News

07.10.2020 09:48 Age: 49 days

[Jason-3] GDR-F Announcement

Category: News of the Jason -3 mission

We are pleased to inform you that the Jason-3 GDR standard will upgrade to GDR-F on 2020 October, 29th

GDR -F will become the operational baseline standard for Jason -3 OGDR and IGDR (from cycle 174 onwards) and GDR (from cycle 171 onwards) 

The Jason -3 GDR -F standard, following OSTST recommendations, includes many improvements compared with the previous GDR -D Standard among which :

 

  • 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 :

 

 

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 productionGDR -D” and “ GDR -F” 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