“…Satellite altimetry has made these, and other achievements, possible because it has provided continuous sea-level observations over large parts of the ocean, in areas where sea-level measurements were previously only occasional.While invaluable over the open ocean, satellite altimetry measurements have historically been flagged as unreliable within 20-50 km from the coast (e.g., Benveniste et al, 2020). Indeed, the accuracy of radar altimetry, which is 2-3 cm over the open ocean (e.g., Volkov and Pujol, 2012), deteriorates in coastal regions because of technical issues (e.g., Xu et al, 2019).Notably, land contaminates the returned echoes of radar altimeters, and the complex topography of continental shelves, together with the irregular shape of most coastlines, makes geophysical corrections in coastal areas less accurate than in the open ocean. To increase the accuracy of radar altimetry in coastal regions, Passaro et al (2014) have developed the Adaptive Leading Edge Subwaveform (ALES) retracking algorithm.…”