Lifting Condensation Level (LCL) Height

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

Tranche

tranche-5

Evidence ID

t5-005

Ledger rows

1

No ledger note is attached.

Review findings

The honest-label wording correctly identifies this as a rule-of-thumb approximation. Release requires explicit temperature units, an explicit output unit or both-unit behavior, and validation that dew point is less than or equal to temperature.

Formula and scope findings

• Espy's rule, LCL(m) ≈ 125·(T−Td), is a standard rule-of-thumb when T and Td are in °C (or temperature differences expressed in K) and the result is in meters.
• The specification does not define the required input temperature units or whether the output is meters, feet, or both.
• The specification does not state the domain constraint Td ≤ T; allowing Td > T produces a physically invalid negative cloud-base height.

Unit assumptions

• The coefficient 125 applies to a temperature difference in °C; a difference in kelvins has the same numerical value.
• The primary result is assumed to be in meters.
• Feet are obtained with 1 m = 3.28084 ft.
• Fahrenheit inputs must be converted to °C before applying the formula; applying 125 directly to a Fahrenheit difference is invalid.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define temperature units or validation behavior for Td greater than T, and an extreme but finite JavaScript input overflows to Infinity. A robust implementation should require compatible temperature units, flag negative LCL results, and handle numeric overflow explicitly.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "temperature": 25,
    "dew_point": 17,
    "temperature_unit": "°C",
    "output_unit": "m_and_ft"
  },
  "expected_outputs": {
    "lcl_height_m": 1000,
    "lcl_height_ft": 3280.84
  },
  "working": "T − Td = 25 − 17 = 8 °C. LCL = 125 × 8 = 1000 m. Feet = 1000 × 3.28084 = 3280.84 ft."
}

Related workflows

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json