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| Registros recuperados: 76 | |
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| Tilstone, Gavin; Mallor-hoya, Silvana; Gohin, Francis; Couto, Andre Belo; Sa, Carolina; Goela, Priscila; Cristina, Sonia; Airs, Ruth; Icely, John; Zuehlke, Marco; Groom, Steve. |
| Chlorophyll-a (Chl a) is a key parameter for the assessment of water quality in coastal and shelf environments. The availability of satellite ocean colour offers the potential of monitoring these regions at unprecedented spatial and temporal scales, as long as a high level of accuracy can be achieved. To use satellite derived Chl a to monitor these environments, it is imperative that rigorous accuracy assessments are undertaken to select the most accurate ocean colour algorithm(s). To this end, the accuracy of a range of ocean colour Chl a algorithms for use with Medium Imaging Resolution Spectrometer (MERIS) Level 2 (L2) Remote Sensing Reflectance (Rrs), using two different atmospheric correction (AC) processors (COASTCOLOUR and MERIS Ground Segment... |
| Tipo: Text |
Palavras-chave: Case 2 waters; Coastal waters; Shelf waters; Chlorophyll-a; North Sea; Ocean colour; Remote sensing; MERIS; English Channel; Mediterranean coast; Portuguese coast. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00359/46995/48634.pdf |
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| Buestel, Dominique; Dao, Jean-claude; Gohin, Francis. |
| The efficiency of the fishing drags in the Saint Brieuc Bay, Brittany, has been determined through the analysis of the tracks left on the seabed. The results, which focus mostly on the age class n°2 (2.5 years), show that the efficiency and the damages caused by the drags vary heavily according to the nature of the seabed. For soft bottoms, the average efficiency is 67 % and the global damage is 2 %. Concerning hard bottoms, the values are respectively 30 % and 17 %. These efficiency results combined with those of a dragging expedition in a set sector of the Saint-Brieuc Bay enable a direct assessment of the abundance. A result treatment method deriving from the geostatistical theory is used: it takes into account the spatial structure of the king scallop... |
| Tipo: Text |
Palavras-chave: Coquille Saint Jacques; Plongée; Dragage; Pecten maximus L.; Estimation stocks. |
| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/1985/acte-6536.pdf |
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| Kifani, S; Gohin, Francis. |
| A space-time approach is adopted in an attempt to understand changes in the availability of the central sardine stock along the northwestern Moroccan coast. The warming observed in 1987 and 1989, due to the decline in wind activity, seems to have some repercussions on sardine distribution. The decrease in upwelling activity seems to have favoured concentration in the vicinity of Safi, and thus rendered the sardines more vulnerable to the purse-seiners of this port. We seek to explain the failure of the link established by Belveze and Erzini (1983) between sardine availability and upwelling activity in thc northern area. Two hypotheses, taking into account the local hydrology or the tendency of pelagic species to aggregate in time and space, have been put... |
| Tipo: Text |
Palavras-chave: UPWELLING; MOROCCO; SARDINE; SEA SURFACE TEMPERATURE. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00100/21151/18770.pdf |
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| Auber, Arnaud; Gohin, Francis; Goascoz, Nicolas; Schlaich, Ivan. |
| A growing number of studies have documented increasing dominance of warm-water fish species (“tropicalisation”) in response to ocean warming. Such reorganization of communities is starting to occur in a multitude of local ecosystems, implying that tropicalisation of marine communities could become a global phenomenon. Using 32 years of trawl surveys in the Bay of Somme (English Channel, France), we aimed to investigate the existence of a tropicalisation in the fish community at the local scale of the estuary during the mid-1990s, a period where an exceptional temperature rise occurred in Northeast Atlantic. A long-term response occurred (with a major transition over 6 years) that was characterized by a marked diminution in the abundance of cold-water... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00374/48551/48873.pdf |
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| Guttler, Fabio; Niculescu, Simona; Gohin, Francis. |
| Based on multi-sensor optical remote sensing techniques, more than 80 medium and high spatial resolution satellite images were used for studying the turbidity patterns of Danube Delta waters. During a selected 4-year temporal coverage (2006 to 2009), the turbidity gradients were simultaneously analyzed in the delta plain lakes and in the Black Sea western-northwestern coastal zone. Two distinct, but complementary, methodologies for retrieving turbidity were employed, one for the lakes and the other for the coastal zone. After comparing the turbidity satellite-derived turbidity products with in-situ measurements, the inter-comparability of the products was independently verified. Then, through an integrative analysis, the initial hypothesis of turbidity... |
| Tipo: Text |
Palavras-chave: Turbidity; Satellite remote sensing; Danube Delta; Delta plain lakes; Western-northwestern Black Sea; Danube River plume; Phytoplankton; Macrophytes. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00135/24622/23607.pdf |
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| L'Heveder, Blandine; Speich, Sabrina; Ragueneau, Olivier; Gohin, Francis; Bryere, Philippe. |
| Seasonal Sea Surface Temperature (SST) changes in the Western English Channel have been estimated for the previous decades from high-resolution satellite data. Coastal seas, well separated from offshore waters by intense frontal structures, show colder SST by 1 to 2°C in summer. A significant warming trend is observed in the autumn season. This positive trend is stronger offshore, with an annual mean SST increase of 0.32°C/decade, but weaker in coastal waters (0.23°C/decade), where strong vertical mixing induced by tides and winds acts to reduce surface warming. The performance of an ensemble of CMIP5 climate model in simulating recent seasonal changes of SST in the region is estimated. The median of CMIP5 models reproduces very well the observed SST mean... |
| Tipo: Text |
Palavras-chave: SST; Climate change; Western English Channel; CMIP5; Regional study. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00350/46163/45861.pdf |
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| Samain, Jean-francois; Ropert, Michel; Bedier, Edouard; Soletchnik, Patrick; Mazurie, Joseph; Le Coz, Florence; Blin, Jean-louis; Mille, Dominique; Pajot, Régis; Haffray, Patrick; Bacher, Cedric; Grangere, Karine; Grangere, Karine; Pouvreau, Stephane; Bourles, Yves; Gohin, Francis; Woerther, Patrice; Boudry, Pierre. |
| Summer mortality has been reported in the Pacific oyster, Crassostrea gigas, for many years in Japan, US and Europe. It affects both adults and juveniles and the causes of this phenomenon are complex. Environmental, physiological or pathological putative causes were studied all over the world. Recently, the MOREST project ((MORtalitEStivale) a multidisciplinary project (2001-2005) focused on his problem led to a better understanding of this phenomenon in France. The results showed in these geographical conditions, the main interactions between the oysters, their environment and certain pathogens. |
| Tipo: Text |
Palavras-chave: Interaction model; Environmental parameters; Summer mortality; Crassostrea gigas; Pacific oyster. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/2006/acte-3476.pdf |
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| Bizzozero, Lucie; Gohin, Francis; Lampert, Luis; Fortune, Mireille; Cochennec-laureau, Nathalie. |
| Afin de répondre aux objectifs de la Directive Cadre sur l’eau, l’Ifremer met en oeuvre, en appui à l’Agence de l’eau Loire Bretagne, la surveillance de l’élément de qualité phytoplancton. Le suivi sur des points fixes et à une fréquence mensuelle ne permet pas de suivre l’ensemble des masses d’eau du bassin Loire Bretagne. C’est pourquoi l’évaluation de l’indicateur phytoplancton a été complétée par une évaluation à partir des images satellite, notamment sur les masses d’eau non suivies. L’indice biomasse (représenté par le percentile 90 de la Chl-a) a pu être calculé à partir des données satellite pour la quasi-totalité des masses d’eau côtières RCS et non RCS, c’est-à-dire 34 masses d’eau sur 39. Pour les cinq masses d’eau restantes, les limites liées à... |
| Tipo: Text |
Palavras-chave: Images satellite; Indice Biomasse; Directive Cadre sur l’eau; Chlorophylle a; Bassin Loire Bretagne; Qualité des masses d’eau; Indicateur Phytoplancton. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00453/56465/58162.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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| Perrot, Laurie; Gohin, Francis; Ruiz-pino, Diana; Lampert, Luis; Huret, Martin; Dessier, Aurelie; Malestroit, Pascale; Dupuy, Christine; Bourriau, Paul. |
| Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Ocean colour; Suspended particulate matter; Turbidity; Coccoliths; Stratification. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00416/52790/53689.pdf |
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| Lecornu, Fabrice; Pineau-guillou, Lucia; Dumas, Franck; Le Traon, Pierre-yves; Gohin, Francis; Menesguen, Alain. |
| Our coastal zones are subject to increasing anthropogenic pressure. Monitoring systems are required to protect them, prevent or mitigate risks and to ensure a sustainable management of their resources. PREVIMER is a partnership between Ifremer (French Research Institute for Exploitation of the Sea), SHOM (French Hydrographic Office) and several major French institutions (www.previmer.org). It provides coastal observations, analyses and 4 days forecasts for the French coasts of the English Channel, Atlantic Ocean and Mediterranean Sea: currents, water levels, waves, temperature, salinity, turbidity, nutrients and plankton concentrations. The service includes information based on in situ, satellite observations and numerical simulations. PREVIMER products... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00189/30039/28525.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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| Gohin, Francis; Lampert, Luis; Guillaud, Jean-francois; Herbland, Alain; Nezan, Elisabeth. |
| A phytoplankton bloom was observed in late winter 2000, on the continental shelf offshore of southern Brittany, in northwestern Bay of Biscay. This bloom appeared initially along the 120-m isobath, in stratified and clear waters, at the interface between the oceanic water and the plumes of southern Brittany rivers (mainly the Loire and Vilaine). The development of the bloom was triggered by favourable meteorological conditions, characterised by solar irradiance reaching the maximum level expected for that period of the year. Outside of the bloom area, the phytoplankton photosynthesis was irradiance limited: inshore, because of the stronger attenuation of the light; offshore, because of the weak stratification. The hydrological conditions at the onset of... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Coscinodiscus; Algal bloom; Phytoplankton; Ocean colour; Satellite sensing. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-463.pdf |
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| Lunven, Michel; Guillaud, Jean-francois; Crassous, Marie Pierre; Youenou, Agnes; Gohin, Francis; Huret, Martin; Danielou, Marie-madeleine; Kerouel, Roger; Labry, Claire; Aminot, Alain. |
| Inscrite dans le cadre du Grand Défi Golfe de Gascogne, la campagne VILOIR a été réalisée du 19 au 26 Juin 2003 à bord du Côtes de la Manche avec pour objectif l’étude en période estivale des structures hydrologiques et phytoplanctoniques des panaches de la Loire et de la Vilaine. Elle fait suite, sur la même thématique, à la campagne hivernale NUTRIGAS (2001) et à la campagne printanière GASPROD (2002). |
| Tipo: Text |
Palavras-chave: Surveillance; Littoral; Phytoplancton; Phycotoxines; Bretagne; Pays de Loire. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00144/25494/23648.pdf |
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| Lazure, Pascal; Huret, Martin; Gohin, Francis; Menesguen, Alain; Lecornu, Fabrice; Le Traon, Pierre-yves; Thomin, Pascale; Jegou, P.; Baraer, F.; Corre, Gilles; Louazel, Stephanie; Equipe projet PREVIMER. |
| Sommaire * Météo et débits des fleuves.....2 * Caractéristiques des masses d’eau côtières..............5 * Production biologique............11 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15 |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00242/35367/33866.pdf |
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| Registros recuperados: 76 | |
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