When You Watch the News and See Pictures of Weather from Around the United States Or The

Satellites

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When you watch the news and see pictures of weather from around the United States or the world, you are seeing data from NOAA’s environmental satellites. NOAA’s environmental satellites provide data from space to monitor the Earth to analyze thecoastal waters, relaylife-saving emergency beacons, andtrack tropical storms and hurricanes.

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. Theytrack fast breaking stormsacross “Tornado Alley” as well as tropical storms in the Atlantic and Pacific oceans. Data from satellites are used to measure thetemperature of the ocean, which is a key indicator of climate change. Satellite information is used to monitorcoral reefs,harmful algal blooms,fires, andvolcanic ash. Monitoring the Earth from space helps us understand how the Earth works and affects much of our daily lives. Alisting of all satellite productsis available on the website of NOAA'sSatellite and Information Service.

NOAA's satellites provide other services beyond justimaging the Earth. Monitoring conditions inspace and solar flaresfrom the sun help us understand how conditions in space affect the Earth. Satellites also relay position information fromemergency beaconsto help save lives when people are in distress on boats, airplanes, or in remote areas. Scientists also use adata collection systemon the satellites to relay data from transmitters on the ground to researchers in the field.

Historical data from our satellites, and other air-based and ground-based observation platforms, is archived for public use at NOAA’sworld-class national data centers.

In addition to operating our own satellites, NOAA helps promote and enable commercial uses of satellites and space to benefit the U.S. economy. NOAA providesa voice for the U.S. commercial space industrywithin government decision making processes. NOAA issueslicensesfor the operation of commercial imaging satellites. NOAA also plays a key part in thenational management of the Global Positioning System, a satellite technology that has become vital to the U.S. economic infrastructure.

Types of satellite images:

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VISIBLE IMAGERY:Visible satellite pictures can only be viewed during the day, since clouds reflect the light from the sun. On these images, clouds show up as white, the ground is normally grey, and water is dark. In winter, snow-covered ground will be white, which can make distinguishing clouds more difficult. To help differentiate between clouds and snow, looping pictures can be helpful; clouds will move while the snow won't. Snow-covered ground can also be identified by looking for terrain features, such as rivers or lakes. Rivers will remain dark in the imagery as long as they are not frozen. If the rivers are not visible, they are probably covered with clouds. Visible imagery is also very useful for seeing thunderstorm clouds building. Satellite will see the developing thunderstorms in their earliest stages, before they are detected on radar.

INFRARED IMAGERY:Infrared satellite pictures show clouds in both day and night. Instead of using sunlight to reflect off of clouds, the clouds are identified by satellite sensors that measure heat radiating off of them. The sensors also measure heat radiating off the surface of the earth. Clouds will be colder than land and water, so they are easily identified. Infrared imagery is useful for determining thunderstorm intensity. Strong to severe thunderstorms will normally have very cold tops. Infrared imagery can also be used for identifying fog and low clouds. The fog product combines two different infrared channels to see fog and low clouds at night, which show up as dark areas on the imagery.

WATER VAPOR IMAGERY:Water vapor satellite pictures indicate how much moisture is present in the upper atmosphere (approximately from 15,000 ft to 30,000 ft). The highest humidities will be the whitest areas while dry regions will be dark. Water vapor imagery is useful for indicating where heavy rain is possible. Thunderstorms can also erupt under the high moisture plumes.