F. Lyard (LEGOS, France); M-L Dabat (CLS, France); M Tchilibou (CLS, France); E Fouchet (NOVELTIS, France); Y Faugère (CLS, France); G Dibarboure (CNES, France)

Thanks to its current accuracy and maturity, altimetry is considered as a fully operational observing system dedicated to various applications such as climate studies. Altimeter measurements are corrected from several geophysical parameters in order to isolate the oceanic variability and the tide correction is one of the most critical. The Dynamic Atmospheric Correction (DAC) is the second most important one after the tide correction. The accuracy of both tide and DAC models has been much improved for last 25 years leading to centimetric accuracy in the open ocean.

To address the reduction of remaining errors in shelf/coastal seas and at high latitudes and to face the new challenges of the tide correction for HR altimetry, in particular the new SWOT mission, a new global tide model FES2022 has been developed.
This new tidal solution uses higher spatial resolution in coastal areas, extending systematically the model mesh to the narrowest coastal systems (fjords, estuaries, …), and the model bathymetry has been upgraded in many places thanks to an international collaboration effort. The hydrodynamic modelling benefits also from further improvements which allows producing very accurate hydrodynamic simulations. The use of the most recent altimeter standards and high inclination altimeters like Cryosat-2, Saral/AltiKa and even Sentinel-3, also allowed retrieving some tide observations in the highest latitudes to help improving the polar tides modelling. A new loading tide solution has also been produced. Validation results show a great improvement of the FES2022 both hydrodynamic and assimilated solutions compared to FES2014. Recent validation results of FES2022 tidal solution in coastal areas are presented here. Some comparisons with the first SWOT 1-day dataset are also proposed.

Concerning the DAC, a new model version has been developed and is producing optimized data since end of August 2023; improvements of version V4.0 are mostly visible in shallow waters. Some tests using coupled surge and tides simulations are also currently performed and preliminary results will be presented.