Description
Subtract a supplied ground-height datum from a layer height.
Atmospheric values depend on pressure order, vertical datums, moisture definitions and reference conditions. Specific humidity uses moist-air mass as its denominator, whereas mixing ratio uses dry-air mass. A pressure-order flag differs from a temperature inversion, and a logarithmic-pressure weight can represent extrapolation.
Subtract a supplied ground-height datum from a layer height.
When to use this tool
Use Boundary Layer Height Datum Offset when you already have suppliedGroundDatumHeight, reportedLayerHeight and need to subtract a supplied ground-height datum from a layer height.
How to use the tool and how it works
- Enter suppliedGroundDatumHeight, reportedLayerHeight. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedGap. Use the output convention below.
Return reportedLayerHeight-suppliedGroundDatumHeight, retaining signs.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| suppliedGroundDatumHeight | Supplied Ground Datum Height | Required. Finite number. |
| reportedLayerHeight | Reported Layer Height | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedGap | Signed Gap | Required. Finite number. |
{
"input": {
"suppliedGroundDatumHeight": 12,
"reportedLayerHeight": 17
},
"output": {
"signedGap": 5
}
}Limitations and assumptions
- Both heights need the same unit/datum. No layer is detected, terrain retrieved, vertical reference transformed or atmospheric boundary-layer model fitted.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use calibrated profile and station data with the complete atmospheric model. Preserve datum, humidity and pressure conventions and assess uncertainty before interpreting local terms as an observed layer, state or forecast.
References
Similar or alternative tools
- Radiosonde Ascent Speed
Calculate supplied radiosonde mean vertical speed.
- Atmospheric Column Layer Dry Mass
Calculate a nominal dry-air column mass from supplied pressure bounds.