Design and regional assessment of an empirical tidal model based on FES2014 and coastal altimetry

The updated Empirical Ocean Tide model (EOT19p) currently available on limited regions is presented in this paper. Its implementation is focused on improving the accuracy of tidal estimation at the coast. EOT19p is derived using circa 27 years of coast-dedicated altimetric data and the FES2014 tide model, and it is based on a multi-mission, weighted least-squares approach. In this work the performance of EOT19p is assessed with respect to state-of-the-art tide models against in situ observations. The study is performed on two critical regions: the North Sea and the Malay Archipelago. Comparisons for eight major tidal constituents show that EOT19p improves coastal results with respect to its former version, EOT11a, of 35.39% in the North Sea and 20.07% in the Malay Archipelago, with large error reduction in the English Channel and the Irish Sea. The median absolute differences (MAD) against in situ data show that EOT19p is in line with the latest models, with lowest error occurring for single tidal constituents, such as M2 (with a MAD of 1.63 cm in the Malay Archipelago). Finally, the tidal height differences of three models (EOT19p, FES2014, and DTU16) compared with those obtained of their former versions (EOT11a, FES2012, and DTU10), show an increased agreement at coastal areas with the latest versions, and the regional average difference for M2 constituent drops from 3.75 cm to 0.70 cm in the North Sea, and from 3.02 to 1.44 cm in the Malay Archipelago.