The Sentinel-6 radar altimeter mission is part of the Copernicus Programme, with the objective of providing high-precision measurements of global sea-level.

Jason-CS overview (tn)

The Jason-CS Programme is EUMETSAT's direct contribution to the funding, development and implementation of the Sentinel-6 mission, also involving ESA, the EU and NOAA.

Sentinel-6 aims to continue high precision ocean altimetry measurements in the 2020–2030 time-frame using two successive, identical satellites, Jason-CS-A and Jason-CS-B.

A secondary objective of Sentinel-6 is to collect high resolution vertical profiles of temperature, using the GNSS Radio-Occultation sounding technique, to assess temperature changes in the troposphere and stratosphere and to support Numerical Weather Prediction.


  • EUMETSAT is leading the system definition and is responsible for the ground segment development; operations preparation and operations of both satellites, and will co-fund the second satellite, together with the European Commission (EC).
  • ESA is responsible for the development of the first satellite; the prototype processors; delivery of the LEOP services, and the procurement of the second satellite on behalf of EUMETSAT and the EC.
  • The EC co-funds the second satellite with EUMETSAT and funds the operations of Jason-3 and both Sentinel-6 satellites, including the LEOP service for the second satellite.
  • NOAA provides the launch services for both Sentinel-6 satellite; US payload instruments and ground segment support, and will contribute to the operations.


  • Measurements of ocean topography, being the equivalent of surface pressure in the atmosphere, are enabling numerical prediction of the three-dimensional ocean, which is a prerequisite to the development of operational oceanography in synergy with marine meteorology.
  • The development of operational oceanography is, in turn, necessary to improve forecasts of the weather conditions likely to prevail two to four weeks ahead (monthly forecasts), e.g. heat waves or sustained heavy downpours, and in the next seasons (seasonal forecasts) e.g. a cold winter or a hot summer, as a result of the sustained influence of the ocean on the atmosphere.
  • Variations of sea level (some mm per year) in our changing climate can only be monitored on global scale by HPOA observations, and ocean surface topography measurements are essential to understand how the ocean stores and redistributes heat, water and carbon in the climate system.

Characteristics and Instruments

The proposed payload is composed of the following instruments:

  • a radar altimeter, developed by ESA, based on the Sentinel-3 SARL instrument, but with a design adopted to allow the interleaved mode combining the SAR and the LRM modes;
  • AMR-C Microwave radiometer, provided by NOAA;
  • GNSS Precise Orbit Determination (POD) Receiver, developed by ESA and derived from the GNSS Receiver on Sentinel-3;
  • the same DORIS Receiver as on Jason-3 and Sentinel-3;
  • the same Laser Reflector Array as on Jason-3, provided by NOAA;
  • radio-occultation instrument based on a Tri-G receiver, provided by NOAA.

Services and Applications

The main aim is the continuity of service with the Jason-2/3 missions, including meeting user requirements to provide a reference for cross-calibrating other altimetry missions, in particular from the Copernicus Sentinel-3 marine mission, also operated by EUMETSAT.

Main Jason-CS products, key variables and applications
  Products Main variables Main applications
Near Real Time (NRT) Operational Geophysical Data Record (OGDR) Significant Wave Height (SWH)
Surface Wind Speed (WIND)
Sea Surface Height (SSH)
Real time operational oceanography
Marine nowcasting
Operational wave forecasting
Slow Time Critical (STC) Interim Geophysical Data Record (IGDR) Same as above plus Absolute Dynamic Topography (ADT)
Ocean Geostrophic Velocities
More accurate Sea Surface Height (SSH)
Operational oceanography
Seasonal Forecasting
Non Time Critical (NTC) Geophysical Data Record (GDR) Same as above
Most accurate Sea Surface Height (SSH)
Sea level monitoring
Climate monitoring
Climate research