Energy Flashcards
Define Radiation
energy that travels in the form of electromagnetic waves
How is radiation emitted by Earth different than radiation emitted by the Sun?
- Earth: longwave radiation
- Sun: shortwave radiation, sun emits more radiation
What causes scattering and reflection of SW Radn?
- Gases
- Aerosols (dust, sea salt, smoke)
- Clouds
Why is the sky blue?
The gas molecules in the atmosphere scatter blue light
Define “Albedo”
-the proportion % of SW radn energy scattered upward by a surface
High Albedo
-Reflects a lot of the suns radn
Examples of High Albedo
1) Snow & Ice
2) Clouds
3) Deserts
4) Water
Low Albedo
-absorbs a lot of the suns radn
Examples of Low Albedo
1) Forests
2) Water
3) Earth & Atmosphere
4) Moon
How are clouds like umbrellas?
-clouds cool earth by reflecting SW radn back into astmos
=negative feedback effect
How are clouds like blankets?
-clouds warm earth by absorbing LW radn and emitting it back to the earth’s surface
=positive feedback effect
Is the atmosphere better at absorbing LW or SW radn?
-Long Wave radn.
=greenhouse effect
what effect do low thick clouds have?
- net cooling affect
- low clouds have higher albedos
What effect do high clouds have?
-net warming effect
What is the “Greenhouse Effect”?
Accumulation of heat in the lower atmosphere through the absorption of long wave radiation from the Earth’s Surface
what does the earth’s surface gain radiation from? 2 sources
1) Sun
2) Atmosphere
What strengthens the GHE?
1) Clouds (umbrella vs. blanket)
2) Human Activity
Explain how the greenhouse effect operates.
1) Earth’s surface=absorbs the suns radiation (SW), and emits longwave radiation.
2) Atmos= absorbs most of the LW from the earth’s surface in clouds and greenhouse gases.
3) Atmosphere=emits LW radiation back to the surface to be absorbed, and up into space.
What is heat transfer?
=energy in the process of being transferred btw. objects of diff. temps
-high temp–>low temp
What are the 3 methods of heat transfer?
1) Conduction (solids)
2) Convection (liquids + gases)
3) Radiation (electro. waves)
How does Conduction transfers heat away from Earth’s surface
=by a transfer of energy from one molecule to the next, causing a decrease in temperature.
How does Convection transfers heat away from Earth’s surface
=when a fluid is heated by a warm surface, expands, and rises creating an upward flow
How does Radiation transfers heat away from Earth’s surface
=by emitting long wave radiation into the atmosphere
