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| Registros recuperados: 12 | |
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| Hong-Joo,Yoon; Yeong-Seup,Kim; Byong-Hyuk,Kwon. |
| Sea level variations and sea surface circulations in the Korean seas were observed by Topex/Poseidon altimeter data from 1993 through 1997. In sea level variations, the West and South Sea showed relatively high variations with comparison to the East Sea. Then, the northern and southern area in the West Sea showed the range of 20~30cm and 18~24cm, and the northern west of Jeju island and the southern west of Tsushima island in the South Sea showed the range of 15~20 cm and 10~15 cm, respectively. High variations in the West Sea was results to the inflow in sea surface of Yellow Sea Warm Current (YSWC) and bottom topography. Sea level variations in the South Sea was due to two branch currents (Jeju Warm Current and East Korea Warm Current) originated from... |
| Tipo: Journal article |
Palavras-chave: Sea level variations; Sea surface circulations; Altimeter. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000300051 |
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| Feng, H; Vandemark, D; Quilfen, Yves; Chapron, Bertrand; Beckley, B. |
| The study presents assessment of an operational wave model (Wavewatch III), focusing upon the model sensitivity to wind-forcing products. Four wind fields are used to drive the model, including the NCEP/NCAR reanalysis and three other products that assimilate various satellite wind measurements having high spatial resolution, including the QuikSCAT scatterometer. Three wave field statistics: significant wave height, mean zero-crossing wave period, and mean square slope are compared with collocated TOPEX altimeter derivatives to gauge the relative skill of differing wind-forced model runs, as well as to demonstrate an extended use of the altimeter beyond simply supplying wave height for wave model validation and assimilation. Results suggest that model... |
| Tipo: Text |
Palavras-chave: Sea state bias; Wind forcing; Scatterometer; Altimeter; Wave modeling. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1861.pdf |
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| Hu, Denghui; Xu, Yongsheng. |
| With the development of satellite observation technology, higher resolution and shorter return cycle have also placed higher demands on satellite data processing. The non-tide high-frequency barotropic oscillation in the marginal sea produces large aliasing errors in satellite altimeter observations. In previous studies, the satellite altimeter aliasing correction generally relied on a few bottom pressure data or the model data. Here, we employed the high-frequency tide gauge data to extract the altimeter non-tide aliasing correction in the west Mediterranean Sea. The spatial average method and EOF analysis method were adopted to track the high-frequency oscillation signals from 15 tide gauge records (TGs), and then were used to correct the aliasing errors... |
| Tipo: Text |
Palavras-chave: Tide gauge; EOF analysis; De-aliasing; Altimeter. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75262/75467.pdf |
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| Deloffre, J; Verney, Romaric; Lafite, R; Lesueur, P; Lesourd, S; Cundy, A. |
| The objective of this study is to propose an original approach to the analysis of the formation of intertidal rhythmites, their preservation, and the evaluation of sedimentation rates on estuarine mudflats. Three mudflats, one from each of three estuaries, were analysed using a combination of long-term (>a year), high-frequency (1 burst/10 or 20 min), and high-resolution (0.2 cm) altimeter datasets and X-ray images of sediment cores collected during topographic surveys. The results highlight the roles played by sediment supply, hydrodynamics, and morphology of the lower estuaries on the sedimentation rhythms. While the sediment-starved Medway estuary (Kent, UK) remains stable at different time-scales, the annual sedimentation rates on the sheltered... |
| Tipo: Text |
Palavras-chave: Macrotidal estuary; X ray imagery; Altimeter; Rhythmites; Mud; Morphology. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3517.pdf |
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| Chen, G; Chapron, Bertrand; Ezraty, Robert; Vandemark, D. |
| More than a dozen of wind speed (U) algorithms have been proposed during the past 2 decades, as a result of a continuing effort to improve altimeter wind measurement. The progress in terms of accuracy, however, is seen to be rather slow. The reported root mean square (RMS) error of prevailing algorithms varies mostly between 1.6 and 2.0 m/s for the dominant wind regime. As far as the TOPEX altimeter is concerned, three measured quantities, namely, the radar cross sections from Ku and C band (sigma(Ku) and sigma(C)), as well as the significant wave height (H-s), have been used in previous algorithm developments, resulting in a variety of single-, dual-, and three-parameter model functions. On the basis of the finding of a banded dependency of the... |
| Tipo: Text |
Palavras-chave: Sea surface wind speed; Retrieval; TOPEX; Altimeter; Dual frequency. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00000/10224/9579.pdf |
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| Vincent, Patrick; Steunou, N; Caubet, E; Phalippou, L; Rey, L; Thouvenot, E; Verron, J. |
| This paper describes the Ka-band altimetry payload and system that has been studied for several years by CNES, ALCATEL SPACE and some science laboratories. Altimetry is one of the major elements of the ocean observing system to be made sustainable through the GEOSS ( Global Earth Observation System of Systems) and GMES ( Global Monitoring of the Environment and Security) programs. A short review of some mission objectives to be fulfilled in terms of mesoscale oceanography in the frame of the GEOSS and GMES programs is performed. To answer the corresponding requirements, the approach consisting in a constellation of nadir altimeter is discussed. A coupled Ka-band altimeter-radiometer payload is then described; technical items are detailed to explain how... |
| Tipo: Text |
Palavras-chave: Altimeter; Radiometer; Ocean mesoscale circulation; Ka-band. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00284/39508/38003.pdf |
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| Ardhuin, Fabrice; Stopa, Justin; Chapron, Bertrand; Collard, Fabrice; Husson, Romain; Jensen, Robert E.; Johannessen, Johnny; Mouche, Alexis; Passaro, Marcello; Quartly, Graham D.; Swail, Val; Young, Ian. |
| Sea state information is needed for many applications, ranging from safety at sea and on the coast, for which real time data are essential, to planning and design needs for infrastructure that require long time series. The definition of the wave climate and its possible evolution requires high resolution data, and knowledge on possible drift in the observing system. Sea state is also an important climate variable that enters in air-sea fluxes parameterizations. Finally, sea state patterns can reveal the intensity of storms and associated climate patterns at large scales, and the intensity of currents at small scales. A synthesis of user requirements leads to requests for spatial resolution at kilometer scales, and estimations of trends of a few centimeters... |
| Tipo: Text |
Palavras-chave: Sea state; Waves; Altimeter; SAR; Swell; Remote sensing; Buoy; Microseisms. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00489/60090/63432.pdf |
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| Cheng, Yongcun; Tournadre, Jean; Li, Xiaofeng; Xu, Qing; Chapron, Bertrand. |
| Ocean surface films can damp short capillary-gravity waves, reduce the surface mean square slope, and induce “sigma0 blooms” in satellite altimeter data. No study has ascertained the effect of such film on altimeter measurements due to lack of film data. The availability of Environmental Response Management Application (ERMA) oil cover, daily oil spill extent and thickness data acquired during the Deepwater Horizon (DWH) oil spill accident provides a unique opportunity to evaluate the impact of surface film on altimeter data. In this study, the Jason-1/2 passes nearest to the DWH platform are analyzed to understand the waveform distortion caused by the spill as well as the variation of σ0 as a function of oil thickness, wind speed and radar band. Jason-1/2... |
| Tipo: Text |
Palavras-chave: Oil spill; Altimeter; Sigma0 bloom; Waveform. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00381/49203/49635.pdf |
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| Tran, Ngan; Chapron, Bertrand. |
| The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Ku- and C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at higher winds. These results extend, for the first time, recent theoretical improved scattering approximation, and point some similarities between scattering and emission mechanisms at nadir. The observed directional effect can thus be interpreted as a signature of the curvature anisotropy of wind-generated short-scale waves. Sensitivities to both wind speed and sea... |
| Tipo: Text |
Palavras-chave: Altimeter; Radar cross section; Polarization; Wind direction; Sea state. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00004/11557/8150.pdf |
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| Jiang, Haoyu; Stopa, Justin; Wang, He; Husson, Romain; Mouche, Alexis; Chapron, Bertrand; Chen, Ge. |
| A method for systematically tracking swells across oceanic basins is developed by taking advantage of high-quality data from space-borne altimeters and wave model output. The evolution of swells is observed over large distances based on 202 swell events with periods ranging from 12 to 18 s. An empirical attenuation rate of swell energy of about 4 × 10−7 m−1 is estimated using these observations, and the nonbreaking energy dissipation rates of swells far away from their generating areas are also estimated using a point source model. The resulting acceptance range of nonbreaking dissipation rates is −2.5 to 5.0 × 10−7 m−1, which corresponds to a dissipation e-folding scales of at least 2000 km for steep swells, to almost infinite for small-amplitude swells.... |
| Tipo: Text |
Palavras-chave: Altimeter; Swell dissipation; Swell tracking. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00314/42526/41897.pdf |
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| Hauser, Daniele; Tourain, Cedric; Hermozo, Laura; Alraddawi, D.; Aouf, L.; Chapron, Bertrand; Dalphinet, A.; Delaye, L.; Dalila, M.; Dormy, E.; Gouillon, F.; Gressani, Victor; Grouazel, Antoine; Guitton, Gilles; Husson, R.; Mironov, Alexey; Mouche, Alexis; Ollivier, A.; Oruba, L.; Piras, E.; Suquet, R. Rodriguez; Schippers, P.; Tison, C.; Tran, Ngan. |
| This article describes the first results obtained from the Surface Waves Investigation and Monitoring (SWIM) instrument carried by the China France Oceanography Satellite (CFOSAT), which was launched on October 29, 2018. SWIM is a Ku-band radar with a near-nadir scanning beam geometry. It was designed to measure the spectral properties of surface ocean waves. First, the good behavior of the instrument is illustrated. It is then shown that the nadir products (significant wave height, normalized radar cross section, and wind speed) exhibit an accuracy similar to standard altimeter missions, thanks to a new retracking algorithm, which compensates a lower sampling rate compared to standard altimetry missions. The off-nadir beam observations are analyzed in... |
| Tipo: Text |
Palavras-chave: Spaceborne radar; Radar cross-sections; Surface waves; Sea surface; Instruments; Altimeter; Ocean wave spectra; Radar measurements; Scatterometer; Sea surface; Spaceborne radar; Speckle noise. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78869/81168.pdf |
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| Registros recuperados: 12 | |
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