GOES stands for Geostationary Operational Environmental Satellite. GOES is NOAA’s constellation of operational weather satellites. They are all in geostationary orbit 35,790 kilometres (22,240 miles) above Earth. They monitor the United States and adjoining oceans.
Each GOES satellite has two instruments, the Imager and Sounder. The Imager senses reflected and emitted solar energy, detects infrared radiation, and provides observations of the temperature and water vapour distribution in the atmosphere. The Sounder measures the vertical structure of the atmosphere and identifies surface and cloud top temperatures, ozone, and moisture. The Sounder’s instrument design allows it to “stare” at a given area of the Earth for extended periods, providing detailed observations of atmospheric phenomena.
The satellites can also relay environmental data transmissions sent from remote Automatic Data Collection Platforms (ACPs). In addition, the GOES Satellite Emergency Communications System provides distress signal detection and communication with rescue stations for search and rescue operations.
The GOES satellites are owned by NOAA, but their development and launch was managed by the National Aeronautics and Space Administration (NASA). In addition to its primary mission, GOES has provided platforms for the Solar X-ray Imager and the Space Environment Monitoring (SEM) instrument package, both operated by NOAA/SEC in Boulder, Colorado.
As GOES passes overhead, it takes images of the Earth every three minutes. These images are a key part of meteorologists’ analysis of severe weather events, such as severe thunderstorms and hurricanes.
When a storm approaches, meteorologists look at the pattern of clouds in a series of GOES images to determine its speed and direction. This information, combined with other weather data, is used to forecast the storm’s impacts.
Observation data from the Imager and Sounder are transmitted continuously to the NOAA Satellite Operations Control Center in Suitland, Maryland. From there, they are broadcast on an as-needed basis by a variety of satellite communication systems.
The Imager and Sounder on GOES-R have enhanced resolution, new calibration and stability improvements, and additional science channels that will allow for improved detection of atmospheric phenomena. The GOES-R series will also include a new Coronagraph instrument to monitor the presence of dangerous coronal mass ejections that could impact space assets and astronauts.
The GOES-R Imager, Sounder, and Geostationary Environmental Data Acquisition Suite (GEDAS) instrument packages use a servo-driven, two-axis, gimballed mirror system in conjunction with a 31 cm Cassegrain telescope to form the sensor’s primary optical instruments. This enables the instrument to “stare” at a particular area of the Earth, allowing close-up continuous observations of severe storms. In addition, the GOES-R Imager and Sounder employ flexible scan control to observe a range of spatial scales, from global scenes (Earth’s full disk) to localized imagery for rapid response to critical events. Geographic information is stored with each GOES-R Level 1b and Level 2 product as tower geodetic latitude and longitude coordinates, which are converted to ABI scan angle coordinates using equations based on the Geodetic Reference System 1980 ellipsoid. This transformation is needed to accurately map eddy covariance tower locations on the ABI’s fixed grid.