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| Vantrepotte, Vincent; Danhiez, Francois-pierre; Loisel, Hubert; Ouillon, Sylvain; Meriaux, Xavier; Cauvin, Arnaud; Dessailly, David. |
| Increasing our knowledge on dissolved organic carbon (DOC) spatio-temporal distribution in the coastal ocean represents a crucial challenge for better understanding the role of these ecosystems in the global oceanic carbon cycle. The assessment of DOC concentration from the absorption properties of the colored part of the dissolved organic matter (a(cdom)) was investigated from an extensive data set covering a variety of coastal environments. Our results confirmed that variation in the acdom(412) to DOC ratio (a*(cdom)(412)) can be depicted from the CDOM spectral slope in the UV domain (S275-295). They also evidenced that regional first order variation in both a*(cdom)(412) and S275-295 are highly correlated to variation in acdom(412). From these... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00589/70063/68011.pdf |
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| Lubac, Bertrand; Loisel, Hubert; Guiselin, Natacha; Astoreca, Rosa; Artigas, L. Felipe; Meriaux, Xavier. |
| Identification of phytoplankton groups from space is essential to map and monitor algal blooms in coastal waters, but remains a challenge due to the presence of suspended sediments and dissolved organic matter which interfere with phytoplankton signal. On the basis of field measurements of remote sensing reflectance (Rrs(λ)), bio-optical parameters, and phytoplankton cells enumerations, we assess the feasibility of using multispectral and hyperspectral approaches for detecting spring blooms of Phaeocystis globosa (P. globosa). The two reflectance ratios (Rrs(490)/Rrs(510) and Rrs(442.5)/Rrs(490)), used in the multispectral inversion, suggest that detection of P. globosa blooms are possible from current ocean color sensors. The effects of chlorophyll... |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00240/35132/33636.pdf |
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| Loisel, Hubert; Meriaux, Xavier; Berthon, Jean-francois; Poteau, Antoine. |
| The variability of the backscattering to scattering ratio of marine particles, bbp: bp, is examined from in situ measurements performed during the spring and early summer of 2004 in the eastern English Channel and southern North Sea. This area is characterized by a quasi-permanent background of mineral matter from direct inputs, or resuspension effects, and by relatively intense spring phytoplankton blooms (mainly diatoms and the prymnesiophyte Phaeocystis globosa). The b(bp): b(p) surface values range between 0.0024 and 0.0417, with a mean value of 0.0138 +/- 0.0083. In order to interpret such a great variability, simultaneous water samples were collected for the biogeochernical characterization of the bulk suspended particle population. We show that the... |
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| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00240/35135/33637.pdf |
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| 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 |
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| Dinh Ngoc, Dat; Loisel, Hubert; Vantrepotte, Vincent; Chu Xuan, Huy; Nguyen Minh, Ngoc; Verpoorter, Charles; Meriaux, Xavier; Thi Minh, Hanh Pham; Le Thi, Huong; Le Vu Hong, Hai; Nguyen Van, Thao. |
| VNREDSat-1 is the first Vietnamese satellite enabling the survey of environmental parameters such as vegetation and water coverages, or surface water quality at medium spatial resolution (from 2.5 to 10 meters depending on the considered channel). The NAOMI sensor on board VNREDSat-1 has the required spectral bands to assess the suspended particulate matter concentration, SPM. Because recent studies have shown that the remote sensing reflectance, Rrs(ƒÜ), at the blue (450 ¡V 520 nm), green (530 ¡V 600 nm), and red (620 ¡V 690 nm) spectral bands can be assessed from NAOMI with a good accuracy, the present study is dedicated to the development and validation of an algorithm (hereafter referred to as V1SPM) to assess SPM from Rrs(ƒÜ) over inland and coastal... |
| Tipo: Text |
Palavras-chave: VNREDSat-1/NAOMI; Landsat-8/OLI; Suspended particulate matter; Algorithm. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00648/76043/76979.pdf |
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| Loisel, H.; Vantrepotte, V.; Norkvist, K.; Meriaux, Xavier; Kheireddine, M.; Ras, J.; Pujo-pay, M.; Combet, Y.; Leblanc, K.; Dall'Olmo, G.; Mauriac, R.; Dessailly, D.; Moutin, T.. |
| The variability of inherent optical properties is investigated in the ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM experiment performed during early summer 2008. Bio-optical relationships found for ultra-oligotrophic waters of the three anticyclonic gyres sampled significantly depart from the mean standard relationships provided for the global ocean, confirming the peculiar character of these Mediterranean waters. These optical anomalies are diversely related to the specific biological and environmental conditions occurring in the studied ecosystem. Specifically, the surface specific phytoplankton absorption coefficient exhibits values lower than those expected from the general relationships mainly in relation with a high... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24403/22415.pdf |
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