Consulta: creatorFacets:"Ardhuin, Fanny"
Registros recuperados: 22
Data/hora: 09/06/2024 02:19:24

Partially supervised oil-slick detection by SAR imagery using kernel expansion
Provedor de dados: 5
Autores: 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

Les glaces de mer. Ca bouge !
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert.
Monitored by satellites and observed by the Ifremer's scientists, sea ices are under high supervision. Since 1992, the Ifremer is the only institute in the world to conduct a continuous mapping of sea ice drift.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-6363.pdf

La mer vue du ciel, la glace de mer est cartographiée en continu
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert.
Under the responsibility of French scientists, the Damocles program aims to evaluate the impact of the climate change on the Arctic ice floe. Some Bretons are involved: a team from the Ifremer Brest has been continuously mapping sea ice drift since 1992.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-6369.pdf

Enhanced Arctic Sea Ice Drift Estimation Merging Radiometer and Scatterometer Data
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert.
Satellites enable daily and global coverage of the polar oceans and provide a unique monitoring capability of sea ice dynamics. Sea ice drift maps can be estimated in Arctic from several satellite sensors, particularly from scatterometers and radiometers. This study presents the benefits of combining single drift fields at the same resolution into a "merged" field, built at three-and six-day lags during winters with a 62.5-km resolution. It is shown that combining these drift fields not only increases the reliability of the displacement estimation and the number of estimated vectors to almost a full ice covered area but also expands the time period over which these estimations are reliable from freeze until the melt onset. The autumn-winter-spring sea ice...
Tipo: Text
Palavras-chave: Arctic; Advanced Scatterometer (ASCAT); Drift; Merging; Scatterometry; Sea ice.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00088/19895/17729.pdf

Defining a Sea Ice Flag for Envisat Altimetry Mission
Provedor de dados: 5
Autores: Tran, N; Ardhuin, Fanny; Ezraty, Robert; Feng, H; Femenias, P.
This letter presents the development of a sea ice flag algorithm for the Envisat altimetry mission to detect sea ice corrupted sea surface height data within quality control processing. The algorithm takes advantage of having both passive and active microwave sensors on the same platform with coregistered measurements. Its performances have been evaluated based on collocations between the along-track Envisat data with reference maps built from combination of daily grids of sea ice concentration from SSM/I sensors and backscatter cross section from SeaWinds scatterometer on QuikSCAT satellite.
Tipo: Text
Palavras-chave: Sea ice; Remote sensing; Microwave measurements; Altimetry.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-5289.pdf

Evolution of the Arctic Ocean Salinity, 2007-08: Contrast between the Canadian and the Eurasian Basins
Provedor de dados: 5
Autores: Lique, Camille; Garric, Gilles; Treguier, Anne-marie; Barnier, Bernard; Ferry, Nicolas; Testut, Charles-emmanuel; Ardhuin, Fanny.
The authors investigate the variability of salinity in the Arctic Ocean and in the Nordic and Labrador Seas over recent years to see how the freshwater balance in the Arctic and the exchanges with the North Atlantic have been affected by the recent important sea ice melting, especially during the 2007 sea ice extent minimum. The Global Ocean Reanalysis and Simulations (GLORYS1) global ocean reanalysis based on a global coupled ocean sea ice model with an average of 12-km grid resolution in the Arctic Ocean is used in this regard. Although no sea ice data and no data under sea ice are assimilated, simulation over the 2001-09 period is shown to represent fairly well the 2007 sea ice event and the different components accounting for the ocean and sea ice...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00035/14637/11946.pdf

Antarctic icebergs distributions, 2002-2010
Provedor de dados: 5
Autores: Tournadre, Jean; Ardhuin, Fanny; Legresy, Benoit.
Interest for icebergs and their possible impact on southern ocean circulation and biology has increased during the recent years. While large tabular icebergs are routinely tracked and monitored using scatterometer data, the distribution of smaller icebergs (less than some km) is still largely unknown as they are difficult to detect operationally using conventional satellite data. In a recent study, Tournadre et al. (2008) showed that small icebergs can be detected, at least in open water, using high resolution (20 Hz) altimeter waveforms. In the present paper, we present an improvement of their method that allows, assuming a constant iceberg freeboard elevation and constant ice backscatter coefficient, to estimate the top-down iceberg surface area and...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00083/19444/17050.pdf

Les glaces de mer : ça bouge !
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert; Croize Fillon, Denis.
Tipo: Text
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-6342.pdf

Southern elephant seals from Kerguelen Islands confronted by Antarctic Sea ice. Changes in movements and in diving behaviour
Provedor de dados: 5
Autores: Bailleul, Frédéric; Charrassin, Jean-benoit; Ezraty, Robert; Ardhuin, Fanny; Mcmahon, Clive R.; Field, Iain C.; Guinet, Christophe.
The behaviour of southern elephant seals from Kerguelen Island (4950&amp;#8242;S, 7030&amp;#8242;E) was investigated in relation to the oceanographic regions of the Southern Ocean. The oceanographic and the seal behaviour data, including location and diving activity, were collected using a new generation of satellite-relayed devices measuring and transmitting pressure, temperature, and salinity along with locations. Dive duration, maximum diving depth, time spent at the bottom of the dives, and shape of dive profiles were compared between male and female seals, and were related to the oceanographic characteristics of areas prospected by the seals. Most animals travelled to the Antarctic shelf. However, during winter, adult females travelled away from the...
Tipo: Text
Palavras-chave: Mirounga leonina; Diving Behaviour; Pelagic environment; Benthic environment; Temperature profiles; Marine ecology.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2500.pdf

ASCAT/MetOp scatterometer data : first results for sea ice study
Provedor de dados: 5
Autores: 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

Validation and analysis of ocean parameters using ASCAT data
Provedor de dados: 5
Autores: Bentamy, Abderrahim; Ardhuin, Fanny; Croize-fillon, Denis; Queffeulou, Pierre.
This project aims to investigate the quality of ASCAT measurements as well as their use for oceanographic purposes. The accuracy of ASCAT retrievals will be mainly based on the use of collocated data from moored buoys, numerical weather prediction models, and satellites. The resulting collocated data will be used to explore the accuracy of the geophysical model function which relates the backscatter coefficients to surface wind vectors, as well as to assess the quality of ASCAT vector winds at global and local scales. Once this objective reached, it will enable to fully utilize the MetOp data for oceanographic applications. They will contribute to evaluate various estimates of ocean surface flux parameters required to force ocean general circulation...
Tipo: Text
Palavras-chave: Fluxes; Sea ice; Wind; Scatterometer; ASCAT; MetOp; Flux; Glaces de mer; Vent; Diffusiomètre; ASCAT; MetOp.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-1272.pdf

Optimum satellite remote sensing of the marine carbonate system using empirical algorithms in the global ocean, the Greater Caribbean, the Amazon Plume and the Bay of Bengal
Provedor de dados: 5
Autores: Land, Peter E.; Findlay, Helen S.; Shutler, Jamie D.; Ashton, Ian; Holding, Thomas; Grouazel, Antoine; Ardhuin, Fanny; Reul, Nicolas; Piolle, Jean-francois; Chapron, Bertrand; Quilfen, Yves; Bellerby, Richard G.j.; Bhadury, Punyasloke; Salisbury, Joseph; Vandemark, Douglas; Sabia, Roberto.
Improving our ability to monitor ocean carbonate chemistry has become a priority as the ocean continues to absorb carbon dioxide from the atmosphere. This long-term uptake is reducing the ocean pH; a process commonly known as ocean acidification. The use of satellite Earth Observation has not yet been thoroughly explored as an option for routinely observing surface ocean carbonate chemistry, although its potential has been highlighted. We demonstrate the suitability of using empirical algorithms to calculate total alkalinity (AT) and total dissolved inorganic carbon (CT), assessing the relative performance of satellite, interpolated in situ, and climatology datasets in reproducing the wider spatial patterns of these two variables. Both AT and CT in situ...
Tipo: Text
Palavras-chave: Carbonate chemistry; Earth observation; Ocean acidification; Total alkalinity; Dissolved inorganic carbon; SMOS; Aquarius; CORA; HadGEM2-ES.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00591/70267/68368.pdf

Estimates of ocean wave heights and attenuation in sea ice using the SAR wave mode on Sentinel-1A
Provedor de dados: 5
Autores: 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

Validation of Arctic sea ice drift with IABP buoys
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert.
Satellites enable daily and global coverage of the polar oceans, providing an unique monitoring capability of sea ice dynamics over Arctic and Antarctic. Available geophysical parameters include ice concentration, extent, type and sea ice drift. Backscatter map from SeaWinds/QuikSCAT and brightness temperature maps from Special Sensor Microwave Imager (SSM/I) are available at a pixel resolution of 12,5 km from which ice drift can be estimated for each sensor. Since 1999, IFREMER makes available a "Merged" sea ice drift data set based on the combination of these drifts at 3 and 6-day lags at the grid resolution of 62,5 km. It has been demonstrated that combining these drifts increases the number of valid vectors.  In this paper, the validation of this...
Tipo: Text
Palavras-chave: Arctic; Buoys; Drift; Sea ice; AMSR E; Radiometer; Scatterometer; Arctique; Bouées; Dérive; Glaces de mer; AMSR E; Radiomètre; Diffusiomètre.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-1292.pdf

L'IFREMER met en cartes les glaces polaires
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert.
The fourth International Polar Year (API) was officially launched at the Palais de la Découverte in Paris in the beginning of March. This international research effort will spread over two years. The polar specialists hope for an acceleration of the current programs, especially those dealing with the impact of climate warming on polar regions. Paul Tréguer, member of the French PAPI sponsoring committee, summarizes the different issues. And two Ifremer scientists explain how they've been observing, since 1992, the shrinking of the sea ice cover in the North Pole
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-6367.pdf

Operational oil-slick characterization by SAR imagery and synergistic data
Provedor de dados: 5
Autores: Ardhuin, Fanny; Mercier, G; Collard, F; Garello, R.
A methodology is proposed for the semiautomatic detection, characterization, and classification of slicks detected in C-band Synthetic Aperture Radar (SAR). For the first detection step, automatic algorithms were tested on Environmental Research Satellite (ERS) and Environmental Satellite (EnviSat) images acquired during the Prestige tanker accident. These tests reveal that simple filter or segmentation methods efficiently detect slicks with high contrasts and simple shapes, while a new and more complex multiscale method is able to detect a wider range of slicks. The characteristics of automatically detected slicks are then combined with meteooceanic data in order to eliminate slicks related to wind anomalies and current fronts. The data suggest that...
Tipo: Text
Palavras-chave: Synthetic aperture radar SAR; Satellite measurement; Oil pollution; Image analysis.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-1132.pdf

Quand la voie du Nord s'ouvrira au trafic maritime
Provedor de dados: 5
Autores: Ardhuin, Fanny.
With the melting of the ice floe, the Arctic Ocean could become navigable. A new maritime way that would be an exciting alternative to the existing routes.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-6368.pdf

Observation and parameterization of small icebergs: Drifting breakwaters in the southern ocean
Provedor de dados: 5
Autores: Ardhuin, Fabrice; Tournadre, Jean; Queffeulou, Pierre; Ardhuin, Fanny; Collard, Fabrice.
The variability of small-size iceberg distributions is revealed from a novel analysis of satellite altimeter data. A strong annual cycle is modulated by pulse-like events confined to single ocean basins, with dense iceberg populations in the South Atlantic in 2004-2005, and in the South Pacific in 2008. Anomalies in sea surface temperatures of the order of 1 degrees C may be related to the iceberg distribution. Icebergs also appear very strongly associated with anomalies in the heights of ocean waves. A preliminary parameterization of wave blocking by icebergs significantly reduces wave model errors in the region south of 45 degrees South, and has a perceptible influence on all the west coasts of the Southern hemisphere. (C) 2011 Elsevier Ltd. All rights...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00044/15535/13317.pdf

Variability and trends in Laptev Sea ice outflow between 1992-2011
Provedor de dados: 5
Autores: Krumpen, T.; Janout, M.; Hodges, K. I.; Gerdes, R.; Ardhuin, Fanny; Hoelemann, J. A.; Willmes, S.
Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average total winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48x10(5) km(2). The average transport across the NB (2.87x10(5) km(2)) is thereby higher than across the EB (0.61x10(5) km(2)), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85x10(5) km(2) decade(-1), p &gt; 0.95), dominated by increasing export through the EB (0.55x10(5) km(2) decade(-1), p &gt; 0.90), while the increase in export across the NB is smaller...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00137/24782/22832.pdf

Comment se forme un pancake aux pôles ? ou l'importance d'observer la banquise...
Provedor de dados: 5
Autores: Ardhuin, Fanny; Ezraty, Robert; Croize-fillon, Denis.
Sea water freezes at a temperature of -1,8°C, creating scattered pieces of ice similar to pancakes. When agglomerating, these pieces end up forming a compact surface... the ice floe!
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/acte-6365.pdf

Iceberg detection in open water by altimeter waveform analysis
Provedor de dados: 5
Autores: Tournadre, Jean; Whitmer, K; Ardhuin, Fanny.
Small icebergs (edge lengths &lt;1 km) are difficult to detect and track. In a recently published study, it was demonstrated that small targets (ships, islets,...) emerging from the sea can be detected by the analysis of high-rate altimeter waveforms. The analysis of Jason altimeter data revealed that small icebergs also have a detectable signature in the thermal noise part of the altimeter waveforms for open water. These signatures are very similar to that of transponders and are almost deterministic. An automated method based on the detection of parabolic shapes in the thermal part of the waveforms by analysis of the convolution product with a filter has been developed and applied to 1 year of Jason high-rate waveform data. In addition, the minimum...
Tipo: Text
Palavras-chave: Antarctica; Iceberg; Altimeter waveform.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4530.pdf

Remote sensing of sea ice: advances during the DAMOCLES project
Provedor de dados: 5
Autores: Heygster, G.; Alexandrov, V.; Dybkjaer, G.; Von Hoyningen-huene, W.; Ardhuin, Fanny; Katsev, I. L.; Kokhanovsky, A.; Lavergne, Thomas; Malinka, A. V.; Melsheimer, C.; Pedersen, L. Toudal; Prikhach, A. S.; Saldo, R.; Tonboe, Rasmus; Wiebe, H.; Zege, E. P.
In the Arctic, global warming is particularly pronounced so that we need to monitor its development continuously. On the other hand, the vast and hostile conditions make in situ observation difficult, so that available satellite observations should be exploited in the best possible way to extract geophysical information. Here, we give a resume of the sea ice remote sensing efforts of the European Union's (EU) project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies). In order to better understand the seasonal variation of the microwave emission of sea ice observed from space, the monthly variations of the microwave emissivity of first-year and multi-year sea ice have been derived for the frequencies of the...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00130/24174/22316.pdf