|
|
|
| Registros recuperados: 289 | |
|
|
| Ribeiro, Lourenço; Le Bris, Anthony; Hernandez Farinas, Tania; Buchet, Remi; Dutertre, Mickaël; Metzger, Edouard; Rosa, Philippe; Gernez, Pierre; Lerouxel, Astrid; Barille, Laurent. |
| In order to establish the ecological status of water bodies, the European Water Framework Directive (WFD) is based on the evaluation of a number of biological quality elements, as well as physical parameters supporting the biology. In estuaries, phytoplankton monitoring was not considered relevant because of the high turbidity characterizing the large metropolitan estuaries and the French overseas departments (Guyana). In this work, we considered the possibility of using microphytobenthos (MPB) as a biological indicator of the ecological status of estuaries. This activity report summarizes the actions undertaken in 2017 under an AFB / Université de Nantes convention, which is structured around two main axes: the first axis is based on the analysis of the... |
| Tipo: Text |
Palavras-chave: DCE; Diatomées benthiques; Diversité; Estuaires; Facteurs naturels; Gradient de perturbation; Loire; Bio-indication; Microphytobenthos; Pressions anthropiques; Télédétection.; Anthropogenic pressures; Benthic diatoms; Bio-indication; Diversity; Estuary; Loire; Microphytobenthos; Natural factors; Perturbation gradient; Remote sensing; WFD. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00446/55725/57376.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Saulquin, Bertrand; Gohin, Francis; Garello, Rene. |
| In this paper we define the method used to merge high resolution multi-sensor chlorophyll-a data on the Ireland-Biscay-Iberia Regional Ocean Observing System (IBI-ROOS) area at a resolution of 0.015 degrees. The method is based on geostatistics and is known as kriging. The merged variable is the anomaly of chlorophyll-a, the anomaly being defined for a day as the difference between the daily image and the mean historical field for that day. The used chlorophyll-a dataset is derived from the daily level-2 water leaving radiances of the Sea-viewing Wide Field of View Sensor (SeaWiFS) of the Orbview platform, the Moderate Resolution Imaging Spectroradiometer (MODIS) of the Aqua platform and the Medium Resolution Imaging Spectrometer Instrument (MERIS) of the... |
| Tipo: Text |
Palavras-chave: Remote sensing; Chlorophyll-a; Optimal interpolation; Kriging. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00014/12536/9568.pdf |
| |
|
| |
|
| |
|
|
| Golubkin, Pavel A.; Chapron, Bertrand; Kudryavtsev, Vladimir N.. |
| Wind-generated waves in the Kara, Laptev, and East-Siberian Seas are investigated using altimeter data from Envisat RA-2 and SARAL-AltiKa. Only isolated ice-free zones had been selected for analysis. Wind seas can be treated as pure wind-generated waves without any contamination by ambient swell. Such zones were identified using ice concentration data from microwave radiometers. Altimeter data, both significant wave height (SWH) and wind speed, for these areas were further obtained for the period 2002-2012 using Envisat RA-2 measurements, and for 2013 using SARAL-AltiKa. Dependencies of dimensionless SWH and wavelength on dimensionless wave generation spatial scale are compared to known empirical dependencies for fetch-limited wind wave development. We... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Satellite altimeter; Significant wave height; Wind speed. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00302/41330/40642.pdf |
| |
|
|
| Ardhuin, Fabrice; Stopa, Justin; Chapron, Bertrand; Collard, Fabrice; Husson, Romain; Jensen, Robert E.; Johannessen, Johnny; Mouche, Alexis; Passaro, Marcello; Quartly, Graham D.; Swail, Val; Young, Ian. |
| Sea state information is needed for many applications, ranging from safety at sea and on the coast, for which real time data are essential, to planning and design needs for infrastructure that require long time series. The definition of the wave climate and its possible evolution requires high resolution data, and knowledge on possible drift in the observing system. Sea state is also an important climate variable that enters in air-sea fluxes parameterizations. Finally, sea state patterns can reveal the intensity of storms and associated climate patterns at large scales, and the intensity of currents at small scales. A synthesis of user requirements leads to requests for spatial resolution at kilometer scales, and estimations of trends of a few centimeters... |
| Tipo: Text |
Palavras-chave: Sea state; Waves; Altimeter; SAR; Swell; Remote sensing; Buoy; Microseisms. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00489/60090/63432.pdf |
| |
|
| |
|
|
| Méléder, Vona; Savelli, Raphael; Barnett, Alexandre; Polsenaere, Pierre; Gernez, Pierre; Cugier, Philippe; Lerouxel, Astrid; Le Bris, Anthony; Dupuy, Christine; Le Fouest, Vincent; Lavaud, Johann. |
| The gross primary production (GPP) of intertidal mudflat microphytobenthos supports important ecosystem services such as shoreline stabilization and food production, and it contributes to blue carbon. However, monitoring microphytobenthos GPP over a long-term and large spatial scale is rendered difficult by its high temporal and spatial variability. To overcome this issue, we developed an algorithm to map microphytobenthos GPP in which the following are coupled: (i) NDVI maps derived from high spatial resolution satellite images (SPOT6 or Pléiades), estimating the horizontal distribution of the microphytobenthos biomass; (ii) emersion time, photosynthetically active radiation (PAR), and mud surface temperature simulated from the physical model MARS-3D;... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Intertidal mudflat; Gross primary production; Remote sensing; NDVI; Modeling. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75531/76429.pdf |
| |
|
|
| Loubersac, Lionel; Dahl, Arthur; Collote, Pascal; Lemaire, Olivier; D'Ozouville, Laurent. |
| Damage from tropical cyclones can have major consequences for coral reef structure and ecology, as well as for human communities and human uses of coral reef resources. Remote sensing with high resolution multispectral satellite images can be used to asses large scale cyclone damages on coral reef areas. SPOT images of the almost atoll of AITUTAKI (Cook Islands) taken in june 1986 and february 1987 after the passage of Cyclone Sally near the island in january, were transformed and subjected to a textural analysis, and then compared to asses damage on the reefs and lagoon.New shallow sand and rubble deposits showed increased reflectance, while lower reflectance seemed associated with damage to reef structure, scouring in the lagoon, deposits of terrestrial... |
| Tipo: Text |
Palavras-chave: ICRS 6; Remote sensing; Reflectance; Stresses; Cyclones; Extreme events; Coral reef; Lagoon; Natural System; External Threats & Opportunities. |
| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/00143/25380/23518.pdf |
| |
|
| |
|
| |
|
|
| Dibarboure, G.; Le Traon, Pierre-yves; Galin, N.. |
| Sea surface height (SSH) measurements provided by pulse-limited radar altimeters are one-dimensional profiles along the satellite's nadir track, with no information whatsoever in the cross-track direction. The anisotropy of resulting SSH profiles is the most limiting factor of mesoscale SSH maps that merge the 1D profiles.This paper explores the potential of the cross-track slope derived from the Cryosphere Satellite-2 (CryoSat-2)'s synthetic aperture radar interferometry (SARin) mode to increase the resolution of mesoscale fields in the cross-track direction. Through idealized 1D simulations, this study shows that it is possible to exploit the dual SARin measurement (cross-track slope and SSH profile) in order to constrain mesoscale mapping in the... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Sampling; Satellite observations; Interpolation schemes; Inverse methods. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26305/24575.pdf |
| |
|
|
| Carlier, Antoine; Chauvaud, Laurent; Van Der Geest, Matthijs; Le Loc'H, Francois; Le Duff, Michel; Vernet, Marc; Raffray, Jean; Diakhate, Djibril; Labrosse, Pierre; Wague, Abdoulaye; Le Goff, Clement; Gohin, Francis; Chapron, Bertrand; Clavier, Jacques. |
| Banc d’Arguin (BA), Mauritania, is a nationally protected shallow gulf > 10,000 km2 between the Sahara desert and the upwelling system off the Mauritanian coast. In the southeast, BA consists of a 500 km2 tidal flat, the most important wintering site for shorebirds using the East Atlantic Flyway. The Mauritanian upwelling-driven phytoplankton production supports the most productive fisheries worldwide, but little is known about its trophic role in the functioning of the inshore BA food web. Using stable isotopes as trophic tracers to distinguish between upwelling-driven phytoplankton, open ocean phytoplankton, and benthic primary producers, we assessed the spatial extent to which the inshore BA food web is fuelled by upwelling-driven phytoplankton... |
| Tipo: Text |
Palavras-chave: Banc d'Arguin; West Africa; Food web structure; Remote sensing; Stable isotope; Upwelling. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00269/37999/36078.pdf |
| |
|
|
| Chen-zhang, David D.; Ruf, Christopher S.; Ardhuin, Fabrice; Park, Jeonghwan. |
| Global Navigation Satellite System Reflectometry (GNSS-R) is an active, bistatic remote sensing technique operating at L-band frequencies. GNSS-R signals scattered from a rough ocean surface are known to interact with longer surface waves than traditional scatterometery and altimetry signals. A revised forward model for GNSS-R measurements is presented which assumes an ocean surface wave spectrum that is forced by other sources than just the local near-surface winds. The model is motivated by recent spaceborne GNSS-R observations that indicate a strong scattering dependence on significant wave height, even after controlling for local wind speed. This behavior is not well represented by the most commonly used GNSS-R scattering model, which features a... |
| Tipo: Text |
Palavras-chave: Waves; Wind; Remote sensing. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00358/46909/46809.pdf |
| |
|
|
| Dransfeld, Steffen; Larnicol, Gilles; Le Traon, Pierre-yves. |
| Having already shown its potential of deriving the vector fields representing the ocean-surface advection from sequential 1.1-km-resolution local area coverage (LAC) Advanced Very High Resolution Radiometer (AVHRR) images, the maximum cross-correlation (MCC) technique here is applied to four 4.4-km-resolution global area coverage (GAC) AVHRR images. The resulting three vector fields are compared to the vector fields obtained from the LAC imagery corresponding to the same satellite passages. To quantify the reduction in accuracy inevitable when applying the method to the lower resolution imagery, the LAC vector fields were assumed to be error free. The deviation of the GAC vectors from the LAC vectors is expressed as percentage errors of the signal variance... |
| Tipo: Text |
Palavras-chave: Remote sensing; Marine technology; Infrared imaging; Image motion. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2319.pdf |
| |
|
|
| Menesguen, Alain; Gohin, Francis. |
| Accumulation of heat, or dissolved substances (nutrients, pollutants, etc.), or fine suspended particles in a water body is a key process in the functioning of aquatic ecosystems and their resistance to perturbations. In complex and wide open environments such as marine ecosystems, net accumulation is not only linked to the local renewal capacity of the water body, but also to the partial recirculation of water due to convective cells of various sizes. The English Channel, which can be considered as mainly dominated by tidal movements, exhibits such a complex quasi-permanent long-term circulation, made of a central "river" bordered with a lot of nested gyres. Here, we show that structures visible on satellite images of SST (Sea Surface Temperature),... |
| Tipo: Text |
Palavras-chave: Remote sensing; Suspended Particulate Matter; Chlorophyll; SST; Retention structures; Tidal residual circulation; Steady state model; English Channel. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2181.pdf |
| |
|
| |
| Registros recuperados: 289 | |
|
|
|
