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| Registros recuperados: 107 | |
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| Ferron, Bruno; Kokoszka, Florian; Mercier, Herle; Lherminier, Pascale; Huck, Thierry; Rios, Aida; Thierry, Virginie. |
| The variability of the turbulent kinetic energy dissipation due to internal waves is quantified using a finescale parameterisation applied to the A25 Greenland-Portugal transect repeated every two years from 2002 to 2012. The internal wave velocity shear and strain are estimated for each cruise at 91 stations from full depth vertical profiles of density and velocity. The 2002–2012 averaged dissipation rate, <ε2002–2012>, in the upper ocean lies in the range 1–10 × 10-10 W kg-1. At depth, <ε2002–2012> is smaller than 1 × 10-10 W kg-1 except over rough topography found at the continental slopes, the Reykjanes Ridge and in a region delimited by the Azores-Biscay Rise and Eriador Seamount. There, the vertical energy flux of internal waves is... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44463/44141.pdf |
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| Zunino Rodriguez, Patricia; Perez, Fiz F.; Lherminier, Pascale; Mercier, Herle. |
| The highest anthropogenic CO2 (Cant) inventories of all the oceans are found in the subpolar North Atlantic (SPNA). The OVIDE section crosses the SPNA from Greenland to Portugal and is repeated biennially since 2002. Therefore, OVIDE data allow evaluating the evolution of inventories of anthropogenic CO2 (Cant) in the SPNA. This oceanic region is known to host water formation and ventilation processes that change the water mass volumetric census year by year. Changes in the volumetric census cause differences in the Cant inventory estimates (Pérez et al., 2008). Consequently, Pérez et al. (2010) proposed a method for computing Cant inventory in the SPNA taking into account the volumetric census variability and a bathymetric adjustment. This method has been... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00270/38170/36314.pdf |
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| Petit, Tillys; Mercier, Herle; Thierry, Virginie. |
| The Reykjanes Ridge strongly influences the circulation of the North Atlantic Subpolar Gyre as it flows to the Irminger Sea from the Iceland Basin. The circulation is composed of two main along‐ridge currents: the southwestward East Reykjanes Ridge Current (ERRC) in the Iceland Basin and the northeastward Irminger Current (IC) in the Irminger Sea. To study their interconnection through the ridge, as well as their connections with the interior of each basin, velocity and hydrological measurements were carried out along and perpendicular to the crest of the Reykjanes Ridge in June–July 2015 as part of the RREX project. This new dataset changes our view of the ERRC and IC as it reveals undocumented along‐stream evolutions of their hydrological properties,... |
| Tipo: Text |
Palavras-chave: North-Atlantic Subpolar Gyre; Bathymetry; Oceanic circulation; Observations. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00591/70347/68407.pdf |
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| Zunino, Patricia; Lherminier, Pascale; Mercier, Herle; Padin, Xose A.; Rios, Aida F.; Perez, Fiz F.. |
| The subpolar North Atlantic (SPNA) is important in the global carbon cycle because of the deep water ventilation processes that lead to both high uptake of atmospheric CO2 and large inventories of anthropogenic CO2 (C-ant). Thus, it is crucial to understand its response to increasing anthropogenic pressures. In this work, the budgets of dissolved inorganic carbon (DIC), C-ant and natural DIC (DICnat) in the eastern SPNA in the 2000s, are jointly analyzed using in situ data. The DICnat budget is found to be in steady state, confirming a long-standing hypothesis from in situ data for the first time. The biological activity is driving the uptake of natural CO2 from the atmosphere. The C-ant increase in the ocean is solely responsible of the DIC storage rate... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00313/42419/41756.pdf |
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| Le Traon, Pierre-yves; Mercier, Herle. |
| The non-linear inverse model described in Mercier et al. (1992) is used to estimate the mean surface topography of the North Atlantic and its formal error. The surface is based on a large hydrographic and Lagrangian data set and has spatial resolution of 2-degrees in latitude by 2.5-degrees in longitude. The formal error is between 4 and 8 cm. Contrary to previous estimations, this takes into account the errors with regard both to the density field and to the estimation of the velocity field at a reference level. |
| Tipo: Text |
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| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00079/18977/17955.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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| Lozier, M. Susan; Bacon, Sheldon; Bower, Amy S.; Cunningham, Stuart A.; De Jong, M. Femke; De Steur, Laura; Deyoung, Brad; Fischer, Juergen; Gary, Stefan F.; Greenan, Blair J. W.; Heimbach, Patrick; Holliday, Naomi P.; Houpert, Loic; Inall, Mark E.; Johns, William E.; Johnson, Helen L.; Karstensen, Johannes; Li, Feili; Lin, Xiaopei; Mackay, Neill; Marshall, David P.; Mercier, Herle; Myers, Paul G.; Pickart, Robert S.; Pillar, Helen R.; Straneo, Fiammetta; Thierry, Virginie; Weller, Robert A.; Williams, Richard G.; Wilson, Chris; Yang, Jiayan; Zhao, Jian; Zika, Jan D.. |
| A new ocean observing system has been launched in the North Atlantic in order to understand the linkage between the meridional overturning circulation and deep water formation. For decades oceanographers have understood the Atlantic Meridional Overturning Circulation (AMOC) to be primarily driven by changes in the production of deep water formation in the subpolar and subarctic North Atlantic. Indeed, current IPCC projections of an AMOC slowdown in the 21st century based on climate models are attributed to the inhibition of deep convection in the North Atlantic. However, observational evidence for this linkage has been elusive: there has been no clear demonstration of AMOC variability in response to changes in deep water formation. The motivation for... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00358/46881/46764.pdf |
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| Garcia-ibanez, Maria Isabel; Perez, Fiz F.; Lherminier, Pascale; Zunino, Patricia; Mercier, Herle; Treguer, Paul. |
| We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended Optimum MultiParameter (eOMP) analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW) dominated the upper part of the GEOTRACES-GA01 section in 2014. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland–Scotland Overflow Water (ISOW) and North East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00412/52307/53112.pdf |
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| Sarthou, Geraldine; Lherminier, Pascale; Achterberg, Eric P.; Alonso-perez, Fernando; Bucciarelli, Eva; Boutorh, Julia; Bouvier, Vincent; Boyle, Edward A.; Branellec, Pierre; Carracedo, Lidia I.; Casacuberta, Nuria; Castrillejo, Maxi; Cheize, Marie; Pereira, Leonardo Contreira; Cossa, Daniel; Daniault, Nathalie; De Saint-leger, Emmanuel; Dehairs, Frank; Deng, Feifei; De Gesincourt, Floriane Desprez; Devesa, Jeremy; Foliot, Lorna; Fonseca-batista, Debany; Gallinari, Morgane; Garcia-ibanez, Maribel I.; Gourain, Arthur; Grossteffan, Emilie; Hamon, Michel; Heimburger, Lars Eric; Henderson, Gideon M.; Jeandel, Catherine; Kermabon, Catherine; Lacan, Francois; Le Bot, Philippe; Le Goff, Manon; Le Roy, Emilie; Lefebvre, Alison; Leizour, Stephane; Lemaitre, Nolwenn; Masque, Pere; Menage, Olivier; Barraqueta, Jan-lukas Menzel; Mercier, Herle; Perault, Fabien; Perez, Fiz F; Planquette, Helene; Planchon, Frederic; Roukaerts, Arnout; Sanial, Virginie; Sauzede, Raphaelle; Schmechtig, Catherine; Shelley, Rachel U.; Stewart, Gillian; Sutton, Jill; Tang, Yi; Tisnerat-laborde, Nadine; Tonnard, Manon; Treguer, Paul; Van Beek, Pieter; Zurbrick, Cheryl M.; Zunino Rodriguez, Patricia. |
| The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_ issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue. |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00470/58178/60685.pdf |
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| Fontela, Marcos; Garcia-ibanez, Maria Isabel; Hansell, Dennis A.; Mercier, Herle; Perez, Fiz F. |
| The quantitative role of the Atlantic Meridional Overturning Circulation (AMOC) in dissolved organic carbon (DOC) export is evaluated by combining DOC measurements with observed water mass transports. In the eastern subpolar North Atlantic, both upper and lower limbs of the AMOC transport high-DOC waters. Deep water formation that connects the two limbs of the AMOC results in a high downward export of non-refractory DOC (197 Tg-C center dot yr(-1)). Subsequent remineralization in the lower limb of the AMOC, between subpolar and subtropical latitudes, consumes 72% of the DOC exported by the whole Atlantic Ocean. The contribution of DOC to the carbon sequestration in the North Atlantic Ocean (62 Tg-C center dot yr(-1)) is considerable and represents almost a... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00342/45298/44754.pdf |
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| Sarafanov, Artem; Falina, Anastasia; Mercier, Herle; Lherminier, Pascale; Sokov, Alexey. |
| Recent decadal changes (1955-2007) in the baroclinic transport (TBC) of the Deep Western Boundary Current (DWBC) carrying the Greenland-Scotland overflow-derived waters along the East Greenland slope are quantified from a set of hydrographic sections in vicinity of Cape Farewell. The updated historical record of TBC shows clear decadal variability (+/- 2-2.5 Sv) with the transport minima in the 1950s and mid-1990s, maximum in the early 1980s and moderate-to-high transport in the 2000s. Since the mid-1990s, the DWBC TBC has increased by similar to 2 Sv (significant at the 99.9% level), which constitute similar to 20% of the mean absolute transport (9.0 Sv) as obtained from three cruises in 2002-2006. The DWBC TBC anomalies negatively correlate (R = -0.80)... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6633.pdf |
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| Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Le Traon, Pierre-yves. |
| A method to estimate mass and heat transports across hydrographic sections using hydrography together with altimetry data in a geostrophic box inverse model is presented. Absolute surface velocities computed from AVISO altimetry products made up of a combination of sea surface height measurements and geoid estimate are first compared to Ship Acoustic Doppler Current Profiler (S-ADCP) measurements of the Ovide project along hydrographic sections repeated every 2 years in summer from Portugal to Greenland. The rms difference between S-ADCP and altimetry velocities averaged on distances of about a hundred km accounts to 3.3 cm s−1. Considering that the uncertainty of S-ADCP velocities is found at 1.5 cm s−1, altimetry errors are estimated at 3 cm s−1.... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00038/14921/13751.pdf |
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| Billant, Andre; Branellec, Pierre; Mercier, Herle. |
| One of the key processes of the ocean circulation and large scale air-sea interaction is water mass formation. In the north Atlantic, the upper ocean circulation brings warm waters to higher latitudes, where vigorous cooling leads, during the winter, to the formation of deep mixed layers (up to several hundred meters deep). As these newly formed water masses are advected and spread southward they are overlaid during the spring and summer by warmer water. Thus they lose contact with the atmosphere and become part of ocean circulation as intermediate water. This succession of events constitute subduction. The newly formed water mass is typically of low potential vorticity (nearly homogeneous), with characteristics imparted by the local prevailing air sea... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00211/32201/30637.pdf |
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| Thierry, Virginie; De Boisseson, Eric; Mercier, Herle. |
| Combining hydrographic data from the OVIDE (Observatoire de la Variabilité Interannuelle à Decennale/Observatory of the Interannual to Decadal Variability) section (Greenland-Portugal) with Argo and historical CTD data over the period 19902006, we estimate the variability of the core properties of a variety of Subpolar Mode Water (SPMW) observed on the eastern flank of the Reykjanes Ridge. This SPMW acquires its core properties in the winter mixed layer along the eastern side of the Reykjanes Ridge. We find that the February sea surface temperature along the ridge is a proxy for its core temperature. The sources of this mode water are water masses advected by the mean cyclonic circulation in the Iceland Basin. A density compensated tendency for cooling... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Subpolar mode water; North Atlantic Ocean. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3487.pdf |
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| Carracedo Segade, Lidia Isabel; Gilcoto, Miguel; Mercier, Herle; Fernandez Perez, Fiz. |
| We describe the circulation patterns in the Azores–Gibraltar Strait region (North-Eastern Atlantic) during the 2009 CAIBOX cruise on the basis of hydrographic and direct current velocity measurements. This study offers new data for a region where importation of central waters (subpolar and subtropical modes of Eastern North Atlantic central waters) and exports of Mediterranean Water are strongly related to large-scale dynamics in the North Atlantic Ocean (Azores Current-Mediterranean Water system). The description is backed up quantitatively by the results of a box inverse model, which was used to obtain absolute water mass transport values consistent with thermal wind equations and with conservation of volume, salt and heat. The contributions of water... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00213/32383/30847.pdf |
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| Treguier, Anne-marie; Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Barnier, Bernard; Madec, Gurvan; Molines, Jean-marc; Penduff, Thierry; Czeschel, Lars; Boning, Claus. |
| Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of... |
| Tipo: Text |
Palavras-chave: Ocean model; Thermohaline circulation; North Atlantic; Climate variability; Oceanography. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2199.pdf |
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| Registros recuperados: 107 | |
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