Surprise Optional Assignment Answers                            

1.   Nitrogen and oxygen in the air are c. (transparent to VIS light). Oxygen and ozone make the atmosphere a. (opaque to UV light).   Water vapor and carbon dioxide b. (selectively absorb IR light).
      a. opaque to UV light         b. selectively absorb IR light         c. transparent to VIS light.

2.    Atmospheric windows are found in the a. VIS and d. far IR (centered at 10μm)  portions of the electromagnetic spectrum.
       a. VIS          b. UV         c. near IR          d. far IR
3.    You look through a pair of sunglasses and everything looks green.  Which of the absorption curves below  would best describe this behavior?  (green light has 0.5 micrometers wavelength.
The curve on the right transmits green light




4.     In the figure at right 3 units of sunlight arrive at the earth.  1 arrow of sunlight is absorbed in the atmosphere, the other 2 pass through the atmosphere and get absorbed by the ground.  The ground emits 4 arrows of IR radiation.  2 arrows pass through the atmosphere and go into space and 2 are absorbed by greenhouse gases in the atmosphere.  To be in energy balance the atmosphere must emit 1 arrow of IR radiation upward into space and 2 arrows of IR radiation downward toward the ground.


5.     The largest fraction of the sunlight that arrives at the earth c. passes through the atmosphere and gets absorbed at the surface (about 50%).  The next greatest amount d. is reflected back into space (about 30%).
       (you should consult the figure on p. 71 in the photocopied notes to answer this question)
        a. is absorbed in the atmosphere by greenhouse gases
        b. is absorbed in the atmosphere by oxygen and ozone
        c. passes through the atmosphere and gets absorbed at the surface
        d. is reflected back into space

6.     Which of the following are true?
        (consult the confusing figure on p. 72 in the photocopied notes to answer this question)
        a. most of the IR radiation emitted by the earth passes through the atmosphere and travels into space
        b. the earth emits more energy than it receives from the sun
        c. there is more IR energy from the atmosphere arriving at the earth's surface than there is sunlight
        d. the atmosphere emits equal amounts of energy upward into space and downward toward the ground