Artists concept of TOPEX/Poseidon over Earth

Launched in 1992, TOPEX/Poseidon was 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

Fact Sheet

TOPEX/Poseidon Fact Sheet