ALBEDO
The proportion of incoming radiation (solar energy) that is reflected by a surface is called its ___________________. Why is the Albedo effect important?
The more radiation reflected the less global warming that occurs. You now should know how the ice caps reflect solar radiation and hence why their melting is such a big issue.
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Earth & Space Science: Climate Change
Albedo Worksheet:
Please fill in the missing words below: Energy from the sun, called ____________________, is either absorbed by the Earth’s surface or reflected back into the atmosphere. The amount of solar radiation that is reflected from a surface is called ­ ­ ­_________________. Snow covered surfaces, such as the polar ice caps, reflect between 80‐90% of light energy away from their surface and therefore have a _________________ albedo. Darker coloured surfaces reflect less solar radiation, retain a greater amount of heat and have a _______________ albedo.
Albedo is an important concept to address when discussing _____________________ because of the increased rates of melting ____________________. At the Earth’s poles vast areas that were once highly _______________________ have been replaced by a darker coloured ocean. The dark surface then retains _______________________ heat and contributes to further melting. Scientists call this cycle a positive feedback loop because each process is encouraging the other.
Albedo can be observed on a small scale: you may have noticed how hot it feels when you wear a black shirt in the sun compared to a cooler white shirt. A dark shirt would have a _________________albedo where a white shirt would have a ____________________ albedo. In addition to the increased rates of melting caused by climate change, human activity has influenced the Earth’s albedo through land use changes such as urban development, conversion of forests to farmland, and deforestation.
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Where we get our ENERGY
Life on Earth depends on energy coming from the sun. About half the light reaching Earth's atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. How much of the suns energy is absorbed by the earth's surface? (see diagram)
70 % of the solar energy is absorbed by the earth’s atmosphere, water and land. Why is this happening? Different parts of the earth’s surface receives different amounts of solar energy. Tilt and orbit
Balancing: the heat absorbed at lower latitudes is balanced by that which is returned to space via thermal radiation north of 40 degrees latitude. This balance is affected by changes in the earth's albedo. 4
Thermal Energy & Heat Sinks
Heat sinks: any substance that can absorb and store thermal energy (heat) with little change in temperature, such as the ocean and great lakes. Ex. Swimming pool in the summer; when your body sweats, the water absorbs and stores thermal energy and then evaporates cooling your body.
Water vapour in the atmosphere (clouds are condensed water vapour) are able to absorb and hold thermal energy. Is land a good heat sink? Why or why not? Thermal energy: is the energy associated with the temperature of a substance and changes of state. The thermal energy leaves the sun in the form of radiation called heat.
Heat is thermal energy in transfer.
When you put your hand over a hot stove you can feel the heat. You are feeling thermal energy in transfer. The atoms and molecules in the metal of the burner are moving very rapidly because the electrical energy from the wall outlet has increased the thermal energy in the burner. We all know what happens when we rub our hands together. Our mechanical energy increases the thermal energy content of the atoms in our hands and skin. We then feel the consequence of this ­ heat.
The volume expansion in a gas occurs due to both temperature and pressure. 5
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