Beaufort Wind Scale Lookup mechanism

Model scope

The specification is close to a valid WMO lookup instrument, but it needs an explicit unit contract, measurement convention, boundary policy, and clarification that the WMO table—not the approximate power-law relation—controls the Beaufort number. The honest label should state: 'Beaufort force from sustained wind speed; speed unit and averaging/reference-height convention required.'

• The relation v = 0.836·B^1.5 is only an approximate Beaufort relation when v is in m/s and B is dimensionless; it is not, by itself, the standard classification algorithm. The WMO table boundaries must define the returned category.
• The input claim 'wind speed (any unit)' is incomplete: the implementation must require a unit, convert it to the table unit, and reject or explicitly handle unknown units.
• The Beaufort scale convention requires a sustained wind-speed averaging period and reference height; standard WMO tabulations use approximately 10-minute mean wind at 10 m above open ground or sea. Gust speed, instantaneous speed, and unqualified sensor height can produce different categories.

Units and conventions

• Lookup-table speeds are treated as 10-minute mean wind speeds at 10 m, expressed in m/s after conversion.
• For the knot test vector, 1 international knot = 0.514444 m/s.
• The approximate relation v = 0.836·B^1.5 assumes v in m/s and B as a numerical Beaufort force.
• Descriptions are the standard WMO-style land and sea descriptions; the instrument should specify which description context is displayed.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "wind_speed": 0,
    "unit": "m/s",
    "measurement": "10-minute mean at 10 m"
  },
  "expected_outputs": {
    "beaufort_number": 0,
    "land_description": "Calm; smoke rises vertically.",
    "sea_description": "Sea like a mirror."
  },
  "reference_data": {
    "beaufort_rows": [
      {
        "force": 0,
        "wind_speed_m_s": "0.0-0.2",
        "land_description": "Calm; smoke rises vertically.",
        "sea_description": "Sea like a mirror."
      }
    ],
    "source_convention": "WMO Beaufort scale, widely tabulated standard value"
  },
  "working": "Input is already in m/s: 0 m/s. The value is in the force-0 row, 0.0-0.2 m/s. Therefore Beaufort force = 0. The relation also gives v = 0.836·0^1.5 = 0 m/s, but the table determines the category."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification says wind speed may use any unit but does not define mandatory unit metadata, parsing, or behavior for extreme out-of-range values. A bare value of 10 can therefore yield B5 when read as m/s or B3 when read as mph, and an extreme finite input can overflow during conversion unless saturation or rejection is implemented.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json