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| Registros recuperados: 13 | |
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| Picoli,Michelle C. A.; Lamparelli,Rubens A. C.; Sano,Edson E.; Rocha,Jansle V.. |
| Some models have been developed using agrometeorological and remote sensing data to estimate agriculture production. However, it is expected that the use of SAR images can improve their performance. The main objective of this study was to estimate the sugarcane production using a multiple linear regression model which considers agronomic data and ALOS/PALSAR images obtained from 2007/08, 2008/09 and 2009/10 cropping seasons. The performance of models was evaluated by coefficient of determination, t-test, Willmott agreement index (d), random error and standard error. The model was able to explain 79%, 12% and 74% of the variation in the observed productions of the 2007/08, 2008/09 and 2009/10 cropping seasons, respectively. Performance of the model for the... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Synthetic aperture radar; L-band; Modeling; Remote sensing. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162014000600019 |
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| Mercier, Grégoire; Ardhuin, Fanny. |
| Spaceborne synthetic aperture radar (SAR) is well adapted to detect ocean pollution independently from daily or weather conditions. In fact, oil slicks have a specific impact on ocean wave spectra. Initial wave spectra may be characterized by three kinds of waves, namely big, medium, and small, which correspond physically to gravity and gravity-capillary waves. The increase of viscosity, due to the presence of oil damps gravity-capillary waves. This induces not only a damping of the backscattering to the sensor but also a damping of the energy of the wave spectra. Thus, local segmentation of wave spectra may be achieved by the segmentation of a multiscale decomposition of the original SAR image. In this paper, a semisupervised oil-slick detection is... |
| Tipo: Text |
Palavras-chave: Water pollution; Synthetic aperture radar; Sea surface; Satellite applications; Oil spill; Image analysis. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1948.pdf |
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| Huimin, Li. |
| Spaceborne synthetic aperture radar (SAR) has been demonstrated invaluable in observing the global ocean winds and waves. SAR images acquired by multiple sensors are employed, including Sentinel-1(S-1), Envisat/ASAR, Gaofen-3 and Radarsat-2. This thesis reviews the commonly used SAR parameters (NRCS and azimuth cutoff) in the first part. A series of calibration steps are required to obtain a proper NRCS and assessment of NRCS is carried out for S-1wave mode (WV). It turns out that WV is poorly calibrated and is thus re-calibrated to obtain accurate NRCS. Azimuth cut off is demonstrated to be complementary to NRCS and can account for the sea state impact on the wind retrieval. Based on the available fully polarimetric SAR products, azimuth cut off is found... |
| Tipo: Text |
Palavras-chave: Radar à synthèse d'ouverture; Vents et vagues océaniques; Synthetic aperture radar; Ocean winds; Ocean waves. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00504/61575/65505.pdf |
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| Wang, Chen; Mouche, Alexis; Tandeo, Pierre; Stopa, Justin; Longépé, Nicolas; Erhard, Guillaume; Foster, Ralph C.; Vandemark, Douglas; Chapron, Bertrand. |
| The Sentinel‐1 mission is part of the European Copernicus program aiming at providing observations for Land, Marine and Atmosphere Monitoring, Emergency Management, Security and Climate Change. It is a constellation of two (Sentinel‐1 A and B) Synthetic Aperture Radar (SAR) satellites. The SAR wave mode (WV) routinely collects high‐resolution SAR images of the ocean surface during day and night and through clouds. In this study, a subset of more than 37,000 SAR images is labelled corresponding to ten geophysical phenomena, including both oceanic and meteorologic features. These images cover the entire open ocean and are manually selected from Sentinel‐1A WV acquisitions in 2016. For each image, only one prevalent geophysical phenomenon with its prescribed... |
| Tipo: Text |
Palavras-chave: Manual labelling; Ocean surface phenomena; Sentinel-1 wave mode; Synthetic aperture radar. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62406/66659.pdf |
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| Wang, He; Mouche, Alexis; Husson, Romain; Chapron, Bertrand. |
| Synthetic Aperture Radar (SAR) in wave mode is a powerful sensor for monitoring the swells propagating across ocean basins. Here, we investigate crossing swells in the Indian Ocean using 10-years Envisat SAR wave mode archive spanning from December 2003 to April 2012. Taking the benefit of the unique "fireworks" analysis on SAR observations, we reconstruct the origins and propagating routes that are associated with crossing swell pools in the Indian Ocean. Besides, three different crossing swell mechanisms are discriminated from space by the comparative analysis between results from "fireworks" and original SAR data: (1) in the mid-ocean basin of the Indian Ocean, two remote southern swells form the crossing swell; (2) wave-current interaction; and, (3)... |
| Tipo: Text |
Palavras-chave: Crossing swells; Synthetic aperture radar; Wave mode; Fireworks analysis; Indian Ocean. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00679/79110/81601.pdf |
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| Collard, Fabrice; Ardhuin, Fabrice; Chapron, Bertrand. |
| Wave spectra derived from synthetic aperture radar (SAR) images acquired by ENVISATs are compared to in situ measurements by seven sensors, deployed in a field experiment carried out on the French coast of La Manche (English Channel). The wave spectra inversion scheme is adapted for shallow water from the European Space Agency (ESA)'s operational processing techniques used for level 2 ocean wave products. Under the low to moderate wind speed observed conditions, overall good agreement is found between in situ and SAR observations over a wide range of wave heights and directions, including waves propagating in the radar azimuth direction and incidence angles different from the standard imagette products. |
| Tipo: Text |
Palavras-chave: Synthetic aperture radar; Ocean waves. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1109.pdf |
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| Jiang, Haoyu; Mouche, Alexis; Wang, He; Babanin, Alexander V.; Chapron, Bertrand; Chen, Ge. |
| Numerical wave models are powerful tools for investigating global wave climate. Here a global wave hindcast is employed to estimate the global pattern of crossing swells. However, the global patterns of crossing swells derived from the model are different from those derived from the synthetic aperture radar (SAR) wave mode products of quasi-linear inversion, indicating one of them is questionable. The comparison shows that the first two most energetic swells inversed by SAR are often not in accordance with the first two most energetic swells in the model, and this will have a large impact on the statistics of the data. Before this problem is solved, SAR wave products of quasi-linear inversion should be treated with care in wave climate studies. |
| Tipo: Text |
Palavras-chave: Synthetic aperture radar; Quasi-linear inversion; Crossing swells; Wave climate. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00369/47979/48003.pdf |
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| Fan, Shengren; Zhang, Biao; Mouche, Alexis; Perrie, William; Zhang, Jun A.; Zhang, Guosheng. |
| Under extreme weather conditions, the imprints of kilometer-scale marine atmospheric boundary layer roll vortices on the ocean surface are clearly visible in synthetic aperture radar (SAR) images of storms. Therefore, information about wind direction in storms can be obtained by analyzing SAR image features caused by boundary layer rolls. VH-polarized SAR imagery captures the structural features of storms well and shows prominent image gradients along the radial directions of the storm. The signal-to-noise ratios of VH-polarized images are small in low wind speed areas, but they are large in the same regions of VV-polarized images. Also, the capability of retrieving the atmospheric rolls orientation in VV-polarization is found to be sensitive to incidence... |
| Tipo: Text |
Palavras-chave: Synthetic aperture radar; Radar polarimetry; Wind speed; Atmospheric modeling; Spaceborne radar; Radar measurements; Synthetic aperture radar (SAR); Tropical cyclone (TC); Wind direction. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72143/70953.pdf |
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| Sapp, Joseph W.; Mouche, Alexis; Jelenak, Zorana; Chang, Paul S.; Frasier, Stephen J.. |
| In Winter 2017, the University of Massachusetts Amherst's Imaging Wind and Rain Airborne Profiler (IWRAP) was flown on a National Oceanic and Atmospheric Administration (NOAA) WP-3D Hurricane Hunter aircraft under the direction of scientists from Center for Satellite Applications and Research (STAR) at NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) over the North Atlantic ocean out of Shannon, Ireland. IWRAP is a dual-frequency, conically scanning, profiling Doppler radar initially developed by Microwave Remote Sensing Laboratory (MIRSL) at the University of Massachusetts Amherst that is routinely installed on the NOAA WP-3D research aircraft. The flight on February 6, 2017, targeted a region of high winds (greater than 30... |
| Tipo: Text |
Palavras-chave: Satellites; Aircraft; Spaceborne radar; Synthetic aperture radar; Sea measurements; Wind speed; C-band; Cross polarization; Normalized radar cross section (NRCS); Ocean winds; Scatterometry. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00640/75251/75648.pdf |
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| Registros recuperados: 13 | |
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