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| Rubio, Anna; Mader, Julien; Corgnati, Lorenzo; Mantovani, Carlo; Griffa, Annalisa; Novellino, Antonio; Quentin, Céline; Wyatt, Lucy; Schulz-stellenfleth, Johannes; Horstmann, Jochen; Lorente, Pablo; Zambianchi, Enrico; Hartnett, Michael; Fernandes, Carlos; Zervakis, Vassilis; Gorringe, Patrick; Melet, Angélique; Puillat, Ingrid. |
| High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A... |
| Tipo: Text |
Palavras-chave: High frequency radar; Operational oceanography; Coastal observing systems; Radar remote sensing; Surface currents; Surface waves; Model assessment; Data assimilation. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00368/47879/47895.pdf |
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| Wergeland, Morten; Kudryavtsev, Vladimir; Chapron, Bertrand; Brekke, Camilla; Johannessen, Johnny A.. |
| Radarsat-2 C-band quad-polarization SAR observations of crude oil, emulsion, and plant oil slicks acquired in the wind speed range from 4 to 8 m/s and incidence angles from 30 degrees to 50 degrees are analyzed to yield new insights into the attenuation of short waves and breaking waves by surface slicks in real conditions. To provide a direct quantitative assessment of the surface wave damping, the measurements are decomposed into polarization difference (PD), polarization ratio (PR), nonpolarized (NP), and cross-polarized (CP) components. The PD signals relate to the extent of Bragg damping in the slick areas, over which the PR is systematically higher than over the ambient sea surface. Attenuation of the breaking waves is revealed to affect both the CP... |
| Tipo: Text |
Palavras-chave: Oil pollution; Radar imaging; Sea surface; Surface waves. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00363/47460/47484.pdf |
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| Deen, M.; Wielandt, E.; Stutzmann, Eleonore; Crawford, W.; Barruol, G.; Sigloch, K.. |
| The Earth's hum is the permanent free oscillations of the Earth recorded in the absence of earthquakes, at periods above 30 seconds. We present the first observations of its fundamental spheroidal eigenmodes on broadband Ocean Bottom Seismometers (OBS) in the Indian Ocean. At the ocean bottom, the effects of ocean infragravity waves (compliance) and seafloor currents (tilt) overshadow the hum. In our experiment, data are also affected by electronic glitches. We remove these signals from the seismic trace by subtracting average glitch signals; performing a linear regression and using frequency-dependent response functions between pressure, horizontal and vertical seismic components. This reduces the long period noise on the OBS to the level of a good land... |
| Tipo: Text |
Palavras-chave: Hum; Noise; Continuous oscillations; Broadband ocean bottom seismology; Surface waves; Glitch. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00407/51841/52446.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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| Dufois, Francois; Lowe, Ryan J.; Rayson, Matthew D.; Branson, Paul M.. |
| Owing to their strong forcing of the ocean surface, tropical cyclones strongly modify the hydrodynamics of Australia's North West Shelf (one of the world's tropical cyclone hotspots), which in turn plays a dominant role in its sediment dynamics. Previous modeling studies have focused on describing the short term sediment dynamics during individual tropical cyclones, but have lacked validation of the responses using field observations. As a consequence, the long term cumulative impact of the tropical cyclones on the residual sediment transport pathways at the shelf scale remains unclear. In this study we apply a sediment transport model over the North West Shelf, validate its performance using an extensive field dataset, and implement a 14 year‐long model... |
| Tipo: Text |
Palavras-chave: ROMS; COAWST; Sediment transport model; Tropical cyclone; Surface waves; Sediment pathways. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00449/56078/57601.pdf |
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| Said, Faozi; Johnsen, Harald; Nouguier, Frederic; Chapron, Bertrand; Engen, Geir. |
| The generalized curvature ocean surface scattering model [general curvature model (GCM)] is extended and revisited. Two key steps are addressed in this paper, namely, a necessary sea surface spectrum undressing procedure and the inclusion of a skewness phase-related component. Normalized radar cross-section (NRCS) simulations are generated at C-band for various wind conditions, polarizations, and incidence angles. Results are compared with CMOD5.n. Although the sea surface spectrum undressing procedure is a necessary step, the overall NRCS dynamic is notably affected only in low wind conditions (<= 5 m/s). The inclusion of the skewness phase-related component makes the most impact to the NRCS dynamic where the upwind/downwind asymmetry is clearly... |
| Tipo: Text |
Palavras-chave: Geophysical measurements; Radar cross section; Remote sensing; Sea surface; Surface waves. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00409/52013/52725.pdf |
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| Villas Bôas, Ana B.; Ardhuin, Fabrice; Ayet, Alex; Bourassa, Mark A.; Brandt, Peter; Chapron, Bertrand; Cornuelle, Bruce D.; Farrar, J. T.; Fewings, Melanie R.; Fox-kemper, Baylor; Gille, Sarah T.; Gommenginger, Christine; Heimbach, Patrick; Hell, Momme C.; Li, Qing; Mazloff, Matthew R.; Merrifield, Sophia T.; Mouche, Alexis; Rio,; Rodriguez, Ernesto; Shutler, Jamie D.; Subramanian, Aneesh C.; Terrill, Eric J.; Tsamados, Michel; Ubelmann, Clement; Van Sebille, Erik. |
| Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it... |
| Tipo: Text |
Palavras-chave: Air-sea interactions; Doppler oceanography from space; Surface waves; Absolute surface velocity; Ocean surface winds. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00509/62083/66271.pdf |
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