2012
Question 6: Atmosphere
(a) With the aid of an annotated diagram or diagrams, explain why there is a
surplus of solar energy in the tropical latitudes and a deficit of solar energy
towards the poles. (8 Marks)
*(EARTH’S ENERGY BALANCE)*
Assess out of 8 marks awarding a maximum of 6 marks if there is no annotated
diagram.
The Sun’s rays are concentrated on tropical latitudes where the rays strike vertically. The rays
have less atmosphere to pass through at the Tropics so therefore, there is less energy lost
through absorption and reflection. The Sun’s angle in the sky decreases towards the Poles
due to the earth’s curvature which spreads heat energy over a larger area. The albedo differs
between Tropics and Poles. At the Tropics there are rainforests which are dark in colour and
the surfaces absorb radiation. At the poles you can find ice covered areas which reflect
radiation. The sun is higher in the sky between the Tropics throughout the year which helps
to focus the energy and lastly there is no solar insolation at the winter solstices at the Poles.
2012
(b) Study Diagram Q6.
Describe the possible consequences of global warming throughout the world. (6
MARKS)
Diagram Q6: Newspaper Extract
“Global warming is causing an increase in temperature throughout the World. In Scotland,
some areas of Glasgow near the Clyde are in danger of serious flooding—and the risk is only
going to get worse because of climate change due to global warming.” The Herald, 28
November 2009
Assess out of 6 marks awarding up to 2 marks for authentic named examples.
Descriptions of possible consequences may include:
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Global sea levels will rise due to the melting of ice sheets/icebergs/glaciers. Lowlying coral reefs e.g. Maldives are at risk of flooding. Venice is already affected by
subsidence due to groundwater levels dropping. Rising sea levels can also make the
impact of tsunamis worse.
More extreme weather (and more variable) including floods, droughts, hurricanes and
tornadoes. These include hurricane Katrina in 2004.
Warming in the Northern Latitudes e.g. Scotland and some countries in the lower
latitudes e.g. China might become cooler.
Increase in diseases such as malaria and yellow fever because warmer areas are
expanding.
Extension and retreat of vegetation by altitude and latitude.
Impact on wildlife eg extinction of species.
Change in length of growing season.
Some areas will become wetter, others drier.
Changes to ocean current circulation.
Changes in atmospheric patterns linking to monsoon, El Nino, La Nina etc.
2011
Assess out of 6 marks with maximum 3 marks for each air mass.
Award 1 mark for origin per air mass and the balance for characteristics/nature.
Maritime Tropical (mT)
The South-Western Monsoon comes from the Atlantic ocean and the Gulf of Guinea, which
lie in the tropical latitudes (origin). It brings hot weather and high humidity (how much water
there is in the air). It brings varied weather conditions and its nature can be seen to be
unstable.
Continental Tropical (cT)
The Harmattan comes from the Sahara Desert, which lies in the tropical latitudes. It brings
very hot to hot weather and low humidity. The nature of this air mass is stable but because of
the dust that is carried by the wind, there is often poor visibility.
Question 1: Atmosphere (continued)
Study Maps Q1A and Q1B and Diagram Q1.
(b) Describe and explain the variation in rainfall within West Africa
(b) Assess out of 12 marks with maximum 8 marks for either description or explanation.
Do not credit descriptive points already credited in part (a).
Description should highlight the marked contrast in precipitation totals, seasonal distribution
and number of days between a very dry north (Gao with only 200 mm in a hot desert climate
in Mali) and a much wetter south (Abidjan with 1700 mm in a tropical rainforest climate in
the Ivory Coast). Bobo-Dioulasso in Burkina Faso in central West Africa has an „inbetween‟ amount of both rain days and total annual precipitation (1000 mm in a Savannah
climate).
Candidates should also refer to the variation in rain days and seasonal distribution for each
station. Gao with a limited amount of precipitation in summer, Bobo-Doiulasso with a clear
wet season/dry season regime and Abidjan with a „twin-peak‟ regime with a major peak in
June and a smaller peak in October/November.
Explanation should focus on the role of the ITCZ and the movement of the Maritime
Tropical and Continental Tropical air masses over the course of the year. For example,
Abidjan, on the Gulf of Guinea coast, is influenced by hot, humid mT air for most of the year,
accounting for its higher total annual precipitation and greater number of rain days. The twin
precipitation peaks can be attributed to the ITCZ moving northwards in the early part of the
year and then southwards later in the year in line with the thermal equator/overhead sun.
Gao, on the other hand, is under the influence of hot, dry cT air for most of the year and
therefore has far fewer rain days and a very low total annual precipitation figure as it lies well
to the north of the ITCZ for most of the year. Bobo-Dioulasso again is in an „in-between‟
position, getting more rain days and heavy summer precipitation from June-August when the
ITCZ is furthest north.
2004
a) Given you a model answer for this question in your notes. (Hadley cell, Ferrell, polar)
b) Study the diagram. For either the Pacific Ocean or the Atlantic Ocean, explain how
the ocean currents operate to maintain the energy balance.
The question seeks an explanation of how the currents help to maintain an energy balance
and so reference has to be made to the transfer of warm water Polewards and the transfer of
cold water towards the equator.
1. The surface ocean currents directly respond to the prevailing global pattern of winds
e.g. trade winds and westerlies. Westerlies help to direct the Gulf stream/North
Atlantic drift to NW Europe. NE/SE trade winds blow equatorwards and help to guide
the westerly flowing North and South equatorial currents.
2. The Earth’s rotation and coriolis force encourage the surface currents, like winds, to
move towards the right in the N. Hemisphere  clockwise gyres in N. Atlantic and N.
Pacific. In S. Hemisphere  anticlockwise.
3. Land masses block and direct movement of currents.
4. Temperature differences  density of water. Cold water sinks and warm water rises.
Cold water displaces the less dense, surface waters.
Answers should clearly deal with the chosen ocean:
For the Atlantic Ocean:
In the Northern Hemisphere a clockwise loop or gyre is formed – with warm water from the
Gulf of Mexico (Gulf Stream/North Atlantic Drift) travelling northwards and colder water
moving southwards eg the Canaries Current. In addition cold water moves southwards from
Polar latitudes – the Labrador Current. This movement of warm and cold water thus helps to
maintain the energy balance.
Assess out of 3, with a maximum of 2 if there is no reference to explanation. Award up to 1
mark for correctly named ocean currents.