Articles | Volume 17, issue 3
Research article 17 Jun 2021
Research article | 17 Jun 2021
The new CNES-CLS18 global mean dynamic topography
Sandrine Mulet et al.
No articles found.
Pierre Prandi, Jean-Christophe Poisson, Yannice Faugère, Amandine Guillot, and Gérald Dibarboure
Earth Syst. Sci. Data, 13, 5469–5482,Short summary
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.
Estrella Olmedo, Verónica González-Gambau, Antonio Turiel, Cristina González-Haro, Aina García-Espriu, Marilaure Gregoire, Aida Álvera-Azcárate, Luminita Buga, and Marie-Hélène Rio
Earth Syst. Sci. Data Discuss.,
Preprint under review for ESSDShort summary
We present the first dedicated satellite salinity product in the Black Sea. We use the measurements provided by the European Soil Moisture and Ocean Salinity mission. We introduce enhanced algorithms for dealing with the contamination produced by the Radio Frequency Interferences that strongly affect this basin. We also provide a complete quality assessment of the new product and give an estimated accuracy of it.
Mounir Benkiran, Pierre-Yves Le Traon, and Gérald Dibarboure
Ocean Sci. Discuss.,
Preprint under review for OSShort summary
The SSH analysis and 7-day 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 depths 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).
Cori Pegliasco, Antoine Delepoulle, Rosemary Morrow, Yannice Faugère, and Gérald Dibarboure
Earth Syst. Sci. Data Discuss.,
Preprint under review for ESSDShort summary
The new global Mesoscale Eddy Trajectories Atlases (META3.1exp) provide the eddies' identification and trajectories from altimetry maps. These atlases are an improvement and the continuity 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 un asset for multi-disciplinary studies.
Clément Ubelmann, Loren Carrere, Chloé Durand, Gérald Dibarboure, Yannice Faugère, Maxime Ballarotta, Frédéric Briol, and Florent Lyard
Ocean Sci. Discuss.,
Preprint under review for OSShort summary
The signature of internal tides becomes an important component for high-resolution altimetry over the 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 supposed 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.
Louis de Montera, Henrick Berger, Romain Husson, Pascal Appelghem, Laurent Guerlou, and Mauricio Fragoso
Wind Energ. Sci. Discuss.,
Revised manuscript under review for WESShort summary
This article presents a novel method to improve offshore surface wind speeds estimated by Synthetic Aperture Radar satellites and extrapolate them to higher altitudes. It can provide maps of the offshore extractible wind power up to 200 m and thus complement numerical models, especially in coastal areas. The method uses geometrical parameters of the sensor and parameters related to the atmospheric stability, combining them with machine learning. The final accuracy at 200 m is within 4 %.
Florent H. Lyard, Damien J. Allain, Mathilde Cancet, Loren Carrère, and Nicolas Picot
Ocean Sci., 17, 615–649,Short summary
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,Short summary
Internal tides can have a signature of several centimeters at the ocean surface and need to be corrected from altimeter measurements. We present a detailed validation of several internal-tide models using existing satellite altimeter databases. The analysis focuses on the main diurnal and semidiurnal tidal constituents. Results show the interest of the methodology proposed, the quality of the internal-tide models tested and their positive contribution for estimating an accurate sea level.
Guillaume Taburet, Antonio Sanchez-Roman, Maxime Ballarotta, Marie-Isabelle Pujol, Jean-François Legeais, Florent Fournier, Yannice Faugere, and Gerald Dibarboure
Ocean Sci., 15, 1207–1224,Short summary
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,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.
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,Short summary
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,Short summary
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,
Lionel Zawadzki, Michaël Ablain, Loren Carrere, Richard D. Ray, Nikita P. Zelensky, Florent Lyard, Amandine Guillot, and Nicolas Picot
Ocean Sci. Discuss.,
Preprint withdrawnShort summary
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.
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,Short summary
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.
Ardhuin, F., Marié, L., Rascle, N., Forget, P., and Roland, A.: Observation and Estimation of Lagrangian, Stokes, and Eulerian Currents Induced by Wind and Waves at the Sea Surface, J. Phys. Oceanogr., 39, 2820–2838, 2009.
Artana, C., Ferrari, R., Bricaud, C., Lellouche, J.-M., Garric, G., Sennéchael, N., Lee, J.-H., Park, Y.-H., and Provost, C.: Twenty-five years of Mercator ocean reanalysis GLORYS12 at Drake Passage: Velocity assessment and total volume transport, Adv. Space Res., ISSN 0273-1177, https://doi.org/10.1016/j.asr.2019.11.033, 2019.
AVISO + MDT: Combined mean dynamic topography – MDT CNES-CLS18, available at: https://www.aviso.altimetry.fr/en/data/products/auxiliary-products/mdt.html, last access: 1 June 2021.
Bingham, R., Haines, K., and Hughes, C.: Calculating the Ocean's Mean Dynamic Topography from a Mean Sea Surface and a Geoid, J. Atmos. Ocean. Tech., 25, 1808–1822, https://doi.org/10.1175/2008JTECHO568.1, 2008.
Bruinsma, S. L., Förste, C., Abrikosov, O., Lemoine, J.-M., Marty, J.-C., Mulet, S., Rio, M.-H., and Bonvalot, S.: ESA's satellite-only gravity field model via the direct approach based on all GOCE data, Geophys. Res. Lett., 41, 7508–7514, https://doi.org/10.1002/2014GL062045, 2014.
Caballero, A., Mulet, S., Ayoub, N., Manso-Narvarte, I., Davila, X., Boone, C., Toublanc, F., and Rubio, A.: Integration of HF Radar Observations for an Enhanced Coastal Mean Dynamic Topography, Front. Mar. Sci., 7, 588713, https://doi.org/10.3389/fmars.2020.588713, 2020.
Cabanes, C., Grouazel, A., von Schuckmann, K., Hamon, M., Turpin V., Coatanoan, C., Paris, F., Guinehut, S., Boone, C., Ferry, N., De Boyer Montégut, C., Carval, T., Reverdin, G., Pouliquen, S., and Le Traon, P. Y.: The CORA dataset: validation and diagnostics of in-situ ocean temperature and salinity measurements, Ocean Sci., 9, 1–18, https://doi.org/10.5194/os-9-1-2013, 2013.
Cancet, M., Griffin, D., Cahill, M., Chapron, B., Johannessen, J., and Donlon, C.: Evaluation of GlobCurrent surface ocean current products: A case study in Australia, Remote Sens. Environ., 220, 71–93, https://doi.org/10.1016/j.rse.2018.10.029, 2019.
Chapron, B. and the GlobCurrent Team: GlobCurrent Analyses and Interpretation Framework, Technical Report, Deliverable for the ESA Study Contract Number 4000109513/13/I-LG, available at: https://globcurrent.nersc.no/system/files/pubdeliver/GlobCurrent_D-140_TN-1_v2.pdf (last access: 7 June 2021), November 2017.
Chapron, B., Collard, F., and Ardhuin, F.: Direct measurements of ocean surface velocity from space: Interpretation and validation, J. Geophys. Res.-Oceans, 110, C07008, https://doi.org/10.1029/2004JC002809, 2005.
De Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A., and Iudicone, D.: Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology, J. Geophys. Res., 109, C12003, https://doi.org/10.1029/2004JC002378, 2004.
Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N. and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system, Q. J. Roy. Meteorol. Soc., 137, 553–597, https://doi.org/10.1002/qj.828, 2011.
Ekman, V. W.: On the influence of the earth's rotation on ocean currents, Ark. Mat. Astr. Fys., 11, 2, 1905.
Fecher, T., Pail, R., Gruber, T., and GOCO consortium: GOCO05c: A New Combined Gravity Field Model Based on Full Normal Equations and Regionally Varying Weighting, Surv. Geophys., 38, 571–590, https://doi.org/10.1007/s10712-016-9406-y, 2017.
Feng, H., Vandemark, D. C., Levin, J., and Wilkin, J.: Examining the Accuracy of GlobCurrent Upper Ocean Velocity Data Products on the Northwestern Atlantic Shelf, Remote Sens., 10, 1205, https://doi.org/10.3390/rs10081205, 2018.
Ferrari, R., Provost, C., Renault, A., Sennéchael, N., Barré, N., Park, Y.-H., and Lee, J.-H.: Circulation in Drake Passage revisited using new current time series and satellite altimetry: 1. The Yaghan Basin, J. Geophys. Res., 117, C12024, https://doi.org/10.1029/2012JC008264, 2012.
Ferrari, R., Provost, C., Renault, A., Barré, N., Sennéchael, N., Park, Y. H., and Lee, J.-H.: Circulation in Drake Passage revisited using new current time-series and satellite altimetry. Part II: The Ona Basin, J. Geophys. Res.-Oceans, 118, 147–165, https://doi.org/10.1029/2012JC008193, 2013.
Förste, C., Bruinsma, S. L., Abrikosov, O., Lemoine, J.-M., Marty, J. C., Flechtner, F., Balmino, G., Barthelmes, F., and Biancale, R.; EIGEN-6C4: The latest combined global gravity field model including GOCE data up to degree and order 2190 of GFZ Potsdam and GRGS Toulouse, GFZ Data Services, https://doi.org/10.5880/ICGEM.2015.1, 2014.
Gilardoni, M., Reguzzoni, M., and Sampietro, D.: GECO: a global gravity model by locally combining GOCE data and EGM2008; Stud. Geophys. Geodaet., 60, 228–247, https://doi.org/10.1007/s11200-015-1114-4, 2016.
Guinehut, S., Dhomps, A.-L., Larnicol, G., and Le Traon, P.-Y.: High resolution 3-D temperature and salinity fields derived from in situ and satellite observations, Ocean Sci., 8, 845–857, https://doi.org/10.5194/os-8-845-2012, 2012.
Hamon, M., Greiner, E., Le Traon, P.-Y., and Remy, E.: Impact of Multiple Altimeter Data and Mean Dynamic Topography in a Global Analysis and Forecasting System, J. Atmos. Ocean. Tech., 36, 1255–1266, https://doi.org/10.1175/JTECH-D-18-0236.1, 2019.
Knudsen, P., Andersen, O., and Maximenko, N.: A new ocean mean dynamic topography model, derived from a combination of gravity, altimetry and drifter velocity data, Adv. Space Res., ISSN 0273-1177, https://doi.org/10.1016/j.asr.2019.12.001, 2019a.
Knudsen, P., Andersen, O., Maximenko, N., and Hafner, J.: A new combined mean dynamic topography model – DTUUH19MDT, in: OSTST 2019, Chicago, 2019b.
Koenig, Z., Provost, C., Ferrari, R., Sennéchael, N., and Rio, M.-H.: Volume transport of the Antarctic Circumpolar Current: Production and validation of a 20 year long time series obtained from in situ and satellite observations, J. Geophys. Res.-Oceans, 119, 5407–5433, https://doi.org/10.1002/2014JC009966, 2014.
Lebedev, K. V., Yoshinari, H., Maximenko, N. A., and Hacker, P. W.: YoMaHa'07: Velocity data assessed from trajectories of Argo floats at parking level and at the sea surface, IPRC Tech. Note 4, available at: http://apdrc.soest.hawaii.edu/projects/yomaha/yomaha07/YoMaHa070612.pdf (last access: 1 June 2021), 12 June 2007.
Lee, J.-Y., Kang, D.-J., Kim, I.-N., Rho, T., Lee, T., Kang, C.-K., and Kim, K.-R.: Spatial and temporal variability in the pelagic ecosystem of the East Sea (Sea of Japan): A review, J. Mar. Syst., 78, 288–300, https://doi.org/10.1016/j.jmarsys.2009.02.013, 2009.
Levin, J., Wilkin, J., Fleming, N., and Zavala-Garay, J.: Mean circulation of the Mid-Atlantic Bight from a climatological data assimilative model, Ocean Model., 128, 1–14, 2018.
Lumpkin, R., Grodsky, S. A., Centurioni, L., Rio, M. H., Carton, J. A., and Lee, D.: Removing Spurious Low-Frequency Variability in Drifter Velocities, J. Atmos. Ocean. Tech., 30, 353–360, https://doi.org/10.1175/JTECH-D-12-00139.1, 2013.
Mayer-Gürr, T., Pail, R., Gruber, T., Fecher, T., Rexer, M., Schuh, W.-D., Kusche, J., Brockmann, J.-M., Rieser, D., Zehentner, N., Kvas, A., Klinger, B., Baur, O., Höck, E., Krauss, S., and Jäggi, A.: The combined satellite gravity field model GOCO05s, presented at OSTST, Vienna, Austria, 2015.
Pegliasco, C., Chaigneau, A., Morrow, R., and Dumas, F.: Detection and tracking of mesoscale eddies in the Mediterranean Sea: A comparison between the Sea Level Anomaly and the Absolute Dynamic Topography fields, Adv. Space Res., https://doi.org/10.1016/j.asr.2020.03.039, in press, 2020.
Pollard, R. T., Rhines, P. B., and Thompson, R. O. R. Y.: The deepening of the wind-Mixed layer, Geophys. Fluid Dynam., 4, 381–404, https://doi.org/10.1080/03091927208236105, 1973.
Pujol, M.-I., Schaeffer, P., Faugère, Y., Raynal, M., Dibarboure, G., and Picot, N.: Gauging the improvement of recent mean sea surface models: A new approach for identifying and quantifying their errors, J. Geophys. Res.-Oceans, 123, 5889–5911, https://doi.org/10.1029/2017JC013503, 2018.
Ralph, E. A. and Niiler P. P.: Wind-driven currents in the tropical Pacific, J. Phys. Oceanogr., 29, 2121–2129, 1999.
Renault, A., Provost, C., Sennéchael, N., Barré, N., and Kartavtseff, A.: Two full-depth velocity sections in the Drake Passage in 2006 – Transport estimates, Deep-Sea Res. Pt. II, 58, 2572–2591, https://doi.org/10.1016/j.dsr2.2011.01.004, 2011.
Rio, M.-H.: Absolute Dynamic Topography from Altimetry: Status and Prospects in the upcoming GOCE Era, in: Oceanography from Space, edited by: Barale, V., Gower, J., and Alberotanza, L., Springer, Dordrecht, https://doi.org/10.1007/978-90-481-8681-5_10, 2010.
Rio, M.-H. and Hernandez, F.: A Mean Dynamic Topography computed over the world ocean from altimetry, in-situ measurements and a geoid model, J. Geophys. Res., 109, C12032, https://doi.org/10.1029/2003JC002226, 2004.
Rio, M. H., Guinehut, S., and Larnicol, G.: New CNES-CLS09 global mean dynamic topography computed from the combination of GRACE data, altimetry, and in situ measurements, J. Geophys. Res., 116, C07018, https://doi.org/10.1029/2010JC006505, 2011.
Rio, M.-H., Mulet, S., and Picot, N.: Beyond GOCE for the ocean circulation estimate: synergetic use of altimetry, gravimetry, and in situ data provides new insight into geostrophic and Ekman currents, Geophys. Res. Lett., 41, 8918–8925, https://doi.org/10.1002/2014GL061773, 2014a.
Rio, M.-H., Pascual, A., Poulain, P.-M., Menna, M., Barceló, B., and Tintoré, J.: Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data, Ocean Sci., 10, 731–744, https://doi.org/10.5194/os-10-731-2014, 2014b.
Siegismund, F.: A spectrally consistent globally defined geodetic mean dynamic ocean topography, J. Geophys. Res.-Oceans, 125, e2019JC016031, https://doi.org/10.1029/2019JC016031, 2020.
Strub, P. T., James, C., Montecino, V., Rutllant, J. A., and Blanco, J. L.: Ocean circulation along the southern Chile transition region (38∘–46∘ S): Mean, seasonal and interannual variability, with a focus on 2014–2016, Prog. Oceanogr., 172, 159–198, https://doi.org/10.1016/j.pocean.2019.01.004, 2019.
Szekely, T., Gourrion, J., Pouliquen, S., and Reverdin, G.: The CORA 5.2 dataset for global in situ temperature and salinity measurements: data description and validation, Ocean Sci., 15, 1601–1614, https://doi.org/10.5194/os-15-1601-2019, 2019.
Taburet, G., Sanchez-Roman, A., Ballarotta, M., Pujol, M.-I., Legeais, J.-F., Fournier, F., Faugere, Y., and Dibarboure, G.: DUACS DT2018: 25 years of reprocessed sea level altimetry products, Ocean Sci., 15, 1207–1224, https://doi.org/10.5194/os-15-1207-2019, 2019.
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.
Satellite altimetry has revolutionized ocean observation by allowing the sea level to be...