Question

How would I convert relative humidity to specific humidity? The variables I have are vapor pressure,...

How would I convert relative humidity to specific humidity? The variables I have are vapor pressure, air temperature, and relative humidity.

Homework Answers

Answer #1

We know that

Relative humidity can be defined as the ratio of vapour pressure of water (at a temperature and pressure) to the vapour pressure of gas over water φ = pw / pws 100%

specific humidity can be defined as the ratio of the mass of water vapor in air to the total mass of the air ans water vapour xs = 0.622 pws / (pa - pws)   

Where

φ = relative humidity

xs = specific humidity of air vapor mixture (kg/kg)

ρws = density of water vapor

ρ = density of the moist or humid air

we have air temperature , vapour pressure and relative humidity

φ = pw / pws

xs = 0.62 pws / (pa - pws)   

so on rearranging we may say that

xs = 0.62 φ ρws / (ρ - ρws)

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