metpy.calc.relative_humidity_from_specific_humidity(pressure, temperature, specific_humidity)[source]#

Calculate the relative humidity from specific humidity, temperature, and pressure.


pint.Quantity – Relative humidity


>>> from metpy.calc import relative_humidity_from_specific_humidity
>>> from metpy.units import units
>>> relative_humidity_from_specific_humidity(1013.25 * units.hPa,
...                                          30 * units.degC, 18/1000).to('percent')
<Quantity(68.3229304, 'percent')>


Employs [WMO8] eq. 4.A.16 as derived from WMO relative humidity definition based on vapor partial pressures (eq. 4.A.15).

\[RH = \frac{w}{\epsilon + w} \frac{\epsilon + w_s}{w_s}\]

given :math: w = frac{q}{1-q}

  • \(w\) is mixing ratio

  • \(w_s\) is the saturation mixing ratio

  • \(q\) is the specific humidity

  • \(\epsilon\) is the molecular weight ratio of vapor to dry air

  • \(RH\) is relative humidity as a unitless ratio

Changed in version 1.0: Changed signature from (specific_humidity, temperature, pressure)

Examples using metpy.calc.relative_humidity_from_specific_humidity#

Cross Section Analysis

Cross Section Analysis

Isentropic Analysis

Isentropic Analysis