Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: 

RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 7
Primeira ... 1 ... Última
Imagem não selecionada

Imprime registro no formato completo
High‐frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean ArchiMer
Su, Zhan; Torres, Hector; Klein, Patrice; Thompson, Andrew F; Siegelman, Lia; Wang, Jinbo; Menemenlis, Dimitris; Hill, Christopher.
he rate of ocean heat uptake depends on the mechanisms that transport heat between the surface and the ocean interior. A recent study found that the vertical heat transport driven by motions with scales smaller than 50 km (submesoscales) and frequencies smaller than one day‐1 is upward. This transport competes with the other major components of the global heat transport, namely the downward heat transport explained by the large‐scale wind‐driven vertical circulation and vertical diffusion at small scales, and the upward heat transport associated with mesoscale eddies (50‐300 km size). The contribution from motions with small spatial scales (< 50 km) and frequencies larger than one day‐1, including internal gravity waves, has never been explicitly...
Tipo: Text Palavras-chave: Ocean heat transport<; /AUTHOR_KEYWORD>; High frequency<; /AUTHOR_KEYWORD>; Ocean front<; /AUTHOR_KEYWORD>; Eddies<; /AUTHOR_KEYWORD>; Eddy transport<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00643/75508/76354.pdf
Imagem não selecionada

Imprime registro no formato completo
Enhanced vertical mixing in coastal upwelling systems driven by diurnal-inertial resonance: numerical experiments ArchiMer
Fearon, Giles; Herbette, Steven; Veitch, Jennifer; Cambon, Gildas; Lucas, Andrew J.; Lemarié, Florian; Vichi, Marcello.
The land‐sea breeze is resonant with the inertial response of the ocean at the critical latitude of 30°N/S. 1D‐vertical numerical experiments were undertaken to study the key drivers of enhanced diapycnal mixing in coastal upwelling systems driven by diurnal‐inertial resonance near the critical latitude. The effect of the land boundary was implicitly included in the model through the `Craig approximation' for first order cross‐shore surface elevation gradient response. The model indicates that for shallow water depths (<~100~m), bottom shear stresses must be accounted for in the formulation of the ‘Craig approximation’, as they serve to enhance the cross‐shore surface elevation gradient response, while reducing shear and mixing at the thermocline. The...
Tipo: Text Palavras-chave: Inertial oscillations<; /AUTHOR_KEYWORD>; Land-sea breeze<; /AUTHOR_KEYWORD>; Diurnal-inertial resonance<; /AUTHOR_KEYWORD>; Coastal upwelling<; /AUTHOR_KEYWORD>; Diapycnal mixing<; /AUTHOR_KEYWORD>; Phytoplankton blooms<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00643/75507/76384.pdf
Imagem não selecionada

Imprime registro no formato completo
Scalewise Return‐to‐Isotropy in Stratified Boundary Layer Flows ArchiMer
Ayet, Alex; Katul, G. G.; Bragg, A. D.; Redelsperger, Jean-luc.
Anisotropic turbulence is ubiquitous in atmospheric and oceanic boundary layers due to differences in energy injection mechanisms. Unlike mechanical production that injects energy in the streamwise velocity component, buoyancy affects only the vertical velocity component. This anisotropy in energy sources, quantified by the flux Richardson number Ri f , is compensated by a `return to isotropy' (RTI) tendency of turbulent flows. Describing RTI in Reynolds‐averaged models and across scales continues to be a challenge in stratified turbulent flows. Using phenomenological models for spectral energy transfers, the necessary conditions for which the widely used Rotta model captures RTI across various Ri f and eddy sizes is discussed for the first time. This work...
Tipo: Text Palavras-chave: Boundary layer turbulence<; /AUTHOR_KEYWORD>; Rotta model<; /AUTHOR_KEYWORD>; Turbulence closure models<; /AUTHOR_KEYWORD>; Stratified turbulence<; /AUTHOR_KEYWORD>; Return to isotropy<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00641/75294/75753.pdf
Imagem não selecionada

Imprime registro no formato completo
Climate‐driven weathering shifts between highlands and floodplains ArchiMer
Yu, Zhaojie; Colin, Christophe; Bassinot, Franck; Wan, Shiming; Bayon, Germain.
Chemical weathering of silicate rocks on continents is thought to have played an important role in the evolution of past atmospheric carbon dioxide over geologic timescales. However, the detailed links between continental weathering and climate change over shorter timescales, and their potential impact on sediment records deposited in the ocean, remain poorly understood. Here, we present clay mineralogy and strontium‐neodymium isotopic data for marine sediment records from the Northern Indian Ocean, with the aim of investigating the weathering response of large Himalayan river basins to orbital and millennial climate forcing. We show that past glaciated episodes of the late Quaternary corresponded to periods of increased physical erosion, associated with...
Tipo: Text Palavras-chave: Climate change<; /AUTHOR_KEYWORD>; Continental weathering<; /AUTHOR_KEYWORD>; Highlands and floodplains<; /AUTHOR_KEYWORD>; Carbon cycle<; /AUTHOR_KEYWORD>; Himalaya<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00632/74434/74154.pdf
Imagem não selecionada

Imprime registro no formato completo
Ice Breakup Controls Dissipation of Wind Waves Across Southern Ocean Sea Ice ArchiMer
Ardhuin, Fabrice; Otero, Mark; Merrifield, Sophia; Grouazel, Antoine; Terrill, Eric.
Sea ice inhibits the development of wind‐generated surface gravity waves which are the dominant factor in upper ocean mixing and air‐sea fluxes. In turn, sea ice properties are modified by wave action. Understanding the interaction of ice and waves is important for characterizing both air‐sea interactions and sea ice dynamics. Current leading theory attributes wave attenuation primarily to scattering by ice floes. Here we use new in situ wave measurements to show that attenuation is dominated by dissipation with negligible effect by scattering. Time series of wave height in ice exhibit an ``on/off" behavior that is consistent with switching between two states of sea ice; a relatively unbroken state associated with strong damping (off), possibly caused by...
Tipo: Text Palavras-chave: Sea ice<; /AUTHOR_KEYWORD>; Ocean waves<; /AUTHOR_KEYWORD>; SAR<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00632/74435/74156.pdf
Imagem não selecionada

Imprime registro no formato completo
Ironing Out Fe Residence Time in the Dynamic Upper Ocean ArchiMer
Black, Ee; Kienast, Ss; Lemaitre, N; Lam, Pj; Anderson, Rf; Planquette, Helene; Planchon, Frederic; Buesseler, Ko.
Although iron availability has been shown to limit ocean productivity and influence marine carbon cycling, the rates of processes driving iron's removal and retention in the upper ocean are poorly constrained. Using 234Th‐ and sediment‐trap data, most of which were collected through international GEOTRACES efforts, we perform an unprecedented observation‐based assessment of iron export from and residence time in the upper ocean. The majority of these new residence time estimates for total iron in the surface ocean (0‐250 m) fall between 10 and 100 days. The upper ocean residence time of dissolved iron, on the other hand, varies and cycles on sub‐annual to annual timescales. Collectively, these residence times are shorter than previously thought, and the...
Tipo: Text Palavras-chave: Thorium-234<; /AUTHOR_KEYWORD>; Iron<; /AUTHOR_KEYWORD>; Export<; /AUTHOR_KEYWORD>; GEOTRACES<; /AUTHOR_KEYWORD>; Residence time<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00644/75632/76493.pdf
Imagem não selecionada

Imprime registro no formato completo
Physical mechanisms driving oxygen subduction in the global ocean ArchiMer
Portela, Esther; Kolodziejczyk, Nicolas; Vic, Clement; Thierry, Virginie.
Future changes in subduction are suspected to be critical for the ocean deoxygenation predicted by climate models over the 21st century. However, the drivers of global oxygen subduction have not been fully described or quantified. Here, we address the physical mechanisms responsible for the oxygen transport across the late winter mixed layer base and their relation with water‐mass formation. Up to 70% of the global oxygen uptake takes place during Mode Water subduction mostly in the Southern Ocean and the North Atlantic. Te driving mechanisms are (i) the combination of strong currents with large mixed‐layer‐depth gradients at localized hotspots and (ii) the wind‐driven vertical velocity within the Subtropical gyres. Oxygen diffusion, despite being...
Tipo: Text Palavras-chave: Oxygen subduction<; /AUTHOR_KEYWORD>; Ocean ventilation<; /AUTHOR_KEYWORD>; Mode waters<; /AUTHOR_KEYWORD>; Oxygen difussion<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00645/75670/76537.pdf
Registros recuperados: 7
Primeira ... 1 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional