Since then, it has been replaced by Sentinel-6 Michael Freilich, and very recently Sentinel-6B (still in calibration phase), thus continuing the uninterrupted series of measurements which began with Topex/Poseidon.
The satellite is still functioning very well, but since the summer of 2025 it has been in a slightly different orbit (shifted by 2 km), enabling "geodetic" measurements. 

We are pleased to announce that nominal production of Jason-3 IGDR products resumed yesterday, February 19, 2025, with the GDR-G standard. The records in this release start with Cycle 500 of Pass 206 (January 30, 2025) - forward.

If you already have an AVISO account, data access is available through the following services:

CNES AVISO FTP/SFTP (with AVISO+ credentials)

o FTP access: ftp-access.aviso.altimetry.fr:21

o SFTP access: ftp-access.aviso.altimetry.fr:2122

CNES THREDDS Data Server, TDS (with AVISO+ credentials)

o TDS access: https://tds-odatis.aviso.altimetry.fr/thredds/catalog/catalog.html

○ https://tds-odatis.aviso.altimetry.fr/thredds/catalog/dataset-l2-geophysical-data-record-jason-3-igdr/catalog.html

The series of altimetry satellites initiated by Nasa and Cnes in 1992 is still going on. They have been measuring sea level with a very high accuracy for more than 30 years now. The series is now maintained by Europe, through the Sentinel program, and by the United States. On the other hand, a new part of the cooperation between Cnes and Nasa has recently been deployed with the launch of Swot one month ago.

First, the Poseidon core instrument will be commanded to WAIT mode at 13:36z, stopping the scientific telemetry availability until the repositioning maneuvers are complete.

Two 5km SMA increasing maneuvers will then be executed at 19:42z and 22:30z. They will be followed by two additional positive thrusts on April 11th, and a drift period until April 17th, when lowering maneuvers will start.

The objective of these maneuvers is to reach on April 25th an orbit enabling an interlaced grid with the S6-MF reference, and a separation of approximately 5 days with S6-MF for the measurements, thus doubling the measurement capacity on the reference orbit.

Once those maneuvers are achieved, Poseidon will be restarted, and the mission will be fully operational, with a cycle number reset to 300.

Due to the uncertainties on the maneuvers, the exact date and time of the restart is still unknown, and should happen at the beginning of the week of April 25th. We will of course keep you updated on the exact time and date of the restart as soon as they are known.

Jason-3 remains available for a future tandem phase with Sentinel-6 MF, in order to monitor the potential drifts, and wishes to S6-MF a long and successful life as the Reference Altimetric Mission.

Christophe Marechal / CNES JASON-3 project manager, on behalf 4P project managers, at EUMETSAT, NOAA, and JPL.

The ocean altimetry technique used by Jason-3 is still the most efficient to measure ocean circulation and its variations, as well as the rise of the mean sea level. However, next April, Jason-3 will hand over to Sentinel-6MF, a Copernicus mission designed on the specifications of the Jason system in order to extend the long series of continuous measurements that began in 1993 with TOPEX/POSEIDON. Jason-3, following Jason-2, remained the world reference mission for ocean altimetry measurements for five years: after a validation phase of the quality of Sentinel-6 products in which CNES actively participated, it was deemed sufficient for Sentinel-6 to take over. Next April, Jason-3 will be re-orbited for a new purpose.

Like its predecessors, Jason-3 has enabled many researchers around the world to study and understand ocean phenomena, which play a fundamental role in the evolution of our planet's climate. For example, it has helped to prove and quantify a rise in the average level of the oceans of 3.51 millimeters per year: a measurement that today is no longer in doubt, and which is crucial for the assessment and management of climate change, whose impact is proving to be catastrophic in certain coastal areas or island systems.

In addition, its ability to deliver data in a very short time (typically less than three hours) allows CNES' European (EUMETSAT) and American (NOAA) meteorological partners to interpret its measurements and incorporate them into their climate forecasting models, especially for hurricanes.

Next April, Jason-3 will remain at its initial altitude but will take an opposite orbital position to Sentinel-6, so as to interweave its measurement grid with the reference, and thus double the global measurement capacity. In a few years, when deemed necessary, Jason-3 will return in formation with Sentinel-6, in order to calibrate very precisely the drifts of the instruments. Given the long duration (more than 30 years) of the sea level series, this verification is indeed crucial.

Thanks to the extreme accuracy of its altimetry, radiometry and orbitography instruments (for example DORIS, a CNES instrument whose accuracy of location of a few millimeters is essential to the system's performance), the JASON family (of which Sentinal-6 is a part) fully justifies the renewal of ocean altimetry solutions, and proudly paves the way for future, highly innovative missions in this field, such as SWOT in 2023.

• Updated orbit model POE-F
• Updated geophysical corrections:
  • FES2014 & GOT4.10 ocean tide models
  • CNES/CLS 2015 and DTU 2018 Mean Sea Surface
  • CNES/CLS 2018 Mean Dynamic Topography model
  • New Wet & dry tropospheric model correction based on 3D ECMWF fields
  • New Atmospheric Attenuation model correction based on 3D ECMWF fields
  • S. Desai pole tide with 2017 IERS linear mean pole
  • 3-Parameter SSB (SWH, wind and swell)
  • Smoothed ionospheric bifrequency correction
• Data referenced wrt WGS84
• New geophysical corrections:
  • E. Zaron internal tide model
  • Sandwell & Smith Global Slope Correction
• A new ssha formula : substraction of Internal Tides & Non-equilibrium Ocean Tides
• A new AMR calibration that references the absolute calibration that we expect to receive from Sentinel-6
• A new retracking at GDR level : Adaptive retracking
• A new waveform classification based on neural network
• New additional fields :
  • Coastal distance
  • OISST 
  • OSISAF ice concentration
  • MFWAM swell period & direction
  • Jason-CS/Sentinel6 rain flag approach
• A new way to take into account the instrumental filter calibration (CAL2)
• A large renaming of NetCDF variables, use of NetCDF groups (reconciliation with S6/JCS format)
• NetCDF-4/HDF5 classic model format with native compression

The user documentation (User Product Description and Handbook) are available on AVISO+ website :

• hdbk_j3_GDR_F.pdf
• product_description_j3.pdf 

Samples of GDR-F files are available on AVISO+ ftp
This modification concerns the Native products as well as the Sensor products (SGDRs) and the Reduced products (GDR-SSHA)
Note that the GDR-F standard has no backward compatibility with GDR-D, due to variables renaming and the use of NetCDF groups.
After the standard switch, a double standard production âGDR-Dâ and âGDR-Fâ will be mainted during three months at IGDR and GDR levels.
The whole lifetime of Jason-3 data will be reprocessed with GDR-F standard, delivery is scheduled April 2021.
The Jason-2 reprocessing at GDR-F standard is scheduled end 2021.
Please, feel free to contact us for any question (aviso@altimetry.fr).
François Bignalet-Cazalet, on behalf of the Jason-3 GDR-F Team

Further information:

• Ocean indicators: Mean Sea Level, Processing and Corrections
• Altimetry in videos for Jason-3 launch: Mean Sea Level
• Applications: Mean Sea Level, Greenhouse effects

Further information:

• Missions: Jason-3
• Data: 
  • Level-2: GDR, IGDR
  • Level-3: Along-track Absolute Dynamic Topography
  • Level-4: Gridded Absolute Dynamic Topography 

Further information:

• Jason-3 video: Meteorology and rogue waves 
• Applications: Atmopshere, winds and waves
• News, Category Ocean and climate news
  • Winter high waves in North Atlantic
  • Strong swell in french Polynesia on June 2013

• The along-track Absolute Dynamic Topography Heights (ADT-H) in Near-Real-Time have a new dataset j3.
• For the gridded products Heights and currents (MADT-H, MADT-UV and MSLA-UV) in Near-Real-Time: Jason-3 mission turns into the new reference mission and replaces Jason-2 in the multi-mission merged maps.

From its highly inclined 1,336-kilometre orbit, Jason-3 covers 95% of the globeâs ice-free oceans every ten days. Planned to operate for three years with a possible extension to five years, it will assure the data continuity so vital to effective monitoring of global warming through to at least 2021, before being joined by two other satellites, Jason-CSA/Sentinel-6A and Jason-CSB/Sentinel-6B.

Developed by CNES and Thales Alenia Space, Jason-3 is built around a Proteus spacecraft bus. It is carrying a Poseidon-3B altimeter, the main mission instrument that measures the range from the satellite to the ocean surface, an advanced microwave radiometer (AMR) to measure emitted radiation, a CNESdesigned DORIS orbit determination system, a GPS payload (GPSP) and a laser retroreflector array (LRA) developed by NASA/JPL. It is also carrying the CARMEN 3/AMBRE instrument supplied by CNES and the Light Particle Experiment supplied by the Japan Aerospace Exploration Agency (JAXA), which will be tasked with characterizing the satelliteâs radiation environment.  

Map comparing significant wave heights measured by Jason-2 and Jason-3 measured on 2016/01/19, few hours after the altimeter was switched on. Credits CNES.

Further information:

• Missions: Jason-3