Atmosphere and changeDescribe the functioning of the atmospheric system

interms of the energy balance between solar and

longwaveradiation.

Explain the changes in this balance due toexternal forcings (changes in solar radiation, changesin the albedo of the atmosphere and changes in the

longwave radiation returned to space). Discuss the causes and environmental consequences

of global climatechange. (4 hours)

Patterns in environmental quality and sustainability

Atmosphere and change

•Describe the functioning of the atmospheric system in terms of the energy balance between solar and longwave radiation. •Explain the changes in this balance due to external forcings (changes in solar radiation, changes in the albedo of the atmosphere and changes in the longwave radiation returned to space).

Core Unit Part 3:Patterns in environmental quality and sustainability

Lessons 1 and 2

The Earth’s atmosphere

• In groups you are going to draw a diagram from memory to learn about the different layers that make up the Earth’s atmosphere.

The global heat budget and atmospheric circulation

• Surface of the sun = 65 million billion sq. Metres

• Energy sent from each square metre could illuminate 1 million light globes

• Why do global temperatures vary?

What is going on in this photograph?

The global heat budget and atmospheric circulationIB syllabus requirements:1. Describe the functioning of the atmospheric system in terms of the energy balance between solar and longwave radiation. 2. Explain the changes in this balance due to external forcings (changes in solar radiation, changes in the albedo of the atmosphere and changes in the longwave radiation returned to space).

Using p.102-104 of Planet Geography, and the diagrams, complete the following tasks.

Task 1: Find definitions and explanations for the following words: • Insolation• Long wave radiation • Short wave radiation• AlbedoTask 2: Explain what happens to the energy from the sun when it reaches

planet Earth. You need to make reference to:1. The impact of the atmosphere2. The impact of the Earth’s surface (including type of surface ,latitude and

the shift in wave length as the sun’s energy is reflected back out)Task 3: Look at figure 3.5. 3. Using data, explain what it shows. 4. If there is a net surplus of energy towards the equator and a net deficit of

energy towards the polar regions, explain why the equator is not continually warming up and the poles continually cooling down.

Task 4: Explain what the greenhouse effect is. Why is it important?

Figure 3.4

Figure 3.4

Info cards for diagram from memory

Atmosphere

• The atmosphere is like a thin film surrounding the earth and is made up of different layers

• Half the mass of the atmosphere is found within the lowest 6km.

• 99% of the atmosphere is contained within the lowest 40km

Troposphere

• Lowest layer of the atmosphere• Contains most of the mass of the atmosphere, including

most of the dust, water vapour and pollution• Where the weather occurs• Heat does not come directly from the UV rays of the sun

like in the other layers – it is reflected from the Earth’s surface and clouds.

• Temperatures fall by approximately 6.5°C every 1,000 metres rise in altitude but this varies.

• The gases in this layer include nitrogen (78%), oxygen (21%), argon (<1%), carbon dioxide (0.003%).

• Hydrogen, helium, krypton, methane, ozone, neon and xenon are also present but comprise of only 0.001%

• Water vapour is also present in this layer but it varies enormously from place to place and day to day.

Stratosphere

• 20km – 50 km above seal level• Concentration of ozone in the stratosphere,

which absorbs UV radiation very well.• Temperatures rise with increasing altitude

in the stratosphere – top part of the layer absorbs higher levels of UV radiation so is warmer – approx 0°C

• The lower limits of the troposphere (TROPOPAUSE), the temperature is approx -50°C

Mesosphere

• 50km – 80km above sea level• Coldest part – very little cloud, dust,

ozone or water vapour to absorb heat from the sun.

• Has strongest winds in the atmosphere – up to 3,000 km/hour.

• Comprises the MESOPAUSE – which separates the mesosphere and the thermosphere above it – this is always at a constant -90°C

Thermosphere

• Highest layer of the atmosphere• Extends from approx. 80km ASL to the

furthest extents of the atmosphere.• Gases here(oxygen, hydrogen, nitrogen)

are very thin & similar to a vacuum – only 0.001% of the mass of the atmosphere.

• Gases here absorb UV radiation from the sun so heat up to high temperatures – 200°C to 1,000°C