Global Systems and Energy Transfer -...
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Unit 4 chapter 2 notes.notebook 1 April 27, 2015 Chapter Two Global Systems and Energy Transfer
Transcript of Global Systems and Energy Transfer -...
Unit 4 chapter 2 notes.notebook
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April 27, 2015
Chapter Two
Global Systems and Energy Transfer
Unit 4 chapter 2 notes.notebook
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April 27, 2015
2.1 Energy Relationships and the Biosphere
Radiant energy refers to the energy that is transmitted as electromagnetic waves (solar energy). Solar energy has many different wavelengths which are included in the electromagnetic spectrum.
What is the relationship between energy, wavelength, and frequency?
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Insolation
Insolation is the amount of solar energy received by a region of Earth’s surface. The amount of insolation that a region gets depends on latitude (imaginary lines that run parallel to the equator) and the biosphere.
The angle of inclination is the degree by which Earth’s poles are tilted from perpendicular of the plane of its orbit (23.50). If you are tilted towards the sun you are going to have a higher insolation than if you are tilted away from the sun.
https://www.youtube.com/watch?v=vDgUmTq4a2Q
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Angle of Incidence and Insolation
Angle of incidence can affect insolation as well. The angle of incidence is the angle between a ray falling on a surface and the line of the perpendicular to that surface.
Larger angles of incidence = same radiation over larger area (polar regions) = less insolation
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What does insolation mean for temperature?
Less insolation (rays) occurs in colder temperatures which means that the higher latitudes (polar regions) are going to have a greater change in temperature throughout the year as the Earth moves away from and towards the sun. The equator will have warmer temperatures because it has more insolation than the higher latitudes.
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Albedo
Albedo refers to the percent of solar radiation that reflects.
Light colored and shiny surfaces will reflect more solar energy which means the environment will be cooler.
Dark colored and dull surfaces will absorb more solar energy which means the environment will be warmer.
Average albedo for Earth is about 30%.
Which area do you think will have the highest albedo?
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Natural Greenhouse Effect
The natural greenhouse effect is the absorption of thermal energy by the atmosphere. It keeps the temperature bearable for living organisms.
The greenhouse gases are the gases that contribute to the greenhouse effect. These gases are: water vapour, carbon dioxide, methane and nitrous oxide.
Analogy: imagine sleeping with a thin blanket during the summer.
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Net Radiation Budget
Net radiation budget is the difference between the amount of incoming radiation and of outgoing radiation reemitted from Earth’s surface and atmosphere.
Net radiation budget = incoming radiation – outgoing radiation
Two things can happen to radiation:
1) Reflection by atmosphere, clouds, and surface (30%)2) Absorption by GHG, clouds, surface, and atmosphere
(70%)
We want incoming radiation = outgoing radiation, why?
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Net Radiation Budget and Latitude
The polar regions have less incoming radiation because of albedo/insolation and more outgoing due to reflection; therefore, there is a net radiation budget deficit.
The equator has more incoming radiation because of albedo/insolation and less outgoing due to absorption; therefore, there is a net radiation budge surplus.
To maintain a healthy climate the earth's net radiation deficit and surplus must balance out.
Section Questions:Page 369 #116
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2.2 Thermal Energy Transfer in the Atmosphere
Thermal energy transfer is the movement of thermal energy from an area of high temperature to an area of low temperature. What can we connect this to?
When thermal energy is absorbed, it increases kinetic energy which results in the temperature increase which emits radiant energy (infrared radiation).
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Heat Transfer
Heat Transfers Three Ways:
1) Radiation is the emission of energy as particles or waves.
2) Conduction is the transfer of thermal energy through direct contact between particles of a substance, without moving the particles to a new location.
3) Convection is the transfer of thermal energy through the movement of particles from one location to another...usually occurs in fluids.
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Thermal Energy Transfer In Atmosphere
Atmospheric pressure is the pressure exerted by the mass of air above any point on Earth’s surface. Warm air is less dense; therefore, less atmospheric pressure.
Wind is the movement of cool air from these areas of high pressure to areas of low pressure.
Both of these play a role in the movement of thermal energy across the globe.
