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| Registros recuperados: 16 | |
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| Paparazzo,Flavio E.; Alder,Viviana A.; Schloss,Irene R.; Bianchi,Alejandro; Esteves,Jose L.. |
| The Drake Passage (DP) links the Southern Pacific and Atlantic Oceans, and acts as a physical narrowing for the largest current of the World Ocean, the Antarctic Circumpolar Current (ACC). This result in a constriction of the main circumpolar fronts related to the ACC: the Subantarctic Front, the Polar Front, the Southern Antarctic Circumpolar Current Front and the Continental Water Boundary Front. Previous studies showed that the DP is a high-nutrient low-chlorophyll (HNLC) region, but studies on the interannual and seasonal macronutrients' fluctuations in relation with chlorophyll and frontal areas in the DP are scarce. This study analyzes the spatial and temporal trends of nitrate, phosphate, and silicate on surface samples from 113 oceanographic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrate; Phosphate; Silicate; Chlorophyll-a; Temperature; Salinity; Antarctic fronts; Antarctic zones; Seasonal variation; Interannual variation. |
| Ano: 2016 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1667-782X2016000100004 |
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| Vianello, Patrick; Ternon, Jean-francois; Demarcq, Herve; Herbette, Steven; Roberts, Michael J.. |
| This work is part of the MADRidge Project special issue which aims to describe pelagic ecosystems in the vicinity of three prominent shallow seamounts in the South West Indian Ocean: one here named MAD-Ridge (240 m below the surface) plus Walters Shoal (18 m) on the Madagascar Ridge, and La Pérouse (60 m) on the abyssal plain east of Madagascar. The three span latitudes 20°S and 33°S, some 1500 km. The study provides the background oceanography for the once-off, multidisciplinary snapshot cruise studies around the seamounts. As life on seamounts is determined by factors such as summit depth, proximity to the light layers of the ocean, and the ambient circulation, a first description of regional spatial-field climatologies (16–22 years) and monthly... |
| Tipo: Text |
Palavras-chave: South West Indian Ocean; Madagascar Ridge; Seamounts; Walters shoal; Sea surface temperature; Eddy kinetic energy; Mixed layer depth; Chlorophyll-a; Geostrophic currents. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74581/74476.pdf |
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| Lund-hansen, Lc; Vang, T. |
| Upwelling of cold. saline, and nutrient rich water was observed in late September 1999 along an east-west transect in the SW Kattegat. The Kattegat forms part of the transitional zone between the high saline North Sea and the low saline Baltic Sea. The upwelling occurred after an extended period of northward flow and eastern winds in the Kattegat, that changed into a southward flow as wind ceased. The upwelling was the result of a combination of high current speeds and bottom topography whereby the high-speed inflow water was forced towards the surface at the slope. Nutrient data show that the upwelling brought nutrient rich bottom water to the light exposed surface and a related strong (1943.5 ml(-1)) bloom of Pseudo-nitzschia pseudodelicatissima was... |
| Tipo: Text |
Palavras-chave: Courant; Upwelling; Front; Fluorescence; Chlorophylle-a; Inflow; Upwelling; Frontal structure; Fluorescence; Chlorophyll-a. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00321/43249/42980.pdf |
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| Soppa, Mariana A.; Hirata, Takafumi; Silva, Brenner; Dinter, Tilman; Peeken, Ilka; Wiegmann, Sonja; Bracher, Astrid. |
| Diatoms are the major marine primary producers on the global scale and, recently, several methods have been developed to retrieve their abundance or dominance from satellite remote sensing data. In this work, we highlight the importance of the Southern Ocean (SO) in developing a global algorithm for diatom using an Abundance Based Approach (ABA). A large global in situ data set of phytoplankton pigments was compiled, particularly with more samples collected in the SO. We revised the ABA to take account of the information on the penetration depth (Z(pd)) and to improve the relationship between diatoms and total chlorophyll-a (TChla). The results showed that there is a distinct relationship between diatoms and TChla in the SO, and a new global model... |
| Tipo: Text |
Palavras-chave: Ocean colour; Phytoplankton functional types; Diatom; Remote sensing; Chlorophyll-a. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40075/39289.pdf |
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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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| Gohin, Francis; Bryère, Philippe; Lefebvre, Alain; Sauriau, Pierre-guy; Savoye, Nicolas; Vantrepotte, Vincent; Bozec, Yann; Cariou, Thibault; Conan, Pascal; Coudray, Sylvain; Courtay, Gaelle; Françoise, Sylvaine; Goffart, Anne; Hernández Fariñas, Tania; Lemoine, Maud; Piraud, Aude; Raimbault, Patrick; Rétho, Michael. |
| The consistency of satellite and in situ time series of Chlorophyll-a (Chl-a), Turbidity and Total Suspended Matters (TSM) was investigated at 17 coastal stations throughout the year 2017. These stations covered different water types, from relatively clear waters in the Mediterranean Sea to moderately turbid regions in the Bay of Biscay and the southern bight of the North-Sea. Satellite retrievals were derived from MODIS/AQUA, VIIRS/NPP and OLCI-A/Sentinel-3 spectral reflectance. In situ data were obtained from the coastal phytoplankton networks SOMLIT (CNRS), REPHY (Ifremer) and associated networks. Satellite and in situ retrievals of the year 2017 were compared to the historical seasonal cycles and percentiles, 10 and 90, observed in situ. Regarding the... |
| Tipo: Text |
Palavras-chave: Satellite; Coastal monitoring; Chlorophyll-a; Total suspended matter; Turbidity. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00645/75669/76536.pdf |
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| Poisson Caillault, Emilie; Lefebvre, Alain. |
| Marine water quality monitoring and subsequent management require to know when a specific event like harmful algae bloom may occur and which environmental conditions and pressures lead to this event. So, event detection and its dynamic understanding are crucial to adapt strategy. An algorithm is proposed to identify curves mixture and their dynamics features - initiation, duration, peaks and ends of the event. The approach is fully unsupervised, it requires no tuning parameters and is based on Expectation Maximization process to estimate the most robust mixture according to fixed criteria. A complete framework is proposed to deal with a univariate time series with missing data. The approach is applied on Chlorophyll- a series collected weekly since 1989.... |
| Tipo: Text |
Palavras-chave: Time series; Event detection; Expectation-Maximisation; Phenology; Chlorophyll-a; Phaeocystis. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00435/54679/56097.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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| Sathyendranath, Shubha; Brewin, Robert; Brockmann, Carsten; Brotas, Vanda; Calton, Ben; Chuprin, Andrei; Cipollini, Paolo; Couto, André; Dingle, James; Doerffer, Roland; Donlon, Craig; Dowell, Mark; Farman, Alex; Grant, Mike; Groom, Steve; Horseman, Andrew; Jackson, Thomas; Krasemann, Hajo; Lavender, Samantha; Martinez-vicente, Victor; Mazeran, Constant; Mélin, Frédéric; Moore, Timothy; Müller, Dagmar; Regner, Peter; Roy, Shovonlal; Steele, Chris; Steinmetz, François; Swinton, John; Taberner, Malcolm; Thompson, Adam; Valente, André; Zühlke, Marco; Brando, Vittorio; Feng, Hui; Feldman, Gene; Franz, Bryan; Frouin, Robert; Gould, Richard; Hooker, Stanford; Kahru, Mati; Kratzer, Susanne; Mitchell, B.; Muller-karger, Frank; Sosik, Heidi; Voss, Kenneth; Werdell, Jeremy; Platt, Trevor. |
| Ocean colour is recognised as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS); and spectrally-resolved water-leaving radiances (or remote-sensing reflectances) in the visible domain, and chlorophyll-a concentration are identified as required ECV products. Time series of the products at the global scale and at high spatial resolution, derived from ocean-colour data, are key to studying the dynamics of phytoplankton at seasonal and inter-annual scales; their role in marine biogeochemistry; the global carbon cycle; the modulation of how phytoplankton distribute solar-induced heat in the upper layers of the ocean; and the response of the marine ecosystem to climate variability and change. However, generating a long time series... |
| Tipo: Text |
Palavras-chave: Ocean colour; Water-leaving radiance; Remote-sensing reflectance; Phytoplankton; Chlorophyll-a; Inherent optical properties; Climate Change Initiative; Optical water classes; Essential Climate Variable; Uncertainty characterisation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00589/70072/68045.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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| Registros recuperados: 16 | |
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