What is Precipitation?
Any form of moisture reaching the earths surface from the atmosphere is called precipitation.The types of precipitation are described below.It is one of major part in the hydrology cycle.There are three classification of rain based on the intensity of rain.
- Rainfall with an intensity of 2.5mm per hour is called light rain
- Rainfall with an intensity between 2.5mm per hour and 7.5mm per hour is called as moderate rain
- Rainfall exceeds 7.5mm per hour is called ad heavy rain
- Precipitation is measured by an instrument called rain gauge which is also known as hyetometer,Ombrometer or pluviometer.
Forms of precipitation
- The forms of precipitation are
- Drizzle: Size of droplet is less than 0.5mm
- Rain: Size of droplet is more than 0.5mm
- Glaze: When the drizzle freezes it is known as glaze
- Steel:The frozen rain drops are cooled to ice stage while falling
- Snow: The water vapour when directly changed to ice is known as snow
- Hail: Lumps of ice with more than 5mm diameter is known as hail.
Types of Precipitation
There are three types of precipitation
1.Cyclonic Precipitation ( Non frontal)
Lifting of air masses converging into low pressure area of cyclone is known as cyclonic precipitation
Convective precipitation is another classification of types of precipitation.It is caused by rising of warmer and lighter air in colder and denser surroundings.
3. Orographic Precipitation
This type of precipitation occurs when the warm moisture laden air is lifted upwards due to obstruction of hill.In this case the rainfall occurs only along one side of the hill.The other side is dry and is known as rain shadow region.