Wet-Bulb Temperature Estimator

Inspectable records

Ledger state

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

Area

Thermodynamics, Fluids & Aero

Tranche

tranche-6

Evidence ID

t6-015

Ledger rows

1

No ledger note is attached.

Review findings

NEEDS_REVIEW because the instrument does not define which of the two claimed algorithms is authoritative. For a deterministic plain-arithmetic implementation, explicitly select Stull (2011), document that pressure is ignored, validate T and RH, and label the output as an empirical approximation. Alternatively, specify the complete pressure-dependent iterative psychrometric model and convergence tolerance.

Formula and scope findings

• The specification names two materially different algorithms—Stull (2011) and an iterative psychrometric energy balance—but does not select one or define the iterative equations, psychrometric constants, saturation-vapor-pressure correlation, or convergence criterion.
• The Stull formula does not use barometric pressure, so the declared P input is ignored when that method is selected. Pressure is required for a pressure-aware psychrometric calculation.
• The Stull correlation is an empirical approximation, not a general psychrometric energy-balance solution; its stated approximate validity range and error should be displayed honestly.

Unit assumptions

• Stull inputs are dry-bulb temperature T in degrees Celsius and relative humidity RH in percent from 0 to 100, not a fraction from 0 to 1.
• The Stull formula uses inverse trigonometric functions in radians.
• Barometric pressure P is not used by the Stull formula. If P is intended to affect the result, its units and the complete pressure-corrected algorithm must be specified.
• Outputs are degrees Celsius when T is supplied in degrees Celsius.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

A negative-RH input drives the RH^(3/2) term outside the real-number domain and can yield NaN unless rejected. The specification also leaves the Stull-versus-iterative method and the validity-limit branch unspecified, while RH unit convention can be interpreted as either percent or fraction.

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": {
    "method": "Stull 2011",
    "dry_bulb_C": 20,
    "RH_percent": 50,
    "pressure_kPa": 101.325
  },
  "expected_outputs": {
    "wet_bulb_C": 13.699
  },
  "working": "Use Tw = T*atan(0.151977*sqrt(RH+8.313659)) + atan(T+RH) - atan(RH-1.676331) + 0.00391838*RH^(3/2)*atan(0.023101*RH) - 4.686035. sqrt(50+8.313659)=sqrt(58.313659)=7.63634. First angle: atan(0.151977*7.63634)=atan(1.16055)=0.859571, so T term=20*0.859571=17.1914. atan(20+50)=atan(70)=1.556512. atan(50-1.676331)=atan(48.323669)=1.550105. RH term: 50^(3/2)=353.553; 0.00391838*353.553=1.38536; atan(0.023101*50)=atan(1.15505)=0.857222; product=1.18756. Therefore Tw=17.1914+1.556512-1.550105+1.18756-4.686035=13.6993 C, or 13.699 C. P is unused."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

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-tranche6/tranche6-results.json
• BOUNDARY_HAZARD_CATALOG.json