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Ocean Surface Topography from Space
Jason-1 Celebrates Five Years in Orbit - Ocean Data Continues to Flow
December 01, 2006

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Jason-1 launch, December 7, 2001
Jason-1 launch, December 7, 2001.
Image credit: NASA/JPL
Jason-1 completes its 5th year on orbit on 7 December 2006. From its vantage point 1,330 kilometers (860 miles) above Earth, this follow-on to the highly successful TOPEX/Poseidon mission has provided measurements of the surface height of the world's oceans to an accuracy of 3.3 centimeters (1.3 inches). With this milestone, Jason-1 surpasses both its primary and extended mission phases and continues to collect valuable ocean data for researchers and operational users worldwide.

A joint program of NASA and the Centre National d'Etudes Spatiales (CNES) in France, Jason-1 has vastly improved our understanding ocean circulation and its effect on global climate.

The primary objectives of Jason-1 include;

  • Extending the ocean-surface topography time measurements begun by Topex/Poseidon into the 21st century
  • Increasing our understanding of ocean circulation
  • Improving climate forecasting
  • Measuring global sea-level change
  • Improving coastal tide models

Some of the important ongoing science investigations for Jason-1 include;

  • Studying ocean variability on decadal scales and its relations to climate
  • Understanding how changes in the ocean's heat content and mass affect global sea level
  • Producing better tide models for the coastal oceans where the scales of tides are too small to be resolved by a single altimeter.
  • Studying ocean eddies and their effects on large-scale ocean circulation and heat transport.
  • Assimilating altimetry data with wind, temperature, and salinity data for improved prediction of El Niño-related climate events.

TOPEX/Poseidon enabled scientists to forecast the impact of the 1997-1998 El Niño. Jason-1 has viewed several
less dramatic climate events in the Pacific Ocean, including the current mild El Niño and slow changes in the
Pacific Decadal Oscillation.

The next-generation NASA ocean altimetry mission, which will be the follow-on to Jason-1, is the
Ocean Surface Topography Mission (OSTM) on Jason-2. This joint mission, with partners CNES, Eumetsat,
and NOAA, will extend the ocean-surface topography time series even further, and is scheduled to launch in 2008.

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