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| Registros recuperados: 110 | |
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| Stanev, Ev; Le Traon, Pierre-yves; Peneva, El. |
| TOPEX/Poseidon (TIP) altimeter data in the Black Sea are analyzed for almost 5 years in parallel with available hydrological and meteorological data with the aim of studying the water balance and the dependency of sea level oscillations on meteorological and hydrological forcing. This forcing induces seasonal variations of mean sea level with oscillations of similar to 10-15 cm. The consistency between satellite and tidal gauge data is demonstrated in several coastal locations, and a mean ascending trend of similar to 3 cm yr(-1) is found in the two data sets. The variability in all components of water balance, including the Bosphorus outflow calculated as the difference between the fresh water flux and the time rate of sea level change estimated from... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00079/19034/16616.pdf |
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| Schiller, Andreas; Bell, Mike; Brassington, Gary; Brasseur, Pierre; Barciela, Rosa; De Mey, Pierre; Dombrowsky, Eric; Gehlen, Marion; Hernandez, Fabrice; Kourafalou, Villy; Larnicol, Gilles; Le Traon, Pierre-yves; Martin, Matthew; Oke, Peter; Smith, Gregory C.; Smith, Neville; Tolman, Hendrik; Wilmer-becker, Kirsten. |
| The marine environment plays an increasingly important role in shaping economies and infrastructures, and touches upon many aspects of our lives, including food supplies, energy resources, national security and recreational activities. Global Ocean Data Assimilation Experiment (GODAE) and GODAE OceanView have provided platforms for international collaboration that significantly contribute to the scientific development and increasing uptake of ocean forecasting products by end users who address societal issues such as those listed above. Many scientific challenges and opportunities remain to be tackled in the ever-changing field of operational oceanography, from the observing system to modelling, data assimilation and product dissemination. This paper... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00284/39522/38015.pdf |
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| Hernandez, Francisco; Le Traon, Pierre-yves; Morrow, R. |
| The SEMAPHORE mesoscale air/sea experiment was conducted in the Azores-Madeira region from July to November 1993. TOPEX/POSEIDON (T/P) and ERS 1 were flying simultaneously at that time. The main purposes of this paper are to evaluate the estimation of the oceanic mesoscale circulation from the two different sets of altimetric data (T/P and ERS 1) and to compare the results with in situ measurements provided by the SEMAPHORE hydrographic surveys and surface drifters (three expendable bathytermograph conductivity-temperature-depth surveys in a 500-km(2) box and a set of 47 Lagrangian surface drifters drogued at 150 m). Comparisons are carried out through the maps obtained by objective analysis from the four data sets. The mapping accuracy of T/P, ERS 1, T/P... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00079/18978/16624.pdf |
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| Maze, Guillaume; Cabanes, Cecile; Carval, Thierry; Coatanoan, Christine; D'Ortenzio, Fabrizio; Kolodziejczyk, Nicolas; Lebreton, Nathanaele; Le Traon, Pierre-yves; Poffa, Noe; Pouliquen, Sylvie; Thierry, Virginie. |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00318/42967/42474.pdf |
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| Von Schuckmann, Karina; Sallee, Jean-baptiste; Chambers, D.; Le Traon, Pierre-yves; Cabanes, Cecile; Gaillard, Fabienne; Speich, Sabrina; Hamon, Mathieu. |
| Variations in the world's ocean heat storage and its associated volume changes are a key factor to gauge global warming and to assess the earth's energy and sea level budget. Estimating global ocean heat content (GOHC) and global steric sea level (GSSL) with temperature/salinity data from the Argo network reveals a positive change of 0.5 +/- 0.1 W m(-2) (applied to the surface area of the ocean) and 0.5 +/- 0.1 mm year(-1) during the years 2005 to 2012, averaged between 60 degrees S and 60 degrees N and the 10-1500m depth layer. In this study, we present an intercomparison of three global ocean observing systems: the Argo network, satellite gravimetry from GRACE and satellite altimetry. Their consistency is investigated from an Argo perspective at global... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00202/31365/29753.pdf |
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| Pascual, Ananda; Faugere, Yannice; Larnicol, Gilles; Le Traon, Pierre-yves. |
| Data from four satellite altimeters are combined with the aim of improving the representation of the mesoscale variability in the Global Ocean. All missions [Jason-1, ERS-2/ENVISAT, Topex/Poseidon interleaved with Jason-1 and Geosat Follow-On] are cross-calibrated previously to produce weekly gridded maps. In areas of intense variability, the rms differences between a classical configuration of two altimeters and the scenario merging four missions can reach 10 cm and 400 cm(2)/s(2) in SLA and EKE, respectively, which represents an important percentage of the signal variance. A comparison with surface drifters shows that the four altimeter scenario improves the recovery of mesoscale structures that were not properly sampled with Jason(-1) + ERS-2/ENVISAT.... |
| Tipo: Text |
Palavras-chave: Satellite altimeters; Mesoscale variability; Global ocean. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1038.pdf |
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| Le Traon, Pierre-yves; Rouquet, Mc; Boissier, C. |
| Two years of Geosat data were used to systematically investigate the mesoscale variability and spatial scales of the North Atlantic. We first calculated sea surface height variability and eddy kinetic energy. These compare well with the eddy kinetic energy obtained with surface drifters. Then the spatial scales of mesoscale variability were characterized in 10° (latitude) × 10° (longitude) areas by their wave number spectra and autocorrelation functions. Comparison with existing in situ data shows good agreement, and it is believed that the total error budget is globally below that of the oceanic signal. The wave number spectra show significant differences as a function of latitude and longitude, and these can be related to different types of forcing... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00078/18934/17062.pdf |
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| Le Traon, Pierre-yves; Mercier, Herle. |
| The non-linear inverse model described in Mercier et al. (1992) is used to estimate the mean surface topography of the North Atlantic and its formal error. The surface is based on a large hydrographic and Lagrangian data set and has spatial resolution of 2-degrees in latitude by 2.5-degrees in longitude. The formal error is between 4 and 8 cm. Contrary to previous estimations, this takes into account the errors with regard both to the density field and to the estimation of the velocity field at a reference level. |
| Tipo: Text |
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| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00079/18977/17955.pdf |
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| Ducet, N; Le Traon, Pierre-yves. |
| Analyses of surface eddy kinetic energy (EYE) inferred from 5 years of merged TOPEX/Poseidon and ERS-1/2 altimetric data are presented in the Gulf Stream (GS) and the Kuroshio (KS) Current systems, focusing on anisotropy and EKE seasonal, interannual, and long-term variations, as well as Reynolds stresses. For both GS and KS a descriptive analysis of the EKE field shows that it is anisotropic along the path of the currents and assesses the close relationship between the spatial distribution of EKE high levels and bottom topography. A striking ocean feature is found in the GS, shaped as a zonal "double-blade" structure in the EKE field, centered at 37 degrees N, 71.5 degrees W, that likely corresponds to a regular and permanent lateral displacement of the... |
| Tipo: Text |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00084/19476/17095.pdf |
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| Maze, Guillaume; Cabanes, Cecile; Coatanoan, Christine; D'Ortenzio, Fabrizio; Lebreton, Nathanaele; Le Reste, Serge; Le Traon, Pierre-yves; Mamaca, Emina; Pouliquen, Sylvie; Thierry-theetten, Virginie. |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00180/29100/27514.pdf |
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| Le Traon, Pierre-yves; Gauzelin, P. |
| The response of the Mediterranean mean sea level to atmospheric pressure forcing is analyzed using 3 years of TOPEX/POSEIDON data. Coherence analysis between mean sea level and atmospheric pressure shows a significant departure from a standard inverse barometer effect at frequencies higher than 30 days(-1). At high frequencies the phase difference between sea level and pressure is about 100 degrees, while it should be 180 degrees for a perfect inverse barometer response. This result is in agreement with previous findings and confirms the role of the Straits of Gibraltar and Sicily in limiting the water exchange (and thus the response to atmospheric pressure forcing) at high frequencies. The response of the Mediterranean mean sea level is then investigated... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00079/19024/16607.pdf |
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| Ninove, Floriane; Le Traon, Pierre-yves; Remy, E.; Guinehut, S.. |
| Argo observations from 2005 to 2013 are used to characterize spatial scales of temperature and salinity variations from the surface down to 1300 m. Simulations are first performed to analyze the sensitivity of results to Argo sampling; they show that several years of Argo observations are required to estimate spatial scales of ocean variability over 20 degrees x 20 degrees boxes. Spatial scales are then computed over several large-scale areas. Zonal and meridional spatial scales (L-x and L-y which are zero crossing of covariance functions) vary as expected with latitudes. Scales are of about 100 km at high latitudes and more of 700 km in the Indian and Pacific equatorial-tropical regions. Zonal and meridional scales are similar except in... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00317/42845/42257.pdf |
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| Maze, Guillaume; Cabanes, Cécile; Carval, Thierry; Coatanoan, Christine; D'Ortenzio, Fabrizio; Lebreton, Nathanaelle; Le Reste, Serge; Le Traon, Pierre-yves; Pouliquen, Sylvie; Thierry, Virginie. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00254/36504/35050.pdf |
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| Pujol, M-i; Dibarboure, G.; Le Traon, Pierre-yves; Klein, Patrice. |
| An Ocean System Simulation Experiment is used to quantify the observing capability of the Surface Water and Ocean Topography (SWOT) mission and its contribution to higher-quality reconstructed sea level anomaly (SLA) fields using optimal interpolation. The paper focuses on the potential of SWOT for mesoscale observation (wavelengths larger than 100 km and time periods larger than 10 days) and its ability to replace or complement altimetry for classical mesoscale applications. For mesoscale variability, the wide swath from SWOT provides an unprecedented sampling capability. SWOT alone would enable the regional surface signal reconstruction as precisely as a four-altimeter constellation would, in regions where temporal sampling is optimum. For some specifics... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00101/21192/18818.pdf |
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| Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Le Traon, Pierre-yves. |
| A method to estimate mass and heat transports across hydrographic sections using hydrography together with altimetry data in a geostrophic box inverse model is presented. Absolute surface velocities computed from AVISO altimetry products made up of a combination of sea surface height measurements and geoid estimate are first compared to Ship Acoustic Doppler Current Profiler (S-ADCP) measurements of the Ovide project along hydrographic sections repeated every 2 years in summer from Portugal to Greenland. The rms difference between S-ADCP and altimetry velocities averaged on distances of about a hundred km accounts to 3.3 cm s−1. Considering that the uncertainty of S-ADCP velocities is found at 1.5 cm s−1, altimetry errors are estimated at 3 cm s−1.... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00038/14921/13751.pdf |
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| Roemmich, Dean; Belbéoc, Mathieu; Freeland, Howard; Garzoli, Sylvia; Gould, John; Grant, Fiona; Ignaszewski, Mark; King, Brian; Klein, Birgit; Le Traon, Pierre-yves; Mork, Kjell Arne; Brechner Owens, W; Pouliquen, Sylvie; Ravichandran, Muthalagu; Riser, Stephen; Sterl, Andreas; Suga, Toshio; Suk, Moon-sik; Sutton, Philip; Thierry, Virginie. |
| The Global Ocean Data Assimilation Experiment (GODAE [http://www.godae.org]) has spanned a decade of rapid technological development. The ever-increasing volume and diversity of oceanographic data produced by in situ instruments, remote-sensing platforms, and computer simulations have driven the development of a number of innovative technologies that are essential for connecting scientists with the data that they need. This paper gives an overview of the technologies that have been developed and applied in the course of GODAE, which now provides users of oceanographic data with the capability to discover, evaluate, visualize, download, and analyze data from all over the world. The key to this capability is the ability to reduce the inherent complexity of... |
| Tipo: Text |
Palavras-chave: GODAE; Argo; Global ocean observing system; Ocean data assimilation. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00059/17003/14505.pdf |
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| Morrow, Rosemary; Le Traon, Pierre-yves. |
| The paper provides a review of recent results on mesoscale ocean dynamics derived from satellite altimetry. Since 1992, we have had an unprecedented 18 year high-resolution monitoring of the ocean mesoscale field. Altimetry is often used in mesoscale studies in synergy with other remote sensing techniques and in situ data. This global, high-resolution data set has allowed oceanographers to quantify the previously unknown seasonal and interannual variations in eddy kinetic energy and eddy heat and salt transports, and investigate their causes. Eddy tracking techniques have allowed us to monitor their propagation pathways, to bring to light the meridional divergence of cyclones and anticyclones, and to question the role of Rossby waves versus non-linear... |
| Tipo: Text |
Palavras-chave: Satellite altimetry; Mesoscale eddies; Ocean circulation. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19847/17767.pdf |
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| Morrow, Rosemary; Fu, Lee-lueng; Ardhuin, Fabrice; Benkiran, Mounir; Chapron, Bertrand; Cosme, Emmanuel; D’ovidio, Francesco; Farrar, J. Thomas; Gille, Sarah T.; Lapeyre, Guillaume; Le Traon, Pierre-yves; Pascual, Ananda; Ponte, Aurelien; Qiu, Bo; Rascle, Nicolas; Ubelmann, Clement; Wang, Jinbo; Zaron, Edward D.. |
| The future international Surface Water and Ocean Topography (SWOT) Mission, planned for launch in 2021, will make high-resolution 2D observations of sea-surface height using SAR radar interferometric techniques. SWOT will map the global and coastal oceans up to 77.6∘ latitude every 21 days over a swath of 120 km (20 km nadir gap). Today’s 2D mapped altimeter data can resolve ocean scales of 150 km wavelength whereas the SWOT measurement will extend our 2D observations down to 15–30 km, depending on sea state. SWOT will offer new opportunities to observe the oceanic dynamic processes at scales that are important in the generation and dissipation of kinetic energy in the ocean, and that facilitate the exchange of energy between the ocean interior and the... |
| Tipo: Text |
Palavras-chave: Ocean mesoscale circulation; Satellite altimetry; SAR-interferometry; Tides and internal tides; Calibration-validation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00495/60685/64181.pdf |
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| Gaspar, P; Ogor, Florian; Le Traon, Pierre-yves; Zanife, Oz. |
| TOPEX (Ku band) and POSEIDON altimeter measurements at crossover points are used to estimate the sea state bias (SSB) of these two instruments. Different SSB models are tested, ranging from a constant fraction of the significant wave height (SWH) to more elaborate models involving up to four adjustable parameters. For TOPEX, the data show a decrease in the magnitude of the relative bias (SSB/SWH) with SWH. This behavior is well reproduced using a simple empirical model with two adjustable parameters. The three-parameter SSB model used in the NASA geophysical data records does well in explaining the wind-induced variations of the bias. A model including four adjustable parameters is needed to account for both the wind- and SWH-related variability of the... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00079/18984/16628.pdf |
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| Registros recuperados: 110 | |
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