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| Registros recuperados: 15 | |
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| Białek, Agnieszka; Goodman, Teresa; Woolliams, Emma; Brachmann, Johannes F. S.; Schwarzmaier, Thomas; Kuusk, Joel; Ansko, Ilmar; Vabson, Viktor; Lau, Ian C.; Maclellan, Christopher; Marty, Sabine; Ondrusek, Michael; Servantes, William; Taylor, Sarah; Van Dommelen, Ronnie; Barnard, Andrew; Vellucci, Vincenzo; Banks, Andrew C.; Fox, Nigel; Vendt, Riho; Donlon, Craig; Casal, Tânia. |
| We present the results from Verification of Reference Irradiance and Radiance Sources Laboratory Calibration Experiment Campaign. Ten international laboratories took part in the measurements. The spectral irradiance comparison included the measurements of the 1000 W tungsten halogen filament lamps in the spectral range of 350 nm–900 nm in the pilot laboratory. The radiance comparison took a form of round robin where each participant in turn received two transfer radiometers and did the radiance calibration in their own laboratory. The transfer radiometers have seven spectral bands covering the wavelength range from 400 nm–700 nm. The irradiance comparison results showed an agreement between all lamps within ±1.5%. The radiance comparison results presented... |
| Tipo: Text |
Palavras-chave: Ocean colour; Spectral irradiance comparison; Spectral radiance sources comparison; Fiducial reference measurements. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00655/76688/77827.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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| 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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| 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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| Lavigne, H.; Van Der Zande, D.; Ruddick, K.; Cardoso Dos Santos, J.f.; Gohin, Francis; Brotas, V.; Kratzer, S.. |
| Reliable satellite estimates of chlorophyll-a concentration (Chl-a) are needed in coastal waters for applications such as eutrophication monitoring. However, because of the optical complexity of coastal waters, retrieving accurate Chl-a is still challenging. Many algorithms exist and give quite different performance for different optical conditions but there is no clear definition of the limits of applicability of each algorithm and no clear basis for deciding which algorithm to apply to any given image pixel (reflectance spectrum). Poor quality satellite Chl-a data can easily reach end-users. To remedy this and provide a clear decision on when a specific Chl-a algorithm can be used, we propose simple quality control tests, based on MERIS water leaving... |
| Tipo: Text |
Palavras-chave: Ocean colour; Chlorophyll-a algorithms; Coastal waters; Quality control; Algorithm-switching approach; MERIS; OLCI; Sentinel-3. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00675/78758/80933.pdf |
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| Martinez, Elodie; Raapoto, Hirohiti; Maes, Christophe; Maamaatuaihutapu, Keitapu. |
| The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the... |
| Tipo: Text |
Palavras-chave: Tropical instability waves; La Nina; Chlorophyll-a concentration variability; Ocean colour; Island mass effect; Marquesas islands; Oceanography; Satellite observations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54858/56346.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: 15 | |
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