Satellite Smoke Plumes Over the U.S.
November 06, 2007
Though wildfire smoke plumes can cover huge areas affecting hundreds of thousands of people (or more) in downwind areas, they're sometimes too subtle to be detected on single-channel, visible or infrared satellite images. However, multispectral images from weather satellites can highlight smoke by combining visible and near infrared together with short-, mid-, and long-wave infrared channels to enhance the contrast between smoke and its surroundings. In addition, sometimes these spaceborne images show features that aren't normally visible in routine imagery. The August 14, 2007 images from the U.S. National Oceanic & Atmospheric Administration (NOAA) satellites are shown above. NOAA 17 (top) and NOAA 18 (bottom) show two different types of smoke signatures. In the image on the left, smoke is highlighted as a semi-transparent gray arc from Minnesota through Wisconsin and Iowa. On the right, a different combination of channels shows the same views with smoke standing out in sharper contrast with a more opaque appearance. The images on the right also show areas of haze in Missouri and the southeast U.S., which was not expected and not really evident from the images on the left.