Meteorologists need sensors that are on the ground directly measuring local weather conditions, as well as in orbit high above Earth’s atmosphere observing the "big picture" remotely. The United States has a network of ground stations for measuring surface and upper-air weather conditions at particular locations and times. However, this network leaves gaps in the information about the geographical extent of weather phenomena, their speed and direction of movement, and their duration. Satellite data are also needed to provide a complete and continuous picture of atmospheric conditions. Forecasting the approach of severe storms since 1975, GOES are a cornerstone of weather observing and forecasting.
Geostationary satellites rotate with Earth from west to east directly over the equator at an altitude of 35,800 km (22,300 statute miles). Because the satellite orbits in the same direction as Earth turns on its axis and matches the speed of Earth’s rotation at the equator, the satellite always has the same view of the Earth’s surface. The U.S. has two Geostationary Operational Environmental Satellites (GOES) in service, one positioned to view the west coast and the Pacific Ocean and one to view the east coast and the Atlantic. Geostationary satellites are in position to maintain a constant vigil over nearly half the planet.
Geostationary weather satellites work by sensing electromagnetic radiation to indicate the presence of clouds, water vapor, and surface features. Unlike ground-based radar systems and some other types of satellites, these satellites do not send energy waves into the atmosphere and analyze returning signals. Rather, the GOES work by passively sensing energy. The GOES sense visible (reflected sunlight) and infrared (for example, heat energy), from the Earth’s surface, clouds, and atmosphere. The Earth and atmosphere emit infrared energy 24 hours a day, and satellites can sense this energy continuously. In contrast, visible imagery is available only during daylight hours when sunlight is reflected.
The instruments on the GOES that measure electromagnetic energy are called radiometers. GOES carries two types of imagers: One measures the amount of visible light from the sun that Earth’s surface or clouds reflect back into space. The second measures the infrared energy that Earth’s surface and clouds radiate back to space. Because the GOES can sense infrared radiation, they can operate at night.
Most visible light passes right through the atmosphere, but no so much through the clouds. Clouds reflect some of the visible light back into space. How much depends upon the thickness and height of the cloud. Earth’s surface absorbs the visible light energy, gets warmer, and re-radiates the energy as infrared radiation. Clouds also absorb some of the visible light energy, as well as the infrared energy re-radiated from Earth. Satellite sensors are particularly sensitive to those wavelengths of infrared energy re-radiated up through to the atmosphere to space. Scientists can measure the height, temperature, moisture content (and more) of nearly every feature of the Earth’s atmosphere, ocean, and land surface, with and without vegetation.
Communications, transportation, and electrical power systems can be disrupted and damaged by space weather storms. Exposure to radiation can threaten astronauts and commercial air travelers alike, and has affected the evolution of life on Earth. Geomagnetic storms and other space weather phenomena pose a serious threat to all space operations, and can result in total mission failure.
Beginning with GOES-I, the Search and Rescue subsystem has been carried on each of the GOES. Distress signals are broadcast by Emergency Locator Transmitters carried on general aviation aircraft, aboard some marine vessels, and by individuals, such as hikers and climbers. A dedicated transponder on each GOES detects and relays signals to a Search and Rescue Satellite-Aided Tracking (SARSAT) ground station. Through a rescue coordination center, help is dispatched to the aircraft, ship, or individual in distress. SARSAT is an international program, with many satellites making up a world-wide network of emergency beacon transponders. Since 1982, SARSAT helped save more than 39,000 lives worlwide. Learn more.
GOES-R is the next generation of NOAA geostationary Earth-observing systems. The satellite’s advanced spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. » More
GOES-R advanced spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. The Advanced Baseline Imager (ABI) will collect three times more data and provide four times better resolution and more than five times faster coverage than current GOES. The GOES-R series satellites will also carry the first lightning mapper flown from geostationary orbit. The Geostationary Lightning Mapper, or GLM, will map total lightning (in-cloud and cloud-to-ground) continuously over the Americas and adjacent ocean regions. Research has shown that lightning flash rate increases can be a predictor of impending severe weather and total lightning data from GLM has great potential to increase lead time for severe thunderstorm storm warnings. The satellites will also host a suite of instruments that will provide significantly improved detection of space weather for more accurate monitoring of energetic particles responsible for radiation hazards, improved power blackout forecasts, increased warning of communications and navigation disruptions, and more.
It is the consolidated backup facility from which NOAA will command and control the GOES-R satellites in the event the primary satellite operating locations (NOAA Satellite Operations Facility and Wallops Command and Data Acquisition Station) become disabled. It includes the components, antennas and ground infrastructure needed to communicate with the GOES-R series satellites to control the spacecraft and capture the telemetry and science data from the instruments. This site will be able to perform all of the operational functions in case of a failover scenario at the NSOF and/or WCDAS ground segment facilities. The CBU is located at the I-79 Technology Park Research Center in Fairmont, West Virginia. » Learn More
The GOES-R Series Program is engaging users early in the process through Proving Ground and NOAA testbed activities, simulated data sets, scientific and user conferences, and other communication and outreach efforts. » Learn more about user readiness efforts here.
he Proving Ground is a collaborative effort between the GOES-R Program Office, NOAA Cooperative Institutes, a NASA center, NWS Weather Forecast Offices, NCEP National Centers, and NOAA testbeds across the country. The Proving Ground is a project in which simulated GOES-R products can be tested and evaluated before the GOES-R satellite is launched. The simulated GOES-R products are generated using combinations of currently available GOES data, data provided by instruments on polar-orbiting satellites, and model synthetic satellite data.
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GOES Rebroadcast is the primary space relay of Level 1b products from GOES-R and will replace the GOES VARiable (GVAR) service. GRB will provide full resolution, calibrated, navigated, near-real-time direct broadcast data. » Learn more about GRB.
Users must either acquire new systems to receive GRB or upgrade components of their existing GVAR systems. At a minimum, GVAR systems will require new receive antenna hardware, signal demodulation hardware, and computer hardware/software system resources to ingest the extended magnitude of GOES-R GRB data. See the GRB Downlink Specifications and GRB Product Users Guide (PUG) documents for more information.
The GRB Simulators allow for on-site testing of user ingest and data handling systems, aka GRB field terminal sites. Each unit simulates GRB downlink functionality by generating Consultative Committee for Space Data Systems (CCSDS) formatted GRB output data based on user-defined scenarios, test patterns, and proxy data files. Four GRB simulators have been designated for loan to borrowers who manufacture GRB receivers and other users interested in testing their receive systems. The objective is to allow borrower access to simulators to verify GRB receive system compatibility with the GRB transmission. Information about requesting a simulator for loan can be found at http://go.usa.gov/WvXY. For a complete list of frequently asked questions about the GRB Simulator, see the GRB Simulator FAQs document.
When GOES-R is launched in November 2016 it will be placed in the 89.5° checkout orbit. It has not yet been determined where GOES-R will be placed in operational orbit. The final decision will be based on the health/safety/performance of the GOES constellation. NOAA's Office of Satellite and Product Operations will be responsible for determining the operational orbit for GOES-R.