Jason A Spot

Jason series

Satellite providing global sea surface height observations for climate monitoring and ocean and seasonal forecasts

Jason A Spot
Jason A Spot

Jason satellites continue a time series of mean sea level rise measurements dating back to 1992.

Last Updated

23 September 2021

Published on

16 April 2020

Jason-3 operates in low Earth orbit at 1336km altitude. Its main instrument is a radar altimeter that provides measurements of sea surface height, wind speed at the ocean surface and significant wave height.

It is the fourth in the series of US/European ocean altimetry satellites (TOPEX-Poseidon, Jason-1, and -2) that, together, have built up a time series of global mean sea level that dates back to 1992.

The Jason satellites fulfil a key role as the reference mission against which ocean altimeters on board other satellites, such as Sentinel-3, are calibrated.

International cooperation

Jason-3 is the result of an international partnership between EUMETSAT, CNES, NOAA, NASA and the European Union, which funds European contributions to Jason-3 operations as part of its Copernicus programme.

EUMETSAT, CNES and NOAA process data from Jason-3, with EUMETSAT being responsible for data services to users of the EUMETSAT and EU Member States, on behalf of the EU Copernicus programme.

This international cooperation has continued with the Jason Continuity of Service programme, which fulfils the Copernicus Sentinel-6 mission.

Through the launch of two next-generation ocean altimetry satellites, in 2020 and 2025, Sentinel-6 will ensure the collection of high-quality sea-level measurement data for the reference mission into the next decade.

Facts and figures

  1. Measurements of ocean topography — the equivalent of surface pressure in the atmosphere — enabling numerical prediction of the three-dimensional ocean, a prerequisite to the development of operational oceanography, in combination with marine meteorology.
  2. Helping improve monthly forecasts, e.g. heatwaves or sustained heavy rainfall, and seasonal forecasts, e.g. a cold winter or a hot summer, due to the sustained influence of the ocean on the atmosphere.
  3. Variations of sea level (some mm per year) in our changing climate can only be monitored on global scale by High Precision Ocean Altimetry (HPOA) observations (composed of Jason-3 and future Jason-CS data), and ocean surface topography measurements are essential to understand how the ocean stores and redistributes heat, water and carbon in the climate system.
  4. Altimeter observations are a unique source of ocean surface wind speed measurements for the validation of the new very high resolution (1 to 2km) regional numerical weather prediction models, to improve short range prediction of high impact weather, such as hurricanes.
    • Jason 2

      • Launch date:
      • 20/06/2008
      • Retirement date:
      • 09/10/2019
      • Details:
      • 1332–1343km, 66° inclination, circular, non-sun-synchronous orbit with 10-day repeat cycle; radar altimeter, microwave radiometer, laser retroreflector, ground- and satellite-based precise orbit determination
    • Jason 3

      • Launch date:
      • 17/01/2016
      • Retirement date:
      • Nominal lifetime five years
      • Details:
      • 1332–1343km, 66° inclination, circular, non-sun-synchronous orbit with 10-day repeat cycle; radar altimeter, microwave radiometer, ground- and satellite-based precise orbit determination
    • Sentinel-6 Michael Freilich (Jason-CS-A)

      • Launch date:
      • 21/11/2020 (planned)
      • Retirement date:
      • Nominal lifetime 5.5 years
      • Details:
      • 1332–1343km, 66° inclination, circular, non-sun-synchronous orbit with 10-day repeat cycle; radar altimeter, microwave radiometer, GNSS radio-occultation, ground- and satellite-based precise orbit determination
    • Sentinel-6B (Jason-CS-B)

      • Launch date:
      • 2025 (planned)
      • Retirement date:
      • Nominal lifetime 5.5 years
      • Details:
      • 1332–1343km, 66° inclination, circular, non-sun-synchronous orbit with 10-day repeat cycle; radar altimeter, microwave radiometer, GNSS radio-occultation, ground- and satellite-based precise orbit determination

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