Key terms

Question 1

Air mass

Answer 1

• a large body of air w relatively similar temp + humidity characteristics

Question 2

Melting

Answer 2

• change from a solid to liquid

Question 3

Sublimation

Answer 3

• change from a solid to gas, w/o melting

Question 4

Deposition

Answer 4

• direct placement of water vapour onto a solid (e.g. ice or veg.)

Question 5

Snow

Answer 5

• single flake or mass of flakes of frozen water. May form clouds.

Question 6

Sleet

Answer 6

• partially melted snow

Question 7

Conventional rainfall

Answer 7

• when land becomes v. hot + heats air above it
• air expands + rises
• as it rises, cooling + condensation takes place
• if continues to rise, rain falls

Question 8

Frontal (cyclonic) rainfall

Answer 8

• when 2 air masses w diff. temp characteristics merge
• warm air mass forced to rise over colder air mass, causing it to cool, condense + form clouds + rain

Question 9

Orographic (relief) rainfall

Answer 9

• when airstream forced to rise over a barrier (e.g. mountain) + as air rises, it’s cooled

Question 10

Rainshadow

Answer 10

• leeward side of hills, that has relatively light rainfall compared w windward side

Question 11

Thunderstorm

Answer 11

• rapid cloud formation + heavy precipitation in unstable air conditions

Question 12

Conditional instability

Answer 12

• caused by air continuing to rise bc has became unstable (e.g. by being forced up over high ground)

Question 13

Front

Answer 13

• boundary between warm air mass + cold air mass, resulting in frontal rainfall

Question 14

Fog

Answer 14

• cloud at ground lvl

Question 15

Radiation fog

Answer 15

• forms on clear, calm nights when land surface loses heat rapidly
• air above is cooled below its dew point + condensation takes place

Question 16

Dew point

Answer 16

• T°C when relative humidity is 100%

Question 17

Radiation cooling

Answer 17

• cooling of Earth’s surface + air, caused by heat lost to space by longwave radiation from clouds + gases in atmo.

Question 18

Smog

Answer 18

• fog containing impurities, mainly nitrogen oxides + volatile organic compounds from domestic fires, industrial furnaces, power stations + internal combustion engines

Question 19

Inversion

Answer 19

• cold air at surface is replaced by higher warmer air

Question 20

Advection fog

Answer 20

• formed by warm air flowing over a cold surface, being chilled, reaching dew point + condensation taking place, close to ground surface

Question 21

Steam fog

Answer 21

• fog where cold air blows over a much warmer surface
• evaporation from water quickly saturates air + resulting condensation leads to steaming

Question 22

Coalescence

Answer 22

• 2 droplets/crystals combine to form rain/snow

Question 23

Aggregation

Answer 23

• 2 ice crystals collide to form snow

Question 24

Accretion

Answer 24

• ice crystal collects a water droplet, forming hail