Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc. Geostationary satellites hover over the same spot, providing continuous monitoring to a portion of the Earth's surface. Polar orbiting satellites provide global coverage, but only twice per day at any given spot.
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Weather
A weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while moving at the angular velocity of the Earth's rotation.[1] These meteorological satellites, however, see more than clouds and cloud systems. City lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc., are other types of environmental information collected using weather satellites.
Weather satellite images helped in monitoring the volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna.[2] Smoke from fires in the western United States such as Colorado and Utah have also been monitored.
El Niño and its effects on weather are monitored daily from satellite images. The Antarctic ozone hole is mapped from weather satellite data. Collectively, weather satellites flown by the U.S., Europe, India, China, Russia, and Japan provide nearly continuous observations for a global weather watch.
Environmental monitoring
Other environmental satellites can assist environmental monitoring by detecting changes in the Earth's vegetation, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average.[3] For example, the 2002 oil spill off the northwest coast of Spain was watched carefully by the European ENVISAT, which, though not a weather satellite, flies an instrument (ASAR) which can see changes in the sea surface.
Mapping
Terrain can be mapped from space with the use of satellites, such as RADARSAT-1.[4]
See also
- Earth Observing System - a NASA program comprising a series of satellite missions
- List of Earth observation satellites
References
- ^ NESDIS. Satellites. Retrieved on 2008-07-04.
- ^ NOAA. NOAA Satellites, Scientists Monitor Mt. St. Helens for Possible Eruption. Retrieved on 2008-07-04.
- ^ NASA. Drought. Retrieved on 2008-07-04.
- ^ Grunsky, E.C. The use of multi-beam RADARSAT-1 satellite imagery for terrain mapping. Retrieved on 2008-07-04.
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