Direct Ocean Tidal Current Measurements From Space: Enhanced Interpretation of Sentinel-1 Doppler Shift Signals

Advances in Sentinel-1 Doppler processing have continued to unlock deeper understanding of surface current dynamics. With future missions emphasizing total surface currents observations, the resolving of processes will grow, including tidal currents. Tidal currents themselves are an interesting dynamical feature, but the modeling of tidal currents will become increasingly valuable to account for their contribution to the total surface currents. This study uses radial velocities from Sentinel-1 Doppler observations to derive tidal currents. The North Sea is a region of strong tidal variability, with tidal heights reaching 10 s of meters. It is, therefore, a suitable natural laboratory to test tidal current retrievals from the radial velocity observations. Results indicate a strong correlation with global tidal current models, TPXO10.2 and FES2014b, for estimated tidal constituents. The results indicate the potential of resolving tidal currents from Sentinel-1, which will advance modeling efforts in terms of both validations and possibly data assimilation.