@prefix this: <https://w3id.org/sciencelive/np/RA9hvGhxFk1QOqFhSAUKzWbIyE0sdRduQgQOIzdVZvHJo> .
@prefix sub: <https://w3id.org/sciencelive/np/RA9hvGhxFk1QOqFhSAUKzWbIyE0sdRduQgQOIzdVZvHJo/> .
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@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix prov: <http://www.w3.org/ns/prov#> .
@prefix npx: <http://purl.org/nanopub/x/> .
@prefix dc: <http://purl.org/dc/terms/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

sub:Head {
  this: a np:Nanopublication;
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sub:assertion {
  <https://w3id.org/np/RAmR-xqMgOq3oTJmOVDQFL2p5usID6zqRapizHy0UJb04/concept> dc:description
      "The methodological choice of HEALPix geometry — perfect-sphere versus WGS84-ellipsoid — when resampling lat/lon-gridded SST observations to a HEALPix cell tessellation, prior to applying scattering-transform synthesis. The two geometries differ in how lat/lon points are  binned to cells." .
  
  <https://w3id.org/np/RAmR-xqMgOq3oTJmOVDQFL2p5usID6zqRapizHy0UJb04/context> dc:description
      "FOSCAT scattering-transform gap-filling pipelines for satellite-derived SST imagery, run at HEALPix resolutions ranging from coarse (nside=32, ~6° angular) to operational (nside=128, ~0.5° angular). The gap-filling task is to reconstruct cloud-obscured SST values using  the L4 gap-free product as a statistical reference, evaluating the result via RMSE against L4 in cloudy pixels." .
  
  <https://w3id.org/np/RAmR-xqMgOq3oTJmOVDQFL2p5usID6zqRapizHy0UJb04/population> dc:description
      "Daily Copernicus Marine sea surface temperature observations over the global ocean — specifically the L3S Passive Microwave product (cmems_obs-sst_glo_phy_l3s_pmw_P1D-m, with cloud gaps) and the L4 gap-free analysis (cmems_obs-sst_glo_phy-temp_nrt_P1D-m) used as ground truth, both at 0.25° native resolution. The 'population' here is the set of ocean pixels in a single day's observation." .
  
  sub:wgs84-vs-sphere-sst-gap-filling a <https://w3id.org/sciencelive/o/terms/PccReviewQuestion>;
    dc:description "Standard HEALPix-based scattering-transform gap-filling of satellite sea surface temperature observations assumes a perfect-sphere Earth model. The Earth is in fact an oblate ellipsoid better described by WGS84 — the same geometry used by GPS and operational geospatial  systems. This research question asks whether using WGS84 geometry rather than a sphere when binning lat/lon SST observations to HEALPix  cells measurably improves the accuracy of FOSCAT scattering-transform gap-filling, and whether any such improvement scales with HEALPix  resolution. The question matters operationally: SST gap-filling pipelines run at the highest resolution data is available, and any  systematic geometry-induced bias would compound with resolution.";
    <http://www.w3.org/2000/01/rdf-schema#label> "Does WGS84 ellipsoid geometry improve scattering-transform SST gap-filling vs the spherical assumption?";
    <https://w3id.org/sciencelive/o/terms/hasPccConcept> <https://w3id.org/np/RAmR-xqMgOq3oTJmOVDQFL2p5usID6zqRapizHy0UJb04/concept>;
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}

sub:provenance {
  sub:assertion prov:wasAttributedTo <https://orcid.org/0000-0002-1784-2920> .
}

sub:pubinfo {
  <https://orcid.org/0000-0002-1784-2920> <http://xmlns.com/foaf/0.1/name> "Anne Fouilloux" .
  
  this: dc:created "2026-04-26T18:22:17.292Z"^^xsd:dateTime;
    dc:creator <https://orcid.org/0000-0002-1784-2920>;
    dc:license <https://creativecommons.org/licenses/by/4.0/>;
    npx:introduces sub:wgs84-vs-sphere-sst-gap-filling;
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