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| Registros recuperados: 99 | |
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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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| Pous, Stephane; Carton, Xavier; Lazure, Pascal. |
| Hydrological, ADCP, and drifting buoy data obtained during the GOGP99 Experiment in October and early November 1999 are analyzed to describe the Persian Gulf Water (PGW) core and the regional circulation in the Gulf of Oman. The warm and salty PGW core flows out of the Strait of Hormuz heading southeastward unto (25degrees20'N, 57degreesE), approximately. From there, it cascades down the continental slope, veers southwestward, and joins the Omani coast near (24degrees50'N, 56degrees50'E) to form a slope current. This PGW current has then thermohaline maxima on isopycnal sigma(0) = 26.5, near 220 m depth. Its thermohaline characteristics decrease along its progression to Ra's al Hadd ( and then offshore into the Arabian Sea) but maintain a sharp contrast... |
| Tipo: Text |
Palavras-chave: Persian Gulf Water outflow; Regional circulation; Gulf of Oman. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-390.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.... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00270/38076/36202.pdf |
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| Woillez, Mathieu; Fablet, Ronan; Tran-thanh Ngo,; Lalire, Maxime; Lazure, Pascal; De Pontual, Helene. |
| Numerous methods have been developed to geolocate fish from data storage tags. Whereas demersal species have been tracked using tide-driven geolocation models, pelagic species which undertake extensive migrations have been mainly tracked using light-based models. Here, we present a new HMM-based model that infers pelagic fish positions from the sole use of high-resolution temperature and depth histories. A key contribution of our framework lies in model parameter inference (diffusion coefficient and noise parameters with respect to the reference geophysical fields—satellite SST and temperatures derived from the MARS3D hydrodynamic model), which improves model robustness. As a case study, we consider long time series of data storage tags (DSTs) deployed on... |
| Tipo: Text |
Palavras-chave: Fish movement; Archival tagging; Migration; Population structure; Hidden Markov Model (HMM); State-space model. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00300/41097/40270.pdf |
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| Petitgas, Pierre; Magri Hoeltzener, Stephanie; Lazure, Pascal. |
| Modelling the vertical distribution of fish eggs is important when assessing fish stocks with egg production methods and for monitoring the reproductive potential of fish populations. Fish eggs are passive particles and their vertical distribution is determined by a few parameters such as egg density, egg diameter, wind- and tide-induced turbulence, and vertical hydrographic structure. A one-dimensional vertical biophysical, numerical model was developed which was adapted to the hydrography of shelf seas under the influence of tidal currents, wind-induced circulation, and river discharges. The biological part of the model parameterized the ascent velocity of the egg as a function of egg properties (diameter, density) and water properties (density,... |
| Tipo: Text |
Palavras-chave: Vertical distribution; Sprat; Sardine; Fish egg buoyancy; CUFES; Biophysical coupling; Anchovy. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2277.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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| 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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| 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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| Huret, Martin; Petitgas, Pierre; Struski, Caroline; Leger, Fabien; Sourisseau, Marc; Lazure, Pascal. |
| Overexploitation and climate change are increasingly causing unanticipated changes in marine ecosystems, such as higher variability in fish recruitment and shifts in species distribution, pressing for developing fisheries oceanography. In the meantime, operational oceanography rapidly progresses and its products become easy to access to a large community, among them fisheries scientists. Multiyear oceanographic reanalyses (hindcasts) were identified has a priority product by the ICES WG on Operational Oceanographic Products for Fisheries and Environment (WGOOFE). We performed a 37 years hindcast (1972-2008) run with a coupled physical-biogeochemical model (ECO-MARS3D) over the Bay of Biscay, using realistic meteorological and run-off forcing. We first... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00023/13432/10442.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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| 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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| Puillat, I; Lazure, Pascal; Jegou, Anne-marie; Lampert, Luis; Miller, P. |
| On the French continental shelf of the Bay of Biscay the variability of the surface salinity distribution has been mainly investigated at the seasonal and inter-annual scales. Here, new mesoscale features such as lower-salinity lenses observed in model results are investigated by hydrological measurements acquired during 8 cruises (1997-2000). These lenses are 50-80 km wide and similar to 30 m thick and occur during westerly to northerly wind events that push offshore the less saline water of river Plumes. These water masses detached from the coast are replaced with upwelled saltier water at the coast, so coastal upwelling is often observed at the same time along Landes and southern Brittany coasts. We show that in addition to the influence of seasonal and... |
| Tipo: Text |
Palavras-chave: River plume; Upwelling; Lens; Mesoscale; Salinity. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3958.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... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00156/26738/24815.pdf |
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| Huret, Martin; Sourisseau, Marc; Petitgas, Pierre; Struski, Caroline; Leger, Fabien; Lazure, Pascal. |
| Multiple year oceanographic simulations (hindcast) are identified as a priority oceanography product for fisheries and environment studies since they provide a unique continuous long-term dataset allowing integrated assessment of the ocean state and evolution. We performed a 37 year (1972–2008) hindcast run with a coupled physical–biogeochemical model in the Bay of Biscay. The coupled model and the hindcast configuration are described. A model skill assessment is performed with a large set of in-situ data. Average seasonal currents show major circulation patterns over the shelf. Among tracers, temperature and salinity have the best agreement, ahead of nitrates and silicates, chlorophyll, and finally phosphates and ammonium. For chlorophyll, improved... |
| Tipo: Text |
Palavras-chave: Physical-biogeochemical model; Hindcast; Skill assessment; Environmental indices; Seasonal pattern; Interannual variability; Fisheries oceanography; Bay of Biscay. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00114/22538/20237.pdf |
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| Tartinville, B; Deleersnijder, E; Lazure, Pascal; Proctor, R; Ruddick, Kg; Uittenbogaard, Re. |
| Several coastal ocean models have been used to compute the circulation on the Northwest European Continental Shelf. Five of them, developed within the European Union, are compared in the scope of an idealised three-dimensional test case, dealing with the geostrophic adjustment of a freshwater cylinder. As the central eddy adjusts, unstable baroclinic vortices start to grow. All the models are able to produce such unstable vortices. However, two of them produce an order-two instability, which is in accordance with a previous laboratory experiment, while the others exhibit an order-four instability. Using a simple scaling analysis, it is seen that the azimuthal wavenumber depends on the ratio of the kinetic energy to the available potential energy. It... |
| Tipo: Text |
Palavras-chave: Model intercomparison; Advection; Baroclinic instability; Geostrophic balance. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00448/55938/57485.pdf |
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| Registros recuperados: 99 | |
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