SAMPLE PAPER
3
Level 3 Earth and Space Science
3.5: Demonstrate understanding of processes in the
atmosphere system
Credits: Four
Check that you have completed ALL parts of the box at the top of this page.
You should answer ALL parts of ALL questions in this booklet.
If you need more room for any answer, use the space provided at the back of this booklet.
Check that this booklet has pages 2–9 in the correct order and that none of these pages is blank.
YOU MUST HAND THIS BOOKLET TO YOUR TEACHER AT THE END OF THE ALLOTTED TIME.
EXEMPLAR FOR EXCELLENCE
NOTE: These exemplars do not fully show Grade Score Marking (GSM) because
of the small sample of student scripts involved, and the absence of a cut score
meeting to determine
grade
boundaries.
GSM can be seen in the level 1 and level 2
OVERALL
LEVEL
OF PERFORMANCE
exemplars from the 2012 examinations, which will be published on the NZQA website
when the assessment schedules are published.
© New Zealand Qualifications Authority, 2012
All rights reserved. No part of this publication may be reproduced by any means without the prior permission of the New Zealand Qualifications Authority.
2
You are advised to spend 60 minutes answering the questions in this booklet.
QUESTION ONE: VOLCANIC ERUPTIONS
Some major volcanic eruptions can lead to temperature changes worldwide. An example of this
occurred in 1816 when the world experienced ‘the year without a summer’. It was a result of the
large volcanic eruption of Tambora, Indonesia, in 1815.
Discuss the reasons why the Tambora eruption of 1815 resulted in cooler temperatures worldwide
in 1816.
Your answer should include:
• effect of aerosols in the atmosphere
• transport of matter in the atmosphere
• transport of heat in the atmosphere.
A diagram may assist your answer.
Normally the solar energy penetrates the earth’s atmosphere, resulting in heating of the
surface of the earth. Some of this radiation is absorbed and some is reflected. When
Tambora erupted in 1815 large volumes of ash and gases (aerosols) were ejected into the
atmosphere. Because the eruption was powerful it went through the troposphere and into the
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stratosphere. Once in the stratosphere the winds move the aerosols around the globe over
time.
The aerosols act as a barrier to the incoming solar radiation. They reflect most of the solar
radiation back into space, which means less radiation makes it to the surface. This results in
cooler temperature worldwide.
Eruptions with high levels of sulphur are more likely to affect temperature because the
compounds reflect the radiation better.
The eruption occurred in 1815, yet the cooler temperatures were worldwide in 1816. This is
because the aerosol in the stratosphere took a long time to be distributed worldwide.
Therefore the global drop in temperature wasn’t immediate. The aerosols once circulated
stay in the stratosphere for some time, often for years and years.
‘The year without a summer’ happened because the aerosols remained in the atmosphere, and
the surface of the earth was not able to warm up.
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QUESTION TWO: CONVECTION CELLS
There are three main convection cells found in the earth’s atmosphere. The three main cells are
Hadley, Ferrel and Polar.
Compare and contrast the three main convection cells and their effects on the earth’s atmosphere.
Your answer should include:
• a description of the three main types of cells
• explanation of how heat energy is transported by these cells
• effects on the atmosphere.
A diagram may assist your answer.
The Hadley cell is a closed circulation loop in the atmosphere, which originates at the
equator. In this region there is a lack of surface winds, which are referred to as the
Doldrums. At the equator the air is warm and moist and this air moves up and out towards the
poles. The warm air rises because it is less dense, has fewer particles in a set volume. The
rising air at the equator creates a low pressure area. At approx. 30° latitude north or south
this moving air descends creating a high pressure area. The cool air descends because it has
become denser. The air that did not rise travels along the surface creating the trade winds.
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Movement of air in the Polar cell has a similar action to the Hadley cell, but occurs at the
60th parallel. Here the warm air rises at approx. 60° and moves towards the poles. When the
air reaches the polar areas it cools and descends, creating a high pressure area. The air
moves away from the poles along the surface to produce the Polar easterlies.
The Ferrel cell is a secondary circulation feature and is dependent on both the Hadley and
Polar cells. It results from the mixing of high and low pressure areas at the mid-latitudes,
resulting in the prevailing westerlies.
Both the Hadley and Polar cells are a result of the surface temperature and are very stable
because they are not affected by passing weather systems. However, the Ferrel cell is
affected by passing weather systems. The Polar and Hadley cells are both closed circulation
loops but the Ferrel cell is not. While the three cells act at different latitudes they are all
responsible for the major winds of the earth.
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QUESTION THREE: GLOBAL WARMING
The main greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, and
chlorofluorocarbons. Global warming shows that the Earth’s average temperature has increased
by approx. 0.8°C in the last 100 years.
Discuss the reasons for this increase in global temperature.
Your answer should include:
• transport of heat in the atmosphere
• reasons that greenhouse gases have changed over time
• global temperature change.
• the role of water vapour as a feedback mechanism.
A diagram may assist your answer.
100 yrs ago
Now
Water vapour as a positive feedback Normally solar radiation penetrates the atmosphere to the surface of the Earth where some
is absorbed and some is reflected back to space. In global warming some of the outgoing heat
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is absorbed and reflected by certain gases in the atmosphere, thus trapping the heat
(preventing it from going back to space) leading to an increase in global temperatures.
The major gases are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and water
vapour.
Carbon dioxide is normally found in the atmosphere as it is released during the process of
respiration and volcanic eruptions. It is also released from human activities such as
deforestation, land use changes and burning fossil fuels. These human activities have
increased dramatically the concentration of carbon dioxide in the atmosphere because they
either increase carbon dioxide emissions or they have decreased the recycling of carbon
dioxide from the atmosphere in the carbon cycle.
Methane is a hydrocarbon gas that is produced from natural sources such as decomposition
of organic waste material and agriculture. Human activity has increased the concentration of
methane due to greater decomposition from waste and landfill and increased agriculture. The
main reason this has increased over time is due to the larger population on Earth.
Nitrous oxide is a powerful greenhouse gas that is produced by soil cultivation practices;
especially the use of commercial and organic fertilisers, fossil fuel combustion in engines,
nitric acid production, and biomass burning. All of these result from human activity, which
has increased over time.
Chlorofluorocarbons (CFC) are synthetic compounds previously used in a variety of application
such as refrigerant, expander for styrene to produce polystyrene and as a propellant in
aerosols. These days most of the uses have been discontinued by international agreement and
their production limited. Even though the use of CFCs has markedly dropped it is still a major
factor because the gases are long lived in the atmosphere and some are still entering the
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atmosphere from landfills (release of refrigerant from old freezing systems and the eventual
breakdown of polystyrene).
As the amount of these gases increases in the atmosphere the amount of heat energy
trapped increases. This increased depth of the gases in the atmosphere, acts as an insulating
layer that prevents heat energy radiating out to space, thus leading to an increase in global
temperature: as seen by the 0.8o rise in the last 100 years.
Water vapour concentration has also increased due to increased human population and
increased fossil fuel combustion. Water vapour acts a positive feedback to the climate. This
means that as the water vapour concentration increases the temperature will also increase.
The increase in temperature due to all the increased greenhouse gases means the
atmosphere can hold more water vapour, which will therefore increase the temperature even
further in a cyclic nature.
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Extra space if required.
Clearly number the question (if applicable).
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Extra space if required.
Clearly number the question (if applicable).
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