Description
Return water-vapor mixing ratio on a dry-air basis.
Atmospheric state formulas depend on absolute temperature, pressure reference, water mass/volume bases and layer assumptions. Local adiabatic, hydrostatic or precipitation terms can illustrate a supplied model without reconstructing an actual profile, validating an instrument or predicting weather hazards.
Return water-vapor mixing ratio on a dry-air basis.
When to use this tool
Use Moist Air Mixing Ratio Vapor Pressure when checking the stated atmospheric pressure, temperature, humidity or water-basis term.
How to use the tool and how it works
- Enter vaporPressure, totalPressure, molecularMassRatio. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read mixingRatio. Use the output convention below.
Return water-vapor mixing ratio on a dry-air basis. Require vaporPressure >= 0, totalPressure > vaporPressure and molecularMassRatio > 0; mixingRatio = ratio*vaporPressure/(totalPressure-vaporPressure).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| vaporPressure | Vapor Pressure | Required. Finite number; minimum 0. |
| totalPressure | Total Pressure | Required. Finite number. |
| molecularMassRatio | Positive supplied water-vapor/dry-air molar-mass ratio. | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| mixingRatio | Water mass per dry-air mass, not per total moist-air mass. | Required. Finite number. |
{
"input": {
"vaporPressure": 2000,
"totalPressure": 100000,
"molecularMassRatio": 0.622
},
"output": {
"mixingRatio": 0.012693877551020407
}
}Limitations and assumptions
- The molecular-mass ratio and ideal partial-pressure convention are supplied; this is mass water per mass dry air, not specific humidity.
- 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 verified observations and an appropriate complete thermodynamic/profile analysis with explicit units, references and moisture assumptions for meteorological conclusions.
References
Similar or alternative tools
- Humidity Mixing Basis Residual
Check supplied specific humidity against mixing ratio.
- Dewpoint Depression Observed Term
Return observed temperature-minus-dewpoint depression.