Multi-sensor satellite time series of optical properties and chlorophyll-a concentration in the Adriatic Sea

Mélin, Frédéric; Vantrepotte, Vincent; Clerici, M.; D’Alimonte, Davide; Zibordi, Giuseppe; Berthon, Jean-François; Canuti, Elisabetta

doi:10.1016/j.pocean.2010.12.001

Cited by 90 publications

(69 citation statements)

References 77 publications

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“…The link between abiotic factors and phytoplankton variability, in the Mediterranean Sea, has been mainly inferred by using satellite ocean color data (Antoine et al, 1995;Bosc et al, 2004;Mélin et al, 2011;Volpe et al, 2012). Based on band-ratio algorithms that infer surface chlorophyll a concentration (considered as a proxy of phy-toplankton biomass), a general picture of the Mediterranean was revealed, confirming and reinforcing what had been derived by the relatively scarce existing in situ estimations, e.g., the presence of a widespread oligotrophy, of strong east-west and north-south gradients, the coastal influences, and the occurrence of blooming episodes in well-defined regions.…”

Section: Introductionmentioning

confidence: 99%

Interannual variability of the Mediterranean trophic regimes from ocean color satellites

et al. 2016

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Abstract. D'Ortenzio and Ribera d'Alcalà (2009, DR09hereafter) divided the Mediterranean Sea into "bioregions" based on the climatological seasonality (phenology) of phytoplankton. Here we investigate the interannual variability of this bioregionalization. Using 16 years of available ocean color observations (i.e., SeaWiFS and MODIS), we analyzed the spatial distribution of the DR09 trophic regimes on an annual basis. Additionally, we identified new trophic regimes, exhibiting seasonal cycles of phytoplankton biomass different from the DR09 climatological description and named "Anomalous". Overall, the classification of the Mediterranean phytoplankton phenology proposed by DR09 (i.e., "No Bloom", "Intermittently", "Bloom" and "Coastal"), is confirmed to be representative of most of the Mediterranean phytoplankton phenologies. The mean spatial distribution of these trophic regimes (i.e., bioregions) over the 16 years studied is also similar to the one proposed by DR09, although some annual variations were observed at regional scale. Discrepancies with the DR09 study were related to interannual variability in the sub-basin forcing: winter deep convection events, frontal instabilities, inflow of Atlantic or Black Sea Waters and river run-off. The large assortment of phytoplankton phenologies identified in the Mediterranean Sea is thus verified at the interannual scale, further supporting the "sentinel" role of this basin for detecting the impact of climate changes on the pelagic environment.

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Section: Introductionmentioning

confidence: 99%

Interannual variability of the Mediterranean trophic regimes from ocean color satellites

et al. 2016

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“…2016, 8,722 5 of 22 nadir but oblique, so the measurements on the ground are only partially representative of the nadir water reflectance from 300 m pixels as sensed by MERIS.…”

Section: Ground Truth Datasetmentioning

confidence: 99%

MOD2SEA: A Coupled Atmosphere-Hydro-Optical Model for the Retrieval of Chlorophyll-a from Remote Sensing Observations in Complex Turbid Waters

et al. 2016

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An accurate estimation of the chlorophyll-a (Chla) concentration is crucial for water quality monitoring and is highly desired by various government agencies and environmental groups. However, using satellite observations for Chla estimation remains problematic over coastal waters due to their optical complexity and the critical atmospheric correction. In this study, we coupled an atmospheric and a water optical model for the simultaneous atmospheric correction and retrieval of Chla in the complex waters of the Wadden Sea. This coupled model called MOD2SEA combines simulations from the MODerate resolution atmospheric TRANsmission model (MODTRAN) and the two-stream radiative transfer hydro-optical model 2SeaColor. The accuracy of the coupled MOD2SEA model was validated using a matchup data set of MERIS (MEdium Resolution Imaging SpectRometer) observations and four years of concurrent ground truth measurements (2007)(2008)(2009)(2010) at the NIOZ jetty location in the Dutch part of the Wadden Sea. The results showed that MERIS-derived Chla from MOD2SEA explained the variations of measured Chla with a determination coefficient of R 2 = 0.88 and a RMSE of 3.32 mg·m −3 , which means a significant improvement in comparison with the standard MERIS Case 2 regional (C2R) processor. The proposed coupled model might be used to generate a time series of reliable Chla maps, which is of profound importance for the assessment of causes and consequences of long-term phenological changes of Chla in the turbid Wadden Sea area.

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“…A novelty detection scheme Bishop, 1994) was used to verify the algorithm applicability range by evaluating the representativeness of the input data in the training dataset (D'Alimonte et al, 2003;Mélin et al, 2011;Sá et al, 2015). The adopted applicability range is based on a novelty index (η) presented in published works (D'Alimonte et al, 2013;Sá et al, 2015).…”

Section: Regional Mlp Nn Algorithmmentioning

confidence: 99%

Technical note: Algal Pigment Index 2 in the Atlantic off the southwest Iberian Peninsula: standard and regional algorithms

et al. 2016

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Abstract. In this study, Algal Pigment Index 2 (API2) is investigated in Sagres, an area located in the Atlantic off the southwestern Iberian Peninsula. Standard results provided by the MEdium Resolution Image Spectrometer (MERIS) ocean colour sensor were compared with alternative data products, determined through a regional inversion scheme, using both MERIS and in situ remote sensing reflectances (R rs ) as input data. The reference quantity for performance assessment is in situ total chlorophyll a (TChl a) concentration estimated through a phytoplankton absorption coefficient (i.e. equivalent to API2). Additional comparison of data products has also been addressed for TChl a concentration determined by high-performance liquid chromatography. The MERIS matchup analysis revealed a systematic underestimation of TChl a, which was confirmed with an independent comparison of product map analysis. The study demonstrates the importance of regional algorithms for the study area that could complement upcoming standard results of the current Sentinel-3/OLCI space mission. IntroductionThe MEdium Resolution Image Spectrometer (MERIS) space sensor, operated by the European Space Agency (ESA) on-board the ENVISAT platform from 2002 to 2012, has been continuously supported by investigations for the assessment and improvement of data products. Commissioned studies include the validation of radiometric data such as the R rs Kajiyama et al., 2014), as well as the analyses of derived product maps D'Alimonte et al., 2014;Cristina et al., 2016b). These MERIS validation activities have established an important basis to address Earth observation (EO) capabilities through the Ocean Land Colour Instrument (OLCI) sensor launched on the Sentinel-3 satellite in February 2016. OLCI data products are the main component of the Copernicus European programme to monitor the marine environment, and the retrieval of chlorophyll a (Chl a) is a core task of the Sentinel-3 space mission. Chl a is needed to estimate the phytoplankton biomass in the ocean and to contribute to a variety of interrelated investigations and applications, including climate data records, environmental legislation, and a number of economic activities such as fisheries and aquaculture. After the removal of the atmospheric contribution to the signal recorded at the top of the atmosphere, Chl a can be estimated from the bottom-of-atmosphere (BOA) R rs values, using the standard approach with polynomial algorithms based on band ratios of the input radiometric quantities. The corresponding MERIS data product is denoted Algal Pigment Index 1 (API1) (Morel and Antoine, 2011). The use of band ratio is based on the assumption that seawater optical properties are driven by Chl a. A tendency towards overestimation has, however, been documented in optically complex marine conditions . This can occur when optically active constituents, such as coloured dissolved orPublished by Copernicus Publications on behalf of the European Geosciences Union.

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Multi-sensor satellite time series of optical properties and chlorophyll-a concentration in the Adriatic Sea

Cited by 90 publications

References 77 publications

Interannual variability of the Mediterranean trophic regimes from ocean color satellites

Interannual variability of the Mediterranean trophic regimes from ocean color satellites

MOD2SEA: A Coupled Atmosphere-Hydro-Optical Model for the Retrieval of Chlorophyll-a from Remote Sensing Observations in Complex Turbid Waters

Technical note: Algal Pigment Index 2 in the Atlantic off the southwest Iberian Peninsula: standard and regional algorithms

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