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| Registros recuperados: 10 | |
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| Bittig, Henry C.; Maurer, Tanya L.; Plant, Joshua N.; Schmechtig, Catherine; Wong, Annie P. S.; Claustre, Hervé; Trull, Thomas W.; Udaya Bhaskar, T. V. S.; Boss, Emmanuel; Dall’olmo, Giorgio; Organelli, Emanuele; Poteau, Antoine; Johnson, Kenneth S.; Hanstein, Craig; Leymarie, Edouard; Le Reste, Serge; Riser, Stephen C.; Rupan, A. Rick; Taillandier, Vincent; Thierry, Virginie; Xing, Xiaogang. |
| The Biogeochemical-Argo program (BGC-Argo) is a new profiling-float-based, ocean wide, and distributed ocean monitoring program which is tightly linked to, and has benefited significantly from, the Argo program. The community has recommended for BGC-Argo to measure six additional properties in addition to pressure, temperature and salinity measured by Argo, to include oxygen, pH, nitrate, downwelling light, chlorophyll fluorescence and the optical backscattering coefficient. The purpose of this addition is to enable the monitoring of ocean biogeochemistry and health, and in particular, monitor major processes such as ocean deoxygenation, acidification and warming and their effect on phytoplankton, the main source of energy of marine ecosystems. Here we... |
| Tipo: Text |
Palavras-chave: Ocean observation; Ocean biogeochemical cycles; Sensors; Carbon cycle; Ocean optics; Best practices; Argo. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62344/66607.pdf |
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| Barbieux, Marie; Uitz, Julia; Bricaud, Annick; Organelli, Emanuele; Poteau, Antoine; Schmechtig, Catherine; Gentili, Bernard; Obolensky, Grigor; Leymarie, Edouard; Penkerc'H, Christophe; D'Ortenzio, Fabrizio; Claustre, Herve. |
| Characterizing phytoplankton distribution and dynamics in the world's open oceans requires in situ observations over a broad range of space and time scales. In addition to temperature/salinity measurements, Biogeochemical-Argo (BGC-Argo) profiling floats are capable of autonomously observing at high-frequency bio-optical properties such as the chlorophyll fluorescence, a proxy of the chlorophyll a concentration (Chla), the particulate backscattering coefficient (b(bp)), a proxy of the stock of particulate organic carbon, and the light available for photosynthesis. We analyzed an unprecedented BGC-Argo database of more than 8,500 multivariable profiles collected in various oceanic conditions, from subpolar waters to subtropical gyres. Our objective is to... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00673/78495/80780.pdf |
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| Organelli, Emanuele; Claustre, Herve; Bricaud, Annick; Barbieux, Marie; Uitz, Julia; D'Ortenzio, Fabrizio; Dall'Olmo, Giorgio. |
| Identification of oceanic regions characterized by particular optical properties is extremely important for ocean color applications. The departure from globally established bio-optical models introduces uncertainties in the retrieval of biogeochemical quantities from satellite observations. Thanks to an array of 105 Biogeochemical Argo floats acquiring almost daily downward irradiance measurements at selected wavelengths in the UV and blue region of the spectrum, we re-examined the natural variability of the spectral diffuse attenuation coefficients, Kd(λ), among the world's oceans and compared them to previously established bio-optical models. The analysis of 2847 measurements of Kd(λ) at 380 and 490 nm, within the first optical depth, provided a... |
| Tipo: Text |
Palavras-chave: Bio-optical anomalies; Light attenuation; Biogeochemical Argo floats; Global ocean; Colored dissolved organic matter. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00383/49463/49948.pdf |
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| Xing, Xiaogang; Claustre, Herve; Boss, Emmanuel; Roesler, Collin; Organelli, Emanuele; Poteau, Antoine; Barbieux, Marie; D'Ortenzio, Fabrizio. |
| In situ chlorophyll fluorometers have been widely employed for more than half a century, and to date, it still remains the most used instrument to estimate chlorophyll-a concentration in the field, especially for measurements onboard autonomous observation platforms, e.g., Bio-Argo floats and gliders. However, in deep waters (> 300 m) of some specific regions, e.g., subtropical gyres and the Black Sea, the chlorophyll fluorescence profiles frequently reveal "deep sea red fluorescence" features. In line with previous studies and through the analysis of a large data set (cruise transect in the South East Pacific and data acquired by 82 Bio-Argo floats), we show that the fluorescence signal measured by a humic-like DOM fluorometer is highly correlated to... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77327/78783.pdf |
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| Organelli, Emanuele; Bricaud, Annick; Antoine, David; Uitz, Julia. |
| Models based on the multivariate partial least squares (PLS) regression technique are developed for the retrieval of phytoplankton size structure from measured light absorption spectra (BOUSSOLE site, northwestern Mediterranean Sea). PLS-models trained with data from the Mediterranean Sea showed good accuracy in retrieving, over the nine-year BOUSSOLE time series, the concentrations of total chlorophyll a [Tchl a], of the sum of seven diagnostic pigments and of pigments associated with micro, nano, and picophytoplankton size classes separately. PLS-models trained using either total particle or phytoplankton absorption spectra performed similarly, and both reproduced seasonal variations of biomass and size classes derived by high performance liquid... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00185/29655/28031.pdf |
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| Schmechtig, Catherine; Organelli, Emanuele; Poteau, Antoine; Claustre, Hervé; D'Ortenzio, Fabrizio. |
| In the open ocean, Colored Dissolved Organic Matter (CDOM) is the fraction of the total Dissolved Organic Matter (DOM), composed by a mixture of chemically complex algal degradation products that interact with light. CDOM absorbs solar radiation in the UV and visible ranges (Bricaud et al., 1981) and, if illuminated, re-emits light as fluorescence (i.e., FDOM; Coble 1996). These optical measurements can be used as proxies of CDOM concentration. Whereas CDOM absorption measurements are given by the entire pool of the organic matter, FDOM measurements detect only sub-fractions. Depending on excitation and emission wavelengths of the fluorometer, FDOM can represent the fresh-material produced by microbial degradation of phytoplankton cells and/or from... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00434/54541/55910.pdf |
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| Roesler, Collin; Uitz, Julia; Claustre, Herve; Boss, Emmanuel; Xing, Xiaogang; Organelli, Emanuele; Briggs, Nathan; Bricaud, Annick; Schmechtig, Catherine; Poteau, Antoine; D'Ortenzio, Fabrizio; Ras, Josephine; Drapeau, Susan; Haentjens, Nils; Barbieux, Marie. |
| Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relationship between in situ fluorescence and extracted Chl a concentration. Despite this large natural variability, we present here a global validation data set for the WET Labs Environmental Characterization Optics (ECO) series chlorophyll fluorometers that suggests a factor of 2 overestimation in the factory calibrated Chl a estimates for this specific manufacturer and series of sensors. We base these results on... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00384/49552/50046.pdf |
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| Pitarch, Jaime; Bellacicco, Marco; Organelli, Emanuele; Volpe, Gianluca; Colella, Simone; Vellucci, Vincenzo; Marullo, Salvatore. |
| Particulate optical backscattering (bbp) is a crucial parameter for the study of ocean biology and oceanic carbon estimations. In this work, bbp retrieval, by the quasi-analytical algorithm (QAA), is assessed using a large in situ database of matched bbp and remote-sensing reflectance (Rrs). The QAA is also applied to satellite Rrs (ESA OC-CCI project) as well, after their validation against in situ Rrs. Additionally, the effect of Raman Scattering on QAA retrievals is studied. Results show negligible biases above random noise when QAA-derived bbp is compared to in situ bbp. In addition, Rrs from the CCI archive shows good agreement with in situ data. The QAA’s functional form of spectral backscattering slope, as derived from in situ radiometry, is... |
| Tipo: Text |
Palavras-chave: Particulate optical backscattering; Raman scattering; QAA algorithm; ESA OC-CCI. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71889/70588.pdf |
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| Organelli, Emanuele; Barbieux, Marie; Claustre, Herve; Schmechtig, Catherine; Poteau, Antoine; Bricaud, Annick; Boss, Emmanuel; Briggs, Nathan; Dall'Olmo, Giorgio; D'Ortenzio, Fabrizio; Leymarie, Edouard; Mangin, Antoine; Obolensky, Grigor; Penkerc'H, Christophe; Prieur, Louis; Roesler, Collin; Serra, Romain; Uitz, Julia; Xing, Xiaogang. |
| Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is quality-assessed to identify issues... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00662/77389/79010.pdf |
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| Registros recuperados: 10 | |
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