Articles | Volume 12, issue 1 
            
                
                    
            
            
            https://doi.org/10.5194/os-12-1-2016
                    © Author(s) 2016. This work is distributed under 
the Creative Commons Attribution 3.0 License.
                the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-12-1-2016
                    © Author(s) 2016. This work is distributed under 
the Creative Commons Attribution 3.0 License.
                the Creative Commons Attribution 3.0 License.
Spatial scales of temperature and salinity variability estimated from Argo observations
F. Ninove
                                            Ifremer, Technopole Brest Iroise, Z.I. de la Pointe du Diable, 29280   Plouzané, France
                                        
                                    
                                            Mercator Ocean, Parc technologique du Canal, 8–10 rue Hermès, 31520 Ramonville-Saint-Agne, France
                                        
                                    P.-Y. Le Traon
CORRESPONDING AUTHOR
                                            
                                    
                                            Ifremer, Technopole Brest Iroise, Z.I. de la Pointe du Diable, 29280   Plouzané, France
                                        
                                    
                                            Mercator Ocean, Parc technologique du Canal, 8–10 rue Hermès, 31520 Ramonville-Saint-Agne, France
                                        
                                    E. Remy
                                            Mercator Ocean, Parc technologique du Canal, 8–10 rue Hermès, 31520 Ramonville-Saint-Agne, France
                                        
                                    S. Guinehut
                                            CLS, Parc Technologique du Canal, 8–10 rue Hermès, 31520 Ramonville-Saint-Agne, France
                                        
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                                    Ocean Sci., 21, 1329–1347, https://doi.org/10.5194/os-21-1329-2025, https://doi.org/10.5194/os-21-1329-2025, 2025
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                                                By providing all weather, global, and real-time observations of sea level, a key variable to constrain ocean analysis and forecasting systems, satellite altimetry has had a profound impact on the development of operational oceanography. This paper provides an overview of the development and evolution of satellite altimetry and operational oceanography over the past 20 years from the launch of Jason-1 in 2001 to the launch of SWOT (Surface Water and Ocean Topography) in 2022.
                                            
                                            
                                        Antonio Novellino, Pierre-Yves Le Traon, and Andy Moore
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                                                This paper discusses the vital role of observations in ocean predictions and forecasting, highlighting the need for effective access, management, and integration of data to improve models and decision-making. The paper also explores opportunities for standardizing protocols and the potential of citizen-based, cost-effective data collection methods.
                                            
                                            
                                        Ségolène Berthou, John Siddorn, Vivian Fraser-Leonhardt, Pierre-Yves Le Traon, and Ibrahim Hoteit
                                    State Planet, 5-opsr, 20, https://doi.org/10.5194/sp-5-opsr-20-2025, https://doi.org/10.5194/sp-5-opsr-20-2025, 2025
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                                                Ocean forecasting is traditionally done independently from atmospheric, wave, or river modelling. We discuss the benefits and challenges of bringing all these modelling systems together for ocean forecasting.
                                            
                                            
                                        Pierre-Yves Le Traon, Antonio Novellino, and Andrew M. Moore
                                    State Planet, 5-opsr, 7, https://doi.org/10.5194/sp-5-opsr-7-2025, https://doi.org/10.5194/sp-5-opsr-7-2025, 2025
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                                                Ocean prediction relies on the integration between models and satellite and in situ observations through data assimilation techniques. The authors discuss the role of observations in operational ocean forecasting systems, describing the state of the art of satellite and in situ observing networks and defining the paths for addressing multi-scale monitoring and forecasting.
                                            
                                            
                                        Aliette Chenal, Gilles Garric, Charles-Emmanuel Testut, Mathieu Hamon, Giovanni Ruggiero, Florent Garnier, and Pierre-Yves Le Traon
                                        EGUsphere, https://doi.org/10.5194/egusphere-2024-3633, https://doi.org/10.5194/egusphere-2024-3633, 2024
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                                                This study proposes to improve the representation of ice and snow volumes in the Arctic and Antarctic based on a novel multivariate assimilation method using freeboard radar and snow depth satellite data. The approach leads to an improved sea ice and snow volume representation, even during summer when satellite data is limited. The performance of the assimilated system is better in the Arctic than in Antarctica, where ocean/ice interactions play a key role.
                                            
                                            
                                        Mounir Benkiran, Pierre-Yves Le Traon, Elisabeth Rémy, and Yann Drillet
                                        EGUsphere, https://doi.org/10.5194/egusphere-2024-420, https://doi.org/10.5194/egusphere-2024-420, 2024
                                    Preprint archived 
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                                                The assimilation of altimetry data corrects and improves the forecast of a global ocean forecasting system. Until now, the use of altimetry observations from nadir altimeters has had a major impact on the quality of ocean forecasts. Our study shows that the use of observations from swath altimeters will have a greater impact than the quality of these forecasts and will better constrain mesoscale structures.
                                            
                                            
                                        Karina von Schuckmann, Lorena Moreira, and Pierre-Yves Le Traon
                                    State Planet, 1-osr7, 1, https://doi.org/10.5194/sp-1-osr7-1-2023, https://doi.org/10.5194/sp-1-osr7-1-2023, 2023
                            Stefania A. Ciliberti, Enrique Alvarez Fanjul, Jay Pearlman, Kirsten Wilmer-Becker, Pierre Bahurel, Fabrice Ardhuin, Alain Arnaud, Mike Bell, Segolene Berthou, Laurent Bertino, Arthur Capet, Eric Chassignet, Stefano Ciavatta, Mauro Cirano, Emanuela Clementi, Gianpiero Cossarini, Gianpaolo Coro, Stuart Corney, Fraser Davidson, Marie Drevillon, Yann Drillet, Renaud Dussurget, Ghada El Serafy, Katja Fennel, Marcos Garcia Sotillo, Patrick Heimbach, Fabrice Hernandez, Patrick Hogan, Ibrahim Hoteit, Sudheer Joseph, Simon Josey, Pierre-Yves Le Traon, Simone Libralato, Marco Mancini, Pascal Matte, Angelique Melet, Yasumasa Miyazawa, Andrew M. Moore, Antonio Novellino, Andrew Porter, Heather Regan, Laia Romero, Andreas Schiller, John Siddorn, Joanna Staneva, Cecile Thomas-Courcoux, Marina Tonani, Jose Maria Garcia-Valdecasas, Jennifer Veitch, Karina von Schuckmann, Liying Wan, John Wilkin, and Romane Zufic
                                    State Planet, 1-osr7, 2, https://doi.org/10.5194/sp-1-osr7-2-2023, https://doi.org/10.5194/sp-1-osr7-2-2023, 2023
                            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).
                                            
                                            
                                        Benoît Tranchant, Elisabeth Remy, Eric Greiner, and Olivier Legalloudec
                                    Ocean Sci., 15, 543–563, https://doi.org/10.5194/os-15-543-2019, https://doi.org/10.5194/os-15-543-2019, 2019
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                                                This work deals with the use of sea surface salinity measurements from space in the context of operational oceanography. The salinity plays an important role in the ocean–atmosphere coupling, especially when an El Niño event occurs in the tropical Pacific. However, it is still difficult to use such data in ocean models due to a large extent to large-scales biases. This study shows that from recent data with a suitable bias correction scheme, it is possible to improve our forecast skill.
                                            
                                            
                                        Antonio Bonaduce, Mounir Benkiran, Elisabeth Remy, Pierre Yves Le Traon, and Gilles Garric
                                    Ocean Sci., 14, 1405–1421, https://doi.org/10.5194/os-14-1405-2018, https://doi.org/10.5194/os-14-1405-2018, 2018
                            Jean-Michel Lellouche, Eric Greiner, Olivier Le Galloudec, Gilles Garric, Charly Regnier, Marie Drevillon, Mounir Benkiran, Charles-Emmanuel Testut, Romain Bourdalle-Badie, Florent Gasparin, Olga Hernandez, Bruno Levier, Yann Drillet, Elisabeth Remy, and Pierre-Yves Le Traon
                                    Ocean Sci., 14, 1093–1126, https://doi.org/10.5194/os-14-1093-2018, https://doi.org/10.5194/os-14-1093-2018, 2018
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                                                In the coming decades, a strong growth of the ocean economy is expected. Scientific advances in operational oceanography will play a crucial role in addressing many environmental challenges and in the development of ocean-related economic activities. In this context, remarkable improvements have been achieved with the current Mercator Ocean system. 3-D water masses, sea level, sea ice and currents have been improved, and thus major oceanic variables are hard to distinguish from the data.
                                            
                                            
                                        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
                            V. Turpin, E. Remy, and P. Y. Le Traon
                                    Ocean Sci., 12, 257–274, https://doi.org/10.5194/os-12-257-2016, https://doi.org/10.5194/os-12-257-2016, 2016
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                                                Argo profiling floats are continuously sampling the world ocean, providing temperature and salinity profiles of up to 2000 m depths. This article addresses the impact of the current Argo array on real-time ocean analyses and forecasts. One-year observing system experiments were carried out with the 0.25° global Mercator Ocean monitoring and forecasting system. The improvement due to the assimilation of the Argo profiles is estimated globally and regionally, showing a significant positive impact.
                                            
                                            
                                        K. von Schuckmann, J.-B. Sallée, D. Chambers, P.-Y. Le Traon, C. Cabanes, F. Gaillard, S. Speich, and M. Hamon
                                    Ocean Sci., 10, 547–557, https://doi.org/10.5194/os-10-547-2014, https://doi.org/10.5194/os-10-547-2014, 2014
                            P. Y. Le Traon
                                    Ocean Sci., 9, 901–915, https://doi.org/10.5194/os-9-901-2013, https://doi.org/10.5194/os-9-901-2013, 2013
                            Related subject area
            Approach: In situ Observations | Depth range: All Depths | Geographical range: All Geographic Regions | Phenomena: Temperature, Salinity and Density Fields
            
                    
                        
                            
                            
                                     
                                The CORA 5.2 dataset for global in situ temperature and salinity measurements: data description and validation
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                World Ocean Circulation Experiment – Argo Global Hydrographic Climatology
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                How essential are Argo observations to constrain a global ocean data assimilation system?
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                On the observability of turbulent transport rates by Argo: supporting evidence from an inversion experiment
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Global representation of tropical cyclone-induced short-term ocean thermal changes using Argo data
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                The instability of diffusive convection and its implication for the thermohaline staircases in the deep Arctic Ocean
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                The CORA dataset: validation and diagnostics of in-situ ocean temperature and salinity measurements
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                How well can we derive Global Ocean Indicators from Argo data?
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Comparison of the fall rate and structure of recent T-7 XBT manufactured by Sippican and TSK
                                
                            
                            
                        
                    
                    
            
        
        Tanguy Szekely, Jérôme Gourrion, Sylvie Pouliquen, and Gilles Reverdin
                                    Ocean Sci., 15, 1601–1614, https://doi.org/10.5194/os-15-1601-2019, https://doi.org/10.5194/os-15-1601-2019, 2019
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                                                This study is an attempt to validate the quality of a global temperature and salinity dataset by estimating the effects of measurement errors on the estimated ocean variability. The study shows that the effects of the measurement errors decrease during the quality control process and are almost null for the delayed-time-mode quality-controlled dataset.
                                            
                                            
                                        Viktor Gouretski
                                    Ocean Sci., 14, 1127–1146, https://doi.org/10.5194/os-14-1127-2018, https://doi.org/10.5194/os-14-1127-2018, 2018
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                                                The new gridded WOCE-Argo Global Hydrographic Climatology (WAGHC) is described and compared with the NOAA WOA13 atlas. The monthly fields of temperature and salinity for 65 depth levels have a 1/4° spatial resolution. Two versions of the climatology were produced and differ with respect to the spatial interpolation  performed on isobaric or isopycnal surfaces, respectively. The climatology characterizes the thermohaline state of the world ocean for the time period from 2008 to 2012.
                                            
                                            
                                        V. Turpin, E. Remy, and P. Y. Le Traon
                                    Ocean Sci., 12, 257–274, https://doi.org/10.5194/os-12-257-2016, https://doi.org/10.5194/os-12-257-2016, 2016
                                    Short summary
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                                                Argo profiling floats are continuously sampling the world ocean, providing temperature and salinity profiles of up to 2000 m depths. This article addresses the impact of the current Argo array on real-time ocean analyses and forecasts. One-year observing system experiments were carried out with the 0.25° global Mercator Ocean monitoring and forecasting system. The improvement due to the assimilation of the Argo profiles is estimated globally and regionally, showing a significant positive impact.
                                            
                                            
                                        G. Forget, D. Ferreira, and X. Liang
                                    Ocean Sci., 11, 839–853, https://doi.org/10.5194/os-11-839-2015, https://doi.org/10.5194/os-11-839-2015, 2015
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                                                Results from the ECCO v4 ocean state estimate identify the constraint of fitting Argo profiles as an effective observational basis for inverse estimation of regional turbulent transport rates. The estimated parameters' geography is physically plausible and exhibits close connections with the observed upper-ocean stratification. They yield a clear reduction in the model drift away from observations over multi-century-long simulations, including for independent biochemistry variables.
                                            
                                            
                                        L. Cheng, J. Zhu, and R. L. Sriver
                                    Ocean Sci., 11, 719–741, https://doi.org/10.5194/os-11-719-2015, https://doi.org/10.5194/os-11-719-2015, 2015
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                                                1. Argo floats were used to examine tropical cyclone (TC) induced ocean thermal changes on the global scale by comparing temperature profiles before and after TC passage. 
2. Global average of the vertical structure of the average ocean thermal response for two different categories: tropical storms/depressions (TS/TD) and hurricanes were presented.
3. Significant differences between weak storm (TS/TD) and strong storm (hurricane) were found.
                                            
                                            
                                        S.-Q. Zhou, L. Qu, Y.-Z. Lu, and X.-L. Song
                                    Ocean Sci., 10, 127–134, https://doi.org/10.5194/os-10-127-2014, https://doi.org/10.5194/os-10-127-2014, 2014
                            C. Cabanes, A. Grouazel, K. von Schuckmann, M. Hamon, V. Turpin, C. Coatanoan, F. Paris, S. Guinehut, C. Boone, N. Ferry, C. de Boyer Montégut, T. Carval, G. Reverdin, S. Pouliquen, and P.-Y. Le Traon
                                    Ocean Sci., 9, 1–18, https://doi.org/10.5194/os-9-1-2013, https://doi.org/10.5194/os-9-1-2013, 2013
                            K. von Schuckmann and P.-Y. Le Traon
                                    Ocean Sci., 7, 783–791, https://doi.org/10.5194/os-7-783-2011, https://doi.org/10.5194/os-7-783-2011, 2011
                            S. Kizu, C. Sukigara, and K. Hanawa
                                    Ocean Sci., 7, 231–244, https://doi.org/10.5194/os-7-231-2011, https://doi.org/10.5194/os-7-231-2011, 2011
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                Short summary
            Argo floats are one of the main components of the in situ observation network in the ocean. Nowadays, more than 3500 profiling floats are sampling the world ocean. In this study, they are used to characterize spatial scales of temperature and salinity variations from the surface down to 1500m. The scales appear to be anisotropic and vary from about 100km at high latitudes to 700km in the Indian and Pacific equatorial and tropical regions.
            Argo floats are one of the main components of the in situ observation network in the ocean....
            
         
 
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
             
             
            