Sub-synoptic-scale IR (10.7 um)
The corresponding sub-synoptic-scale 10.7 um image, as was seen in the large-scale example, provides estimates of cloud and surface skin temperatures. A forecaster can use cloud top brightness temperature to compare with a local sounding to get an estimate of cloud top height. This estimate works best for thick clouds; it should not be used for thin clouds since the signal received by the satellite for thin clouds is a combination of radiance from below the cloud as well as from the cloud, resulting in a brightness temperature that is warmer than the actual temperature of the cloud.
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| 10.7 um Image |
The small, light blue region of clouds in the thunderstorm in eastern CO can be used as an example. This particular color matches a brightness temperature of -44C, as seen on the color bar at the bottom of the image. When compared with the 1200 UTC sounding from Denver, CO, this temperature corresponds to a height of 300 mb, roughly 30,000 ft (10,000 m). Remember that thick cirrus can be distinguished from thin cirrus by using the fog product (about which more later), or by using a combination of the water vapor imagery and the 10.7 um imagery.
