Relief or Orographic Precipitation
Geography: KS3, topic 5.1.9
Relief or Orographic Precipitation
Air can rise in one of three main ways: convection precipitation, frontal precipitation, and relief or orographic precipitation.
Prevailing winds in Britain
- In Britain, the prevailing winds are from the west across the Atlantic Ocean.
- These prevailing winds bring warm, moist air.
- The air is forced to rise over the higher land in the west,
- E.g. the mountains of Snowdonia and the Lake District.
Precipitation
- The air expands and cools as it rises over the higher land.
- Cooler air cannot hold as much water vapour as a gas as warmer air.
- The air becomes saturated with gaseous water vapour.
- The gaseous water vapour condenses to liquid water droplets.
- Eventually the weight of the liquid water droplets or ice is enough for gravity to return these water droplets / ice to the surface as precipitation.
Relief or orographic precipitation
- The air then descends the eastern side of the hills and mountains.
- The air warms up as it descends and becomes drier.
Test yourself on Relief or Orographic Precipitation
In Britain, the prevailing winds are from which direction?
In which ways can the air rise?