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Registros recuperados: 9
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Developing European operational oceanography for Blue Growth, climate change adaptation and mitigation, and ecosystem-based management ArchiMer
She, Jun; Allen, Icarus; Buch, Erik; Crise, Alessandro; Johannessen, Johnny A.; Le Traon, Pierre-yves; Lips, Urmas; Nolan, Glenn; Pinardi, Nadia; Reissmann, Jan H.; Siddorn, John; Stanev, Emil; Wehde, Henning.
Operational approaches have been more and more widely developed and used for providing marine data and information services for different socio-economic sectors of the Blue Growth and to advance knowledge about the marine environment. The objective of operational oceanographic research is to develop and improve the efficiency, timeliness, robustness and product quality of this approach. This white paper aims to address key scientific challenges and research priorities for the development of operational oceanography in Europe for the next 5-10 years. Knowledge gaps and deficiencies are identified in relation to common scientific challenges in four EuroGOOS knowledge areas: European Ocean Observations, Modelling and Forecasting Technology, Coastal...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00353/46430/46143.pdf
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Imaging mesoscale upper ocean dynamics using synthetic aperture radar and optical data ArchiMer
Kudryavtsev, Vladimir; Myasoedov, Alexander; Chapron, Bertrand; Johannessen, Johnny A.; Collard, Fabrice.
A synergetic approach for quantitative analysis of high-resolution ocean synthetic aperture radar (SAR) and imaging spectrometer data, including the infrared (IR) channels, is suggested. This approach first clearly demonstrates that sea surface roughness anomalies derived from Sun glitter imagery compare very well to SAR roughness anomalies. As further revealed using these fine-resolution (similar to 1 km) observations, the derived roughness anomaly fields are spatially correlated with sharp gradients of the sea surface temperature (SST) field. To quantitatively interpret SAR and optical (in visible and IR ranges) images, equations are derived to relate the "surface roughness" signatures to the upper ocean flow characteristics. As developed, a direct link...
Tipo: Text
Ano: 2012 URL: https://archimer.ifremer.fr/doc/00079/18999/16570.pdf
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Joint sun-glitter and radar imagery of surface slicks ArchiMer
Kudryavtsev, Vladimir; Myasoedov, Alexander; Chapron, Bertrand; Johannessen, Johnny A.; Collard, Fabrice.
A method is proposed to retrieve and interpret fine spatial variations of the sea surface roughness in sun glitter imagery. Observed sun glitter brightness anomalies are converted using a transfer function determined from the smoothed shape of sun glitter brightness. The method is applied to MODIS and MERIS sun glitter imagery of natural oil seeps and the catastrophic Deepwater Horizon oil spill in the Gulf of Mexico. The short-scale roughness variations in the presence of mineral oils slicks are consistently extracted and compared to variations associated with the biogenic slicks. In doing so, the wind speed dependency on the roughness anomalies is also considered. A comparison to normalized radar cross section (NRCS) anomalies taken from the...
Tipo: Text Palavras-chave: Sun-glitter; Mean square slope; Surface slicks; Oil spills; SAR imaging model; SAR and optical synergy.
Ano: 2012 URL: https://archimer.ifremer.fr/doc/00083/19439/17217.pdf
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Ocean remote sensing data integration - examples and outlook ArchiMer
Chapron, Bertrand; Bingham, A; Collard, Fabrice; Donlon, Craig; Johannessen, Johnny A.; Piolle, Jean-francois; Reul, Nicolas.
Satellite remote sensing has emerged as an essential and necessary observing system to acquire global information about the state of the ocean. Complemented with in situ observing networks, the ultimate goals are to be able to make accurate estimates of selected key sets of geophysical variables, with the intention of either making operational predictions across time and spatial boundaries, or advancing fundamental knowledge through development of empirical relationships and theoretical models. For satellite oceanography, improvements are then constantly being sought in our understandings of the geophysical processes, the sensor physics, the electromagnetic and microwave properties and interactions at the complex air-sea interface. Challenges appear as...
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Ano: 2010 URL: http://archimer.ifremer.fr/doc/00029/14046/11241.pdf
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On Dual Co-Polarized SAR Measurements of the Ocean Surface ArchiMer
Kudryavtsev, Vladimir N.; Chapron, Bertrand; Myasoedov, Alexander G.; Collard, Fabrice; Johannessen, Johnny A..
An effective methodology using satellite high-resolution polarized information to interpret and quantitatively assess various surface ocean phenomena is suggested. Using a sample RADARSAT-2 quad-polarization ocean synthetic aperture radar (SAR) scene, the dual co-polarization (VV and HH) radar data are combined into polarization difference, polarization ratio, and nonpolarized components. As demonstrated, these field quantities provide means to distinguish Bragg scattering mechanism and radar returns from breaking waves. As shown, quantitative characteristics of the surface manifestation of ocean currents, slicks, and wind field features in these dual co-polarization properties are very different and may be effectively used in the development of new SAR...
Tipo: Text Palavras-chave: Radar cross sections; Radar signal analysis; Synthetic aperture radar (SAR) imaging.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00149/26042/24890.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
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Progress in satellite remote sensing for studying physical processes at the ocean surface and its borders with the atmosphere and sea ice ArchiMer
Shutler, Jamie D.; Quartly, Graham D.; Donlon, Craig J.; Sathyendranath, Shubha; Platt, Trevor; Chapron, Bertrand; Johannessen, Johnny A.; Girard-ardhuin, Fanny; Nightingale, Philip D.; Woolf, David K.; Hoyer, Jacob L..
Physical oceanography is the study of physical conditions, processes and variables within the ocean, including temperature-salinity distributions, mixing of the water column, waves, tides, currents and air-sea interaction processes. Here we provide a critical review of how satellite sensors are being used to study physical oceanography processes at the ocean surface and its borders with the atmosphere and sea ice. The paper begins by describing the main sensor types that are used to observe the oceans (visible, thermal infrared and microwave) and the specific observations that each of these sensor types can provide. We then present a critical review of how these sensors and observations are being used to study: (i) ocean surface currents, (ii) storm...
Tipo: Text Palavras-chave: Atmosphere-ocean interface; Sea ice; Remote sensing; Surface currents; Storm surge; Surface heat fluxes; Atmosphere-ocean gas fluxes; Oceanography.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00333/44405/44318.pdf
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SEASTAR: A Mission to Study Ocean Submesoscale Dynamics and Small-Scale Atmosphere-Ocean Processes in Coastal, Shelf and Polar Seas ArchiMer
Gommenginger, Christine; Chapron, Bertrand; Hogg, Andy; Buckingham, Christian; Fox-kemper, Baylor; Eriksson, Leif; Soulat, Francois; Ubelmann, Clément; Ocampo-torres, Francisco; Nardelli, Bruno Buongiorno; Griffin, David; Lopez-dekker, Paco; Knudsen, Per; Andersen, Ole; Stenseng, Lars; Stapleton, Neil; Perrie, William; Violante-carvalho, Nelson; Schulz-stellenfleth, Johannes; Woolf, David; Isern-fontanet, Jordi; Ardhuin, Fabrice; Klein, Patrice; Mouche, Alexis; Pascual, Ananda; Capet, Xavier; Hauser, Daniele; Stoffelen, Ad; Morrow, Rosemary; Aouf, Lotfi; Breivik, Øyvind; Fu, Lee-lueng; Johannessen, Johnny A.; Aksenov, Yevgeny; Bricheno, Lucy; Hirschi, Joel; Martin, Adrien Ch; Martin, Adiran P; Nurser, George; Polton, Jeff; Wolf, Judith; Johnsen, Harald; Soloviev, Alexander; Jacobs, Gregg A.; Collard, Fabrice; Groom, Steve; Kudryavtsev, Vladimir; Wilkin, John; Navarro, Victor; Babanin, Alex; Martin, Matthew; Siddorn, John; Saulter, Andrew; Rippeth, Tom; Emery, Bill; Maximenko, Nikolai; Romeiser, Roland; Graber, Hans; Azcarate, Aida Alvera; Hughes, Chris W.; Vandemark, Doug; Silva, Jose Da; Leeuwen, Peter Jan Van; Naveira-garabato, Alberto; Gemmrich, Johannes; Mahadevan, Amala; Marquez, Jose; Munro, Yvonne; Doody, Sam; Burbidge, Geoff.
High-resolution satellite images of ocean color and sea surface temperature reveal an abundance of ocean fronts, vortices and filaments at scales below 10 km but measurements of ocean surface dynamics at these scales are rare. There is increasing recognition of the role played by small scale ocean processes in ocean-atmosphere coupling, upper-ocean mixing and ocean vertical transports, with advanced numerical models and in situ observations highlighting fundamental changes in dynamics when scales reach 1 km. Numerous scientific publications highlight the global impact of small oceanic scales on marine ecosystems, operational forecasts and long-term climate projections through strong ageostrophic circulations, large vertical ocean velocities and mixed layer...
Tipo: Text Palavras-chave: Satellite; Air sea interactions; Upper ocean dynamics; Submesoscale; Coastal; Marginal ice zone; Radar; Along-track interferometry.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00510/62121/66325.pdf
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Wave Breaking in Slicks: Impacts on C-Band Quad-Polarized SAR Measurements ArchiMer
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
Registros recuperados: 9
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