Inherent optical properties and satellite retrieval of chlorophyll concentration in the lagoon and open ocean waters of New Caledonia

Dupouy, Cécile; Neveux, Jacques; Ouillon, Sylvain; Frouin, Robert; Murakami, Hiroshi; Hochard, Sébastien; Dirberg, Guillaume

doi:10.1016/j.marpolbul.2010.06.039

Cited by 44 publications

(69 citation statements)

References 64 publications

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“…Higher b bp (443) values (~0.0058 m −1 ) were also observed at the northern sector of the lagoon at CALIOPE 2, probably favoured by re-suspension processes in the shallowest areas. For both campaigns, the southern sector had the clearest waters with the lowest b bp (443) (~0.004 m −1 ), resembling clearer waters of the lagoons located in southwest New Caledonia [40][41][42], with greater influence of oceanic oligotrophic waters. The mean b bp spectral slope (S bbp ) was 0.07 ± 0.1 nm −1 , which is small compared to the values typically obtained in open ocean waters (between 1 and~3) [25] and likely associated with dominance of larger organic and inorganic particles.…”

Section: Environmental and Bio-optical Characterizationmentioning

confidence: 96%

“…The collection and processing of the bio-optical data are the same as described in Dupouy et al, [9,[40][41][42]. Vertical profiles of the backscattering coefficient (b b , m −1 ) were measured using a Hydroscat-6 (HobiLabs) scatterometer calibrated 1 month before the cruise, with 10 nm bands centred at 442, 488, 510, 550 nm, and 20 nm bands at 620 and 670 nm.…”

Section: Biogeochemical and Bio-optical Propertiesmentioning

confidence: 99%

“…The filters were stored in liquid nitrogen for laboratory analysis. The Chla was determined by two methods: (i) using an adapted fluorometric method after 90% methanol extraction, and subtracting for pheopigments after acidification [9,[40][41][42], and (ii) by High Performance Liquid Chromatography (HPLC) [55] (analysed by Crystal Thomas, NASA laboratory). The mean percent difference between the two measurements was lower than 10% indicating good accuracy.…”

Section: Biogeochemical and Bio-optical Propertiesmentioning

confidence: 99%

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Bio-Optical Characterization and Ocean Colour Inversion in the Eastern Lagoon of New Caledonia, South Tropical Pacific

et al. 2018

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Abstract:The Eastern Lagoon of New Caledonia (ELNC) is a semi-enclosed system surrounded by an extensive coral reef barrier. The system has been suffering impacts from climate variability and anthropogenic activities, including mining exploitation. Satellite monitoring is thus an essential tool to detect such changes. The present study aimed to assess the bio-optical variability of the ELNC and examine the applicability of ocean colour algorithms, using in situ bio-optical and radiometric data, collected during the March 2014 CALIOPE 2 cruise. The chlorophyll a concentration (Chla) varied from 0.13-0.72 mg·m −3 , and the coastal stations were spectrally dominated by non-algal particles (NAP) and coloured dissolved organic matter (CDOM) (>80% of the total non-water absorption at 443 nm), due to the contribution of allochthonous sources. The phytoplankton specific absorption was generally lower (mean, 0.049 m 2 ·mg Chla −1 ) than typical values observed for the corresponding Chla range, as well as the spectral slopes of the absorption of CDOM plus NAP (a dg ) (mean, 0.016 nm −1 ) and of the particle backscattering coefficient (b bp ) (mean, 0.07 nm −1 ). The remote sensing reflectance obtained using two in-water approaches and modelled from Inherent Optical Properties (IOPs) showed less than 20% relative percent differences (RPD). Chla estimates were highly biased for the empirical (OC4 and OC3) and semi-analytical (GSM, QAA, GIOP, LMI) algorithms, especially at the coastal stations. Excluding these stations, the GSM01 yielded the best retrievals with 35-40% RPD. a dg (443) was well retrieved by all algorithms with~18% RPD, and b bp (443) with~40% RPD. Turbidity algorithms also performed reasonably well (30% RPD), showing the capacity and usefulness of the derived products to monitor the water quality of the ELNC, provided accurate atmospheric correction of the satellite data. Regionally tuned algorithms may potentially improve the Chla retrievals, but better parameterization schemes that consider the spatiotemporal variability of the specific IOPs are still needed.

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Section: Environmental and Bio-optical Characterizationmentioning

confidence: 96%

Section: Biogeochemical and Bio-optical Propertiesmentioning

confidence: 99%

Section: Biogeochemical and Bio-optical Propertiesmentioning

confidence: 99%

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Bio-Optical Characterization and Ocean Colour Inversion in the Eastern Lagoon of New Caledonia, South Tropical Pacific

et al. 2018

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“…Each database contains in situ and MODIS R rs values in several spectral bands centered on 412 nm, 443 nm, 488 nm, 531 nm, 555 nm, and 667 nm for NCDataBase [29,31,38] and 547 instead of 555 nm for SeaBASS [40,41]. All MODIS R rs over New Caledonia in the NCDataBase were extracted from 2002 to 2010 [42].…”

Section: Datamentioning

confidence: 99%

“…When the two databases are merged, which we call Full DataBase (FDB), it is assumed that the 547 and 555 nm spectral bands give an equivalent signal, i.e., they are considered one category [20]. The NCDataBase contains bathymetry (in meters) and in situ [chl-a] (µg¨L´1) measured by fluorometry and spectrofluorometry [29,43]. Water samples were collected from a Niskin bottle at 2 m depth.…”

Section: Datamentioning

confidence: 99%

A Statistical Algorithm for Estimating Chlorophyll Concentration in the New Caledonian Lagoon

et al. 2016

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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]. The log-linear model is developed based on SVM regression analysis. This approach outperforms the classical OC3 approach, especially in shallow waters, with a root mean squared error 30% lower. The proposed algorithm enables more accurate assessments of [chl-a] and its variability in this typical oligo-to meso-trophic tropical lagoon, from shallow coastal waters and nearby reefs to deeper waters and in the open ocean.

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Colored and Chromophoric Dissolved Organic Matter in Natural Waters

Mostofa

Liu

Vione

et al. 2012

Environmental Science and Engineering

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Inherent optical properties and satellite retrieval of chlorophyll concentration in the lagoon and open ocean waters of New Caledonia

Cited by 44 publications

References 64 publications

Bio-Optical Characterization and Ocean Colour Inversion in the Eastern Lagoon of New Caledonia, South Tropical Pacific

Bio-Optical Characterization and Ocean Colour Inversion in the Eastern Lagoon of New Caledonia, South Tropical Pacific

A Statistical Algorithm for Estimating Chlorophyll Concentration in the New Caledonian Lagoon

Colored and Chromophoric Dissolved Organic Matter in Natural Waters

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