False-Color Images |
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Remote sensing scientists measure a broader spectrum of electromagnetic radiation than visible light alone to observe and quantify changes on the Earth’s surface. For fires and burned areas, infrared light, which has a longer wavelength than visible light, can penetrate smoke and reveal information about vegetation. The above image combines near-infrared, red, and green wavelengths as red, green, and blue, respectively. Vegetation strongly reflects near-infrared radiation, so intact forest and fields appear red. Bare ground, like the dry areas surrounding the shore of the two reservoirs in this image, strongly reflects both near-infrared and visible light, so it appears light colored. Burned areas, on the other hand, absorb all three wavelengths, so these areas appear relatively dark. Landsat 7 acquired these data on June 30, 2002. (Image by Robert Simmon, NASA GSFC, based on data provided by Andrew Orlemann, USDAFS) |
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This scene combines shortwave-infrared, near-infrared, and green light as red, green, and blue, respectively. The near-infrared light reflected by plants makes forests and fields appear green. Burned areas absorb green and near-infrared light, but reflect shortwave-infrared light, so they are red colored. Only green wavelengths (the blue channel of this image) are blocked by smoke particles, so the smoky haze is tinted blue. Landsat 7 acquired these data on June 30, 2002. (Image by Robert Simmon, NASA GSFC, based on data provided by Andrew Orlemann, USDAFS) |
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