05a92176-c60d-4579-8c14-a9cc01383fdd pointOfContact 2026-09-22T09:23:55.204484Z ISO 19115-3:2018 - Remote Sensing ISO 19115-3:2018 - Remote Sensing 1.0 http://www.opengis.net/def/crs/EPSG/0/4326 Sentinel-6 Delay-Doppler Altimetry retracking 5 parameters product 2026-06-10 creation 2026-06-17 publication 1.0 Operational altimetry processing traditionally relies on a “frozen sea” assumption, neglecting the influence of ocean dynamics on Doppler frequencies and introducing biases in estimated sea-state parameters. This dataset is based on an advanced SAR (Delay-Doppler) processing approach that overcomes this limitation by explicitly accounting for ocean surface dynamics. The methodology incorporates enhanced SAR models that jointly retrieve the standard deviation of vertical wave orbital velocities and the along-track component of the geophysical Doppler vector. These quantities are estimated through full two-dimensional retracking of unfocused SAR Delay-Doppler maps (stacks), rather than through the conventional summed Doppler beam approach used in operational processing. The processing has been implemented within the Sentinel Processing Prototype (SPP), leading to the generation of two six-month Sentinel-6A (S6A) data series covering January–June 2022 and January–June 2024. Validation results show that the dataset is fully consistent with conventional altimetry products in terms of sea surface height (SSH) and significant wave height (SWH), while providing reduced noise levels and improved along-track resolution. Key added-value parameters and improvements include: • Vertical wave velocity statistics: The dataset characterizes azimuth smearing induced by vertical wave motion, enabling the retrieval of the standard deviation of vertical wave velocity. This parameter is directly related to the mean zero up-crossing wave period and refines the estimation of sea-state conditions. Its inclusion reduces sea-state-dependent biases in SWH and shows strong agreement with ERA5 wave model outputs without requiring external corrections. • Geophysical Doppler contribution: The along-track component of the geophysical Doppler vector is estimated, providing information linked to wind direction and intensity, as well as surface currents (including contributions such as Stokes drift). Accounting for this term significantly reduces wind-dependent SSH biases, particularly between ascending and descending passes, while preserving large-scale spectral content. This dataset constitutes a demonstration product designed for the scientific community, showcasing the potential of advanced SAR retracking techniques. It delivers enhanced-resolution altimetry measurements together with improved SSH and SWH estimates, wave-period-related diagnostics derived from vertical velocity, and geophysical Doppler information. These features open new perspectives for coastal ocean applications, surface current studies, and swell characterization. CDS-AVISO CDS-AVISO CDS-AVISO AVISO aviso@altimetry.fr pointOfContact CDS-AVISO distributor CNES funder author CLS originator https://sextant.ifremer.fr/geonetwork/AVISO/api/records/05a92176-c60d-4579-8c14-a9cc01383fdd/attachments/S6_doppler_RTK_5_waves_period.png CDS-AVISO CDS-AVISO CDS-AVISO Centre de données ODATIS Centre de données ODATIS 2026-01-19 publication geonetwork.thesaurus.local.theme.odatis_centre_donnees Variables ODATIS Variables ODATIS 2023-10-13 publication geonetwork.thesaurus.local.theme.odatis_variables /Données d'observation/satellite /Données d'observation/satellite /Observational data/satellite Type de jeux de donnée ODATIS Type de jeux de donnée ODATIS 2025-12-09 publication geonetwork.thesaurus.local.theme.type_jeux_donnee Services Nationaux d'Observation Services Nationaux d'Observation 2025-12-09 publication geonetwork.thesaurus.local.theme.SNO Courants Courants Currents Vagues Vagues Waves ODATIS aggregation parameters and Essential Variable names ODATIS aggregation parameters and Essential Variable names 2025-07-29 publication geonetwork.thesaurus.external.theme.NVS.OD1 Courant marin Courant marin Ocean currents Vagues océaniques Vagues océaniques Ocean Waves Cersat - Parameter Cersat - Parameter 2025-12-09 publication geonetwork.thesaurus.local.theme.cersat_parameter Level 2 P Level 2 P Level 2 P Processing level Processing level 2025-12-09 publication geonetwork.thesaurus.local.processing-level.myocean.processing-level /Ocean Circulation /Ocean Circulation /Ocean Circulation /Ocean Waves /Ocean Waves /Ocean Waves Cersat - GCMD parameter Cersat - GCMD parameter 2024-01-04 publication geonetwork.thesaurus.external.theme.GCMDparameter Licence ouverte Licence ouverte Licence Ouverte Licence Ouverte Open Licence "The Sentinel-6 Delay-Doppler Altimetry Retracking 5 parameters product was produced by CNES and CLS and distributed by AVISO". CNES, & CLS. (2026). Sentinel-6 Delay-Doppler Altimetry Retracking 5 parameters product (Version 1.0) [Data set]. CNES. https://doi.org/10.24400/527896/AVISO-2026.008 " 350 utf8 oceans -180.00 180.00 -55.00 55.00 2022-01-01 2024-06-30 L2P NetCDF NetCDF https://tds-odatis.aviso.altimetry.fr/thredds/catalog/L4/dataset-duacs-dt-global-allsat-madt-fsle.html WWW:LINK Sentinel-6 Delay-Doppler Altimetry THREDDS THREDDS THREDDS https://www.aviso.altimetry.fr/fileadmin/documents/data/tools/hdbk_FSLE.pdf WWW:LINK User guide User guide Manuel Utilisateur Manuel Utilisateur Handbook WWW:LINK-1.0-http--publication-URL References Rodet L., et al., “Leveraging Delay-Doppler altimetry for Enhanced Sea-State Characterization.”, OSTST 2026 WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Amarouche, L. et al (2023). Analysis of waves dynamics impact on Sentinel-6MF delay/Doppler measurements. In Proceedings of the Ocean Surface Topography Science Team Meeting 2023, Puerto Rico, WV, USA, November 2023. WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Dinardo, S. et al. (2023). Sentinel-6 MF Poseidon-4 Radar Altimeter: Main Scientific Results from S6PP LRM and UF-SAR Chains in the First Year of the Mission.Advances in Space Research, 73(1), 337-375 WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Rodet, L. et al. (2024). Applying new processing capabilities in the SPP chain for improving wave characterization from Sentinel-3 and Sentinel-6MF mission data. 2024 30 Years of Progress in Radar Altimetry Symposium WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Buchhaupt, C. et al. (2021). Impact of vertical water particle motions on focused SAR altimetry.Advances in Space Research,68(2), 853-874 WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Buchhaupt, C. et al. (2023). Conditional sea surface statistics and their impact on geophysical sea surface parameters retrieved from SAR altimetry signals.Advances in Space Research,71(5), 2332-2347 WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Buchhaupt, C. et al. (2023). Towards the Mitigation of Discrepancies in Sea Surface Parameters estimated from Low- and High-Resolution Satellite Altimetry. Remote Sensing, 15, 4206 WWW:LINK-1.0-http--publication-URL Main publication link Main publication link Main publication link Marié, L. et al. (2024). On the Effects of Ocean Surface Motion on Delay-Doppler Altimetry. IEEE Transactions on Geoscience and Remote Sensing, 62, 1-25 https://doi.org/10.24400/527896/AVISO-2026.008 DOI Digital Object Identifier (DOI) Digital Object Identifier (DOI) Contents: multimission altimetry-derived gridded backward-in-time Finite Size Lyapunov Exponents and Orientations of associated eigenvectors. These products have been computed in collaboration between CLS, LOcean, CTOH and Cnes. Use: study of ocean variability in different domains of the biology (mesoscale and sub-mesoscale circulation, seasonal variation...), assimilation, .... Condition of access : These products are devoted to scientific applications and non-commercial useAccess Ssalto/Duacs products Data access services Description: gridded product, provided in delayed time. As a snapshot, each map represents the sea state for a given day. Spatial resolution: 1/25°x1/25° on a cartesian grid. Detailed description: a complete description is available as well as some examples of applications. Geographic coverage: global Contents: multimission altimetry-derived gridded backward-in-time Finite Size Lyapunov Exponents and Orientations of associated eigenvectors. These products have been computed in collaboration between CLS, LOcean, CTOH and Cnes. Use: study of ocean variability in different domains of the biology (mesoscale and sub-mesoscale circulation, seasonal variation...), assimilation, .... Condition of access : These products are devoted to scientific applications and non-commercial useAccess Ssalto/Duacs products Data access services Description: gridded product, provided in delayed time. As a snapshot, each map represents the sea state for a given day. Spatial resolution: 1/25°x1/25° on a cartesian grid. Detailed description: a complete description is available as well as some examples of applications. Geographic coverage: global V1.0 2026-06-10