ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. 1866-3591 Göttingen, Germany 10.5194/essd-2026-232 OceanTACO: A Multi-Sensor Global Ocean Sea Surface State Dataset Lehmann Nils https://orcid.org/0000-0002-3142-0783 1 2 Aybar Cesar 3 Shah Ando https://orcid.org/0009-0009-4010-6954 4 Passaro Marcello https://orcid.org/0000-0002-3372-3948 5 Bamber Jonathan L. https://orcid.org/0000-0002-2280-2819 6 7 Zhu Xiao Xiang https://orcid.org/0000-0001-5530-3613 1 2 Data Science in Earth Observation, Technical University of Munich (TUM), 80333 Munich, Germany Munich Center for Machine Learning (MCML), 80333 Munich, Germany Image Processing Lab (IPL), University of Valencia, 46980 Valencia, Spain School of Information, University of California, Berkeley, Berkeley, CA 94720, USA Deutsches Geodätisches Forschungsinstitut (DGFI-TUM), Technical University of Munich (TUM), 80333 Munich, Germany School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK Institute for Advanced Study, Technical University of Munich (TUM), 80333 Munich, Germany 10 04 2026 2026 1 35 Copyright: © 2026 Nils Lehmann 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-2026-232/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2026-232/essd-2026-232.pdf

We present OceanTACO, a harmonised global collection of sea surface state datasets designed to support reproducible Earth system research. The collection integrates satellite altimetry, sea surface temperature, salinity, surface winds, reanalysis fields, and Argo in situ observations within a unified cloud-optimised specification based on Transparent Access to Cloud-optimised datasets (TACO). It includes Level-3 observations, Level-4 gap-filled products, and reanalysis outputs while preserving native spatial and temporal resolution. The core dataset spans 29 March 2023 to 1 August 2025, covering the Surface Water and Ocean Topography (SWOT) mission, with an extended record from 1 January 2015 until 29 March 2023 for non-SWOT sources.</p> <p>Datasets are harmonised through standardised metadata, spatial referencing, and temporal indexing, enabling consistent spatiotemporal queries across sensors and processing levels. A uniform internal structure reduces product-specific preprocessing and allows the same data-access routines to be applied across regions, sensors, and studies. This supports Earth systems analyses workflows such as validation against in situ observations, comparisons between observation and mapped products, observation system experiments, and multivariate sensor analyses.</p> <p>Example applications demonstrate cross-product collocation with Argo, analysis of sea surface height variability during extreme events, and relationships between surface variables relevant for data-driven reconstruction. OceanTACO improves accessibility to coordinated multi-source analyses while preserving data provenance and native observation characteristics, and can be extended with new missions without restructuring the dataset. The core and extended dataset are available at <a href="https://doi.org/10.57967/hf/8171" target="_blank" rel="noopener">https://doi.org/10.57967/hf/8171</a> (Lehmann and Aybar, 2026a) and <a href="https://doi.org/10.57967/hf/8172" target="_blank" rel="noopener">https://doi.org/10.57967/hf/8172</a> (Lehmann and Aybar, 2026b) respectively.

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