{
  "abstract": "Methane (CH ₄ ) is the second most important well-mixed greenhouse gas after carbon dioxide (CO ₂ ) and its accurate monitoring supports China's “dual carbon” goals. Satellites enable global CH ₄ monitoring using various sensors and retrieval techniques. The XCO ₂ proxy method derives the column-averaged dry-air mole fraction of CH ₄ (XCH ₄ ) from the XCH4/XCO2 ratio and an independent XCO ₂ estimate, exploiting the overlapping absorption bands of CH ₄ and CO ₂ near 1.6 µm and assuming similar vertical distributions to reduce common retrieval errors. In this study, four XCO ₂ proxy methane products, GOSAT SRPR, OCPR, FOCAL Proxy, and GOSAT-2 SRPR, are evaluated using Total Carbon Column Observing Network (TCCON) ground-based observations at the Hefei and Xianghe sites in China. GOSAT products show lower bias and RMSE at Xianghe than at Hefei, while GOSAT-2 products are similar at both sites, with lower bias, RMSE, and standard deviation compared with the GOSAT products and approximately 51 % of retrievals meeting GCOS requirements. All products, except OCPR, overestimate XCH ₄ at Hefei and underestimate XCH ₄ at Xianghe, due to XCO ₂ model errors and spatial differences associated with regional and local methane emissions affecting both sites. Furthermore, the overestimation of the ratio implies that the fundamental assumption of the XCO ₂ proxy method is not fulfilled, primarily due to systematic positive biases in the satellite-retrieved XCH ₄ used in the proxy calculation. This study provides key error characteristics and spatial-seasonal biases in current satellite proxy methane products over China, supporting future retrieval optimization.",
  "abstract_shown": true,
  "affiliations": [
    "Aerospace Information Research Institute (Beijing, China)"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "name": "Xinran Jiang",
      "orcid": "0009-0008-8609-244X"
    },
    {
      "name": "Gerrit de Leeuw",
      "orcid": "0000-0002-1649-6333"
    },
    {
      "affs": [
        0
      ],
      "name": "Cheng Fan",
      "orcid": "0000-0003-1547-9758"
    },
    {
      "name": "Jeon-Teo Dong",
      "orcid": "0000-0002-9877-3743"
    },
    {
      "name": "Andrew Gerald Barr",
      "orcid": "0000-0003-4909-2770"
    },
    {
      "name": "Wei Wang"
    },
    {
      "name": "Minqiang Zhou",
      "orcid": "0000-0003-3427-5873"
    },
    {
      "name": "Zhengqiang Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/baq89qhejhn8h.bib",
  "cited_by": 0,
  "doi": "10.5194/acp-26-15223-2026",
  "fulltext_url": null,
  "id": "baq89qhejhn8h",
  "issns": [
    "1680-7324"
  ],
  "landing_url": "https://doi.org/10.5194/acp-26-15223-2026",
  "language": null,
  "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": [
    [
      "feed-journal",
      "earth/atmospheric"
    ]
  ],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-29",
  "publisher": "Copernicus GmbH",
  "ris": "https://research.draconitic.com/paper/baq89qhejhn8h.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:16Z",
      "native_id": "10.5194/acp-26-15223-2026",
      "source": "feed-copernicus",
      "url": "https://doi.org/10.5194/acp-26-15223-2026"
    },
    {
      "first_seen": "2026-10-30T12:20:34Z",
      "native_id": "10.5194/acp-26-15223-2026",
      "source": "crossref",
      "url": "https://acp.copernicus.org/articles/26/15223/2026/"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "feed-journal:earth/atmospheric",
      "subfield": "atmospheric"
    }
  ],
  "title": "Evaluation of the GOSAT/GOSAT-2 XCO2 proxy XCH4 product by comparison with TCCON observations over China",
  "title_text": "Evaluation of the GOSAT/GOSAT-2 XCO2 proxy XCH4 product by comparison with TCCON observations over China",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T00:21:11Z",
  "url": "https://research.draconitic.com/paper/baq89qhejhn8h",
  "venue": "Atmospheric Chemistry and Physics",
  "versions": [
    {
      "doi": "10.5194/egusphere-2026-3382",
      "pid": null,
      "relation": "preprint",
      "title": null,
      "venue": null
    }
  ]
}