weather in the British isles

Question 1

precipitation

Answer 1

any form of water moving through the air towards the surface of the Earth. this includes, drizzle, rain, fog, mist, dew, frost, hail, sleet and snow

Question 2

formation of orographic/relief rainfall

Answer 2

1. as air moves inland and meets a relief barrier it is forced to rise
   - when air rises it expands and cools which causes relative humidity to increase
2. when relative humidity reaches 100% it reaches dew point and condensation will occur and latent heat will be released
3. cloud formation occurs and latent heat will result in further thermal uplift, cooling and cloud formation
4. therefore, rainfall will be experienced in these mountainous areas
5. as the descending air on the leeward side contracts and warms the relative humidity will decrease, resulting in dry conditions with lower rainfall totals
   eg Scottish highlands

Question 3

adiabatic cooling

Answer 3

process of reducing heat through a change of air pressure caused by volume expansion

Question 4

relative humidity
absolute humidity

Answer 4

1. the amount of water vapour in the air expressed as % of the total amount of water vapour air can hold at that temperature
2. used to express the mass of water vapour in a given volume of air (cubic meters)

Question 5

dew point

Answer 5

the temperature to which a parcel of unsaturated air must be cool in order to become saturated

Question 6

formation of frontal (cyclonic) rainfall

Answer 6

1. two air masses meet, e.g polar front (60°N/S) –> warm tropical air meets cold polar air.
2. here the air becomes unstable as warm and cold air don’t mix
3. warm air rises over the colder (dense) air
4. as the air expands it cools adiabatically, leading to precipitation
5. frontal rain is associated with depressions and are common across Western Europe

Question 7

formation of convectional rainfall

Answer 7

1. this type of rainfall is common in summer months in the UK
2. incoming short wave radiation reaches the ground which is converted into long wave heat energy
3. this heat energy heats the air which then rises (thermal uplift)
4. as the air rises, it cools and relative humidity increases. condensation occurs at dew point temperature
5. the release of latent heat produces further uplift, cooling and condensation, producing towering cumulonimbus clouds which produce heavy convectional rainfall