Concept of humidity and its types

CONCEPT OF HUMIDITY
Humidity means the amount of water vapour that is held in the air. It is
basically the gaseous state of water present in air molecules. It depends on the
temperature and pressure of system under consideration.
With variation in temperature and pressure of system or surroundings, the
humidity contained in the air also varies accordingly. In cases, where the
concentration of water vapour is same, at lower temperature the humidity
present will be more as compared to higher temperature.
The Humidity of a particular air parcel is usually measured by using a
“Hygrometer”.
On a global scale, humidity is measured by using “Geosynchronous satellite”.
These satellites use infrared radiation techniques to develop water vapour
imagery and are helpful in weather forecasting.
TYPES OF HUMIDITY
Humidity is a general term that refers to the amount of water vapour present in
the atmosphere. There are three types of humidity:
1. Absolute humidity
2. Relative humidity
3. Specific humidity


ABSOLUTE HUMIDITY: Absolute humidity can be expressed as the total
amount of water vapour that is available in a given volume of air. This is
expressed as gram per cubic meter or gram per kilogram of air.
Absolute humidity can be expressed as.
Absolute humidity = Mass of water, volume of Air.
The absolute humidity completely depends on pressure and temperature.