ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. Göttingen, Germany 10.5194/essd-2026-809 GESLA Version 4: Further Enhancements to the Global Higher-Frequency Sea-Level Dataset Haigh Ivan 1 2 Marcos Marta https://orcid.org/0000-0001-9975-5013 3 Talke Stefan A. https://orcid.org/0000-0002-7961-3306 4 Carneiro-Barros Jose E. 1 2 Hague Ben S. 5 Thompson Philip 6 Wilson Samuel 6 Nagaraj Meghana 1 2 Beemster Joris G. W. https://orcid.org/0000-0002-3178-6689 7 Kenwright Christian 8 Martin Ariadna 1 2 Quadrado Gabrielle https://orcid.org/0000-0001-5714-6770 1 2 Wahl Thomas 1 2 Hart-Davis Michael G. https://orcid.org/0000-0001-9342-0335 9 Department of Civil, Environmental and Construction Engineering, University of Central Florida, Orlando, FL, USA Center for Integrated Coastal Research, University of Central Florida, Orlando, FL, USA IMEDEA (UIB-CSIC), 07190 Esporles, Balearic Islands, Spain Department of Civil and Environmental Engineering, California Polytechnic State University, San Luis Obispo, California, USA Australian Bureau of Meteorology, GPO Box 1289, Melbourne, Victoria, Australia Department of Oceanography, University of Hawaiʻi at Mānoa, Honolulu, Hawaiʻi, USA Department of Environmental Sciences, Wageningen University and Research, Wageningen, The Netherlands School of Ocean and Earth Science, University of Southampton, European Way, Southampton, SO14 3ZH, UK Deutsches Geodätisches Forschungsinstitut, Technische Universität München, Munich, Germany 28 10 2026 2026 1 34 Copyright: © 2026 Ivan Haigh et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://essd.copernicus.org/preprints/essd-2026-809/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2026-809/essd-2026-809.pdf

This paper presents GESLA-4, the latest major update to the quasi-global, higher-frequency sea-level dataset known as GESLA (Global Extreme Sea Level Analysis). Since its first release in 2009, GESLA has become a widely used observational resource for investigating tides, storm surges, extreme sea levels, and other coastal and oceanographic processes, supporting numerous published studies and major national and international assessments, including assessment reports of the Intergovernmental Panel on Climate Change. GESLA-4 represents a substantial expansion of the dataset, containing 136,069 station-years of observations across 6,682 records obtained from 43 international, national, and regional data sources. This represents an increase of 45,048 station-years and 1,563 records relative to GESLA-3. In addition to extending existing records and incorporating new data sources, GESLA-4 includes improvements to data processing and consistency, including a systematic review of record time zones. Data accessibility has also been enhanced through programmatic access via an Environmental Research Division's Data Access Program (ERDDAP) server and direct download links for individual stations via Amazon Web Services. This paper describes the assembly, processing, format and accessibility of GESLA-4, and also examines how the dataset has evolved across its four releases since 2009, and reviews how its scientific use has grown and diversified. GESLA-4 provides an extensive and readily accessible observational resource for investigating coastal sea levels, their variability and extremes, and their response to a changing climate.