Consulta: subjectFacets:"Ocean color"
Registros recuperados: 19
Data/hora: 13/06/2024 08:03:18

MULTISPECTRAL TRACKING OF PHYTOPLANKTON IN THE COLOMBIAN CARIBBEAN
Provedor de dados: 72
Autores: Ojeda Caicedo,V. V.; Plata Gómez,A.
In a quantitative research study, the concentration and circulation of group of micro-organisms "phytoplankton" have been found trough the images of the ocean colour in the Colombian Caribbean Sea. These images have been observed trough the Sea Star satellite. The method logical procedure was to collect a number of ocean images at the 1A level of the sensor SeaWifs. This only covered the geographical area of study and the seasons of the year. The selection criterion was to give priority to the absence of clouds in the area. Afterwards, the images were analyzed to create mosaics in convenient periods of the to, in turn visualize the periodical changes of the micro-organisms. Thus place with higher concentration of phytoplankton in the study site were...
Tipo: Journal article
Palavras-chave: Ocean color; Primary production; SeaWifs; SeaDas.
Ano: 2004
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000300024

ANALYSIS OF SPACE-TIME VARIABILITY OF THE PLATA RIVER PLUME
Provedor de dados: 72
Autores: Piola,Alberto R.; Romero,Silvia I.
Satellite ocean colour data from the Sea-Viewing Wide Field-of-View Sensor are analyzed to monitor the space-time variability of the Plata river plume over the continental shelf and slope. SeaWiFS Chlorophyll-a (CSAT) product is used to understand the nature of changes in the colour of waters and how this relates to variations in wind direction and river outflow. We use a 5-year data set (1998-2002) of Global Area Coverage monthly mean composites. The analysis of CSAT data reveals strong seasonal variability over the continental shelf with maximum northeastward penetrations in the austral winter (June to August). The plume may reach ~27S, about 1000 km northeast of the Plata estuary. In summer the plume is confined to south of 32&amp;deg;S and the Plata...
Tipo: Journal article
Palavras-chave: Ocean color; River plumes; Plata plume; SeaWiFS.
Ano: 2004
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000300030

Rain-derived particles and CDOM distribution along the East Coast of New Caledonia
Provedor de dados: 5
Autores: Dupouy, Cecile; Wattelez, Guillaume; Lefevre, Jerome; Juillot, Farid; Andreoli, Remi; Lille, Didier; Murakami, Hiroshi; Roettgers, Rudiger; Frouin, Robert.
Shortly after strong rains or tropical storms, chlorophyll-a concentration (Chla), turbidity, and colored dissolved organic matter (CDOM) in the lagoon of New Caledonia may be tripled. This effect is visible as far as 50 km offshore. The Eastern Coast of New Caledonia is more impacted than the Western Coast because of its geomorphological structure. Higher frequency and intensity of the rains, and the dominance of highly erosive lateritic formations resulted from deep weathering of ultramafic rocks. At the deeper parts of the lagoon (&gt; 20 m), increases of Chla, turbidity, and CDOM absorption can be detected by satellite imagery with their plumes extending off shore as a result of wind-driven circulation in the lagoon. Such -increases agree with the...
Tipo: Text
Palavras-chave: Minerals; Phytoplankton; CDOM; FDOM; Ocean color; Reflectance; New Caledonia; Tropical Pacific Ocean; Lagoons.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00481/59308/62064.pdf

Apports des données de la 'couleur de l'eau' à la modélisation couplée physique-biogéochimie en milieu dynamique côtier : Application au Rio de la Plata et au Golfe de Gascogne
Provedor de dados: 5
Autores: Huret, Martin.
Continental margins play a crucial role in biogeochemical fluxes between the continents and the open ocean. They are also highly sensitive to human perturbations. Primary production is highly dependent on the complex dynamics of these coastal zones, and on the river supply in nutrients, as well as in Suspended Particulate Matter (SPM) which limit light availability. The quantification of the production is a prerequisite in many applications, from the understanding of the role of the coastal ocean in climate change, to eutrophication and fisheries resources issues within the frame of the integrated management of the coastal zone.  Coupled physical-biogeochemical models are useful in studying and monitoring primary production. Because of the numerous complex...
Tipo: Text
Palavras-chave: Parameter estimation; Data assimilation; Suspended Particulate Matter (SPM); Chlorophyll a; Phytoplankton blooms; Physical biogeochemical coupled model; Ocean color; Satellite data; Coastal area; Bay of Biscay; Rio de la Plata; Estimation de paramètres; Assimilation de données; Matières En Suspension (MES); Chlorophylle a; Blooms phytoplanctoniques; Modèle couplé physique biogéochimie; Couleur de l'eau; Donnée satellitale; Milieu côtier; Golfe de Gascogne; Rio de la Plata.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/these-337.pdf

Fusion of Sun-Synchronous and Geostationary Images for Coastal and Ocean Color Survey Application to OLCI (Sentinel-3) and FCI (MTG)
Provedor de dados: 5
Autores: Peschoud, Cecile; Minghelli, Audrey; Mathieu, Sandrine; Lei, Manchun; Pairaud, Ivane; Pinazo, Christel.
Open ocean and coastal area monitoring requires multispectral satellite images with a middle spatial resolution ({\sim !300 {text{m}}}) and a high temporal repeatability ({\sim !1 {text{h}}}) . As no current satellite sensors have such features, the aim of this study is to propose a fusion method to merge images delivered by a low earth orbit (LEO) sensor with images delivered by a geostationary earth orbit (GEO) sensor. This fusion method, called spatial spectral temporal fusion (SSTF), is applied to the future sensors—Ocean and Land Color Instrument (OLCI) (on Sentinel-3) and Flexible Combined Imager (FCI) (on Meteosat Third Generation) whose images were simulated. The OLCI bands, acquired at t _{0} , are divided by the oversampled corresponding FCI band...
Tipo: Text
Palavras-chave: Fusion; Image simulation; Meteosat Third Generation (MTG); Ocean color; Ocean and Land Color Instrument.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00343/45413/49041.pdf

Regional Empirical Algorithms for an Improved Identification of Phytoplankton Functional Types and Size Classes in the Mediterranean Sea Using Satellite Data
Provedor de dados: 5
Autores: Di Cicco, Annalisa; Sammartino, Michela; Marullo, Salvatore; Santoleri, Rosalia.
Regional relationships to estimate the main Phytoplankton Functional Types (PFTs) and Size Classes (PSCs) from satellite data are presented. Following the abundance-based approach and selecting the Total Chlorophyll a (TChla) as descriptor of the trophic status of the environment, empirical relations between the TChla concentration and seven accessory pigments, marker for the main algal groups, have been developed for the Mediterranean Sea. Using only in-situ data acquired in this basin, firstly a previous regional diagnostic pigment analysis has been conducted to evaluate the specific pigment ratios featuring the phytoplankton assemblage that occurs in the Mediterranean Sea. Secondly, the new regional PFT and PSC algorithms have been calibrated and...
Tipo: Text
Palavras-chave: PFTs; PSCs; Mediterranean Sea; Regional algorithms; Ocean color.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00468/57983/60372.pdf

A Statistical Algorithm for Estimating Chlorophyll Concentration in the New Caledonian Lagoon
Provedor de dados: 5
Autores: Wattelez, Guillaume; Dupouy, Cecile; Mangeas, Morgan; Lefevre, Jerome; Touraivane,; Frouin, Robert.
Spatial and temporal dynamics of phytoplankton biomass and water turbidity can provide crucial information about the function, health and vulnerability of lagoon ecosystems (coral reefs, sea grasses, etc.). A statistical algorithm is proposed to estimate chlorophyll-a concentration ([chl-a]) in optically complex waters of the New Caledonian lagoon from MODIS-derived remote-sensing reflectance (R-rs). The algorithm is developed via supervised learning on match-ups gathered from 2002 to 2010. The best performance is obtained by combining two models, selected according to the ratio of R-rs in spectral bands centered on 488 and 555 nm: a log-linear model for low [chl-a] (AFLC) and a support vector machine (SVM) model or a classic model (OC3) for high [chl-a]....
Tipo: Text
Palavras-chave: Chlorophyll-a concentration; MODerate resolution Imaging Spectroradiometer (MODIS); Ocean color; Remote sensing; Statistical algorithm; Oligotrophic waters; New Caledonia; Coral lagoon.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00481/59309/62060.pdf

Development of a Semi-Analytical Algorithm for the Retrieval of Suspended Particulate Matter from Remote Sensing over Clear to Very Turbid Waters
Provedor de dados: 5
Autores: Han, Bing; Loisel, Hubert; Vantrepotte, Vincent; Meriaux, Xavier; Bryere, Philippe; Ouillon, Sylvain; Dessailly, David; Xing, Qianguo; Zhu, Jianhua.
Remote sensing of suspended particulate matter, SPM, from space has long been used to assess its spatio-temporal variability in various coastal areas. The associated algorithms were generally site specific or developed over a relatively narrow range of concentration, which make them inappropriate for global applications (or at least over broad SPM range). In the frame of the GlobCoast project, a large in situ data set of SPM and remote sensing reflectance, R-rs(lambda), has been built gathering together measurements from various coastal areas around Europe, French Guiana, North Canada, Vietnam, and China. This data set covers various contrasting coastal environments diversely affected by different biogeochemical and physical processes such as sediment...
Tipo: Text
Palavras-chave: Specific backscattering coefficient; Empirical algorithm; Semi-analytic algorithm; Coastal waters; Suspended particulate matter; Ocean color.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00589/70062/68010.pdf

Natural variability of bio-optical properties in Case 1 waters: attenuation and reflectance within the visible and near-UV spectral domains, as observed in South Pacific and Mediterranean waters
Provedor de dados: 5
Autores: Morel, A.; Claustre, H.; Antoine, D.; Gentili, B.
The optical properties of Case 1 waters have been empirically related to the chlorophyll concentration, [Chl], historically used as an index of the trophic state and of the abundance of the biological materials. The well-known natural variability around the mean statistical relationships is here examined by comparing the apparent optical properties (spectral downward irradiance attenuation and reflectance) as a function of [Chl] in two Case 1 environments, the Pacific and Mediterranean waters. These oceanic zones apparently represent two extremes of the possible bio-optical variability range around the mean. The systematic deviations, in both directions with respect to the average laws, mainly result from the differing contents in non-algal detrital...
Tipo: Text
Palavras-chave: Light absorption; Algal biomass; Ocean color; Chlorophyll; Sea; Phytoplankton; Model; Coefficients; Algorithms.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00209/32012/30549.pdf

Satellite-derived parameters for biological modelling in coastal waters: Illustration over the eastern continental shelf of the Bay of Biscay
Provedor de dados: 5
Autores: Gohin, Francis; Loyer, S; Lunven, Michel; Labry, Claire; Froidefond, J; Delmas, Daniel; Huret, Martin; Herbland, Alain.
In biological modelling of the coastal phytoplankton dynamics, the light attenuation coefficient is often expressed as a function of the concentrations of chlorophyll and mineral suspended particulate matter (SPM). In order to estimate the relationship between these parameters over the continental shelf of the northern Bay of Biscay, a set of in situ data has been gathered for the period 1998-2003 when SeaWiFS imagery is available. These data comprise surface measurements of the concentrations of total SPM, chlorophyll, and irradiance profiles from which is derived the attenuation coefficient of the photosynthetically available radiation, K-PAR. The performance of the IFREMER look-up table used to retrieve the chlorophyll concentration from the SeaWiFS...
Tipo: Text
Palavras-chave: Bay of Biscay; SeaWiFS; Sediment; Chlorophyll; Ocean color.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-1172.pdf

Decadal reanalysis of biogeochemical indicators and fluxes in the North West European shelf-sea ecosystem
Provedor de dados: 5
Autores: Ciavatta, S.; Kay, S.; Saux-picart, S.; Butenschon, M.; Allen, J. I.
This paper presents the first decadal reanalysis simulation of the biogeochemistry of the North West European shelf, along with a full evaluation of its skill, confidence, and value. An error-characterized satellite product for chlorophyll was assimilated into a physical-biogeochemical model of the North East Atlantic, applying a localized Ensemble Kalman filter. The results showed that the reanalysis improved the model simulation of assimilated chlorophyll in 60% of the study region. Model validation metrics showed that the reanalysis had skill in matching a large data set of in situ observations for 10 ecosystem variables. Spearman rank correlations were significant and higher than 0.7 for physical-chemical variables (temperature, salinity, and oxygen),...
Tipo: Text
Palavras-chave: Marine ecosystems; Data assimilation; Ocean color; Air-sea flux of carbon dioxide; Dissolved oxygen; Marine policy.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00383/49422/49850.pdf

Geostationary Image Simulation on Coastal Waters Using Hydrodynamic Biogeochemical and Sedimentary Coupled Models
Provedor de dados: 5
Autores: Lei, Manchun; Minghelli, Audrey; Fraysse, Marion; Pairaud, Ivane; Verney, Romaric; Pinazo, Christel.
This study proposes a method to simulate the images of the future European geostationary sensor dedicated to ocean color sensor: the geostationary ocean color advanced permanent imager (GeoOCAPI), and it demonstrates the sensor capabilities to monitor the water composition throughout the day. The temporal variation of the coastal seascape is obtained from biogeochemical and hydrosedimentary models, the ocean-atmosphere radiance is obtained from the water and atmosphere radiative transfer model. The GeoOCAPI images are simulated with 400-m resolution, 18 spectral bands with associated signal-to-noise ratio (SNR) and with 1-h acquisition frequency, on the Gulf of Lion (Marseille, France) during a pollution event caused by the urban outfall of Cortiou in...
Tipo: Text
Palavras-chave: Geostationary ocean color advanced permanent imager (GeoOCAPI); Geostationary orbit; Image simulation; Ocean color.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00363/47462/50154.pdf

Neural Network Approaches to Reconstruct Phytoplankton Time-Series in the Global Ocean
Provedor de dados: 5
Autores: Martinez, Elodie; Brini, Anouar; Gorgues, Thomas; Drumetz, Lucas; Roussillon, Joana; Tandeo, Pierre; Maze, Guillaume; Fablet, Ronan.
Phytoplankton plays a key role in the carbon cycle and supports the oceanic food web. While its seasonal and interannual cycles are rather well characterized owing to the modern satellite ocean color era, its longer time variability remains largely unknown due to the short time-period covered by observations on a global scale. With the aim of reconstructing this longer-term phytoplankton variability, a support vector regression (SVR) approach was recently considered to derive surface Chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) from physical oceanic model outputs and atmospheric reanalysis. However, those early efforts relied on one particular algorithm, putting aside the question of whether different algorithms may have specific...
Tipo: Text
Palavras-chave: Phytoplankton time-series reconstruction; Ocean color; Neural networks; Support vector regression; Multi-layer perceptron; Physical predictors.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00667/77871/80017.pdf

Biogeochemical Argo: The Test Case of the NAOS Mediterranean Array
Provedor de dados: 5
Autores: D’ortenzio, Fabrizio; Taillandier, Vincent; Claustre, Hervé; Prieur, Louis Marie; Leymarie, Edouard; Mignot, Alexandre; Poteau, Antoine; Penkerc’h, Christophe; Schmechtig, Catherine Marie.
The necessity of wide, global-scale observing systems for marine biogeochemistry emerged dramatically in the last decade. A global network based on Biogeochemical (BGC) Argo floats is considered to be one of the most promising approaches for reaching this goal. As a first step, pilot studies were encouraged to test the feasibility of a global BGC-Argo array, to consolidate the methods and practices under development, and to set up the array’s characteristics. A pilot study in The Mediterranean Sea—deemed a suitable candidate for a test case because it combines a relatively large diversity of oceanic BGC conditions in a reduced open-ocean basin—was consequently approved as a part of the “Novel Argo ocean Observing System” (NAOS) project, a French national...
Tipo: Text
Palavras-chave: BGC-Argo floats; Mediterranean; Bioregions; Ocean color; Physical biological interactions.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00618/73031/72145.pdf

Estimation of the diffuse attenuation coefficient K-dPAR using MERIS and application to seabed habitat mapping
Provedor de dados: 5
Autores: Saulquin, Bertrand; Hamdi, Anouar; Gohin, Francis; Populus, Jacques; Mangin, Antoine; D'Andon, Odile Fanton.
The availability of light in the water column and at the seabed determines the euphotic zone and constrains the type and the vertical distribution of algae species. Light attenuation is traditionally quantified as the diffuse attenuation coefficient of the downwelling spectral irradiance atwavelength 490 nm(Kd490) or the photosynthetically available radiation (KdPAR). Satellite observations provide global coverage of these parameters at high spatial and temporal resolution and several empirical and semi-analytical models are commonly used to derive Kd490 and KdPAR maps from ocean colour satellite sensors. Most of these existing empirical or semi-analytical models have been calibrated in open ocean waters and performwell in these regions, but tend to...
Tipo: Text
Palavras-chave: Ocean color; Light attenuation; Photosynthetic available radiation; Euphotic depth; Seabed mapping.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00117/22831/21496.pdf

Optical algorithms at satellite wavelengths for Total Suspended Matter in tropical coastal waters
Provedor de dados: 5
Autores: Ouillon, Sylvain; Douillet, Pascal; Petrenko, Anne; Neveux, Jacques; Dupouy, Cecile; Froidefond, Jean-marie; Andrefouet, Serge; Munoz-caravaca, Alain.
Is it possible to derive accurately Total Suspended Matter concentration or its proxy, turbidity, from remote sensing data in tropical coastal lagoon waters? To investigate this question, hyperspectral remote sensing reflectance, turbidity and chlorophyll pigment concentration were measured in three coral reef lagoons. The three sites enabled us to get data over very diverse environments: oligotrophic and sediment-poor waters in the southwest lagoon of New Caledonia, eutrophic waters in the Cienfuegos Bay (Cuba), and sediment-rich waters in the Laucala Bay (Fiji). In this paper, optical algorithms for turbidity are presented per site based on 113 stations in New Caledonia, 24 stations in Cuba and 56 stations in Fiji. Empirical algorithms are tested at...
Tipo: Text
Palavras-chave: Ocean color; Remote sensing; Sediment transport; Suspended matter; Turbidity; New Caledonia; Cuba; Fiji.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00203/31417/29808.pdf

Effect of seafloor depth on phytoplankton blooms in high-nitrate, low-chlorophyll (HNLC) regions
Provedor de dados: 5
Autores: Tyrrell, T.; Merico, A.; Waniek, J. J.; Wong, C. S.; Metzl, N.; Whitney, F.
We calculated correlations between seafloor depth and phytoplankton blooms in all three main high-nitrate, low-chlorophyll (HNLC) regions, but with a particular focus on the subarctic North Pacific area. It has long been known that the central parts of the east and west subarctic North Pacific are HNLC regions. The deep western basin of the Bering Sea is also HNLC, whereas the wide continental shelf of the eastern Bering Sea is not. We carried out a statistical comparison of spatial maps of (1) seafloor depth and (2) chlorophyll a concentration from satellite data. This comparison reveals that shallow waters have, on average, higher peak chlorophyll a concentrations (more intense phytoplankton blooms) than deep waters (p &lt;&lt; 0.01). Possible artifacts...
Tipo: Text
Palavras-chave: Phytoplankton; Ocean color; Bathymetry; HNLC; North Pacific; Iron.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00232/34337/32758.pdf

ProVal: A New Autonomous Profiling Float for High Quality Radiometric Measurements
Provedor de dados: 5
Autores: Leymarie, Edouard; Penkerc'H, Christophe; Vellucci, Vincenzo; Lerebourg, Christophe; Antoine, David; Boss, Emmanuel; Lewis, Marion R.; D'Ortenzio, Fabrizio; Claustre, Herve.
An efficient system to produce in situ high quality radiometric measurements is compulsory to rigorously perform the vicarious calibration of satellite sensors dedicated to Ocean Color Radiometry (OCR) and to validate their derived products. This requirement is especially needed during the early stages of an OCR satellite activity or for remote areas poorly covered by oceanographic cruises with possible bio-optical anomalies. Taking advantage of Argo's profiling float technology, we present a new autonomous profiling float dedicated to in situ radiometric measurements. The float is based on the Provor CTS5 (manufacturer NKE) with an added novel two protruding arm design allowing for sensor redundancies, shading mitigation and near-surface data. Equipped...
Tipo: Text
Palavras-chave: Autonomous profiling floats; Remote sensing reflectance; Ocean color; Validation; System vicarious calibration; Austral ocean; Mediterranean Sea; Radiometric measurement.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00585/69694/67579.pdf

Comparison of spaceborne measurements of sea surface salinity and colored detrital matter in the Amazon plume
Provedor de dados: 5
Autores: Fournier, Severine; Chapron, Bertrand; Salisbury, J.; Vandemark, Douglas; Reul, Nicolas.
Large rivers are key hydrologic components in oceanography, particularly regarding air-sea and land-sea exchanges and biogeochemistry. We enter now in a new era of Sea Surface Salinity (SSS) observing system from Space with the recent launches of the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius/Sac-D missions. With these new sensors, we are now in an excellent position to revisit SSS and ocean color investigations in the tropical northwest Atlantic using multi-year remote sensing time series and concurrent in situ observations. The Amazon is the world's largest river in terms of discharge. In its plume, SSS and upper water column optical properties such as the absorption coefficient of colored detrital matter (acdm) are strongly...
Tipo: Text
Palavras-chave: Amazon-Orinoco river plume; SMOS SSS; Conservative mixing; Ocean color; Salinity; Satellite oceanography.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00255/36610/35742.pdf