Structure Of Atmosphere

Question 1

What is the order from Earth upwards?

Answer 1

Troposphere
Stratosphere
Mesosphere
Thermosphere

Question 2

Explain the troposphere?

Answer 2

• 8-17km from Earth
• Affects weather and climate
• Temp decreases with altitude (6.5C per km)
• Turbulence as warm air rises and cold air sinks
• Clouds= water vapour evaporated + cools + condenses
• Upper boundary = tropopause. This is located at 8km above the poles and 17km above the tropics (can vary seasonally). Temp remains constant

Question 3

Explain the stratosphere?

Answer 3

• Extent = 50km from Earth
• Temp increases as altitude increases as Ozone absorbs UV and warms
• Free of cloud and dust
• Warming is greater over poles as temp differences causes strong horizontal air movements
• ozone layer absorbs + filters out UV (global warming = changes)
• upper extent = stratopause
• contains jet streams

Question 4

What discoveries were made about the ozone (stratosphere) in the 1980s?

Answer 4

Scientists discovered hole in ozone above Antarctica - size of USA + 10km thick

Ozone is broken up by reaction with chlorine monoxide (from CFCs) - ice particles above Antarctica turn chlorine into C.monoxide

At least 100 years to repair

Question 5

Explain the mesosphere?

Answer 5

Temp decreases as altitude increases as warmed by stratosphere - warming effect lessened as move away

Boundary = mesopause

Question 6

Explain the thermosphere?

Answer 6

Temp increases as altitude increases as small amounts of O2 absorbs UV

Question 7

What happens to air pressure as altitude increases?

Answer 7

Fewer air molecules + move slower so colder