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1) Solar radiation ( SUMMARY ); 2) A simple earth energy balance model

1) Solar radiation ( SUMMARY ); 2) A simple earth energy balance model. theta. abc to solar energy. 1) Calculate the power per unit area or I ;. 2) The total power P and energy generated E(in) over time t;.

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1) Solar radiation ( SUMMARY ); 2) A simple earth energy balance model

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  1. 1) Solar radiation (SUMMARY);2) A simple earth energy balance model

  2. theta abc to solar energy 1) Calculate the power per unit area or I; 2) The total power P and energy generated E(in) over time t; 3) How long (t’) can the energy be used to power a device (a light or an electric fan etc) with P(out) Watts?

  3. I (power per unit area) versus distance P http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html

  4. Q1 • Mastering physics problems are • too easy; • 2) too difficult; • 3) ok.

  5. Q2 Tutorial problems, I have been able to work out • Less than 30% of them; 2) 30% - 60%; • 60% - 80%; • more than 80%.

  6. Power of theincomingradiation Pin = (1-A) S π REarth2 Example from Roland B. Stull, Meteorology for Scientist and Engineers

  7. Radiation of the Earth • Pout = σSurface TEarth4 Surface = 4 π REarth2

  8. Earth Energy Balance Equation A Simple model:Pin = Pout Pin = (1-A) S π REarth2 Pout = 4π REarth2 σ TEarth4

  9. Q1 T4Earth= (1-A) S /4 σ = (1- 0.3) 1367W/m2/(4∙5.67∙10-8W/m2K4) The earth temperature according to this model is • -100 C; • -18 C; • 30 C; • 100C.

  10. So we actually obtained a temperature of the Earth as seen from far away – the temperature of the atmosphere, not the surface temperature!! • What are the effects of atmosphere ??

  11. Atmospheric Absorption 1 0 • From: http://www.everythingweather.com/atmospheric-radiation/absorption.shtml

  12. Earth Energy Budget Sheet

  13. Atmospheric Absorption • From: http://www.everythingweather.com/atmospheric-radiation/absorption.shtml

  14. Green house effect • Model one: Glass layer effects on the earth temperature; • 2) Atmospheric model with Green house effect • (with Green house gases).

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