Consulta: creatorFacets:"Klein, Patrice"
Registros recuperados: 67
Data/hora: 10/06/2024 07:46:01

Impact of the small-scale elongated filaments on the oceanic vertical pump
Provedor de dados: 5
Autores: Lapeyre, Guillaume; Klein, Patrice.
Oceanic mesoscale eddies (with a diameter of 50-100 km) are known to be associated with significant vertical tracer fluxes in the upper few hundred meters. In particular, they are important for the biogeochemical system, accounting for 20-30% of the vertical nutrient transport. However, estimates of the global tracer fluxes neglect the role played by thin elongated filaments (with a width of 5-10 km). These sub-mesoscale structures are produced by eddy interactions and ubiquitous in regions between eddies. We use a Surface Quasi-Geostrophic model to quantify their impact on the net vertical tracer flux into the surface layers. We show that eddy interactions are an important source of tracer injection because they lead to the production of filaments and to...
Tipo: Text
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2459.pdf

Wind ringing of the ocean in presence of mesoscale eddies
Provedor de dados: 5
Autores: Klein, Patrice; Lapeyre, Guillaume; Large, Wg.
Recent findings have highlighted the impact of high frequency (HF) winds on the inertial motions and the consequences on the large-scale oceanic circulation [Wunsch and Ferrari, 2004]. Within this context the present study focuses on the role of intermediate scales related to oceanic mesoscale eddies. Results show that a turbulent eddy field does not affect the impact of HF winds on the inertial motions. However the eddies efficiently and permanently concentrate the wind-forced inertial motions in small-scale anticyclonic structures. This leads to a spatially heterogeneous vertical mixing strongly related to the eddy field properties.
Tipo: Text
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00000/10838/9262.pdf

Altimetry-Based Diagnosis of Deep-Reaching Sub-Mesoscale Ocean Fronts
Provedor de dados: 5
Autores: Siegelman, Lia; Klein, Patrice; Thompson, Andrew F.; Torres, Hector S.; Menemenlis, Dimitris.
Recent studies demonstrate that energetic sub-mesoscale fronts (10–50 km width) extend in the ocean interior, driving large vertical velocities and associated fluxes. However, diagnosing the dynamics of these deep-reaching fronts from in situ observations remains challenging because of the lack of information on the 3-D structure of the horizontal velocity. Here, a realistic numerical simulation in the Antarctic Circumpolar Current (ACC) is used to study the dynamics of submesocale fronts in relation to velocity gradients, responsible for the formation of these fronts. Results highlight that the stirring properties of the flow at depth, which are related to the velocity gradients, can be inferred from finite-size Lyapunov exponent (FSLE) at the surface....
Tipo: Text
Palavras-chave: Altimetry; Finite-size Lyapunov exponent; Ocean dynamics; Sub-mesoscale.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00645/75666/76532.pdf

Deep ocean inertia-gravity waves simulated in a high-resolution global coupled atmosphere-ocean GCM - art. no. L04610
Provedor de dados: 5
Autores: Komori, N; Ohfuchi, W; Taguchi, B; Sasaki, H; Klein, Patrice.
In order to investigate the deep ocean inertia-gravity waves, a high-resolution global coupled atmosphere-ocean simulation is carried out with a coupling interval of 20 minutes. Large (similar to 10(-3) m s(-1)) root-mean-square variability of vertical velocity is found in middepths (2000-4000 m), which is not reported in previous studies using realistic ocean simulations. Horizontal distribution of the large variability roughly corresponds to the wintertime atmospheric storm tracks and is stretched equatorward due to beta-dispersion in open ocean with some "shadow regions'' behind the obstacles. Frequency spectrum of vertical velocity has strong peaks at around f and 2f (f is the local inertial period) in midlatitudes, and has additional peak at around...
Tipo: Text
Palavras-chave: Coupled atmosphere ocean model; Deep ocean; Inertia gravity wave.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3825.pdf

Surface Roughness Imaging of Currents Shows Divergence and Strain in the Wind Direction
Provedor de dados: 5
Autores: Rascle, Nicolas; Chapron, Bertrand; Ponte, Aurelien; Ardhuin, Fabrice; Klein, Patrice.
Images of sea surface roughness-for example, obtained by synthetic aperture radars (SAR) or by radiometers viewing areas in and around the sun glitter-at times provide clear observations of meso- and sub-mesoscale oceanic features. Interacting with the surface wind waves, particular deformation properties of surface currents are responsible for those manifestations. Ignoring other sources of surface roughness variations, the authors limit their discussion to the mean square slope (mss) variability. This study confirms that vortical currents and currents with shear in the wind direction shall not be expressed in surface roughness images. Only divergent currents or currents with no divergence but strained in the wind direction can exhibit surface roughness...
Tipo: Text
Palavras-chave: Circulation/ Dynamics; Ageostrophic circulations; Atmosphere-ocean interaction; Mesoscale processes; Wind waves; Atm/Ocean Structure/ Phenomena; Boundary layer; Sea state.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00210/32170/30619.pdf

Characterization of tracer cascade in physical space
Provedor de dados: 5
Autores: Hua, Bach-lien; Klein, Patrice; Lapeyre, Guillaume.
Geophysical turbulent fluids are characterized by the presence of organized energetic structures which control tracer transport and stirring, while enabling a tracer cascade down to the smallest scales. In order to understand the physical mechanisms involved in this turbulent tracer cascade, we focus on the dynamics underlying the formation of tracer gradients which are necessarily associated to this cascade. We show that the dynamics of tracer gradients in physical space is mainly governed by their orientation with respect to the compressional eigenvector of the strain tensor. This relative angle results from the competition between strain and the "effective rotation" (due to both vorticity and rotation of strain axes). The implication is that tracer...
Tipo: Text
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00067/17786/15309.pdf

Submesoscale transition from geostrophic flows to internal waves in the northwestern Pacific upper ocean
Provedor de dados: 5
Autores: Qiu, Bo; Nakano, Toshiya; Chen, Shuiming; Klein, Patrice.
With radar interferometry, the next-generation Surface Water and Ocean Topography satellite mission will improve the measured sea surface height resolution down to 15 km, allowing us to investigate for the first time the global upper ocean variability at the submesoscale range. Here, by analysing shipboard Acoustic Doppler Current Profiler measurements along 137 degrees E in the northwest Pacific of 2004-2016, we show that the observed upper ocean velocities are comprised of balanced geostrophic flows and unbalanced internal waves. The transition length scale, L-t, separating these two motions, is found to depend strongly on the energy level of local mesoscale eddy variability. In the eddy-abundant western boundary current region of Kuroshio, L-t can be...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00368/47935/47962.pdf

A simulation of the effects of air-sea transfer variability on the structure of marine upper layers
Provedor de dados: 5
Autores: Klein, Patrice.
A rather simple one-dimensional unsteady model similar to Mellor and Durbin (1975) is used to study the effects of the time variability of meteorological inputs on the evolution of the thermal stratification of marine upper layers. The physical implications of such a model are discussed, particularly with respect to the results obtained in a number of typical situations. The thermal structure of the marine upper layers in the Gulf of Lion during the COFRASOY II expedition was also simulated. Although the model is not able to reproduce all details of the marine environment, the mixed-layer deepening and sea surface temperature are predicted rather well from the known meteorological parameters. It appears in conclusion that the most important...
Tipo: Text
Ano: 1980
URL: http://archimer.ifremer.fr/doc/00254/36570/35124.pdf

Spontaneous inertia-gravity-wave generation by surface-intensified turbulence
Provedor de dados: 5
Autores: Danioux, Eric; Vanneste, J.; Klein, Patrice; Sasaki, H.
The spontaneous generation of inertia-gravity waves (IGWs) by surface-intensified, nearly balanced motion is examined using a high-resolution simulation of the primitive equations in an idealized oceanic configuration. At large scale and mesoscale, the dynamics, which is driven by baroclinic instability near the surface, is balanced and qualitatively well described by the surface quasi-geostrophic model. This however predicts an increase of the Rossby number with decreasing spatial scales and, hence, a breakdown of balance at small scale; the generation of IGWs is a consequence of this breakdown. The wave field is analysed away from the surface, at depths where the associated vertical velocities are of the same order as those associated with the balanced...
Tipo: Text
Palavras-chave: Internal waves; Quasi-geostrophic flows; Wave-turbulence interactions.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00083/19437/17389.pdf

Using High-Resolution Altimetry to Observe Mesoscale Signals
Provedor de dados: 5
Autores: Pujol, M-i; Dibarboure, G.; Le Traon, Pierre-yves; Klein, Patrice.
An Ocean System Simulation Experiment is used to quantify the observing capability of the Surface Water and Ocean Topography (SWOT) mission and its contribution to higher-quality reconstructed sea level anomaly (SLA) fields using optimal interpolation. The paper focuses on the potential of SWOT for mesoscale observation (wavelengths larger than 100 km and time periods larger than 10 days) and its ability to replace or complement altimetry for classical mesoscale applications. For mesoscale variability, the wide swath from SWOT provides an unprecedented sampling capability. SWOT alone would enable the regional surface signal reconstruction as precisely as a four-altimeter constellation would, in regions where temporal sampling is optimum. For some specifics...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00101/21192/18818.pdf

Effects of an asymmetric friction on the nonlinear equilibration of a baroclinic system
Provedor de dados: 5
Autores: Riviere, Pascal; Klein, Patrice.
Following some recent linear and nonlinear studies the authors examine, using numerical simulations of a classical two-layer model, the effect of an asymmetric friction on the nonlinear equilibrium of moderately unstable baroclinic systems, The results show that the presence of an asymmetric friction leads to a significant wave scale selection: ''long'' waves (in terms of their zonal wavelengths) emerge with a traditional asymmetric friction (with the upper layer less viscous than the lower layer), while only ''short'' waves dominate with a nontraditional asymmetric friction (with the lower layer less viscous than the upper layer). The role of the nonlinear interactions and. more precisely, the effects of an asymmetric friction on the wave-mean flow and...
Tipo: Text
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00336/44705/44915.pdf

Seasonal Mesoscale and Submesoscale Eddy Variability along the North Pacific Subtropical Countercurrent
Provedor de dados: 5
Autores: Qiu, Bo; Chen, Shuiming; Klein, Patrice; Sasaki, Hideharu; Sasai, Yoshikazu.
Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1/30 degrees high-resolution OGCM simulation and a gridded satellite altimetry product are analyzed to contrast the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of &gt;150 km, the altimetry product reveals that the STCC eddy kinetic energy and rms vorticity have a seasonal maximum in May and April, respectively, a weak positive vorticity skewness without seasonal dependence, and an inverse (forward) kinetic energy cascade for wavelengths larger (shorter) than 250 km. In contrast, the...
Tipo: Text
Palavras-chave: Circulation/ Dynamics; Eddies; Instability; Mesoscale processes; Observational techniques and algorithms; Altimetry; Models and modeling; Ocean models; Variability; Seasonal variability.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00245/35588/34142.pdf

Impact of sub-mesoscale physics on production and subduction of phytoplankton in an oligotrophic regime
Provedor de dados: 5
Autores: Levy, Marina; Klein, Patrice; Treguier, Anne-marie.
Using a protocol of numerical experiments where horizontal resolution is progressively increased, we show that small-scale (or sub-mesoscale) physics has a strong impact on both mesoscale physics and phytoplankton production/subduction.Mesoscale and sub-mesoscale physics result from the nonlinear equilibration of an unstable baroclinic jet. The biogeochemical context is oligotrophy. The explicitly resolved sub-mesoscales, at least smaller than one fifth of the internal Rossby radius of deformation, reinforce the mesoscale eddy field and contribute to double the primary production and phytoplankton subduction budgets. This enhancement is due to the reinforced mesoscale physics and is also achieved by the small-scale frontal dynamics. This sub-mesoscale...
Tipo: Text
Palavras-chave: Oligotrophy; Phytoplankton production; Vorticity gradient; Eddy field; Mesoscale physics.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-800.pdf

Estimation of the Agulhas ring impacts on meridional heat fluxes and transport using ARGO floats and satellite data
Provedor de dados: 5
Autores: Azevedo Correia, Joao Marcos; De Boyer Montegut, Clement; Cabanes, Cecile; Klein, Patrice.
A method that combines vertical profiles from the ARGO floats program and satellite Sea Surface Height (SSH) data is used to reconstruct the vertical structure of the Agulhas rings. All eddies shed by the Agulhas retroflection in the period between January 2005 and December 2008 were successfully reconstructed. The velocity structures obtained are tilted and phase shifted in relation to the temperature anomalies, resulting in an annual mean eddy meridional heat flux across the ring paths of 0.062 +/- 0.012 PW (northward). A first order estimate indicates 0.07 PW entering the Atlantic from the Indian Ocean through Agulhas rings. The volume transport by Agulhas rings is believed to play a central role in the overturning circulation, being the main process...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00051/16221/13746.pdf

Partitioning ocean motions into balanced motions and internal gravity waves: A modeling study in anticipation of future space missions
Provedor de dados: 5
Autores: Torres, Hector S.; Klein, Patrice; Menemenlis, Dimitris; Qiu, Bo; Su, Zhan; Wang, Jinbo; Chen, Shuiming; Fu, Lee-lueng.
Internal gravity waves (IGWs) and balanced motions (BMs) with scales &lt; 100‐km capture most of the vertical velocity field in the upper ocean. They have, however, different impacts on the ocean energy budget, which explains the need to partition motions into BMs and IGWs. One way is to exploit the synergy of using different satellite observations, the only observations with global coverage and a reasonable spatial and temporal resolution. But we need first to characterize and understand their signatures on the different surface oceanic fields. This study addresses this issue by using an ocean global numerical simulation with high‐resolution (1/48o). Our methodology is based on the analysis of the 12,000 frequency‐wavenumber spectra to discriminate these...
Tipo: Text
Palavras-chave: Oceanic surface motions; Satellite observations; Balanced motions; Internal gravity waves.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00464/57568/59746.pdf

Atmospheric response to sea surface temperature mesoscale structures
Provedor de dados: 5
Autores: Lambaerts, J.; Lapeyre, Guillaume; Plougonven, R.; Klein, Patrice.
Recent studies have revealed that strong sea surface temperature (SST) fronts, on the scale of a Western Boundary Current, significantly affect not just the Marine Boundary Layer but the entire troposphere. This has aroused renewed interest in air-sea interactions. The present study investigates the atmospheric response to fixed SST anomalies associated with mesoscale oceanic eddies and submesoscale filaments, using idealized simulations. Our main result is that in weak wind conditions, the vertical velocity in the planetary boundary layer (PBL) is linearly proportional to the SST Laplacian. This is established by a quantitative analysis in the spatial space as well as in the spectral space. Comparing the responses to two different SST fields shows that...
Tipo: Text
Palavras-chave: Air-sea interactions; Boundary layer; Sea surface temperature.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00169/28047/26247.pdf

Incoherent signature of internal tides on sea level in idealized numerical simulations
Provedor de dados: 5
Autores: Ponte, Aurelien; Klein, Patrice.
The non persistent phase relationship between internal tides and astronomical forcings, also known as incoherence, has been identified as a major question in the context of future wide-swath satellite altimetry. This study addresses this issue using a novel set of numerical experiments where a plane-wave/low-mode internal tide propagates through a turbulent mesoscale eddy field. These experiments demonstrate the emergence of internal tide incoherence as the eddy turbulence is strengthened. In strongly turbulent situations, the internal tide signature on sea level forms complex interference patterns with large amplifications of the initial internal wave. These patterns evolve more rapidly than the signature of the turbulent eddy field on sea level. The...
Tipo: Text
Palavras-chave: Internal tide; Wide-swath altimetry; Mesoscale turbulence; Incoherence.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00254/36571/35109.pdf

Impact of Small-scale Structures on Two Energetic Dynamical Oceanic Regimes (2007)
Provedor de dados: 5
Autores: Klein, Patrice; Hua, Bach-lien; Le Gentil, Sylvie; Fruman, Mark; Menesguen, Claire; Sasaki, Hideharu.
The big challenge of the next decade for the oceanic sciences is to adopt a multi-scale approach because of the strong nonlinearity of the oceanic fluid. This can be undertaken only through numerical simulations with ultra-high resolution. Within this context, the purpose of our project is to fully explore two energetic dynamical oceanic regimes that have a major impact on the general oceanic circulation: the mesoscale eddy regime at mid-latitudes and the equatorial regime. Results will help for the configuration of realistic numerical simulations to be performed in 2007-2008 by the OFES group on the Earth Simulator and also should benefit to future climate models. These studies make use of the Primitive Equations model ROMS (Regional Ocean Modelling...
Tipo: Text
Palavras-chave: Mesoscale oceanic eddies; Equatorial dynamics.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00067/17784/15307.pdf

SEASTAR: A Mission to Study Ocean Submesoscale Dynamics and Small-Scale Atmosphere-Ocean Processes in Coastal, Shelf and Polar Seas
Provedor de dados: 5
Autores: Gommenginger, Christine; Chapron, Bertrand; Hogg, Andy; Buckingham, Christian; Fox-kemper, Baylor; Eriksson, Leif; Soulat, Francois; Ubelmann, Clément; Ocampo-torres, Francisco; Nardelli, Bruno Buongiorno; Griffin, David; Lopez-dekker, Paco; Knudsen, Per; Andersen, Ole; Stenseng, Lars; Stapleton, Neil; Perrie, William; Violante-carvalho, Nelson; Schulz-stellenfleth, Johannes; Woolf, David; Isern-fontanet, Jordi; Ardhuin, Fabrice; Klein, Patrice; Mouche, Alexis; Pascual, Ananda; Capet, Xavier; Hauser, Daniele; Stoffelen, Ad; Morrow, Rosemary; Aouf, Lotfi; Breivik, Øyvind; Fu, Lee-lueng; Johannessen, Johnny A.; Aksenov, Yevgeny; Bricheno, Lucy; Hirschi, Joel; Martin, Adrien Ch; Martin, Adiran P; Nurser, George; Polton, Jeff; Wolf, Judith; Johnsen, Harald; Soloviev, Alexander; Jacobs, Gregg A.; Collard, Fabrice; Groom, Steve; Kudryavtsev, Vladimir; Wilkin, John; Navarro, Victor; Babanin, Alex; Martin, Matthew; Siddorn, John; Saulter, Andrew; Rippeth, Tom; Emery, Bill; Maximenko, Nikolai; Romeiser, Roland; Graber, Hans; Azcarate, Aida Alvera; Hughes, Chris W.; Vandemark, Doug; Silva, Jose Da; Leeuwen, Peter Jan Van; Naveira-garabato, Alberto; Gemmrich, Johannes; Mahadevan, Amala; Marquez, Jose; Munro, Yvonne; Doody, Sam; Burbidge, Geoff.
High-resolution satellite images of ocean color and sea surface temperature reveal an abundance of ocean fronts, vortices and filaments at scales below 10 km but measurements of ocean surface dynamics at these scales are rare. There is increasing recognition of the role played by small scale ocean processes in ocean-atmosphere coupling, upper-ocean mixing and ocean vertical transports, with advanced numerical models and in situ observations highlighting fundamental changes in dynamics when scales reach 1 km. Numerous scientific publications highlight the global impact of small oceanic scales on marine ecosystems, operational forecasts and long-term climate projections through strong ageostrophic circulations, large vertical ocean velocities and mixed layer...
Tipo: Text
Palavras-chave: Satellite; Air sea interactions; Upper ocean dynamics; Submesoscale; Coastal; Marginal ice zone; Radar; Along-track interferometry.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00510/62121/66325.pdf

Three-dimensional reconstruction of oceanic mesoscale currents from surface information - art. no. C09005
Provedor de dados: 5
Autores: Isern-fontanet, Jordi; Lapeyre, Guillaume; Klein, Patrice; Chapron, Bertrand; Hecht, M.
The ability to reconstruct the three-dimensional (3D) dynamics of the ocean by an effective version of Surface Quasi-Geostrophy (eSQG) is examined. Using the fact that surface density plays an analogous role as interior potential vorticity (PV), the eSQG method consists in inverting the QG PV generated by sea-surface density only. We also make the extra assumption that sea-surface temperature (SST) anomalies fully represent surface density anomalies. This approach requires a single snapshot of SST and the setup of two parameters: the mean Brunt-Vaisala frequency and a parameter that determines the energy level at the ocean surface. The validity of this approach is tested using an Ocean General Circulation Model simulation representing the North Atlantic in...
Tipo: Text
Palavras-chave: 3D dynamics reconstruction; SST; Surface Quasi Geostrophy.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4620.pdf

Inertial Resonance Induced by an Oceanic Jet
Provedor de dados: 5
Autores: Klein, Patrice; Treguier, Anne-marie.
The dynamics of the mixed layer in the presence of an embedded geostrophic jet has been investigated using a simple 1 1/2-layer model and a two-dimensional primitive equation model. The jet vorticity induces a spatial variability of the wind-driven inertial motions that can have some important consequences on the mixed-layer dynamics. With a steady wind stress parallel to the front. the main effect is the generation of steady upwellings and downwellings due to the divergence of the mean Ekman drift (as reported by Niiler). With a cross-front wind, however, a dramatic exponential amplification of the inertial oscillations caused by an inertial resonance mechanism is found: this mechanism can increase the inertial waves amplitude by a factor up to 10 within...
Tipo: Text
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00192/30369/29050.pdf

Horizontal dispersion of near-inertial oscillations in a turbulent mesoscale eddy field
Provedor de dados: 5
Autores: Klein, Patrice; Smith, Stefan Llewellyn.
We study the dispersion of wind-induced near-inertial oscillations (NIOs) in a fully turbulent baroclinic mesoscale eddy field characterized by a continuous wavenumber spectrum. The influence of the eddy field on the horizontal dispersion of the different NIO modes is analyzed using a vertical normal mode expansion. Previous studies have identified two dispersion regimes: trapping and strong dispersion. We examine the modes in physical and spectral space to assess which regime prevails,Numerical and analytical results show the prevalence of a trapping regime. For each NIO mode, there exists a critical horizontal wavenumber. k(c), that separates large-scale NIO structures, where trapping dominates, from the much less energetic small-scale NIO structures,...
Tipo: Text
Palavras-chave: Refraction; Horizontal dispersion; Wind induced oscillations; Eddy field.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/2001/publication-799.pdf

Altimetry for the future: Building on 25 years of progress
Provedor de dados: 5
Autores: Abdalla, Saleh; Abdeh Kolahchi, Abdolnabi; Adusumilli, Susheel; Aich Bhowmick, Suchandra; Alou-font, Eva; Amarouche, Laiba; Andersen, Ole Baltazar; Antich, Helena; Aouf, Lotfi; Arbic, Brian; Armitage, Thomas; Arnault, Sabine; Artana, Camila; Aulicino, Giuseppe; Ayoub, Nadia; Badulin, Sergei; Baker, Steven; Banks, Chris; Bao, Lifeng; Barbetta, Silvia; Barceló-llull, Bàrbara; Barlier, François; Basu, Sujit; Bauer-gottwein, Peter; Becker, Matthias; Beckley, Brian; Bellefond, Nicole; Belonenko, Tatyana; Benkiran, Mounir; Benkouider, Touati; Bennartz, Ralf; Benveniste, Jérôme; Bercher, Nicolas; Berge-nguyen, Muriel; Bettencourt, Joao; Blarel, Fabien; Blazquez, Alejandro; Blumstein, Denis; Bonnefond, Pascal; Borde, Franck; Bouffard, Jérôme; Boy, François; Boy, Jean-paul; Brachet, Cédric; Brasseur, Pierre; Braun, Alexander; Brocca, Luca; Brockley, David; Brodeau, Laurent; Brown, Shannon; Bruinsma, Sean; Bulczak, Anna; Buzzard, Sammie; Cahill, Madeleine; Calmant, Stéphane; Calzas, Michel; Camici, Stefania; Cancet, Mathilde; Capdeville, Hugues; Carabajal, Claudia Cristina; Carrere, Loren; Cazenave, Anny; Chassignet, Eric P.; Chauhan, Prakash; Cherchali, Selma; Chereskin, Teresa; Cheymol, Cecile; Ciani, Daniele; Cipollini, Paolo; Cirillo, Francesca; Cosme, Emmanuel; Coss, Steve; Cotroneo, Yuri; Cotton, David; Couhert, Alexandre; Coutin-faye, Sophie; Crétaux, Jean-françois; Cyr, Frederic; D’ovidio, Francesco; Darrozes, José; David, Cedric; Dayoub, Nadim; De Staerke, Danielle; Deng, Xiaoli; Desai, Shailen; Desjonqueres, Jean-damien; Dettmering, Denise; Di Bella, Alessandro; Díaz-barroso, Lara; Dibarboure, Gerald; Dieng, Habib Boubacar; Dinardo, Salvatore; Dobslaw, Henryk; Dodet, Guillaume; Doglioli, Andrea; Domeneghetti, Alessio; Donahue, David; Dong, Shenfu; Donlon, Craig; Dorandeu, Joël; Drezen, Christine; Drinkwater, Mark; Du Penhoat, Yves; Dushaw, Brian; Egido, Alejandro; Erofeeva, Svetlana; Escudier, Philippe; Esselborn, Saskia; Exertier, Pierre; Fablet, Ronan; Falco, Cédric; Farrell, Sinead Louise; Faugere, Yannice; Femenias, Pierre; Fenoglio, Luciana; Fernandes, Joana; Fernández, Juan Gabriel; Ferrage, Pascale; Ferrari, Ramiro; Fichen, Lionel; Filippucci, Paolo; Flampouris, Stylianos; Fleury, Sara; Fornari, Marco; Forsberg, Rene; Frappart, Frédéric; Frery, Marie-laure; Garcia, Pablo; Garcia-mondejar, Albert; Gaudelli, Julia; Gaultier, Lucile; Getirana, Augusto; Gibert, Ferran; Gil, Artur; Gilbert, Lin; Gille, Sarah; Giulicchi, Luisella; Gómez-enri, Jesús; Gómez-navarro, Laura; Gommenginger, Christine; Gourdeau, Lionel; Griffin, David; Groh, Andreas; Guerin, Alexandre; Guerrero, Raul; Guinle, Thierry; Gupta, Praveen; Gutknecht, Benjamin D.; Hamon, Mathieu; Han, Guoqi; Hauser, Danièle; Helm, Veit; Hendricks, Stefan; Hernandez, Fabrice; Hogg, Anna; Horwath, Martin; Idžanović, Martina; Janssen, Peter; Jeansou, Eric; Jia, Yongjun; Jia, Yuanyuan; Jiang, Liguang; Johannessen, Johnny A.; Kamachi, Masafumi; Karimova, Svetlana; Kelly, Kathryn; Kim, Sung Yong; King, Robert; Kittel, Cecile M.m.; Klein, Patrice; Klos, Anna; Knudsen, Per; Koenig, Rolf; Kostianoy, Andrey; Kouraev, Alexei; Kumar, Raj; Labroue, Sylvie; Lago, Loreley Selene; Lambin, Juliette; Lasson, Léa; Laurain, Olivier; Laxenaire, Rémi; Lázaro, Clara; Le Gac, Sophie; Le Sommer, Julien; Le Traon, Pierre-yves; Lebedev, Sergey; Léger, Fabien; Legresy, Benoı̂t; Lemoine, Frank; Lenain, Luc; Leuliette, Eric; Levy, Marina; Lillibridge, John; Liu, Jianqiang; Llovel, William; Lyard, Florent; Macintosh, Claire; Makhoul Varona, Eduard; Manfredi, Cécile; Marin, Frédéric; Mason, Evan; Massari, Christian; Mavrocordatos, Constantin; Maximenko, Nikolai; Mcmillan, Malcolm; Medina, Thierry; Melet, Angelique; Meloni, Marco; Mertikas, Stelios; Metref, Sammy; Meyssignac, Benoit; Michaël, Ablain; Minster, Jean-françois; Moreau, Thomas; Moreira, Daniel; Morel, Yves; Morrow, Rosemary; Moyard, John; Mulet, Sandrine; Naeije, Marc; Nerem, Robert Steven; Ngodock, Hans; Nielsen, Karina; Nilsen, Jan Even Øie; Niño, Fernando; Nogueira Loddo, Carolina; Noûs, Camille; Obligis, Estelle; Otosaka, Inès; Otten, Michiel; Oztunali Ozbahceci, Berguzar; P. Raj, Roshin; Paiva, Rodrigo; Paniagua, Guillermina; Paolo, Fernando; Paris, Adrien; Pascual, Ananda; Passaro, Marcello; Paul, Stephan; Pavelsky, Tamlin; Pearson, Christopher; Penduff, Thierry; Peng, Fukai; Perosanz, Felix; Picot, Nicolas; Piras, Fanny; Poggiali, Valerio; Poirier, Étienne; Ponce De León, Sonia; Prants, Sergey; Prigent, Catherine; Provost, Christine; Pujol, M-isabelle; Qiu, Bo; Quilfen, Yves; Rami, Ali; Raney, R. Keith; Raynal, Matthias; Remy, Elisabeth; Rémy, Frédérique; Restano, Marco; Richardson, Annie; Richardson, Donald; Ricker, Robert; Ricko, Martina; Rinne, Eero; Rose, Stine Kildegaard; Rosmorduc, Vinca; Rudenko, Sergei; Ruiz, Simón; Ryan, Barbara J.; Salaün, Corinne; Sanchez-roman, Antonio; Sandberg Sørensen, Louise; Sandwell, David; Saraceno, Martin; Scagliola, Michele; Schaeffer, Philippe; Scharffenberg, Martin G.; Scharroo, Remko; Schiller, Andreas; Schneider, Raphael; Schwatke, Christian; Scozzari, Andrea; Ser-giacomi, Enrico; Seyler, Frederique; Shah, Rashmi; Sharma, Rashmi; Shaw, Andrew; Shepherd, Andrew; Shriver, Jay; Shum, C.k.; Simons, Wim; Simonsen, Sebatian B.; Slater, Thomas; Smith, Walter; Soares, Saulo; Sokolovskiy, Mikhail; Soudarin, Laurent; Spatar, Ciprian; Speich, Sabrina; Srinivasan, Margaret; Srokosz, Meric; Stanev, Emil; Staneva, Joanna; Steunou, Nathalie; Stroeve, Julienne; Su, Bob; Sulistioadi, Yohanes Budi; Swain, Debadatta; Sylvestre-baron, Annick; Taburet, Nicolas; Tailleux, Rémi; Takayama, Katsumi; Tapley, Byron; Tarpanelli, Angelica; Tavernier, Gilles; Testut, Laurent; Thakur, Praveen K.; Thibaut, Pierre; Thompson, Luanne; Tintoré, Joaquín; Tison, Céline; Tourain, Cédric; Tournadre, Jean; Townsend, Bill; Tran, Ngan; Trilles, Sébastien; Tsamados, Michel; Tseng, Kuo-hsin; Ubelmann, Clément; Uebbing, Bernd; Vergara, Oscar; Verron, Jacques; Vieira, Telmo; Vignudelli, Stefano; Vinogradova Shiffer, Nadya; Visser, Pieter; Vivier, Frederic; Volkov, Denis; Von Schuckmann, Karina; Vuglinskii, Valerii; Vuilleumier, Pierrik; Walter, Blake; Wang, Jida; Wang, Chao; Watson, Christopher; Wilkin, John; Willis, Josh; Wilson, Hilary; Woodworth, Philip; Yang, Kehan; Yao, Fangfang; Zaharia, Raymond; Zakharova, Elena; Zaron, Edward D.; Zhang, Yongsheng; Zhao, Zhongxiang; Zinchenko, Vadim; Zlotnicki, Victor.
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and...
Tipo: Text
Palavras-chave: Satellite altimetry; Oceanography; Sea level; Coastal oceanography; Cryospheric sciences; Hydrology.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/79999/82978.pdf

Scattering of inertial waves by an ocean front - Comments
Provedor de dados: 5
Autores: Klein, Patrice; Treguier, Anne-marie.
Rubenstein and Roberts (1986, hereafter RR86) have studied the scattering of inertial waves by a geostrophic jet. The most remarkable effect of the jet is to concentrate near-inertial energy in the negative vorticity region. This effect is due to the horizontal dispersion of near-inértial waves. It is demonstrated by RR86 Using a stratified linearized model. A similar result has been obtaîned by Kunze (1985) using a ray-tracing approach and bas been confirmed by observations (Kunze and Stanford 1984). Another result of RR86 concems the mixed layer depth variations. Their Figs. 3 and 8 show a systematic downwelling in the negative vorticity region of the jet and systematic upwelling in the positive vorticity region. Although large upwellings and...
Tipo: Text
Ano: 1995
URL: http://archimer.ifremer.fr/doc/00254/36565/35119.pdf

High‐frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean
Provedor de dados: 5
Autores: 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 (&lt; 50 km) and frequencies larger than one day‐1, including internal gravity waves, has never been explicitly...
Tipo: Text
Palavras-chave: Ocean heat transport&lt; /AUTHOR_KEYWORD&gt; High frequency&lt; /AUTHOR_KEYWORD&gt; Ocean front&lt; /AUTHOR_KEYWORD&gt; Eddies&lt; /AUTHOR_KEYWORD&gt; Eddy transport&lt; /AUTHOR_KEYWORD&gt.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00643/75508/76354.pdf

Cyclone-Anticyclone Asymmetry in Geophysical Turbulence
Provedor de dados: 5
Autores: Roullet, Guillaume; Klein, Patrice.
We address the problem of cyclone-anticyclone asymmetry in geophysical turbulence using a direct numerical simulation with high Reynolds number Re similar to 15 000 that includes an active upper boundary and interior dynamics. The regime, characterized by a finite Rossby number (Ro similar to 0.6) strongly departs from the classical quasigeostrophic regime. The numerical resolution is pushed to the limit of today's supercomputer capabilities ensuring more than two decades free of viscous effects. The results show a strong cyclonic dominance in the upper layers that is stronger for filaments than for vortices. This is in contrast with similar studies that have no active upper boundary which reported either anticyclone dominance or a symmetry between...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00005/11587/8240.pdf

Enhanced upward heat transport at deep submesoscale ocean fronts
Provedor de dados: 5
Autores: Siegelman, Lia; Klein, Patrice; Rivière, Pascal; Thompson, Andrew F.; Torres, Hector S.; Flexas, Mar; Menemenlis, Dimitris.
The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from metres to thousands of kilometres. In the classical paradigm, fine oceanic scales, less than 20 km in size, are thought to drive a significant downward heat transport from the surface to the ocean interior, which increases oceanic heat uptake. Here we use a combination of satellite and in situ observations in the Antarctic Circumpolar Current to diagnose oceanic vertical heat transport. The results explicitly demonstrate how deep-reaching submesoscale fronts, with a size smaller than 20 km, are generated by mesoscale eddies of size 50–300 km. In contrast to the classical...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00594/70562/71323.pdf

Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean
Provedor de dados: 5
Autores: Sasaki, Hideharu; Klein, Patrice; Sasai, Yoshikazu; Qiu, Bo.
The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one, with a 1/10° horizontal grid spacing, 54 vertical levels, represents dynamics of physical scales larger than 50 km. The second one, with a 1/30° grid spacing, 100 vertical levels, takes into account the dynamics of physical scales down to 16 km. Comparison clearly emphasizes in the whole North Pacific Ocean, not only a significant KE increase by a factor up to three, but also the emergence of seasonal variability when the scale range 16–50 km (called submesoscales in this study) is...
Tipo: Text
Palavras-chave: Submesoscale turbulence; Scale interactions; Mixed-layer instability; High-resolution simulations; North Pacific.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00392/50347/51110.pdf

Dissipation of the energy imparted by mid-latitude storms in the Southern Ocean
Provedor de dados: 5
Autores: Jouanno, Julien; Capet, Xavier; Madec, Gurvan; Roullet, Guillaume; Klein, Patrice.
The aim of this study is to clarify the role of the Southern Ocean storms on interior mixing and meridional overturning circulation. A periodic and idealized numerical model has been designed to represent the key physical processes of a zonal portion of the Southern Ocean located between 70 and 40° S. It incorporates physical ingredients deemed essential for Southern Ocean functioning: rough topography, seasonally varying air–sea fluxes, and high-latitude storms with analytical form. The forcing strategy ensures that the time mean wind stress is the same between the different simulations, so the effect of the storms on the mean wind stress and resulting impacts on the Southern Ocean dynamics are not considered in this study. Level and distribution of...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00343/45404/44919.pdf

Dynamic Interpolation of Sea Surface Height and Potential Applications for Future High-Resolution Altimetry Mapping
Provedor de dados: 5
Autores: Ubelmann, Clement; Klein, Patrice; Fu, Lee-lueng.
Many issues may challenge standard interpolation techniques to produce high-resolution gridded maps of sea surface height in the context of future missions like Surface Water and Ocean Topography (SWOT). The present study proposes a new method to address these challenges. Based on the conservation of potential vorticity, the method provides a simple dynamic approach to interpolation through temporal gaps between high spatial resolution observations. For gaps shorter than 20 days, the dynamic interpolation is extremely efficient and allows for the reconstruction of the time evolution of small mesoscale eddies (below 100 km) that would be smoothed out by conventional methods based on optimal mapping. Such a simple approach offers some perspectives for...
Tipo: Text
Palavras-chave: : Conservation equations; Eddies; Mesoscale processes; Mesoscale forecasting; Interpolation schemes; Quasigeostrophic models.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00252/36313/34865.pdf

Do altimeter wavenumber spectra agree with the interior or surface quasigeostrophic theory?
Provedor de dados: 5
Autores: Le Traon, Pierre-yves; Klein, Patrice; Hua, Bach-lien; Dibarboure, G.
In high-eddy-energy regions, it is generally assumed that sea level wavenumber spectra compare well with quasigeostrophic (QG) turbulence models and that spectral slopes are close to the expected k(-5) law. This issue is revisited here. Sea level wavenumber spectra in the Gulf Stream, Kuroshio, and Agulhas regions are estimated using the most recent altimeter datasets [the Ocean Topography Experiment (TOPEX)/ Poseidon, Jason-1, the Environmental Satellite (Envisat), and the Geosat Follow-On]. The authors show that spectral slopes in the mesoscale band are significantly different from a k(-5) law, in disagreement with the QG turbulence theory. However, they very closely follow a k(-11/3) slope, which indicates that the surface quasigeostrophic theory (SQG)...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4118.pdf

Reconstructability of 3-Dimensional Upper Ocean Circulation from SWOT Sea Surface Height Measurements
Provedor de dados: 5
Autores: Qiu, Bo; Chen, Shuiming; Klein, Patrice; Ubelmann, Clement; Fu, Lee-lueng; Sasaki, Hideharu.
Utilizing the framework of effective surface quasi-geostrophic (eSQG) theory, we explored the potential of reconstructing the 3D upper ocean circulation structures, including the balanced vertical velocity (w) field, from high-resolution sea surface height (SSH) data of the planned SWOT satellite mission. Specifically, we utilized the 1/30°, submesoscale-resolving, OFES model output and subjected it through the SWOT simulator that generates the along-swath SSH data with expected measurement errors. Focusing on the Kuroshio Extension region in the North Pacific where regional Rossby numbers range from 0.22 to 0.32, we found that the eSQG dynamics constitutes an effective framework for reconstructing the 3D upper ocean circulation field. Using the modeled...
Tipo: Text
Palavras-chave: Variability; Models and modeling; General circulation models; Vertical motion; Circulation/ Dynamics; Quasigeostrophic models; Mesoscale processes; Observational techniques and algorithms; Oceanic variability; Altimetry.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00309/42032/41331.pdf

A numerical study of turbulent processes in the marine upper layers
Provedor de dados: 5
Autores: Klein, Patrice; Coantic, Michel.
A second-order turbulence closure model, similar to Mellor and Yamada's (1974) level-3 model, is implemented. This is used to investigate the role of the different turbulent processes and the resulting dynamical and thermal structures, for oceanic upper layers subjected to a variety of unsteady atmospheric forcings. From the distributions obtained for current and temperature, turbulence levels, the production, transfer and dissipation terms in the turbulent kinetic energy and temperature variance budgets, the physics of the oceanic mixed layer and thermocline can be discussed and comparisons made with the models of Mellor and Durbin (1975), Warn-Varnas and Piacsek (1979) and Kundu (1980) and some experimental data. Most often, shear production and viscous...
Tipo: Text
Ano: 1981
URL: http://archimer.ifremer.fr/doc/00254/36569/35122.pdf

Impact of Small-Scale Structures on Two Energetic Dynamical Oceanic Regimes
Provedor de dados: 5
Autores: Klein, Patrice; Hua, Bach-lien; Le Gentil, Sylvie; Sasaki, Hideharu.
The big challenge of the next decade for the oceanic sciences is to adopt a multi-scale approach because of the strong nonlinearity of the oceanic fluid. This can be undertaken only through numerical simulations with ultra-high resolution. Within this context, the purpose of our projects is to fully explore two energetic dynamical oceanic regimes that have a major impact on the general oceanic circulation: the mesoscale eddy regime at mid-latitudes and the equatorial regime. Expected results will help for the configuration of realistic numerical simulations to be performed in 2006 by the OFES group on the Earth Simulator and they should benefit to future climate models. These studies make use of the Primitive Equations model ROMS (Regional Ocean Modelling...
Tipo: Text
Palavras-chave: Mesoscale oceanic eddies; Equatorial dynamics.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/00067/17783/15306.pdf

Instability of wind-forced inertial oscillations
Provedor de dados: 5
Autores: Treguier, Anne-marie; Klein, Patrice.
An instability mechanism that can amplify wind-forced inertial oscillations in the upper ocean is investigated. This forced instability happens because of the phase relationship between the mixed-layer depth and the surface current. It allows the inertial oscillations propagating against the wind to extract energy from it and amplify. The key ingredients for the instability to work are (a) a non-zero mean wind stress, (b) a spatial variability of the oscillations in the direction of the wind stress. The amplification is demonstrated using a simple shallow-water model in a few situations: the dispersion of a localized disturbance with steady and time-varying wind forcing, generation of inertial waves at a coast, and spatial variability induced by mesoscale...
Tipo: Text
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00196/30687/30398.pdf

Satellite Altimetry and Key Observations: What We've Learned, and What's Possible with New Technologies
Provedor de dados: 5
Autores: Scott, Robert B.; Bourassa, Mark; Chelton, Dudley; Cipollini, Paolo; Ferrari, Raffaele; Fu, Lee-lueng; Galperin, Boris; Gille, Sarah; Huang, Huei-ping; Klein, Patrice; Maximenko, Nikolai; Morrow, Rosemary; Qiu, Bo; Rodriguez, Ernesto; Stammer, Detlef; Tailleux, Remi; Wunsch, Carl.
The advent of high accuracy satellite altimetry in the 1990's brought the first global view of ocean dynamics, which together with a global network of supporting observations brought a revolution in understanding of how the ocean works [1]. At present a constellation of flying satellite missions routinely provides sea level anomaly, sea winds, sea surface temperature (SST), ocean colour, etc. with mesoscale resolution (50km to 100km, 20 to 150 days) on a near global scale. Concurrently, in situ monitoring is carried out by surface drifters, Argo floats, moorings, sea gliders as well as ship-borne CTD (Conductivity-Temperature-Depth) and XBT (Expendable Bathythermograph) (to measure profiles of temperature and salinity), and ADCP (Acoustic Doppler Current...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00067/17791/15315.pdf

The influence of geostrophic strain on oceanic ageostrophic motion and surface chlorophyll
Provedor de dados: 5
Autores: Zhang, Zhengguang; Qiu, Bo; Klein, Patrice; Travis, Seth.
Oceanic submesoscale ageostrophic processes have been progressively recognized as an important upwelling mechanism to close the nutrient budget and sustain the observed primary production of phytoplankton in the euphotic layer. Their relatively small spatio-temporal scales (of 1~10 km and a few days) have hindered a systematic observational quantification of the submesoscale ageostrophic flow variability and its impact on ocean biogeochemistry. By combining surface drifters, satellite altimetry and satellite ocean-color data, we detect that when the strain rate of mesoscale surface geostrophic flow is strong, it favors a higher ageostrophic kinetic energy level and an increase in surface chlorophyll concentration. The strain-induced frontal processes are...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62057/66227.pdf

Submesoscale ocean fronts act as biological hotspot for southern elephant seal
Provedor de dados: 5
Autores: Siegelman, Lia; O’toole, Malcolm; Flexas, Mar; Rivière, Pascal; Klein, Patrice.
The area west of the Kerguelen Islands (20–70°E/45–60°S) is characterized by a weak mesoscale activity except for a standing meander region of the Antarctic Circumpolar Current (ACC) localized between 20 and 40°E. A unique bio-physical dataset at high-resolution collected by a southern elephant seal (Mirounga leonina) reveals a conspicuous increase in foraging activity at the standing meander site up to 5 times larger than during the rest of her three-month trip west of the Kerguelen Islands. Here, we propose a physical explanation for such high biological activity based on the study of small-scale fronts with scales of 5 to 20 km, also called submesoscales. The standing meander is associated with intensified frontal dynamics at submesoscale, not observed...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00489/60038/63305.pdf

Ocean Scale Interactions from Space
Provedor de dados: 5
Autores: Klein, Patrice; Lapeyre, Guillaume; Siegelman, Lia; Qiu, Bo; Fu, Lee‐lueng; Torres, Hector; Su, Zhan; Menemenlis, Dimitris; Le Gentil, Sylvie.
Satellite observations of the last two decades have led to a major breakthrough emphasizing the existence of a strongly energetic mesoscale turbulent eddy field in all the oceans. This ocean mesoscale turbulence (OMT) is characterized by cyclonic and anticyclonic eddies (with a 100‐‐300 km size and depth scales of ~500‐‐1000 m) that capture approximatively 80% of the total kinetic energy and is now known to significantly impact the large‐scale ocean circulation, the ocean's carbon storage, the air‐sea interactions and therefore the Earth climate as a whole. However, OMT revealed by satellite observations has properties that differ from those related to classical geostrophic turbulence theories. In the last decade, a large number of theoretical and...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00488/59951/63202.pdf

Global estimates of the energy transfer from the wind to the ocean, with emphasis on near‐inertial oscillations
Provedor de dados: 5
Autores: Flexas, M. Mar; Thompson, Andrew F.; Torres, Hector S.; Klein, Patrice; Farrar, J. Thomas; Zhang, Hong; Menemenlis, Dimitris.
Estimates of the kinetic energy transfer from the wind to the ocean are often limited by the spatial and temporal resolution of surface currents and surface winds. Here, we examine the wind work in a pair of global, very high‐resolution (1/48° and 1/24° ), MITgcm simulations in Latitude‐Longitude‐Cap configuration (LLC) that provide hourly output at spatial resolutions of a few kilometers and include tidal forcing. A cospectrum analysis of wind stress and ocean surface currents shows positive contribution at large scales (&gt;300 km) and near‐inertial frequency, and negative contribution from mesoscales, tidal frequencies and internal gravity waves (IGWs). Larger surface kinetic energy fluxes are in the Kuroshio in winter at large scales (40 mW m−2) and...
Tipo: Text
Palavras-chave: Surface fluxes; Inertial oscillations; Wind power; Kinetic energy budget; Global ocean model; MITgcm.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62058/66232.pdf

Pathways of ocean heat towards Pine Island and Thwaites grounding lines
Provedor de dados: 5
Autores: Nakayama, Yoshihiro; Manucharyan, Georgy; Zhang, Hong; Dutrieux, Pierre; Torres, Hector S.; Klein, Patrice; Seroussi, Helene; Schodlok, Michael; Rignot, Eric; Menemenlis, Dimitris.
In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high ice shelf melting near the ice sheet grounding lines, accelerating ice flow, and controlling the pace of future Antarctic contributions to global sea level. The pathways of mCDW towards grounding lines are crucial as they directly control the heat reaching the ice. A realistic representation of mCDW circulation, however, remains challenging due to the sparsity of in-situ observations and the difficulty of ocean models to reproduce the available observations. In this study, we use an unprecedentedly high-resolution (200 m horizontal and 10 m vertical grid spacing) ocean model that resolves shelf-sea and sub-ice-shelf environments in qualitative...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00593/70560/68742.pdf

Diagnosis of vertical velocities in the upper ocean from high resolution sea surface height
Provedor de dados: 5
Autores: Klein, Patrice; Isern-fontanet, Jordi; Lapeyre, Guillaume; Roullet, G.; Danioux, Eric; Chapron, Bertrand; Le Gentil, Sylvie; Sasaki, H.
A surface Quasi-Geostrophy based (eSQG) method to diagnose the vertical velocity field from Sea Surface Height (SSH) is assessed using high resolution simulations. These simulations concern a turbulent eddy field with large Rossby numbers and energetic wind-driven motions. Results indicate that low-frequency vertical velocities (and also horizontal motions) can be reconstructed within a range of scales between 20 km and 400 km from the surface down to 500 m. The only information needed is a single high-resolution SSH snapshot and information on the large-scale vertical stratification. Inertial motions are naturally filtered because they do not contaminate SSH as we demonstrate. These results are encouraging and further strengthen previous studies using the...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00000/11094/7418.pdf

Surface kinetic energy transfer in surface quasi-geostrophic flows
Provedor de dados: 5
Autores: Capet, Xavier; Klein, Patrice; Hua, Bach-lien; Lapeyre, Guillaume; Mcwilliams, James C.
The relevance of surface quasi-geostrophic dynamics (SQG) to the upper ocean and the atmospheric tropopause has been recently demonstrated in a wide range of conditions. Within this context, the properties of SQG in terms of kinetic energy (KE) transfers at the surface are revisited and further explored. Two well-known and important properties of SQG characterize the surface dynamics: (i) the identity between surface velocity and density spectra (when appropriately scaled) and (ii) the existence of a forward cascade for surface density variance. Here we show numerically and analytically that (i) and (ii) do not imply a forward cascade of surface KE (through the advection term in the KE budget). On the contrary, advection by the geostrophic flow primarily...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4623.pdf

Destabilization of mixed Rossby gravity waves and the formation of equatorial zonal jets
Provedor de dados: 5
Autores: Hua, Bach-lien; D'Orgeville, Marc; Fruman, Mark; Menesguen, Claire; Schopp, Richard; Klein, Patrice; Sasaki, H.
stability of mixed Rossby gravity (MRG) waves has been investigated numerically using three-dimensionally consistent high-resolution Simulations of the continuously stratified primitive equations. For short enough zonal wavelength, the westward phase propagating MRG wave is strongly destabilized by barotropic shear instability leading , to the formation of zonal jets. The large-scale instability of the zonally short wave,generates zonal jets because it consists primarily of sheared meridional motions, as shown recently for the short barotropic Rossby wave problem.   Simulations were done in a variety of domain geometries: a periodic re-entrant channel, a basin with a short MRG wave forced in its western part and a very long channel initialized with a...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-5913.pdf

Potential use of microwave sea surface temperatures for the estimation of ocean currents - art. no. L24608
Provedor de dados: 5
Autores: Isern-fontanet, Jordi; Chapron, Bertrand; Lapeyre, Guillaume; Klein, Patrice.
In this paper, we examine the emerging potential offered by satellite microwave radiometer SST measurements to complement altimeter data to quantitatively derive surface ocean currents. The proposed methodology does not follow standard sequential temporal analysis but follows the application of the Surface Quasi-Geostrophic (SQG) theory. Accordingly, under favourable environmental conditions, the implementation for this methodology is simple and robust, and most importantly, solely requires a single SST image. For the present demonstration, altimetric measurements are used to infer a necessary adjustment to match the kinetic energy level for length scales smaller than 300 km. This helps to derive a regional effective Brunt-Vaisala frequency to produce SQG...
Tipo: Text
Palavras-chave: Microwave radiometers; Sea surface temperature; Surface quasi geostrophy.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2177.pdf

QuasiGeostrophic Diagnosis of Mixed-Layer Dynamics Embedded in a Mesoscale Turbulent Field
Provedor de dados: 5
Autores: Chavanne, Cedric P.; Klein, Patrice.
A quasigeostrophic model is developed to diagnose the three-dimensional circulation, including the vertical velocity, in the upper ocean from high-resolution observations of sea surface height and buoyancy. The formulation for the adiabatic component departs from the classical surface quasigeostrophic framework considered before since it takes into account the stratification within the surface mixed layer that is usually much weaker than that in the ocean interior. To achieve this, the model approximates the ocean with two constant stratification layers: a finite-thickness surface layer (or the mixed layer) and an infinitely deep interior layer. It is shown that the leading-order adiabatic circulation is entirely determined if both the surface...
Tipo: Text
Palavras-chave: Circulation; Dynamics; Ageostrophic circulations; Mesoscale processes; Ocean dynamics; Vertical motion; Models and modeling; Diagnostics; Quasigeostrophic models.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00309/42031/41330.pdf

Interannual to Decadal Variations of Submesoscale Motions around the North Pacific Subtropical Countercurrent
Provedor de dados: 5
Autores: Sasaki, Hideharu; Qiu, Bo; Klein, Patrice; Sasai, Yoshikazu; Nonaka, Masami.
The outputs from a submesoscale permitting hindcast simulation from 1990 to 2016 are used to investigate the interannual to decadal variations of submesoscale motions. The region we focus on is the subtropical Northwestern Pacific including the subtropical countercurrent. The submesoscale kinetic energy (KE) is characterized by strong interannual and decadal variability, displaying larger magnitudes in 1996, 2003, and 2015, and smaller magnitudes in 1999, 2009, 2010, and 2016. These variations are partially explained by those of the available potential energy (APE) release at submesoscale driven by mixed layer instability in winter. Indeed, this APE release depends on the mixed layer depth and horizontal buoyancy gradient, both of them modulated with the...
Tipo: Text
Palavras-chave: Submesoscale motion; Interannual to decadal variations; Mixed layer instability; North Pacific Subtropical Countercurrent.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00641/75287/75641.pdf

Diagnosing Surface Mixed Layer Dynamics from High-Resolution Satellite Observations: Numerical Insights
Provedor de dados: 5
Autores: Ponte, Aurelien; Klein, Patrice; Capet, Xavier; Le Traon, Pierre-yves; Chapron, Bertrand; Lherminier, Pascale.
High-resolution numerical experiments of ocean mesoscale eddy turbulence show that the wind-driven mixed layer (ML) dynamics affects mesoscale motions in the surface layers at scales lower than O(60 km). At these scales, surface horizontal currents are still coherent to, but weaker than, those derived from sea surface height using geostrophy. Vertical motions, on the other hand, are stronger than those diagnosed using the adiabatic quasigeotrophic (QG) framework. An analytical model, based on a scaling analysis and on simple dynamical arguments, provides a physical understanding and leads to a parameterization of these features in terms of vertical mixing. These results are valid when the wind-driven velocity scale is much smaller than that associated with...
Tipo: Text
Palavras-chave: Mesoscale processes; Ocean dynamics; Turbulence.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00170/28076/26291.pdf

Low-mode internal tides and balanced dynamics disentanglement in altimetric observations: Synergy with surface density observations
Provedor de dados: 5
Autores: Ponte, Aurelien; Klein, Patrice; Dunphy, Michael; Le Gentil, Sylvie.
The performance of a tentative method that disentangles the contributions of a low-mode internal tide on sea level from that of the balanced mesoscale eddies is examined using an idealized high resolution numerical simulation. This disentanglement is essential for proper estimation from sea level of the ocean circulation related to balanced motions. The method relies on an independent observation of the sea surface water density whose variations are 1/dominated by the balanced dynamics and 2/correlate with variations of potential vorticity at depth for the chosen regime of surface-intensified turbulence. The surface density therefore leads via potential vorticity inversion to an estimate of the balanced contribution to sea level fluctuations. The...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00374/48487/48761.pdf

The vertical structure of open-ocean submesoscale variability during a full seasonal cycle
Provedor de dados: 5
Autores: Erickson, Zachary K; Thompson, Andrew F; Callies, Jörn; Yu, Xiaolong; Naveira Garabato, Alberto; Klein, Patrice.
Submesoscale dynamics are typically intensified at boundaries and assumed to weaken below the mixed layer in the open ocean. Here, we assess both the seasonality and the vertical distribution of submesoscale motions in an open ocean region of the northeast Atlantic. Second-order structure functions, or variance in properties separated by distance, are calculated from submesoscale-resolving ocean glider and mooring observations, as well as a 1/48° numerical ocean model. This data set combines a temporal coverage that extends through a full seasonal cycle, a horizontal resolution that captures spatial scales as small as 1 km, and vertical sampling that provides near-continuous coverage over the upper 1000 m. While kinetic and potential energies undergo a...
Tipo: Text
Palavras-chave: Instability; Mixing; Small scale processes; Buoy observations; Profilers; Oceanic.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00592/70388/68470.pdf

The Vertical Pump Organized by the Mesoscale Oceanic Eddies
Provedor de dados: 5
Autores: Klein, Patrice; Hua, Bach-lien; Le Gentil, Sylvie; Sasaki, Hideharu.
The purpose of this project is to study the dynamics of the upper oceanic layers (the first 1000m below the surface) and principally to get new insights on the effectiveness of the oceanic vertical pump at a basin scale through numerical experiments using ultra-high resolution. If the magnitude of this vertical pump when using such a resolution is much larger than anticipated, then the expected results should have an important impact on basin-scale SST and circulation through the vertical fluxes of heat and potential vorticity. Indeed preliminary studies already indicate the significant contribution of this eddy vertical pump to the modification of the surface layers heat content ([1], [2]). Thus the expected new results should be of importance for climate...
Tipo: Text
Palavras-chave: Mesoscale oceanic eddies; Submesoscale dynamics; Vertical pump.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/00067/17782/15304.pdf

Sub‐mesoscale fronts modify elephant seals foraging behavior
Provedor de dados: 5
Autores: Rivière, Pascal; Jaud, Thomas; Siegelman, Lia; Klein, Patrice; Cotté, Cedric; Le Sommer, Julien; Dencausse, Guillaume; Guinet, Christophe.
Sub‐mesoscale fronts—with scales from 1 to 50 km are ubiquitous in satellite images of the world oceans. They are known to generate strong vertical velocities with significant impacts on biogeochemical fluxes and pelagic ecosystems. Here, we use a unique data set, combining high‐resolution behavioral and physical measurements, to determine the effects of sub‐mesoscale structures on the foraging behavior of 12 instrumented female southern elephant seals. These marine mammals make long voyages (several months over more than 2000 km), diving and feeding continuously in the Antarctic Circumpolar Current. Our results show that elephant seals change their foraging behavior when crossing sub‐mesoscale fronts: They forage more and at shallower depths inside...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00584/69636/67497.pdf

A Deep Learning approach to spatiotemporal SSH interpolation and estimation of deep currents in geostrophic ocean turbulence
Provedor de dados: 5
Autores: Manucharyan , Georgy E.; Siegelman , Lia; Klein, Patrice.
Satellite altimeters provide global observations of sea surface height (SSH) and present a unique dataset for advancing our theoretical understanding of upper ocean dynamics and monitoring its variability. Considering that mesoscale SSH patterns can evolve on timescales comparable to or shorter than satellite return periods, it is challenging to accurately reconstruct the continuous SSH evolution as currently available altimetry observations are still spatially and temporally sparse. Here we explore the possibility of SSH interpolation via Deep Learning by using synthetic observations from an idealized quasigeostrophic (QG) model of baroclinic ocean turbulence. We demonstrate that Convolutional Neural Networks with Residual Learning are superior in SSH...
Tipo: Text
Palavras-chave: Baroclinic instability; Deep Learning; Deep ocean flows; Mesoscale eddies; Sea surface height interpolation; State estimation.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00663/77502/79235.pdf

Impact of oceanic-scale interactions on the seasonal modulation of ocean dynamics by the atmosphere
Provedor de dados: 5
Autores: Sasaki, Hideharu; Klein, Patrice; Qiu, Bo; Sasai, Yoshikazu.
Ocean eddies (with a size of 100-300 km), ubiquitous in satellite observations, are known to represent about 80% of the total ocean kinetic energy. Recent studies have pointed out the unexpected role of smaller oceanic structures (with 1-50 km scales) in generating and sustaining these eddies. The interpretation proposed so far invokes the internal instability resulting from the large-scale interaction between upper and interior oceanic layers. Here we show, using a new high-resolution simulation of the realistic North Pacific Ocean, that ocean eddies are instead sustained by a different process that involves small-scale mixed-layer instabilities set up by large-scale atmospheric forcing in winter. This leads to a seasonal evolution of the eddy kinetic...
Tipo: Text
Palavras-chave: Earth sciences; Oceanography.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00250/36098/34642.pdf

Low-mode internal tide propagation in a turbulent eddy field
Provedor de dados: 5
Autores: Dunphy, Michael; Ponte, Aurelien; Klein, Patrice; Le Gentil, Sylvie.
Understanding how internal tides distort and lose coherence as they propagate through the ocean has been identified as a key issue for interpreting data from the upcoming wide-swath altimeter mission SWOT. This study addresses that issue through the analysis of numerical experiments where a low mode internal tide propagates through a quasi-geostrophic turbulent jet. We present a set of reduced equations based on vertical mode projections that describe the dynamics of the low-mode internal tides as they propagate through the slower turbulent field. Diagnostics of the terms responsible for the interaction between the wave and the slow circulation are computed from the numerical outputs. The large scale change of stratification, on top of eddies and jet...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00342/45364/44853.pdf

New production stimulated by high-frequency winds in a turbulent mesoscale eddy field
Provedor de dados: 5
Autores: Levy, M.; Klein, Patrice; Ben Jelloul, M.
Using an idealized model of an oligotrophic open-ocean region characterized by intense sub-mesoscale turbulence, we show that the presence of energetic near-inertial motions, forced by high-frequency winds, triggers transient nutrient inputs in the surface mixed-layer, stimulating new production. We also show that this production increase is larger than the increase due to the Ekman transport resulting from a slow-evolving wind forcing. The nutrient supplies are due to the interaction between near-inertial motions and the submesoscale frontogenetic dynamics that reinforces both the vertical advection and vertical diffusion, especially within sub-mesoscales features. The net result is an uplift of new production from the subsurface to the mixed-layer. A...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6767.pdf

Ocean submesoscales as a key component of the global heat budget
Provedor de dados: 5
Autores: Su, Zhan; Wang, Jinbo; Klein, Patrice; Thompson, Andrew F.; Menemenlis, Dimitris.
Recent studies highlight that oceanic motions associated with horizontal scales smaller than 50 km, defined here as submesoscales, lead to anomalous vertical heat fluxes from colder to warmer waters. This unique transport property is not captured in climate models that have insufficient resolution to simulate these submesoscale dynamics. Here, we use an ocean model with an unprecedented resolution that, for the first time, globally resolves submesoscale heat transport. Upper-ocean submesoscale turbulence produces a systematicallyupward heat transport that is five times larger than mesoscale heat transport, with wintertime averages up to 100 W/m2 for mid-latitudes. Compared to a lower-resolution model, submesoscale heat transport warms the sea surface up to...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00449/56019/57535.pdf

Available potential energy diagnosis in a direct numerical simulation of rotating stratified turbulence
Provedor de dados: 5
Autores: Roullet, Guillaume; Klein, Patrice.
Review of three studies devoted to the available potential energy (APE) leads to the proposal of a diagnosis for APE, well-suited for rotating stratified flows within the primitive equations (PE) framework in which anharmonic effects (due to large vertical displacements of isopycnals) are permitted. The chosen diagnosis is based on the APE definition of Holliday &amp; McIntyre (J. Fluid Mech., vol. 107, 1981, pp. 221-225) and uses the background stratification of Winters et al. (J. Fluid Mech., vol. 289, 1995, pp. 115-128). Subsequent evaluation of the APE in a PE direct simulation (1/100 degrees, 200 levels) of oceanic mesoscale turbulence indicates that anharmonic effects are significant. These effects are due to large vertical displacements of the...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6391.pdf

An index to distinguish surface and subsurface intensified vortices from surface observations
Provedor de dados: 5
Autores: Assassi, Charefeddine; Morel, Y.; Vandermeirsch, Frederic; Chaigneau, A.; Pegliasco, C.; Morrow, R.; Colas, F.; Fleury, S.; Carton, Xavier; Klein, Patrice; Cambra, R.
In this study, we first show that it is difficult to reconstruct the vertical structure of vortices using only surface observations. In particular we show that the recent SQG and ISQG methods systematically lead to surface intensified vortices and those subsurface intensified vortices are thus not correctly modelled.  We then investigate the possibility to distinguish between surface and subsurface intensified eddies from surface data only, using the sea surface height and the sea surface temperature available from satellite observations. A simple index, based on the ratio of the sea surface temperature anomaly and the sea level anomaly, is proposed. While the index is expected to give perfect results for isolated vortices, we show that in a complex...
Tipo: Text
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00343/45406/44921.pdf

Reconstructing Upper Ocean Vertical Velocity Field from Sea Surface Height in the Presence of Unbalanced Motion
Provedor de dados: 5
Autores: Qiu, Bo; Chen, Shuiming; Klein, Patrice; Torres, Hector; Wang, Jinbo; Fu, Lee-lueng; Menemenlis, Dimitris.
Reconstructability of upper ocean vertical velocity (w) and vorticity (ζ) fields from high-resolution sea surface height (SSH) data is explored using the global 1/48° horizontal-resolution MITgcm output in the context of the forth-coming Surface Water and Ocean Topography (SWOT) mission. By decomposing w with an omega equation of the primitive-equation system and by taking into account the measurement design of the SWOT mission, this study seeks to reconstruct the subinertial, balanced w and ζ signals. By adopting the effective surface quasi-geostrophic (eSQG) framework and applying to the Kuroshio Extension region of the North Pacific, we find that the target and reconstructed fields have a spatial correlation of ~0.7 below the mixed layer for w and 0.7 ~...
Tipo: Text
Palavras-chave: Eddies; Mesoscale processes; Ocean dynamics; Vertical motion; Altimetry.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00593/70561/68744.pdf

A numerical study of baroclinic instability at large supercriticality
Provedor de dados: 5
Autores: Klein, Patrice; Pedlosky, J.
A series of numerical integrations of the two-layer quasi-geostrophic model were carried out to investigate the nonlinear dynamics of baroclinically unstable waves at supercriticalities of O(1). The results extend and are contrasted with the results of weakly nonlinear theory valid only for small supercriticality. Particular attention is paid to that sector of parameter space in which the transition from regular to aperiodic behavior is observed for weakly nonlinear waves. It is found that aperiodic, chaotic behavior extends to parameter domains of higher dissipation as a consequence of finite amplitude effects as the supercriticality increases. Sensitive dependence on parameters remains a hallmark of the system as intervals of chaotic, periodic and steady...
Tipo: Text
Ano: 1986
URL: http://archimer.ifremer.fr/doc/00254/36567/35120.pdf

Can oceanic submesoscale processes be observed with satellite altimetry?
Provedor de dados: 5
Autores: Chavanne, Cedric; Klein, Patrice.
High-resolution (2 km and hourly) observations of surface currents from High-Frequency Radars are analyzed in terms of sea level anomalies (SLA) and compared with data from two satellite altimeter ground tracks. Purpose is to investigate whether ocean submesoscale processes can be observed with satellite altimetry. Our results highlight two major problems that must be overcome before being able to resolve submesoscale processes with altimetry: (i) signal contamination from high-frequency motions and in particular from incoherent internal tides (near-inertial oscillations have no effect on SLA), and (ii) measurement noise which prevents the computation of accurate cross-track currents on scales O (10 km). The latter may be overcome by future satellite...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00019/13037/10153.pdf

Seasonality in Transition Scale from Balanced to Unbalanced Motions in the World Ocean
Provedor de dados: 5
Autores: Qiu, Bo; Chen, Shuiming; Klein, Patrice; Wang, Jinbo; Torres, Hector; Fu, Lee-lueng; Menemenlis, Dimitris.
The transition scale Lt from balanced geostrophic motions to unbalanced wave motions, including near-inertial flows, internal tides and inertia-gravity wave continuum, is explored using the output from a global 1/48° horizontal resolution MITgcm simulation. Defined as the wavelength with equal balanced and unbalanced motion kinetic energy (KE) spectral density, Lt is detected to be geographically highly inhomogeneous: it falls below 40 km in the western boundary current and Antarctic Circumpolar Current regions, increases to 40- 100 km in the interior subtropical and subpolar gyres, and exceeds, in general, 200 km in the tropical oceans. With the exception of the Pacific and Indian sectors of the Southern Ocean, the seasonal KE uctuations of the surface...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00423/53431/54318.pdf

Impact of small-scale structures on two energetic dynamical regimes
Provedor de dados: 5
Autores: Klein, Patrice; Hua, Bach-lien; Le Gentil, Sylvie; Roullet, Guillaume; Fruman, Mark; Menesguen, Claire; Sasaki, Hideharu.
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00067/17785/15308.pdf

Diagnosing ocean‐wave‐turbulence interactions from space
Provedor de dados: 5
Autores: Torres, H.s.; Klein, Patrice; Siegelman, L.; Qiu, B.; Chen, S.; Ubelman, C.; Wang, J.; Menemenlis, D.; Fu, L.‐l.
Numerical studies indicate that interactions between ocean internal gravity waves (especially those &lt;100 km) and geostrophic (or balanced) motions associated with mesoscale eddy turbulence (involving eddies of 100–300 km) impact the ocean's kinetic energy budget and therefore its circulation. Results from these studies have never been confirmed by observations in regional or basin‐scale domains. Here we show that internal gravity waves have a spectral signature on sea‐surface height (SSH) during summer that significantly differs from that of balanced motions. These spectral differences lead us to propose a new dynamical framework that quantifies the interactions between internal gravity waves and balanced motions in physical space from SSH snapshots,...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62035/66167.pdf

Intensification of upper ocean submesoscale turbulence through Charney baroclinic instability
Provedor de dados: 5
Autores: Capet, Xavier; Roullet, Guillaume; Klein, Patrice; Maze, Guillaume.
This study focuses on the description of an oceanic variant of the Charney baroclinic instability, arising from the joint presence of i) an equatorward buoyancy gradient that extends from the surface into the ocean interior and ii) reduced subsurface stratification, e.g., as produced by wintertime convection or subduction. We analyze forced-dissipative simulations with and without Charney baroclinic instability (C-BCI). In the former C-BCI strengthens near-surface frontal activity with important consequences in terms of turbulent statistics: increased variance of vertical vorticity and velocity, increased vertical turbulent fluxes. Energetic consequences are explored. Despite the atypical enhancement of submesoscale activity in the simulation subjected to...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00347/45785/45429.pdf

A near-inertial mode observed within a Gulf Stream warm-core ring
Provedor de dados: 5
Autores: Joyce, Terrence M.; Toole, John M.; Klein, Patrice; Thomas, Leif N.
Layering of ocean velocity fine structure has been coherently observed across the entire extent of a Gulf Stream warm-core ring using a shipboard acoustic Doppler current profiler system in September 2009 and independently sampled as the ring transited a moored array. Lines of constant velocity phase generally followed isopycnals as they deepened within the ring center. We also observed a clear separation of the vertical structure of the flows associated with the ring (of order 0.5m/s) with the shorter (200m) and less energetic (similar to 0.2m/s) flows of the velocity fine structure, which was further observed to rotate clockwise with increasing depth, consistent with downward propagating near-inertial waves (NIWs). Observations are consistent with a...
Tipo: Text
Palavras-chave: Near-inertial waves; Warm-core ring; Velocity fine structure.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00148/25929/23966.pdf