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2D ocean waves spectra from space: a challenge for validation and synergetic use ArchiMer
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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CFOSAT: A new Chinese-French satellite for joint observations of ocean wind vector and directional spectra of ocean waves ArchiMer
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: http://archimer.ifremer.fr/doc/00363/47468/47487.pdf
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Estimates of ocean wave heights and attenuation in sea ice using the SAR wave mode on Sentinel-1A ArchiMer
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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On the Use of Doppler Shift for Sea Surface Wind Retrieval From SAR ArchiMer
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
Registros recuperados: 4
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