The Atmosphere

Structure and composition of the atmosphere.

The physical and chemical nature of the atmospheric layers, especially the troposphere and stratosphere. Only a brief awareness of mesosphere and thermosphere is expected. Candidates should be acquainted with, but not memorise, the various heights and temperatures associated with atmospheric stratification.

Interactions of solar radiation with the atmosphere. The effects of ionising radiation on gases in the atmosphere and living organisms.

The wavelength, frequency and intensity of radiation at the outer limits of the atmosphere and at the Earth’s surface.

Albedo, reflection and scattering of radiation. The influence of gases and water vapour on re-radiated energy.

The greenhouse effect as a natural phenomenon.

The Earth’s overall radiation budget.

The total energy received by the Earth from the Sun is equal to that ultimately emitted back into space. Candidates do not have to memorise actual values.

The formation and shielding effect of the ozonosphere.

Simple chemical equations for ozone formation and destruction. Candidates should understand that these two processes proceed at equal rates in nature.

Weather and climate.

Seasonal and diurnal variations in insolation.

Global circulation with reference to Hadley cells and the Coriolis force.

The relation between the major circulation patterns and biome development. A simple qualitative treatment of the Coriolis force as a result of the Earth’s spin.

Causes and rates of natural climate change.

The Milankovitch cycle, solar activity and volcanic activity.