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| Registros recuperados: 12 | |
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| Bentamy, Abderrahim; Croize-fillon, Denis; Perigaud, C.. |
| The new scatterometer Advanced SCATterometer (ASCAT) onboard MetOp-A satellite provides surface wind speed and direction over global ocean with a spatial resolution of 25 km square over two swaths of 550 km widths. The accuracy of ASCAT wind retrievals is determined through various comparisons with moored buoys. The comparisons indicate that the remotely sensed wind speeds and directions agree well with buoy data. The root-mean-squared differences of the wind speed and direction are less than 1.72 m/s and 18 degrees, respectively. At global scale, ASCAT winds are compared with surface winds derived from QuikSCAT scatterometer. The results confirm the buoy analyses, especially for wind speed ranging between 3 m/s and 20 m/s. For higher wind conditions.... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00004/11549/8149.pdf |
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| Rascle, N; Ardhuin, Fabrice; Queffeulou, Pierre; Croize-fillon, Denis. |
| Ocean surface mixing and drift are influenced by the mixed layer depth, buoyancy fluxes and currents below the mixed layer. Drift and mixing are also functions of the surface Stokes drift U, volume Stokes transport T-s, a wave breaking height scale H-swg, and the flux of energy from waves to ocean turbulence Phi(oc). Here we describe a global database of these parameters, estimated from a well-validated numerical wave model, that uses traditional forms of the wave generation and dissipation parameterizations, and covers the years 2003-2007. Compared to previous studies, the present work has the advantage of being consistent with the known physical processes that regulate the wave field and the air-sea fluxes, and also consistent with a very large number of... |
| Tipo: Text |
Palavras-chave: Ocean mixing; Surface drift; Air sea fluxes; Surface gravity waves. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-5903.pdf |
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| Bentamy, Abderrahim; Ayina, Ludos-herve; Queffeulou, Pierre; Croize-fillon, Denis; Kerbaol, Vincent. |
| Several scientific programs, including the Mediterranean Forecasting System Toward Environmental Predictions (MFSTEP project), request high space and time resolutions of surface wind speed and direction. The purpose of this paper is to focus on surface wind improvements over the global Mediterranean Sea, based on the blending near real time remotely sensed wind observations and ECMWF wind analysis. Ocean surface wind observations are retrieved from QuikSCAT scatterometer and from SSM/I radiometers available at near real time at Meteo-France. Using synchronous satellite data, the number of remotely sensed data available for each analysis epoch ( 00: 00 h; 06: 00 h; 12: 00 h; 18: 00 h) is not uniformly distributed as a function of space and time. On average... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3528.pdf |
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| Ardhuin, Fanny; Ezraty, Robert; Croize-fillon, Denis. |
| Backscatter values from scatterometers are commonly used to estimate wind field over oceans, their ability to monitor sea ice coverage, age and drift has been also demonstrated. Here, ASCAT backscatter coefficient has been processed for sea ice geophysical interpretation in order to increase the long time series of ice parameters already available. It has been shown that incidence- adjustment is mandatory for geophysical meaning, the backscatter maps enable the discrimination between multi year ice and first year ice, these maps can also be used as a basic product for sea ice drift estimation. (Copyright : European Space Agency ISBN 978-92-9221-239-1 ISSN 1609-042X) |
| Tipo: Text |
Palavras-chave: Sea ice; Wind; Scatterometer; ASCAT; MetOp; Glaces de mer; Vent; Diffusiomètre; ASCAT; MetOp. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/acte-6970.pdf |
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| Bentamy, Abderrahim; Croize-fillon, Denis. |
| This article deals with the calculation and validation of daily surface wind vector fields from wind speed and direction observations derived from Advanced SCATterometer (ASCAT) scatterometer measurements over the global ocean. According to the ASCAT sampling scheme, the objective method allowing for the determination of regular in space and time wind speed and direction fields uses ASCAT observations as well as European Centre for Medium Weather Forecasts (ECMWF) analyses. The latter are considered as external drift for the kriging method and as the temporal interpolation basis for ASCAT retrievals. This study focuses on the investigation of the capability of the method to add valuable wind information to the operational atmospheric analyses and on the... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00043/15440/12808.pdf |
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| Bentamy, Abderrahim; Croize-fillon, Denis. |
| The main objective of this paper is to thoroughly examine the remotely sensed wind characteristics around the coasts of Brittany as well as some more specific areas. The offshore wind power potential is then assessed. To achieve this objective, information on wind speed and direction with sufficient spatial and temporal sampling under all weather conditions and during day and night is required. This study uses more than 12 years (December 1999–December 2012) of consistent remotely sensed data retrieved from the ASCAT and QuikSCAT scatterometers to estimate the conventional moments and associated wind distribution parameters. The latter are comparable to wind observations from meteorological stations. Furthermore, combining in-situ and scatterometer wind... |
| Tipo: Text |
Palavras-chave: Wind; Energy; Scatterometer; Remote sensing; Brittany. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00175/28648/28552.pdf |
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| Bentamy, Abderrahim; Croize-fillon, Denis; Queffeulou, Pierre; Liu, C.; Roquet, H.. |
| High resolution surface wind fields covering the global ocean, estimated from remotely sensed wind data and ECMWF wind analyses, have been available since 2005 with a spatial resolution of 0.25 degrees in longitude and latitude, and a temporal resolution of 6h. Their quality is investigated through various comparisons with surface wind vectors from 190 buoys moored in various oceanic basins, from research vessels and from QuikSCAT scatterometer data taken during 2005-2006. The NCEP/NCAR and NCDC blended wind products are also considered. The comparisons performed during January-December 2005 show that speeds and directions compare well to in-situ observations, including from moored buoys and ships, as well as to the remotely sensed data. The... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00004/11546/10549.pdf |
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| Bentamy, Abderrahim; Grodsky, Semyon A.; Carton, James A.; Croize-fillon, Denis; Chapron, Bertrand. |
| Surface winds from two scatterometers, the Advanced scatterometer (ASCAT), available since 2007, and QuikSCAT, which was available through November 2009, show persistent differences during their period of overlap. This study examines a set of collocated observations during a 13-month period November 2008 through November 2009, to evaluate the causes of these differences. A difference in the operating frequency of the scatterometers leads to differences that this study argues depend on rain rate, wind velocity, and SST. The impact of rainfall on the higher frequency QuikSCAT introduces biases of up to 1 m s(-1) in the tropical convergence zones and along the western boundary currents even after rain flagging is applied. This difference from ASCAT is reduced... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00070/18126/15691.pdf |
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| Registros recuperados: 12 | |
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