Drifters trajectories give information about the actual forces acting within the ocean, providing currents and accelerations, as well as the divergence/convergence when deployed in groups. They have proven their worth for the surface submesoscale dynamic estimation  and can thus complete the understanding of the dynamic we have from altimetry. Historical database (GDP) and alongtrack altimetry allow us to examine the surface momentum balance. Data from C-SWOT2023  and BioSWOT-Med field experiments will be also considered.