Consulta: subjectFacets:"Global ocean"
Registros recuperados: 12
Data/hora: 11/06/2024 10:15:24

Improved description of the ocean mesoscale variability by combining four satellite altimeters - art. no. L02611
Provedor de dados: 5
Autores: Pascual, Ananda; Faugere, Yannice; Larnicol, Gilles; Le Traon, Pierre-yves.
Data from four satellite altimeters are combined with the aim of improving the representation of the mesoscale variability in the Global Ocean. All missions [Jason-1, ERS-2/ENVISAT, Topex/Poseidon interleaved with Jason-1 and Geosat Follow-On] are cross-calibrated previously to produce weekly gridded maps. In areas of intense variability, the rms differences between a classical configuration of two altimeters and the scenario merging four missions can reach 10 cm and 400 cm(2)/s(2) in SLA and EKE, respectively, which represents an important percentage of the signal variance. A comparison with surface drifters shows that the four altimeter scenario improves the recovery of mesoscale structures that were not properly sampled with Jason(-1) + ERS-2/ENVISAT....
Tipo: Text
Palavras-chave: Satellite altimeters; Mesoscale variability; Global ocean.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1038.pdf

Processes Driving Global Interior Ocean pH Distribution
Provedor de dados: 5
Autores: Lauvset, S. K.; Carter, B. R.; Perez, Ff; Jiang, L-q; Feely, R. A.; Velo, A.; Olsen, A.
Ocean acidification evolves on the background of a natural ocean pH gradient that is the result of the interplay between ocean mixing, biological production and remineralization, calcium carbonate cycling, and temperature and pressure changes across the water column. While previous studies have analyzed these processes and their impacts on ocean carbonate chemistry, none have attempted to quantify their impacts on interior ocean pH globally. Here we evaluate how anthropogenic changes and natural processes collectively act on ocean pH, and how these processes set the vulnerability of regions to future changes in ocean acidification. We use the mapped data product from the Global Ocean Data Analysis Project version 2, a novel method to estimate preformed...
Tipo: Text
Palavras-chave: PH; Remineralization; CaCO3; Anthropogenic; Global ocean.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00676/78793/81066.pdf

Biogeography of tuna and billfish communities
Provedor de dados: 5
Autores: Reygondeau, Gabriel; Maury, Olivier; Beaugrand, Gregory; Fromentin, Jean-marc; Fonteneau, Alain; Cury, Philippe.
Aim The aims of this study were: (1) to identify global communities of tuna and billfish species through quantitative statistical analyses of global fisheries data; (2) to describe the spatial distribution, main environmental drivers and species composition of each community detected; and (3) to determine whether the spatial distribution of each community could be linked to the environmental conditions that affect lower trophic levels by comparing the partitions identified in this study with Longhursts biogeochemical provinces. Location The global ocean from 60 degrees S to 65 degrees N. Methods We implemented a new numerical procedure based on a hierarchical clustering method and a nonparametric probabilistic test to divide the oceanic biosphere into...
Tipo: Text
Palavras-chave: Biogeochemical provinces; Global ocean; Istiophorus; Katsuwonus; Macroecology; Makaira; Marine biogeography; Tetrapturus; Thunnus; Xiphias.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00060/17141/14716.pdf

Global patterns and inferences of tuna movements and trophodynamics
Provedor de dados: 5
Autores: Logan, J.m.; Pethybridge, Heidi; Lorrain, Anne; Somes, C.; Allain, Valerie; Bodin, Nathalie; Choy, C.a.; Duffy, L.; Goñi, N.; Graham, B.; Langlais, C.; Ménard, F.; Olson, R.; Young, J.
A global dataset of carbon stable isotope (δ13C) values from yellowfin, bigeye, and albacore tuna muscle tissue (n = 4275) was used to develop a novel tool to infer broad-scale movement and residency patterns of these highly mobile marine predators. This tool was coupled with environmental models and lipid content (C:N ratio) of tuna muscle tissues to examine ocean warming impacts on tuna ecology and bioenergetic condition across Longhurst provinces. Over a 16-year study period (2000–2015), latitudinal gradients in tuna δ13C values were consistent, with values decreasing with increasing latitude. Tuna δ13C values, reflecting modelled global phytoplankton δ13C landscapes (“isoscapes”), were largely related to spatial changes in oxygen concentrations at...
Tipo: Text
Palavras-chave: Albacore tuna; Bigeye tuna; Yellowfin tuna; Carbon isotope analysis; Movement indicators; Global ocean; Fisheries management.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00617/72943/71964.pdf

Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution
Provedor de dados: 5
Autores: Barnier, B; Madec, G; Penduff, T; Molines, J; Treguier, Anne-marie; Le Sommer, J; Beckmann, A; Biastoch, A; Boning, C; Dengg, J; Derval, C; Durand, E; Gulev, S; Remy, E; Talandier, Claude; Theetten, Sebastien; Maltrud, M; Mcclean, J; De Cuevas, B.
Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4 degrees) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy-enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are...
Tipo: Text
Palavras-chave: Eddy/topography interactions; Partial step topography; Momentum advection scheme; Eddy permitting ocean model; Global ocean.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3514.pdf

Subtropical Mode Waters and Permanent Pycnocline properties in the World Ocean
Provedor de dados: 5
Autores: Feucher, Charlene; Maze, Guillaume; Mercier, Herle.
A global reference state of the subtropical mode waters and permanent pycnoclines properties for the 2000‐2015 period is presented. The climatology is obtained from a pattern recognition algorithm applied to stratification profiles from the Argo global array. The stratification features are identified as permanent upper ocean pycnostad and pycnocline even when the seasonal pycnocline is developed. The climatology shows that both Northern Hemisphere subtropical gyres have a qualitatively very similar stratification structure. The permanent pycnocline in the North Atlantic and North Pacific show two deep centers colocated with thick subtropical and subpolar mode waters. These centers coincide with modes in the density and stratification space. These deep...
Tipo: Text
Palavras-chave: Subtropical gyre; Pycnocline; Argo; Global ocean; Stratification.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59176/61817.pdf

Climatological distributions of pH, pCO(2), total CO2, alkalinity, and CaCO3 saturation in the global surface ocean, and temporal changes at selected locations
Provedor de dados: 5
Autores: Takahashi, Taro; Sutherland, S. C.; Chipman, D. W.; Goddard, J. G.; Ho, Cheng; Newberger, Timothy; Sweeney, Colm; Munro, D. R.
Climatological mean monthly distributions of pH in the total H+ scale, total CO2 concentration (TCO2), and the degree of CaCO3 saturation for the global surface ocean waters (excluding coastal areas) are calculated using a data set for pCO(2), alkalinity and nutrient concentrations in surface waters (depths &lt;50 m), which is built upon the GLODAP, CARINA and LDEO databases. The mutual consistency among these measured parameters is demonstrated using the inorganic carbon chemistry model with the dissociation constants for carbonic acid by Lueker et al. (2000) and for boric acid by Dickson (1990). Linear potential alkalinity-salinity relationships are established for 24 regions of the global ocean. The mean monthly distributions of pH and carbon chemistry...
Tipo: Text
Palavras-chave: Global ocean; Surface water; PH; Carbonate chemistry; Climatology; Seasonal and decadal change.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40098/38796.pdf

Genomic ecology of Marine Group II, the most common marine planktonic Archaea across the surface ocean
Provedor de dados: 5
Autores: Pereira, Olivier; Hochart, Corentin; Auguet, Jean-christophe; Debroas, Didier; Galand, Pierre E.
Planktonic Archaea have been detected in all the world's oceans and are found from surface waters to the deep sea. The two most common Archaea phyla are Thaumarchaeota and Euryarchaeota. Euryarchaeota are generally more common in surface waters, but very little is known about their ecology and their potential metabolisms. In this study, we explore the genomic ecology of the Marine Group II (MGII), the main marine planktonic Euryarchaeota, and test if it is composed of different ecologically relevant units. We re‐analyzed Tara Oceans metagenomes from the photic layer and the deep ocean by annotating sequences against a custom MGII database and by mapping gene co‐occurrences. Our data provide a global view of the distribution of Euryarchaeota, and more...
Tipo: Text
Palavras-chave: 16S rRNA; Euryarchaeota; Global ocean; Metagenomics; Poseidoniales; Proteorhodopsin.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00505/61676/65607.pdf

Linking ocean biogeochemical cycles and ecosystem structure and function: results of the complex SWAMCO-4 model
Provedor de dados: 5
Autores: Pasquer, B; Laruelle, G; Becquevort, S; Schoemann, V; Goosse, H; Lancelot, C.
We present results obtained with SWAMCO-4, a complex model of the marine planktonic system calculating C, N, P, Si, Fe cycling within the upper ocean, the export production and the exchange of CO2 between the ocean and atmosphere. The model, constrained by physical, chemical and biological (grazing, lysis) controls, explicitly details the dynamics of four relevant phytoplankton functional groups with respect to C, N, P, Si, Fe cycling and climate change. Those are diatoms, pico/nano phytoplankton, coccolithophorids, and Phaeocystis spp. whose growth regulation by light, temperature and nutrients has been obtained based on a comprehensive analysis of literature reviews on these taxonomic groups. The performance of SWAMCO-4 is first evaluated in a 1D...
Tipo: Text
Palavras-chave: Ecological modelling; Diatoms; Pico/nanophytoplankton; Coccolithophorids; Phaeocystis spp.; Iron; Air-sea CO2 fluxes; Global ocean; Antarctic ocean; North Atlantic.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00232/34302/32677.pdf

Detection of Coccolithophore Blooms With BioGeoChemical‐Argo Floats
Provedor de dados: 5
Autores: Terrats, L.; Claustre, H.; Cornec, M.; Mangin, A.; Neukermans, G.
Coccolithophores (calcifying phytoplankton) form extensive blooms in temperate and subpolar oceans as evidenced from ocean‐color satellites. This study examines the potential to detect coccolithophore blooms with BioGeoChemical‐Argo (BGC‐Argo) floats, autonomous ocean profilers equipped with bio‐optical and physicochemical sensors. We first matched float data to ocean‐color satellite data of calcite concentration to select floats that sampled coccolithophore blooms. We identified two floats in the Southern Ocean, which measured the particulate beam attenuation coefficient (cp) in addition to two core BGC‐Argo variables, Chlorophyll‐a concentration ([Chl‐a]) and the particle backscattering coefficient (bbp). We show that coccolithophore blooms can be...
Tipo: Text
Palavras-chave: Coccolithophores; Emiliania huxleyi; Bloom detection; BGC‐Argo floats; Bio‐optics; Global ocean.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00660/77209/78652.pdf

Estimates of Water-Column Nutrient Concentrations and Carbonate System Parameters in the Global Ocean: A Novel Approach Based on Neural Networks
Provedor de dados: 5
Autores: Sauzede, Raphaelle; Claustre, Hervé; Bittig, Henry; Pasqueron De Fommervault, Orens; Gattuso, Jean-pierre; Legendre, Louis; Johnson, Kenneth S.
A neural network-based method (CANYON: CArbonate system and Nutrients concentration from hYdrological properties and Oxygen using a Neural-network) was developed to estimate water-column biogeochemically relevant variables in the Global Ocean. These are the concentrations of 3 nutrients [nitrate (NO3−), phosphate (PO43−) and silicate (Si(OH)4)] and 4 carbonate system parameters [total alkalinity (AT), dissolved inorganic carbon (CT), pH (pHT) and partial pressure of CO2 (pCO2)], which are estimated from concurrent in situ measurements of temperature, salinity, hydrostatic pressure and oxygen (O2) together with sampling latitude, longitude and date. Seven neural-networks were developed using the GLODAPv2 database, which is largely representative of the...
Tipo: Text
Palavras-chave: Neural network; Nutrients; Carbonate system; Global ocean; GLODAPv2 database; Profiling floats.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00383/49467/49952.pdf

Bio-optical anomalies in the world's oceans: An investigation on the diffuse attenuation coefficients for downward irradiance derived from biogeochemical Argo float measurements
Provedor de dados: 5
Autores: Organelli, Emanuele; Claustre, Herve; Bricaud, Annick; Barbieux, Marie; Uitz, Julia; D'Ortenzio, Fabrizio; Dall'Olmo, Giorgio.
Identification of oceanic regions characterized by particular optical properties is extremely important for ocean color applications. The departure from globally established bio-optical models introduces uncertainties in the retrieval of biogeochemical quantities from satellite observations. Thanks to an array of 105 Biogeochemical Argo floats acquiring almost daily downward irradiance measurements at selected wavelengths in the UV and blue region of the spectrum, we re-examined the natural variability of the spectral diffuse attenuation coefficients, Kd(λ), among the world's oceans and compared them to previously established bio-optical models. The analysis of 2847 measurements of Kd(λ) at 380 and 490 nm, within the first optical depth, provided a...
Tipo: Text
Palavras-chave: Bio-optical anomalies; Light attenuation; Biogeochemical Argo floats; Global ocean; Colored dissolved organic matter.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00383/49463/49948.pdf