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| Registros recuperados: 39 | |
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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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| Tournadre, Jean; Chapron, Bertrand; Reul, Nicolas; Vandemark, D. |
| [1] About 5% of Ku-band altimeter ocean data are degraded by the occurrence of high radar return cross sections (sigma(0)), usually called sigma(0) blooms. During blooms, which occur during no or low wind conditions, the mean altimeter waveform can significantly depart from the expected shape. In about 60% of the cases the waveforms are distorted to such an extent that either the range tracker loses lock or the off-nadir angle estimate becomes unrealistic. The analysis of high data rate altimeter waveforms during bloom events reveals the presence of V-shaped patterns similar to the ones observed during rain events. These patterns trace small-scale (i.e., smaller than the altimeter footprint) changes in surface backscatter. Such variations of surface... |
| Tipo: Text |
Palavras-chave: Slick; Sigma blooms; Altimeter waveforms. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1353.pdf |
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| Quilfen, Yves; Tournadre, Jean; Chapron, Bertrand. |
| [1] Extreme weather events such as tropical cyclones are difficult to observe with conventional means. Satellite-based observations provide essential measurements of key parameters governing tropical cyclones. They are critical for short-term forecasting. Radiometers onboard the Defense Meteorological Satellite Program satellite series, WindSat and Tropical Rainfall Measuring Mission satellites, scatterometers onboard the ERS, ADEOS, and QuikScat satellites offer unprecedented synoptic observations of surface wind and atmospheric liquid water content, revealing the storm structures with good accuracy. However, satellite estimates do not provide direct measurements of geophysical parameters and can suffer from limitations linked to the sensors... |
| Tipo: Text |
Palavras-chave: Mesearement limitations; Dual frequency altimeter; High resolution measurement; Tropical cyclone. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1033.pdf |
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| Abdalla, Saleh; Abdeh Kolahchi, Abdolnabi; Adusumilli, Susheel; Aich Bhowmick, Suchandra; Alou-font, Eva; Amarouche, Laiba; Andersen, Ole Baltazar; Antich, Helena; Aouf, Lotfi; Arbic, Brian; Armitage, Thomas; Arnault, Sabine; Artana, Camila; Aulicino, Giuseppe; Ayoub, Nadia; Badulin, Sergei; Baker, Steven; Banks, Chris; Bao, Lifeng; Barbetta, Silvia; Barceló-llull, Bàrbara; Barlier, François; Basu, Sujit; Bauer-gottwein, Peter; Becker, Matthias; Beckley, Brian; Bellefond, Nicole; Belonenko, Tatyana; Benkiran, Mounir; Benkouider, Touati; Bennartz, Ralf; Benveniste, Jérôme; Bercher, Nicolas; Berge-nguyen, Muriel; Bettencourt, Joao; Blarel, Fabien; Blazquez, Alejandro; Blumstein, Denis; Bonnefond, Pascal; Borde, Franck; Bouffard, Jérôme; Boy, François; Boy, Jean-paul; Brachet, Cédric; Brasseur, Pierre; Braun, Alexander; Brocca, Luca; Brockley, David; Brodeau, Laurent; Brown, Shannon; Bruinsma, Sean; Bulczak, Anna; Buzzard, Sammie; Cahill, Madeleine; Calmant, Stéphane; Calzas, Michel; Camici, Stefania; Cancet, Mathilde; Capdeville, Hugues; Carabajal, Claudia Cristina; Carrere, Loren; Cazenave, Anny; Chassignet, Eric P.; Chauhan, Prakash; Cherchali, Selma; Chereskin, Teresa; Cheymol, Cecile; Ciani, Daniele; Cipollini, Paolo; Cirillo, Francesca; Cosme, Emmanuel; Coss, Steve; Cotroneo, Yuri; Cotton, David; Couhert, Alexandre; Coutin-faye, Sophie; Crétaux, Jean-françois; Cyr, Frederic; D’ovidio, Francesco; Darrozes, José; David, Cedric; Dayoub, Nadim; De Staerke, Danielle; Deng, Xiaoli; Desai, Shailen; Desjonqueres, Jean-damien; Dettmering, Denise; Di Bella, Alessandro; Díaz-barroso, Lara; Dibarboure, Gerald; Dieng, Habib Boubacar; Dinardo, Salvatore; Dobslaw, Henryk; Dodet, Guillaume; Doglioli, Andrea; Domeneghetti, Alessio; Donahue, David; Dong, Shenfu; Donlon, Craig; Dorandeu, Joël; Drezen, Christine; Drinkwater, Mark; Du Penhoat, Yves; Dushaw, Brian; Egido, Alejandro; Erofeeva, Svetlana; Escudier, Philippe; Esselborn, Saskia; Exertier, Pierre; Fablet, Ronan; Falco, Cédric; Farrell, Sinead Louise; Faugere, Yannice; Femenias, Pierre; Fenoglio, Luciana; Fernandes, Joana; Fernández, Juan Gabriel; Ferrage, Pascale; Ferrari, Ramiro; Fichen, Lionel; Filippucci, Paolo; Flampouris, Stylianos; Fleury, Sara; Fornari, Marco; Forsberg, Rene; Frappart, Frédéric; Frery, Marie-laure; Garcia, Pablo; Garcia-mondejar, Albert; Gaudelli, Julia; Gaultier, Lucile; Getirana, Augusto; Gibert, Ferran; Gil, Artur; Gilbert, Lin; Gille, Sarah; Giulicchi, Luisella; Gómez-enri, Jesús; Gómez-navarro, Laura; Gommenginger, Christine; Gourdeau, Lionel; Griffin, David; Groh, Andreas; Guerin, Alexandre; Guerrero, Raul; Guinle, Thierry; Gupta, Praveen; Gutknecht, Benjamin D.; Hamon, Mathieu; Han, Guoqi; Hauser, Danièle; Helm, Veit; Hendricks, Stefan; Hernandez, Fabrice; Hogg, Anna; Horwath, Martin; Idžanović, Martina; Janssen, Peter; Jeansou, Eric; Jia, Yongjun; Jia, Yuanyuan; Jiang, Liguang; Johannessen, Johnny A.; Kamachi, Masafumi; Karimova, Svetlana; Kelly, Kathryn; Kim, Sung Yong; King, Robert; Kittel, Cecile M.m.; Klein, Patrice; Klos, Anna; Knudsen, Per; Koenig, Rolf; Kostianoy, Andrey; Kouraev, Alexei; Kumar, Raj; Labroue, Sylvie; Lago, Loreley Selene; Lambin, Juliette; Lasson, Léa; Laurain, Olivier; Laxenaire, Rémi; Lázaro, Clara; Le Gac, Sophie; Le Sommer, Julien; Le Traon, Pierre-yves; Lebedev, Sergey; Léger, Fabien; Legresy, Benoı̂t; Lemoine, Frank; Lenain, Luc; Leuliette, Eric; Levy, Marina; Lillibridge, John; Liu, Jianqiang; Llovel, William; Lyard, Florent; Macintosh, Claire; Makhoul Varona, Eduard; Manfredi, Cécile; Marin, Frédéric; Mason, Evan; Massari, Christian; Mavrocordatos, Constantin; Maximenko, Nikolai; Mcmillan, Malcolm; Medina, Thierry; Melet, Angelique; Meloni, Marco; Mertikas, Stelios; Metref, Sammy; Meyssignac, Benoit; Michaël, Ablain; Minster, Jean-françois; Moreau, Thomas; Moreira, Daniel; Morel, Yves; Morrow, Rosemary; Moyard, John; Mulet, Sandrine; Naeije, Marc; Nerem, Robert Steven; Ngodock, Hans; Nielsen, Karina; Nilsen, Jan Even Øie; Niño, Fernando; Nogueira Loddo, Carolina; Noûs, Camille; Obligis, Estelle; Otosaka, Inès; Otten, Michiel; Oztunali Ozbahceci, Berguzar; P. Raj, Roshin; Paiva, Rodrigo; Paniagua, Guillermina; Paolo, Fernando; Paris, Adrien; Pascual, Ananda; Passaro, Marcello; Paul, Stephan; Pavelsky, Tamlin; Pearson, Christopher; Penduff, Thierry; Peng, Fukai; Perosanz, Felix; Picot, Nicolas; Piras, Fanny; Poggiali, Valerio; Poirier, Étienne; Ponce De León, Sonia; Prants, Sergey; Prigent, Catherine; Provost, Christine; Pujol, M-isabelle; Qiu, Bo; Quilfen, Yves; Rami, Ali; Raney, R. Keith; Raynal, Matthias; Remy, Elisabeth; Rémy, Frédérique; Restano, Marco; Richardson, Annie; Richardson, Donald; Ricker, Robert; Ricko, Martina; Rinne, Eero; Rose, Stine Kildegaard; Rosmorduc, Vinca; Rudenko, Sergei; Ruiz, Simón; Ryan, Barbara J.; Salaün, Corinne; Sanchez-roman, Antonio; Sandberg Sørensen, Louise; Sandwell, David; Saraceno, Martin; Scagliola, Michele; Schaeffer, Philippe; Scharffenberg, Martin G.; Scharroo, Remko; Schiller, Andreas; Schneider, Raphael; Schwatke, Christian; Scozzari, Andrea; Ser-giacomi, Enrico; Seyler, Frederique; Shah, Rashmi; Sharma, Rashmi; Shaw, Andrew; Shepherd, Andrew; Shriver, Jay; Shum, C.k.; Simons, Wim; Simonsen, Sebatian B.; Slater, Thomas; Smith, Walter; Soares, Saulo; Sokolovskiy, Mikhail; Soudarin, Laurent; Spatar, Ciprian; Speich, Sabrina; Srinivasan, Margaret; Srokosz, Meric; Stanev, Emil; Staneva, Joanna; Steunou, Nathalie; Stroeve, Julienne; Su, Bob; Sulistioadi, Yohanes Budi; Swain, Debadatta; Sylvestre-baron, Annick; Taburet, Nicolas; Tailleux, Rémi; Takayama, Katsumi; Tapley, Byron; Tarpanelli, Angelica; Tavernier, Gilles; Testut, Laurent; Thakur, Praveen K.; Thibaut, Pierre; Thompson, Luanne; Tintoré, Joaquín; Tison, Céline; Tourain, Cédric; Tournadre, Jean; Townsend, Bill; Tran, Ngan; Trilles, Sébastien; Tsamados, Michel; Tseng, Kuo-hsin; Ubelmann, Clément; Uebbing, Bernd; Vergara, Oscar; Verron, Jacques; Vieira, Telmo; Vignudelli, Stefano; Vinogradova Shiffer, Nadya; Visser, Pieter; Vivier, Frederic; Volkov, Denis; Von Schuckmann, Karina; Vuglinskii, Valerii; Vuilleumier, Pierrik; Walter, Blake; Wang, Jida; Wang, Chao; Watson, Christopher; Wilkin, John; Willis, Josh; Wilson, Hilary; Woodworth, Philip; Yang, Kehan; Yao, Fangfang; Zaharia, Raymond; Zakharova, Elena; Zaron, Edward D.; Zhang, Yongsheng; Zhao, Zhongxiang; Zinchenko, Vadim; Zlotnicki, Victor. |
| In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and... |
| Tipo: Text |
Palavras-chave: Satellite altimetry; Oceanography; Sea level; Coastal oceanography; Cryospheric sciences; Hydrology. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/79999/82978.pdf |
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| Legrand, P; Schrama, Ejo; Tournadre, Jean. |
| The mean dynamic topography of the surface of the ocean is estimated using a finite difference inverse model of the ocean circulation constrained by a prior TOPEX/Poseidon-EGM96 estimate and an ocean density climatology. The EGM96 geoid uncertainties are represented by their full covariance matrix. The model finds a solution that yields a new 1°-resolution dynamic topography estimate with a 5 cm precision. The existence of this solution suggests that the uncertainties in EGM96, despite being much smaller than in previous geopotential models, are nonetheless realistic. The geodetic information constrains the inverse estimate of the ocean circulation, particularly at high latitudes. |
| Tipo: Text |
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| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/2003/publication-361.pdf |
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| Matsumoto, Haru; Bohnenstiehl, Delwayne R.; Tournadre, Jean; Dziak, Robert P.; Haxel, Joseph H.; Lau, T. -k. A.; Fowler, Matt; Salo, Sigrid A.. |
| In late 2007, two massive icebergs, C19a and B15a, drifted into open water and slowly disintegrated in the southernmost Pacific Ocean. Archived acoustic records show that the high-intensity underwater sounds accompanying this breakup increased ocean noise levels at mid-to-equatorial latitudes over a period of ∼1.5 years. More typically, seasonal variations in ocean noise, which are characterized by austral summer-highs and winter-lows, appear to be modulated by the annual cycle of Antarctic iceberg drift and subsequent disintegration. This seasonal pattern is observed in all three Oceans of the Southern Hemisphere. The life cycle of Antarctic icebergs affects not only marine ecosystem but also the sound environment in far-reaching areas and must be... |
| Tipo: Text |
Palavras-chave: Antarctica; Iceberg; Ocean noise; Seasonality; Trend. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00205/31613/30035.pdf |
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| Tournadre, Jean; Bouhier, Nicolas; Girard-ardhuin, Fanny; Remy, F.. |
| Basal melting of floating ice shelves and iceberg calving constitute the two almost equal paths of freshwater flux between the Antarctic ice cap and the Southern Ocean. The largest icebergs (>100 km2) transport most of the ice volume but their basal melting is small compared to their breaking into smaller icebergs that constitute thus the major vector of freshwater. The archives of nine altimeters have been processed to create a database of small icebergs (<8 km2) within open water containing the positions, sizes, and volumes spanning the 1992–2014 period. The intercalibrated monthly ice volumes from the different altimeters have been merged in a homogeneous 23 year climatology. The iceberg size distribution, covering the 0.1–10,000 km2 range,... |
| Tipo: Text |
Palavras-chave: Iceberg; Altimetry; Southern Ocean. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00307/41863/41114.pdf |
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| 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 |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19444/17050.pdf |
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| Tournadre, Jean. |
| Marine ecosystems are under increasing anthropogenic pressures from marine and terrestrial activities. Ship traffic, the major cause of change in the open ocean, and its temporal evolution are still largely unknown because of lack of data. Altimeter data provide a new powerful tool to detect and monitor the ship traffic through a method of analysis of echo waveform. The archive of seven altimeter missions has been processed to create a two decade database of ship locations. The estimated annual density maps compare well with the ones obtained from Automatic Identification System. The ship traffic analysis shows a global fourfold growth between 1992 and 2012, the largest increase being observed in the Indian Ocean and the Chinese seas reflecting the world... |
| Tipo: Text |
Palavras-chave: Altimetry; Ship traffic; Pollution; Anthropogenic pressure. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00229/34039/32432.pdf |
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| Tournadre, Jean; Lambin, J; Steunou, N. |
| The AltiKa project developed by the French Centre National d'Etudes Spatiales is based on a wide-band Ka-band altimeter (35.75 GHz). The technical characteristic of the instrument will offer higher performance both in terms of spatial and vertical resolution that will lead to improved observation of ice, coastal areas, inland waters and wave height. An Indian Space Research Organization satellite, Saral will embark the AltiKa altimeter. The launch is scheduled at the end of 2010. The major drawback of Ka band use is the attenuation of the radar signal by atmospheric liquid water. Clouds and rain effects will thus be a strong constraining factor, because the altimeter link budget imposes an attenuation of less than 3 dB. The impact of rain and clouds on... |
| Tipo: Text |
Palavras-chave: Geophysical parameters estimates; Rain and cloud impact; Ka band altimeter. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4720.pdf |
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| Tournadre, Jean; Lambin, J; Steunou, N. |
| The main instrument of the French-Indian Altika/ SARAL mission scheduled for launch in 2010, is the Kaband Altika altimeter. The high attenuation due to atmospheric water (liquid or vapor) at this frequency band is the major drawback of the use of Ka-band. In part I of this paper, the impact of rain/clouds on Ka-band data and on the accuracy of the estimates of the geophysical parameters have been analyzed and quantified using an analytical model of waveform. Waveform distortion and errors on the geophysical parameters can be significant especially for small dense clouds and rain cells. It is thus necessary to flag the data potentially affected by rain and clouds. The use of a single channel for Altika prevents the use of the classical dual-frequency rain... |
| Tipo: Text |
Palavras-chave: Rain/cloud flag; Rain and cloud impact; Ka band altimeter. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4721.pdf |
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| Von Schuckmann, Karina; Le Traon, Pierre-yves; Smith, Neville; Pascual, Ananda; Djavidnia, Samuel; Gattuso, Jean-pierre; Grégoire, Marilaure; Nolan, Glenn; Aaboe, Signe; Fanjul, Enrique Álvarez; Aouf, Lotfi; Aznar, Roland; Badewien, T. H.; Behrens, Arno; Berta, Maristella; Bertino, Laurent; Blackford, Jeremy; Bolzon, Giorgio; Borile, Federica; Bretagnon, Marine; Brewin, Robert J.w.; Canu, Donata; Cessi, Paola; Ciavatta, Stefano; Chapron, Bertrand; Trang Chau, Thi Tuyet; Chevallier, Frédéric; Chtirkova, Boriana; Ciliberti, Stefania; Clark, James R.; Clementi, Emanuela; Combot, Clement; Comerma, Eric; Conchon, Anna; Coppini, Giovanni; Corgnati, Lorenzo; Cossarini, Gianpiero; Cravatte, Sophie; De Alfonso, Marta; De Boyer Montégut, Clement; De Lera Fernández, Christian; De Los Santos, Francisco Javier; Denvil-sommer, Anna; De Pascual Collar, Álvaro; Dias Nunes, Paulo Alonso Lourenco; Di Biagio, Valeria; Drudi, Massimiliano; Embury, Owen; Falco, Pierpaolo; D’andon, Odile Fanton; Ferrer, Luis; Ford, David; Freund, H.; León, Manuel Garcia; Sotillo, Marcos García; García-valdecasas, José María; Garnesson, Philippe; Garric, Gilles; Gasparin, Florent; Gehlen, Marion; Genua-olmedo, Ana; Geyer, Gerhard; Ghermandi, Andrea; Good, Simon A.; Gourrion, Jerome; Greiner, Eric; Griffa, Annalisa; González, Marcelo; Griffa, Annalisa; Hernández-carrasco, Ismael; Isoard, Stéphane; Kennedy, John J.; Kay, Susan; Korosov, Anton; Laanemäe, Kaari; Land, Peter E.; Lavergne, Thomas; Lazzari, Paolo; Legeais, Jean Francois; Lemieux, Benedicte; Levier, Bruno; Llovel, William; Lyubartsev, Vladyslav; Lien, Vidar S.; Lima, Leonardo; Lorente, Pablo; Mader, Julien; Magaldi, Marcello G.; Maljutenko, Ilja; Mangin, Antoine; Mantovani, Carlo; Marinova, Veselka; Masina, Simona; Mauri, Elena; Meyerjürgens, J.; Mignot, Alexandre; Mcewan, Robert; Mejia, Carlos; Melet, Angélique; Menna, Milena; Meyssignac, Benoît; Mouche, Alexis; Mourre, Baptiste; Müller, Malte; Notarstefano, Giulio; Orfila, Alejandro; Pardo, Silvia; Peneva, Elisaveta; Pérez-gómez, Begoña; Perruche, Coralie; Peterlin, Monika; Poulain, Pierre-marie; Pinardi, Nadia; Quilfen, Yves; Raudsepp, Urmas; Renshaw, Richard; Révelard, Adèle; Reyes-reyes, Emma; Ricker, M.; Rodríguez-rubio, Pablo; Rotllán, Paz; Gelabert, Eva Royo; Rubio, Anna; Ruiz-parrado, Inmaculada; Sathyendranath, Shubha; She, Jun; Solidoro, Cosimo; Stanev, Emil V.; Staneva, Joanna; Storto, Andrea; Su, Jian; Bakhsh, Tayebeh Tajalli; Tilstone, Gavin H.; Tintoré, Joaquín; Toledano, Cristina; Tournadre, Jean; Tranchant, Benoit; Uiboupin, Rivo; Valcarcel, Arnaud; Valcheva, Nadezhda; Verbrugge, Nathalie; Vrac, Mathieu; Wolff, J.-o.; Zambianchi, Enrico; Zielinski, O.; Zinck, Ann-sofie; Zunino, Serena. |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00653/76554/77672.pdf |
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| Reul, Nicolas; Saux Picart, Stephane; Chapron, Bertrand; Vandemark, D.; Tournadre, Jean; Salisbury, J.. |
| Microwave Sea Surface Salinity (SSS) measurements can be performed by isolating the emissivity response to salinity changes from numerous geophysical effects, including surface temperature and wind waves. At L-band frequencies (1 to 2 GHz), the sensitivity to SSS is sufficient but it falls off quickly as frequency is increased. Nevertheless, methods using higher microwave frequencies with much lower SSS sensitivity than at L band, can already be tested. In particular, combining 6 and 10 GHz data in vertical polarization efficiently minimizes sea surface roughness and thermal impacts. Using AMSR-E data, the retrieved bi-monthly maps of SSS at 0.5 degrees resolution over the region of the Amazon plume show relative accuracy in-line with the future L-band... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6620.pdf |
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| Tournadre, Jean. |
| Radar meteorologists have estimated, over a number of years, rainfall rate with ground-based radars. Since the 1970s, use of weather radar as an active technique to measure rainfall from space has been proposed, and a number of radar concepts, including modified radar altimeter design, were proposed. However, no attempt has yet been made to determine rain cell characteristics from available altimeter data. This paper presents a method to estimate rainfall rate and rain cell diameter from TOPEX/Poseidon dual frequency radar altimeter waveforms. The rain-affected waveforms are first selected using a criterion based on a departure from a normal Ku-C-band backscatter coefficient relationship and on a threshold of liquid water content estimated by the TOPEX... |
| Tipo: Text |
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| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00448/55941/57483.pdf |
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| Chen, Ge; Chapron, Bertrand; Tournadre, Jean; Katsaros, Kristina; Vandemark, Douglas. |
| The TOPEX/POSEIDON mission offers the first opportunity to observe rain cells over the ocean by a dual-frequency radar altimeter (TOPEX) and simultaneously observe their natural radiative properties by a three-frequency radiometer (TOPEX microwave radiometer (TMR)). This work is a feasibility study aimed at understanding the capability and potential of the active/passive TOPEX/TMR system for oceanic rainfall detection. On the basis of past experiences in rain flagging, a joint TOPEX/TMR rain probability index is proposed. This index integrates several advantages of the two sensors and provides a more reliable rain estimate than the radiometer alone. One year's TOPEX/TMR TMR data are used to test the performance of the index. The resulting rain frequency... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00336/44719/44883.pdf |
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| Tournadre, Jean; Whitmer, K; Ardhuin, Fanny. |
| Small icebergs (edge lengths <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 |
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| Tournadre, Jean; Quilfen, Yves. |
| [1] The two scatterometers currently in operation, the Ku-band NASA Seawinds on the QuikScat satellite and the C-band AMI-Wind on the ERS-2 satellite, are designed to infer the ocean wind vectors from sea surface radar backscatter measurements. They provide excellent coverage of the ocean, and their wind products are of great value for ocean and meteorological communities. However, the presence of rain within scatterometer cells can significantly modify the sea surface backscatter coefficient and hence alter the wind vector retrieval. These perturbations can hamper the analysis of wind fields within atmospheric low-pressure systems or tropical cyclones. Rain perturbations result from volume scattering and attenuation by raindrops in the atmosphere as well... |
| Tipo: Text |
Palavras-chave: Model of interaction; Ocean surface winds; Rain; Scatterometer. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-513.pdf |
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| Tournadre, Jean; Quilfen, Yves. |
| In October and early November 1999, the GOGP99 experiment collected hydrological, currentmeter, tide recorder, thermistor and drifting buoy data near the Strait of Hormuz. Data analysis provides the water mass structure in the Strait: Persian Gulf Water (PGW) core is banked against the Omani coast, while Indian Ocean Surface Water (IOSW) lies near the Iranian coast. These water masses are most often covered by a homogeneous surface layer. Thermohaline characteristics of the PGW core decrease substantially downstream, from the Persian/Arabian Gulf to the Gulf of Oman. PGW and IOSW thermohaline characteristics and distribution also exhibit notable changes at periods shorter than a month as shown by repeated hydrological sections. The tidal signal measured... |
| Tipo: Text |
Palavras-chave: Wind retrieval; Rain; Scatterometer. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-388.pdf |
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| Registros recuperados: 39 | |
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