From few colors come many shades
You have six crayons: red, yellow, blue, green, black and white. Does this mean you cannot draw a pink flower or an orange sunset? Certainly not. A little white with your red will give you pink. And yellow with red gives you orange. The black and white together will give you every possible shade of gray. The possibilities are endless.
In a similar way, a few bits of information can be combined to create important new information. With the help of computers, scientists do this mixing quite a lot.
A satellite being built now, called GOES-R, will produce many types of information that can be used to create lots of other information. (GOESR stands for Geostationary Operational Environmental Satellite, Series R.) One of six instruments on this new weather satellite is the Advanced Baseline Imager.
This imager captures 16 different images at a time of the same scene. To do this, it separates the colors of light from the scene into 16 different slices. You can think of a “slice of light” as being like a crayon of a certain color. In this case, there are 16 crayons, not just six. (See the illustration.) Some of these slices of light are not even visible to us.
Why does the GOES- R imager slice up the light like this?
Different materials reflect more of certain slices of sunlight than others. (Scientists call these slices “wavelengths” or “ranges of wavelengths.”) For example, to our eyes, snow and clouds would look similar from space. But a sensitive imaging instrument can see a tiny difference.
Using a special computer program, scientists look at images in only the first six slices of the 16 “ slices of light.” In this case, these are the slices that best reveal what is snow and what is cloud. From the computer program’s output, the scientist can then report to someone such as a water resource manager exactly how much of the ground is actually covered with snow. The water manager will then know how much fresh, clean water to expect from the melting snow in the spring.
What other interesting “crayons” does GOES-R have? Play “Satellite Insight,” a fun game with colorful pretend data from GOES- R. Go to http://spaceplace.nasa.gov/s atellite-insight/.
THIS ARTICLE was written by Diane K. Fisher and provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.