On the nightly weather report you may have observed an image of the clouds from above. These images are obtained by Geostationary Operational Environmental Satellites (GOES), which are in two geostationary orbits above the eastern and western United States. Their coverage area will always include the United States, although full-earth views include other western hemisphere locations.
- These meteorological satellites provide a continuous data stream for NOAA’s National Weather Service, enabling real-time monitoring of the atmosphere. GOES is an integral component of weather forecasting.
The GOES system of satellites are capable of producing imagery on a minute-by-minute frequency in the case of severe storms. However, GOES imagery is typically produced in thirty minute intervals, throughout the day and night. Each satellite imager collects energy reflected or emitted from Earth’s surface and atmosphere. All images are created in a digital form.
- There are five basic channels or spectral bands in which GOES data are collected. Ground stations receive the digital information. The data are then displayed as the various grayscale images shown above.
The visible channel (channel 1) is a collection of reflected light in the 0.52-0.72 mm wavelength. These images are obtained only during daylight hours. They are used to show clouds,
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haze, severe storms, snow cover, volcanic activity, and other visible features. Many surface features are also apparent.
The infrared (IR) imagery represents the measurement of energy emitted by the Earth in a variety of wavelengths, the above image is a channel 2 image from the 3.78-4.03 mm wavelength. This short wave IR is helpful in observing ground fog, fires, volcanoes, sea surface temperatures, and clouds. Scientists access other IR images depending upon their interest. A long wave IR, channel 4 (10.2-11.2 mm) is used to show jet stream features, surface temperatures and frost/freeze forecasts. Channel 5 (11.5-12.5 mm) is commonly used to observe daily temperature changes, cold cloud tops, dust, and ash.
The water vapor imagery, channel 3, (6.47-7.02 mm) is an infrared image which allows meteorologists to observe upper-level moisture sources and the presence of humidity within the atmosphere. This will enhance their ability to forecast the development and motion of weather systems.
There are many applications for GOES imagery and sounding data. Many atmospheric researchers and forecasters rely upon this information. Software enhancements enable these users to emphasize their areas of interest.
- The GOES Project Science home page is http://rsd.gsfc.nasa.gov/goesb/chesters/web/goesproject.html
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