Articles | Volume 21, issue 1
https://doi.org/10.5194/os-21-343-2025
© 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-21-343-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
07 Feb 2025
Research article |
| 07 Feb 2025
| 07 Feb 2025
Benefits of a second tandem flight phase between two successive satellite altimetry missions for assessing instrumental stability
Michaël Ablain
CORRESPONDING AUTHOR
MAGELLIUM, Ramonville-Saint-Agne, 31520, France
Noémie Lalau
MAGELLIUM, Ramonville-Saint-Agne, 31520, France
Benoit Meyssignac
LEGOS, CNES, CNRS, IRD, Université Paul Sabatier, Toulouse, 31400, France
Robin Fraudeau
MAGELLIUM, Ramonville-Saint-Agne, 31520, France
Anne Barnoud
MAGELLIUM, Ramonville-Saint-Agne, 31520, France
Gérald Dibarboure
CNES, Toulouse, 31400, France
Alejandro Egido
ESA, ESTEC, Noordwijk, 2201 AZ, The Netherlands
Craig Donlon
ESA, ESTEC, Noordwijk, 2201 AZ, The Netherlands
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Florence Marti, Benoit Meyssignac, Victor Rousseau, Michaël Ablain, Robin Fraudeau, Alejandro Blazquez, and Sébastien Fourest
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As space geodetic observations are used to monitor the global ocean heat content change, they allow estimating the Earth energy imbalance (EEI). Over 1993–2022, the space geodetic EEI estimate shows a positive trend of 0.29 W m−2 per decade, indicating accelerated warming of the ocean in line with other independent estimates. The study highlights the importance of comparing various estimates and their uncertainties to reliably assess EEI changes.
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The estimation of regional Ocean Heat Content (OHC) is crucial for climate analysis and future climate predictions. In our study, we accurately estimate regional OHC changes in the Atlantic Ocean using satellite and in situ data. Findings reveal significant warming in the Atlantic basin from 2002 to 2020 with a mean trend of 0.17W/m², representing 230 times the power of global nuclear plants. The product has also been successfully validated in the North Atlantic basin using in situ data.
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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.
Karina von Schuckmann, Audrey Minière, Flora Gues, Francisco José Cuesta-Valero, Gottfried Kirchengast, Susheel Adusumilli, Fiammetta Straneo, Michaël Ablain, Richard P. Allan, Paul M. Barker, Hugo Beltrami, Alejandro Blazquez, Tim Boyer, Lijing Cheng, John Church, Damien Desbruyeres, Han Dolman, Catia M. Domingues, Almudena García-García, Donata Giglio, John E. Gilson, Maximilian Gorfer, Leopold Haimberger, Maria Z. Hakuba, Stefan Hendricks, Shigeki Hosoda, Gregory C. Johnson, Rachel Killick, Brian King, Nicolas Kolodziejczyk, Anton Korosov, Gerhard Krinner, Mikael Kuusela, Felix W. Landerer, Moritz Langer, Thomas Lavergne, Isobel Lawrence, Yuehua Li, John Lyman, Florence Marti, Ben Marzeion, Michael Mayer, Andrew H. MacDougall, Trevor McDougall, Didier Paolo Monselesan, Jan Nitzbon, Inès Otosaka, Jian Peng, Sarah Purkey, Dean Roemmich, Kanako Sato, Katsunari Sato, Abhishek Savita, Axel Schweiger, Andrew Shepherd, Sonia I. Seneviratne, Leon Simons, Donald A. Slater, Thomas Slater, Andrea K. Steiner, Toshio Suga, Tanguy Szekely, Wim Thiery, Mary-Louise Timmermans, Inne Vanderkelen, Susan E. Wjiffels, Tonghua Wu, and Michael Zemp
Earth Syst. Sci. Data, 15, 1675–1709, https://doi.org/10.5194/essd-15-1675-2023, https://doi.org/10.5194/essd-15-1675-2023, 2023
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The increase in ocean mass due to land ice melting is responsible for about two-thirds of the global mean sea level rise. The ocean mass variations are monitored by GRACE and GRACE Follow-On gravimetry satellites that faced instrumental issues over the last few years. In this work, we assess the robustness of these data by comparing the ocean mass gravimetry estimates to independent observations (other satellite observations, oceanographic measurements and land ice and water models).
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To ensure that the sea level is measured as accurately as possible by satellite altimeters, we must monitor possible sea level drifts caused by those instruments through comparison with other satellite altimeters or tide gauges. In this paper, we describe a method and estimate the associated uncertainties for detecting altimeter drifts over short time periods (from 2 to 10 years) through cross-comparison with other satellite altimeters and apply it to the recent Sentinel-3 A/B altimeters.
Florence Marti, Alejandro Blazquez, Benoit Meyssignac, Michaël Ablain, Anne Barnoud, Robin Fraudeau, Rémi Jugier, Jonathan Chenal, Gilles Larnicol, Julia Pfeffer, Marco Restano, and Jérôme Benveniste
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Since 2020, the Copernicus High Resolution Snow & Ice Monitoring Service has distributed snow cover maps at 20 m resolution over Europe in near-real time. These products are derived from the Sentinel-2 Earth observation mission, with a revisit time of 5 d or less (cloud-permitting). Here we show the good accuracy of the snow detection over a wide range of regions in Europe, except in dense forest regions where the snow cover is hidden by the trees.
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.
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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.
Marie Bouih, Anne Barnoud, Chunxue Yang, Andrea Storto, Alejandro Blazquez, William Llovel, Robin Fraudeau, and Anny Cazenave
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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).
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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.
Guisella Gacitúa, Jacob Lorentsen Høyer, Sten Schmidl Søbjærg, Hoyeon Shi, Sotirios Skarpalezos, Ioanna Karagali, Emy Alerskans, and Craig Donlon
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Robert R. King, Matthew J. Martin, Lucile Gaultier, Jennifer Waters, Clément Ubelmann, and Craig Donlon
Ocean Sci., 20, 1657–1676, https://doi.org/10.5194/os-20-1657-2024, https://doi.org/10.5194/os-20-1657-2024, 2024
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We use simulations of our ocean forecasting system to compare the impact of additional altimeter observations from two proposed future satellite constellations. We found that, in our system, an altimeter constellation of 12 nadir altimeters produces improved predictions of sea surface height, surface currents, temperature, and salinity compared to a constellation of 2 wide-swath altimeters.
Angélique Melet, Roderik van de Wal, Angel Amores, Arne Arns, Alisée A. Chaigneau, Irina Dinu, Ivan D. Haigh, Tim H. J. Hermans, Piero Lionello, Marta Marcos, H. E. Markus Meier, Benoit Meyssignac, Matthew D. Palmer, Ronja Reese, Matthew J. R. Simpson, and Aimée B. A. Slangen
State Planet, 3-slre1, 4, https://doi.org/10.5194/sp-3-slre1-4-2024, https://doi.org/10.5194/sp-3-slre1-4-2024, 2024
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The EU Knowledge Hub on Sea Level Rise’s Assessment Report strives to synthesize the current scientific knowledge on sea level rise and its impacts across local, national, and EU scales to support evidence-based policy and decision-making, primarily targeting coastal areas. This paper complements IPCC reports by documenting the state of knowledge of observed and 21st century projected changes in mean and extreme sea levels with more regional information for EU seas as scoped with stakeholders.
Florence Marti, Benoit Meyssignac, Victor Rousseau, Michaël Ablain, Robin Fraudeau, Alejandro Blazquez, and Sébastien Fourest
State Planet, 4-osr8, 3, https://doi.org/10.5194/sp-4-osr8-3-2024, https://doi.org/10.5194/sp-4-osr8-3-2024, 2024
Short summary
Short summary
As space geodetic observations are used to monitor the global ocean heat content change, they allow estimating the Earth energy imbalance (EEI). Over 1993–2022, the space geodetic EEI estimate shows a positive trend of 0.29 W m−2 per decade, indicating accelerated warming of the ocean in line with other independent estimates. The study highlights the importance of comparing various estimates and their uncertainties to reliably assess EEI changes.
Andrea Storto, Giulia Chierici, Julia Pfeffer, Anne Barnoud, Romain Bourdalle-Badie, Alejandro Blazquez, Davide Cavaliere, Noémie Lalau, Benjamin Coupry, Marie Drevillon, Sebastien Fourest, Gilles Larnicol, and Chunxue Yang
State Planet, 4-osr8, 12, https://doi.org/10.5194/sp-4-osr8-12-2024, https://doi.org/10.5194/sp-4-osr8-12-2024, 2024
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The variability in the manometric sea level (i.e. the sea level mass component) in three ocean basins is investigated in this study using three different methods (reanalyses, gravimetry, and altimetry in combination with in situ observations). We identify the emerging long-term signals, the consistency of the datasets, and the influence of large-scale climate modes on the regional manometric sea level variations at both seasonal and interannual timescales.
Victor Rousseau, Robin Fraudeau, Matthew Hammond, Odilon Joël Houndegnonto, Michaël Ablain, Alejandro Blazquez, Fransisco Mir Calafat, Damien Desbruyères, Giuseppe Foti, William Llovel, Florence Marti, Benoît Meyssignac, Marco Restano, and Jérôme Benveniste
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2023-236, https://doi.org/10.5194/essd-2023-236, 2023
Preprint withdrawn
Short summary
Short summary
The estimation of regional Ocean Heat Content (OHC) is crucial for climate analysis and future climate predictions. In our study, we accurately estimate regional OHC changes in the Atlantic Ocean using satellite and in situ data. Findings reveal significant warming in the Atlantic basin from 2002 to 2020 with a mean trend of 0.17W/m², representing 230 times the power of global nuclear plants. The product has also been successfully validated in the North Atlantic basin using in situ data.
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
Short summary
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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.
Karina von Schuckmann, Audrey Minière, Flora Gues, Francisco José Cuesta-Valero, Gottfried Kirchengast, Susheel Adusumilli, Fiammetta Straneo, Michaël Ablain, Richard P. Allan, Paul M. Barker, Hugo Beltrami, Alejandro Blazquez, Tim Boyer, Lijing Cheng, John Church, Damien Desbruyeres, Han Dolman, Catia M. Domingues, Almudena García-García, Donata Giglio, John E. Gilson, Maximilian Gorfer, Leopold Haimberger, Maria Z. Hakuba, Stefan Hendricks, Shigeki Hosoda, Gregory C. Johnson, Rachel Killick, Brian King, Nicolas Kolodziejczyk, Anton Korosov, Gerhard Krinner, Mikael Kuusela, Felix W. Landerer, Moritz Langer, Thomas Lavergne, Isobel Lawrence, Yuehua Li, John Lyman, Florence Marti, Ben Marzeion, Michael Mayer, Andrew H. MacDougall, Trevor McDougall, Didier Paolo Monselesan, Jan Nitzbon, Inès Otosaka, Jian Peng, Sarah Purkey, Dean Roemmich, Kanako Sato, Katsunari Sato, Abhishek Savita, Axel Schweiger, Andrew Shepherd, Sonia I. Seneviratne, Leon Simons, Donald A. Slater, Thomas Slater, Andrea K. Steiner, Toshio Suga, Tanguy Szekely, Wim Thiery, Mary-Louise Timmermans, Inne Vanderkelen, Susan E. Wjiffels, Tonghua Wu, and Michael Zemp
Earth Syst. Sci. Data, 15, 1675–1709, https://doi.org/10.5194/essd-15-1675-2023, https://doi.org/10.5194/essd-15-1675-2023, 2023
Short summary
Short summary
Earth's climate is out of energy balance, and this study quantifies how much heat has consequently accumulated over the past decades (ocean: 89 %, land: 6 %, cryosphere: 4 %, atmosphere: 1 %). Since 1971, this accumulated heat reached record values at an increasing pace. The Earth heat inventory provides a comprehensive view on the status and expectation of global warming, and we call for an implementation of this global climate indicator into the Paris Agreement’s Global Stocktake.
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
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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.
Anne Barnoud, Julia Pfeffer, Anny Cazenave, Robin Fraudeau, Victor Rousseau, and Michaël Ablain
Ocean Sci., 19, 321–334, https://doi.org/10.5194/os-19-321-2023, https://doi.org/10.5194/os-19-321-2023, 2023
Short summary
Short summary
The increase in ocean mass due to land ice melting is responsible for about two-thirds of the global mean sea level rise. The ocean mass variations are monitored by GRACE and GRACE Follow-On gravimetry satellites that faced instrumental issues over the last few years. In this work, we assess the robustness of these data by comparing the ocean mass gravimetry estimates to independent observations (other satellite observations, oceanographic measurements and land ice and water models).
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
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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.
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.
Rémi Jugier, Michaël Ablain, Robin Fraudeau, Adrien Guerou, and Pierre Féménias
Ocean Sci., 18, 1263–1274, https://doi.org/10.5194/os-18-1263-2022, https://doi.org/10.5194/os-18-1263-2022, 2022
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To ensure that the sea level is measured as accurately as possible by satellite altimeters, we must monitor possible sea level drifts caused by those instruments through comparison with other satellite altimeters or tide gauges. In this paper, we describe a method and estimate the associated uncertainties for detecting altimeter drifts over short time periods (from 2 to 10 years) through cross-comparison with other satellite altimeters and apply it to the recent Sentinel-3 A/B altimeters.
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.
Florence Marti, Alejandro Blazquez, Benoit Meyssignac, Michaël Ablain, Anne Barnoud, Robin Fraudeau, Rémi Jugier, Jonathan Chenal, Gilles Larnicol, Julia Pfeffer, Marco Restano, and Jérôme Benveniste
Earth Syst. Sci. Data, 14, 229–249, https://doi.org/10.5194/essd-14-229-2022, https://doi.org/10.5194/essd-14-229-2022, 2022
Short summary
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The Earth energy imbalance at the top of the atmosphere due to the increase in greenhouse gases and aerosol concentrations is responsible for the accumulation of energy in the climate system. With its high thermal inertia, the ocean accumulates most of this energy excess in the form of heat. The estimation of the global ocean heat content through space geodetic observations allows monitoring of the energy imbalance with realistic uncertainties to better understand the Earth’s warming climate.
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.
Zacharie Barrou Dumont, Simon Gascoin, Olivier Hagolle, Michaël Ablain, Rémi Jugier, Germain Salgues, Florence Marti, Aurore Dupuis, Marie Dumont, and Samuel Morin
The Cryosphere, 15, 4975–4980, https://doi.org/10.5194/tc-15-4975-2021, https://doi.org/10.5194/tc-15-4975-2021, 2021
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Since 2020, the Copernicus High Resolution Snow & Ice Monitoring Service has distributed snow cover maps at 20 m resolution over Europe in near-real time. These products are derived from the Sentinel-2 Earth observation mission, with a revisit time of 5 d or less (cloud-permitting). Here we show the good accuracy of the snow detection over a wide range of regions in Europe, except in dense forest regions where the snow cover is hidden by the trees.
Thomas Lavergne, Montserrat Piñol Solé, Emily Down, and Craig Donlon
The Cryosphere, 15, 3681–3698, https://doi.org/10.5194/tc-15-3681-2021, https://doi.org/10.5194/tc-15-3681-2021, 2021
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Pushed by winds and ocean currents, polar sea ice is on the move. We use passive microwave satellites to observe this motion. The images from their orbits are often put together into daily images before motion is measured. In our study, we measure motion from the individual orbits directly and not from the daily images. We obtain many more motion vectors, and they are more accurate. This can be used for current and future satellites, e.g. the Copernicus Imaging Microwave Radiometer (CIMR).
Malcolm McMillan, Alan Muir, and Craig Donlon
The Cryosphere, 15, 3129–3134, https://doi.org/10.5194/tc-15-3129-2021, https://doi.org/10.5194/tc-15-3129-2021, 2021
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We evaluate the consistency of ice sheet elevation measurements made by two satellites: Sentinel-3A and Sentinel-3B. We analysed data from the unique
tandemphase of the mission, where the two satellites flew 30 s apart to provide near-instantaneous measurements of Earth's surface. Analysing these data over Antarctica, we find no significant difference between the satellites, which is important for demonstrating that they can be used interchangeably for long-term ice sheet monitoring.
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.
Lise Kilic, Catherine Prigent, Carlos Jimenez, and Craig Donlon
Ocean Sci., 17, 455–461, https://doi.org/10.5194/os-17-455-2021, https://doi.org/10.5194/os-17-455-2021, 2021
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The Copernicus Imaging Microwave Radiometer (CIMR) is one of the high-priority satellite missions of the Copernicus program within the European Space Agency. It is designed to respond to the European Union Arctic policy. Its channels, incidence angle, precisions, and spatial resolutions have been selected to observe the Arctic Ocean with the recommendations expressed by the user communities.
In this note, we present the sensitivity analysis that has led to the choice of the CIMR channels.
Louis Marié, Fabrice Collard, Frédéric Nouguier, Lucia Pineau-Guillou, Danièle Hauser, François Boy, Stéphane Méric, Peter Sutherland, Charles Peureux, Goulven Monnier, Bertrand Chapron, Adrien Martin, Pierre Dubois, Craig Donlon, Tania Casal, and Fabrice Ardhuin
Ocean Sci., 16, 1399–1429, https://doi.org/10.5194/os-16-1399-2020, https://doi.org/10.5194/os-16-1399-2020, 2020
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With present-day techniques, ocean surface currents are poorly known near the Equator and globally for spatial scales under 200 km and timescales under 30 d. Wide-swath radar Doppler measurements are an alternative technique. Such direct surface current measurements are, however, affected by platform motions and waves. These contributions are analyzed in data collected during the DRIFT4SKIM airborne and in situ experiment, demonstrating the possibility of measuring currents from space globally.
Guillaume Dodet, Jean-François Piolle, Yves Quilfen, Saleh Abdalla, Mickaël Accensi, Fabrice Ardhuin, Ellis Ash, Jean-Raymond Bidlot, Christine Gommenginger, Gwendal Marechal, Marcello Passaro, Graham Quartly, Justin Stopa, Ben Timmermans, Ian Young, Paolo Cipollini, and Craig Donlon
Earth Syst. Sci. Data, 12, 1929–1951, https://doi.org/10.5194/essd-12-1929-2020, https://doi.org/10.5194/essd-12-1929-2020, 2020
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Sea state data are of major importance for climate studies, marine engineering, safety at sea and coastal management. However, long-term sea state datasets are sparse and not always consistent. The CCI is a program of the European Space Agency, whose objective is to realize the full potential of global Earth Observation archives in order to contribute to the ECV database. This paper presents the implementation of the first release of the Sea State CCI dataset.
Thomas Holding, Ian G. Ashton, Jamie D. Shutler, Peter E. Land, Philip D. Nightingale, Andrew P. Rees, Ian Brown, Jean-Francois Piolle, Annette Kock, Hermann W. Bange, David K. Woolf, Lonneke Goddijn-Murphy, Ryan Pereira, Frederic Paul, Fanny Girard-Ardhuin, Bertrand Chapron, Gregor Rehder, Fabrice Ardhuin, and Craig J. Donlon
Ocean Sci., 15, 1707–1728, https://doi.org/10.5194/os-15-1707-2019, https://doi.org/10.5194/os-15-1707-2019, 2019
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FluxEngine is an open-source software toolbox designed to allow for the easy and accurate calculation of air–sea gas fluxes. This article describes new functionality and capabilities, which include the ability to calculate fluxes for nitrous oxide and methane, optimisation for running FluxEngine on a stand-alone desktop computer, and extensive new features to support the in situ measurement community. Four research case studies are used to demonstrate these new features.
Anne Braakmann-Folgmann and Craig Donlon
The Cryosphere, 13, 2421–2438, https://doi.org/10.5194/tc-13-2421-2019, https://doi.org/10.5194/tc-13-2421-2019, 2019
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Snow on sea ice is a fundamental climate variable. We propose a novel approach to estimate snow depth on sea ice from satellite microwave radiometer measurements at several frequencies using neural networks (NNs). We evaluate our results with airborne snow depth measurements and compare them to three other established snow depth algorithms. We show that our NN results agree better with the airborne data than the other algorithms. This is also advantageous for sea ice thickness calculation.
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.
Thomas Block, Sabine Embacher, Christopher J. Merchant, and Craig Donlon
Geosci. Model Dev., 11, 2419–2427, https://doi.org/10.5194/gmd-11-2419-2018, https://doi.org/10.5194/gmd-11-2419-2018, 2018
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For calibration and validation purposes it is necessary to detect simultaneous data acquisitions from different spaceborne platforms. We present an algorithm and a software system which implements a general approach to resolve this problem. The multisensor matchup system (MMS) can detect simultaneous acquisitions in a large dataset (> 100 TB) and extract data for matching locations for further analysis. The MMS implements a flexible software infrastructure and allows for high parallelization.
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.
H. B. Dieng, A. Cazenave, K. von Schuckmann, M. Ablain, and B. Meyssignac
Ocean Sci., 11, 789–802, https://doi.org/10.5194/os-11-789-2015, https://doi.org/10.5194/os-11-789-2015, 2015
L. M. Goddijn-Murphy, D. K. Woolf, P. E. Land, J. D. Shutler, and C. Donlon
Ocean Sci., 11, 519–541, https://doi.org/10.5194/os-11-519-2015, https://doi.org/10.5194/os-11-519-2015, 2015
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We describe the OceanFlux Greenhouse Gases methodology for creating an ocean surface CO2 climatology. In situ measurements valid for instantaneous sea surface temperature (SST) were recomputed using a more consistent and averaged SST. The results were normalised to year 2010, averaged by month, and interpolated onto a global 1°×1° grid. The 12 monthly distributions of ocean surface CO2 (see supplement) can be used in air-sea gas flux calculations together with climatologies of other variables.
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.
P. E. Land, J. D. Shutler, R. D. Cowling, D. K. Woolf, P. Walker, H. S. Findlay, R. C. Upstill-Goddard, and C. J. Donlon
Biogeosciences, 10, 8109–8128, https://doi.org/10.5194/bg-10-8109-2013, https://doi.org/10.5194/bg-10-8109-2013, 2013
Related subject area
Approach: Remote Sensing | Properties and processes: Sea level, tides, tsunamis and surges
Understanding uncertainties in the satellite altimeter measurement of coastal sea level: insights from a round-robin analysis
Unsupervised classification of the northwestern European seas based on satellite altimetry data
Statistical analysis of dynamic behavior of continental shelf wave motions in the northern South China Sea
Spatial and temporal variability in mode-1 and mode-2 internal solitary waves from MODIS-Terra sun glint off the Amazon shelf
Florence Birol, François Bignalet-Cazalet, Mathilde Cancet, Jean-Alexis Daguze, Wassim Fkaier, Ergane Fouchet, Fabien Léger, Claire Maraldi, Fernando Niño, Marie-Isabelle Pujol, and Ngan Tran
Ocean Sci., 21, 133–150, https://doi.org/10.5194/os-21-133-2025, https://doi.org/10.5194/os-21-133-2025, 2025
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We take advantage of the availability of several algorithms for most of the terms/corrections used to calculate altimetry sea level data to quantify and analyze the sources of uncertainty associated with the approach to the coast. The results highlight their hierarchy. Tidal corrections and mean sea surface height contribute to coastal sea level data uncertainties. Improving the retracking algorithm is today the main factor to bring accurate altimetry sea level data closer to the shore.
Lea Poropat, Dani Jones, Simon D. A. Thomas, and Céline Heuzé
Ocean Sci., 20, 201–215, https://doi.org/10.5194/os-20-201-2024, https://doi.org/10.5194/os-20-201-2024, 2024
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In this study we use a machine learning method called a Gaussian mixture model to divide part of the ocean (northwestern European seas and part of the Atlantic Ocean) into regions based on satellite observations of sea level. This helps us study each of these regions separately and learn more about what causes sea level changes there. We find that the ocean is first divided based on bathymetry and then based on other features such as water masses and typical atmospheric conditions.
Junyi Li, Tao He, Quanan Zheng, Ying Xu, and Lingling Xie
Ocean Sci., 19, 1545–1559, https://doi.org/10.5194/os-19-1545-2023, https://doi.org/10.5194/os-19-1545-2023, 2023
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This study aims to analyze the statistical behavior of the continental shelf wave motions, including continental shelf waves (CSWs) and arrested topographic waves (ATWs), in the northern South China Sea. The cross-shelf structure of along-track SLAs indicates that Mode 1 of CSWs is the predominant component trapped in the area shallower than about 200 m. The cross-shelf structures of CSWs and ATWs illustrate that the methods are suitable for observing the dynamic behavior of the CSWs.
Carina Regina de Macedo, Ariane Koch-Larrouy, José Carlos Bastos da Silva, Jorge Manuel Magalhães, Carlos Alessandre Domingos Lentini, Trung Kien Tran, Marcelo Caetano Barreto Rosa, and Vincent Vantrepotte
Ocean Sci., 19, 1357–1374, https://doi.org/10.5194/os-19-1357-2023, https://doi.org/10.5194/os-19-1357-2023, 2023
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We focus on the internal solitary waves (ISWs) off the Amazon shelf, their velocity, and their variability in seasonal and tidal cycles. The analysis is based on a large remote-sensing data set. The region is newly described as a hot spot for ISWs with mode-2 internal tide wavelength. The wave activity is higher during spring tides. The mode-1 waves located in the region influenced by the North Equatorial Counter Current showed a velocity/wavelength 14.3 % higher during the boreal summer/fall.
Cited articles
Ablain, M., Philipps, S., Picot, N., and Bronner, E.: Jason-2 Global Statistical Assessment and Cross-Calibration with Jason-1, Mar. Geod., 33, 162–185, https://doi.org/10.1080/01490419.2010.487805, 2010. a
Ablain, M., Jugier, R., Zawadzki, L., and Picot, N.: Estimating any altimeter GMSL drifts between 1993 and 2018 by comparison with tide gauges, https://www.geomatlab.tuc.gr/fileadmin/users_data/geomatlab/international_review_workshop_2018/presentations/01_Monday/Session_01/06_S1_23_Ablain_et_al.pdf (last access: 27 January 2025), 2018. a, b, c, d
Ablain, M., Meyssignac, B., Zawadzki, L., Jugier, R., Ribes, A., Spada, G., Benveniste, J., Cazenave, A., and Picot, N.: Uncertainty in satellite estimates of global mean sea-level changes, trend and acceleration, Earth Syst. Sci. Data, 11, 1189–1202, https://doi.org/10.5194/essd-11-1189-2019, 2019. a, b, c, d, e, f, g
Ablain, M., Jugier, R., Marti, F., Dibarboure, G., Couhert, A., Meyssignac, B., and Cazenave, A.: Benefit of a second calibration phase to estimate the relative global and regional mean sea level drifts between Jason-3 and Sentinel-6a, preprint, Oceanography, https://doi.org/10.1002/essoar.10502856.1, 2020. a
Barnoud, A., Pfeffer, J., Guérou, A., Frery, M., Siméon, M., Cazenave, A., Chen, J., Llovel, W., Thierry, V., Legeais, J., and Ablain, M.: Contributions of Altimetry and Argo to Non‐Closure of the Global Mean Sea Level Budget Since 2016, Geophys. Res. Lett., 48, e2021GL092824, https://doi.org/10.1029/2021GL092824, 2021. a
Cadier, E., Courcol, B., Prandi, P., Quet, V., Moreau, T., Maraldi, C., Bignalet-Cazalet, F., Dinardo, S., Martin-Puig, C., and Donlon, C.: Assessment of Sentinel-6MF low resolution numerical retracker over ocean: Continuity on reference orbit and improvements, Adv. Space Res., 75, 30–52, https://doi.org/10.1016/j.asr.2024.11.045, 2024. a, b, c
Centre National d'Etudes Spatiales (CNES): OSTM/Jason-2 CalVal Plan 2008, https://drive.google.com/file/d/12fkVRx4EMYug5lni-5zcidjtexanTAcc/view?usp=drive_link (last access: 27 January 2025), 2008. a
CNES: AVISO FTP access to altimetry products, https://www.aviso.altimetry.fr/en/data/data-access/ftp.html, last access: 31 March 2025. a
Couhert, A., Cerri, L., Legeais, J.-F., Ablain, M., Zelensky, N. P., Haines, B. J., Lemoine, F. G., Bertiger, W. I., Desai, S. D., and Otten, M.: Towards the 1mm/y stability of the radial orbit error at regional scales, Adv. Space Res., 55, 2–23, https://doi.org/10.1016/j.asr.2014.06.041, 2015. a
Dibarboure, G., Schaeffer, P., Escudier, P., Pujol, M.-I., Legeais, J. F., Faugère, Y., Morrow, R., Willis, J. K., Lambin, J., Berthias, J. P., and Picot, N.: Finding Desirable Orbit Options for the “Extension of Life” Phase of Jason-1, Mar. Geod., 35, 363–399, https://doi.org/10.1080/01490419.2012.717854, 2012. a
Dibarboure, G., Boy, F., Desjonqueres, J. D., Labroue, S., Lasne, Y., Picot, N., Poisson, J. C., and Thibaut, P.: Investigating Short-Wavelength Correlated Errors on Low-Resolution Mode Altimetry, J. Atmos. Ocean. Technol., 31, 1337–1362, https://doi.org/10.1175/JTECH-D-13-00081.1, 2014. a
Dieng, H. B., Cazenave, A., Meyssignac, B., and Ablain, M.: New estimate of the current rate of sea level rise from a sea level budget approach, Geophys. Res. Lett., 44, 3744–3751, https://doi.org/10.1002/2017gl073308, 2017. a
Dinardo, S., Maraldi, C., Daguze, J.-A., Amraoui, S., Boy, F., Moreau, T., and Picot, N.: Sentinel-6 MF Poseidon-4 Radar Altimeter In-Flight Calibration and Performances Monitoring, CNES, https://doi.org/10.24400/527896/A03-2022.3377, 2022. a
Donlon, C. J., O’Carroll, A., Smith, D., Scharroo, R., Bourg, L., Kwiatkowska, E., Merchant, C., Sathyendranath, S., Labroue, S., and Larnicol, G.: Scientific Justification for a Tandem Mission between Sentinel-3A and Sentinel-3B during the E1 Commissioning Phase, European Space Agency Technical Note EOP-SM/3057/CD-cd, Issue 4.3, European Space Agency, Noordwijk, The Netherlands, 2017. a
Donlon, C., Scharroo, R., Willis, J., Leuliette, E., Bonnefond, P., Picot, N., Schrama, E., and Brown, S.: Sentinel-6A/B/Jason-3 Tandem Phase Configurations; JC-TN-ESA-MI-0876 V2.0; European Space Agency, Noordwijk, The Netherlands, 2019. a
Donlon, C. J., Cullen, R., Giulicchi, L., Vuilleumier, P., Francis, C. R., Kuschnerus, M., Simpson, W., Bouridah, A., Caleno, M., Bertoni, R., Rancaño, J., Pourier, E., Hyslop, A., Mulcahy, J., Knockaert, R., Hunter, C., Webb, A., Fornari, M., Vaze, P., Brown, S., Willis, J., Desai, S., Desjonqueres, J.-D., Scharroo, R., Martin-Puig, C., Leuliette, E., Egido, A., Smith, W. H., Bonnefond, P., Le Gac, S., Picot, N., and Tavernier, G.: The Copernicus Sentinel-6 mission: Enhanced continuity of satellite sea level measurements from space, Remote Sens. Environ., 258, 112395, https://doi.org/10.1016/j.rse.2021.112395, 2021. a
Dorandeu, J., Ablain, M., Faugère, Y., Mertz, F., Soussi, B., and Vincent, P.: Jason-1 global statistical evaluation and performance assessment: Calibration and cross-calibration results, Mar. Geod., 27, 345–372, https://doi.org/10.1080/01490410490889094, 2004. a
Ferrier, C.: Jason-3 mission overview, OSTST 2023, CNES, https://doi.org/10.24400/527896/A03-2023.3887, 2023. a, b, c
Guérou, A., Meyssignac, B., Prandi, P., Ablain, M., Ribes, A., and Bignalet-Cazalet, F.: Current observed global mean sea level rise and acceleration estimated from satellite altimetry and the associated measurement uncertainty, Ocean Sci., 19, 431–451, https://doi.org/10.5194/os-19-431-2023, 2023. a, b, c, d, e
Hakuba, M. Z., Frederikse, T., and Landerer, F. W.: Earth's Energy Imbalance From the Ocean Perspective (2005–2019), Geophys. Res. Lett., 48, e2021GL093624, https://doi.org/10.1029/2021GL093624, 2021. a
Henry, O., Ablain, M., Meyssignac, B., Cazenave, A., Masters, D., Nerem, S., and Garric, G.: Effect of the processing methodology on satellite altimetry-based global mean sea level rise over the Jason-1 operating period, J. Geodesy, 88, 351–361, https://doi.org/10.1007/s00190-013-0687-3, 2014. a, b
Jugier, R., Ablain, M., Fraudeau, R., Guerou, A., and Féménias, P.: On the uncertainty associated with detecting global and local mean sea level drifts on Sentinel-3A and Sentinel-3B altimetry missions, Ocean Sci., 18, 1263–1274, https://doi.org/10.5194/os-18-1263-2022, 2022. a, b, c, d
Marti, F., Blazquez, A., Meyssignac, B., Ablain, M., Barnoud, A., Fraudeau, R., Jugier, R., Chenal, J., Larnicol, G., Pfeffer, J., Restano, M., and Benveniste, J.: Monitoring the ocean heat content change and the Earth energy imbalance from space altimetry and space gravimetry, Earth Syst. Sci. Data, 14, 229–249, https://doi.org/10.5194/essd-14-229-2022, 2022. a
Marti, F., Meyssignac, B., Rousseau, V., Ablain, M., Fraudeau, R., Blazquez, A., and Fourest, S.: Monitoring global ocean heat content from space geodetic observations to estimate the Earth energy imbalance, in: 8th edition of the Copernicus Ocean State Report (OSR8), edited by: von Schuckmann, K., Moreira, L., Grégoire, M., Marcos, M., Staneva, J., Brasseur, P., Garric, G., Lionello, P., Karstensen, J., and Neukermans, G., Copernicus Publications, State Planet, 4-osr8, 3, https://doi.org/10.5194/sp-4-osr8-3-2024, 2024. a
Mertikas, S. P., Donlon, C., Matsakis, D., Mavrocordatos, C., Altamimi, Z., Kokolakis, C., and Tripolitsiotis, A.: Fiducial reference systems for time and coordinates in satellite altimetry, Adv. Space Res., 68, 1140–1160, https://doi.org/10.1016/j.asr.2020.05.014, 2021. a
Meyssignac, B., Ablain, M., Guérou, A., Prandi, P., Barnoud, A., Blazquez, A., Fourest, S., Rousseau, V., Bonnefond, P., Cazenave, A., Chenal, J., Dibarboure, G., Donlon, C., Benveniste, J., Sylvestre-Baron, A., and Vinogradova, N.: How accurate is accurate enough for measuring sea-level rise and variability, Nat. Clim. Change, 13, 796–803, https://doi.org/10.1038/s41558-023-01735-z, 2023. a
Rudenko, S., Dettmering, D., Zeitlhöfler, J., Alkahal, R., Upadhyay, D., and Bloßfeld, M.: Radial Orbit Errors of Contemporary Altimetry Satellite Orbits, Surv. Geophys., 44, 705–737, https://doi.org/10.1007/s10712-022-09758-5, 2023. a
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Short summary
This study proposes a novel cross-validation method to assess the instrumental stability in sea level trends. The method involves implementing a second tandem flight phase between two successive altimeter missions a few years after the first phase. The trend in systematic instrumental differences made during the two tandem phases can be estimated below ± 0.1 mm yr-1 (16–84 % confidence level) on a global scale for time intervals between the tandem phases of 4 years or more.
This study proposes a novel cross-validation method to assess the instrumental stability in sea...
