The present version of the product includes data from 725 tide gauges, covering the European coast in great detail, and for the generation of this new reprocessing product we have worked with a total of 1048 time series, including series with their original sampling (1-min , 15-min, etc.) and resampled ones (in hourly frequency), both for the astronomical tide and for the sea level residual.

>>> Distribution and time series coverage (in years) of the 725 tide gauges, included in the reprocessing product. Source: Copernicus Marine Service.

In addition, a homogeneous quality control has been carried out using SELENE. This software, originally developed in Puertos del Estado (Pérez-Gómez, 2015) has been evolved by NOW Systems since 2022, being added the following functionalities:

• Adaptation of the tidal residual calculation (existing in previous versions but not used in near-real time) for its use in the reprocessing.
• Implementation of a new module for comparing hourly tidal residuals, the monthly average of total sea level, and attenuated signal detection.
• Homogenization of the parameter assignment criteria used by SELENE for quality control at each station (including maximum possible ranges; the level of the polynomial to adjust in peak detection, window size for adjustment and number of tolerable standard deviation).

The current version of the software can detect, automatically and easily, erroneous sea level measurements, homogenizing criteria and reducing the expert review.

>>> Example of the automatic Quality Control implemented (automatic marking of bad data (red) and good data (blue).

It is worth noting the importance that this new reprocessed product based on these historical timeseries with homogeneous quality control criteria has, providing to the scientific community with robust information for subsequent climate and trend analyses.

For more details about the technical-scientific description of this product and the software developed, see the publication in Ocean Science (Lin-Ye et al. (2024).