{
  "edition": "0.3.2",
  "prepared": "2026-10-22",
  "purpose": "What is known about what the ENSOFORECAST fields are and when they were made, claim by claim. 'status' uses only the declared vocabulary: VERIFIED_LOCALLY, DOCUMENTED, INFERRED, UNVERIFIED, UNKNOWN. 'scope' says what the evidence covers. Where a source documents something about a product but its correspondence to this archive's files is open, 'archive_mapping_status' records that separately, from the same vocabulary.",
  "entries": [
    {
      "id": "E1",
      "claim": "The nine documented core files and the transfer are byte-identical to what Aaron Kaplan sent.",
      "status": "VERIFIED_LOCALLY",
      "scope": "Integrity of Vultax's copy",
      "evidence": [
        "Transfer MD5 1e8b1b29f8e77697fbdbc90d3ca168ac matches the sender's checksum; SHA-256 ee0e93452bafaa08e64ade880c5b548d389d0653099be6e8b19de79e112037c7 recorded.",
        "validate.py --source-tgz re-hashes all nine core files and re-derives every time axis, mask and displayed slice."
      ],
      "limits": "Integrity of the copy, not of the original production."
    },
    {
      "id": "E2",
      "claim": "Each model field is a lag-average of forecasts from six consecutive monthly initial conditions, then corrected with singular value decomposition for systematic spatial errors.",
      "status": "DOCUMENTED",
      "scope": "IRI catalog description of ENSOFORECAST",
      "evidence": [
        {
          "source": "ENSOFORECAST catalog description (Steve Zebiak), second and third sentences from the end",
          "url": "https://github.com/iridl/dlentries/blob/master/descriptions/ensoforecasts.html",
          "paraphrase": "Forecast fields are composited by lag-averaging runs from six consecutive monthly initial conditions; the 3-, 6-, 9- and 12-month composites are then post-processed by SVD."
        }
      ],
      "limits": "The catalog does not say which six months relative to the nominal lead, nor the scaling applied after SVD."
    },
    {
      "id": "E3",
      "claim": "In LDEO's 1996–1997 bulletin articles, a nominal lead counts from the latest of the six initial conditions.",
      "status": "DOCUMENTED",
      "scope": "Forecast fields published in the Experimental Long-Lead Forecast Bulletin, 1996–1997",
      "archive_mapping_status": "UNVERIFIED",
      "evidence": [
        {
          "source": "Zebiak and Cane, Experimental Long-Lead Forecast Bulletin, September 1997, paragraph 2",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep97/art03.html",
          "paraphrase": "The 6-, 9- and 12-month fields verifying in January, April and July 1998 were averages of runs started in each month from February to July 1997."
        },
        {
          "source": "Same series, December 1997, paragraph 2",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec97/a12.html",
          "paraphrase": "The 6-, 9- and 12-month fields verifying in April, July and October 1998 averaged runs started from May to October 1997."
        }
      ],
      "limits": "Whether the archive's composites follow the same convention is not documented. If they do, a nominal 12-month field for December 1997 blends runs started July–December 1996. The bulletin figures were also rescaled on an overall basis, which may differ from the archive's post-processing."
    },
    {
      "id": "E4",
      "claim": "In the bulletins, 'LDEO2' names the improved-initialization version of the model (Chen et al. 1995), issued since the latter half of 1995, alongside the original version.",
      "status": "DOCUMENTED",
      "scope": "Bulletin naming of LDEO forecast versions",
      "archive_mapping_status": "UNVERIFIED",
      "evidence": [
        {
          "source": "Zebiak and Cane, December 1997 bulletin, paragraphs 1 and 5",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec97/a12.html",
          "paraphrase": "Forecasts from a version with improved initialization had been issued since the latter half of 1995; the article calls that system LDEO2 and compares it with the traditional Lamont forecast."
        },
        {
          "source": "Chen, Zebiak, Busalacchi and Cane (1995), Science 269:1699-1702",
          "url": "https://doi.org/10.1126/science.269.5231.1699"
        }
      ],
      "limits": "The archive's documentation does not define LDEO1 or LDEO2; the label match suggests, but does not establish, that the archive's LDEO2 files are the bulletin's improved system. The bulletins date public issuance, not production: even if the correspondence holds, a first documented issue in the latter half of 1995 does not show when experimental fields were first generated, so no archive field is classified as retrospective on this basis. The bulletin dates define labelled context phases only (EVALUATION-PROTOCOL.md). The retrospective classification of targets up to 1985-12, including the 1982 fields, rests separately on the model chronology (E5)."
    },
    {
      "id": "E5",
      "claim": "The 1982 model fields are retrospective (produced after the event).",
      "status": "INFERRED",
      "scope": "All model slices with target 1982-12, from the independent model chronology",
      "evidence": [
        {
          "source": "Cane and Lee (2013), p. 72",
          "url": "https://ocp.ldeo.columbia.edu/res/div/ocp/pub/cane/CaneLee.2013.pdf",
          "quote": "first predictions of the future, made in early 1986"
        }
      ],
      "limits": "Exact production date unknown. How fitting and evaluation were separated is not established; no finding of improper use of future information. The chronology supports the inference by target month, for targets up to 1985-12 only; a field started in late 1985 for a 1986 target could have been issued in real time, so later targets remain issue time unverified."
    },
    {
      "id": "E6",
      "claim": "In September 1997 the authors reported that both LDEO model versions were starting from eastern-Pacific SST anomalies well below those observed, and that the models had not handled the 1997 warm event as well as earlier events.",
      "status": "DOCUMENTED",
      "scope": "Contemporaneous statement by the modelers about their real-time forecasts",
      "archive_mapping_status": "UNVERIFIED",
      "evidence": [
        {
          "source": "Zebiak and Cane, September 1997 bulletin, paragraph 4 (final sentences)",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep97/art03.html",
          "paraphrase": "Both versions were initializing with eastern tropical Pacific anomalies far below the July observations; the authors were investigating why the models had handled this warm event less well than 1982-83 or 1986-87."
        }
      ],
      "limits": "Consistent with the weak 1997 warming in the archive's fields; it does not show that the archived fields are the ones the bulletin discussed or issued."
    },
    {
      "id": "E7",
      "claim": "The archive's December 1997 model fields are the fields issued at the time.",
      "status": "UNVERIFIED",
      "scope": "Issue timing of the archived 1997 fields",
      "candidate_receipts": [
        {
          "issue": "September 1996",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep96/art06.html"
        },
        {
          "issue": "December 1996",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec96/art06.html"
        },
        {
          "issue": "June 1997",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Jun97/q03.html"
        },
        {
          "issue": "September 1997",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep97/art03.html"
        },
        {
          "issue": "December 1997",
          "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec97/a12.html"
        }
      ],
      "proposed_test": "Decode the archive's LDEO1 and LDEO2 fields for the bulletins' own target months and leads (for example January, April and July 1998 at 6, 9 and 12 months from the September 1997 issue) and compare them with the published figures. Not yet done; the bulletin figures do not include December 1997 maps.",
      "limits": "Files carry no issue timestamps; reruns or reprocessing after issue cannot be excluded."
    },
    {
      "id": "E8",
      "claim": "Anomaly reference period of the observation and forecast fields.",
      "status": "UNKNOWN",
      "scope": "Anomaly baseline",
      "limits": "Not stated in the catalog or the file headers inspected."
    },
    {
      "id": "E9",
      "claim": "Identity and vintage of the observation product in data/ossta.cdf.",
      "status": "UNKNOWN",
      "scope": "Observation product",
      "limits": "The catalog says the model is initialized with FSU pseudo-stress winds; the observed SST source is not named in what we hold."
    },
    {
      "id": "E10",
      "claim": "The ENSOFORECAST dataset is not restricted.",
      "status": "DOCUMENTED",
      "scope": "IRI's restriction flag for the catalogued dataset",
      "evidence": [
        {
          "source": "IRI Data Library alternate-sources spreadsheet, row 59 (checked 22 October 2026)",
          "url": "https://docs.google.com/spreadsheets/d/1z-wPPicca67O_XLexFonC42cjY1z0Fy8ZoZirYLySNw/edit#range=A59:F59",
          "row_values": "Restricted: No; Current Source: IRI; DL Source: IRI"
        }
      ],
      "limits": "A restriction flag, not a named licence. It covers the catalogued dataset, not the 40 unidentified extra files in the transfer."
    },
    {
      "id": "E11",
      "claim": "One valid-cell mask, the same 1,077 cells, is shared by every target month of all nine core files.",
      "status": "VERIFIED_LOCALLY",
      "scope": "Spatial masks of the documented core",
      "evidence": [
        "Computed from the source transfer on 22 October 2026: exactly one distinct valid-cell set across all months of all nine files; recorded in coverage.json (indices SHA-256) and re-checked by validate.py --source-tgz."
      ],
      "limits": "A property of the files as transferred; says nothing about how the mask was chosen or about skill."
    }
  ],
  "retrieved_for_this_ledger": [
    {
      "url": "https://ocp.ldeo.columbia.edu/res/div/ocp/pub/cane/CaneLee.2013.pdf",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "daed68843ade1c5a90a9ccf75e8b81193a2f261ade0904b007d23fa71d1c6e11",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "CaneLee2013.pdf"
    },
    {
      "url": "https://raw.githubusercontent.com/iridl/dlentries/master/descriptions/ensoforecasts.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "fc20441cd65efdec17d4c7c37f4d8195d9523d8e201fe0654311319af9fb55ce",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "catalog-ensoforecasts.html"
    },
    {
      "url": "https://api.github.com/repos/iridl/dlentries/contents/entries/ENSOFORECAST",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "6ed80b7af476411c72b934c4a84f511bf268cf3ad790db7c3b26fa7e1e929f6a",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "catalog-entries-ENSOFORECAST.json"
    },
    {
      "url": "https://api.crossref.org/works/10.1126/science.269.5231.1699",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "3a2200293317f691e4930c43f59299a7e6146adfd4279639ccfeec7f484c2905",
      "unchanged_since_first_retrieval": null,
      "copy_held_privately_by_vultax": "crossref-chen-1995.json"
    },
    {
      "url": "https://api.crossref.org/works/10.1175/1520-0493(1987)115%3C2262:AMENO%3E2.0.CO;2",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "b5309eea96fd75e1e79619ef4059fd7af4f3416d2642dd36e5ec57affdd12cd2",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "crossref-zebiak-cane-1987.json"
    },
    {
      "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec96/art06.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "3205d31c6ccf59e6d5a9227e813354954c697e9a9bf85daf1dc9eefd90b0bdfe",
      "unchanged_since_first_retrieval": null,
      "copy_held_privately_by_vultax": "ellfb-Dec96_art06.html"
    },
    {
      "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Dec97/a12.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "e29e08284085e6941fe4c9959895ab515bf3cbd8a83593bd92f2278b53308cf7",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "ellfb-Dec97_a12.html"
    },
    {
      "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Jun97/q03.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "927f93a2d8b626895a698df209dd5fb599693de83f59b2ac6164a35e1b737916",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "ellfb-Jun97_q03.html"
    },
    {
      "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep96/art06.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "e352f4f682b0b6fbfe99a14d4903ea5e1b31310bbc1b6cd192c5ea4f98cd99c5",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "ellfb-Sep96_art06.html"
    },
    {
      "url": "https://www.cpc.ncep.noaa.gov/products/predictions/experimental/bulletin/Sep97/art03.html",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "eca79264395266f52c266148ec9d2b8ebddd5c910e846bf123934bcf3f3c9ba3",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "ellfb-Sep97_art03.html"
    },
    {
      "url": "https://docs.google.com/spreadsheets/d/1z-wPPicca67O_XLexFonC42cjY1z0Fy8ZoZirYLySNw/export?format=csv",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "fd17846fd64b48e5e82a9d8026128bbf94216fcd81fa56edfc2ca1821abef698",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "iri-alternate-sources.csv"
    },
    {
      "url": "https://iri.columbia.edu/resources/data-library/sunset/",
      "retrieved_utc": "2026-10-22T10:43Z",
      "sha256": "3851d9655535b95701954d8a20c2856e60c320189170fb1ee8eb0c3bf2d7bfa4",
      "unchanged_since_first_retrieval": true,
      "copy_held_privately_by_vultax": "iri-data-library-sunset.html"
    }
  ],
  "status_vocabulary": [
    "VERIFIED_LOCALLY",
    "DOCUMENTED",
    "INFERRED",
    "UNVERIFIED",
    "UNKNOWN"
  ],
  "quotation_policy": "Sources are paraphrased with their location; direct quotation from any single non-public-domain source is kept under 25 words across all authored material."
}