https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/Head https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://www.nanopub.org/nschema#hasAssertion https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/assertion https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://www.nanopub.org/nschema#hasProvenance https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/provenance https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://www.nanopub.org/nschema#hasPublicationInfo https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/pubinfo https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.nanopub.org/nschema#Nanopublication https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/assertion https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/sciencelive/o/terms/FORRT-Replication-Study https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/sciencelive/o/terms/Replication-Study https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2000/01/rdf-schema#label Open-source Sentinel-2 chlorophyll-a retrieval validated against in situ data in the Westerschelde estuary https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q133878 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q4302480 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q47053 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q4817104 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q625376 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/o/terms/hasDeviationDescription Five deliberate deviations, each recorded rather than hidden: 1. Atmospheric-correction processor. The paper selected C2RCC for its chlorophyll-a time series (the "cGS" chain, C2RCC + Gons). C2RCC exists only inside ESA SNAP and crashes natively in the container, so it is excluded; this replication runs Acolite instead, making the chain "aGS" (Acolite + Gons), an open-source analogue. Note the original study itself reports Acolite as its worst-performing processor. 2. Site. Validation is in the Westerschelde estuary, not the Sado, because the Sado in situ match-up data are available only on request (paper Data Availability Statement) and no open, contemporaneous, in-estuary substitute exists. The Westerschelde is a comparable mesotidal, well-mixed, turbid estuary. 3. Period. The record spans January 2016 to July 2026 (the full Sentinel-2 era), not the original's March 2018 to March 2020 field campaign, to gain the "more complete set of match-ups" the paper called for. 4. In situ reference. Coincident chlorophyll-a comes from Rijkswaterstaat routine monitoring stations, not the original AQUASado sampling campaign. 5. Fully open-source chain. Every step (Sentinel-2 L1C, Acolite, the Gons algorithm) is open and reproducible, whereas the original's selected chain depends on the proprietary SNAP/C2RCC processor. https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/o/terms/hasDiscipline http://www.wikidata.org/entity/Q199687 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/o/terms/hasMethodologyDescription The satellite half of the paper's pipeline is reproduced with a fully open-source chain (the "aGS" chain) and validated against an independent in situ reference. Sentinel-2 A/B/C Level-1C granules over the Westerschelde estuary are atmospherically corrected with Acolite to water-leaving reflectance, clipped to an estuary bounding box covering the along-axis stations. Chlorophyll-a is retrieved with the Gons et al. (2005) red-edge three-band algorithm, using the 665, 705 and 783 nm bands, transcribed from the original paper's Table 2; the bands are matched by nearest wavelength to absorb the Sentinel-2 A/B/C band-centre drift. At each in situ station a 3x3 pixel window is cut on the native 10 m UTM grid, with per-pixel quality control (water only, no cloud/shadow/glint, atmospheric-correction success), and the valid pixels are averaged. Satellite retrievals are paired with coincident in situ chlorophyll-a from Rijkswaterstaat monitoring stations on station and time within a plus-or-minus two-hour window. Agreement is scored with the paper's metric suite (coefficient of determination, slope, intercept, RMSE, bias, unbiased RMS, absolute and relative percentage difference), with the regression-family metrics computed in log10 space for chlorophyll-a and the percentage-difference metrics on untransformed values, exactly as the original specifies. Statistics are reported both over the full Sentinel-2 record and over the original study's field-campaign window, to separate the effect of changing the period from the effect of changing the site. https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/o/terms/hasScopeDescription This study tests only the chlorophyll-a limb of the original claim: the assertion that Sentinel-2 MSI retrieval of chlorophyll-a is the weak side of a parameter- dependent accuracy — that chlorophyll-a is the parameter for which further research and a more complete set of match-ups are still needed. In scope is whether an independent, satellite-derived chlorophyll-a product agrees with coincident in situ chlorophyll-a measurements in a mesotidal, well-mixed, turbid estuary, and whether the original study's weak-chlorophyll-a caution still holds when the retrieval chain is fully open source and transferred to a different estuary and a longer period. Out of scope, and left to separate atomic chains, are the turbidity, suspended- particulate-matter and coloured-dissolved-organic-matter limbs of the paper's asymmetry, the seasonal time-series analysis, and any grid-sensitivity (HEALPix / DGGS) representation of the corrected fields. https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/o/terms/targetsClaim https://w3id.org/sciencelive/np/RAuzyXFNXL_jqMA3b5isvsSW3W-LNjqGrMaeKdCW_VLWc https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/provenance https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/assertion http://www.w3.org/ns/prov#wasAttributedTo https://orcid.org/0000-0002-1784-2920 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/pubinfo https://orcid.org/0000-0002-1784-2920 http://xmlns.com/foaf/0.1/name Anne Fouilloux https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://purl.org/dc/terms/created 2026-07-25T16:23:23.490Z https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://purl.org/dc/terms/creator https://orcid.org/0000-0002-1784-2920 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://purl.org/dc/terms/license https://creativecommons.org/licenses/by/4.0/ https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://purl.org/nanopub/x/introduces https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/chla-open-source-westerschelde-replication https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://purl.org/nanopub/x/wasCreatedAt https://platform.sciencelive4all.org https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM http://www.w3.org/2000/01/rdf-schema#label Open-source Sentinel-2 chlorophyll-a retrieval validated against in situ data in the Westerschelde estuary https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM https://w3id.org/np/o/ntemplate/wasCreatedFromTemplate https://w3id.org/np/RAuLEjPp-4dTvPwMkfHggTto1CgjIftiGRAgHlyeEonjQ https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/sig http://purl.org/nanopub/x/hasAlgorithm RSA https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/sig http://purl.org/nanopub/x/hasPublicKey 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 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/sig http://purl.org/nanopub/x/hasSignature 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 https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/sig http://purl.org/nanopub/x/hasSignatureTarget https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM https://w3id.org/sciencelive/np/RAlQ4qJBnhxePAPzuL0Iy1mp4Ks61AAMfQCoP0kZ65ECM/sig http://purl.org/nanopub/x/signedBy https://orcid.org/0000-0002-1784-2920