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.
partial_press (pint.Quantity) – Partial pressure of the constituent gas
total_press (pint.Quantity) – Total air pressure
molecular_weight_ratio (pint.Quantity or float, optional) – The ratio of the molecular weight of the constituent gas to that assumed
for air. Defaults to the ratio for water vapor to dry air
pint.Quantity – The (mass) mixing ratio, dimensionless (e.g. Kg/Kg or g/g)
This function is a straightforward implementation of the equation given in many places,
such as [Hobbs1977] pg.73:
Changed in version 1.0: Renamed part_press, tot_press parameters to partial_press, total_press