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| Registros recuperados: 107 | |
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| Bouruet-aubertot, Pascale; Mercier, Herle; Gaillard, Fabienne; Lherminier, Pascale. |
| The purpose of this paper is to characterize inertia-gravity waves (IGW) activity and to investigate the variability of these waves in relationship to atmospheric forcing and larger-scale motions. To this aim, we analyzed Eulerian measurements of horizontal currents and temperature collected over 1 year during the Programme Océan Multidisciplinaire Méso Echelle (POMME). We focused on the main frequency components of the IGW spectrum, namely the inertial frequency f and the semidiurnal frequency M2. Time evolution of the relative energy of these two components gave evidence of isolated events of high intensity. We performed a detailed analysis of these events and identified mechanisms of generation of these waves. Localized spots of intense, near-inertial... |
| Tipo: Text |
Palavras-chave: Turbulent mixing; Tnertia gravity waves. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-359.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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| Mercier, Herle. |
| L'océan est mis en mouvement par deux moteurs: l'action du vent et les flux de chaleur à l'interface air-mer. Les études consacrées à la compréhension de la réponse de l'océan au forçage du vent, le premier moteur, ont été ces dernières décennies, avec succès, au centre des préoccupations des océanographes, Aux moyennes latitudes, les modèles numériques forcés par le vent reproduisent les courants de frontière Ouest tels que le Gulf Stream et, si la résolution spatiale est suffisante, les instabilités génèrent des structures tourbillonnaires qui sont semblables à celles observées dans l'océan réel et qui, bien que d'échelle spatiale plus petite, sont l'analogue des dépressions atmosphériques. C'est la prise de conscience que, dans l'océan, les transferts... |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/1993/publication-7454.pdf |
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| Mercier, Herle; Lherminier, Pascale; Gourcuff, Claire. |
| The OVIDE project studies the variability of the north Atlantic subbpolar gyre circulation based on repeated hydrography and current measurements, satellite observations, diagnostic and prognostic models. Here, we present an analysis of volume and heat transports between Greenland and Portugal from the 2002 OVIDE data. The results are compared to a previous analysis based on 1997 data (4x project). We focus on the thermohaline circulation. The thermohaline circulation, deep western boundary current and heat flux variability are correlated. |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6102.pdf |
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| Feucher, Charlene; Maze, Guillaume; Mercier, Herle. |
| In the north Atlantic subtropical gyre, the oceanic vertical structure of density is characterized by a region of rapid increase with depth. This layer is called the permanent pycnocline. The permanent pycnocline is found below a surface mode water ,which are ventilated every winter when penetrated locally by the mixed layer. Assessing the structure and variability of the permanent pycnocline is of a major interest in the understanding of the climate system because the pycnocline layer delimits important heat and anthropogenic reservoir. Moreover, the heat content structure translate into changes in the large scale stratification feature, such as the permanent pycnocline. We developed a new objective algorithm for the characterization of the large scale... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00318/42870/42351.pdf |
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| Perez, Fiz F; Fontela, Marcos; Garcia-ibanez, Maria Isabel; Mercier, Herle; Velo, Anton; Lherminier, Pascale; Zunino, Patricia; De La Paz, Mercedes; Alonso-perez, Fernando; Guallart, Elisa E.; Padin, Xose A.. |
| Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO2) and experiencing ocean acidification1, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the ‘aragonite saturation horizon’—below which waters are undersaturated with respect to a particular calcium carbonate, aragonite—to move to shallower depths (to shoal), exposing corals to corrosive waters2,3. Here we use a database analysis to show that the present rate of supply of acidified waters to the deep Atlantic could cause the aragonite saturation horizon to shoal by 1,000–1,700 metres in the subpolar North Atlantic within the next three... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00426/53783/55106.pdf |
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| Le Traon, Pierre-yves; D'Ortenzio, Fabrizio; Babin, Marcel; Leymarie, Edouard; Marec, Claudie; Pouliquen, Sylvie; Thierry, Virginie; Cabanes, Cecile; Claustre, Hervé; Desbruyeres, Damien; Lacour, Leo; Lagunas, Jose-luis; Maze, Guillaume; Mercier, Herle; Penkerc'H, Christophe; Poffa, Noe; Poteau, Antoine; Prieur, Louis; Racape, Virginie; Randelhoff, Achim; Rehm, Eric; Schmechtig, Catherine Marie; Taillandier, Vincent; Wagener, Thibaut; Xing, Xiaogang. |
| Argo, the international array of profiling floats, is a major component of the global ocean and climate observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of the French “Investissements d’Avenir” Equipex program. The objectives of NAOS were to consolidate the French contribution to Argo’s core mission (global temperature and salinity measurements down to 2000 m), and also to develop the future generation of French Argo profiling floats and prepare the next phase of the Argo program with an extension to the deep ocean (Deep Argo), biogeochemistry (BGC-Argo) and polar seas. This paper summarizes how NAOS has met its objectives. The project significantly boosted France’s contribution to Argo’s core mission by... |
| Tipo: Text |
Palavras-chave: Profiling floats; Deep ocean; Biogeochemistry; Mediterranean Sea; Arctic; Atlantic; Argo. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76584/77729.pdf |
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| Sarafanov, Artem; Falina, Anastasia; Mercier, Herle; Sokov, Alexey; Lherminier, Pascale; Gourcuff, Claire; Gladyshev, Sergey; Gaillard, Fabienne; Daniault, Nathalie. |
| A mean state of the full-depth summer circulation in the Atlantic Ocean in the region in between Cape Farewell (Greenland), Scotland and the Greenland-Scotland Ridge (GSR) is assessed by combining 2002–2008 yearly hydrographic measurements at 59.5°N, mean dynamic topography, satellite altimetry data and available estimates of the Atlantic–Nordic Seas exchange. The mean absolute transports by the upper-ocean, mid-depth and deep currents and the Meridional Overturning Circulation (MOCσ = 16.5 ± 2.2 Sv, at σ0 = 27.55) at 59.5°N are quantified in the density space. Inter-basin and diapycnal volume fluxes in between the 59.5°N section and the GSR are then estimated from a box model. The dominant components of the meridional exchange across 59.5°N are the North... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00059/16997/14499.pdf |
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| De Boisseson, Eric; Thierry, Virginie; Mercier, Herle; Caniaux, G.. |
| The mixed layer processes that govern the mode water properties in the Iceland Basin are quantified through a mixed layer heat budget from Argo data collected over 2001-2007. This budget includes the mixed layer heat content variation, the surface heat fluxes, and the Ekman contribution to advection. The geostrophic advection cannot be directly estimated from Argo data but, following previous works, an ad hoc procedure is implemented to take it into account. The resulting annual budget is closed within the error bar but this closure hides some compensation between the summer and the winter residuals (-16 +/- 9 W m(-2) and 21 +/- 26 W m(-2), respectively). A similar heat budget built by using colocated Argo floats in the 1/4 degrees DRAKKAR ORCA025-G70fo... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00017/12807/9761.pdf |
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| Puillat, Ingrid; Prevosto, Marc; Mercier, Herle; Thomas, S.. |
| In our time emerged the idea of a major environmental degradation, at both local and global scales, in the face of the recurrent human pollution. Consequently in the sake of a sustainable humanity development, of the ethic and of the ecology, the protection and the monitoring of our environment have become a major stake. Many scientific and technical tools contributed to improve the environmental knowledge, as helped remote and in situ observations, and forecast modeling. In situ environmental sensor systems have been designed to be increasingly sustainable even in a hostile environment such as the deep ocean. In a similar way, the infrastructures hosting those sensors are now thought and built to be permanent. In marine sciences these considerations gave... |
| Tipo: Text |
Palavras-chave: Time series; Marine data; Signal processing; Statistics. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00161/27259/25468.pdf |
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| Maze, Guillaume; Thierry-theetten, Virginie; Mercier, Herle. |
| At mid-latitudes, the oceanic vertical structure of density is characterized by a permanent highly stratified layer: the pycnocline. The pycnocline is the transition layer between surface water masses ventilated every winter when penetrated locally by the mixed layer and deeper water masses which have been ventilated at high latitudes and circulate equatorward. The pycnocline thus reflects a large scale balance between the penetration of local air-sea interactions and the re-emergence of remote ones. The overall question we want to address is whether and to which extent the variability of the pycnocline properties (depth, thickness and thermohaline characteristics) are influenced by those of air-sea interactions. To this end, we first developed a new... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00133/24435/22448.pdf |
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| Zunino Rodriguez, Patricia; Mercier, Herle; Thierry, Virginie. |
| After more than a decade of shallow convection, deep convection returned to the Irminger Sea in 2008 and occurred several times since then to reach exceptional convection depths (> 1500 m) in 2015 and 2016. Additionally, deep mixed layers deeper than 1600 m were also reported southeast of Cape Farewell in 2015. In this context, we used Argo data to show that deep convection occurred southeast of Cape Farewell (SECF) in 2016 and persisted during two additional years in 2017 and 2018 with a maximum convection depth deeper than 1300 m. In this article, we investigate the respective roles of air-sea buoyancy flux and preconditioning of the water column (ocean interior buoyancy content) to explain this 4-year persistence of deep convection SECF. We analyzed... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71776/70265.pdf |
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| Garcia-ibanez, Maria Isabel; Zunino, Patricia; Frob, Friederike; Carracedo, Lidia I.; Rios, Aida F.; Mercier, Herle; Olsen, Are; Perez, Fiz F. |
| Repeated hydrographic sections provide critically needed data on and understanding of changes in basin-wide ocean CO2 chemistry over multi-decadal timescales. Here, high-quality measurements collected at twelve cruises carried out along the same track between 1991 and 2015 have been used to determine long-term changes in ocean CO2 chemistry and ocean acidification in the Irminger and Iceland basins of the North Atlantic Ocean. Trends were determined for each of the main water masses present and are discussed in the context of the basin-wide circulation. The pH has decreased in all water masses of the Irminger and Iceland basins over the past 25 years with the greatest changes in surface and intermediate waters (between −0.0010 ± 0.0001 and −0.0018 ± 0.0001... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00343/45443/44968.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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| Ganachaud, Alexandre; Mercier, Herle. |
| [1] Wind friction at the ocean surface introduces energetic variations in the net mass transport across the oceanic basins. To conserve mass, the whole water column adjusts rapidly, introducing a depth-independent perturbation in the pressure field. This signal is analyzed in a high resolution numerical model of the Atlantic Ocean. While the pressure perturbation cannot be extracted from the energetic sea surface height signals, it represents up to 90% of the bottom pressure signal when integrated across the Atlantic Ocean in the daily and monthly frequencies. This signal will be an important part of the signal measured by the GRACE (Gravity Recovery And Climate Experiment) mission. |
| Tipo: Text |
Palavras-chave: Eckman transport; Numerical model; Pressure perturbation; Ocean surface. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-490.pdf |
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| Ferron, Bruno; Mercier, Herle; Speer, Kevin; Gargett, Ann; Polzin, Kurt. |
| The Romanche Fracture Zone is a major gap in the Mid-Atlantic Ridge at the equator, which is deep enough to allow significant eastward flows of Antarctic Bottom Water from the Brazil Basin to the Sierra Leone and Guinea Abyssal Plains. While flowing through the Romanche Fracture Zone, bottom-water properties are strongly modified due to intense vertical mixing. The diapycnal mixing coefficient in the bottom water of the Romanche Fracture Zone is estimated by using the finestructure of CTD profiles, the microstructure of high-resolution profiler data, and by constructing a heat budget from current meter data. The finestructure of density profiles is described using the Thorpe scales L-T. It is shown from microstructure data taken in the bottom water that... |
| Tipo: Text |
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| Ano: 1998 |
URL: https://archimer.ifremer.fr/doc/00447/55830/62131.pdf |
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| Mercier, Herle; Billant, Andre; Branellec, Pierre; Gouillou, Jean-pierre; Hemon, Catherine; Lagadec, Catherine. |
| La campagne Romanche 3 s'est déroulée du 27 octobre au 15 novembre 1994, de Dakar (Sénégal) à Dakar, à bord du navire de recherche de l'IFREMER Le Noroît. Romanche 3, troisième campagne dans le cadre du projet Romanche, avait pour but le relevage des mouillages de courantométrie mis à l'eau en novembre 1992 dans les zones de fracture de l'Atlantique équatorial Romanche et Chain. Cela a aussi été l'occasion de compléter la description de l'hydrologie des zones de fracture en effectuant 29 stations CTD. Le châssis CTD était équipé d'un ADCP 150 kHz ce qui a permis de réaliser des mesures de courant, de la surface au fond, à 26 des 29 stations CTD (technique du LADCP). Le projet Romanche fait partie de l'expérience Deep Basin Experiment (DBE) du core 3 de... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00233/34430/32853.pdf |
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| Ferron, Bruno; Mercier, Herle; Treguier, Anne-marie. |
| This paper investigates the dynamics of the Antarctic Bottom Water (AABW) flow through the Romanche Fracture Zone (RFZ) in a primitive equation model with a high horizontal and vertical resolution. Two examples of Rows over simple bathymetries show that a reduced gravity model captures the essential dynamics of the primitive equation model. The reduced gravity model is then used as a tool to identify what are the bathymetric structures (sills, narrows) that mostly constrain the AABW flow through the RFZ. When only these structures are represented in the primitive equation model, the AABW how is shown to be coherent with observations (transports, density and velocity structures). |
| Tipo: Text |
Palavras-chave: Circulation model; Fracture zone; Bottom water; Bathymetry. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-802.pdf |
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| Maze, Guillaume; Mercier, Herle; Fablet, Ronan; Lenca, Philippe; Piolle, Jean-francois. |
| Les bases de données marines, alimentées par les satellites et les robots autonomes sous-marins comme les flotteurs du réseau Argo, sont de plus en plus grandes (plusieurs dizaines de gigaoctets et teraoctets) et rapidement évolutives (elles changent d’heure en heure). Cette augmentation spectaculaire de la dimension et de la complexité des données rend difficile leur exploitation avec les outils standards. Or, c’est à partir de l’analyse des données que les chercheurs pourront réaliser de nouvelles découvertes scientifiques sur la dynamique des océans, à grande et petite échelles, et les changements climatiques régionaux et globaux. L'école d’été OBIDAM14 visait à contribuer à lever ces verrous d’analyse en introduisant les méthodes de fouille de données... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00216/32710/31075.pdf |
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| Mercier, Herle; Billant, Andre; Branellec, Pierre; Andrie, Chantal; Messias, Marie-josé; Gouriou, Yves; Lagadec, Catherine. |
| La campagne Romanche 2 s'est déroulée du 12 novembre au 2 décembre 1992, de Dakar (Sénégal) à Douala (Cameroun), à bord du navire de recherche de l'Ifremer L'Atalante. Romanche 2, deuxième campagne dans le cadre du projet Romanche, avait pour but la mise à l'eau de huit mouillages de courantométrie dans les zones de fracture de l'Atlantique équatorial Romanche et Chain. Cela a été l'occasion de compléter la description de l'hydrologie de ces zones de fracture, initiée lors de la campagne Romanche1 (Mercier et al., Campagne Romanche1, Données CTDO2, Chimie et Bathymétrie, rapport interne LPO, 92-02). Vingt cinq stations d'hydrologie et de géochimie ont été effectuées. Les mouillages mis à l'eau en 1992 ont été relevés en novembre 1994. Les données de... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00233/34426/32842.pdf |
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| Registros recuperados: 107 | |
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