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Energy Released by the Earth Now that you have read about factors influencing the solar energy being absorbed by the Earth, let's look at the other side of the Energy Balancing Act - The energy released/or emitted by the Earth. To account for the energy released by the Earth, we will look at three influential factors: Surface Area, Temperature, Emissivity.
SURFACE AREA Picture the heated Earth radiating energy out in all directions. If you were to choose a geometric figure to represent your emitting energy source, what would it be? 
TEMPERATURE Many factors affect the temperature of the Earth. Scientists can use the Stefan-Boltzman Equation This equation relates the amount of longwave radiation emitted to the temperature of the object, given that the object is a "black body" E = (s)(T4 ) (temperature is in Kelvin) Would you say that the longwave energy emitted is directly or inversely proportional to temperature? Therefore, as the surface temperature of Earth increases, what happens to the longwave radiation it emits? (increases or decreases) Notice the power of 4 in the equation above. If you were to graph the Stefan-Boltzman equation, what type of graph would you expect to see and why? (If you are uncertain, substitute a few values and see what pattern emerges? Absolute temperature is used : oC + 273 = K As of right now, our tutorial has presented surface area and temperature as factors that influence the amount of longwave radiation emitted from the surface of the Earth. If all the energy emitted by planet Earth was radiated out to space, our planet's temperature would be much lower than it actually is. It would be about 255K, instead of its actual 280K. What "traps" , "absorbs", "re-emits" some of this longwave radiation? page 5 |
