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| Schlembach, Florian; Passaro, Marcello; Quartly, Graham D.; Kurekin, Andrey; Nencioli, Francesco; Dodet, Guillaume; Piollé, Jean-francois; Ardhuin, Fabrice; Bidlot, Jean; Schwatke, Christian; Seitz, Florian; Cipollini, Paolo; Donlon, Craig. |
| Radar altimeters have been measuring ocean significant wave height for more than three decades, with their data used to record the severity of storms, the mixing of surface waters and the potential threats to offshore structures and low-lying land, and to improve operational wave forecasting. Understanding climate change and long-term planning for enhanced storm and flooding hazards are imposing more stringent requirements on the robustness, precision, and accuracy of the estimates than have hitherto been needed. Taking advantage of novel retracking algorithms, particularly developed for the coastal zone, the present work aims at establishing an objective baseline processing chain for wave height retrieval that can be adapted to all satellite missions. In... |
| Tipo: Text |
Palavras-chave: Satellite altimetry; LRM; Delay-Doppler; Altimetry; SAR altimetry; Significant wave height; Round robin; Assessment; Comparison; Retracking; ESA; Climate change initiative. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00630/74172/73742.pdf |
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| Ailliot, Pierre; Baxevani, Anastassia; Cuzol, Anne; Monbet, Valerie; Raillard, Nicolas. |
| The surface of the ocean, and so such quantities as the significant wave height, equation image, can be thought of as a random surface that develops over time. In this paper, we explore certain types of random fields in space and time, with and without dynamics that may or may not be driven by a physical law, as models for the significant wave height. Reanalysis data is used to estimate the sea-state motion which is modeled as a hidden Markov chain in a state space framework by means of an AR(1) process or in the presence of the dispersion relation. Parametric covariance models with and without dynamics are fitted to reanalysis and satellite data and compared to the empirical covariance functions. The derived models have been validated against satellite... |
| Tipo: Text |
Palavras-chave: Space-time model; Significant wave height; State-space models. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00363/47443/47472.pdf |
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| Wang, He; Zhu, Jianhua; Yang, Jingsong. |
| Nowadays, spaceborne Synthetic Aperture Radar (SAR) has become a powerful tool for providing significant wave height (SWH). Traditionally, validation of SAR derived SWH has been carried out against buoy measurements or model outputs, which only yield an inter-comparison, but not an "absolute" validation. In this study, the triple collocation error model has been introduced in the validation of Envisat ASAR derived SWH products. SWH retrievals from ASAR wave mode using ESA's algorithm are validated against in situ buoy data, and wave model hindcast results from WaveWatch III wave model, covering a period of six years. From the triple collocation validation analysis, the impacts of the collocation distance and water depth on the error of ASAR SWH are... |
| Tipo: Text |
Palavras-chave: Envisat ASAR; Significant wave height; Validation; Triple collocation. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00249/36019/34545.pdf |
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| Golubkin, Pavel A.; Chapron, Bertrand; Kudryavtsev, Vladimir N.. |
| Wind-generated waves in the Kara, Laptev, and East-Siberian Seas are investigated using altimeter data from Envisat RA-2 and SARAL-AltiKa. Only isolated ice-free zones had been selected for analysis. Wind seas can be treated as pure wind-generated waves without any contamination by ambient swell. Such zones were identified using ice concentration data from microwave radiometers. Altimeter data, both significant wave height (SWH) and wind speed, for these areas were further obtained for the period 2002-2012 using Envisat RA-2 measurements, and for 2013 using SARAL-AltiKa. Dependencies of dimensionless SWH and wavelength on dimensionless wave generation spatial scale are compared to known empirical dependencies for fetch-limited wind wave development. We... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Satellite altimeter; Significant wave height; Wind speed. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00302/41330/40642.pdf |
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| Hito Sepulveda, Hector; Queffeulou, Pierre; Ardhuin, Fabrice. |
| SARAL/AltiKa GDR-T are analyzed to assess the quality of the significant wave height (SWH) measurements. SARAL along-track SWH plots reveal cases of erroneous data, more or less isolated, not detected by the quality flags. The anomalies are often correlated with strong attenuation of the Ka-band backscatter coefficient, sensitive to clouds and rain. A quality test based on the 1Hz standard deviation is proposed to detect such anomalies. From buoy comparison, it is shown that SARAL SWH is more accurate than Jason-2, particularly at low SWH, and globally does not require any correction. Results are better with open ocean than with coastal buoys. The scatter and the number of outliers are much larger for coastal buoys. SARAL is then compared with Jason-2 and... |
| Tipo: Text |
Palavras-chave: Radar altimeter; Significant wave height; Satellite; SARAL; AltiKa; Validation. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00286/39675/38199.pdf |
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| Aoun, N. S.; Harajli, H. A.; Queffeulou, Pierre. |
| The present work is the first attempt to methodologically assess the wave power prospects off the coast of Lebanon. Working around 1.5 years of buoy data, measurements for the significant wave height and wave period were inputted to establish a joint frequency table that was related to power matrixes of three selected wave energy converters. The spatial and temporal representability of the analysis was extended through assessing altimeter data of H-s over 20 years and for three points off the coast of Lebanon; southern Lebanon, buoy location off the coast of Beirut, and northern Lebanon. The altimeter data indicated that H-s values as measured through the buoy is within 1 standard deviation of the offshore regional mean, however adopting the regional mean... |
| Tipo: Text |
Palavras-chave: Wave energy converter; Lebanon; Significant wave height; Wave period; Mediterranean sea. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28763/27296.pdf |
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