HIGHER GEOGRAPHY – ATMOSPHERE HOMEWORK 1
QUESTIONS
1. Study figure 2.2 on page 6 of the Core Textbook
Describe and explain exchanges that result in the Earth’s surface absorbing
only 51% of the solar energy that reaches the outer atmosphere
2. With the aid of an annotated diagram, explain why the tropical latitudes
receive more of the sun’s energy than polar regions
16 marks
GENERAL POINTS
Question 1
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Answers should refer to both reflection and absorption
Albedo – reflection of solar insolation from the earth’s surface
Textbook includes reflection from clouds in the albedo affect – easier to separate
out
You need to include some of the %ages in your answer
Like the HW you will usually be given a diagram as a prompt in the exam
Use the figures – they alone could get you up to 3 marks out of 8!
Use language like ‘long wave radiation’
Question 2
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Not referring to a  b, surface area x etc. in actual answer
These can’t just be shown on the diagram – when talking about the depth of
atmosphere mention the letter you have used when labelling your diagram
Saying the radiation has a greater distance to travel – not in relative terms
Only distance that is greater is depth of atmosphere
Extend this point for 2 marks…… More energy is lost through absorption and
reflection before it can reach the earth’s surface
Be careful about making sweeping statements like the ice caps will reflect solar
energy back into space while the darker topics absorb all the energy
Reality is both reflect – the albedo (rate of reflection) is just greater at the Poles
MODEL ANSWER
1. Reflection from the atmosphere accounts for a 26% reduction in the amounts of
solar energy. Large amounts are reflected by clouds, gas and dust in the
atmosphere. A further 6% is reflected from the earth’s surface and emitted as
long wave radiation.
The amount of reflectivity is linked to the Earth’s albedo. At the poles this is much
higher than the equator due ice and snow and the high reflective quality of white
surfaces.
Absorption by the atmosphere reduces the solar energy by a further 18%. The
majority of absorption is by gases, cloud and dust in the atmosphere. This means
that only around 50% of the solar energy which reaches the edge of the
atmosphere is actually absorbed by the earth’s surface.
2. As can be seen from the diagram the sun’s rays are concentrated on tropical
latitudes. The intensity of insolation is greatest here as the rays strike the earth
at a vertical angle.
The sun’s rays have less atmosphere to pass through at this point (a  b on diagram
compared to c  d), therefore less energy is lost at tropical latitudes through
absorption and reflection.
The angle of the sun in the sky decreases towards the poles and due to the earth’s
curvature the heat energy is spread over a much greater surface area (x  y on
the diagram compared to t  v).
Differing albedos also lead to a surplus at the tropics – darker forest areas absorb
solar radiation, whereas ice covered surfaces found at higher latitudes reflect
radiation.
Between the Tropics, centring on the equator, the rays from the noon day sun are
high in the sky throughout the year (directly overhead on two days of the year)
focusing energy for 12 months. At the Poles there is zero solar insolation at the
winter solstice unlike the equator where the sun shines throughout the year.