New Sentinel-3 SRAL Processing Baseline

The SRAL L1 and L2 Processing Baseline 2.27 will be released on 14 February.

Thursday, 08 February 2018

New SRAL Processing Baselines

The following changes will be made:

SRAL Level 1

Update of on-ground calibration strategy:

  • The applied CAL2 calibrations will have an average time window of the previous 27 days. Before the IPF was just averaging 10 days.
  • An averaged (27 days) CAL2 filter mask will now be applied to CAL1 Point Target Response (PTR).
  • The Ku-Band CAL2 filter mask will now be applied to C-Band data and CAL1 PTR.

These changes will improve the data quality and reduce the noise.

SRAL/MWR Level 2:

Bug fix:

  • Overflow corrected for Peakiness and Mean Quadratic Error (MQE) parameters.
  • Other run time anomalies.


  • The SAR retrieved Significant Wave Height (SWH) will now be calculated directly from SAMOSA retracker outputs, bypassing the sigma_c calculation. This is expected to improve SWH retrievals below 1 meter SWH.
  • Addition of Elevation derived from OCOG retracking.

In addition, an error in the computation of the ANX time leads to an error of up to 8 seconds in the equator crossing time, affecting L0 up to L2 data. This ANX value is used internally to generate the start/stop times of the pole to pole passes (STC and NTC) which has been improved with PB 2.27. A final resolution is expected in the near future.

More information can be found in the Sentinel-3A Product Notice – Altimetry (PDF, 1 MB), Sentinel-3A Product Notice – STM L2 Marine (NRT, STC and NTC) (PDF, the 798 KB) and the Product Data Format Specification - SRAL/MWR Level 2 Marine products (PDF, 2 MB).

For more information, contact our User Service Helpdesk.

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