Calculator Input Panel
Use the advanced options to solve either potential temperature or parcel temperature with flexible units and a custom dry-air exponent.
Formula Used
Potential temperature equation:
θ = T × (P₀ / P)(Rd / cp)
Inverse form: T = θ × (P / P₀)(Rd / cp)
- θ = potential temperature.
- T = actual air temperature in Kelvin.
- P = ambient pressure.
- P₀ = reference pressure, usually 1000 hPa.
- Rd = gas constant for dry air.
- cp = specific heat at constant pressure.
This calculator assumes a dry adiabatic process. It is commonly used in meteorology to compare air parcels measured at different pressures on an equal basis.
How to Use This Calculator
- Choose whether you want to solve for potential temperature or parcel temperature.
- Enter the measured value in the correct unit system.
- Supply ambient pressure and the reference pressure.
- Adjust dry-air constants if you need a custom thermodynamic setup.
- Optionally enter a target pressure to estimate parcel temperature on the same dry adiabat.
- Press Calculate Now to show the result above the form.
- Review the Plotly graph, then export the output as CSV or PDF.
Example Data Table
| Temperature (°C) | Pressure (hPa) | Reference Pressure (hPa) | Potential Temperature (K) |
|---|---|---|---|
| 25 | 950 | 1000 | 302.555 |
| 15 | 850 | 1000 | 301.855 |
| 5 | 700 | 1000 | 308.011 |
| -10 | 500 | 1000 | 320.826 |
Frequently Asked Questions
1) What is potential temperature?
Potential temperature is the temperature an air parcel would have if moved dry adiabatically to a chosen reference pressure, usually 1000 hPa.
2) Why is Kelvin used in the formula?
The equation requires absolute temperature. Kelvin keeps the thermodynamic relationship physically valid and avoids errors caused by shifted temperature scales.
3) Why is 1000 hPa often used as reference pressure?
Meteorology commonly uses 1000 hPa because it is close to average sea-level pressure, making comparisons between air parcels easier and more consistent.
4) What does a higher potential temperature mean?
A higher potential temperature usually indicates a warmer, less dense parcel when compared at the same reference pressure. It often helps assess atmospheric stability.
5) Does this tool include moisture effects?
No. This version uses the dry adiabatic relation. Moist processes require virtual, equivalent, or wet-bulb potential temperature methods instead.
6) Can I use units other than hPa?
Yes. The calculator accepts hPa, mb, Pa, kPa, and bar. It converts them internally before applying the thermodynamic equation.
7) What is kappa in this calculator?
Kappa is the exponent Rd/cp. For dry air, it is commonly close to 0.286 and controls the pressure dependence in the formula.
8) What does the graph show?
The graph shows the dry adiabatic temperature profile associated with the calculated potential temperature across the pressure range you selected.