Local Satellite

What is the Difference Between Visible and Infrared Satellite?

Visible Satellite

Visible satellite images can be thought of as photographs of the earth from space. Since they are like a photograph, they are dependent on visible light (brought by the sun). As a result, visible satellite pictures only work during daylight hours. This is the greatest drawback to using visible imagery. Also, since a visible satellite picture is basically a photograph, thicker clouds (which reflect the most sunlight) show up very bright, while thinner clouds (like cirrus) are hard to distinguish.

Infrared Satellite

Infrared satellite technology works by sensing the temperature of infrared radiation being emitted into space from the earth and its atmosphere. Basically, all objects (including water, land, and clouds ), radiate infrared light. However, our eyes are not "tuned" to see this kind of light, so we don't notice it. Weather satellites not only sense this infrared light, but they can also sense the temperature of the infrared emissions. The warmest emissions are displayed as dark greys on an infrared satellite image, while cold emissions are displayed as bright white (or sometimes other colors of the rainbow). In general, the temperature of the atmosphere decreases with height. Since clouds are often high in the atmosphere (about 10,000 feet), they are in air that is much colder than the earth's surface. Therefore, the rule of thumb is: the brighter the cloud in an infrared image, the higher the cloud. However, there are two major drawbacks to infrared satellite pictures. One, low clouds are almost impossible to spot since they blend in with the ground (remember, the image is based on relative temperatures... Low clouds are about the same temperature as the ground). And two, the resolution of the images is much lower. When zooming into an infrared picture, the image will look "blocky" much sooner.

  Visible Infrared
Usable when? only during daylight hours all the time
High clouds appear as not distinguishable from low clouds bright white
Low clouds appear as not distinguishable from high clouds very dark, sometimes blending in with the ground
Thin clouds appear as milky white not distinguishable from thick clouds
Thick clouds appear as bright white not distinguishable from thin clouds
Resolution of cloud pixels 1 km (high resolution) 4 km (lower resolution)

Back to satellite image

Copyright © 2016 The Weather Underground, Inc.















  Today is Friday, May 27, the 148th day of 2016. There are 218 days left in the year.
1866 -- 150 years ago: We understand that several young gentlemen of this city have formed a baseball club, and we soon may expect to witness the skill of those who practice this healthful and invigorating game.
1891 -- 125 years ago: Students at Augustana College presented a handsome gift to O.M. Benson, who was forced to resign from his position of instructor because of illness.
1916 -- 100 years ago: The auto of F.M. Carpenter was damaged badly when it struck a streetcar on Fort Armstrong Avenue near the curve.
1941 -- 75 years ago: Lewis B. Wilson, president of the State Bank of Rock Island, was elected treasurer of the Illinois Banker's Association.
1966 -- 50 years ago: Corn hasn't sprouted yet in Iowa, but it stood pretty high last night on the stage of the RKO Orpheum. The Jimmy Dean show may be pure corn, but 5,600 persons jammed the theater to capacity as the 37-year-old Texas television star made his second appearance in the Quad cities.
1991 -- 25 years ago: United Auto Workers at the Case IH East Moline plant accepted contract changes Sunday that guarantee their unemployment payments during plant shift downs and that lead to new health care programs.