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| Registros recuperados: 15 | |
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| González-haro, Cristina; Ponte, Aurelien; Autret, Emmanuelle. |
| The expected amplitude of fixed-point sea surface temperature (SST) fluctuations induced by barotropic and baroclinic tidal flows is estimated from tidal current atlases and SST observations. The fluctuations considered are the result of the advection of pre-existing SST fronts by tidal currents. They are thus confined to front locations and exhibit fine-scale spatial structures. The amplitude of these tidally induced SST fluctuations is proportional to the scalar product of SST frontal gradients and tidal currents. Regional and global estimations of these expected amplitudes are presented. We predict barotropic tidal motions produce SST fluctuations that may reach amplitudes of 0.3 K. Baroclinic (internal) tides produce SST fluctuations that may reach... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Satellite observations; Tidal currents; Internal tides. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00589/70075/68048.pdf |
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| Picart, Stephane Saux; Tandeo, Pierre; Autret, Emmanuelle; Gausset, Blandine. |
| Machine learning techniques are attractive tools to establish statistical models with a high degree of non linearity. They require a large amount of data to be trained and are therefore particularly suited to analysing remote sensing data. This work is an attempt at using advanced statistical methods of machine learning to predict the bias between Sea Surface Temperature (SST) derived from infrared remote sensing and ground “truth” from drifting buoy measurements. A large dataset of collocation between satellite SST and in situ SST is explored. Four regression models are used: Simple multi-linear regression, Least Square Shrinkage and Selection Operator (LASSO), Generalised Additive Model (GAM) and random forest. In the case of geostationary satellites for... |
| Tipo: Text |
Palavras-chave: Machine learning; Systematic error; Sea surface temperature; Random forest. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00426/53797/54721.pdf |
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| Mcmahon, Cr; Autret, Emmanuelle; Houghton, Jdr; Lovell, P; Myers, Ae; Hays, Gc. |
| Climate change is perhaps the most pressing and urgent environmental issue facing the world today. However our ability to predict and quantify the consequences of this change is severely limited by the paucity of in situ oceanographic measurements. Marine animals equipped with sophisticated oceanographic data loggers to study their behavior offer one solution to this problem because marine animals range widely across the world's ocean basins and visit remote and often inaccessible locations. However, unlike the information being collected from conventional oceanographic sensing equipment, which has been validated, the data collected from instruments deployed on marine animals over long periods has not. This is the first long-term study to validate in situ... |
| Tipo: Text |
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| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00286/39727/38205.pdf |
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| Dash, Prasanjit; Ignatov, Alexander; Martin, Matthew; Donlon, Craig; Brasnett, Bruce; Reynolds, Richard W.; Banzon, Viva; Beggs, Helen; Cayula, Jean-francois; Chao, Yi; Grumbine, Robert; Maturi, Eileen; Harris, Andy; Mittaz, Jonathan; Sapper, John; Chin, Toshio M.; Vazquez-cuervo, Jorge; Armstrong, Edward M.; Gentemann, Chelle; Cummings, James; Piolle, Jean-francois; Autret, Emmanuelle; Roberts-jones, Jonah; Ishizaki, Shiro; Hoyer, Jacob L.; Poulter, Dave. |
| There are a growing number of level 4 (L4; gap-free gridded) sea surface temperature (SST) products generated by blending SST data from various sources which are available for use in a wide variety of operational and scientific applications. In most cases, each product has been developed for a specific user community with specific requirements guiding the design of the product. Consequently differences between products are implicit. In addition, anomalous atmospheric conditions, satellite operations and production anomalies may occur which can introduce additional differences. This paper describes a new web-based system called the L4 SST Quality Monitor (L4-SQUAM) developed to monitor the quality of L4 SST products. L4-SQUAM intercompares thirteen L4... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Intercomparison; Climate data; Sea ice; Data centers. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00101/21188/19798.pdf |
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| Souza, J. M. A. C.; Chapron, Bertrand; Autret, Emmanuelle. |
| The surface signature of Agulhas rings propagating across the South Atlantic Ocean is observed based on three independent data sets: Advanced Microwave Scanning Radiometer for the Earth Observing System/Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) (TMI/AMSR-E) satellite sea surface temperature, Argo profiling floats and a merged winds product derived from scatterometer observations and reanalysis results. A persistent pattern of cold (negative) sea surface temperature (SST) anomalies in the eddy core, with warm (positive) anomalies at the boundary, is revealed. This pattern contrasts with the classical idea of a warm core anticyclone. Taking advantage of a moving reference frame corresponding to the altimetry-detected Agulhas rings,... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00208/31893/30318.pdf |
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| Tandeo, Pierre; Ailliot, Pierre; Autret, Emmanuelle. |
| Satellites provide important information on many meteorological and oceanographic variables. State-space models are commonly used to analyse such data sets with measurement errors. In this work, we propose to extend the usual linear and Gaussian state-space to analyse time series with irregular time sampling, such as the one obtained when keeping all the satellite observations available at some specific location. We discuss the parameter estimation using a method of moment and the method of maximum likelihood. Simulation results indicate that the method of moment leads to a computationally efficient and numerically robust estimation procedure suitable for initializing the Expectation-Maximisation algorithm, which is combined with a standard numerical... |
| Tipo: Text |
Palavras-chave: State-space model; Irregular sampling; Ornstein-Uhlenbeck process; EM algorithm; Sea surface temperature. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/15047/12441.pdf |
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| Tandeo, Pierre; Autret, Emmanuelle; Piolle, Jean-francois; Tournadre, Jean; Ailliot, Pierre. |
| The Advanced Along-Track Scanning Radiometer (AATSR) onboard Envisat is designed to provide very accurate measurements of sea surface temperature (SST). Using colocated in situ drifting buoys, a dynamical matchup database (MDB) is used to assess the AATSR-derived SST products more precisely. SST biases are then computed. Currently, Medspiration AATSR SST biases are discrete values and can introduce artificial discontinuities in AATSR level-2 SST fields. The new AATSR SST biases presented in this letter are continuous. They are computed, for nighttime and best proximity confidence data, by linear regression with different MDB covariables (wind speed, latitude, aerosol optical depth, etc.). As found, the difference between dual-view and nadir-only SST... |
| Tipo: Text |
Palavras-chave: Validation; Sea surface temperature (SST); Remote sensing; Advanced Along Track Scanning Radiometer (AATSR). |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6135.pdf |
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| Vandermeirsch, Frederic; Charraudeau, Romain; Bonnat, Armel; Fichaut, Michele; Maillard, Catherine; Gaillard, Fabienne; Autret, Emmanuelle. |
| The Bay of Biscay climatology is the synthesis of all the in situ data collected in the bay of Biscay area as far as 15°W, in the 20th century and mainly by IFREMER, SHOM, and WDCA. It shows temperature and salinity monthly information through the whole water column with a 1/10 degree resolution. The resulting atlas was produced by an optimal analysis which can reflect different scales: shelf and abyssal plain. A fine scale on the coast reveals all the local effects, including plume and upwelling, and a large scale on the shelf where a slower signal is obtained due to the large scale circulation |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00029/14039/11232.pdf |
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| Gonzalez Garcia, Laura; Pierce, Graham J.; Autret, Emmanuelle; Torres-palenzuela, Jesus M.. |
| Blue whales are sighted every year around the Azores islands, which apparently provide an important seasonal foraging area. In this paper we aim to characterize habitat preferences and analyze the temporal distribution of blue whales around São Miguel Island. To do so, we applied Generalized Additive Models to an opportunistic cetacean occurrence dataset and remotely sensed environmental data on bathymetry, sea surface temperature, chlorophyll concentration and altimetry. We provide a brief description of the oceanography of the area, emphasizing its high spatio-temporal variability. In order to capture this dynamism, we used environmental data with two different spatial resolutions (low and high) and three different temporal resolutions (daily, weekly and... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00460/57145/59069.pdf |
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| Von Schuckmann, Karina; Le Traon, Pierre-yves; Smith, Neville; Pascual, Ananda; Brasseur, Pierre; Fennel, Katja; Djavidnia, Samy; Aaboe, Signe; Alvarez Fanjul, Enrique; Autret, Emmanuelle; Axell, Lars; Aznar, Roland; Benincasa, Mario; Bentamy, Abderrahim; Boberg, Fredrik; Bourdalle-badie, Romain; Nardelli, Bruno Buongiorno; Brando, Vittorio E.; Bricaud, Clement; Breivik, Lars-anders; Brewin, Robert J. W.; Capet, Arthur; Ceschin, Adrien; Ciliberti, Stefania; Cossarini, Gianpiero; De Alfonso, Marta; De Pascual Collar, Alvaro; De Kloe, Jos; Deshayes, Julie; Desportes, Charles; Drevillon, Marie; Drillet, Yann; Droghei, Riccardo; Dubois, Clotilde; Embury, Owen; Etienne, Helene; Fratianni, Claudia; Garcia Lafuente, Jesus; Garcia Sotillo, Marcos; Garric, Gilles; Gasparin, Florent; Gerin, Riccardo; Good, Simon; Gourrion, Jerome; Gregoire, Marilaure; Greiner, Eric; Guinehut, Stephanie; Gutknecht, Elodie; Hernandez, Fabrice; Hernandez, Olga; Hoyer, Jacob; Jackson, Laura; Jandt, Simon; Josey, Simon; Juza, Melanie; Kennedy, John; Kokkini, Zoi; Korres, Gerasimos; Kouts, Mariliis; Lagemaa, Priidik; Lavergne, Thomas; Le Cann, Bernard; Legeais, Jean-francois; Lemieux-dudon, Benedicte; Levier, Bruno; Lien, Vidar; Maljutenko, Ilja; Manzano, Fernando; Marcos, Marta; Marinova, Veselka; Masina, Simona; Mauri, Elena; Mayer, Michael; Melet, Angelique; Melin, Frederic; Meyssignac, Benoit; Monier, Maeva; Muller, Malte; Mulet, Sandrine; Naranjo, Cristina; Notarstefano, Giulio; Paulmier, Aurelien; Perez Gomez, Begona; Perez Gonzalez, Irene; Peneva, Elisaveta; Perruche, Coralie; Peterson, K. Andrew; Pinardi, Nadia; Pisano, Andrea; Pardo, Silvia; Poulain, Pierre-marie; Raj, Roshin P.; Raudsepp, Urmas; Ravdas, Michaelis; Reid, Rebecca; Rio, Marie-hélène; Salon, Stefano; Samuelsen, Annette; Sammartino, Michela; Sammartino, Simone; Sando, Anne Britt; Santoleri, Rosalia; Sathyendranath, Shubha; She, Jun; Simoncelli, Simona; Solidoro, Cosimo; Stoffelen, Ad; Storto, Andrea; Szerkely, Tanguy; Tamm, Susanne; Tietsche, Steffen; Tinker, Jonathan; Tintore, Joaquin; Trindade, Ana; Van Zanten, Daphne; Vandenbulcke, Luc; Verhoef, Anton; Verbrugge, Nathalie; Viktorsson, Lena; Wakelin, Sarah L.; Zacharioudaki, Anna; Zuo, Hao. |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00601/71276/71010.pdf |
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| Autret, Emmanuelle; Gaillard, Fabienne. |
| In the previous letter, we briefly presented the analysis system operational at the Coriolis datacen-ter. This system both synthetises data sets by pro-ducing temperature and salinity gridded fields and checks for quality the data from the Coriolis data-base in real time. We will focus here on this latter application of the system. We will discuss of the use of the analysis tool to perform the real time and delayed mode quality control (QC), particularly of the ARGO profilers. Those two modes of QC are fundamentally different. Real time QC are meant to flag the data according to pre-defined quality levels, these tests must not slow down the data flow, they are therefore only qualitative. The delayed mode QC has to be quantitative, one wish to detect and... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-6423.pdf |
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| Merchant, C. J.; Filipiak, M. J.; Le Borgne, P.; Roquet, H.; Autret, Emmanuelle; Piolle, Jean-francois; Lavender, S.. |
| We characterize near-surface ocean diurnal warm-layer events, using satellite observations and fields from numerical weather forecasting. The study covers April to September, 2006, over the area 11 degrees W to 17 degrees E and 35 degrees N to 57 degrees N, with 0.1 degrees cells. We use hourly satellite SSTs from which peak amplitudes of diurnal cycles in SST (dSSTs) can be estimated with error similar to 0.3 K. The diurnal excursions of SST observed are spatially and temporally coherent. The largest dSSTs exceed 6 K, affect 0.01% of the surface, and are seen in the Mediterranean, North and Irish Seas. There is an anti-correlation between the magnitude and the horizontal length scale of dSST events. Events wherein dSST exceeds 4 K have length scales of... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00004/11560/8156.pdf |
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| Coatanoan, Christine; Carval, Thierry; Petit De La Villeon, Loic; Autret, Emmanuelle; Gouriou, Yves; Gourmelen, Loic. |
| An operational oceanographic system is being developed in France to monitor and forecast ocean behavior. It is composed of three projects: - Sea-surface observation using satellite sensors, - ln situ measurements from ships, moored or drifting autonomous systems, - Assimilation of in-situ and satellite data in an ocean circulation modal. Coriolis contributes to the in situ part of this system,with the objective of developing continuous,automatic,and permanent observation networks. The data collected will enable water properties to be mapped, such as temperature, and ocean circulation. (NOT CONTROLLED OCR] |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-4691.pdf |
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| Registros recuperados: 15 | |
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