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| Registros recuperados: 36 | |
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| Viatte, Camille; Clerbaux, Cathy; Maes, Christophe; Daniel, Pierre; Garello, René; Safieddine, Sarah; Ardhuin, Fabrice. |
| Air pollution and sea pollution are both impacting human health and all the natural environments on Earth. These complex interactions in the biosphere are becoming better known and understood. Major progress has been made in recent past years for understanding their societal and environmental impacts, thanks to remote sensors placed aboard satellites. This paper describes the state of the art of what is known about air pollution and focuses on specific aspects of marine pollution, which all benefit from the improved knowledge of the small-scale eddy field in the oceans. Examples of recent findings are shown, based on the global observing system (both remote and in situ) with standardized protocols for monitoring emerging environmental threats at the global... |
| Tipo: Text |
Palavras-chave: Pollution; Atmosphere; Ocean; Space-borne instrument. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74687/74596.pdf |
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| Bourras, Denis; Cambra, Remi; Marié, Louis; Bouin, Marie-noëlle; Baggio, Lucio; Branger, Hubert; Beghoura, Houda; Reverdin, Gilles; Dewitte, Boris; Paulmier, Aurélien; Maes, Christophe; Ardhuin, Fabrice; Pairaud, Ivane; Fraunié, Philippe; Luneau, Christopher; Hauser, Danièle. |
| Turbulent fluxes at the air‐sea interface are estimated with data collected in 2011 to 2017 with a low‐profile platform during six experiments in four regions. The observations were carried out with moderate winds (2‐10 m s‐1) and averaged wave heights of 1.5 m. Most of the time, there was a swell, with an averaged wave age (the ratio between wave phase speed and wind speed) being equal to 2.8±1.6. Three flux calculation methods are used, namely the eddy‐covariance (EC), the inertial‐dissipation (ID), and the bulk methods. For the EC method, a spectral technique is proposed to correct wind data from platform motion. A mean bias affecting the friction velocity (u*) is then evaluated. The comparison between EC u* and ID u* estimates suggests that a constant... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61436/65156.pdf |
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| Maes, Christophe; Sudre, Loupe Joeel; Garcon, Veronique. |
| The analysis of satellite-based ocean color data shows that low concentrations of surface chlorophyll-a (chl-a) found in the equatorial region of the Pacific Ocean varies in phase with the eastern edge of the warm pool. As is true for high sea surface temperatures, the existence and maintenance of these low concentrations are linked to the upper ocean stratification due to salinity. The present study also establishes the quasi permanence of a frontal zone in chlorophyll-a separating the regimes of the western region and the eastern-central cold tongue and, through the identification of this front in satellite-based ocean color data, it provides, for the first time, a reliable method for locating the eastern edge of the warm pool from surface observations... |
| Tipo: Text |
Palavras-chave: El nino; Enso. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00208/31884/30309.pdf |
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| Hernandez-ayon, Jose M.; Paulmier, Aurélien; Garcon, Veronique; Sudre, Joel; Montes, Ivonne; Chapa-balcorta, Cecilia; Durante, Giovanni; Dewitte, Boris; Maes, Christophe; Bretagnon, Marine. |
| The oxygen minimum zone (OMZ) of Peru is recognized as a source of CO2 to the atmosphere due to upwelling that brings water with high concentrations of dissolved inorganic carbon (DIC) to the surface. However, the influence of OMZ dynamics on the carbonate system remains poorly understood given a lack of direct observations. This study examines the influence of a coastal Eastern South Pacific OMZ on carbonate system dynamics based on a multidisciplinary cruise that took place in 2014. During the cruise, onboard DIC and pH measurements were used to estimate pCO2 and to calculate the calcium carbonate saturation state (Ω aragonite and calcite). South of Chimbote (9°S), water stratification decreased and both the oxycline and carbocline moved from 150 m depth... |
| Tipo: Text |
Palavras-chave: OMZ; DIC; PH; Omega aragonite; Upwelling Peruvian system. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70004/67919.pdf |
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| Sauzède, Raphaëlle; Martinez, Elodie; Maes, Christophe; De Fommervault, Orens Pasqueron; Poteau, Antoine; Mignot, Alexandre; Claustre, Hervé; Uitz, Julia; Oziel, Laurent; Maamaatuaiahutapu, Keitapu; Rodier, Martine; Schmechtig, Catherine; Laurent, Victoire. |
| The South Pacific Subtropical Gyre (SPSG) is a vast and remote oceanic system where the variability in phytoplankton biomass and production is still largely uncertain due to the lack of in situ biogeochemical observations. The SPSG is an oligotrophic environment where the ecosystem is controlled predominantly by nutrient depletion in surface waters. However, this dynamic is altered in the vicinity of islands where increased biological activity occurs (i.e. the island mass effect, IME). This study mainly focuses on in situ observations which show evidence of an IME leeward of Tahiti (17.7°S - 149.5°W), French Polynesia. Physical and biogeochemical observations collected with two Biogeochemical-Argo profiling floats are used to investigate the dynamics of... |
| Tipo: Text |
Palavras-chave: Phytoplankton biomass; Biogeochemical-Argo floats; Island mass effect; South Pacific Subtropical Gyre. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71130/69445.pdf |
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| Fumenia, Alain; Moutin, Thierry; Bonnet, Sophie; Benavides, Mar; Petrenko, Anne; Helias Nunige, Sandra; Maes, Christophe. |
| As part of the Oligotrophy to UlTra-oligotrophy PACific Experiment cruise, which took place in the Western Tropical South Pacific during the austral summer (March–April 2015), we present data on nitrate, phosphate and on particulate and dissolved organic matter. The stoichiometric nitrogen-to-phosphorus ratios of the inorganic and organic material and the tracer N* are described. N* allows to trace changes in the proportion of fixed nitrogen due to diazotrophy and/or denitrification. Our results showed that the Melanesian archipelago waters between 160° E and 170° W are characterized by a deficit of nitrate and phosphate in the productive layer, significant dinitrogen fixation rates and an excess of particulate organic nitrogen compared to the canonical... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00422/53383/54232.pdf |
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| Martinez, Elodie; Raapoto, Hirohiti; Maes, Christophe; Maamaatuaihutapu, Keitapu. |
| The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the... |
| Tipo: Text |
Palavras-chave: Tropical instability waves; La Nina; Chlorophyll-a concentration variability; Ocean colour; Island mass effect; Marquesas islands; Oceanography; Satellite observations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54858/56346.pdf |
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| Barbot, Simon; Petrenko, Anne; Maes, Christophe. |
| Thanks to the autonomous Argo floats of the OUTPACE cruise (Oligotrophy to UlTra-oligotrophy PACific Experiment) and of the THOT (TaHitian Ocean Time series) project, some features of intermediate-flow dynamics, at around 1000 m depth, within the central and western South Pacific Ocean (around 19° S, 156° E–150° W) are described. In the Coral Sea, we highlight minima in dissolved oxygen of 140 µmol kg−1 that are associated with the signature of a southward transport of waters between two zonal jets: from the North Vanuatu Jet to the North Caledonia Jet. This transport takes place in the core of a cyclonic eddy or via the path between a cyclonic eddy and an anticyclonic one, highlighting the importance of mesoscale dynamics in upper thermocline and surface... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/56005/57512.pdf |
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| Guieu, Cecile; Bonnet, Sophie; Petrenko, Anne; Menkes, Christophe; Chavagnac, Valerie; Desboeufs, Karine; Maes, Christophe; Moutin, Thierry. |
| In the Western Tropical South Pacific, patches of high chlorophyll concentrations linked to the occurrence of N2-fixing organisms are found in the vicinity of volcanic islands. The survival of these organisms relies on a high bioavailable iron supply whose origin and fluxes remain unknown. Here, we measured high dissolved iron (DFe) concentrations (up to 66 nM) in the euphotic layer, extending zonally over 10 degrees longitude (174 E−175 W) at ∼20°S latitude. DFe atmospheric fluxes were at the lower end of reported values of the remote ocean and could not explain the high DFe concentrations measured in the water column in the vicinity of Tonga. We argue that the high DFe concentrations may be sustained by a submarine source, also characterized by... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00444/55564/57174.pdf |
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| Dobler, Delphine; Huck, Thierry; Maes, Christophe; Grima, Nicolas; Blanke, Bruno; Martinez, Elodie; Ardhuin, Fabrice. |
| In the open ocean, floating surface debris such as plastics concentrate in five main accumulation zones centered around 30° latitude, far from highly turbulent areas. Using Lagrangian advection of numerical particles by surface currents from ocean model reanalysis, previous studies have shown long-distance connection from the accumulation zones of the South Indian to the South Pacific oceans. An important physical process affecting surface particles but missing in such analyses is wave-induced Stokes drift. Taking into account surface Stokes drift from a wave model reanalysis radically changes the fate of South Indian particles. The convergence region moves from the east to the west of the basin, so particles leak to the South Atlantic rather than the... |
| Tipo: Text |
Palavras-chave: Marine debris; Microplastics; Stokes drift; Indian Ocean; Lagrangian analysis; Ocean surface pathways. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62320/69273.pdf |
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| Rousselet, Louise; De Verneil, Alain; Doglioli, Andrea M.; Petrenko, Anne A.; Duhamel, Solange; Maes, Christophe; Blanke, Bruno. |
| The patterns of the large-scale, meso- and submesoscale surface circulation on biogeochemical and biological distributions are examined in the Western Tropical South Pacific (WTSP) in the context of the OUTPACE cruise (Feb–April 2015). Multi-disciplinary original in situ observations were achieved along a zonal transect through the WTSP and their analysis was coupled with satellite data. The use of Lagrangian diagnostics allows for the identification of water mass pathways, mesoscale structures, and submesoscale features such as fronts. In particular, we confirmed the existence of a global wind-driven southward circulation of surface waters in the entire WTSP, using a new high-resolution altimetry-derived product, validated by in situ drifters, that... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00420/53119/54071.pdf |
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| Bretagnon, Marine; Paulmier, Aurelien; Garcon, Veronique; Dewitte, Boris; Illig, Serena; Leblond, Nathalie; Coppola, Laurent; Campos, Fernando; Velazco, Federico; Panagiotopoulos, Christos; Oschlies, Andreas; Martin Hernandez-ayon, J.; Maske, Helmut; Vergara, Oscar; Montes, Ivonne; Martinez, Philippe; Carrasco, Edgardo; Grelet, Jacques; Desprez-de-gesincourt, Olivier; Maes, Christophe; Scouarnec, Lionel. |
| The fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O-2 conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. Data provided high-temporal-resolution O-2 series characterising two seasonal steady states at the... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00486/59764/62889.pdf |
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| Cassianides, Angelina; Martinez, Elodie; Maes, Christophe; Carton, Xavier; Gorgues, Thomas. |
| The Marquesas islands are a place of strong phytoplanktonic enhancement, whose original mechanisms have not been explained yet. Several mechanisms such as current−bathymetry interactions or island run-off can fertilize waters in the immediate vicinity or downstream of the islands, allowing phytoplankton enhancement. Here, we took the opportunity of an oceanographic cruise carried out at the end of 2018, to combine in situ and satellite observations to investigate two phytoplanktonic blooms occurring north and south of the archipelago. First, Lagrangian diagnostics show that both chlorophyll-a concentrations (Chl) plumes are advected from the islands. Second, the use of Finite-size Lyaponov Exponent and frontogenesis diagnostics reveal how the Chl plumes... |
| Tipo: Text |
Palavras-chave: Mesoscale dynamics; Chlorophyll-a concentration variability; Coastal fertilization; Horizontal advection; Marquesas islands. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00649/76115/77077.pdf |
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| Gasparin, Florent; Ganachaud, Alexandre; Maes, Christophe; Marin, Frederic; Eldin, Gerard. |
| Thermocline waters of the tropical southwest Pacific can be traced back to the center of the South Pacific basin and have a potential influence on equatorial surface conditions and on the characteristics of the El Nino Southern Oscillation on decadal timescales. The Solomon Sea is traversed by this influential flow, and therefore is an optimal place for exploring this oceanic connection to the equator. From a high-resolution hydrographic survey at which we applied an inverse box model, we describe the main pathways at the entrance of the Solomon Sea, and more particularly the extremely sharp bend of the western boundary current around the south-east tip of Papua New Guinea. Of the 30 Sv subtropical waters transported into the Coral Sea from the east, above... |
| Tipo: Text |
Palavras-chave: Coral Sea; Solomon Sea; Oceanic transport. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00214/32501/30985.pdf |
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| O'Kane, Terence J.; Monselesan, Didier P.; Maes, Christophe. |
| Despite recent advances in ocean observing arrays and satellite sensors, there remains great uncertainty in the large-scale spatial variations of upper ocean salinity on the interannual to decadal timescales. Consonant with both broad-scale surface warming and the amplification of the global hydrological cycle, observed global multidecadal salinity changes typically have focussed on the linear response to anthropogenic forcing but not on salinity variations due to changes in the static stability and or variability due to the intrinsic ocean or internal climate processes. Here, we examine the static stability and spatiotemporal variability of upper ocean salinity across a hierarchy of models and reanalyses. In particular, we partition the variance into time... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00342/45321/44780.pdf |
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| Registros recuperados: 36 | |
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