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16.03.2023 14:40 Age: 1 year

GMSL Update: integration of Sentinel-6 Michael Freilich

Category: Website updates

The Aviso global mean sea level (GMSL) time series has been recently updated with the Sentinel-6MF mission

Reference global mean sea level (GMSL) from January 1993 to present, after removing the annual and semi-annual signals and applying a 6-month filter. Postglacial rebound correction is applied. Credits CNES/LEGOS/CLS.

The reference GMSL is determined by using the TOPEX/Poseidon, Jason-1, Jason-2, Jason-3 and Sentinel-6MF missions from January 1993 to February 2023, after removing the annual and semi-annual signals and applying a 6-month filter and the postglacial rebound correction (-0.3 mm/yr).
The rise in GMSL is thus estimated to 3.6 mm/year (with an uncertainty of 0.3 mm/yr) since 1993.
All information available at https://www.aviso.altimetry.fr/msl 
Note that:
- The Jason-3 / Sentinel-6MF intermission bias of -0.21 cm has been applied. Indeed, to ensure the accuracy of the long-term GMSL estimates, calibration phases between successive missions (called tandem phases) are performed to estimate their relative measurements biases. These biases are computed as the mean difference of the GMSL measurements between the two successive missions while they fly in tandem. Detailed information are available at https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/processing-and-corrections.html 
- The GMSL estimate takes into account the Sentinel-6 MF inaccurate radiometer calibration error over the last quarter of year 2022 resulting in an overestimation of the wet tropospheric correction, affecting the GMSL estimate by about 5 mm during that period.