Consulta: creatorFacets:"Lazure, Pascal"
Registros recuperados: 99
Data/hora: 19/05/2024 10:35:28

3D modelling of seasonal evolution of Loire and Gironde plumes on Biscay Bay continental shelf
Provedor de dados: 5
Autores: Lazure, Pascal; Jegou, Anne-marie.
A 3D model of the Atlantic shelf has been developed and applied to study shelf dynamics and evolution of hydrology. The model takes the combined effects of tide, wind, river discharges and surface heat flux into account. Time scales vary from 1 day to several years. Following a brief description of the model and forcing variables, the behaviour of the Loire and Gironde plumes is described, first for winter and spring, then over a period of several years, under realistic forcing. The results show that plume evolution depends on the high Variability of river runoff and winds. Model simulations performed over 7 years (1990 to 1996) have highlighted several features of these plumes: 1) In early winter and periods of high river runoff, plumes usually spread...
Tipo: Text
Palavras-chave: Panache; Modélisation; Dynamique du plateau continental; Golfe de Gascogne; River plume; Modelling; Shelf dynamics; Bay of Biscay.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/1998/publication-847.pdf

A 37 years hindcast of a coupled physical-biogeochemical model and its use for fisheries oceanography in the Bay of Biscay
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00023/13432/10442.pdf

A 38 years hindcast of a coupled physical-biogeochemical model and derived indices for fisheries oceanography
Provedor de dados: 5
Autores: Huret, Martin; Petitgas, Pierre; Sourisseau, Marc; Struski, Caroline; Leger, Fabien; Lazure, Pascal.
Operational oceanography rapidly progresses and its products become easy to access to a large community, among them fisheries scientists. The products cover both near real-time environment information (on scales of days to weeks) but also retrospective analysis providing long time series of environment parameters. Here we describe a 38 years hindcast of a coupled physical-biogeochemical model of the Bay of Biscay as well as the indices and major information that were derived from it.
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00023/13454/10466.pdf

A coastal ocean model intercomparison study for a three-dimensional idealised test case
Provedor de dados: 5
Autores: 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

A comprehensive oceanographic dataset of a subpolar, mid-latitude broad fjord: Fortune Bay, Newfoundland, Canada
Provedor de dados: 5
Autores: 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
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00634/74635/74529.pdf

A HMM-based model to geolocate pelagic fish from high-resolution individual temperature and depth histories: European sea bass as a case study
Provedor de dados: 5
Autores: 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

A model of the general circulation in the Persian Gulf and in the Strait of Hormuz: Intraseasonal to interannual variability
Provedor de dados: 5
Autores: 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

A multi-decadal hindcast of a physical–biogeochemical model and derived oceanographic indices in the Bay of Biscay
Provedor de dados: 5
Autores: 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

A Process Study of the Tidal Circulation in the Persian Gulf
Provedor de dados: 5
Autores: 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

A Process Study of the Wind-Induced Circulation in the Persian Gulf
Provedor de dados: 5
Autores: 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

Advanced spectral analysis and cross correlation based on the empirical mode decomposition: application to the environmental time series
Provedor de dados: 5
Autores: Ben Ismail, Dhouha Kbaier; Lazure, Pascal; Puillat, Ingrid.
Abstract—In marine sciences, time series are often nonlinear and nonstationary. Adequate and specific methods are needed to analyze such series. In this paper, an application of the Empirical Mode Decomposition method (EMD) associated to the Hilbert Spectral Analysis (HSA) is presented. Furthermore, EMD based Time Dependent Intrinsic Correlation (TDIC) analysis is applied to consider the correlation between two nonstationary time series. Four temperature time series obtained from automatic measurements in nearshore waters of the Réunion island are considered, recorded every ten minutes from July 2011 to January 2012. The application of the EMD on these series and the estimation of their power spectra using the HSA are illustrated. The authors identify...
Tipo: Text
Palavras-chave: Augmented Dickey-Fuller tests; Cross correlation; Empirical mode decomposition (EMD); Hilbert spectral analysis (HSA); Hilbert-Huang transform (HHT); Stationarity; Time-dependent intrinsic correlation (TDIC); Time series; Wavelets.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00270/38077/36205.pdf

Analysis of salinity measurements near islands on the French continental shelf of the Bay of Biscay
Provedor de dados: 5
Autores: 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

Application of Hilbert-Huang decomposition to temperature and currents data in the Réunion island
Provedor de dados: 5
Autores: Kbaier-ben Ismail, Dhouha; Lazure, Pascal; Puillat Felix, Ingrid.
In marine sciences, time series are often nonlinear and nonstationary. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. We use the Hilbert-Huang Transform (HHT) for the spectral analysis of high frequency sampled time series in near shore waters of the Réunion island, located in the Indian Ocean 700 km east of Madagascar. We focus particularly on automatic measurements of sea level fluctuations, temperature records and current data sets at four different stations in the island. We look at the contribution of different Intrinsic Mode Functions (IMFs) obtained by the Empirical Mode Decomposition (EMD) and also compare the Hilbert spectra with the wavelet spectra. The inertial wave and several...
Tipo: Text
Palavras-chave: Cross correlation; Empirical mode decomposition (EMD); Hilbert spectral analysis (HSA); Hilbert-Huang transform (HHT); Stationarity; Time-dependent intrinsic correlation (TDIC); Time series; Wavelets.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00383/49392/49822.pdf

Assessment of Ba/Ca in Arctica islandica shells as a proxy for phytoplankton dynamics in the Northwestern Atlantic Ocean
Provedor de dados: 5
Autores: 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

Benthic metabolism in shallow coastal ecosystems of the Banc d'Arguin, Mauritania
Provedor de dados: 5
Autores: 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

Biophysical modelling of larval drift, growth and survival for the prediction of anchovy (Engraulis encrasicolus) recruitment in the Bay of Biscay (NE Atlantic)
Provedor de dados: 5
Autores: Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal; Grellier, Patrick.
Fish recruitment is the result of the integration of small-scale processes affecting larval survival over a season and large oceanic areas. A hydrodynamic model was used to explore and model these physical-biological interaction mechanisms and then to perform the integration from individual to population scales in order to provide recruitment predictions for fisheries management. This method was applied to the case of anchovy (Engraulis encrasicolus) in the Bay of Biscay (NE Atlantic). The main data available to investigate survival mechanisms were past growth (otolith) records of larvae and juveniles sampled at sea. The drift history of these individuals was reconstructed by a backtracking procedure using hydrodynamic simulations. The relationships...
Tipo: Text
Palavras-chave: Recruitment; Physical biological interactions; Individual based models; Biscay; Anchovy.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3422.pdf

Bulletin d'information PREVIMER - Informations et analyses des eaux côtières. Janvier Février 2010 - n°12
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00242/35367/33866.pdf

Bulletin d'information PREVIMER - Informations et analyses des eaux côtières. Mars Avril 2009- n°7
Provedor de dados: 5
Autores: 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
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00242/35360/33860.pdf

Circulation around La Reunion and Mauritius islands in the south-western Indian Ocean: A modeling perspective
Provedor de dados: 5
Autores: Pous, Stephane; Lazure, Pascal; Andre, Gael; Dumas, Franck; Halo, Issufo; Penven, Pierrick.
Circulation around both islands is dominated by westward propagating features The predominant time scale of variability of currents and SSH is 60 days There is local generation of eddies in the lee of the islands due to topography
Tipo: Text
Palavras-chave: Ocean circulation; Hydrodynamic model; La Reunion; Eddies; Rossby waves.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00195/30624/29073.pdf

Circulation on the shelf and the upper slope of the Bay of Biscay
Provedor de dados: 5
Autores: Le Boyer, Arnaud; Charria, Guillaume; Le Cann, Bernard; Lazure, Pascal; Marie, Louis.
Here, we used measurements taken with an array of 10 acoustic Doppler current profilers deployed from July 2009 to August 2011 to describe the tidally filtered circulation over the shelf and upper slope on the French side off the French coasts of the Bay of Biscay. The measurements provided an overview of the shelf and slope circulation throughout the entire water column over a large range of spatial and time scales. The average circulation over the shelf and upper slope of the Bay of Biscay was poleward following the topography with a speed of the order of 3 cm s(-1). This average circulation had marked seasonal variability. In summer, the currents were equatorward on the outer shelf near surface. Deeper in the water column, the flow remained poleward. In...
Tipo: Text
Palavras-chave: Bay of Biscay; Observation; Shelf and slope circulation; Vertical profile; ADCP; Wind driven circulation.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00139/24976/26395.pdf

Coastal mesoscale processes and their effect in phytoplankton distribution and community composition in the SE Bay of Biscay
Provedor de dados: 5
Autores: 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
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00635/74733/74723.pdf

Communication de l’information géographique maritime et côtière pour la gestion d’une crise environnementale : le naufrage du chimiquier « Ievoli Sun » en Centre Manche
Provedor de dados: 5
Autores: 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
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00089/20054/17695.pdf

Coupled 2-d and 3-d modeling of coastal hydrodynamics
Provedor de dados: 5
Autores: 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
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00101/21248/18862.pdf

Coupled air-sea interaction patterns and surface heat-flux feedback in the Bay of Biscay
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00088/19937/17605.pdf

Coupling physical and biogeochemical processes in the Rio de la Plata plume
Provedor de dados: 5
Autores: 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

Courantologie. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Desmare, Stéphanie.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Courants; Processus physiques; Circulation générale; Variabilité saisonnière; Courants de marée.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44003/43575.pdf

Courantologie. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Desmare, Stéphanie.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Courants; Processus physiques; Circulation générale; Variabilité saisonnière; Courants de marée.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43821/43395.pdf

Courantologie. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Desmare, Stéphanie.
Tipo: Text
Palavras-chave: Mers celtiques; Courants; Processus physiques; Circulation générale; Variabilité saisonnière; Courants de marée.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43925/43498.pdf

Daily scale wintertime sea surface temperature and IPC-Navidad variability in the southern Bay of Biscay from 1981 to 2010
Provedor de dados: 5
Autores: 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
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00156/26738/24815.pdf

Deployment of new observing systems within the JERICO-RI
Provedor de dados: 5
Autores: 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

Detecting hydrological landscapes over the Bay of Biscay continental shelf in spring
Provedor de dados: 5
Autores: 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

Development of a hydrodynamic model of the Bay of Biscay. Validation of hydrology
Provedor de dados: 5
Autores: 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 (&lt; 0.1 and &lt; 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

Développement de l'aquaculture à Saint-Pierre et Miquelon : le cas d'étude de la pectiniculture - approche et méthodologies
Provedor de dados: 5
Autores: Goraguer, Herle; Goulletquer, Philippe; Caisey, Xavier; Lazure, Pascal; Lajournade, M.; Lunven, Michel; Robert, Stephane; Rodriguez, Julien.
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00063/17413/14920.pdf

Does trace element composition of bivalve shells record utra-high frequency environmental variations?
Provedor de dados: 5
Autores: Poitevin, Pierre; Chauvaud, Laurent; Pecheyran, Christophe; Lazure, Pascal; Jolivet, Aurélie; Thebault, Julien.
Saint-Pierre and Miquelon (SPM) is a small archipelago where instrumental measures based on water column velocity and temperature profiles compiled comprehensive evidence for strong near-diurnal (25.8h) current and bottom temperature oscillations (up to 11.5 °C) which is possibly the largest ever observed — at any frequency — on a stratified mid-latitude continental shelf. The main objective of our study was to identify if Placopecten magellanicus can record on its shell these high frequency environmental variations. To this end, we have tried to identify proxies for water temperature and food availability through development of a new ultra-high resolution LA-ICPMS analyses method capable of resolving shell surface elemental composition with a 10 μm...
Tipo: Text
Palavras-chave: Ultra-high resolution LA-ICPMS; Placopecten magellanicus; Shell chemistry; Trace elements; Environmental change; Bivalve; Environmental proxies; North Atlantic; Saint-Pierre and Miquelon; Coastal trapped wave.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00612/72400/71345.pdf

Environmental and stock effects on the recruitment of anchovy in the Bay of Biscay : a multivariate analysis
Provedor de dados: 5
Autores: 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

Etude de la connectivité potentielle en rade de Brest : application au cas de l'huître plate, Ostrea edulis
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00251/36233/34793.pdf

Etude par modèles mathématiques de la circulation marine entre Quiberon et Noirmoutier
Provedor de dados: 5
Autores: 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
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00245/35578/34111.pdf

Étude préparatoire a une reconquête des niveaux de ressource en langouste royale (Palinurus elephas) en mer d'Iroise
Provedor de dados: 5
Autores: Latrouite, Daniel; Lazure, Pascal.
The study conducted in the framework of an agreement between Ifremer and the Local fisheries committee at Audierne is part of a project to restore spiny lobster Palinurus elephas stock levels in the Iroise Sea. It is supported by professional fishermen from Finistère and by the Regional fisheries committee of Brittany.  After a brief review of the way lobster stocks are managed worldwide, followed by the major biological and ecological features of red lobster and the state of fisheries in Europe and North Africa, the very poor state of the resource along French coast is borne out by the statistics of landings.   Various scenarios (not alternatives) to promote the rebuilding of the biomass are suggested:  minimum landing size increase, seasonal closure of...
Tipo: Text
Palavras-chave: Phyllosoma; Iroise; Stock; Rebuilding; Overfishing; Palinurus elephas; Red lobster; Phyllosomes; Iroise; Stock; Reconstitution; Surexploitation; Palinurus elephas; Langouste rouge.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/rapport-1198.pdf

Étude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest
Provedor de dados: 5
Autores: 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
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf

Exploration multi-échelle de la circulation côtière dans le golfe de Gascogne
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00610/72176/70951.pdf

Growth Response of Arctica Islandica to North Atlantic Oceanographic Conditions Since 1850
Provedor de dados: 5
Autores: Poitevin, Pierre; Thébault, Julien; Siebert, Valentin; Donnet, Sébastien; Archambault, Philippe; Doré, Justine; Chauvaud, Laurent; Lazure, Pascal.
The Northwest Atlantic is a key region with an essential role in global climate regulation, redistributing heat and influencing the carbon cycle. However, little is known about its evolution before 1950, mainly because of the lack of long-term instrumental measurements. The hard parts of long-lived marine biota hold the potential to extend instrumentally derived observation by several decades or centuries and enhance our understanding of global climate processes. Here, we investigate the effects of local, regional, and large-scale climate variability on the marine bivalve, Arctica islandica (Linnaeus, 1767) from Saint-Pierre and Miquelon (SPM). This archipelago lies at the boundary zone between the cold Labrador Current in the north and the warm Gulf...
Tipo: Text
Palavras-chave: Arctica islandica; Paleoecology; North Atlantic; Sub polar gyre; Labrador current; Bivalve; Sclerochronology; Climate change.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62050/66198.pdf

How does the connectivity between populations mediate range limits of marine invertebrates? A case study of larval dispersal between the Bay of Biscay and the English Channel (North-East Atlantic)
Provedor de dados: 5
Autores: Ayata, Sakina-dorothee; Lazure, Pascal; Thiebaut, Eric.
For many marine species, larval dispersal plays a crucial role in population persistence, re-colonization of disturbed areas, and distribution of species range limits through the control of population connectivity. Along the French Atlantic coast (NE Atlantic), a biogeographical transition zone has been reported between temperate and cold-temperate marine faunal assemblages. Hydrodynamics in this area are highly complex and variable including numerous mesoscale features (e.g. river plumes, fronts, upwellings, low salinity lenses), which could constrain larval transport and connectivity. In this context, the aim of this study was to assess how hydrodynamic conditions and biological traits influence larval transport and contribute to population connectivity...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00030/14174/11506.pdf

Hydrographical variability on the French continental shelf in the Bay of Biscay, during the 1990s
Provedor de dados: 5
Autores: Puillat, Ingrid; Lazure, Pascal; Jegou, Anne-marie; Lampert, Luis; Miller, P.
A synthesis of 9 years of hydrographic measurements, acquired during approximately 25 cruises (1992-2000) on the French continental shelf of the Bay of Biscay, is presented. The main focus is upon salinity distribution, as it is little known in this area. The whole of the data set covers I I months of the year, with some sampling fields repeated several times a year, for multiple years. This time-series allows temperature and salinity distributions to be studied together with their seasonal, inter-annual and mesoscale variability.   The seasonal trend in temperature can be described in three stages, which are in agreement with past studies. Thermal stratification occurs between May and mid-September in a layer similar to 50 m in thickness, whereas the...
Tipo: Text
Palavras-chave: Upwelling; Cold pool; River plumes; Seasonal variability; Salinity; Hydrography.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/2004/publication-779.pdf

Hydrology and circulation in the Strait of Hormuz and the Gulf of Oman - Results from the GOGP99 experiment: 1. Strait of Hormuz - art. no. C12037
Provedor de dados: 5
Autores: Pous, Stephane; Carton, Xavier; Lazure, Pascal.
In October and early November 1999, the GOGP99 experiment collected hydrological, currentmeter, tide recorder, thermistor and drifting buoy data near the Strait of Hormuz. Data analysis provides the water mass structure in the Strait: Persian Gulf Water (PGW) core is banked against the Omani coast, while Indian Ocean Surface Water (IOSW) lies near the Iranian coast. These water masses are most often covered by a homogeneous surface layer. Thermohaline characteristics of the PGW core decrease substantially downstream, from the Persian/Arabian Gulf to the Gulf of Oman. PGW and IOSW thermohaline characteristics and distribution also exhibit notable changes at periods shorter than a month as shown by repeated hydrological sections. The tidal signal measured...
Tipo: Text
Palavras-chave: Oceanography; Hydrology; Hormuz.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-389.pdf

Hydrology and circulation in the Strait of Hormuz and the Gulf of Oman - Results from the GOGP99 experiment: 2. Gulf of Oman - art. no. C12038
Provedor de dados: 5
Autores: 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

Identification de « paysages hydrologiques » dans les eaux marines sous juridiction française (France métropolitaine)
Provedor de dados: 5
Autores: Gailhard-rocher, Isabelle; Huret, Martin; Lazure, Pascal; Vandermeirsch, Frederic; Gatti, Julie; Garreau, Pierre; Gohin, Francis.
Dans le contexte de l’évaluation initiale des eaux communautaires demandée par la Directive cadre stratégie pour le milieu marin (DCSMM), les états membres sont chargés de décrire les types d’habitats dominants de la colonne d’eau pour chaque sous-région marine. La présente étude s’inscrit dans ce contexte et a pour objectif de décrire les principales structures hydrologiques de la colonne d’eau. Sur la base des données existantes et des travaux antérieurs, il s’agit de classer les masses d'eau en fonction de critères physiques (température, salinité, turbidité, stratification), reconnus d’intérêt pour les espèces pélagiques et l’écosystème en général, et ainsi de définir une cartographie de l’habitat pélagique moyen. Les données utilisées correspondent...
Tipo: Text
Palavras-chave: DCSMM; Habitat pélagique; Classification; Indices hydrologiques; Distribution des espèces; KeywordsMSFD; Pelagic Habitat; Clustering; Hydrological indices; Species distribution.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00069/18018/15547.pdf

Identification des flux de civelles (Anguilla anguilla) à partir des relations d’allométrie en fonction des conditions hydrodynamiques de l’estuaire de l’Adour
Provedor de dados: 5
Autores: De Casamajor, Marie-noelle; Prouzet, Patrick; Lazure, Pascal.
Biological data on glass eels (Anguilla anguilla) were collected during two successive sampling periods from November to March (1996-1997 and 1997-1998) on the Adour estuary. As for other estuaries, decrease in length (mean of 73.5 to 67.4 mm) and weight (mean of 3.5 to 2.6 dg) of glass eels were observed. Weight and length characteristics were used to identify groups of glass eels. These groups were well distinguished during the first sampling period but some overlaps appeared in the second one. Fluctuations of static allometry and similarity coefficients showed successive glass eels arrivals in the lower part of the estuary during the two seasons. We used fluctuations of the index of similarity in the second period to describe arrivals of glass-eels...
Tipo: Text
Palavras-chave: Biométrie; Modèle hydrodynamique; Flux migratoires; Civelle; Estuaire de l’Adour; Biometry; Hydrodynamic model; Migratory flow; Glass-eels; Adour estuary.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00188/29897/28346.pdf

Impact hydrodynamique de la mise en place d’un parc d’hydroliennes en Baie du Mont Saint-Michel
Provedor de dados: 5
Autores: Batifoulier, Francois; Kervella, Youen; Laborde, Renaud; Cuny, Jérôme; Caillaud, Matthieu; Lazure, Pascal; Cayocca, Florence.
Les fortes vitesses rencontrées à l’entrée de la Baie du Mont Saint-Michel font de cet environnement macro-tidal un endroit privilégié, en termes de ressources énergétiques, pour l’implantation d’une ferme d’hydroliennes. Afin d’établir plus précisément son potentiel énergétique et d’évaluer l’impact de l’implantation de telles machines sur son hydrodynamisme, une modélisation hydrodynamique de la Baie du Mont Saint-Michel est mise en oeuvre à l’aide du modèle de circulation régionale MARS3D (LAZURE &amp; DUMAS, 2008) dans sa version tridimensionnelle. La validation hydrodynamique de cette configuration est réalisée à partir de comparaisons à des mesures courantologiques récentes (KERVELLA, 2010). A partir de cette modélisation, une cartographie du...
Tipo: Text
Palavras-chave: Modélisation régionale; Hydroliennes; Baie du Mont Saint-Michel; Hydrodynamisme; Potentiel énergétique.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00195/30599/29055.pdf

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay
Provedor de dados: 5
Autores: Labry, Claire; Herbland, Alain; Delmas, Daniel; Laborde, P; Lazure, Pascal; Froidefond, J; Jegou, Anne-marie; Sautour, B.
Thermostratification and seasonal Light increase are generally considered the first causes of phytoplankton spring blooms in temperate waters. The objective of this study is to confirm the existence of winter phytoplankton blooms, responsible for the early exhaustion of phosphate, within the Gironde plume waters (southeast Bay of Biscay), and to understand what may initiate them so early. Two cruises, BIOMET 2 and BIOMET 3, were carried out respectively in early (8 to 21 January) and late winter 1998 (25 February to 11 March). An increase of phytoplankton biomass (chl a) between the 2 cruises and non-conservative nutrients observed in late winter confirm an early phytoplankton growth both in the Gironde plume and adjacent oceanic waters. Among factors that...
Tipo: Text
Palavras-chave: Vertical attenuation coefficient; Halostratification; Light availability; Winter blooms.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-810.pdf

Inventory and distribution of tritium in the oceans in 2016
Provedor de dados: 5
Autores: Oms, Pierre-emmanuel; Bailly Du Bois, Pascal; Dumas, Franck; Lazure, Pascal; Morillon, Mehdi; Voiseux, Claire; Le Corre, Cedric; Cossonnet, Catherine; Solier, Luc; Morin, Pascal.
Tritium concentrations in oceans were compiled from the literature, online databases and original measurements in order to determine the global distribution of tritium concentrations according to latitude and depth in all oceans. The total inventory of tritium decay corrected in 2016 has been estimated using evaluation of the natural and artificial contributions in 23 spatial subdivisions of the total ocean. It is determined equal to 26.8 ± 14 kg including 3.8 kg of cosmogenic tritium. That is in agreement with the total atmospheric input of tritium from nuclear bomb tests and the natural inventory at steady-state estimated from natural production rates in the literature (27.8–29.3 kg in the Earth). We confirm the global increase in tritium according to...
Tipo: Text
Palavras-chave: Radionuclide; Tracer; Database; Background concentration.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00470/58157/60653.pdf

Issues About Retrieving Sea Surface Salinity in Coastal Areas From SMOS Data
Provedor de dados: 5
Autores: Zine, S; Boutin, J; Waldteufel, P; Vergely, J.l.; Pellarin, T; Lazure, Pascal.
This paper aims at studying the quality of the sea surface salinity (SSS) retrieved from soil moisture and ocean salinity (SMOS) data in coastal areas. These areas are characterized by strong and variable SSS gradients [several practical salinity units (psu) on relatively small scales: the extent of river plumes is highly variable, typically at kilometric and daily scales. Monitoring this variability from SMOS measurements is particularly challenging because of their resolution (typically 30-100 km) and because of the contamination by the nearby land. A set of academic tests was conducted with a linear coastline and constant geophysical parameters, and more realistic tests were conducted over the Bay of Biscay. The bias of the retrieved SSS has been...
Tipo: Text
Palavras-chave: Soil Moisture and Ocean Salinity (SMOS) mission; Sea surface salinity (SSS) retrieval; L band radiometry; Coastal areas.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3643.pdf

La dispersion des apports de la Gironde sur le plateau continental. Données in situ, satellitales et numériques
Provedor de dados: 5
Autores: Hermida, J; Lazure, Pascal; Froidefond, Jm; Jegou, Anne-marie; Castaing, P.
Coastal waters are generally a product of mixing between continental and oceanic originated water masses. Near river mouth areas, as in the Gironde estuary, oceanic waters are modified by the influence of freshwater discharge that introduces suspended and dissolved substances, including pollutants. Within PNOC (Programme National d'Oceanographie Cotiere) our objective is to determine the extent of the influence of the Gironde estuary on to the Aquitanian continental shelf. Several cruises for collecting hydrological data have been carried out in this area. The data of every cruise were coupled with a NOAA-11 satellite passage. The recorded images have been analysed and were compared with the results given by a 3D mathematical model. The interaction among...
Tipo: Text
Palavras-chave: Hydrologie; Circulation; Eau côtière; Estuaire de la Gironde; Hydrology; Circulation; Coastal water; Gironde estuary.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/1998/publication-849.pdf

Large diurnal bottom temperature oscillations around the Saint Pierre and Miquelon archipelago
Provedor de dados: 5
Autores: Lazure, Pascal; Le Cann, Bernard; Bezaud, Marion.
Here, we report large, near-daily oscillations of near-bottom temperatures, with ranges of up to 11.5 °C at depths of 30–60 m in September 2011 around the Saint Pierre and Miquelon archipelago (south-eastern Canada). These oscillations were detected on velocity and temperature profiles from moorings in Miquelon Bay and on an array of near-bottom temperature sensors around the archipelago. The oscillations coincided with the seasonal stratification period. In addition to their remarkable range, they exhibited a near-diurnal period centred on the O1 tidal component (~26 h), contrasting with the dominant semi-diurnal sea-level periodicity in the area. They appear to be the manifestation of an internal wave, triggered by the diurnal surface tide and trapped by...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00457/56850/58687.pdf

Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018
Provedor de dados: 5
Autores: Pineau-guillou, Lucia; Lazure, Pascal; Woppelmann, Guy.
We investigated the long-term changes of the principal tidal component M2 over the North Atlantic coasts, from 1846 to 2018. We analysed 9 tide gauges with time series starting no later than 1920. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M2 variations are consistent at all the stations in the North East Atlantic (Newlyn, Brest, Cuxhaven), whereas some discrepancies appear in the North West Atlantic. The changes started long before the XXth century, and are not linear. The trends vary from a station to another; they are overall positive, up to 0.7 mm/yr. Since 1990, the trends switch from positive to negative values. Concerning the possible...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00635/74732/74722.pdf

Ligament, hinge, and shell cross-sections of the Atlantic surfclam (Spisula solidissima): Promising marine environmental archives in NE North America
Provedor de dados: 5
Autores: Poitevin, Pierre; Thebault, Julien; Schoene, Bernd R.; Jolivet, Aurelie; Lazure, Pascal; Chauvaud, Laurent.
The Atlantic surfclam (Spisula solidissima) is a commercially important species in North American waters, undergoing biological and ecological shifts. These are attributed, in part, to environmental modifications in its habitat and driven by climate change. Investigation of shell growth patterns, trace elements, and isotopic compositions require an examination of growth lines and increments preserved in biogenic carbonates. However, growth pattern analysis of S. solidissima is challenging due to multiple disturbance lines caused by environmental stress, erosion in umbonal shell regions, and constraints related to sample size and preparation techniques. The present study proposes an alternative method for describing chronology. First, we analyzed growth...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00444/55597/57229.pdf

Low salinity intrusions in the western English Channel
Provedor de dados: 5
Autores: Kelly Gerreyn, B; Hydes, D; Jegou, Anne-marie; Lazure, Pascal; Fernand, L; Puillat, I; Garcia Soto, C.
Low salinity (&lt; 35) surface waters (LSSW) at the southern entrance to the western English Channel (48.5 degrees N, 5.1 degrees W, near Ushant) were observed in late winter (March-April) in three successive years (2002-04) during near continuous ship of opportunity operations. The source of the LSSW is the northward spreading plumes from the Loire (47.5 degrees N, 2.5 degrees W) and Gironde (45.6 degrees N, 1.2 degrees W) along the French Atlantic coast. Fastest plume travel times were associated with northeasterly winds, consistent with Ekman theory. Differences between years in the mean winter (January-March) combined river discharges (D) was consistent with the minimum salinities (S-min) of the LSSW (2004: D = 4211 m(3) s(-1), S-min = 33.68; 2003: D =...
Tipo: Text
Palavras-chave: Bay of Biscay; English Channel; River plume; Ferrybox; Low salinity.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3524.pdf

Mastodon-2D. Deployment in Mediterranean Sea During Upcast field Experiment
Provedor de dados: 5
Autores: Pairaud, Ivane; Garnier, Valerie; Le Berre, David; Ravel, Christophe; Leizour, Stephane; Lazure, Pascal; Garreau, Pierre.
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00412/52310/53080.pdf

Mesoscale hydrological variability induced by northwesterly wind on the French continental shelf of the Bay of Biscay
Provedor de dados: 5
Autores: 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

Modèle hydro-sédimentaire du bassin de Marennes-Oléron : présentation et principaux résultats
Provedor de dados: 5
Autores: Raillard, Olivier; Le Hir, Pierre; Lazure, Pascal.
Depuis plusieurs années l'écosystème conchylicole de Marennes-Oléron est l' objet de modélisations de complexité croissante qui tendent à intégrer de plus en plus de processus physiques et biologiques (Bacher, 1989 ; Raillard, 1991) afin d'accroître le réalisme et le champ d'investigation de l'outil (Héral et al., 1991 ) . Confrontés au problème de la variabilité spatiale et temporelle des concentrations du matériel dissous et particulaire de l'eau, les travaux les plus récents ont pu mettre en évidence les limitations des modèles d'écosystème qui asservissent spatialement et temporellement la représentation des processus physiques à celle des mécanismes biologiques (Raillard, 1991). Le but de cette étude est de développer une modélisation de l'écosystème...
Tipo: Text
Palavras-chave: Modèle hydro-sédimentaire; Concentration particulaire; Concentration dissoute; Production primaire; Production secondaire; Bassin de Marennes Oléron; Charente Maritime Dep.
Ano: 1992
URL: http://archimer.ifremer.fr/doc/00102/21305/18918.pdf

Modélisation couplée physique-biogéochimie du golfe de Gascogne sur la période 1971-2007
Provedor de dados: 5
Autores: Huret, Martin; Struski, Caroline; Leger, Fabien; Petitgas, Pierre; Lazure, Pascal; Sourisseau, Marc.
Une simulation 'hindcast' de la dynamique physique et biogéochimique du golfe de Gascogne a été réalisée pour la période 1971-2007 à l'aide du modèle ECO-MARS3D. Ce modèle couplant physique et biogéochimie fournit une série longue de données simulées, moyennées ou intégrées sur 3 jours (température, salinité, sels nutritifs, phytoplancton, zooplancton), qui sont ensuite utilisées pour des calculs d'indices hydrologiques 2D synthétiques (indices méso-échelle : stratification, upwellings, surface tourbillonnaire ; indices biologiques : chlorophylle-a de surface, production primaire intégrée). Nous nous proposons dans ce document de présenter la configuration et les forçages utilisés pour cette simulation, et de lister les différentes variables sauvegardées...
Tipo: Text
Palavras-chave: Projet FP6 RECLAIM; Halieutique; Indices hydrologiques; Hindcast; ECO MARS3D; Modélisation couplée; Golfe de Gascogne.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/rapport-5164.pdf

Modélisation des blooms de Gymnodinium mikimotoï le long de la façade atlantique française : répartition spatiale
Provedor de dados: 5
Autores: Loyer, Sophie; Lazure, Pascal; Gentien, Patrick; Menesguen, Alain.
In order to study the occurrence of Gymnodinium mikimotoï bloom on the French Atlantic coast, a three-dimensional model of primary production was set up. The biological model was coupled to a hydrodynamic model previously developed at Ifremer, by the intermediary of transport, diffusion and heat fluxes. The cycles of three limiting elements for the phytoplankton growth were modelised: nitrogen, phosphorus and silicon. The second phase of the study aimed at reproducing the summer dinoflagellate blooms. In this new approach a model of the species Gymnodinium mikimotoï was coupled with the previous biomass model which provides the physical and chemical environments. The study focuses on the results obtained by this specific sub-model. The parametrisation was...
Tipo: Text
Palavras-chave: Turbulence; Dinoflagellés; Gymnodinium mikimotoï; Modèle; Nutriments; Turbulence; Dinoflagellate; Gymnodinium mikimotoï; Model; Nutrients.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00479/59100/61738.pdf

Modelling and numerical simulations of larval migration of the sole (Solea solea (L.)) of the Bay of Biscay. Part 1: modelling
Provedor de dados: 5
Autores: Ramzi, Azeddine; Arino, Ovide; Koutsikopoulos, Constantine; Boussouar, Ahmed; Lazure, Pascal.
A spatio-temporal model describing the dynamics of a population of sole is presented. The model is an extension to a 2D-space structure of a 1D model published by the three first authors. Spatial migration is modelled by an advection-diffusion second order operator with constant coefficients. The physical domain is represented by a half-plane with the coast as its boundary. A formula for estimating the proportion of eggs reaching the juvenile stage, depending upon climatic, transport, growth and mortality processes, is derived. Numerical results are deferred to elsewhere.
Tipo: Text
Palavras-chave: Recruitment; Diffusion and advection processes; Population dynamics; Recrutement; Processus de diffusion et d'advection; Dynamique de population.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/2001/publication-531.pdf

Modelling and numerical simulations of larval migration of the sole (Solea solea (L.)) of the Bay of Biscay. Part 2: numerical simulations
Provedor de dados: 5
Autores: Ramzi, Azeddine; Arino, Ovide; Koutsikopoulos, Constantine; Boussouar, Ahmed; Lazure, Pascal.
This paper is the second part of a work on the modelling of larval migration and growth fur the sole of the Bay of Biscay (Solea solea (L.)). The goal of the paper is twofold: first of all, it aims at presenting a numerical application of the formulae (concerning the recruitment rate) elaborated in the first paper. Results show a high sensitivity with respect to some parameters. Then, a comparison is made with a numerical model using a 3D circulation model provided by Ifremer.
Tipo: Text
Palavras-chave: Recruitment; Diffusion and advection processes; Population dynamics; Recrutement; Avection; Processus de diffusion; Dynamique de population.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/2001/publication-532.pdf

Modelling of oxygen and nitrogen cycling as a function of macrophyte community in the Thau lagoon
Provedor de dados: 5
Autores: Plus, Martin; Chapelle, Annie; Lazure, Pascal; Auby, Isabelle; Levavasseur, G; Verlaque, M; Belsher, Thomas; Deslous-paoli, Jean-marc; Zaldivar, J; Murray, C.
A three-dimensional model coupling physical and biological processes for the whole Than lagoon (Mediterranean coast of France) was developed in order to assess the relationships between macrophytes and the oxygen and nitrogen cycles. Ten species have been inserted as forcing variables in the model. Plankton dynamics, shellfish cultivation impact and mineralization of organic matter are also considered, as well as nutrient and oxygen exchanges between the sediment and the water column.   Simulations with and without the macrophytes have shown that the system can be characterized as having a highly structured pattern involving lagoon nitrogen and oxygen cycles. This pattern is created by the combined influence of macrophytes, watershed and oyster farming....
Tipo: Text
Palavras-chave: Thau lagoon; Biogeochemical cycles; Ecological modelling; Macrophytes.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-459.pdf

Modelling potential spawning habitat of sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) in the Bay of Biscay
Provedor de dados: 5
Autores: Planque, Benjamin; Bellier, Edwige; Lazure, Pascal.
Large amplitude variations in recruitment of small pelagic fish result from interactions between a fluctuating environment and population dynamics processes such as spawning. The spatial extent and location of spawning, which is critical to the fate of eggs and larvae, can vary strongly from year to year, as a result of changing population structure and environmental conditions. Spawning habitat can be divided into 'potential spawning habitat', defined as habitat where the hydrographic conditions are suitable for spawning, 'realized spawning habitat', defined as habitat where spawning actually occurs, and 'successful spawning habitat', defined as habitat from where successful recruitment has resulted. Using biological data collected during the period...
Tipo: Text
Palavras-chave: Sardine; Potential spawning habitat; Generalized additive models; Environmental effects; Bay of Biscay; Anchovy.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2180.pdf

Modelling water discharges and nitrogen inputs into a Mediterranean lagoon - Impact on the primary production
Provedor de dados: 5
Autores: Plus, Martin; La Jeunesse, I; Bouraoui, F; Zaldivar, J; Chapelle, Annie; Lazure, Pascal.
The Soil and Water Assessment Tool (SWAT model, 2001 Version) has been applied to the Than lagoon catchment area in order to simulate water discharges and nutrient inputs into the lagoon over a 10 years period (1989-1999), and to provide routing inflows to a previously developed lagoon ecosystem model. The watershed model has been calibrated and validated using measured data available for the two main rivers. The results indicate that the mean annual nitrogen inputs into the Thau lagoon is 117 +/- 57 tons y(-1), with the two main rivers, contributing for 80% of total annual nitrogen export. The variations of outputs to the lagoon are nonetheless important from 1 year to another. Due to the local agricultural practices and a reduced in-stream natural...
Tipo: Text
Palavras-chave: Thau lagoon; Primary production; Integrated modelling; Lagoon model; Watershed model.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1118.pdf

Modifcation du régime de salinité. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Paillet, Jerome.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Salinité; Variations naturelles; Impacts écologiques.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44046/43617.pdf

Modification du régime de salinité. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Paillet, Jerome.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Salinité; Variations naturelles; Impacts écologiques.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43860/43434.pdf

Modification du régime de salinité. Sous-région marine Méditerranée occidentale. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Paillet, Jerome.
Tipo: Text
Palavras-chave: Méditerranée; Salinité; Variations naturelles; Impacts écologiques.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00331/44229/79199.pdf

Modification du régime de salinité. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal; Paillet, Jerome.
Tipo: Text
Palavras-chave: Mers celtiques; Salinité; Variations naturelles; Evolution.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43964/43537.pdf

Modification du régime des courants. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Courants régionaux; Modifications; Impacts des activités marines.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44047/43618.pdf

Modification du régime des courants. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Courants régionaux; Modifications; Impacts des activités marines.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43861/43435.pdf

Modification du régime des courants. Sous-région marine Méditerranée occidentale. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal.
Tipo: Text
Palavras-chave: Méditerranée; Courants régionaux; Modifications; Impacts des activités marines.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00331/44230/43799.pdf

Modification du régime des courants. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Lazure, Pascal.
Tipo: Text
Palavras-chave: Mers celtiques; Courants régionaux; Modifications; Impacts des activités marines.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43966/43538.pdf

Modulation of sea surface temperature warming in the Bay of Biscay by Loire and Gironde Rivers
Provedor de dados: 5
Autores: Costoya, X.; Fernandez-novoa, D.; Decastro, M.; Santos, F.; Lazure, Pascal; Gomez-gesteira, M.
The influence of Loire and Gironde River discharges over the sea surface temperature (SST) in the eastern Bay of Biscay (0.6º–36.6ºW, 44.2º–47.8ºW) was analyzed by means of two complementary databases (MODIS and OISST1/4). The area influenced by river plume showed a different SST when compared with the adjacent oceanic area for the months when the plume attains its highest extension (December, January, and February). Ocean was observed to warm at a rate of approximately 0.3ºC dec−1 while temperature at the area influenced by the rivers cooled at a rate of −0.15ºC dec−1 over the period 1982–2014. The mere presence of a freshwater layer is able to modulate the warming observed at adjacent ocean locations since the coastal area is isolated from the rest of...
Tipo: Text
Palavras-chave: Loire; Gironde; SST; River plume; Warming modulation.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00311/42172/41472.pdf

Motility and autotoxicity in Karenia mikimotoi (Dinophyceae)
Provedor de dados: 5
Autores: Gentien, Patrick; Lunven, Michel; Lazure, Pascal; Youenou, Agnes; Crassous, Marie-pierre.
Karenia mikimotoi is one of the most common red-tide dinoflagellates proliferating in the eastern North Atlantic and around Japan. Kills of marine fauna are associated with its blooms. In mixed water columns it migrates vertically, while in stratified water columns, the population remains confined within pycnocline layers. Wind events, increasing mixing and agitation initiate declines in its populations. This paper is focused on the formulation of mortality rate relative to shear rate. Autotoxicity is demonstrated by the use of a synthetic toxin. Bioconvection observed in cultures allows the establishment of a trade-off between phototropism, which leads to the local accumulation of cells, and their autotoxicity, which would prevent cell concentration. The...
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2436.pdf

Movements of three alcid species breeding sympatrically in Saint Pierre and Miquelon, northwestern Atlantic Ocean
Provedor de dados: 5
Autores: Delord, Karine; Barbraud, Christophe; Pinaud, David; Letournel, Bruno; Jaugeon, Baptiste; Goraguer, Herle; Lazure, Pascal; Lormée, Hervé.
Among seabirds, alcids are particularly sensitive to bycatch in fisheries and oil pollution, yet their distribution at sea remains scarcely known in most of their breeding areas. GPS telemetry data of fifteen individuals of alcids (5 Razorbills 6 Common Murres and 4 Puffins) were analyzed to determine their distribution during the breeding period of 2016 at Saint Pierre and Miquelon Archipelago (SPM). Two analytical methods (threshold and a switching state-space model) were used to identify behavioral modes and foraging areas. We compared foraging movements and estimated the overlap between the species. Distribution and foraging covered an area located between SPM and Newfoundland. Our results revealed that the three species headed northward of their...
Tipo: Text
Palavras-chave: Telemetry; Behavioral models; Animal movement; Distribution overlap; Fratercula arctica; Alca torda; Uria aalge.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00588/70038/68016.pdf

One-dimensional biophysical modelling of fish egg vertical distributions in shelf seas
Provedor de dados: 5
Autores: 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

Pockmarks on the South Aquitaine Margin continental slope: The seabed expression of past fluid circulation and former bottom currents
Provedor de dados: 5
Autores: Michel, Guillaume; Dupre, Stephanie; Baltzer, Agnes; Ehrhold, Axel; Imbert, Patrice; Pitel, Mathilde; Loubrieu, Benoit; Scalabrin, Carla; Lazure, Pascal; Marie, Louis; Geldof, Jean-baptiste; Deville, Eric.
Inactive and mostly elongated pockmarks of 100–200 m in dimension were recently discovered on the South Aquitaine Margin continental slope. They are distributed at water depths greater than 350 m in both interfluve and sediment-wave areas, and are strongly controlled by the sedimentary morphology and architecture. Water column and seafloor backscatter and sub-bottom profiler data do not exhibit present-day or past gas evidence, e.g., massive and continuous gas releases at the seabed and fossil methane-derived authigenic carbonates. It is thus proposed that the pockmarks originated from a shallow source and result from relatively recent and short-duration gas or water expulsion events. Former near-bottom currents may have contributed to the elongation of...
Tipo: Text
Palavras-chave: Pockmark; Fluid; Seabed morphology; Aquitaine slope; GIS; Currents.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00413/52491/53279.pdf

Poleward along-shore current pulses on the inner shelf of the Bay of Biscay
Provedor de dados: 5
Autores: Kersale, M.; Marie, Louis; Le Cann, B.; Serpette, A.; Lathuiliere, C.; Le Boyer, A.; Rubio, A.; Lazure, Pascal.
We analyzed strong events of coastal poleward along-shore currents above 10 cm s−1 and up to more than 50 cm s−1 on the inner shelf (50-80 m depth) of the Bay of Biscay (BoB) from the Spanish coast to the Brittany coast. We used data from four acoustic Doppler current profilers (ADCPs) deployed from July 2009 to August 2011. The goal of this study was to analyze current variability at meso- and subinertial scales and their generation mechanisms. These currents occurred all year long and were classified into three types. Events occurring principally in the southern part of the BoB were classified as southern events. Bay-scale events were defined when strong poleward currents were detected over all the shelf, typically stronger on the Spanish and the...
Tipo: Text
Palavras-chave: Coastal jets; ADCP; Shelf circulation; Wind forcing; Coastal trapped waves; Bay of Biscay.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00299/40984/40075.pdf

Poleward coastal jets induced by westerlies in the Bay of Biscay
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00074/18569/16123.pdf

PREVIMER: A contribution to in situ coastal observing systems
Provedor de dados: 5
Autores: 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
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00197/30785/29143.pdf

Projet "HYDRORUN" : Etat d'avancement du projet Ifremer-OIHYDRORUN. Première année (2010)
Provedor de dados: 5
Autores: 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

Propriétés statistiques de la température, salinité et turbidité mesurées par la station MAREL Carnot dans les eaux côtières de Boulogne-sur-Mer (France)
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00270/38076/36202.pdf

Remote Sensing of Sea Surface Salinity From CAROLS L-Band Radiometer in the Gulf of Biscay
Provedor de dados: 5
Autores: 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

Report on the Mastodon2D mooring system
Provedor de dados: 5
Autores: Lazure, Pascal; Pairaud, Ivane; Leizour, Stephane; Puillat, Ingrid.
Temperature distributions on continental shelves (depth &lt; 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
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00630/74245/73875.pdf

Séminaire d'hydrodynamique côtière, Brest 15-17 septembre 2003. Compilation des interventions
Provedor de dados: 5
Autores: 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
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00020/13162/10212.pdf

Statistical properties and time-frequency analysis of temperature, salinity and turbidity measured by the MAREL Carnot station in the coastal waters of Boulogne-sur-Mer (France)
Provedor de dados: 5
Autores: 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

Temperature Measurements from Surface Drifters
Provedor de dados: 5
Autores: 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

The influence of environment and spawning distribution on the survival of anchovy (Engraulis encrasicolus) larvae in the Bay of Biscay (NE Atlantic) investigated by biophysical simulations
Provedor de dados: 5
Autores: 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

The Recopesca Project : a new example of participative approach to collect fisheries and in situ environmental data
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00024/13500/10514.pdf

The role of hydrographic parameters, measured from a ship of opportunity, in bloom formation of Karenia mikimotoi in the English Channel
Provedor de dados: 5
Autores: 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

The unexpected nature of the tidal currents observed off the Landes coast (44°N)
Provedor de dados: 5
Autores: Lazure, Pascal; Le Boyer, Arnaud; Marié, Louis.
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00315/42571/41941.pdf

Time-frequency analysis of currents data sampled at four stations in the Réunion island: application of EMD and wavelets
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00270/38078/36206.pdf

Typology of hydrological structures modelled and observed over the Bay of Biscay shelf
Provedor de dados: 5
Autores: 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

Variabilité du panache turbide de la Gironde par télédétection. Effets des facteurs climatiques
Provedor de dados: 5
Autores: Froidefond, Jm; Jegou, Anne-marie; Hermida, J; Lazure, Pascal; Castaing, P.
The Gironde estuary (France) discharges to the ocean an important amount of suspended particulate matter in the form of turbid plumes. The surface plume is more particularly studied from coastal oceanographic surveys and NOAA/AVHRR satellite data collected during a French programme of coastal oceanography (PNOC-Atlantic). The AVHRR reflectances are atmospherically corrected according to an algorithm based on the clear water concept. The comparison with suspended sediment concentrations are realised by direct and indirect calibrations. The correlations obtained show that at a same concentration the reflectance varies, probably because of varying particle (floc) size and composition. The shape and the surface measured from low resolution (4 km x 4 km) and...
Tipo: Text
Palavras-chave: Panache turbide; Télédétection; Hydrologie; Climatologie; Gironde; Turbid plume; Remote sensing; Hydrology; Climatology; Gironde.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/1998/publication-848.pdf

Variation in Size and Growth of the Great Scallop Pecten maximus along a Latitudinal Gradient
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19861/17506.pdf

Vertical and horizontal controls of a haptophyte thin layer in the Bay of Biscay, France
Provedor de dados: 5
Autores: 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

Wind-induced barotropic oscillations around the Saint Pierre and Miquelon archipelago (North-west Atlantic)
Provedor de dados: 5
Autores: Bezaud, Marion; Lazure, Pascal; Le Cann, Bernard.
We investigate the nearly barotropic oscillations recently observed around the Saint Pierre and Miquelon (SPM) archipelago. They were recorded by two ADCPs at about 30 m depth during winter and spring 2014. These oscillations were the dominant signal on the currents with a period of 2 to 4 days. Our analysis shows that these oscillations were triggered by the wind. To investigate these oscillations, a 2D numerical model was implemented at a regional scale. The results from a realistic simulation confirmed the impact of wind forcing on ocean dynamics in the region. They also showed amplification of these oscillations around SPM, particularly in the north-west of the archipelago and near Burin Peninsula. Analyses suggested the influence of continental shelf...
Tipo: Text
Palavras-chave: Barotropic modelling; Wind induced oscillations; Continental shelf wave; Saint Pierre and Miquelon archipelago; Newfoundland.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00606/71803/70291.pdf