Rainfall

 Some Key terms.

Precipitation - Any moisture that falls to the ground. For example, rain snow and hail are all forms of precipitation.

Condensation -  The change or conversion of vapour or gas to liquid. In the case of rainfall, water vapour is changed to liquid.

Saturation - the state or process that occurs when no more of something can be absorbed, combined with, or added. In the case of rainfall, when the clouds cannot absorb any more water they are said to be saturated.

Relief rainfall
Relief rainfall occurs when air has been blown over the sea and is then forced up over an area of high land. The air becomes cooler as it rises and condenses to form clouds. As the clouds become saturated, rainfall occurs.

Frontal rainfall
Frontal rainfall occurs when warm air is forced to rise over cold air. The moisture in the warm air condenses as it cools which causes clouds. When the clouds experience saturation, precipitation (rainfall) occurs.

Convectional rainfall
Occurs mostly in tropics where it is hot. The air is heated by the sun and this hot air rises. As the air rises it cools and condenses to form clouds. These clouds become saturated and cause rainfall. If the air is hot enough, it rises very quickly and can cause thunderstorms.