Rainfall or precipitation is a key to organic life in the world and it all gets delivered the same way, but there are different ways that it is formed. There are 3 main ways the formation of rainfall occurs.
The first type, orographic, is where there is a mountain and a large body of water involved. The steps of the formation in this type are as follows.
- Warm, moist air is blown from the ocean.
- The air gets pushed up the side of the mountain.
- When it reaches the top, it cools and condenses to form clouds.
- These clouds release rain at the top of the mountain.
Those stages only occur to the side that is facing the body of water. On the other side of the mountain hardly any precipitation occurs and it is very dry. This is because all the moisture in the air has been taken away, this area is called the ain shadow area. The intensity in this type is moderately light. This is because not much moisture has been collected to form the clouds, this differs a lot to convectional rainfall.
The second type is convectional. This is the type that most of us get exposed to and it is the most common type. In convectional rainfall the sun does a lot of the work, here are the steps of a convectional formation.
- The sun heats up a body of water.
- The water evaporates and the water vapour rises up in the air.
- The water vapour cools as it gets higher and condenses to form clouds.
- These clouds carry on collecting water vapour till they are ready to release their rain.
If you look at areas which use this type of rainfall you will see that here you can have large, intense amounts of rainfall. This is because there is a lot more water vapour in these clouds than in other types, due to the large factor of the sun.
The final type of rainfall for this section is frontal rainfall. Frontal rainfall is where hot air is forced to rise over a cold front of air. Here are the steps of a typical frontal formation.
- A cold mass of air meets a hot mass of air
- The two temperatures of air don't mix, but instead form fronts.
- The hot air is lighter than the cold air and is therefore forced to rise.
- As the hot air rises, the water vapour in that air condenses.
- The condensations causes rain.
This type is the lightest intensity of rainfall of all. This is because there is no mass of water involved in the formation of this type.
This brings us to the end of the section.