Geosynchronous satellite imagery is used extensively in weather forecasting, for determining cloud types and patterns, and identifying the locations of certain weather features. The most commonly-used imagery are visible, infrared, and water vapor. The first detects features illuminated by the sun, while the latter two detect radiation emitted by the Earth or by the water vapor in the atmosphere. Because the temperature generally decreases upward in the atmosphere and warmer objects emit more radiation, the intensity of radiation received by the satellite can be used to infer the altitude of the emitting clouds or water vapor or the temperature of the Earth's surface.
Various combinations of these images are used to identify clouds and determine their approximate height and thickness. The cloud and water vapor patterns can be used to identify cyclones, frontal systems, outflow boundaries, and upper-level troughs and jet streams.