[ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/assertion", "@graph": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/sentinel2-parameter-asymmetry-open-source-westerschelde", "http://purl.org/dc/terms/subject": [ { "@id": "http://www.wikidata.org/entity/Q133878" }, { "@id": "http://www.wikidata.org/entity/Q199687" }, { "@id": "http://www.wikidata.org/entity/Q4302480" }, { "@id": "http://www.wikidata.org/entity/Q47053" }, { "@id": "http://www.wikidata.org/entity/Q625376" }, { "@id": "http://www.wikidata.org/entity/Q898574" } ], "http://purl.org/spar/cito/isSupportedBy": [ { "@id": "https://w3id.org/sciencelive/np/RAGe9U1qrzbrHI6bZjkM7d3vuwbAkv5j1K0S5cEC8HYkk" }, { "@id": "https://w3id.org/sciencelive/np/RAoh82dxkJvR73OU_ttKf2_mtwgXY5_8qgcp3S7tmhcVM" } ], "http://schema.org/endDate": [ { "@value": "2026-07-25", "@type": "http://www.w3.org/2001/XMLSchema#date" } ], "@type": [ "https://w3id.org/sciencelive/o/terms/Research-Synthesis" ], "http://www.w3.org/2000/01/rdf-schema#label": [ { "@value": "Open-source Sentinel-2 reproduces the parameter-dependent water-quality retrieval asymmetry in the Westerschelde" } ], "https://w3id.org/sciencelive/o/terms/hasConditionsDescription": [ { "@value": "This synthesis holds within the following scope:\n\n- Domain and site: a turbid, mesotidal, well-mixed temperate estuary — the Westerschelde\n (Netherlands). It generalises to comparable optically complex Case-2 estuaries, not to\n clear open-ocean (Case-1) water.\n- Processing chain: the fully open-source Acolite atmospheric correction with the Gons\n et al. (2005) red-edge algorithm for chlorophyll-a (aGS) and the Nechad et al. (2010)\n algorithm for turbidity (aN783). This is NOT the paper's proprietary C2RCC chain\n (cGS / cN783); the synthesis compares an open-source chain against the paper's\n proprietary result and does not re-run C2RCC.\n- Sensor and period: Sentinel-2 MSI (A/B/C era), imagery 2016–2026.\n- Reference: coincident Rijkswaterstaat in situ observations at along-axis stations;\n turbidity compared in linear space (FNU on both sides, no unit conversion),\n chlorophyll-a compared in log10 space, matching the paper's treatment of each.\n- Sample sizes: small — turbidity N = 11 match-ups, chlorophyll-a N = 33. The direction\n of each verdict is robust; precise magnitudes carry wide uncertainty.\n- Design: a Replication (different site, different period, open-source processor), not a\n Reproduction — the Sado in situ data are not public.\n- Out of scope: grid-sensitivity of the retrieval (a HEALPix / DGGS GRID4EARTH\n representation of the corrected fields) is deferred to a separate follow-up chain that\n will extend this one; the primary validation stays on the native Sentinel-2 grid." } ], "https://w3id.org/sciencelive/o/terms/hasLimitationsDescription": [ { "@value": "1. Not a head-to-head processor test. The paper's headline numbers (cGS R² = 0.63,\n cN783 R² = 0.84) are the proprietary C2RCC chain, which was never run here (C2RCC\n exists only inside ESA SNAP and crashes in the container). The synthesis compares an\n open-source chain against the paper's published proprietary result; it does not prove\n the open-source chain equals C2RCC on the same imagery. In particular, the finding\n that open-source Acolite matches C2RCC for turbidity is a single-site observation, not\n a general claim that Acolite outperforms C2RCC everywhere.\n\n2. Small samples. With N = 11 (turbidity) and N = 33 (chlorophyll-a), each R² carries a\n wide confidence interval. The composed asymmetry is qualitatively robust across the\n two limbs; the exact R² values should not be over-read.\n\n3. Single estuary, single reference network. Both limbs were validated in one\n Westerschelde record against one in situ provider. Whether the parameter-dependent\n asymmetry holds in structurally different estuaries, or against other reference\n networks, was not tested here.\n\n4. Retrieval bias not corrected. The turbidity retrieval carries a slight positive bias\n (+6.91 FNU) and the chlorophyll-a retrieval a positive bias with a negative slope;\n these are reported, not corrected, and would matter for any quantitative use.\n\n5. Grid representation untested. Any sensitivity of these verdicts to spatial\n re-gridding (HEALPix / DGGS) is explicitly out of scope and deferred to a follow-up\n chain." } ], "https://w3id.org/sciencelive/o/terms/hasRecommendationDescription": [ { "@value": "1. Do not treat \"Sentinel-2 water-quality retrieval\" as a single capability. Validate\n and report accuracy per parameter: a chain trustworthy for turbidity can be\n simultaneously unreliable for chlorophyll-a in the same water.\n\n2. For estuarine turbidity monitoring (e.g. Water Framework Directive reporting), a\n fully open-source Acolite + Nechad chain is a viable, citable alternative to the\n proprietary C2RCC processor — here it matched and slightly exceeded the proprietary\n result in a different estuary.\n\n3. For estuarine chlorophyll-a, treat MSI retrievals in turbid Case-2 water as\n provisional. The paper's call for \"a more complete set of match-ups\" stands; collect\n more coincident in situ pairs and validate locally before any operational use, and do\n not assume a red-edge algorithm is tracking pigment rather than backscatter.\n\n4. Prefer open-source, operationally reproducible processing chains for replication and\n monitoring: they make the retrieval auditable end-to-end and, on the turbidity limb\n here, cost nothing in accuracy." } ], "https://w3id.org/sciencelive/o/terms/hasSynthesisDescription": [ { "@value": "Sent et al. (2021) reported that Sentinel-2 MSI retrieves estuarine water-quality\nparameters with parameter-dependent accuracy — strong for turbidity, weak for\nchlorophyll-a. This synthesis composes two independent replication limbs and finds\nthat the asymmetry itself is what replicates. In an independent, more turbid estuary\n(the Westerschelde) and with a fully open-source atmospheric-correction chain\n(Acolite), the two parameters behave exactly as the paper's asymmetry predicts, but\nthey land on opposite verdicts. The turbidity limb CONFIRMS the paper: the open-source\nAcolite + Nechad (aN783) chain retrieves in situ turbidity in strong agreement,\nR² = 0.92 with a near-unity slope (0.86), meeting and slightly exceeding the paper's\nproprietary C2RCC + Nechad (cN783) result of R² = 0.84. The chlorophyll-a limb\nQUALIFIES the paper's own caution: the open-source Acolite + Gons (aGS) chain achieves\nno useful agreement with in situ chlorophyll-a, R² = 0.10 (log10 space), far below the\npaper's selected C2RCC + Gons (cGS) result of R² = 0.63, deepening rather than\nresolving the weakness the original authors flagged. The composed, replicated result\nis therefore not a single accuracy number but a structural property: Sentinel-2\nwater-quality retrieval accuracy is parameter-dependent, and that dependence survives\nboth a change of estuary and the replacement of the proprietary processor by an\nopen-source one." } ] } ] }, { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/Head", "@graph": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s", "http://www.nanopub.org/nschema#hasAssertion": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/assertion" } ], "http://www.nanopub.org/nschema#hasProvenance": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/provenance" } ], "http://www.nanopub.org/nschema#hasPublicationInfo": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/pubinfo" } ], "@type": [ "http://www.nanopub.org/nschema#Nanopublication" ] } ] }, { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/provenance", "@graph": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/assertion", "http://www.w3.org/ns/prov#wasAttributedTo": [ { "@id": "https://orcid.org/0000-0002-1784-2920" } ] } ] }, { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/pubinfo", "@graph": [ { "@id": "https://orcid.org/0000-0002-1784-2920", "http://xmlns.com/foaf/0.1/name": [ { "@value": "Anne Fouilloux" } ] }, { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s", "http://purl.org/dc/terms/created": [ { "@value": "2026-07-25T16:49:06.935Z", "@type": "http://www.w3.org/2001/XMLSchema#dateTime" } ], "http://purl.org/dc/terms/creator": [ { "@id": "https://orcid.org/0000-0002-1784-2920" } ], "http://purl.org/dc/terms/license": [ { "@id": "https://creativecommons.org/licenses/by/4.0/" } ], "http://purl.org/nanopub/x/introduces": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/sentinel2-parameter-asymmetry-open-source-westerschelde" } ], "http://purl.org/nanopub/x/wasCreatedAt": [ { "@id": "https://platform.sciencelive4all.org" } ], "http://www.w3.org/2000/01/rdf-schema#label": [ { "@value": "Open-source Sentinel-2 reproduces the parameter-dependent water-quality retrieval asymmetry in the Westerschelde" } ], "https://w3id.org/np/o/ntemplate/wasCreatedFromTemplate": [ { "@id": "https://w3id.org/np/RApmrqOEr4f5bJC2vayrTnzhwnuEfAU_I4Pdg8K5JxeBw" } ] }, { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s/sig", "http://purl.org/nanopub/x/hasAlgorithm": [ { "@value": "RSA" } ], "http://purl.org/nanopub/x/hasPublicKey": [ { "@value": "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" } ], "http://purl.org/nanopub/x/hasSignature": [ { "@value": "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" } ], "http://purl.org/nanopub/x/hasSignatureTarget": [ { "@id": "https://w3id.org/sciencelive/np/RAFOMMXsXiYG-lWxSyjomq6wkhjx4t_BLo01u7Buuif2s" } ], "http://purl.org/nanopub/x/signedBy": [ { "@id": "https://orcid.org/0000-0002-1784-2920" } ] } ] } ]