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BBC NEWS | Science/Nature | Measuring sea level rise from space
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1. Jason-2 satellite: From its 1,338km-high circular orbit, the craft maps 95% of the world's ice-free oceans' topography every 10 days
2, GPS satellites: The system is used to track Jason-2's position, ensuring very precise sea level height measurements
3. Sea height measurement via Poseidon-3 altimeter: The dual frequency radar signals are able to measure sea level height, wave height and surface wind speed
4. Sea surface topography: Variations in the height of the sea surface, when combined with measurements from other satellites and in-situ instruments, will allow scientists to improve weather and climate system models
5. Doppler Orbitography and Radiopositioning Integrated by Satellite (Doris) and laser ranging beacon: Ground stations ensure the precise positioning of Jason-2, which enables researchers to gather meaningful data from the satellite[/TD]
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