Reflectivity

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what is the reflectivity of the tundra? Very Happy

Joined: 23 Mar 2004 Posts: 74 Location: Barrow, AK

Mitchell
When you say "what is the reflectivity of the tundra?" I am not sure if you mean to ask what reflectivity is in general, or what were the actual reflectivity numbers that we measured. I will try to answer both.

Reflectivity is the ratio of the light that is reflected from a surface to the total amount of light that is hitting the surface (called incident light). Remember that light is composed of many different wavelengths, not all of them visible. You can measure total reflectivity of many wavelengths or a specific reflectivity at one wavelength. When we measured the reflectivity of the tundra with the UniSpec, we measured in a range of wavelenths from about 300 nm to 1100 nm, which covers the visible and infrared light range.

The tundra tended to absorb (and thus NOT reflect) wavelengths in the blue and red range. It reflected light in the green wavelengths and a lot more in the near infrared and infrared ranges. This information was used to calculate the NDVI, or Normalized Difference Vegetation Index, which can be used to compare the amount of vegetation in different places and is used with satellites quite often.

Here is a picture of the tundra reflectivity curve at the range of wavelengths which we measured:
http://archive.arcus.org/TREC/phpbb/album_pic.php?pic_id=1102

Let me know if you have any other questions!
Mrs. N-O