |
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| Reverdin, G.; Boutin, J.; Martin, N.; Lourenco, A.; Bouruet-aubertot, P.; Lavin, A.; Mader, J.; Blouch, P.; Rolland,; Gaillard, Fabienne; Lazure, Pascal. |
| The accuracy of temperature measurements from drifters is first examined for 16 drifters (manufactured either by Metocean Data Systems or by Pacific Gyre) deployed with two temperature sensors in the tropical or North Atlantic Ocean. One of these sensors is the SST thermistor commonly used on Surface Velocity Program (SVP) drifters since the late 1980s; whereas the other sensor is a platinum temperature probe associated with a Seabird conductivity cell. The authors find (for 19 separate deployments) an average positive offset of the SST thermistor measurements in 17 out of 19 cases, exceeding 0.1 degrees C in five instances. Among the five drifters that were at sea for a year or more, two present a large trend in this offset (0.10 degrees and -0.10 degrees... |
| Tipo: Text |
Palavras-chave: Temperature; Sea surface temperature; Instrumentation; Sensors. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00012/12327/9112.pdf |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| A growth and survival model of the early life stages was run along virtual drift trajectories tracked in a hydrodynamic model to simulate the annual recruitment process of anchovy (Engraulis encrasicolus) in the Bay of Biscay (NE Atlantic). These biophysical simulations concerning three different years were analysed in order to investigate the influence of environment and spawning dynamics on the survival of larvae and juveniles. The location of space-time survival windows suggested major environmental mechanisms involved in simulated recruitment variability at the different scales - retention of larvae and juveniles in favourable habitats over the shelf margins and turbulence effects. These small-scale and meso-scale mechanisms were related to the... |
| Tipo: Text |
Palavras-chave: Turbulence; Retention; Recruitment; Physical biological interactions; Larval survival; IBM; Biscay; Anchovy. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3423.pdf |
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| Leblond, Emilie; Lazure, Pascal; Laurans, Martial; Rioual, Celine; Woerther, Patrice; Quemener, Loic; Berthou, Patrick. |
| Face to the lack of data to assess precisely the spatial distribution of catches and fishing effort and for the environmental characterization of the fishing area, Ifremer has been implemented since 2005 a new project, Recopesca. It consists in fitting out a sample of voluntary fishing vessels with sensors recording data on fishing effort (and at mid-terms catches) and physical parameters such as temperature or salinity. Recopesca aims at setting up a network of sensors, for scientific purposes, to collect data and improve resources assessment and diagnostics on fisheries, and environmental data required for ecosystem-based management initiatives. The challenge was to develop sensors with no trouble for the fishermen, tough enough to be fixed up on fishing... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00024/13500/10514.pdf |
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| Hartman, S.e.; Hartman, M. C.; Hydes, D.j.; Smythe-wright, D.; Gohin, Francis; Lazure, Pascal. |
| Unusually high chlorophyll values (~ 14 mg chl m− 3 at 5 m depth), recorded on a ship of opportunity (SOO) in July 2010, indicated the occurrence of a potential Harmful Algal Bloom (HAB) in the Western approaches of the English Channel. This bloom, located at 49.7°N, 3.2°W was observed via complementary datasets. These included data from samples collected for microscopic phytoplankton identification, information from satellite maps to follow geographical bloom development and in situ data to identify hydrographic factors related to bloom initiation. The relationships between chlorophyll-fluorescence, temperature, salinity and wind speed were examined. The intense summer bloom predominantly consisted of the dinoflagellate Karenia mikimotoi and followed an... |
| Tipo: Text |
Palavras-chave: Karenia mikimotoi; Harmful algae; Wind speed; Temperature; Low salinity water; French Atlantic rivers; English Channel; Ferry-box. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00199/31033/29437.pdf |
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| Kbaier-ben Ismail, Dhouha; Lazure, Pascal; Puillat, Ingrid. |
| Abstract. We consider the statistical analysis of high frequency sampled time series in nearshore waters of the Réunion island, located in the Indian Ocean 700 km east of Madagascar. We focus particularly on automatic measurements of current data sets at four different stations in the island. As this entire dataset is characterized by non-linearity and non-stationarity, two time-frequency decomposition methods, namely wavelets and Hilbert-Huang Transformation (HHT), are applied for the analysis of the entire dataset. Using the Continuous Wavelet Transform (CWT), some properties of the currents time series are determined. Then, the inertial wave and several low-frequency tidal waves are identified by the application of the Empirical Mode Decomposition (EMD)... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00270/38078/36206.pdf |
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| Planque, Benjamin; Lazure, Pascal; Jegou, Anne-marie. |
| Collecting hydrological observations over the whole Bay of Biscay continental shelf can require several weeks. As a result, the observations are not truly synoptic and the interpretation of hydrological structures is corrupted by the time-lags between observations at distinct locations. We evaluated the effects of non-synoptic sampling during a spring cruise (17 April to 13 May 2000), using outputs from 3D hydrodynamic models as a substitute for true synoptic sampling. We developed a method for clustering hydrological regions based on the vertical structure of the water column and temporal changes in hydrography. In parallel, outputs from the 3D model were compared with field observations. The results show that in spring 2000 the Bay of Biscay continental... |
| Tipo: Text |
Palavras-chave: Typology; Spatial temporal interactions; Hydrodynamics; Clustering analysis; Bay of Biscay. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3959.pdf |
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| Chauvaud, Laurent; Patry, Yann; Jolivet, Aurelie; Cam, Emmanuelle; Le Goff, Clement; Strand, Oivind; Charrier, Gregory; Thebault, Julien; Lazure, Pascal; Gotthard, Karl; Clavier, Jacques. |
| Understanding the relationship between growth and temperature will aid in the evaluation of thermal stress and threats to ectotherms in the context of anticipated climate changes. Most Pecten maximus scallops living at high latitudes in the northern hemisphere have a larger maximum body size than individuals further south, a common pattern among many ectotherms. We investigated differences in daily shell growth among scallop populations along the Northeast Atlantic coast from Spain to Norway. This study design allowed us to address precisely whether the asymptotic size observed along a latitudinal gradient, mainly defined by a temperature gradient, results from differences in annual or daily growth rates, or a difference in the length of the growing... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19861/17506.pdf |
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| Farrell, Hazel; Gentien, Patrick; Fernand, Liam; Lazure, Pascal; Lunven, Michel; Youenou, Agnes; Reguera, Beatriz; Raine, Robin. |
| Investigations into the phytoplankton of the Bay of Biscay in July 2006 revealed an extensive bloom of an unidentified haptophyte species. High-resolution sampling techniques identified the region in the vicinity of the mouth of the Loire estuary as an area of high (106–107 cells l−1) cell densities of the haptophyte in a thin sub-surface layer. This organism dominated the phytoplankton population regionally. Measurements of the vertical distribution of horizontal shear showed that the population, located at ca. 20 m depth, was confined to a layer lying between two density discontinuities with high shear. Physical measurements indicated that the population was being advected southeastwards, along the coast. Seaward spreading of the population was also... |
| Tipo: Text |
Palavras-chave: Haptophyte; Bay of Biscay; Horizontal dispersal; Thin layers. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00160/27129/25327.pdf |
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| Registros recuperados: 99 | |
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