Articles | Volume 15, issue 4
https://doi.org/10.5194/os-15-1091-2019
© Author(s) 2019. 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-15-1091-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
20 Aug 2019
Research article |
| 20 Aug 2019
| 20 Aug 2019
On the resolutions of ocean altimetry maps
Maxime Ballarotta
CORRESPONDING AUTHOR
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Clément Ubelmann
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Marie-Isabelle Pujol
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Guillaume Taburet
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Florent Fournier
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Jean-François Legeais
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Yannice Faugère
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Antoine Delepoulle
Collecte Localisation Satellites, 31520 Ramonville-Saint-Agne, France
Dudley Chelton
College of Earth, Ocean and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Gérald Dibarboure
Centre National d'Études Spatiales, 31400 Toulouse, France
Nicolas Picot
Centre National d'Études Spatiales, 31400 Toulouse, France
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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.
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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.
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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.
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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.
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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.
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Revised manuscript not accepted
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Antonio Sánchez-Román, Flora Gues, Romain Bourdalle-Badie, Marie-Isabelle Pujol, Ananda Pascual, and Marie Drévillon
State Planet, 4-osr8, 4, https://doi.org/10.5194/sp-4-osr8-4-2024, https://doi.org/10.5194/sp-4-osr8-4-2024, 2024
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This study investigates the changing pattern of the Gulf Stream over the last 3 decades as observed in the altimetric record (1993–2022). Changes in the Gulf Stream path have an effect on its speed (and associated energy) and also on waters transported towards the subpolar North Atlantic, impacting Europe's climate. The observed shifts in the paths seem to be linked to variability in the North Atlantic Ocean during winter that may play an important role.
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Satellite altimetry shows that daily mean significant wave heights (SWHs) and extreme SWHs have increased in the Southern Ocean, the South Atlantic, and the southern Indian Ocean over the last 2 decades. In winter in the North Atlantic, SWH has increased north of 45°N and decreased south of 45°N. SWHs likely to be exceeded every 100 years have also increased in the North Atlantic and the eastern tropical Pacific. However, this study also revealed the need for longer and more consistent series.
Karina von Schuckmann, Lorena Moreira, Mathilde Cancet, Flora Gues, Emmanuelle Autret, Jonathan Baker, Clément Bricaud, Romain Bourdalle-Badie, Lluis Castrillo, Lijing Cheng, Frederic Chevallier, Daniele Ciani, Alvaro de Pascual-Collar, Vincenzo De Toma, Marie Drevillon, Claudia Fanelli, Gilles Garric, Marion Gehlen, Rianne Giesen, Kevin Hodges, Doroteaciro Iovino, Simon Jandt-Scheelke, Eric Jansen, Melanie Juza, Ioanna Karagali, Thomas Lavergne, Simona Masina, Ronan McAdam, Audrey Minière, Helen Morrison, Tabea Rebekka Panteleit, Andrea Pisano, Marie-Isabelle Pujol, Ad Stoffelen, Sulian Thual, Simon Van Gennip, Pierre Veillard, Chunxue Yang, and Hao Zuo
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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.
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
Short summary
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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.
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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.
Oscar Vergara, Rosemary Morrow, Marie-Isabelle Pujol, Gérald Dibarboure, and Clément Ubelmann
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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.
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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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.
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.
Yvan Gouzenes, Fabien Léger, Anny Cazenave, Florence Birol, Pascal Bonnefond, Marcello Passaro, Fernando Nino, Rafael Almar, Olivier Laurain, Christian Schwatke, Jean-François Legeais, and Jérôme Benveniste
Ocean Sci., 16, 1165–1182, https://doi.org/10.5194/os-16-1165-2020, https://doi.org/10.5194/os-16-1165-2020, 2020
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This study provides for the first time estimates of sea level anomalies very close to the coastline based on high-resolution retracked altimetry data, as well as corresponding sea level trends, over a 14-year time span. This new information has so far not been provided by standard altimetry data.
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.
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.
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.
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.
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. Ballarotta, F. Roquet, S. Falahat, Q. Zhang, and G. Madec
Clim. Past Discuss., https://doi.org/10.5194/cpd-11-3597-2015, https://doi.org/10.5194/cpd-11-3597-2015, 2015
Revised manuscript not accepted
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We investigate the impact of the ocean geothermal heating (OGH) on a glacial ocean state using numerical simulations. We found that the OGH is a significant forcing of the abyssal ocean and thermohaline circulation. Applying the OGH warms the Antarctic Bottom Water by ~0.4°C and strengthens the deep circulation by 15% to 30%. The geothermally heated waters are advected from the Indo-Pacific to the North Atlantic basin, indirectly favouring the deep convection in the North Atlantic.
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.
M. Ballarotta, S. Falahat, L. Brodeau, and K. Döös
Ocean Sci., 10, 907–921, https://doi.org/10.5194/os-10-907-2014, https://doi.org/10.5194/os-10-907-2014, 2014
M. Ballarotta, L. Brodeau, J. Brandefelt, P. Lundberg, and K. Döös
Clim. Past, 9, 2669–2686, https://doi.org/10.5194/cp-9-2669-2013, https://doi.org/10.5194/cp-9-2669-2013, 2013
M. Ballarotta, L. Brodeau, J. Brandefelt, P. Lundberg, and K. Döös
Clim. Past Discuss., https://doi.org/10.5194/cpd-9-297-2013, https://doi.org/10.5194/cpd-9-297-2013, 2013
Revised manuscript has not been submitted
Related subject area
Approach: Operational Oceanography | Depth range: Surface | Geographical range: All Geographic Regions | Phenomena: Sea Level
DUACS DT2018: 25 years of reprocessed sea level altimetry products
Assessing the impact of multiple altimeter missions and Argo in a global eddy-permitting data assimilation system
ENSURF: multi-model sea level forecast – implementation and validation results for the IBIROOS and Western Mediterranean regions
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.
Simon Verrier, Pierre-Yves Le Traon, and Elisabeth Remy
Ocean Sci., 13, 1077–1092, https://doi.org/10.5194/os-13-1077-2017, https://doi.org/10.5194/os-13-1077-2017, 2017
B. Pérez, R. Brouwer, J. Beckers, D. Paradis, C. Balseiro, K. Lyons, M. Cure, M. G. Sotillo, B. Hackett, M. Verlaan, and E. A. Fanjul
Ocean Sci., 8, 211–226, https://doi.org/10.5194/os-8-211-2012, https://doi.org/10.5194/os-8-211-2012, 2012
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Short summary
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.
This study investigates the resolving capabilities of the DUACS gridded products delivered...
