Waves breaking on sea wall. Credit: Zacarias da Mata

New evolution of Sentinel-3 Altimetry products


Waves breaking on sea wall. Credit: Zacarias da Mata
Waves breaking on sea wall. Credit: Zacarias da Mata

A new Sentinel-3 Altimetry Processing Baseline (PB): SM__WAT.005.02, an updated PB of Baseline Collection (BC) 005, has been released.

Last Updated

08 March 2023

Published on

23 February 2023

The Processing Baseline (PB) SM__WAT.005.02 is an update to the recent Baseline Collection 005 (BC 005). It provides an update of the mean values of the geophysical retrievals Sea Level, Wind and Waves, keeping the same quality as the rest of BC005. This PB will be used on the ongoing full mission reprocessing.

This PB brings several relevant evolutions and anomaly fixes to the Sentinel-3 Altimetry Marine Products.

The updates affect mostly Level-2 products. For the Level-1, there has been an update of the processors, without any user impact.

The PB will enter into operations on 9 March 2023.

Note the new PB naming convention, that makes the PBs within the same processing change continuous:

  • SM__WAT.005.02.00 (SRAL/MWR L2 Marine)
  • SR__L1M.005.01.00 (SRAL L1 Marine)
  • MW__L1_.005.01.00 (MWR L1 Global)

The first seven characters refer to the processing chain/product type, followed by the Baseline Collection, then the processing baseline (incremental), and finally, the patch number (incremental). All the fields are separated by a point. This information is now part of the products (both netCDF and manifests).

List of changes

SRAL/MWR L2 (v7.03)

  • Update of mean values for SSHA (and its corrections) and SWH and Wind Speed.
  • Application of GPD+ Wet Tropospheric Correction (WTC) to SSHA (NTC only).
  • Addition of Wind Speed calculated from Sigma0 and SWH (like Sentinel-6).
  • Addition of quality flags for SSHA, SWH, Wind (at 1Hz measurement level)
  • Update of the 1Hz data generation method, to include strict MQE screening — preventing bad 20Hz data to be used on 1Hz
  • Addition of information (in the netCDFs) about the bias applied in the L2 products.
  • Addition of sea ice concentration information at 1Hz.
  • Addition of SRAL acquisition mode at 1Hz.
  • Addition of information regarding the WTC applied to build the SSHA.
  • Correction of the geoid (EGM2008) since the version used previously on the product had an error.
  • Elevation from sea-ice/ocog retrackers now uses high frequency dynamic atmospheric pressure correction.
  • Correction of S3B cycle number on the first pass of the cycle — netCDF only.
  • Improved radiometer quality flag, especially during lunar calibration events.

SRAL L1 (v6.24)

  • New version has no impact on users.

MWR L1 (v6.14)

  • New version has no impact on users.
Example of Sentinel-3A SRAL wind speed
Figure 1: Altimeter wind speed derived from 2 parameter algorithm

Overall impact

Detailed impact on Sea Level, Winds and Waves provided within the Product Notice.


Product Notice

Updated Product Format specification.

For more information, contact our User Service Helpdesk.