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	Provedor de dados ArchiMer (4) Autor Arzel, Olivier (3) Huck, Thierry (3) Colin De Verdiere, Alain (1) Gaillard, Fabienne (1) Holliday, N. Penny (1) Hughes, Sarah L. (1) Sevellec, Florian (1) Mais... Palavra-chave Multidecadal variability (4) Climate variability (2) Instability (2) Meridional overturning circulation (2) Rossby waves (2) Circulation (1) Circulation/ Dynamics (1) Interdecadal variability (1) North Atlantic (1) North Atlantic Oscillation (1) Ocean circulation (1) Planetary waves (1) Salinity (1) Temperature (1) Turbulence (1) Variability (1) Mais... Tipo do documento Text (4) Ano 2020 (1) 2018 (1) 2015 (1) 2012 (1) País France (4) Idioma Inglês (4)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 4 Primeira ... 1 ... Última Contributions of Atmospheric Stochastic Forcing and Intrinsic Ocean Modes to North Atlantic Ocean Interdecadal Variability ArchiMer Arzel, Olivier; Huck, Thierry. Atmospheric stochastic forcing associated with the North Atlantic Oscillation (NAO) and intrinsic ocean modes associated with the large-scale baroclinic instability of the North Atlantic Current (NAC) are recognized as two strong paradigms for the existence of the Atlantic Multidecadal Oscillation (AMO). The degree to which each of these factors contribute to the low-frequency variability of the North Atlantic is the central question in this paper. This issue is addressed here using an ocean general circulation model run under a wide range of background conditions extending from a super-critical regime where the oceanic variability spontaneously develops in the absence of any atmospheric noise forcing to a damped regime where the variability requires some... Tipo: Text Palavras-chave: Instability; Rossby waves; Climate variability; Interdecadal variability; Multidecadal variability; North Atlantic Oscillation. Ano: 2020 URL: https://archimer.ifremer.fr/doc/00599/71138/69452.pdf Multidecadal variability of the overturning circulation in presence of eddy turbulence ArchiMer Huck, Thierry; Arzel, Olivier; Sevellec, Florian. At low-resolution, idealized ocean circulation models forced by prescribed differential surface heat fluxes show spontaneous multidecadal variability depending critically on eddy diffusivity coefficients. The existence of this critical threshold in the range of observational estimates legitimates some doubt on the relevance of such intrinsic oscillations in the real ocean. Through a series of numerical simulations with increasing resolution up to eddy-resolving ones (10 km) and various diapycnal diffusivities, this multidecadal variability proves a generic ubiquitous feature, at least in model versions with a flat bottom. The mean circulation largely changes in the process of refining the horizontal grid (along with the associated implicit viscosity and... Tipo: Text Palavras-chave: Circulation/ Dynamics; Meridional overturning circulation; Rossby waves; Turbulence; Variability; Multidecadal variability. Ano: 2015 URL: http://archimer.ifremer.fr/doc/00251/36243/34798.pdf Variability in the ICES/NAFO region between 1950 and 2009: observations from the ICES Report on Ocean Climate ArchiMer Hughes, Sarah L.; Holliday, N. Penny; Gaillard, Fabienne. The ICES Report on Ocean Climate presents the latest information on the status and trends of sea temperature and salinity in the North Atlantic and Nordic Seas. It is the main product of the ICES Working Group on Oceanic Hydrography, published annually. Bringing together multiple time-series from across the ICES and NAFO regions offers insight into the concurrent spatial and temporal trends in ocean temperature and salinity. This paper presents an overview of the physical variability in the North Atlantic Ocean at decadal and longer time-scales and reviews the current state of understanding of the causes and mechanisms of this variability. Between the 1960s and the 1990s, the North Atlantic Oscillation (NAO) index increased from a persistent negative phase... Tipo: Text Palavras-chave: Circulation; Multidecadal variability; North Atlantic; Salinity; Temperature. Ano: 2012 URL: http://archimer.ifremer.fr/doc/00087/19854/17513.pdf The Internal Generation of the Atlantic Ocean Interdecadal Variability ArchiMer Arzel, Olivier; Huck, Thierry; Colin De Verdiere, Alain. Numerical simulations of a realistic ocean general circulation model forced by prescribed surface fluxes are used to study the origin and structure of intrinsic interdecadal variability of the ocean circulation. When eddy-induced turbulent diffusivities are low enough, spontaneous oscillations of the Atlantic meridional overturning circulation (AMOC) with periods O(20) yr and amplitude O(1) Sv (1 Sv ≡ 106 m3 s−1) emerge. The transition from the steady to the oscillatory regime is shown to be consistent with a supercritical Hopf bifurcation of the horizontal Peclet number. Adding atmospheric thermal damping is shown to have a very limited influence on the domain of existence of intrinsic variability. The spatial structure of the mode consists of a dipole of... Tipo: Text Palavras-chave: Instability; Meridional overturning circulation; Ocean circulation; Planetary waves; Climate variability; Multidecadal variability. Ano: 2018 URL: https://archimer.ifremer.fr/doc/00464/57522/59708.pdf Registros recuperados: 4 Primeira ... 1 ... Última

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