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| Gohin, Francis; Saulquin, Bertrand; Oger-jeanneret, Helene; Lozac' H, L; Lampert, Luis; Lefebvre, Alain; Riou, Philippe; Bruchon, F. |
| The application of the new Water Framework Directive (WFD) of the European Union will require a dense and frequent monitoring of chlorophyll-a near the coast. Not counting the transitional water bodies located in the vicinity of estuaries, not less than seventy four coastal water bodies have to be monitored along the coast of the French Atlantic continental shelf and the English Channel. All the available data have to be gathered to implement a comprehensive monitoring scheme. To this purpose, we evaluate the capacity of ocean colour imagery to complete the conventional in situ data set collected in coastal networks. Satellite-derived chlorophyll-a concentration is obtained by the application of a coastal Look-Up-Table to water-leaving radiance of the... |
| Tipo: Text |
Palavras-chave: SeaWiFS; Coastal; Surveillance; Monitoring; Chlorophyll; Satellite. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4501.pdf |
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| Saulquin, Bertrand; Gohin, Francis. |
| A night-time series of sea surface temperature (SST) of the advanced very high-resolution radiometer (AVHRR) sensors provided by the AVHRR/Pathfinder was analysed over the period 1986-2006 in the English Channel. The studied area is characterized by a strong influence of the bathymetry on the mixing of the water column, mostly through the action of the tide and waves, leading to regional patterns in the SST fields. Another specific aspect of the area is the relatively large number of in situ measurements available from coastal stations. The remotely sensed SST data with fine spatial resolution and high-frequency measurements made at coastal stations have been analysed using a common model. The long-term evolution of SST has been defined in this study... |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12460/9881.pdf |
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| Saulquin, Bertrand; Gohin, Francis; Fanton D'Andon, Odile Fanton. |
| The new level-4 daily chlorophyll-a interpolated products described in this paper and freely available in the Copernicus-Marine Environment Service, aim at providing daily continuous fields (cloud-free) of satellite-derived chlorophyll-a surface concentration at two different resolutions: 4*4 km over the world and 1*1 km resolution over Europe. The multi-sensor daily analyses, by filling the cloudy pixels, provide high-frequency retrievals of chlorophyll-a which can contribute to a better monitoring of the phytoplankton biomass. From a methodological point of view our approach is a combination of a water-typed merge of chlorophyll-a estimates and an optimal interpolation based on the kriging method with regional anisotropic covariance models. These... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00481/59273/61990.pdf |
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| Lazure, Pascal; Huret, Martin; Gohin, Francis; Sourisseau, Marc; Saulquin, Bertrand; Lecornu, Fabrice; De Roeck, Yann-herve; Legrand, Jacques; Thomin, Pascale; Aoustin, Yannick; Jegou, P.; Baraer, F.; Le Stum, M.; Louazel, Stephanie; Equipe projet PREVIMER. |
| Sommaire * Météo, états de mer et débits des fleuves.....................2 * Caractéristiques des masses d’eau côtières..............6 * Production biologique............11 * Les faits marquants................12 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15 |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00242/35360/33860.pdf |
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| 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 |
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| Gohin, Francis; Van Der Zande, Dimitry; Tilstone, Gavin; Eleveld, Marieke A.; Lefebvre, Alain; Andrieux-loyer, Francoise; Blauw, Anouk N.; Bryère, Philippe; Devreker, David; Garnesson, Philippe; Hernandez Farinas, Tania; Lamaury, Yoann; Lampert, Luis; Lavigne, Héloïse; Menet-nedelec, Florence; Pardo, Silvia; Saulquin, Bertrand. |
| The variability of the phytoplankton biomass derived from daily chlorophyll-a (Chl-a) satellite images was investigated over the period 1998–2017 in the surface waters of the English Channel and the northern Bay of Biscay. Merged satellite (SeaWiFS-MODIS/Aqua-MERIS-VIIRS) Chl-a was calculated using the OC5 Ifremer algorithm which is optimized for moderately-turbid waters. The seasonal cycle in satellite-derived Chl-a was compared with in situ measurements made at seven coastal stations located in the southern side of the English Channel and in the northern Bay of Biscay. The results firstly showed that the satellite Chl-a product, derived from a suite of space-borne marine reflectance data, is in agreement with the coastal observations. For compliance with... |
| Tipo: Text |
Palavras-chave: Satellite remote-sensing; Ocean colour; Phytoplankton; Chlorophyll-a; English Channel; Bay of Biscay; Eutrophication assessment; European marine strategy framework directive. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00513/62514/66811.pdf |
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| Saulquin, Bertrand; Gohin, Francis; Garrello, Rene. |
| In this paper, we define the method that is used to merge high-resolution multisensor chlorophyll-a (chl-a) data on the Ireland-Biscay-Iberia Regional Ocean Observing System area from 1998 to the present at a resolution of 1.1 km. The method is based on geostatistics and is known as kriging. The merged variable is the daily anomaly of chl-a, with the anomaly being defined as the difference between the daily image and the mean historical field for the considered day. For each day, the continuous anomaly image is generated using the kriging method, and the mean historical field is then added to obtain the cloudless field of chl-a. The initial satellite chl-a data set used in the merging procedure is derived from the daily level-2 water leaving radiances of... |
| Tipo: Text |
Palavras-chave: Chlorophyll-a (chl-a); Kriging; Optimal interpolation; Remote sensing. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00029/14063/11369.pdf |
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