The Infrared Channel: Clouds on IR Imagery

Clouds on IR Imagery

Infrared imagery, like visible, can be used to analyze thunderstorms, mid-latitude systems (comma cloud), and hurricanes (eye) as you can see in the image (lower left). Cloud-top temperatures, like surface-feature temperatures, can be determined using IR imagery. You can tell the difference between low and high clouds in the IR imagery because they have different cloud-top temperatures. High altitude clouds have colder cloud-top temperatures than lower altitude clouds as shown below right. Scroll down for more information.

Cloud-top Temperatures As a Function of Cloud Height

Low Cloud/Fog and Surface Temperature Similarity
Look at the graphic to the left. When very low clouds (like fog) have a cloud-top temperature approximating the surrounding surface temperature, it becomes difficult for a user to distinguish low clouds from the surface. Low clouds and the surface may be indistinguishable in IR imagery. In this case, VIS imagery may be more useful in identifying low clouds or fog, when it is available.


	Look at the graphic to the left. When very low clouds (like fog) have a cloud-top temperature approximating the surrounding surface temperature, it becomes difficult for a user to distinguish low clouds from the surface. Low clouds and the surface may be indistinguishable in IR imagery. In this case, VIS imagery may be more useful in identifying low clouds or fog, when it is available.