# mixing_ratio¶

metpy.calc.mixing_ratio(partial_press, total_press, molecular_weight_ratio=<Quantity(0.62195691, 'dimensionless')>)

Calculate the mixing ratio of a gas.

This calculates mixing ratio given its partial pressure and the total pressure of the air. There are no required units for the input arrays, other than that they have the same units.

Parameters
Returns

pint.Quantity – The (mass) mixing ratio, dimensionless (e.g. Kg/Kg or g/g)

Notes

This function is a straightforward implementation of the equation given in many places, such as [Hobbs1977] pg.73:

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

Changed in version 1.0: Renamed part_press, tot_press parameters to partial_press, total_press