GOES stands for Geostationary Operational Environmental Satellite. It is a series of satellites that monitor the United States and adjoining oceans. GOES satellites are positioned above the equator, so they remain in a fixed position in the sky, essentially stationary with respect to a point on Earth. There are two GOES satellites that monitor the continental United States: GOES East and GOES West. GOES East provides a reasonable view of the continental United States, while GOES West has a much better view of Alaska and Hawaii as well as a wide area of the Pacific Ocean.

The GOES satellites have flexible scanning imagers that allow scientists to quickly collect information about cloud cover, wind speed, air temperature, surface moisture and ozone levels. Some GOES satellites also carry instruments such as solar X-ray imagers that provide information about potentially dangerous solar activity and space environment monitoring (SEM) systems to detect the impact of space weather on the Earth’s atmosphere, enabling meteorologists to be more prepared for the effects of sudden, violent solar events.

In addition, GOES satellites are capable of broadcasting Level 1b products to local meteorological field offices through the High Rate Information Transmission service (HRIT) and the Emergency Managers Weather Information Network (EMWIN). These services transmit imagery and selected data to terminals at the local level for display.

Before a satellite is launched, it’s given a letter designation, such as GOES-A. Once a satellite reaches its orbit, it’s then designated with a number, from GOES-1 through GOES-16 (skipping GOES-G, which was a launch failure).

During daylight hours, GOES satellites capture visible light images of the Earth and its clouds. These images help meteorologists identify cloud type and movement, track developing severe weather and provide warnings to the public about impending dangerous conditions.

Visible light images are available only during daylight hours because the Sun emits radiation that is reflected off of cloud tops and the Earth’s surface. The longer wavelengths of thermal infrared radiation that the GOES satellites detect can’t pass through the atmosphere to reach the ground and clouds because oxygen, carbon dioxide, water vapor, methane and ozone absorb them. However, short-wave infrared radiation can reach the ground and clouds, so the GOES satellites can sense these.

The GOES-R satellites have new Advanced Baseline Imagers (ABI) that provide enhanced, more-detailed images of the Earth. GOES-R ABI images will show the entire disk of the Western Hemisphere every 15 minutes, and a scan of a specific storm region can be generated every 30 seconds. Additionally, GOES-16 and -17 will utilize a ten-minute flex mode, which will provide full images of the contiguous United States every 10 minutes, and a scan of two mesoscale domains each minute. The GOES-R system also includes the Data Collection System (DCS) that receives and relays weather observations from 20,000 other platforms around the globe.