Unit 2 Water Cycle

Question 1

How does precipitation form?

Answer 1

1. A small particle in the atmosphere causes water vapour to form and condensation takes place. These particles are known as condensation nuclei.
2. Cooling of the air below the dew point.

Question 2

What is the dew point?

Answer 2

The temperature at which condensation takes place at. Its dependant on the humidity of the air.

Question 3

Why does air cool in the atmoshpere?

Answer 3

As altitude increases temperature decreases.

Question 4

What are the 3 main mechanisms of air uplift? (precipitation)

Answer 4

• Frontal rainfall
• Convectional rainfall
• Orographic rainfall

Question 5

What is frontal rainfall?

Answer 5

Occurs when tropical air meets cold polar air. The combination of hot and cold weather fronts causes precipitation. Warm air is less dense than cold air so goes above the colder air and water vapour condenses into water and falls as raindrops.

Question 6

What is orographic rainfall?

Answer 6

The rainfall produced when moisture landed air is forced upwards over higher ground such as mountains, producing clouds and potentially producing precipitation if it becomes to heavy. The other side of the mountain in known as the rain shadow as it receives no rainfall and conditions are typically dry.

Question 7

Where does orographic rainfall occur the most?

Answer 7

Upland western regions of the UK, as westerly winds from the Atlantic ocean rise over mountains such as Snowdonia.

Question 8

What is convectional rainfall?

Answer 8

Convection clouds form inn an unstable atmosphere by ‘bubbles’ of buyout air rising up in the atmosphere (due to evaporation). As bubbles rise, they cool and condense forming water vapour, and once they get to a certain weight and height they fall causing precipitation.

Question 9

What is meant by cumulonimbus?

Answer 9

Clouds which are produced on a very ht day due to vapid evaporation and condensation of water vapour.