NOAA Satellite Information System

NOAA's Geostationary and Polar-Orbiting Weather Satellites

Operating the country's system of environmental satellites is one of the major responsibilities of the National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS). NESDIS operates the satellites and manages the processing and distribution of the millions of bits of data and images theses satellites produce daily. The primary customer is NOAA's National Weather Service, which uses satellite data to create forecasts for the public, television, radio, and weather advisory services. Satellite information is also shared with various Federal agencies, such as the Departments of Agriculture, Interior, Defense, and Transportation; with other countries, such as Japan, India, and Russia, and members of the European Space Agency (ESA) and the United Kingdom Meteorological Office; and with the private sector.

NOAA's operational weather satellite system is composed of two types of satellites: geostationary operational environmental satellites (GOES) for short-range warning and "now-casting" and polar-orbiting satellites for longer-term forecasting. Both types of satellite are necessary for providing a complete global weather monitoring system.

A new series of GOES and polar-orbiting satellites has been developed for NOAA by the National Aeronautics and Space Administration (NASA). The new GOES-R series provide higher spatial and temporal resolution images and full-time operational soundings (vertical temperature and moisture profiles of the atmosphere). The newest polar-orbiting meteorological satellites (National Polar-orbiting Operational Environmental Satellite System in 2014) will provide improved atmospheric temperature and moisture data in all weather situations. This new technology will help provide the National Weather Service the most advanced weather forecast system in the world.

Geostationary Operational Environmental Satellites (GOES)

Small image of GOES Satellite

GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. They circle the Earth in a geosynchronous orbit, which means they orbit the equatorial plane of the Earth at a speed matching the Earth's rotation. This allows them to hover continuously over one position on the surface. The geosynchronous plane is about 35,800 km (22,300 miles) above the Earth, high enough to allow the satellites a full-disc view of the Earth. Because they stay above a fixed spot on the surface, they provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms, and hurricanes. When these conditions develop the GOES satellites are able to monitor storm development and track their movements.

GOES satellite imagery is also used to estimate rainfall during the thunderstorms and hurricanes for flash flood warnings, as well as estimates snowfall accumulations and overall extent of snow cover. Such data help meteorologists issue winter storm warnings and spring snow melt advisories. Satellite sensors also detect ice fields and map the movements of sea and lake ice.

NASA launched the first GOES for NOAA in 1975 and followed it with another in 1977. Currently, the United States is operating GOES-15 and GOES-13. (GOES-12, which is partially operational, supports Central and South America to prevent data outages during the GOES-13 rapid scan operations.) GOES-14 is being stored in orbit as a replacement for either GOES-15 or GOES-13, in the event of failure.


GOES-15 and GOES-13

The United States normally operates two meteorological satellites in geostationary orbit over the equator. Each satellite views almost a third of the Earth's surface: one monitors North and South America and most of the Atlantic Ocean, the other North America and the Pacific Ocean basin. GOES-13 (or GOES-East) is positioned at 75 W longitude and the equator, while GOES-15 (or GOES-West) is positioned at 135 W longitude and the equator. The two operate together to produce a full-face picture of the Earth, day and night. Coverage extends approximately from 20 W longitude to 165 E longitude. This figure shows the coverage provided by each satellite.

Representation of GOES View from space

The main mission is carried out by the primary instruments, the Imager and the Sounder. The imager is a multichannel instrument that senses radiant energy and reflected solar energy from the Earth's surface and atmosphere. The Sounder provides data to determine the vertical temperature and moisture profile of the atmosphere, surface and cloud top temperatures, and ozone distribution.

Other instruments on board the spacecraft are a Search and Rescue transponder, a data collection and relay system for ground-based data platforms, and a space environment monitor. The latter consists of a magnetometer, an X-ray sensor, a high energy proton and alpha detector, and an energetic particles sensor. All are used for monitoring the near-Earth space environment or solar "weather." GOES-15, the newest satellite also carries a Solar X-Ray Imager (SXI).


GOES-15 Characteristics
Main Body: 2.56 m (8.08 ft) by 4.6 m (15.0 ft) by 2.9 m (9.4 ft)
Solar Array: Length - solar array: 8.2m (26 ft 9 in)

Width - Antenna: 2.25 m x 3.37 m (7 ft 4 in x 11 ft)
Weight at Liftoff: 7,136 lbm (3,238 kg)
Launch Vehicle: Delta IV
Launch Date: March 04, 2010 Cape Canaveral Air Station, FL.


Orbital information:
Type: Geosynchronous
Altitude: 35, 780 km (22, 233 statute miles)
Period: 1,436 minutes
Inclination: 0.180087 degrees


Space Environment Monitor (SEM)
Solar X-Ray Imager (SXI)
Data Collection System (DCS)
Search and Rescue (SAR) Transponder

For users who establish their own direct readout receiving station, the GOES satellites transmit low resolution imagery in the LRIT service. LRIT can be received with an inexpensive receiver. Highest resolution Imager and Sounder data is found in the GVAR primary data user service which requires more complex receiving equipment. More information about establishing receiving stations can be obtained from the Email contact at the bottom of the page.

For more detailed information about the GOES satellites, see the GOES N DataBook Revision 5.2.2, published 16 March 2006 by Boeing Satellite Development Center. The most recent pictures received directly from the NOAA GOES satellites can be found at the NOAA GOES Server.


Polar-Orbiting Satellites

Small image of POES Satellite


Complementing the geostationary satellites are two polar-orbiting satellites known as Advanced Television Infrared Observation Satellite (TIROS-N or ATN), constantly circling the Earth in an almost north-south orbit, passing close to both poles. The orbits are circular, with an altitude between 830 (morning orbit) and 870 (afternoon orbit) km, and are sun synchronous. One satellite crosses the equator at 7:30 a.m. local time, the other at 1:40 p.m. local time. The circular orbit permits uniform data acquisition by the satellite and efficient control of the satellite by the NOAA Command and Data Acquisition (CDA) stations located near Fairbanks, Alaska and Wallops Island, Virginia. Operating as pair, these satellites ensure that data for any region of the Earth are no more than six hours old.

A suite of instruments is able to measure many parameters of the Earth's atmosphere, its surface, cloud cover, incoming solar protons, positive ions, electron-flux density, and the energy spectrum at the satellite altitude. As a part of the mission, the satellites can receive, process and retransmit data from Search and Rescue beacon transmitters, and automatic data collection platforms on land, ocean buoys, or aboard free-floating balloons. The primary instrument aboard the satellite is the Advanced Very High Resolution Radiometer or AVHRR.


NOAA-19 Characteristics
Main body: 4.2m (13.75 ft) long, 1.88m (6.2 ft) diameter
Solar array: 2.73m (8.96 ft) by 6.14m (20.16 ft)
Weight at Liftoff: 1419.8 kg (3130 pounds) including 4.1 kg of gaseous nitrogen
Launch Vehicle: Delta-II 7320-10 Space Launch Vehicle
Launch Date: February 06, 2009 Vandenburg Air Force Base, CA
Orbital information: Type: sun synchronous
Altitude: 870 km
Period: 102.14 minutes
Inclination: 98.730 degrees
Sensors: Advanced Very High Resolution Radiometer (AVHRR/3)
Advanced Microwave Sounding Unit-A (AMSU-A)
Microwave Humidity Sounder (MHS)
High Resolution Infrared Radiation Sounder (HIRS/4)
Solar Backscatter Ultraviolet Spectral radiometer (SBUV/2)
Space Environment Monitor (SEM/2)
Search and Rescue (SAR) Repeater and Processor
Advance Data Collection System (ADCS)


The polar orbiters are able to monitor the entire Earth, tracking atmospheric variables and providing atmospheric data and cloud images. They track weather conditions that eventually affect the weather and climate of the United States. The satellites provide visible and infrared radiometer data that are used for imaging purposes, radiation measurements, and temperature profiles. The polar orbiters' ultraviolet sensors also provide ozone levels in the atmosphere and are able to detect the "ozone hole" over Antarctica during mid-September to mid-November. These satellites send more than 16,000 global measurements daily via NOAA's CDA station to NOAA computers, adding valuable information for forecasting models, especially for remote ocean areas, where conventional data are lacking.

Find out about the first United States weather satellite launched in 1960. For more technical information on the NOAA polar-orbiting satellites, see the NOAA-KLM User's Guide, and the NOAA - L Advanced TIROS-N (ATN) Pamphlet. Link to the USGS site for more information about the AVHRR instrument.

Currently, NOAA is operating five polar orbiters. A new series of polar orbiters, with improved sensors, will began with the launch of NPP in October, 2011. The newest, NOAA-19, was launched February 07, 2009. NOAA-18, NOAA-17, NOAA-16 and NOAA-15 all continue transmitting data as stand-by satellites. NOAA-19 is classified as the "operational" satellite.


How Satellites Are Named

NOAA assigns a letter to the satellite before it is launched, and a number once it has achieved orbit. For example, GOES-O, once in orbit, was designated GOES-14, GOES-G, which was lost at launch, was never assigned a number. The same system is used for polar orbiters; for example, NOAA¬-18, still in orbit, was designated NOAA-N before launch. NOAA-N Prime became NOAA-19.


Additional Links to Information

Other sites to visit: NASAs GOES Project Office and POES Project Office. Find out about the U.S. military meteorological satellite program, DMSP. Examples of NOAA polar orbiting satellite imagery of significant weather events can be found at the JHU Applied Physics Laboratory web site. A collection of pictures (NOAA in Space) related to NOAA satellites can be found at the NOAA Library. There is a brief history of the GOES satellites from NASA. Florida State University has a history of many of the NOAA satellites and details of when they were launched.


Other United States and Non-U.S. Satellites

Many other environmental satellites are operated by nations, international organizations and commercial enterprises. Below are links to more information to a sampling of these other satellite systems.


[NOTICE: When following some of the links listed above, you will leave the NOAASIS web site and the NOAA domain. We provide these links since the information may be of interest to our users. However, NOAA does not necessarily endorse the content of any of these sites.]

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