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Ocean Surface Topography from Space
Artists concept of TOPEX/Poseidon over Earth
Launched in 1992, TOPEX/Poseidon is a joint venture between CNES and NASA that measured ocean surface topography to an accuracy of 4.2 cm, enabled scientists to forecast the 1997-1998 El Niño, and improved understanding of ocean circulation and its effect of global climate. While a 3-year prime mission was planned, with a 5-year store of expendables, TOPEX/Poseidon delivered an astonishing 13+ years of data from orbit. The mission ended in January 2006. In those 13 years, it:

  • Measured sea levels with unprecedented accuracy to better than 5 cm
  • Continuously observed global ocean topography
  • Monitored effects of currents on global climate change and produced the first global views of seasonal changes of currents
  • Monitored large-scale ocean features like Rossby and Kelvin waves and studied such phenomena as El Niño, La Niña, and the Pacific Decadal Oscillation
  • Mapped basin-wide current variations and provided global data to validate models of ocean circulation
  • Mapped year-to-year changes in heat stored in the upper ocean
  • Produced the most accurate global maps of tides ever
  • Improved our knowledge of Earth's gravity field

Mission Highlights

  • The End of An Era - The venerable TOPEX/Poseidon takes its last bow
  • TOPEX/Poseidon Begins its 14th Year! - This tenacious craft has reached the 10th anniversary of the end of its primary mission!
  • TOPEX/Poseidon 12 Years of Service - August 10, 2004: Originally designed for three to five years, the TOPEX/Poseidon spacecraft is still providing valuable ocean altimetry data 12 years later!

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