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Registros recuperados: 12
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A Correction for the Thermal Mass-Induced Errors of CTD Tags Mounted on Marine Mammals ArchiMer
Mensah, Vigan; Roquet, Fabien; Siegelman-charbit, Lia; Picard, Baptiste; Pauthenet, Etienne; Guinet, Christophe.
The effect of thermal mass on the salinity estimate from conductivity-temperature-depth (CTD) tags sensor mounted on marine mammals is documented, and a correction scheme is proposed to mitigate its impact. The algorithm developed here allows for a direct correction of the salinity data, rather than a correction of the sample's conductivity and temperature. The amplitude of the thermal mass-induced error on salinity and its correction are evaluated via comparison between data from CTD tags and from Sea-Bird Scientific CTD used as a reference. Thermal mass error on salinity appears to be generally O(10(-2)) g kg(-1), it may reach O(10(-1)) g kg(-1), and it tends to increase together with the magnitude of the cumulated temperature gradient (T-HP) within the...
Tipo: Text Palavras-chave: Data processing; In situ oceanic observations; Instrumentation; Sensors; Profilers; Oceanic.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00585/69697/67577.pdf
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A New Platform for the Determination of Air–Sea Fluxes (OCARINA): Overview and First Results ArchiMer
Bourras, D.; Branger, H.; Reverdin, Gilles; Marie, Louis; Cambra, R.; Baggio, L.; Caudoux, C.; Caudal, G.; Morisset, S.; Geyskens, N.; Weill, Alain; Hauser, D..
The present paper describes a new type of floating platform that was specifically designed for estimating air–sea fluxes, investigating turbulence characteristics in the atmospheric surface boundary layer, and studying wind–wave interactions. With its design, it can be deployed in the open ocean or in shallow-water areas. The system is designed to be used from a research vessel. It can operate for ~10 h as a drifting wave rider and 3 h under power. Turbulence and meteorological instrument packages are placed at a low altitude (1–1.5 m). It was deployed for validation purposes during the Front de Marée, Variabilité (FROMVAR), 2011 experiment off the west coast of Brittany, France. Wind friction velocity and surface turbulent buoyancy flux were estimated...
Tipo: Text Palavras-chave: In situ atmospheric observations; Surface observations; In situ oceanic observations.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00192/30283/28759.pdf
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An Annual Cycle of Submesoscale Vertical Flow and Restratification in the Upper Ocean ArchiMer
Yu, Xiaolong; Naveira Garabato, Alberto C.; Martin, Adrian P; Buckingham, Christian; Brannigan, Liam; Su, Zhan.
Numerical simulations suggest that submesoscale turbulence may transform lateral buoyancy gradients into vertical stratification, and thus restratify the upper ocean via vertical flow. However, the observational evidence for this restratifying process has been lacking due to the difficulty in measuring such ephemeral phenomena, particularly over periods of months to years. This study presents an annual cycle of the vertical velocity and associated restratification estimated from two nested clusters of meso- and submesoscale-resolving moorings, deployed in a typical mid-ocean area of the Northeast Atlantic. Vertical velocities inferred using the non-diffusive density equation are substantially stronger at submesoscales (horizontal scales of 1-10 km) than at...
Tipo: Text Palavras-chave: Ocean; Atlantic Ocean; Ageostrophic circulations; Frontogenesis; Frontolysis; In situ oceanic observations.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00489/60076/63398.pdf
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Argos-3 Satellite Communication System: Implementation on the Arvor Oceanographic Profiling Floats ArchiMer
Andre, Xavier; Moreau, Bertrand; Le Reste, Serge.
The scientific community observes the ocean for applications in the fields of oceanography and climate research. In order to recover in situ data, more than 3,000 profiling floats are operated in the framework of the Argo Program. Each float performs cycles between the sea surface and a depth of 2,000 meters. Scientific data are gathered while the float is travelling upward from the depths of the oceans, and are then transmitted via a satellite communication system at the end of each cycle. During its time at the surface, mainly dedicated to transmissions, the float is vulnerable and subject to drift, which limits its use in many studies. Moreover, transmission times are becoming longer due to a trend towards high resolution or multi-sensor profiles....
Tipo: Text Palavras-chave: Buoy observations; In situ oceanic observations; Instrumentation; Sensors; Profilers; Oceanic.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00284/39519/38011.pdf
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Correction and Accuracy of High- and Low-Resolution CTD Data from Animal-Borne Instruments ArchiMer
Siegelman, Lia; Roquet, Fabien; Mensah, Vigan; Riviere, Pascal; Pauthenet, Etienne; Picard, Baptiste; Guinet, Christophe.
Most available CTD Satellite Relay Data Logger (CTD-SRDL) profiles are heavily compressed before satellite transmission. High-resolution profiles recorded at the sampling frequency of 0.5 Hz are, however, available upon physical retrieval of the logger. Between 2014 and 2018, several loggers deployed on elephant seals in the Southern Ocean have been set in continuous recording mode, capturing both the ascent and descent for over 60 profiles per day during several months, opening new horizons for the physical oceanography community. Taking advantage of a new dataset made of seven such loggers, a postprocessing procedure is proposed and validated to improve the quality of all CTD-SRDL data: that is, both high-resolution profiles and compressed low-resolution...
Tipo: Text Palavras-chave: Algorithms; Data processing; In situ oceanic observations.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00494/60567/64043.pdf
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Evolution of Intermediate Water Masses Based on Argo Float Displacements ArchiMer
Sevellec, Florian; Colin De Verdiere, Alain; Ollitrault, Michel.
The evolution and dispersion of intermediate water masses in the ocean interior is studied. To this purpose, an empirical statistical model of Lagrangian tracers at a constant depth level is developed. The model follows the transfer operator based on 10-day deep displacements of Argo floats at; similar to 1000m depth. An asymptotic analysis of the model shows the existence of 10 principal stationary points (the 10 locations attract asymptotically 97% of the tracers). It takes; 1000 years to reach this asymptotic regime relevant for estimating the stationary points. For Lagrangian floats, the concept of attractor needs to be generalized in a statistical sense (versus deterministic), except for a few places in the ocean. In this new framework, a tracer has a...
Tipo: Text Palavras-chave: Dynamics; Large-scale motions; In situ oceanic observations; Statistical techniques; Ocean models.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00393/50450/51180.pdf
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How deep Argo will improve the deep ocean in an ocean reanalysis ArchiMer
Gasparin, Florent; Hamon, Mathieu; Rémy, Elisabeth; Le Traon, Pierre-yves.
Global ocean sampling with autonomous floats going to 4,000 m/6,000 m, known as the deep Argo array, constitutes one of the next challenges for tracking climate change. The question here is how such global deep array will impact on ocean reanalyses. Based on the different behavior of four ocean reanalyses, we first identified that large uncertainty exist in current reanalyses in representing local heat and freshwater fluxes in the deep ocean (1 W/m2 and 10 cm/yr regionally). Additionally, temperature and salinity comparison with deep Argo observations demonstrates that reanalysis error in the deep ocean are of the same size, or even stronger, than the deep ocean signal. An experimental approach, using the 1/4◦ GLORYS2V4 system, is then presented to...
Tipo: Text Palavras-chave: Ocean; Thermocline circulation; Bottom currents; Bottom water; In situ oceanic observations; Reanalysis data; Oceanic variability.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00515/62647/67023.pdf
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Interior Water-Mass Variability in the Southern Hemisphere Oceans during the Last Decade ArchiMer
Portela, Esther; Kolodziejczyk, Nicolas; Maes, Christophe; Thierry, Virginie.
Using an Argo dataset and the ECCOv4 reanalysis, a volume budget was performed to address the main mechanisms driving the volume change of the interior water masses in the Southern Hemisphere oceans between 2006 and 2015. The subduction rates and the isopycnal and diapycnal water-mass transformation were estimated in a density-spiciness (sigma-tau) framework. Spiciness, defined as thermohaline variations along isopycnals, was added to the potential density coordinates to discriminate between water masses spreading on isopycnal layers. The main positive volume trends were found to be associated with the Subantarctic Mode Waters (SAMW) in the South Pacific and South Indian Ocean basins, revealing a lightening of the upper waters in the Southern Hemisphere....
Tipo: Text Palavras-chave: Southern Hemisphere; Water masses; Storage; Isopycnal mixing; Water budget; Balance; In situ oceanic observations; Decadal variability.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00609/72065/70771.pdf
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Measurements of Enhanced Near-Surface Turbulence Under Windrows ArchiMer
Zippel, Seth F.; Maksym, Ted; Scully, Malcolm; Sutherland, Peter; Dumont, Dany.
Observations of waves, winds, turbulence, and the geometry and circulation of windrows were made in a shallow bay in the winter of 2018 outside of Rimouski, Québec. Water velocities measured from a forward-looking pulse-coherent ADCP mounted on a small zodiac show spanwise (cross-windrow) convergence, streamwise (downwind) velocity enhancement, and downwelling in the windrows, consistent with the view that windrows are the result of counter-rotating pairs of wind-aligned vortices. The spacing of windrows, measured with acoustic backscatter and with surface imagery, was measured to be approximately twice the water depth, which suggests an aspect ratio of 1. The magnitude and vertical distribution of turbulence measured from the ADCP are consistent with a...
Tipo: Text Palavras-chave: Ocean; Atmosphere-ocean interaction; Boundary layer; Langmuir circulation; In situ oceanic observations; Surface observations.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00593/70552/68722.pdf
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Monte Carlo-Based Quantification of Uncertainties in Determining Ocean Remote Sensing Reflectance from Underwater Fixed-Depth Radiometry Measurements ArchiMer
Bialek, Agnieszka; Vellucci, Vincenzo; Gentili, Bernard; Antoine, David; Gorrono, Javier; Fox, Nigel; Underwood, Craig.
A new framework that enables evaluation of the in situ ocean color radiometry measurement uncertainty is presented. The study was conducted on the multispectral data from a permanent mooring deployed in clear open ocean water. The uncertainty is evaluated for each component of the measurement equation and data processing step that leads to deriving the remote sensing reflectance. The Monte Carlo method was selected to handle the data complexity such as correlation and nonlinearity in an efficient manner. The results are presented for a prescreened dataset that is suitable for system vicarious calibration applications. The framework provides uncertainty value per measurement taking into consideration environmental conditions present during acquisition. A...
Tipo: Text Palavras-chave: Ocean; In situ oceanic observations; Quality assurance; Control; Error analysis.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00640/75202/75334.pdf
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Observations of Layering under a Warm-Core Ring in the Gulf of Mexico ArchiMer
Meunier, Thomas; Pallas Sanz, Enric; Tenreiro, Miguel; Ochoa, Jose; Angulo, Angel Ruiz; Buckingham, Christian.
Two glider transects in the Gulf of Mexico reveal fine-vertical-scale thermohaline structures within a Loop Current eddy (LCE). Partially compensating temperature and salinity anomalies are shown to organize as thin layers below the eddy and near its edges. The anomalies have vertical scales ranging from 2 to 60 m and extend laterally over distances up to 120 km. These structures are evident in synthetic acoustic reflectivity derived from the glider data and are reminiscent of the intense layering observed in seismic imagery around meddies, Agulhas rings, and warm-core Kuroshio rings. The observed layers are aligned with the geostrophic streamfunction rather than isopycnals and develop preferentially in zones of intense vertical shear. These observations...
Tipo: Text Palavras-chave: Eddies; Mesoscale processes; Small scale processes; In situ oceanic observations; Quasigeostrophic models; Tracers.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00600/71242/69612.pdf
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Variability of the Heat and Salt Budget in the Subtropical Southeastern Pacific Mixed Layer between 2004 and 2010: Spice Injection Mechanism ArchiMer
Kolodziejczyk, Nicolas; Gaillard, Fabienne.
The mixed layer heat and salt budget in the southeastern subtropical Pacific are estimated using 7 years (2004-10) of Argo-profiling float data, surface fluxes, precipitation, surface velocity data, and wind observations and reanalysis. In this region, the mixed layer heat budget is characterized by a strong annual cycle mainly modulated by the shortwave radiation annual cycle. During the austral fall and winter, the shortwave radiation input minimum is overwhelmed by the heat loss mainly because of the latent heat flux. The mixed layer salt budget also presents a strong annual cycle with a minimum of salt content during the late austral winter. In contrast with the heat budget, the salt budget is mainly driven by the unresolved terms computed as the...
Tipo: Text Palavras-chave: Mixed layer; Heat budgets; Fluxes; Salinity; In situ oceanic observations; Interannual variability; Seasonal cycle.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00155/26587/24722.pdf
Registros recuperados: 12
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