# vapor_pressure¶

metpy.calc.vapor_pressure(pressure, mixing_ratio)[source]

Calculate water vapor (partial) pressure.

Given total pressure and water vapor mixing_ratio, calculates the partial pressure of water vapor.

Parameters
Returns

pint.Quantity – Ambient water vapor (partial) pressure in the same units as pressure

Notes

This function is a straightforward implementation of the equation given in many places, such as [Hobbs1977] pg.71:

$e = p \frac{r}{r + \epsilon}$

Changed in version 1.0: Renamed mixing parameter to mixing_ratio