NCEA Level 3 Earth and Space Science 91414 (3.5) – Page 1 of 6

Sample Assessment Schedule

Earth and Space Science 91414 (3.5): Demonstrate understanding of processes in the atmosphere system

Assessment Criteria

Achievement / Achievement with Merit / Achievement with Excellence /
Demonstrate understanding involves explaining processes and links within the atmosphere system. / Demonstrate in-depth understanding involves explaining links between the processes in the atmosphere system. / Demonstrate comprehensive understanding involves discussing the complexity of the atmosphere system.

Evidence Statement

Q / Evidence / Achievement / Achievement with Merit / Achievement with Excellence
ONE / This is an example of a volcanically-induced climate cooling event. Tambora erupted large quantities of aerosols into the atmosphere. This aerosol layer led to the drop in temperature worldwide.
The stratospheric sulfate aerosol layer which plays a large role in modulating the net incoming radiation is strongly influenced by volcanic sulfide released from magma.
Climatic effects appear to result if the eruption is powerful enough to inject material into the stratosphere, or if the eruption is of sufficient duration that a higher-than-normal level of tropospheric aerosols is maintained.
Winds in the stratosphere spread the aerosols until they practically cover the globe. Once formed, these aerosols stay in the stratosphere for about two years. They reflect sunlight, reducing the amount of energy reaching the lower atmosphere and the Earth's surface, cooling them.

http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html / Explains the effect of matter / aerosols in the atmosphere on surface temperature over time. / Explains in depth how the aerosols from volcanic eruptions, particularly sulfides, reduce the temperature across the earth’s surface over time. / Comprehensive discussion of how aerosols from volcanic eruptions, particularly sulfides, affect radiation and result in the decrease in surface temperature of the earth.
NØ
No response, no relevant evidence. / N1
The atmosphere affects sunlight reaching the earth.
Note: Not volcanoes cause cooling – this is in the question. / N2
Aerosols are in the upper atmosphere or they reflect / block the sun. / A3
Explanation given is correct but distance (earth’s surface) and / or time is not referred to. / A4
Correct explanation including reference to distance (Earth’s surface) and time. / M5
In-depth explanation, but lacks minor detail(s) / M6
Nature (size or length) of the eruption(s) and character (sulphide) referred to in explanation. / E7
Comprehensive discussion but lacks minor detail(s). / E8
Comprehensive discussion addresses the atmospheric characteristics leading to cooling of the Earth’s surface as in Evidence.
Diagram not essential, but likely to be present to support answer.
TWO / The Hadley cell is a closed convection loop that begins to rise (creating a low pressure area) at the equator due to the air being warm and moist. It moves outward towards the poles. At approx. 30° N or S latitude it descends, creating a high pressure area. Some of the descending air travels along the surface creating the trade winds.
The Polar cell is similar to the Hadley cell but occurs at the 60th parallel. The warm air rises at this latitude and moves towards the poles. When the air reaches the polar areas it has cooled and descends as cold high pressure areas. The air then moves away from the poles along the surface to produce the Polar easterlies.
Both the Polar and Hadley cells are a result of surface temperatures. They are also very stable and are not affected by passing weather systems.
The Ferrel cell is a secondary convection feature that is dependent on the Hadley and Polar cells for its existence. The Ferrel cell is a result of interaction between the high and low pressure areas at the mid-latitudes. It results in the (prevailing) Westerlies.
The Ferrel cell is not a true closed convection loop like the Hadley or Polar cell and can be affected by passing weather systems.

http://www.geology.wmich.edu/kominz/images1/ATM_Convection%20MAK.jpg / Explanation of three convection cells and an outline of the processes they involve. / Explanation of how the three convection cells work and how they are related to each other / Comparison of the three convection cells, their interaction and the effects on the atmosphere explained in depth.
NØ
No response, no relevant evidence. / N1
The idea of convection correctly described. / N2
ONE cell briefly explained / A3
TWO of THREE cells briefly explained / A4
All THREE cells briefly explained. / M5
TWO cells explained in terms of convection and their link(s) explained. / M6
All THREE cells explained in terms of convection and their link(s) explained. / E7
Interaction(s) of THREE cells explained in depth. One cell may be less clearly explained or an interaction may be less clear. / E8
Interaction(s) of all THREE cells explained in depth.
THREE / Sunlight (heat energy) passes through the atmosphere to the surface of the Earth. Normally much of this heat energy is radiated back towards space. However, in the case of global warming, the outgoing heat is absorbed by certain gases in the atmosphere. This blocks some heat from escaping the atmosphere, thus resulting in an increase in global temperature.
Gases that contribute to the greenhouse effect include:
·  Water vapour. The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate. Water vapour increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.
·  Carbon dioxide (CO2). A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions, and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by a third since the Industrial Revolution began. This is the most important long-lived ‘forcing’ of climate change.
·  Methane. A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, and ruminant digestion and manure management associated with domestic livestock. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one that is much less abundant in the atmosphere.
·  Nitrous oxide. A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
·  Chlorofluorocarbons (CFCs). Synthetic compounds of entirely industrial origin used in a number of applications. Now largely restricted in production and release to the atmosphere, by international agreement, because of their ability to contribute to destruction of the ozone layer. They are also greenhouse gases.
As the amount of these gases increases in the atmosphere the amount of heat energy that gets trapped increases. This is what leads to the increase in global temperature. / Explains what happens when sunlight (heat energy) arrives at the atmosphere, and how this changes when greenhouse gases are present in the atmosphere because of the insulating effect. / Explains causes of global warming including explanation of origins and impact of greenhouse gases. / Discusses causes of global warming, including explanation of origins and impact of greenhouse gases.
Evidence for the overall effect on the earth over time is explained.
NØ
No response, no relevant evidence. / N1
Role of atmosphere in temperature control given.
Note: gases contributing to greenhouse effect are given in the question. / N2
General idea of global warming given. / A3
Answer at Achievement level but some details unclear. / A4
Full answer at Achievement level. / M5
Answer at Merit level but detail about only ONE or TWO gases given. / M6
Full answer at Merit level referring to MORE THAN TWO of the gases named in question. / E7
Full discussion of global warming with some supporting details showing comprehensive understanding. / E8
Full discussion of global warming with supporting details showing comprehensive understanding.