Anomalies

Anomalies identified by the Sentinel-6 Calibration and Validation team are listed in the table below by cycle. All data granules from cycles with known anomalies are considered "unvalidated." Each L2 non time-critical (NTC) product from Sentinel-6 has a corresponding "unvalidated" dataset from which such granules may be obtained.

Processing Baselines

April 2025: Processing Standard Updated from F09 to G01

The new baseline collection G01 is adding a major improvement to both LR and HR with incorporation of the Geophysical Data Record, Version G (GDR-G) standards, which aim to harmonize auxiliary files in use by all altimetry European operators a set of common auxiliary data have been defined by all partner agencies to facility the work of our user community. The new auxiliary data include:

• Updated Mean Sea Surface models
• Updated Mean Dynamic Topography Model
• Updated Finite Element Solution (FES) Ocean Tide Model (to FES 2022b)
• Improved orbit solution
• New Method for Land and Environment (MLE) 4 correction tables

Additional improvements introduced with the G01 processing baseline:

• Adds C band complex echoes in Level 1A altimetry products when the POS4 is acquiring data in RAW mode. Note that C band complex echoes are not telemetered when the Poseidon-4 radar altimeter (POS4) is in Range Migration Correction (RMC) mode.
• Removes MLE3 variables from Level 2 products.
• Adds Vertical Wave Motion (VWM) correction at 20Hz for NR HR, and for SAR Altimetry Studies and Applications (SAMOSA) in Level 2 products.
• Resolves anomalies as described in Section 6 of the Release Note.

April 2024: Processing Standard Updated from F08 to F09

Baseline collection F09 added a few minor corrections to the LR processing chain and several major improvements to the HR processing chain:

• Addressed anomalies to the LR chain, and corrected a few characterization scaling factors that considerably reduce the biases of sigma_0 when comparing to Jason-3 and Sentinel-6 Michael Freilich HR.
• Addressed anomalies to the HR chain.
• Added range Walk in the Level 1 HR to account for the variation of range between the instrument and a given scatter during the total illumination time.
• Added the HR NR to the Level 2 altimeter data to better account for instrument drifts in HR.
• Added Significant Wave Height (SWH) improvements to the HR chain through the correction of Vertical Wave Motions effects, and included wave modeled information in the Level 2 altimeter products for LR and HR.
• Added High-Resolution Microwave Radiometer (HRMR) variables into the Level 2 altimetry products: LR and HR.

The F09 processing baseline was introduced in forward stream starting in April 2024 and was not accompanied by full reprocessing of the Sentinel-6 data record. Users should continue accessing short time critical (STC) and NTC altimetry products from the datasets released upon completion of F08 reprocessing in July 2023.

February 2023: Processing Standard Updated from F07 to F08

Processing baseline F08 incorporates new data derived from a Numerical Retracker. Reprocessed data include the following improvements:

• Poseidon-4 antenna beamwidth correction from 1.33 to 1.34 based on in-flight calibration.
• Change in the scaling factor used to compute the total electron content from the dual band ionospheric correction.
• The addition of the LR, Ku-band, Numerical Retracker (NR) in the altimeter Level 2 products.

This reprocessing also brings corrections for missing files and anomalies affecting a small number of passes in the F06/F07 NTC products.

July 2022: Processing Standard Updated from F06 to F07

NTC products were transitioned to processing baseline F07 at cycle 65. Processing baseline F06 is used for cycle 04 through cycle 65, pass 20. Processing baseline F07 is used from cycle 65, pass 21 onward. The new F07 baseline adds a number of further improvements: 

• The availability of HRMR data in all radiometer products, extending the wet path delay measurements into coastal areas, with a performance goal of 1.0 cm accuracy within 5-50 km from the coast.
• The usage of ECHO CAL as main source of CAL1, thus removing any impacts to Sea Surface Height Anomaly (SSHA) retrievals from variations of internal path delay around the orbit.
• The introduction of a forecasted dynamic atmospheric corrections (MOGF) in L2 near real-time (NRT) production, improving the NRT SSHA accuracy and crossovers differences. 

August 2022: Initial NTC Data Released under F06 Processing Standard

• Sentinel-6/Michael Freilich Reprocessing Updates: Version 2 Completed, Version F Retired

Reference Documents