How to Interpret Satellite Imagery

Classic Satellite Maps

Satellite Imagery on WunderMap

Satellites provide data from space to monitor the Earth to analyze the coastal waters, relay life-saving emergency beacons, and track tropical storms and hurricanes. The National Oceanic and Atmospheric Administration (NOAA) operates two types of satellite systems for the United States - geostationary satellites and polar-orbiting satellites. Geostationary satellites constantly monitor the Western Hemisphere from around 22,240 miles above the Earth, and polar-orbiting satellites circle the Earth and provide global information from 540 miles above the Earth.

Satellites enable us to provide consistent, long-term observations, 24 hours a day, 7 days a week. They track fast breaking storms across "Tornado Alley" as well as tropical storms in the Atlantic and Pacific oceans. In addition to weather, data from satellites are used to measure the temperature of the ocean, which is a key indicator of climate change. Satellite information is also used to monitor coral reefs, harmful algal blooms, fires, and volcanic ash. Monitoring the Earth from space helps us understand how the Earth works and affects much of our daily lives.

Infrared (IR) Satellite Imagery

"Infrared" satellite imagery, sometimes referred to as "IR" or "IR4", allows you to see cloud cover whether it is day or night. Infrared satellite instruments measure the temperature of cloud tops, which we can translate into cloud cover. Since air temperature generally decreases with increasing altitude, cooler clouds are located higher in the atmosphere. In the image above, yellows, oranges, reds, and pinks correspond to high clouds, while blues and greys correspond to low clouds.

Visible Satellite Imagery

"Visible" satellite imagery is a snapshot of the earth and is only available during the day as it uses light from the sun to detect the clouds. Low clouds are dark and high clouds are lighter.

Geostationary Satellites (GOES)

GOES satellites provide continuous monitoring of weather patterns. 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 spot on the Earth's 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.

Polar-Orbiting Satellites (POES)

Polar-orbiting satellites offer the advantage of daily global coverage. Because of the polar orbiting nature of the POES series satellites, these satellites are able to collect global data on a daily basis for a variety of land, ocean, and atmospheric applications. Data from polar-orbiting satellites aids in weather analysis and forecasting, climate research and prediction, global sea surface temperature measurements, atmospheric soundings of temperature and humidity, ocean dynamics research, volcanic eruption monitoring, forest fire detection, global vegetation analysis, search and rescue, and many other applications.

Sources: NOAA, NWS