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| Registros recuperados: 53 | |
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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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| Branellec, Pierre; Ferron, Bruno; Lherminier, Pascale. |
| La campagne Ovide 4, réalisée du 9 juin au 10 juillet 2008 sur le N/O Thalassa, est la quatrième d'une série de 5 campagnes océanographiques dont le but est d'établir un observatoire de la variabilité climatique du tourbillon subpolaire de l'océan Atlantique Nord. Le projet Ovide est dirigé par Herlé Mercier et il est principalement financé par Ifremer, INSU (LEFE-IDAO) et UBO. Les trois premières campagnes Ovide ont été réalisées à la même période de l'année en 2002, 2004, 2006 et le long du même trajet entre l'extrémité sud-est du Groenland et la Péninsule Ibérique (section Ovide, également appelée A25 dans le programme CLIVAR) via la Mer d'Irminger, le Bassin d'Islande et le Bassin Ouest Européen, légèrement au nord de la section FourEx d'août 1997... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00210/32124/30568.pdf |
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| Mccarthy, G.d.; Brown, P.j.; Flagg, C.n.; Goni, G.; Houpert, L.; Hughes, C.w.; Hummels, R.; Inall, M.; Jochumsen, K.; Larsen, K.m.h.; Lherminier, Pascale; Meinen, C.s.; Moat, B.i.; Rayner, D.; Rhein, M.; Roessler, A.; Schmid, C.; Smeed, D.a.. |
| The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of heat, freshwater, and carbon redistribution in the climate system. The precept that the AMOC has changed abruptly in the past, notably during and at the end of the last ice age, and that it is ‘very likely’ to weaken in the coming century due to anthropogenic climate change is a key motivation for sustained observations of the AMOC. This paper reviews the methodology and technology used to observe the AMOC and assesses these ideas and systems for accuracy, shortcomings, potential improvements and sustainability. We review hydrographic techniques and look at how these traditional techniques can meet modern requirements. Transport mooring arrays provide the ‘gold standard’ for... |
| Tipo: Text |
Palavras-chave: Ocean Observing; AMOC; Ocean Circulation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00595/70674/68872.pdf |
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| Ponte, Aurelien; Klein, Patrice; Capet, Xavier; Le Traon, Pierre-yves; Chapron, Bertrand; Lherminier, Pascale. |
| High-resolution numerical experiments of ocean mesoscale eddy turbulence show that the wind-driven mixed layer (ML) dynamics affects mesoscale motions in the surface layers at scales lower than O(60 km). At these scales, surface horizontal currents are still coherent to, but weaker than, those derived from sea surface height using geostrophy. Vertical motions, on the other hand, are stronger than those diagnosed using the adiabatic quasigeotrophic (QG) framework. An analytical model, based on a scaling analysis and on simple dynamical arguments, provides a physical understanding and leads to a parameterization of these features in terms of vertical mixing. These results are valid when the wind-driven velocity scale is much smaller than that associated with... |
| Tipo: Text |
Palavras-chave: Mesoscale processes; Ocean dynamics; Turbulence. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00170/28076/26291.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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| Reverdin, Gilles; Gascard, Jean-claude; Le Cann, Bernard; Prieur, Loic; Assenbaum, Michel; Lherminier, Pascale. |
| An anticyclonic mode water vortex and its environment were investigated from November 2000 to September 2001 in the northeast Atlantic (near 43.5 degrees N, 15 degrees-19 degrees W) with neutrally buoyant drifting floats, moored current meters, satellite altimetric sea surface height, and several hydrological surveys and sections. These observations reveal a coherent inner core (similar to 0 km in diameter) made of very oxygenated northeast Atlantic central waters (11 degrees-12.7 degrees C and 35.5-35.7 on the 1978 practical salinity scale) from 150 m down to about 750-m depth. The core presents high relative vorticity (up to approximately -0.5 times the Coriolis frequency f) within at least 10 km of its center, near 400-700 m. Peak velocity along the... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6357.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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| 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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| Fan, Xue; Send, Uwe; Testor, Pierre; Karstensen, Johannes; Lherminier, Pascale. |
| Mesoscale anticyclonic eddies in the Irminger Sea are observed using a mooring and a glider. Between 2002 and 2009, the mooring observed 53 anticyclones. Using a kinematic model, objective estimates of eddy length scales and velocity structure are made for 16 eddies. Anticyclones had a mean core diameter of 12 km, and their mean peak observed azimuthal speed was 0.1 m s(-1). They had core salinities and potential temperatures of 34.91-34.98 and 4.488-5.34 degrees C, respectively, making them warm and salty features. These properties represent a typical salinity anomaly of 0.03 and a temperature anomaly of 0.28 degrees C from noneddy values. All eddies had small (<< 1) Rossby numbers. In 2006, the glider observed two anticyclones having diameters of... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Eddies; Mesoscale processes. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00137/24832/22921.pdf |
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| Castrillejo, Maxi; Casacuberta, Nuria; Christl, Marcus; Vockenhuber, Christof; Synal, Hans-arno; Garcia-ibanez, Maribel; Lherminier, Pascale; Sarthou, Geraldine; Garcia-orellana, Jordi; Masque, Pere. |
| Pathways and timescales of water mass transport in the subpolar North Atlantic Ocean (SPNA) have been investigated by many studies due to their importance for the meridional overturning circulation and thus for the global ocean. In this sense, observational data on geochemical tracers provide complementary information to improve the current understanding of the circulation in the SPNA. To this end, we present the first simultaneous distribution of artificial 129I and 236U in 14 depth profiles and in surface waters along the GEOVIDE section covering a zonal transect through the SPNA in spring 2014. Our results show that the two tracers are distributed following the water mass structure and that their presence is largely influenced by the global fallout (GF)... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00457/56873/58725.pdf |
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| Desbruyeres, Damien; Mercier, Herle; Thierry, Virginie; Lherminier, Pascale; Gula, Jonathan; Cyr, F; Kieke, D; Holliday, P; Smeed, D. |
| An observational experimental setup will be proposed to investigate the dynamics and thermodynamics of the deep western boundary current in the “transition zone” of the North Atlantic, around Flemish Cap, Newfoundland. Located between the international RAPID and OSNAP mooring arrays, this region represents a unique choke point for most of the North Atlantic large-scale currents and water masses involved in the Atlantic Meridional Overturning Circulation (AMOC). Horizontal export and latitudinal coherence, water mass transformation and vertical motions, as well as shelf-slope-interior exchanges will be studied with repeat hydrography, moorings, drifting and profiling floats, and gliders. Multidisciplinary approaches are likely, including biogeochemistry and... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61502/65316.pdf |
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| Racape, Virginie; Zunino, Patricia; Mercier, Herle; Lherminier, Pascale; Bopp, Laurent; Perez, Fiz F; Gehlen, Marion. |
| The North Atlantic Ocean is a major sink region for atmospheric CO2 and contributes to the storage of anthropogenic carbon (Cant). While there is general agreement that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and storage of Cant in the North Atlantic Subpolar Ocean, processes controlling their recent variability and evolution over the 21st century remain uncertain. This study investigates the relationship between transport, air-sea flux and storage rate of Cant in the North Atlantic Subpolar Ocean over the past 53 years. Its relies on the combined analysis of a multiannual in situ data set and outputs from a global biogeochemical ocean general circulation model (NEMO-PISCES) at 1/2 degrees spatial... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00454/56587/58275.pdf |
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| Branellec, Pierre; Lherminier, Pascale. |
| Complementing the study of the variability of the North Atlantic Subpolar Gyre that is performed in the frame of the Ovide project, the East Greenland/Irminger Current (EGIC) was measured at 60°N between June 2004 to June 2006 by an array of 5 moorings, placed on a section from the shelf to the 1900m isobath. The moorings were equipped with 15 RCM currentmeters and 2 ADCPs to measure the volume transport, and also 5 micro-CTD at mooring heads (about 200m below the surface) to measure the vertical displacement of the moorings and the variability of the warm and salty water masses in the Irminger Current. The highest velocities, about 80 cm/s, are found at the top of mooring B. The core of the current is located between moorings B and C. The current... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00211/32202/30638.pdf |
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| Sarafanov, Artem; Falina, Anastasia; Lherminier, Pascale; Mercier, Herle; Sokov, Alexey; Gourcuff, Claire. |
| [1] In earlier studies, the decadal variability of the Deep Western Boundary Current (DWBC) transport in the vicinity of Cape Farewell, Greenland, has been assessed from changes in the baroclinic velocities computed from hydrographic data and referenced to 1000 m depth. The main limitation of using such an estimate as an index for the DWBC absolute transport variability comes from the unaccounted for decadal velocity changes at the reference level (1000 m). These changes may substantially contribute to the DWBC absolute transport variability by compensating for or adding to the baroclinic transport changes. To assess this contribution to variability, we quantify the decadal velocity changes which occurred at 1000 m depth southeast of Cape Farewell since... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00017/12855/9820.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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| Perez, Fiz F.; Mercier, Herle; Vazquez-rodriguez, Marcos; Lherminier, Pascale; Velo, Anton; Pardo, Paula C.; Roson, Gabriel; Rios, Aida F.. |
| Uptake of atmospheric carbon dioxide in the subpolar North Atlantic Ocean declined rapidly between 1990 and 2006. This reduction in carbon dioxide uptake was related to warming at the sea surface, which-according to model simulations-coincided with a reduction in the Atlantic meridional overturning circulation. The extent to which the slowdown of this circulation system-which transports warm surface waters to the northern high latitudes, and cool deep waters south-contributed to the reduction in carbon uptake has remained uncertain. Here, we use data on the oceanic transport of volume, heat and carbon dioxide to track carbon dioxide uptake in the subtropical and subpolar regions of the North Atlantic Ocean over the past two decades. We separate... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00135/24625/22712.pdf |
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| Daniault, Nathalie; Mercier, Herle; Lherminier, Pascale; Sarafanov, Artem; Falina, Anastasia; Zunino, Patricia; Perezf, Fiz F.; Rios, Aida F.; Ferron, Bruno; Huck, Thierry; Thierry, Virginie; Gladyshev, Sergey. |
| The decadal mean circulation in the northern North Atlantic was assessed for the early 21st century from repeated ship-based measurements along the Greenland-Portugal OVIDE line, from satellite altimetry and from earlier reported transports across 59.5°N and at the Greenland-Scotland sills. The remarkable quantitative agreement between all data sets allowed us to draw circulation pathways with a high level of confidence. The North Atlantic Current (NAC) system is composed of three main branches, referred to as the northern, central and southern branches, which were traced from the Mid-Atlantic Ridge (MAR), to the Irminger Sea, the Greenland-Scotland Ridge and the subtropical gyre. At OVIDE, the northern and central branches of the NAC fill the whole water... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00345/45569/45177.pdf |
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| Lherminier, Pascale; Mercier, Herle; Huck, Thierry; Gourcuff, Claire; Perez, Fiz F.; Morin, Pascal; Sarafanov, Artem; Falina, Anastasia. |
| The horizontal circulation of the subpolar gyre and the Meridional Overturning Circulation (MOC) are investigated here by comparing two snapshots of the North Atlantic as delivered by two hydrographic sections between Greenland and Portugal. The corresponding cruises were carried out in June–July 2002 and June–July 2004 on R/V Thalassa within the framework of the Ovide project. The absolute transports in June 2004 are described in detail, and then compared with transports in June 2002. The MOC (in density coordinates), driven by the volume balance between the northward North Atlantic Current (NAC) and the net southward export of dense water from the subpolar gyre, did not change: View the MathML source (1 Sv=106 m3 s−1). Its upper limb, above σ1=32.1, is... |
| Tipo: Text |
Palavras-chave: North Atlantic; Subpolar gyre; Meridional Overturning Circulation; OVIDE; Hydrology; ADCP. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00011/12272/9057.pdf |
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| Registros recuperados: 53 | |
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