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| Mouche, Alexis; He, W.; Husson, R.; Guitton, Gilles; Chapron, Bertrand; Li, Huimin. |
| Sentinel-1 A now routinely acquires data over the ocean since 2014. Data are processed by ESA through the Payload Data Ground Segment up to Level-2 for Copernicus users. Level-2 products consist of geo-located geophysical parameters related to wind, waves and ocean current. In particular, Sentinel-1A wave measurements provide 2D ocean swell spectra (2D wave energy distribution as a function of wavelength and direction) as well as integrated parameters such as significant wave height, dominant wavelength and direction for each partition. In 2016, Sentinel-1 B will be launched by ESA and GF-3 by CNSA. Then in 2018, CFOSAT (China France Oceanography Satellite project), a joint mission from the Chinese and French Space Agencies, will be launched. They will... |
| Tipo: Text |
Palavras-chave: Ocean remote sensing; Synthetics aperture radar; Ocean wave-spectrometer; 2D ocean wave spectrum; Level-4. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00364/47469/47488.pdf |
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| Hauser, D.; Tison, C.; Amiot, T.; Delaye, L.; Mouche, Alexis; Guitton, Gilles; Aouf, L.; Castillan, P.. |
| CFOSAT (the China France Oceanography Satellite) is a joint mission from the Chinese and French Space Agencies, devoted to the observation ocean surface wind and waves so as to improve wind and wave forecast for marine meteorology, ocean dynamics modeling and prediction, climate variability knowledge, fundamental knowledge of surface processes. Currently under Phase D (manufacturing phase), the launch is now planned for mid-2018 the later. The CFOSAT will carry two payloads, both Ku-Band radar: the wave scatterometer (SWIM) and the wind scatterometer (SCAT). Both instruments are based on new concepts with respect to existing satellite-borne wind and wave sensors. Indeed, one of the originalities of CFOSAT is that it will provide simultaneously and in the... |
| Tipo: Text |
Palavras-chave: Satellite; Radar; Surface ocean waves; Surface ocean wind; Scatterometer; CFOSAT. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00363/47468/47487.pdf |
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| Ardhuin, Fabrice; Collard, Fabrice; Chapron, Bertrand; Ardhuin, Fanny; Guitton, Gilles; Mouche, Alexis; Stopa, Justin. |
| Swell evolution from the open ocean into sea ice is poorly understood, in particular the amplitude attenuation expected from scattering and dissipation. New synthetic aperture radar (SAR) data from Sentinel-1A wave mode reveal intriguing patterns of bright oscillating lines shaped like instant noodles. We investigate cases in which the oscillations are in the azimuth direction, around a straight line in the range direction. This observation is interpreted as the distortion by the SAR processing of crests from a first swell, due to the presence of a second swell. Since deviations from a straight line should be proportional to the orbital velocity toward the satellite, swell height can be estimated, from 1.5 to 5 m in the present case. The evolution of this... |
| Tipo: Text |
Palavras-chave: Ocean waves; SAR; Sea ice. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00256/36718/35332.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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| Mouche, Alexis; Collard, Fabrice; Chapron, Bertrand; Dagestad, Knut-frode; Guitton, Gilles; Johannessen, Johnny A.; Kerbaol, Vincent; Hansen, Morten Wergeland. |
| The synthetic aperture radar (SAR) Doppler centroid has been used to estimate the scatter line-of-sight radar velocity. In weak to moderate ocean surface current environment, the SAR Doppler centroid is dominated by the directionality and strength of wave-induced ocean surface displacements. In this paper, we show how this sea state signature can be used to improve surface wind retrieval from SAR. Doppler shifts of C-band radar return signals from the ocean are thoroughly investigated by colocating wind measurements from the ASCAT scatterometer with Doppler centroid anomalies retrieved from Envisat ASAR. An empirical geophysical model function (CDOP) is derived, predicting Doppler shifts at both VV and HH polarization as function of wind speed, radar... |
| Tipo: Text |
Palavras-chave: Doppler; Surface wind; Synthetic aperture radar (SAR). |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19896/17554.pdf |
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