SHELDA: sub-hourly European quality controlled sea level dataset

Abstract

Freely accessible sea level databases often contain time series measured with hourly or even longer sampling step, or they contain high-frequency data that have not undergone quality control procedures. To address this gap, the SHELDA (Sub-Hourly European Quality Controlled Sea Level DAtaset) has been created. This dataset comprises 257 individual tide gauge records in NetCDF format (https://doi.org/10.14284/764, Balić and Šepić, 2025), each representing quality-controlled sea level time series sampled at intervals between 1 and 15 min, along with residual time series derived by removing tidal components. The duration of individual records ranges from a minimum of one month to a maximum of 13 years. This manuscript outlines the rigorous quality control procedures (i.e., removal of out-of-range values, application of an automatic spike detection algorithm, visual inspection) implemented and discusses the procedures that were not implemented (i.e., corrections of datum shifts). The manuscript further describes the spatial and temporal coverage of the dataset, along with technical specifications. All data are distributed under the CC BY 4.0 licence. SHELDA enables precise identification and analysis of sea level variability at timescales ranging from minutes to seasonal and longer, depending on the stability of the long term series along the European coasts and along the coasts of Greenland, Canary Islands, Israel, Lebanon and Türkiye.