{
  "abstract": "Data assimilation (DA) combines observations and model background to estimate the state of geophysical systems. Coherent structures, such as ocean eddies, are localized geophysical features characterized by a small set of properties: position, amplitude, and shape for instance. When linear and gaussian DA is applied directly to a gridded field without prior structural adjustment, the linear combination of background and observation can distort these properties, particularly when displacement uncertainty dominates. In this work, we explore a DA framework of coherent structures in a reduced parametric space, where the state is defined by a set of parameters describing the structure. Using an idealized one-dimensional ocean eddy, we compare single-step analyses performed both in gridded and parametric spaces. Three tutorial experiments with prescribed parametric uncertainties illustrate this distortion mechanism directly. A fourth experiment, starting from noisy gridded observations, provides a more balanced evaluation using the inverse nonlinear mapping from grid to parameter space. In these idealized experiments, the parametric approach maintains a physically consistent shape after assimilation. The parametric DA requires reliable parameter extraction, and its benefits depend on the number of structures relative to grid resolution.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "Solène Dealbera"
    },
    {
      "name": "Stéphane Raynaud"
    },
    {
      "name": "Carlos Granero Belinchon"
    },
    {
      "name": "Brahim Boussidi"
    },
    {
      "name": "Clément Le Goff"
    },
    {
      "name": "Pierre Tandeo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8sw9n1az95gc3.bib",
  "cited_by": 0,
  "doi": "10.5194/npg-33-489-2026",
  "fulltext_url": null,
  "id": "8sw9n1az95gc3",
  "issns": [
    "1023-5809",
    "1607-7946"
  ],
  "landing_url": "https://imt-atlantique.hal.science/hal-05759485v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.math"
    ],
    [
      "hal",
      "0.sdu"
    ],
    [
      "hal",
      "0.stat"
    ],
    [
      "hal",
      "1.math.math-st"
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    [
      "hal",
      "1.sdu.ocean"
    ],
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      "hal",
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    ],
    [
      "openalex",
      "1910|Oceanographic and Atmospheric Processes"
    ]
  ],
  "openalex": "W7213916928",
  "pdf_url": "https://imt-atlantique.hal.science/hal-05759485/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-21",
  "publisher": "European Geosciences Union (EGU)",
  "ris": "https://research.draconitic.com/paper/8sw9n1az95gc3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:37Z",
      "native_id": "hal-05759485",
      "source": "hal",
      "url": "https://imt-atlantique.hal.science/hal-05759485v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "hal:1.sdu.ocean",
      "subfield": "oceanography"
    },
    {
      "field": "mathematics",
      "origin": "hal:0.stat",
      "subfield": "statistics"
    }
  ],
  "title": "Data assimilation of coherent structures in parametric and gridded spaces: an idealized ocean eddy study",
  "title_text": "Data assimilation of coherent structures in parametric and gridded spaces: an idealized ocean eddy study",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:37Z",
  "url": "https://research.draconitic.com/paper/8sw9n1az95gc3",
  "venue": "Nonlinear Processes in Geophysics",
  "versions": []
}