10'2 Energy Transfer in the Atmosphere

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10.2 Energy Transfer in the Atmosphere

• Earths atmosphere is key in allowing life to
  survive
• Has the right ingredients and maintains the
  correct temperature

The composition of Earths atmosphere
See pages 436 - 437
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The Layers of the Atmosphere

• Earths atmosphere is made up of five layers.
• Troposphere
• Closest to Earths surface, 8 km to 16 km thick
• Highest density - all other layers compress it
• Almost all water vapour in the atmosphere is
  found here.
• Where most weather takes place
• Solar energy and thermal energy from Earth keep
  air moving
• Radiation from the sun heats the earth
• 15ºC (near the ground) to 55ºC at the top

See pages 438 - 439
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The Layers of the Atmosphere

• Earths atmosphere is made up of five layers.
• Stratosphere
• Second layer (10 km to 50 km above Earth)
• Ozone layer is found here
• Absorbs harmful UV radiation
• Absorbs more UV at the top, therefore..
• Temperature warms from 55ºC as altitude increases

See pages 438 - 439
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The Layers of the Atmosphere

• The remaining three layers are known as the upper
  atmosphere.
• Mesosphere
• Thermosphere
• Exosphere

See pages 438 - 439
The layers of Earths atmosphere
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The Layers of the Atmosphere

• The remaining three layers are known as the upper
  atmosphere.
• Mesosphere
• 50 km to 80 km above Earth
• Temperatures decrease with altitude to 100ºC
• No ozone to absorb UV
• This layer is where space debris (dust, meteors)
  burns up when it begins to hit particles.

See pages 438 - 439
The layers of Earths atmosphere
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The Layers of the Atmosphere

• The remaining three layers are known as the upper
  atmosphere.
• Thermosphere
• 80 km to 500 km above Earth
• Temperatures can reach 1500ºC to 3000ºC
• Trace O2 absorbs solar radiation
• This is where the Northern Lights, aurora
  borealis, are found.
• Charged particles in Earths magnetic field
  collide with particles in the thermosphere.

See pages 438 - 439
The layers of Earths atmosphere
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The Layers of the Atmosphere

• The remaining three layers are known as the upper
  atmosphere.
• Exosphere
• 500 km to 700 km above Earth
• Atmosphere merges with outer space.

See pages 438 - 439
The layers of Earths atmosphere
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Radiation and Conduction in the Atmosphere

• Almost all of the thermal energy on Earth comes
  from the Sun.
• Only a small fraction of the solar radiation that
  reaches Earth.
• Most thermal energy is transferred near the
  equator
• Direct source of solar radiation
• Insolation
• Amount of solar radiation an area receives (
  W/m2)
• Decreases if
• Dust and smoke in the way
• Angle of incidence of the solar radiation is too
  great.

Angle of incidence
See pages 440 - 441
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Radiation and Conduction in the Atmosphere

• Solar radiation does NOT heat the atmosphere
  directly
• Earths surface absorbs radiation, heats up, then
  
• radiates the thermal energy into the atmosphere.
• Provides 70 of the airs thermal energy
• Convection currents in the air spread thermal
  energy
• (See Figure 10.19 on Page 441)

See pages 440 - 441
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The Radiation Budget and Albedo

• Radiation budget
• Explains where the solar radiation goes
• Earths radiation budget heat gained heat
  lost
• Incoming Outgoing radiation balanced
• If all 342 W/m2 of solar radiation that reaches
  Earth was stored in the atmosphere, it would be
  far too hot

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The Radiation Budget and Albedo

• Radiation budget
• Earths radiation budget heat gained heat
  lost
• Of the solar radiation that goes towards Earth
• 58 reaches Earths surface
• 9 reflected by surface

• Reflected
• 15 by clouds
• 7 by particles

• Absorbed
• 20 is absorbed by clouds
• and the atmosphere

• Radiation that comes to Earth
• 23 drives the water cycle
• 7 creates wind
• 19 re-radiated from Earths surface

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The Radiation Budget and Albedo

• Albedo - amount of energy reflected by a surface.
• Light-coloured surfaces (snow, sand) have a high
  albedo and reflect energy.
• Dark-coloured surfaces (soil, water) have a low
  albedo and absorb energy.

See pages 442 - 443
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Prevailing Winds

• Prevailing winds - winds that are typical for a
  location
• Winds in B.C. usually blow in from the ocean.
• Warm air rises, cools and condenses ? causing
  rain as it is forced up the mountain slopes
• Air gets drier as it moves inland, continuing to
  drop precipitation.
• Dry air rushes down the far side of the mountains
  into the prairies.

See pages 448 - 449
The prevailing winds off British Columbias
coast, crossing into Alberta.