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Frajka-williams, Eleanor; Ansorge, Isabelle J.; Baehr, Johanna; Bryden, Harry L.; Chidichimo, Maria Paz; Cunningham, Stuart A.; Danabasoglu, Gokhan; Dong, Shenfu; Donohue, Kathleen A.; Elipot, Shane; Heimbach, Patrick; Holliday, N. Penny; Hummels, Rebecca; Jackson, Laura C.; Karstensen, Johannes; Lankhorst, Matthias; Le Bras, Isabela A.; Lozier, M. Susan; Mcdonagh, Elaine L.; Meinen, Christopher S.; Mercier, Herle; Moat, Bengamin I.; Perez, Renellys C; Piecuch, Christopher G.; Rhein, Monika; Srokosz, Meric A.; Trenberth, Kevin E.; Bacon, Sheldon; Forget, Gael; Goni, Gustavo; Kieke, Dagmar; Koelling, Jannes; Lamont, Tarron; Mccarthy, Gerard D.; Mertens, Christian; Send, Uwe; Smeed, David A.; Speich, Sabrina; Van Den Berg, Marcel; Volkov, Denis; Wilson, Chris. |
The Atlantic Meridional Overturning Circulation (AMOC) extends from the Southern Ocean to the northern North Atlantic, transporting heat northwards throughout the South and North Atlantic, and sinking carbon and nutrients into the deep ocean. Climate models indicate that changes to the AMOC both herald and drive climate shifts. Intensive trans-basin AMOC observational systems have been put in place to continuously monitor meridional volume transport variability, and in some cases, heat, freshwater and carbon transport. These observational programs have been used to diagnose the magnitude and origins of transport variability, and to investigate impacts of variability on essential climate variables such as sea surface temperature, ocean heat content and... |
Tipo: Text |
Palavras-chave: Meridional overturning circulation; Thermohaline circulation; Observing systems; Ocean heat transport; Carbon storage; Moorings; Circulation variability. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61507/65342.pdf |
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Forget, Gael; Ferron, Bruno; Mercier, Herle. |
Argo is a global array of profiling floats that provides temperature (T) and salinity (S) profiles from 2000 m to the surface every ten days with a nominal spatial resolution of 3 degrees. Here we present idealized experiments where the adjoint method is used to synthesize simulated sets of Argo profiles with a general circulation model, over a one-year period, in the North Atlantic. Using a number of drifting profilers consistent with Argo deployment objectives, the simulated array permits one to identify large-scale anomalies in the hydrography and circulation, despite the presence of a simulated eddy noise of large amplitude. Model dynamics provide an objective means to distinguish eddy noise from large-scale oceanic variability, and to infer the... |
Tipo: Text |
Palavras-chave: General circulation model; Argo; Twin experiment; 4DVAR; Data assimilation. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3721.pdf |
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Forget, Gael; Mercier, Herle; Ferron, Bruno. |
A set of Argo profiles collected in the North Atlantic between May 2002 and April 2003 is combined with a low-resolution general circulation model (GCM) using the adjoint method. Fitting the real hydrographic observations leads to vast improvements in the model circulation., including the sea surface height and the meridional heat transport. We find striking differences in basin-scale transports compared with previous assimilation experiments that use the same GCM and a similar spatial resolution. Based on forward modeling studies, it is argued that these differences are due to different assimilation experiment durations. Over 1 year, the hydrography interpolated with the GCM from Argo profiles better represents the contemporary structures than does a... |
Tipo: Text |
Palavras-chave: General circulation model; Argo; In situ observations; 4DVAR; Data assimilation. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3920.pdf |
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Roquet, Fabien; Wunsch, Carl; Forget, Gael; Heimbach, Patrick; Guinet, Christophe; Reverdin, Gilles; Charrassin, Jean-benoit; Bailleul, Frederic; Costa, Daniel P.; Huckstadt, Luis A.; Goetz, Kimberly T.; Kovacs, Kit M.; Lydersen, Christian; Biuw, Martin; Nost, Ole A.; Bornemann, Horst; Ploetz, Joachim; Bester, Marthan N.; Mcintyre, Trevor; Muelbert, Monica C.; Hindell, Mark A.; Mcmahon, Clive R.; Williams, Guy; Harcourt, Robert; Field, Iain C.; Chafik, Leon; Nicholls, Keith W.; Boehme, Lars; Fedak, Mike A.. |
Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea... |
Tipo: Text |
Palavras-chave: Animal-borne sampling; Southern Ocean; State estimation; Hydrography. |
Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00241/35252/33765.pdf |
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Danabasoglu, Gokhan; Yeager, Steve G.; Bailey, David; Behrens, Erik; Bentsen, Mats; Bi, Daohua; Biastoch, Arne; Boening, Claus; Bozec, Alexandra; Canuto, Vittorio M.; Cassou, Christophe; Chassignet, Eric; Coward, Andrew C.; Danilov, Sergey; Diansky, Nikolay; Drange, Helge; Farneti, Riccardo; Fernandez, E; Fogli, Pier Giuseppe; Forget, Gael; Fujii, Yosuke; Griffies, Stephen M.; Gusev, Anatoly; Heimbach, Patrick; Howard, Armando; Jung, Thomas; Kelley, Maxwell; Large, William G.; Leboissetier, Anthony; Lu, Jianhua; Madec, G; Marsland, Simon J.; Masinam, Simona; Navarram, Antonio; Nurser, A. J. George; Pirani, Anna; Salas Y Melia, David; Samuels, Bonita L.; Scheinert, Markus; Sidorenko, Dmitry; Treguier, Anne-marie; Tsujino, Hiroyuki; Uotila, Petteri; Valcke, Sophie; Voldoire, Aurore; Wangi, Qiang. |
Simulation characteristics from eighteen global ocean–sea-ice coupled models are presented with a focus on the mean Atlantic meridional overturning circulation (AMOC) and other related fields in the North Atlantic. These experiments use inter-annually varying atmospheric forcing data sets for the 60-year period from 1948 to 2007 and are performed as contributions to the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II). The protocol for conducting such CORE-II experiments is summarized. Despite using the same atmospheric forcing, the solutions show significant differences. As most models also differ from available observations, biases in the Labrador Sea region in upper-ocean potential temperature and salinity distributions, mixed... |
Tipo: Text |
Palavras-chave: Global ocean-sea-ice modelling; Ocean model comparisons; Atmospheric forcing; Experimental design; Atlantic meridional overturning circulation; North Atlantic simulations. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00164/27525/28368.pdf |
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Roemmich, Dean; Alford, Matthew H.; Claustre, Hervé; Johnson, Kenneth; King, Brian; Moum, James; Oke, Peter; Owens, W. Brechner; Pouliquen, Sylvie; Purkey, Sarah; Scanderbeg, Megan; Suga, Toshio; Wijffels, Susan; Zilberman, Nathalie; Bakker, Dorothee; Baringer, Molly; Belbeoch, Mathieu; Bittig, Henry C.; Boss, Emmanuel; Calil, Paulo; Carse, Fiona; Carval, Thierry; Chai, Fei; Conchubhair, Diarmuid Ó.; D’ortenzio, Fabrizio; Dall’olmo, Giorgio; Desbruyeres, Damien; Fennel, Katja; Fer, Ilker; Ferrari, Raffaele; Forget, Gael; Freeland, Howard; Fujiki, Tetsuichi; Gehlen, Marion; Greenan, Blair; Hallberg, Robert; Hibiya, Toshiyuki; Hosoda, Shigeki; Jayne, Steven; Jochum, Markus; Johnson, Gregory C.; Kang, Kiryong; Kolodziejczyk, Nicolas; Körtzinger, Arne; Traon, Pierre-yves Le; Lenn, Yueng-djern; Maze, Guillaume; Mork, Kjell Arne; Morris, Tamaryn; Nagai, Takeyoshi; Nash, Jonathan; Garabato, Alberto Naveira; Olsen, Are; Pattabhi, Rama Rao; Prakash, Satya; Riser, Stephen; Schmechtig, Catherine; Schmid, Claudia; Shroyer, Emily; Sterl, Andreas; Sutton, Philip; Talley, Lynne; Tanhua, Toste; Thierry, Virginie; Thomalla, Sandy; Toole, John; Troisi, Ariel; Trull, Thomas W.; Turton, Jon; Velez-belchi, Pedro Joaquin; Walczowski, Waldemar; Wang, Haili; Wanninkhof, Rik; Waterhouse, Amy F.; Waterman, Stephanie; Watson, Andrew; Wilson, Cara; Wong, Annie P. S.; Xu, Jianping; Yasuda, Ichiro. |
The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i)... |
Tipo: Text |
Palavras-chave: Argo; Floats; Global; Ocean; Warming; Circulation; Temperature; Salinity. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00509/62043/66192.pdf |
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Balmaseda, M. A.; Hernandez, F.; Storto, A.; Palmer, M. D.; Alves, O.; Shi, L.; Smith, G. C.; Toyoda, T.; Valdivieso, M.; Barnier, B.; Behringer, D.; Boyer, T.; Chang, Y-s.; Chepurin, G. A.; Ferry, N.; Forget, Gael; Fujii, Y.; Good, S.; Guinehut, S.; Haines, K.; Ishikawa, Y.; Keeley, S.; Koehls, A.; Lee, T.; Martin, M. J.; Masina, S.; Masuda, S.; Meyssignac, B.; Mogensen, K.; Parent, L.; Peterson, K. A.; Tang, Y. M.; Yin, Y.; Vernieres, G.; Wang, X.; Waters, J.; Wedd, R.; Wang, O.; Xue, Y.; Chevallier, M.; Lemieux, J-f.; Dupont, F.; Kuragano, T.; Kamachi, M.; Awaji, T.; Caltabiano, A.; Wilmer-becker, K.; Gaillard, Fabienne. |
Uncertainty in ocean analysis methods and deficiencies in the observing system are major obstacles for the reliable reconstruction of the past ocean climate. The variety of existing ocean reanalyses is exploited in a multi-reanalysis ensemble to improve the ocean state estimation and to gauge uncertainty levels. The ensemble-based analysis of signal-to-noise ratio allows the identification of ocean characteristics for which the estimation is robust (such as tropical mixed-layer-depth, upper ocean heat content), and where large uncertainty exists (deep ocean, Southern Ocean, sea ice thickness, salinity), providing guidance for future enhancement of the observing and data assimilation systems. |
Tipo: Text |
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Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00280/39090/37655.pdf |
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Maze, Guillaume; Forget, Gael; Buckley, Martha; Marshall, John; Cerovecki, Ivana. |
The Walin water mass framework quantifies the rate at which water is transformed from one temperature class to another by air-sea heat fluxes (transformation). The divergence of the transformation rate yields the rate at which a given temperature range is created or destroyed by air-sea heat fluxes ( formation). Walin's framework provides a precise integral statement at the expense of losing spatial information. In this study the integrand of Walin's expression to yield transformation and formation maps is plotted and used to study the role of air-sea heat fluxes in the cycle of formation-destruction of the 18 degrees +/- 1 degrees C layer in the North Atlantic. Using remotely sensed sea surface temperatures and air-sea heat flux estimates based on both... |
Tipo: Text |
Palavras-chave: MASS FORMATION; TURBULENT FLUXES; OCEAN SURFACE; MODEL; VARIABILITY; RATES. |
Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00115/22647/20373.pdf |
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