Question

Distinguish between Absolute Humidity and Relative Humidity.

Answer 1

Absolute Humidity :

1. It is the measure of the actual amount of water vapour in the air, regardless of temperature.
2. It is expressed as grams of moisture per cubic meter of air(g/m3).
3. The higher the amount of water vapour, the higher is the absolute humidity.
4. In weather calculations, absolute humidity is generally not taken into account.

Relative Humidity:

1. It measures water vapour in the air but relative to the maximum vapour that the air can hold at that temperature.
2. It is expressed as the ratio (percentage value) between the absolute humidity of a given mass of air and the maximum amount of water vapour that it can hold at the same temperature.
3. Warm air possesses more water vapour than cold air, so with the same amount of absolute humidity, air will have a different relative humidity depending on temperature.
4. It is the essential characteristic of weather forecasts, which indicates the likelihood of precipitation, dew, or fog.

Answer 2

Absolute Humidity	Relative Humidity
1. It is the mass or weight of water vapour present per unit volume of air.	It is a ratio between the actual amount of water vapour present in the air and the maximum amount of water vapour it can hold at given temperature.
2. These expressed usually in grams per cubic meter of air.	It is expressed as a percentage.