Articles | Volume 21, issue 1
https://doi.org/10.5194/os-21-283-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-21-283-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
30 Jan 2025
Research article | Highlight paper |
| 30 Jan 2025
| 30 Jan 2025
Blending 2D topography images from the Surface Water and Ocean Topography (SWOT) mission into the altimeter constellation with the Level-3 multi-mission Data Unification and Altimeter Combination System (DUACS)
Gerald Dibarboure
CORRESPONDING AUTHOR
Centre National d'Etudes Spatiale (CNES), Toulouse, France
Cécile Anadon
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Frédéric Briol
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Emeline Cadier
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Robin Chevrier
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Antoine Delepoulle
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Yannice Faugère
Centre National d'Etudes Spatiale (CNES), Toulouse, France
Alice Laloue
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Rosemary Morrow
Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Toulouse, France
Nicolas Picot
Centre National d'Etudes Spatiale (CNES), Toulouse, France
Pierre Prandi
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Marie-Isabelle Pujol
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Matthias Raynal
Centre National d'Etudes Spatiale (CNES), Toulouse, France
Anaelle Tréboutte
Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France
Clément Ubelmann
Datlas, Grenoble, France
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Sea level observations along the swaths of the new SWOT (Surface Water and Ocean Topography) mission were used to characterize internal tides at three semidiurnal frequencies off the Amazon shelf in the tropical Atlantic during the SWOT calibration/validation period. The atlases were derived using harmonic analysis and principal component analysis. The SWOT-derived internal tide atlas outperforms the reference atlas previously used to correct SWOT observations.
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Maxime Ballarotta, Clément Ubelmann, Valentin Bellemin-Laponnaz, Florian Le Guillou, Guillaume Meda, Cécile Anadon, Alice Laloue, Antoine Delepoulle, Yannice Faugère, Marie-Isabelle Pujol, Ronan Fablet, and Gérald Dibarboure
Ocean Sci., 21, 63–80, https://doi.org/10.5194/os-21-63-2025, https://doi.org/10.5194/os-21-63-2025, 2025
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The Surface Water and Ocean Topography (SWOT) mission provides unprecedented swath altimetry data. This study examines SWOT's impact on mapping systems, showing a moderate effect with the current nadir altimetry constellation and a stronger impact with a reduced one. Integrating SWOT with dynamic mapping techniques improves the resolution of satellite-derived products, offering promising solutions for studying and monitoring sea-level variability at finer scales.
Michel Tchilibou, Simon Barbot, Loren Carrere, Ariane Koch-Larrouy, Gérald Dibarboure, and Clément Ubelmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-3947, https://doi.org/10.5194/egusphere-2024-3947, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
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This study presents the annual and monthly MIOST (MIOST24) internal tide atlases for the Indo-Philippine archipelago and the region off the Amazon shelf. Derived from 25 years of altimetry data and an updated wavelength database, the atlases reveal significant monthly variability of internal tides in both regions. The new atlas improves the correction of internal tides in altimetry data and outperforms MIOST 2022 and HRET existing atlases, thus supporting the development of a global atlas.
Antonio Sánchez-Román, Flora Gues, Romain Bourdalle-Badie, Marie-Isabelle Pujol, Ananda Pascual, and Marie Drévillon
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Karina von Schuckmann, Lorena Moreira, Mathilde Cancet, Flora Gues, Emmanuelle Autret, Ali Aydogdu, Lluis Castrillo, Daniele Ciani, Andrea Cipollone, Emanuela Clementi, Gianpiero Cossarini, Alvaro de Pascual-Collar, Vincenzo De Toma, Marion Gehlen, Rianne Giesen, Marie Drevillon, Claudia Fanelli, Kevin Hodges, Simon Jandt-Scheelke, Eric Jansen, Melanie Juza, Ioanna Karagali, Priidik Lagemaa, Vidar Lien, Leonardo Lima, Vladyslav Lyubartsev, Ilja Maljutenko, Simona Masina, Ronan McAdam, Pietro Miraglio, Helen Morrison, Tabea Rebekka Panteleit, Andrea Pisano, Marie-Isabelle Pujol, Urmas Raudsepp, Roshin Raj, Ad Stoffelen, Simon Van Gennip, Pierre Veillard, and Chunxue Yang
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Ocean Sci., 19, 1517–1527, https://doi.org/10.5194/os-19-1517-2023, https://doi.org/10.5194/os-19-1517-2023, 2023
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Elisa Carli, Rosemary Morrow, Oscar Vergara, Robin Chevrier, and Lionel Renault
Ocean Sci., 19, 1413–1435, https://doi.org/10.5194/os-19-1413-2023, https://doi.org/10.5194/os-19-1413-2023, 2023
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Antonio Sánchez-Román, M. Isabelle Pujol, Yannice Faugère, and Ananda Pascual
Ocean Sci., 19, 793–809, https://doi.org/10.5194/os-19-793-2023, https://doi.org/10.5194/os-19-793-2023, 2023
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This paper assesses the performance of the latest version (DT2021) of global gridded altimetry products distributed through the CMEMS and C3S Copernicus programs on the retrieval of sea level in the coastal zone of the European seas with respect to the previous DT2018 version. This comparison is made using an external independent dataset. DT2021 sea level products better solve the signal in the coastal band.
Adrien Guérou, Benoit Meyssignac, Pierre Prandi, Michaël Ablain, Aurélien Ribes, and François Bignalet-Cazalet
Ocean Sci., 19, 431–451, https://doi.org/10.5194/os-19-431-2023, https://doi.org/10.5194/os-19-431-2023, 2023
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Based on the latest satellite observations published by the French space agency CNES, we present the current state of the sea level at the scale of the planet and assess its rise and acceleration over the past 29 years. To support scientific research we provide updated estimations of our confidence in our estimations and highlight key technological and scientific fields. Making progress on that will help to better characterize the sea level in the future.
Oscar Vergara, Rosemary Morrow, Marie-Isabelle Pujol, Gérald Dibarboure, and Clément Ubelmann
Ocean Sci., 19, 363–379, https://doi.org/10.5194/os-19-363-2023, https://doi.org/10.5194/os-19-363-2023, 2023
Short summary
Short summary
Recent advances allow us to observe the ocean from space with increasingly higher detail, challenging our knowledge of the ocean's surface height signature. We use a statistical approach to determine the spatial scale at which the sea surface height signal is no longer dominated by geostrophic turbulence but in turn becomes dominated by wave-type motions. This information helps us to better use the data provided by ocean-observing satellites and to gain knowledge on climate-driving processes.
Maxime Ballarotta, Clément Ubelmann, Pierre Veillard, Pierre Prandi, Hélène Etienne, Sandrine Mulet, Yannice Faugère, Gérald Dibarboure, Rosemary Morrow, and Nicolas Picot
Earth Syst. Sci. Data, 15, 295–315, https://doi.org/10.5194/essd-15-295-2023, https://doi.org/10.5194/essd-15-295-2023, 2023
Short summary
Short summary
We present a new gridded sea surface height and current dataset produced by combining observations from nadir altimeters and drifting buoys. This product is based on a multiscale and multivariate mapping approach that offers the possibility to improve the physical content of gridded products by combining the data from various platforms and resolving a broader spectrum of ocean surface dynamic than in the current operational mapping system. A quality assessment of this new product is presented.
Michel Tchilibou, Ariane Koch-Larrouy, Simon Barbot, Florent Lyard, Yves Morel, Julien Jouanno, and Rosemary Morrow
Ocean Sci., 18, 1591–1618, https://doi.org/10.5194/os-18-1591-2022, https://doi.org/10.5194/os-18-1591-2022, 2022
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This high-resolution model-based study investigates the variability in the generation, propagation, and sea height signature (SSH) of the internal tide off the Amazon shelf during two contrasted seasons. ITs propagate further north during the season characterized by weak currents and mesoscale eddies and a shallow and strong pycnocline. IT imprints on SSH dominate those of the geostrophic motion for horizontal scales below 200 km; moreover, the SSH is mainly incoherent below 70 km.
Marie-Isabelle Pujol, Stéphanie Dupuy, Oscar Vergara, Antonio Sánchez-Román, Yannice Faugère, Pierre Prandi, Mei-Ling Dabat, Quentin Dagneaux, Marine Lievin, Emeline Cadier, Gérald Dibarboure, and Nicolas Picot
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2022-292, https://doi.org/10.5194/essd-2022-292, 2022
Manuscript not accepted for further review
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An altimeter sea level along-track level-3 product with a 5 Hz (~1.2 km) sampling is proposed. It takes advantage of recent advances in radar altimeter processing, and improvements made to different stages of the processing chain. Compared to the conventional 1 Hz (~7 km) product, it significantly improves the observability of the short wavelength signal in open ocean and near coast areas (> 5 km). It also contributes to improving high resolution numerical model outputs via data assimilation.
Mounir Benkiran, Pierre-Yves Le Traon, and Gérald Dibarboure
Ocean Sci., 18, 609–625, https://doi.org/10.5194/os-18-609-2022, https://doi.org/10.5194/os-18-609-2022, 2022
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The SSH analysis and 7 d forecast error will be globally reduced by almost 50 %. Surface current forecast errors should be equivalent to today’s surface current analysis errors or alternatively will be improved (variance error reduction) by 30 % at the surface and 50 % for 300 m depth.
The resolution capabilities will be drastically improved and will be closer to 100 km wavelength as opposed to today where they are above 250 km (on average).
Clément Ubelmann, Loren Carrere, Chloé Durand, Gérald Dibarboure, Yannice Faugère, Maxime Ballarotta, Frédéric Briol, and Florent Lyard
Ocean Sci., 18, 469–481, https://doi.org/10.5194/os-18-469-2022, https://doi.org/10.5194/os-18-469-2022, 2022
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The signature of internal tides has become an important component for high-resolution altimetry over oceans. Several studies have proposed some solutions to resolve part of these internal tides based on the altimetry record. Following these studies, we propose here a new inversion approach aimed to mitigate aliasing with other dynamics. After a description of the methodology, the solution for the main tidal components has been successfully validated against independent observations.
Cori Pegliasco, Antoine Delepoulle, Evan Mason, Rosemary Morrow, Yannice Faugère, and Gérald Dibarboure
Earth Syst. Sci. Data, 14, 1087–1107, https://doi.org/10.5194/essd-14-1087-2022, https://doi.org/10.5194/essd-14-1087-2022, 2022
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The new global Mesoscale Eddy Trajectory Atlases (META3.1exp) provide eddy identification and trajectories from altimetry maps. These atlases comprise an improvement to and continuation of the historical META2.0 product. Changes in the detection parameters and tracking were tested by comparing the eddies from the different datasets. In particular, the eddy contours available in META3.1exp are an asset for multi-disciplinary studies.
Pierre Prandi, Jean-Christophe Poisson, Yannice Faugère, Amandine Guillot, and Gérald Dibarboure
Earth Syst. Sci. Data, 13, 5469–5482, https://doi.org/10.5194/essd-13-5469-2021, https://doi.org/10.5194/essd-13-5469-2021, 2021
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We investigate how mapping sea level in the Arctic Ocean can benefit from combining data from three satellite radar altimeters: CryoSat-2, Sentinel-3A and SARAL/AltiKa. A dedicated processing for SARAL/AltiKa provides a baseline for the cross-referencing of CryoSat-2 and Sentinel-3A before mapping. We show that by combining measurements coming from three missions, we are able to increase the resolution of gridded sea level fields in the ice-covered Arctic Ocean.
Jean-Michel Zigna, Reda Semlal, Flavien Gouillon, Ethan Davis, Elisabeth Lambert, Frédéric Briol, Romain Prod-Homme, Sean Arms, and Lionel Zawadzki
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2021-138, https://doi.org/10.5194/gmd-2021-138, 2021
Preprint withdrawn
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The Parquet Cube storage alternative presented here is compared with Pangeo and THREDDS platforms to access to gridded data for large scale processing and modeling. Stressing the 3 implementations through 3 data scientists' scenarii, this Parquet Cube Alternative appears to be a good candidate to share gridded data in a cloud environment and share them through different communities of users. This open source alternative can be enriched by additional services to subset, enrich or explore data.
Sandrine Mulet, Marie-Hélène Rio, Hélène Etienne, Camilia Artana, Mathilde Cancet, Gérald Dibarboure, Hui Feng, Romain Husson, Nicolas Picot, Christine Provost, and P. Ted Strub
Ocean Sci., 17, 789–808, https://doi.org/10.5194/os-17-789-2021, https://doi.org/10.5194/os-17-789-2021, 2021
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Satellite altimetry has revolutionized ocean observation by allowing the sea level to be monitored with very good spatiotemporal coverage. However, only the sea level anomalies are retrieved; to monitor the whole oceanic signal a temporal mean (called mean dynamic topography, MDT) must be added to these anomalies. In this study we present the newly updated CNES-CLS18 MDT. An evaluation of this new solution shows significant improvements in both strong currents and coastal areas.
Florent H. Lyard, Damien J. Allain, Mathilde Cancet, Loren Carrère, and Nicolas Picot
Ocean Sci., 17, 615–649, https://doi.org/10.5194/os-17-615-2021, https://doi.org/10.5194/os-17-615-2021, 2021
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Since the mid-1990s, a series of FES (finite element solution) global ocean tidal atlases has been produced with the primary objective to provide altimetry missions with a tidal de-aliasing correction. We describe the underlying hydrodynamic/data assimilation design and accuracy assessments for the FES2014 release. The FES2014 atlas shows overall improved performance and has consequently been integrated in satellite altimetry and gravimetric data processing and adopted in ITRF standards.
Loren Carrere, Brian K. Arbic, Brian Dushaw, Gary Egbert, Svetlana Erofeeva, Florent Lyard, Richard D. Ray, Clément Ubelmann, Edward Zaron, Zhongxiang Zhao, Jay F. Shriver, Maarten Cornelis Buijsman, and Nicolas Picot
Ocean Sci., 17, 147–180, https://doi.org/10.5194/os-17-147-2021, https://doi.org/10.5194/os-17-147-2021, 2021
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Internal tides can have a signature of several centimeters at the ocean surface and need to be corrected from altimeter measurements. We present a detailed validation of several internal-tide models using existing satellite altimeter databases. The analysis focuses on the main diurnal and semidiurnal tidal constituents. Results show the interest of the methodology proposed, the quality of the internal-tide models tested and their positive contribution for estimating an accurate sea level.
Guillaume Sérazin, Frédéric Marin, Lionel Gourdeau, Sophie Cravatte, Rosemary Morrow, and Mei-Ling Dabat
Ocean Sci., 16, 907–925, https://doi.org/10.5194/os-16-907-2020, https://doi.org/10.5194/os-16-907-2020, 2020
Michel Tchilibou, Lionel Gourdeau, Florent Lyard, Rosemary Morrow, Ariane Koch Larrouy, Damien Allain, and Bughsin Djath
Ocean Sci., 16, 615–635, https://doi.org/10.5194/os-16-615-2020, https://doi.org/10.5194/os-16-615-2020, 2020
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This paper focuses on internal tides in the marginal Solomon Sea where LLWBCs transit. The objective is to characterize such internal tides and to give some insights into their impacts on water mass transformation in this area of interest for the global circulation. Results are discussed for two contrasted ENSO conditions with different mesoscale activity and stratification. Such study is motivated by the next altimetric SWOT mission that will be able to observe such phenomena.
Guillaume Taburet, Antonio Sanchez-Roman, Maxime Ballarotta, Marie-Isabelle Pujol, Jean-François Legeais, Florent Fournier, Yannice Faugere, and Gerald Dibarboure
Ocean Sci., 15, 1207–1224, https://doi.org/10.5194/os-15-1207-2019, https://doi.org/10.5194/os-15-1207-2019, 2019
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This paper deals with sea level altimetery products. These geophysical data are distributed as along-track and gridded data through Copernicus programs CMEMS and C3S. We present in detail a new reprocessing of the data (DT2018) from 1993 to 2017. The main changes and their impacts since the last version (DT2014) are carefully discussed. This comparison is made using an independent dataset. DT2018 sea level products are improved at the global and regional scale, especially in coastal areas.
Maxime Ballarotta, Clément Ubelmann, Marie-Isabelle Pujol, Guillaume Taburet, Florent Fournier, Jean-François Legeais, Yannice Faugère, Antoine Delepoulle, Dudley Chelton, Gérald Dibarboure, and Nicolas Picot
Ocean Sci., 15, 1091–1109, https://doi.org/10.5194/os-15-1091-2019, https://doi.org/10.5194/os-15-1091-2019, 2019
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This study investigates the resolving capabilities of the DUACS gridded products delivered through the CMEMS catalogue. Our method is based on the noise-to-signal ratio approach. While altimeter along-track data resolve scales on the order of a few tens of kilometers, we found that the merging of these along-track data into continuous maps in time and space leads to effective resolution ranging from ~ 800 km wavelength at the Equator to 100 km wavelength at high latitude.
Michaël Ablain, Benoît Meyssignac, Lionel Zawadzki, Rémi Jugier, Aurélien Ribes, Giorgio Spada, Jerôme Benveniste, Anny Cazenave, and Nicolas Picot
Earth Syst. Sci. Data, 11, 1189–1202, https://doi.org/10.5194/essd-11-1189-2019, https://doi.org/10.5194/essd-11-1189-2019, 2019
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A description of the uncertainties in the Global Mean Sea Level (GMSL) record has been performed; 25 years of satellite altimetry data were used to estimate the error variance–covariance matrix for the GMSL record to derive its confidence envelope. Then a least square approach was used to estimate the GMSL trend and acceleration uncertainties over any time periods. A GMSL trend of 3.35 ± 0.4 mm/yr and a GMSL acceleration of 0.12 ± 0.07 mm/yr² have been found within a 90 % confidence level.
Michel Tchilibou, Lionel Gourdeau, Rosemary Morrow, Guillaume Serazin, Bughsin Djath, and Florent Lyard
Ocean Sci., 14, 1283–1301, https://doi.org/10.5194/os-14-1283-2018, https://doi.org/10.5194/os-14-1283-2018, 2018
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This paper is motivated by the next SWOT altimetric mission dedicated to the observation of mesoscale and submesoscale oceanic features. It focuses on tropical areas with a strong discrepancy in the spectral signature between altimetry and models. The paper reviews the spectral signature of tropical turbulence which presents a rich variety of phenomena depending on the latitudinal dependence of the Coriolis force. Internal tides observed by altimetry explain the discrepancy with the model.
Fabrice Ardhuin, Yevgueny Aksenov, Alvise Benetazzo, Laurent Bertino, Peter Brandt, Eric Caubet, Bertrand Chapron, Fabrice Collard, Sophie Cravatte, Jean-Marc Delouis, Frederic Dias, Gérald Dibarboure, Lucile Gaultier, Johnny Johannessen, Anton Korosov, Georgy Manucharyan, Dimitris Menemenlis, Melisa Menendez, Goulven Monnier, Alexis Mouche, Frédéric Nouguier, George Nurser, Pierre Rampal, Ad Reniers, Ernesto Rodriguez, Justin Stopa, Céline Tison, Clément Ubelmann, Erik van Sebille, and Jiping Xie
Ocean Sci., 14, 337–354, https://doi.org/10.5194/os-14-337-2018, https://doi.org/10.5194/os-14-337-2018, 2018
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The Sea surface KInematics Multiscale (SKIM) monitoring mission is a proposal for a future satellite that is designed to measure ocean currents and waves. Using a Doppler radar, the accurate measurement of currents requires the removal of the mean velocity due to ocean wave motions. This paper describes the main processing steps needed to produce currents and wave data from the radar measurements. With this technique, SKIM can provide unprecedented coverage and resolution, over the global ocean.
Rosemary Morrow, Alice Carret, Florence Birol, Fernando Nino, Guillaume Valladeau, Francois Boy, Celine Bachelier, and Bruno Zakardjian
Ocean Sci., 13, 13–29, https://doi.org/10.5194/os-13-13-2017, https://doi.org/10.5194/os-13-13-2017, 2017
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Spectral analyses of along-track altimetric data are used to estimate noise levels and observable ocean scales in the NW Mediterranean Sea. In winter, all altimetric missions can observe wavelengths down to 40–50 km (individual feature diameters of 20–25 km). In summer, SARAL can detect scales down to 35 km, whereas Jason-2 and CryoSat-2 with higher noise can only observe scales less than 50–55 km. Along-track altimeter data are also compared with collocated glider and coastal HF radar data.
Marie-Isabelle Pujol, Yannice Faugère, Guillaume Taburet, Stéphanie Dupuy, Camille Pelloquin, Michael Ablain, and Nicolas Picot
Ocean Sci., 12, 1067–1090, https://doi.org/10.5194/os-12-1067-2016, https://doi.org/10.5194/os-12-1067-2016, 2016
Lionel Zawadzki, Michaël Ablain, Loren Carrere, Richard D. Ray, Nikita P. Zelensky, Florent Lyard, Amandine Guillot, and Nicolas Picot
Ocean Sci. Discuss., https://doi.org/10.5194/os-2016-19, https://doi.org/10.5194/os-2016-19, 2016
Preprint withdrawn
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Mean sea level (MSL) is a prominent indicator of climatic change, and is therefore of great scientific and societal interest. Since the beginning of the altimeter mission TOPEX/Poseidon and its successors Jason-1 and Jason-2, MSL products became essential for climate applications. Since 1995, a suspicious signal is apparent in the corresponding MSL record. Since 2010, scientific teams have been working on reducing this error. This paper assesses, characterizes and quantifies this reduction.
Jean-François Legeais, Pierre Prandi, and Stéphanie Guinehut
Ocean Sci., 12, 647–662, https://doi.org/10.5194/os-12-647-2016, https://doi.org/10.5194/os-12-647-2016, 2016
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Sea level is a key indicator of climate change and has been monitored by satellite altimetry for more than 2 decades. The evaluation of the performances of the altimeter missions can be performed by comparison with in situ-independent measurements from Argo profiling floats. This allows for the detection of altimeter drift and the estimation of the impact of a new altimeter standard. This study aims at characterizing the errors of the method thanks to sensitivity analyses to different parameters.
F. d'Ovidio, A. Della Penna, T. W. Trull, F. Nencioli, M.-I. Pujol, M.-H. Rio, Y.-H. Park, C. Cotté, M. Zhou, and S. Blain
Biogeosciences, 12, 5567–5581, https://doi.org/10.5194/bg-12-5567-2015, https://doi.org/10.5194/bg-12-5567-2015, 2015
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Field campaigns are instrumental in providing ground truth for understanding and modeling global ocean biogeochemical budgets. A survey however can only inspect a fraction of the global oceans, typically a region hundreds of kilometers wide for a temporal window of the order of (at most) several weeks. In this spatiotemporal domain, mesoscale variability can mask climatological contrasts. Here we propose the use of multisatellite-based Lagrangian diagnostics to solve this issue.
M. Ablain, A. Cazenave, G. Larnicol, M. Balmaseda, P. Cipollini, Y. Faugère, M. J. Fernandes, O. Henry, J. A. Johannessen, P. Knudsen, O. Andersen, J. Legeais, B. Meyssignac, N. Picot, M. Roca, S. Rudenko, M. G. Scharffenberg, D. Stammer, G. Timms, and J. Benveniste
Ocean Sci., 11, 67–82, https://doi.org/10.5194/os-11-67-2015, https://doi.org/10.5194/os-11-67-2015, 2015
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This paper presents various respective data improvements achieved within the European Space Agency (ESA) Climate Change Initiative (ESA CCI) project on sea level during its first phase (2010-2013), using multi-mission satellite altimetry data over the 1993-2010 time span.
S. T. Gille, M. M. Carranza, R. Cambra, and R. Morrow
Biogeosciences, 11, 6389–6400, https://doi.org/10.5194/bg-11-6389-2014, https://doi.org/10.5194/bg-11-6389-2014, 2014
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The Kerguelen Plateau supports a strong spring chlorophyll bloom, in contrast with most of the Southern Ocean. Throughout the Southern Ocean, including in the Kerguelen area, wind can determine oceanic vertical velocities that may bring nutrients to the surface and contribute to the development of blooms. The Kerguelen Island itself generates a wind shadow that locally enhances upwelling velocities to the north of the main axis of the winds, and chlorophyll is high in this upwelling region.
Related subject area
Approach: Remote Sensing | Properties and processes: Mesoscale to submesoscale dynamics
Estimating ocean currents from the joint reconstruction of absolute dynamic topography and sea surface temperature through deep learning algorithms
Integrating wide-swath altimetry data into Level-4 multi-mission maps
Monitoring the coastal–offshore water interactions in the Levantine Sea using ocean color and deep supervised learning
Multiple timescale variations in fronts in the Seto Inland Sea, Japan
MAESSTRO: Masked Autoencoders for Sea Surface Temperature Reconstruction under Occlusion
Deep learning for the super resolution of Mediterranean sea surface temperature fields
Generation of super-resolution gap-free ocean colour satellite products using DINEOF
Impact of surface and subsurface-intensified eddies on sea surface temperature and chlorophyll a in the northern Indian Ocean utilizing deep learning
Regional mapping of energetic short mesoscale ocean dynamics from altimetry: performances from real observations
Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT
Daniele Ciani, Claudia Fanelli, and Bruno Buongiorno Nardelli
Ocean Sci., 21, 199–216, https://doi.org/10.5194/os-21-199-2025, https://doi.org/10.5194/os-21-199-2025, 2025
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Ocean surface currents are routinely derived from satellite observations of the sea level, allowing regional- to global-scale synoptic monitoring. In order to overcome the theoretical and instrumental limits of this methodology, we exploit the synergy of multi-sensor satellite observations. We rely on deep learning, physics-informed algorithms to predict ocean currents from sea surface height and sea surface temperature observations. Results are validated by means of in situ measurements.
Maxime Ballarotta, Clément Ubelmann, Valentin Bellemin-Laponnaz, Florian Le Guillou, Guillaume Meda, Cécile Anadon, Alice Laloue, Antoine Delepoulle, Yannice Faugère, Marie-Isabelle Pujol, Ronan Fablet, and Gérald Dibarboure
Ocean Sci., 21, 63–80, https://doi.org/10.5194/os-21-63-2025, https://doi.org/10.5194/os-21-63-2025, 2025
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The Surface Water and Ocean Topography (SWOT) mission provides unprecedented swath altimetry data. This study examines SWOT's impact on mapping systems, showing a moderate effect with the current nadir altimetry constellation and a stronger impact with a reduced one. Integrating SWOT with dynamic mapping techniques improves the resolution of satellite-derived products, offering promising solutions for studying and monitoring sea-level variability at finer scales.
Georges Baaklini, Julien Brajard, Leila Issa, Gina Fifani, Laurent Mortier, and Roy El Hourany
Ocean Sci., 20, 1707–1720, https://doi.org/10.5194/os-20-1707-2024, https://doi.org/10.5194/os-20-1707-2024, 2024
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Understanding the flow of the Levantine Sea surface current is not straightforward. We propose a study based on learning techniques to follow interactions between water near the shore and further out at sea. Our results show changes in the coastal currents past 33.8° E, with frequent instances of water breaking away along the Lebanese coast. These events happen quickly and sometimes lead to long-lasting eddies. This study underscores the need for direct observations to improve our knowledge.
Menghong Dong and Xinyu Guo
Ocean Sci., 20, 1527–1546, https://doi.org/10.5194/os-20-1527-2024, https://doi.org/10.5194/os-20-1527-2024, 2024
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We employed a gradient-based algorithm to identify the position and intensity of the fronts in a coastal sea using sea surface temperature data, thereby quantifying their variations. Our study provides a comprehensive analysis of these fronts, elucidating their seasonal variability, intra-tidal dynamics, and the influence of winds on the fronts. By capturing the temporal and spatial dynamics of these fronts, our understanding of the complex oceanographic processes within this region is enhanced.
Edwin Goh, Alice Yepremyan, Jinbo Wang, and Brian Wilson
Ocean Sci., 20, 1309–1323, https://doi.org/10.5194/os-20-1309-2024, https://doi.org/10.5194/os-20-1309-2024, 2024
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An AI model was used to fill in missing parts of sea temperature (SST) maps caused by cloud cover. We found masked autoencoders can recreate missing SSTs with less than 0.2 °C error, even when 80 % are missing. This is 5000 times faster than conventional methods tested on a single central processing unit. This can enhance our ability in monitoring global small-scale ocean fronts that affect heat, carbon, and nutrient exchange in the ocean. The method is promising for future research.
Claudia Fanelli, Daniele Ciani, Andrea Pisano, and Bruno Buongiorno Nardelli
Ocean Sci., 20, 1035–1050, https://doi.org/10.5194/os-20-1035-2024, https://doi.org/10.5194/os-20-1035-2024, 2024
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Sea surface temperature (SST) is an essential variable to understanding the Earth's climate system, and its accurate monitoring from space is essential. Since satellite measurements are hindered by cloudy/rainy conditions, data gaps are present even in merged multi-sensor products. Since optimal interpolation techniques tend to smooth out small-scale features, we developed a deep learning model to enhance the effective resolution of gap-free SST images over the Mediterranean Sea to address this.
Aida Alvera-Azcárate, Dimitry Van der Zande, Alexander Barth, Antoine Dille, Joppe Massant, and Jean-Marie Beckers
EGUsphere, https://doi.org/10.5194/egusphere-2024-1268, https://doi.org/10.5194/egusphere-2024-1268, 2024
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This work presents an approach to increase the spatial resolution of satellite data and interpolate gaps dur to cloud cover, using a method called DINEOF (Data Interpolating Empirical Orthogonal Functions). The method is tested on turbidity and chlorophyll-a concentration data in the Belgian coastal zone and the North Sea. The results show that we are able to improve the spatial resolution of these data in order to perform analysis of spatial and temporal variability in the coastal regions.
Yingjie Liu and Xiaofeng Li
Ocean Sci., 19, 1579–1593, https://doi.org/10.5194/os-19-1579-2023, https://doi.org/10.5194/os-19-1579-2023, 2023
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The study developed a deep learning model that effectively distinguishes between surface- and subsurface-intensified eddies in the northern Indian Ocean by integrating sea surface height and temperature data. The accurate distinction between these types of eddies provides valuable insights into their dynamics and their impact on marine ecosystems in the northern Indian Ocean and contributes to understanding the complex interactions between eddy dynamics and biogeochemical processes in the ocean.
Florian Le Guillou, Lucile Gaultier, Maxime Ballarotta, Sammy Metref, Clément Ubelmann, Emmanuel Cosme, and Marie-Helène Rio
Ocean Sci., 19, 1517–1527, https://doi.org/10.5194/os-19-1517-2023, https://doi.org/10.5194/os-19-1517-2023, 2023
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Altimetry provides sea surface height (SSH) data along one-dimensional tracks. For many applications, the tracks are interpolated in space and time to provide gridded SSH maps. The operational SSH gridded products filter out the small-scale signals measured on the tracks. This paper evaluates the performances of a recently implemented dynamical method to retrieve the small-scale signals from real SSH data. We show a net improvement in the quality of SSH maps when compared to independent data.
Elisa Carli, Rosemary Morrow, Oscar Vergara, Robin Chevrier, and Lionel Renault
Ocean Sci., 19, 1413–1435, https://doi.org/10.5194/os-19-1413-2023, https://doi.org/10.5194/os-19-1413-2023, 2023
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Oceanic eddies are the structures carrying most of the energy in our oceans. They are key to climate regulation and nutrient transport. We prepare for the Surface Water and Ocean Topography mission, studying eddy dynamics in the region south of Africa, where the Indian and Atlantic oceans meet, using models and simulated satellite data. SWOT will provide insights into the structures smaller than what is currently observable, which appear to greatly contribute to eddy kinetic energy and strain.
Cited articles
Ajayi, A., Le Sommer, J., Chassignet, E., Molines, J.-M., Xu, X., Albert, A., and Cosme, E.: Spatial and Temporal Variability of the North Atlantic Eddy Field From Two Kilometric-Resolution Ocean Models, J. Geophys. Res.-Oceans, 125, e2019JC015827, https://doi.org/10.1029/2019JC015827, 2020.
Arbic, B. K., Scott, R. B., Chelton, D. B., Richman, J. G., and Shriver, J. F.: Effects of stencil width on surface ocean geostrophic velocity and vorticity estimation from gridded satellite altimeter data, J. Geophys. Res.-Oceans, 117, C03029, https://doi.org/10.1029/2011JC007367, 2012.
AVISO/DUACS: SWOT Level-3 KaRIn Low Rate SSH Basic (v1.0.2), CNES [data set], https://doi.org/10.24400/527896/A01-2023.017, 2024a.
AVISO/DUACS: SWOT Level-3 KaRIn Low Rate SSH Expert (v1.0.2), CNES [data set], https://doi.org/10.24400/527896/A01-2023.018, 2024b.
AVISO/DUACS: SWOT Level-3 KaRIn Low Rate SSH Unsmoothed (v1.0.2), CNES [data set], https://doi.org/10.24400/527896/A01-2024.003, 2024c.
Ballarotta, M., Ubelmann, C., Pujol, M.-I., Taburet, G., Fournier, F., Legeais, J.-F., Faugère, Y., Delepoulle, A., Chelton, D., Dibarboure, G., and Picot, N.: On the resolutions of ocean altimetry maps, Ocean Sci., 15, 1091–1109, https://doi.org/10.5194/os-15-1091-2019, 2019.
Bohé, A.: KaRIn LR Oceanography Products Status & Examples, in: 2023 SWOT Science Team meeting, Toulouse, France, 2023, https://swotst.aviso.altimetry.fr/fileadmin/user_upload/SWOTST2023/20230919_2_Karin_overview1/11h30-BOHE_plenary.pdf (last access: 12 March 2024), 2023.
Brodeau, L., Sommer, J. L., and Albert, A.: ocean-next/eNATL60: Material describing the set-up and the assessment of NEMO-eNATL60 simulations, Zenodo [data set], https://doi.org/10.5281/zenodo.4032732, 2020.
Carrère, L., Lyard, F., Cancet, M., Allain, D., Fouchet, E., Dabat, M., Tchilibou, M., Ferrari, R., and Faugere, Y.: The new FES2022 Tidal atlas, in: 2023 SWOT Science Team meeting, Toulouse, France, 2023, https://doi.org/10.24400/527896/a03-2022.3287, 2023.
CEOS: The Next 15 Years of Satellite Altimetry Ocean Surface Topography Constellation: User Requirements Document, https://ceos.org/observations/documents/Satellite_Altimetry_Report_2009-10.pdf (last access: 12 March 2024), 2009.
Chelton, D. B., Samelson, R. M., and Farrar, J. T.: The effects of uncorrelated measurement noise on SWOT estimates of Sea surface height, velocity, and vorticity, J. Atmos. Ocean. Tech., 39, 1053–1083, 2022.
Chen, C.: Features of KaRIn Data that Users Should be Aware of, in: 2023 SWOT Science Team meeting, Toulouse, France, 2023, https://swotst.aviso.altimetry.fr/fileadmin/user_upload/SWOTST2023/20230919_3_Karin_overview2/14h10-KaRInFeatures.pdf (last access: 12 March 2024), 2023.
Davidson, F., Alvera-Azcarate, A., Barth, A., Brassington, G. B., Chassignet, E. P., Clementi, E., and Zu, Z.: Synergies in operational oceanography: the intrinsic need for sustained ocean observations, Front. Mar. Sci., 6, 450, https://doi.org/10.3389/fmars.2019.00450, 2019.
Dibarboure, G. and Morrow, R.: Value of the Jason-1 geodetic phase to study rapid oceanic changes and importance for defining a Jason-2 geodetic orbit, J. Atmos. Ocean. Tech., 33, 1913–1930, 2016.
Dibarboure, G. and Pujol, M. I.: Improving the quality of Sentinel-3A data with a hybrid mean sea surface model, and implications for Sentinel-3B and SWOT, Adv. Space Res., 68, 1116–1139, 2021.
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Co-editor-in-chief
This paper thoroughly describes the data processing steps and assessment of the usefulness of the new SWOT mission for advancing ocean science. The paper will be of great interest the ocean and sea ice communities and others. The discussion of the benefits, relevance, and limitations of Level-3 swath-altimeter products for various research domains is particularly important.
This paper thoroughly describes the data processing steps and assessment of the usefulness of...
Short summary
The Surface Water and Ocean Topography (SWOT) mission delivers unprecedented swath-altimetry products. In this paper, we describe how we extended the Level-3 algorithms to handle SWOT’s unique swath-altimeter data. We also illustrate and discuss the benefits, relevance, and limitations of Level-3 swath-altimeter products for various research domains.
The Surface Water and Ocean Topography (SWOT) mission delivers unprecedented swath-altimetry...
