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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... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61436/65156.pdf |
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| Lemonnier, Clarisse; Perennou, Morgan; Eveillard, Damien; Fernandez-guerra, Antonio; Leynaert, Aude; Marié, Louis; Morrison, Hilary G.; Memery, Laurent; Paillard, Christine; Maignien, Lois. |
| Ocean frontal systems are widespread hydrological features defining the transition zone between distinct water masses. They are generally of high biological importance as they are often associated with locally enhanced primary production by phytoplankton. However, the composition of bacterial communities in the frontal zone remains poorly understood. In this study, we investigate how a coastal tidal front in Brittany (France) structures the free-living bacterioplankton communities in a spatio-temporal survey across four cruises, five stations and three depths. We used 16S rRNA gene surveys to compare bacterial community structures across 134 seawater samples and defined groups of co-varying taxa (modules) exhibiting coherent ecological patterns across... |
| Tipo: Text |
Palavras-chave: Marine front; Bacterial communities; Dynamic; Network; Ecological strategies. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74657/74557.pdf |
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| Marié, Louis; Collard, Fabrice; Nouguier, Frederic; Pineau-guillou, Lucia; Hauser, Danièle; Boy, François; Méric, Stéphane; Sutherland, Peter; Peureux, Charles; Monnier, Goulven; Chapron, Bertrand; Martin, Adrien; Dubois, Pierre; Donlon, Craig; Casal, Tania; Ardhuin, Fabrice. |
| Surface currents are poorly known over most of the world's oceans. Satellite-borne Doppler wave and current scatterometers (DWaCSs) are among the proposed techniques to fill this observation gap. The Sea surface KInematics Multiscale (SKIM) proposal is the first satellite concept built on a DWaCS design at near-nadir angles and was demonstrated to be technically feasible as part of the European Space Agency Earth Explorer program. This article describes preliminary results from a field experiment performed in November 2018 off the French Atlantic coast, with sea states representative of the open ocean and a well-known tide-dominated current regime, as part of the detailed design and feasibility studies for SKIM. This experiment comprised airborne... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00658/77056/78354.pdf |
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| Rascle, Nicolas; Chapron, Bertrand; Molemaker, Jeroen; Nouguier, Frederic; Ocampo‐torres, Francisco J.; Osuna Cañedo, J. Pedro; Marié, Louis; Lund, Björn; Horstmann, Jochen. |
| Sea surface roughness is affected by surface current gradients, which provides a means of monitoring from satellite sharp oceanic fronts. This paper is the second report of an experiment designed to compare observations of sea surface roughness and surface currents at an unprecedented accuracy, owing to the conjunction of numerous deployed drifters and roughness instruments. About 200 drifters sampled a thin 10~km elongated submesoscale front, also monitored by a high density of roughness instruments: satellite Synthetic Aperture Radar, satellite and airborne multi‐angle sunglint radiometers. The first paper focused on the retrieval of the current gradient direction (convergence and cyclonic vorticity) at the front, using roughness observations at multiple... |
| Tipo: Text |
Palavras-chave: Sea surface roughness; Submesoscale current; Fine-scale current; Synthetic aperture radar (SAR); Sunglint Sun glitter; Ocean front. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00636/74788/75035.pdf |
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| Ramond, Pierre; Siano, Raffaele; Schmitt, Sophie; De Vargas, Colomban; Marié, Louis; Memery, Laurent; Sourisseau, Marc. |
| Oceanic physics at fine scale; e.g. eddies, fronts, filaments; are notoriously difficult to sample. However, an increasing number of theoretical approaches hypothesize that these processes affect phytoplankton diversity which have cascading effects on regional ecosystems. In 2015, we targeted the Iroise Sea (France) and evidenced the setting up of the Ushant tidal front from the beginning of spring to late summer. Seawater samples were taken during three sampling cruises and DNA-barcoding allowed us to investigate patterns of eukaryotic phytoplankton diversity across this front. First focusing on patterns of taxonomic richness, we evidenced that the front harbored a hotspot of eukaryotic phytoplankton diversity sustained throughout summer. We then detail... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78933/81307.pdf |
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| Ardhuin, Fabrice; Brandt, Peter; Gaultier, Lucile; Donlon, Craig; Battaglia, Alessandro; Boy, François; Casal, Tania; Chapron, Bertrand; Collard, Fabrice; Cravatte, Sophie; Delouis, Jean Marc; De Witte, Erik; Dibarboure, Gerald; Engen, Geir; Johnsen, Harald; Lique, Camille; Lopez-dekker, Paco; Maes, Christophe; Martin, Adrien; Marié, Louis; Menemenlis, Dimitris; Nouguier, Frederic; Peureux, Charles; Rampal, Pierre; Ressler, Gerhard; Rio, Marie-helene; Rommen, Bjorn; Shutler, Jamie D.; Suess, Martin; Tsamados, Michel; Ubelmann, Clement; Van Sebille, Erik; Van Den Oever, Martin; Stammer, Detlef. |
| The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented direct measurements of strong currents, from boundary currents to the Antarctic circumpolar current, and their interaction with ocean waves with expected impacts on air-sea fluxes and extreme waves. For the first time, SKIM will directly measure the ocean surface current vector from space. The main instrument on SKIM is a Ka-band conically scanning, multi-beam Doppler radar altimeter/wave scatterometer that includes a... |
| Tipo: Text |
Palavras-chave: Ocean current; Tropics; Arctic; Doppler; Altimetry; Sea state; Remote sensing; Ocean waves. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60964/64372.pdf |
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| Lopez, G.; Bennis, Anne-claire; Barbin, Y.; Sentchev, A.; Benoit, L.; Marié, Louis. |
| Two weeks of high-frequency radar measurements collected at the Alderney Race are compared with the results of a three-dimensional fully coupled wave–current model. Spatial current measurements are rare in this site, otherwise well investigated through modelling. Thus, the radar measurements offer a unique opportunity to examine the spatial reliability of numerical results, and can help to improve our understanding of the complex currents in the area. Comparison of observed and modelled surface current velocities showed a good agreement between the methods, represented by root mean squared errors ranging from 14 to 40 cm s−1 and from 18 to 60 cm s−1 during neap and spring tides, respectively. Maximum errors were found in shallow regions with consistently... |
| Tipo: Text |
Palavras-chave: HF radar; Surface current; Alderney Race; MARS 3D; WW3; High-frequency radar. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75516/78391.pdf |
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