The twin field experiments C-SWOT-2023 and WEMSWOT  were carried out in March-April 2023 and aimed to support the new-generation SWOT altimeter (NASA/CNES) calibration and validation. This satellite provides a measurement of sea surface elevation and rugosity with unequalled space-time coverage, particularly during its intensive observation phase from March to June 2023. The originality of this field experiments is the mobilisation of two research vessels (the R/V Thetys II for C-SWOT-2023 and the R/V Atalante for WEMSWOT)  that sailed along together to explore statistics of the surface ocean dynamics (vorticity, strain, divergence) that are seldomly accessible in fine scale observations. Common transects recording at least velocities, temperature and salinity in the four hundred metres under the surface were performed in order to disentangle the geostrophic and the ageostrophic part of the circulation. To complete this approach, an intensive lagrangian experiment was also performed using Carthe or WOCE drifters and direct measurements of sea surface height using GNSS have been tried out. At the end of the cruise the potential of an unmanned surface vehicle for oceanography (the DRIX) was tested during 5 days to catch the North Current variability and related small scale variability.

The poster provides an overview of the work carried out during the cruises and the initial results.