NOAA Geostationary Satellite Server

Western U.S. Sector Infrared (Enhancement 4)

Western U.S. Sector Infrared Enhancements

Enhancement 1 Enhancement 2 Enhancement 3 Enhancement 4 No Enhancement
Western U.S. Infrared Enhancement 1 Western U.S. Infrared Enhancement 2 Western U.S. Infrared Enhancement 3 Western U.S. Infrared Enhancement 4 Western U.S. Infrared No Enhancement


Meteorologists use color enhanced imagery as an aid in satellite interpretation. The colors enable them to easily and quickly see features which are of special interest. Usually they look for high clouds or areas with a large amount of water vapor.

In an infrared (IR) image cold clouds are high clouds, so the colors typically highlight the colder regions. The bar on the right side of the image indicates the pixel brightness values for the corresponding color. The intensity value represents emitted infrared radiation. The intensity of a pixel is recorded as a digital number (for example, in these images the numbers range from 0 to 255.) You can determine temperatures using one of the formulas below:

If B > 176, T = 418 - B; or
if B <= 176, T = 330 - (B/2)

Note that the resulting temperatures are in Kelvin. To calculate the resulting Kelvin temperature to Fahrenheit:
(K - 273.15) x 1.8 + 32.00. To calculate the resulting Kelvin temperature to Celsius: C = K - 273.

(B = Brightness value; T = Temperature; F = Fahrenheit; C = Celsius)