1.3 - Variations in Earth's precipitation across the Earth's surface

Question 1

Relative Humidity

Answer 1

• Ratio between actual amount of water vapour present in the air and maximum amount of water vapour the air could hold at a given temperature
• Varies with temperature
• Warm temp holds more than cool temp. (Air molecules more spread out, assuming water vapour is constant, warm air has lower saturation)
• As temperature increases, relative humidity decreases

Question 2

Clouds

Answer 2

Formation:

1) Earths surface heated, water evaporates to water vapour
2) Vapour rises, cools and condenses on condensation nuclei at dew point temperature–> clouds formed
3) Condensed droplets in the clouds collide and become larger (Coalesence)
4) Clouds grow and fall as precipitate

Question 3

Convectional Rain

Answer 3

1) Earth’s surface gets heated by the sun, water evaporates to water vapour
2) Vapour rises, cools and condenses on condensation nuclei at dew point temperature–> cumulonimbus clouds formed
3) Condensed droplets in the clouds collide and become larger (Coalesence)
4) Clouds grow and fall as convectional rain

Question 4

Relief Rain

Answer 4

1) Prevailing winds pick up moisture from sea and push warm, moist air upwards the windward side of a mountain

2) Rising moist air cools and condenses on condensation nuclei at dew point temperature. Clouds formed

3) Water droplets in clouds collide and coalesce and become heavy and large and fall as rain on the windward side.

4) Air descends the leeward side, warms and become drier.