1. b. Composition of the Atmosphere
Gas %
Importance for atmosphere / climate & Life N
Oxygen
78.09
20.95
Used in Proteins
Respiration
Water Vapour
4.0
Cloud formation, reflects and absorbs radiation keeps temps constant. Used by life after circulated by H20 cycle
CO2
0.03
Absorbs long wave-length radiation. Increases global temps via natural greenhouse effect. Anthropogenic release increases this risk. Used in Photosynthesis O3
Absorbs incoming solar radiation is a greenhouse gas
Argon
0.93
None
Dust
Trace
Absorbs and reflects radiation. Volcanic eruptions release it. Form condensation nuclei for cloud formation
Pollutant Gases SO2, NO, CH4
Affect levels of incoming solar radiation and cause acid rain
Chemoautotrophs use CH4 as a source of C. Still important in deep oceans

2. ‘Dynamic Equilibrium’:
Exists in the atmosphere where composition only changes over very long timescales.
Photosynthesis
Respiration
Respiration
Photosynthesis
Rates of P and R vary over different timescales so concentrations of C02 fluctuates

4. ‘Temporal Changes in the Atmosphere (Changes with Time)’:
(i) CO2 changes in a 24h cycle. How and Why?
(ii) CO2 fluctuates more in summer. Why?
(iii) Water vapour varies too…. Why?
(iv) Gases can change in the longer term…. Why?

5. ‘Changes in the Atmosphere with altitude (Height):
(i) Why does ozone (O3) naturally increase in the stratosphere?
(ii) Why does the temperature decline with rising altitude in the troposphere?
This helps produce the layered structure you
have seen.

6. Solar Radiation and the Atmosphere
(i) Explain how solar radiation heats the atmosphere? (p.80). Use a diagram next to summarise the heat budget of the atmosphere.
(ii) Get all of the key terms for your notes.
Nuclear Fusion. / Electromagnetic Radiation
Global Climate Change
(iii) Draw a diagram using Waugh to show the percentages of total radiation entering the atmosphere

8. How the sun heats the Atmosphere
Sun: Incoming solar radiation (Short Wavelength)
The atmosphere is heated in two ways
Thermosphere
Mesosphere
Is warmed directly by absorption by O3, water vapour, C02 and Ice and Dust (‘TOP DOWN’)
Stratosphere
Troposphere
Most (94%) of atmosphere is heated ‘bottom up’ by heat energy that is radiated from the ground surface
Ground