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| Registros recuperados: 99 | |
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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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| 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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| Donnet, Sebastien; Lazure, Pascal; Ratsimandresy, Andry; Han, Guoqi. |
| While the dynamics of narrow fjords, i.e. narrow with respect to their internal Rossby radius, have been widely studied, it is only recently that interest sparked in studying the physics of broad fjords due to their importance in glacial ice melting (in Greenland, especially). Here, we present a comprehensive set of data collected in Fortune Bay, a broad, mid-latitude fjord located on the Northwest Atlantic shores. Aside from being wide (15–25 km width) and deep (600 m at its deepest), Fortune Bay also has the characteristics of having steep slopes, weak tides and of being strongly stratified from spring to fall. Thus, and since strong along-shore winds also characterise the region, this system is prone to interesting dynamics, generally taking the form of... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74635/74529.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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| Pous, Stephane; Lazure, Pascal; Carton, Xavier. |
| Previous studies modeling the circulation and thermohaline structure in the Persian Gulf have suggested that interannual variability and vertical mixing processes could explain the model biases when compared to the few observations available. Here, a realistic, interannual, high-resolution model of the Persian Gulf is presented, validated against observations and then used to describe the intraseasonal to interannual variability in the circulation, water mass formation and exchange through the Strait of Hormuz. Sensitivity experiments to model settings, in particular vertical mixing parameterizations, have been performed in order to have the best comparison with all available observations. Main circulation and water mass characteristics correspond well to... |
| Tipo: Text |
Palavras-chave: Persian Gulf; Strait of Hormuz; Numerical model; Hydrology; Currents; Interannual variability. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00244/35563/35324.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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| Pous, Stephane; Carton, Xavier; Lazure, Pascal. |
| A homogeneous shallow-water model with free surface is used to model the tidal circulation in the Persian Gulf. The numerical finite-difference model includes harmonic diffusion of horizontal momentum and quadratic bottom friction, it has a 9 km mesh size and it is forced by 7 tidal components at its southern boundary. High precision bathymetric data are used to obtain the bottom topography. The numerical model is run for more than a year. The results are the following: 1) The model accurately reproduces the tidal phase and amplitude observed at 42 tidal gauges in the region. This accuracy is attributed to the presence of the 7 components which are able to interact nonlinearly; 2) The amphidromic points are also well positioned by the model due to a proper... |
| Tipo: Text |
Palavras-chave: Persian Gulf; Barotropic Tide; Hydrodynamical Modeling; Comparison with Data. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00284/39520/38013.pdf |
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| Pous, Stephane; Carton, Xavier; Lazure, Pascal. |
| A shallow-water model, coupled with a three dimensional, hydrostatic ocean model, is used to study the wind induced circulation, and the Shatt-al-Arab river plume expansion, in the Persian Gulf. The models are used in an idealized configuration. The following results are obtained: 1) with northwesterly winds, a double gyre is formed: this gyre is cyclonic in the south and anticyclonic in the north. Southeastward currents flow along the Iranian and Arabian coast where the wind stress at the surface dominates the pressure gradient related to the free surface slope, and conversely in the deeper region of the Gulf; 2) In the eastern part of the Gulf, the cyclonic gyre intensifies, as observed and reported in the literature; 3) For northwesterly winds, the... |
| Tipo: Text |
Palavras-chave: Persian Gulf; Wind-Induced Circulation; Hydrodynamical Modeling. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00284/39521/38014.pdf |
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| Lazure, Pascal; Jegou, Anne-marie; Kerdreux, Michel. |
| The Bay of Biscay is characterised by large fresh water inputs from two major rivers, the Loire and the Gironde, with a mean discharge of about 900 m(3)/s. To describe the spatial and temporal variability of the Loire and Gironde plumes, continuous salinity measurements were made at 4 locations on French coastal islands over periods lasting at least two years. These islands are located at a distance from the large local gradients linked to local inputs. Whereas sea surface salinity in the centre of the Bay of Biscay is 35.6, salinities at the coast vary between about 35 in summer to occasionally less than 30 in late winter or in spring. Minimum salinities do not occur at the same time along the coast, indicating a strong spatial gradient. Near the Loire... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Continental shelf; River plume; Seasonal variability; Salinity; Hydrology. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3957.pdf |
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| Doré, Justine; Chaillou, Gwénaelle; Poitevin, Pierre; Lazure, Pascal; Poirier, André; Chauvaud, Laurent; Archambault, Philippe; Thébault, Julien. |
| Despite its major role as a global climate regulator, little is known about the recent evolution of the North Atlantic Ocean, especially prior to the fifties, principally because of the lack of long-term instrumental data. Moreover, the North Atlantic Ocean is undergoing rapid changes at the physical scale leading to modifications at the biological scale increasing interest to monitor the environment. The phytoplankton is the base of the ocean life and its perturbation can lead to further changes in the food chain. Recording its dynamics implies to observe both its spatial and temporal variations. This study brings forward the use of the Ba/Ca ratio from shells of the long-living bivalve Arctica islandica collected in the Northwestern Atlantic Ocean near... |
| Tipo: Text |
Palavras-chave: A. islandica; Ba/Ca; Master chronology; Cross-dating; Chlorophyll a; Northwestern Atlantic. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71881/70576.pdf |
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| Clavier, Jacques; Chauvaud, Laurent; Amice, Erwan; Lazure, Pascal; Van Der Geest, Matthijs; Labrosse, Pierre; Diagne, Ahmed; Carlier, Antoine; Chauvaud, Sylvain. |
| Benthic primary production and respiration were investigated at 4 sites representative of the major coastal communities bordering the Sahara Desert in the Banc d'Arguin, Mauritania, Western Africa. These sites correspond to intertidal Zostera noltii beds (270 km(2)), intertidal bare sediments (88 km(2)), subtidal Cymodocea nodosa beds (374 km(2)), and subtidal bare sediments (311 km(2)). At each site, production-irradiance relationships were established in situ in November 2008 and January 2010, and used to calculate daily carbon fluxes for these communities. In intertidal areas, compared to emersion, the gross maximal photosynthetic rates for Z. noltii bed and bare sediment communities were on average 8-and 7-fold higher during immersion, respectively;... |
| Tipo: Text |
Palavras-chave: Seagrass; Carbon metabolism; Intertidal; Subtidal; Respiration; Primary; Production; Western Africa. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00189/29987/28460.pdf |
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| Lazure, Pascal; Huret, Martin; Gohin, Francis; Menesguen, Alain; Lecornu, Fabrice; Le Traon, Pierre-yves; Thomin, Pascale; Jegou, P.; Baraer, F.; Corre, Gilles; Louazel, Stephanie; Equipe projet PREVIMER. |
| Sommaire * Météo et débits des fleuves.....2 * Caractéristiques des masses d’eau côtières..............5 * Production biologique............11 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15 |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00242/35367/33866.pdf |
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| Lazure, Pascal; Huret, Martin; Gohin, Francis; Sourisseau, Marc; Saulquin, Bertrand; Lecornu, Fabrice; De Roeck, Yann-herve; Legrand, Jacques; Thomin, Pascale; Aoustin, Yannick; Jegou, P.; Baraer, F.; Le Stum, M.; Louazel, Stephanie; Equipe projet PREVIMER. |
| Sommaire * Météo, états de mer et débits des fleuves.....................2 * Caractéristiques des masses d’eau côtières..............6 * Production biologique............11 * Les faits marquants................12 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15 |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00242/35360/33860.pdf |
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| Registros recuperados: 99 | |
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