Purpose:

The purpose of this activity is to enable the students to understand the effects that the atmosphere has on incoming radiation. This understanding then can be used to explain the atmospheres effect on images gathered by remote sensing.

Materials:

none

About this Activity:

This activity involves classroom discussion and students' interpretation of a graph.

Procedure:

1. The electromagnetic energy travels through the atmosphere from the sun to target remote sensing sensors. These sensors pick up visible and infrared radiation. Each wavelength belongs to a characteristic band, which is just a range of wavelengths. Each band can be described by a color, like blue, if the observed wavelength is within a certain range of visible light. If not visible light, then the band is described by other wavelengths in the electromagnetic spectrum, like infrared.

   Bands	Wavelengths
   1	blue
   2	green
   3	red
   4	near infrared
   5	near infrared
   6	thermal infrared
   7	near infrared

   Questions related to the atmospheres "absorption, transmission and scattering of energy:"

   1. Ask: Which type of energy do you think passes through the atmosphere and reaches the sensor directly (unaltered)? Why? (transmitted energy)
   2. Ask: When energy is absorbed, explain the type of radiation that is re-emitted. Why? (Absorbed energy warms the atmosphere and has a longer wavelength.)
   3. Ask: What effect do you think atmospheric scattering does to the image being scanned? (It results in haze and diminished image clarity.) Scattering- the redirection of light by particles or molecules in the atmosphere.
   4. Draw the following graph on the board and have students write down their interpretations from the graph.

   

   Key:

   B = blue

   G = green

   R = red

   IR = infrared

2. Discuss students interpretations of the graph.
3. Have students explain the effects of scattering, absorbing, and transmitting energy through the Earth's atmosphere.

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