Ocean surface A Spot

Past Sentinel-3 altimetry processing baselines


Ocean surface A Spot
Ocean surface A Spot

Timeline and overview of previous Copernicus Sentinel-3 SRAL/MWR processing baselines.

Last Updated

16 February 2023

Published on

14 January 2020


Obsolete baseline collection 003

Baseline collection 003 PB 2.27 PB 2.33/1.13* PB 2.45
IPF versions SRAL L1 (SR-1): 06.13
MWR L1 (MW-1): 06.04
SRAL/MWR L2 (SM-2): 06.12
SRAL L1 (SR-1): 06.14
MWR L1 (MW-1): 06.07
SRAL/MWR L2 (SM-2): 06.14
* PB1.13: same IPF versions; it only includes some static Auxiliary Data Files (ADFs) which are specific to S3B
SRAL L1 (SR-1): 06.16
MWR L1 (MW-1): 06.09
SRAL/MWR L2 (SM-2): 06.15
Product notice L1 PN (2.27)
L2 PN (2.27)
L1 PN (2.33)
L2 PN (2.33)
L1 PN (2.33/1.13)
L2 PN (2.33/1.13)
L1 PN (2.45)
L2 PN (2.45)
PB deployment date (NRT) 14/02/2018 04/04/2018 (S3A, PB2.33)
06/12/2018 (S3B, PB 1.13)
Dataset (NTC)
(sensing time & server)
“Spring 2018”
From: 01/03/2016
To: 12/02/2018
Data Store
Operational NTC
From: 19/01/2018
To: 09/03/2018
Operational NTC
From: 09/03/2018
To: 20/01/2019
Operational NTC
From: 20/01/2019
To: Current
Manifest file   ANX information is more accurately computed. Correction of spurious gaps being reported on the manifest, due to the application of the land-sea mask.
Tide models      
Backscatter coefficient      
SWH SAR SWH calculated directly from SAMOSA retracker outputs, bypassing the composite sigma (sigma_c)   Update of LUT to improve SWH w.r.t. ECMWF’s model.
Sea ice     Major improvement in sea retrievals and freeboard.
Wet tropo      
Dry tropo   Correction of 5mm bias IR with respect to z.  
New parameters Elevation derived from OCOG retracking [elevation_ocog_20_ku]: expected to be useful near the coast, on icy surfaces and inland water bodies (such as the Great Lakes and Lake Victoria).
Geophysical corrections are applied to this field.
Other fixes or changes in the PBs
  • Overflow corrected for peakiness and MQE parameters.
  • The number of stack beams is increased from 174 to 180. This will employ all the useful beams in the stack.
  • The satellite platform attitude angles are no longer invalid during manoeuvres.
  • Fixed issue related to 1Hz data without associated 20Hz measurements.
  • Sea-ice/ice noise gate power calculation is now correct.
  • Correction _FillValue is properly handled for Sea Ice SSHA.
Corrected C Band longitude and latitude:
Corrected LRM variables:
[sea_ice_concentration_20_ku] [snow_depth_20_ku]

*PB 1.13 (S3B): Correction of issues noted during S3B commissioning:

Bias is sigma0 w.r.t. to S3A in Ku and C bands
(this generated incorrect wind speed retrieval and incorrect flagging of rain).
Fine tuning of the MWR brightness temperatures in order to align it to S3A
(a few millimeters difference was visible in the radiometer wet tropospheric correction —now corrected).
  • Orbit type variable is now correctly set when orbit information comes from NAVATT
  • Update of variable comments on the netcdf to better reflect the data
  • Acquisition station is now also reported in the netcdf
Changes to ground segment or spacecraft 18/12/2017: New zone database used in operations to avoid small (sub/seconds) data gaps near the Greenwich meridian. 01/03/2018: New MWR calibration strategy reduces the number of occasions where the MWR values are set to default.
28/05/2018: Improved orbit quality in STC: since the STC orbits have been generated by CNES/SALP using GNSS data, as well as DORIS data. This allows for better orbit quality and fewer differences when comparing to the NTC orbits.
10/11/2018: Updated standard for CNES orbits (POE-F): since cycle 38 of S3A (STC and NTC) the orbits solutions generated by CNES/SALP use the new standard POE-F.
20/09/2018: Improved cut of the pole to pole pass (and pass numbering and ANX crossing time): the information on when to cut to the pole to pole passes (STC and NTC) is derived from several system components that were fixed at different points in time. Since 20/09/2018 the situation has been completely fixed for L1 and L2. The reprocessed dataset (up to 20/01/2018) is correct.
27/11/2018: Improved data quality at pass transition (STC and NTC): the data present in L1/L2 passes had a degradation at pass transition, due to the fact that adjacent granules were not provided to the processor. This degradation has been
corrected since 27/11/2018.
17/01/2019: The KREMS safe zone (around the KREMS radar facility) has been enlarged to 300 Km to avoid any damaged to the MWR instrument. This is applicable to S3A and S3B. In this safe zone the radiometer is disabled and, thus, there is no wet tropospheric correction available from the radiometer, causing the SSHA to be set to a default value.
28/05/2019: The KREMS safe zone has been reduced from 300km to 100km radius.

For a complete list of changes, please consult the product notices listed above.

For the current summary table, see current altimetry processing baselines.