Abstract's details
Sentinel-6 MF & Sentinel-6B calibration at the Bass Strait, Corsica and Harvest facilities
Event: 2026 Sentinel-6 Validation Team meeting
Session: S6VT plenary session
Presentation type: Oral
- Bass Strait facility
The Bass Strait altimeter validation facility (~40° 39’S, 145° 36’ E) continues to provide cycle-by-cycle estimates of altimeter absolute SSH bias for the TOPEX - Jason - Sentinel-6 reference missions, in addition to Sentinel-3A and Sentinel-3B, each with dedicated comparison points. The facility uses a direct geometric approach to validation that involves maintaining an in situ network of sensors including moored oceanographic instruments, GNSS equipped buoys, a coastal tide gauge and continuously operating GNSS reference stations.Here we present our evaluation of the first Sentinel-6B data. We utilise the latest in situ data until March 2026 to enable a first evaluation of Sentinel-6B over the Bass Strait facility. We also present our analysis of the Jason-3 / Sentinel-6 Michael Freilich missions, presenting absolute and relative SSH biases for each respective mission.
- Corsica facility:
Initially developed for monitoring the performance of TOPEX/Poseidon and follow-on Jason/Sentinel-6 legacy satellite altimeters, the Corsica geodetic facilities that are located both at Senetosa Cape and near Ajaccio have been developed to calibrate successive satellite altimeters in an absolute sense. Since 1998, the successful calibration process used to calibrate most of the oceanographic satellite altimeter missions has been regularly updated in terms of in situ instruments, geodetic measurements and methodologies.
Launched in November 2025, Sentinel-6B will replace Sentinel-6 Mickael Freilich as the reference mission after its commissioning which will last about one year. In this presentation we will show preliminary results on the SSH bias differences as well as details on their origin, obtained during the first months of the Formation Flight Phase of the two satellites. This analysis will be based on NRT and STC products before being officially released to word wild users.
- Harvest facility:
We provide updated results from the Harvest experiment, focusing on efforts to extend the vital 33-yr record to include the recently launched Sentinel 6B mission. With the decommissioning of the Harvest platform systems in October 2022, the experiment has entered a new phase which leverages an innovative regional array of in-situ measurement resources, while still maintaining the platform location as the fiducial reference point. The centerpiece of the current measurements is a new tide gauge, collocated with a nearby permanent GNSS station, at the Vandenberg Space Force Base boat dock. Installed by University of Hawaii under the auspices of NOAA, the radar gauge is located about 10 km from the platform along the same ground track that passes by the platform. Within a 1-km radius of the platform locations are advanced GNSS buoys which are replenished on a rotating basis (2X per year) to maintain continuous coverage. Additional observing assets, most notably a dual-frequency radar transponder, are located on Catalina Island along the adjacent Sentinel-6 ascending repeat track.
Based on early results (5 overflights), the Sentinel-6B SSH bias is statistically indistinguishable from zero (+4 ± 13 mm) at Harvest. The much longer Sentinel-6 Michael Freilich (MF) calibration record continues to grow and reveals an SSH bias of +17 ± 3 mm based on 131 overflights for the currently operating Side B radar altimeter. We also provide new results for the SWOT mission, which passes within ~3 km of the platform in tracing out its 21-d repeat ground track, and for the legacy TOPEX/Poseidon mission based on newly reprocessed (GDR-F) altimeter data products.
The Bass Strait altimeter validation facility (~40° 39’S, 145° 36’ E) continues to provide cycle-by-cycle estimates of altimeter absolute SSH bias for the TOPEX - Jason - Sentinel-6 reference missions, in addition to Sentinel-3A and Sentinel-3B, each with dedicated comparison points. The facility uses a direct geometric approach to validation that involves maintaining an in situ network of sensors including moored oceanographic instruments, GNSS equipped buoys, a coastal tide gauge and continuously operating GNSS reference stations.Here we present our evaluation of the first Sentinel-6B data. We utilise the latest in situ data until March 2026 to enable a first evaluation of Sentinel-6B over the Bass Strait facility. We also present our analysis of the Jason-3 / Sentinel-6 Michael Freilich missions, presenting absolute and relative SSH biases for each respective mission.
- Corsica facility:
Initially developed for monitoring the performance of TOPEX/Poseidon and follow-on Jason/Sentinel-6 legacy satellite altimeters, the Corsica geodetic facilities that are located both at Senetosa Cape and near Ajaccio have been developed to calibrate successive satellite altimeters in an absolute sense. Since 1998, the successful calibration process used to calibrate most of the oceanographic satellite altimeter missions has been regularly updated in terms of in situ instruments, geodetic measurements and methodologies.
Launched in November 2025, Sentinel-6B will replace Sentinel-6 Mickael Freilich as the reference mission after its commissioning which will last about one year. In this presentation we will show preliminary results on the SSH bias differences as well as details on their origin, obtained during the first months of the Formation Flight Phase of the two satellites. This analysis will be based on NRT and STC products before being officially released to word wild users.
- Harvest facility:
We provide updated results from the Harvest experiment, focusing on efforts to extend the vital 33-yr record to include the recently launched Sentinel 6B mission. With the decommissioning of the Harvest platform systems in October 2022, the experiment has entered a new phase which leverages an innovative regional array of in-situ measurement resources, while still maintaining the platform location as the fiducial reference point. The centerpiece of the current measurements is a new tide gauge, collocated with a nearby permanent GNSS station, at the Vandenberg Space Force Base boat dock. Installed by University of Hawaii under the auspices of NOAA, the radar gauge is located about 10 km from the platform along the same ground track that passes by the platform. Within a 1-km radius of the platform locations are advanced GNSS buoys which are replenished on a rotating basis (2X per year) to maintain continuous coverage. Additional observing assets, most notably a dual-frequency radar transponder, are located on Catalina Island along the adjacent Sentinel-6 ascending repeat track.
Based on early results (5 overflights), the Sentinel-6B SSH bias is statistically indistinguishable from zero (+4 ± 13 mm) at Harvest. The much longer Sentinel-6 Michael Freilich (MF) calibration record continues to grow and reveals an SSH bias of +17 ± 3 mm based on 131 overflights for the currently operating Side B radar altimeter. We also provide new results for the SWOT mission, which passes within ~3 km of the platform in tracing out its 21-d repeat ground track, and for the legacy TOPEX/Poseidon mission based on newly reprocessed (GDR-F) altimeter data products.
Contribution: S6VTP2026-Sentinel-6_MF___Sentinel-6B_calibration_at_the_Bass_Strait__Corsica_and_Harvest_facilities.pdf (pdf, 11155 ko)
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