A5046068891- Oceanographic and Atmospheric Processes
- Climate variability and models
- Geology and Paleoclimatology Research
- Marine and coastal ecosystems
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Methane Hydrates and Related Phenomena
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Ocean Waves and Remote Sensing
- Reservoir Engineering and Simulation Methods
- Geological Studies and Exploration
- Arctic and Antarctic ice dynamics
- Geological formations and processes
- Aquatic and Environmental Studies
- Marine and fisheries research
- Atmospheric and Environmental Gas Dynamics
- Fluid Dynamics and Turbulent Flows
- Advanced Thermodynamics and Statistical Mechanics
- Hydrocarbon exploration and reservoir analysis
- Solar and Space Plasma Dynamics
- Nonlinear Dynamics and Pattern Formation
- Air Quality Monitoring and Forecasting
- Solidification and crystal growth phenomena
- Ocean Acidification Effects and Responses
University of California, San Diego
2016-2025
Scripps Institution of Oceanography
2015-2024
Woods Hole Oceanographic Institution
1987-2021
University of Bergen
2021
The University of Western Australia
2021
University of Oslo
2021
University of Victoria
2021
Council of Science Editors
2020
Universidad Católica Santo Domingo
2013-2017
CMCC Foundation - Euro-Mediterranean Center on Climate Change
2013
The Ocean State Report is an annual publication of the Copernicus Marine Service that provides a comprehensive and state-of-the-art report on current state, natural variations, ongoing changes in global ocean European regional seas.It meant to act as reference Union for scientific community, international national bodies, general public.Using satellite data, models reanalyses, situ measurements, 4-dimensional view (latitude, longitude, depth, time) blue (e.g.hydrography currents), white...
Abstract The adiabatic pole-to-pole cell of the residual overturning circulation (ROC) is studied in a two-hemisphere, semienclosed basin, with zonally reentrant channel occupying southernmost eighth domain. Three different models increasing complexity are used: simple, analytically tractable averaged model; coarse-resolution numerical model parameterized eddies; and an eddy-resolving general model. Two elements found to be necessary for existence cell: 1) thermally indirect, wind-driven...
Abstract Revolutionary observational arrays, together with a new generation of ocean and climate models, have provided intriguing insights into the Atlantic Meridional Overturning Circulation (AMOC) over last two decades. Theoretical models also changed our view AMOC, providing dynamical framework for understanding observations results complex models. In this paper we review recent advances in conceptual processes maintaining AMOC. We discuss theoretical that address issues such as interplay...
Abstract The processes that determine the depth of Southern Ocean thermocline are considered. In existing conceptual frameworks, is determined by competition between mean and eddy heat transport, with a contribution from interaction stratification in enclosed portion ocean. Using numerical simulations, this study examines equilibration an idealized circumpolar current without topography. authors find eddies much more efficient when topography present, leading to shallower than flat case. A...
Abstract The time-mean zonal and meridional overturning circulations of the entire Mediterranean Sea are studied in both Eulerian residual frameworks. is characterized by cells vertical either or planes with clockwise upper water column counterclockwise deep abyssal regions. composed an cell top 600 m related to classical Wüst two additional cells, one corresponding outflow dense Aegean during Eastern Transient (EMT) other associated formation Rhodes Gyre. variability before, during, after...
While the Atlantic Ocean is ventilated by high-latitude deep water formation and exhibits a pole-to-pole overturning circulation, Pacific does not. This asymmetric global pattern has persisted for past 2–3 million years, with evidence different ventilation modes in deeper past. In current climate, Atlantic-Pacific asymmetry occurs because more saline, enabling convection. To what extent salinity contrast between two basins dominated atmospheric processes (larger net evaporation over...
A modified Stommel two-box model is considered as a minimal representation of the buoyancy-driven ocean circulation. In limit fast temperature relaxation only salinity evolves in time while clamped to prescribed ambient value. The box has no intrinsic variability: just two linearly stable and one unstable equilibria. finite perturbation needed shift system from equilibrium other. minimum amplitude duration are calculated. stochastic component freshwater flux forcing then added effect changes...
Abstract The processes maintaining stratification in the oceanic middepth (between approximately 1000 and 3000 m) are explored using an eddy-resolving general circulation model composed of a two-hemisphere, semienclosed basin with zonal reentrant channel southernmost eighth domain. region lies below wind-driven main thermocline but above diffusively driven abyssal ocean. Here, it is argued that determined primarily model’s Antarctic Circumpolar Current. Competition between mean eddy...
The classical Munk problem of barotropic flow driven by an antisymmetric wind stress exhibits multiple steady solutions in the range moderate to high forcing and low dissipation. Everywhere parameter space a perfectly solution exists which strength cyclonic gyre is equal opposite that anticyclonic gyre. This kind has been well documented literature. In subset pair nonsymmetric stationary coexists with solution. For one member amplitude circulation exceeds flow. other obtained from...
This Oberwolfach workshop was dedicated to continuing the sequence on “Atmosphere-Ocean Science” from (2002, 2006, 2010). The spirit of these events is that an open invitation engage in eye-level exchange recent developments and pressing challenges each participating disciplines, explore possible new routes interdisciplinary cooperation. emphasized “model hierarchies” their importance for systematic development both theoretical understanding methods scientific investigation. To limit its...
The Mediterranean Sea is characterized by an anti-estuarine circulation, with Atlantic Water entering the Strait of Gibraltar at surface and denser waters, formed within basin, exiting depth as Outflow. Early studies identified Western Deep Water, in Gulf Lions, primary source dense water masses contributing to While confirming this finding, more recent analyses in-situ observations have highlighted additional contributions from other intermediate deep masses, such Intermediate Levantine...
Some essential features of a recirculating inertial gyre (the "recirculation") can be analyzed with very simple, analytically tractable model. In wind-driven eddy-resolving general circulation models the recirculation appears as strong sub-basin-scale flow homogeneous potential vorticity. The constant value vorticity decreases increasing forcing/dissipation ratio while size and strength increases. subtropical might driven by anomalous values low carried northward western boundary current. We...
The effect of mesoscale eddies on the vertical heat transport ocean is examined using two eddy‐resolving numerical models. global by mean flow and diffusion are both downwards balanced an upward eddy flux. Mean advective fluxes dominate subpolar regions, while diffusive flux important primarily in subtropics. In subtropical abyss, a combination classical Munk‐type advective‐diffusive balance must be modified. Munk Wunsch (1998) expression for turbulent diffusivity over‐estimates as much...
Abstract A parameterization for eddy buoyancy fluxes use in coarse-grid models is developed and tested against eddy-resolving simulations. The development based on the assumption that eddies are adiabatic (except near surface) observation flux of affected by barotropic, depth-independent eddies. Like previous parameterizations Gent McWilliams (GM) Visbeck et al. (VMHS), horizontal a tracer proportional to local large-scale gradient through transfer coefficient assumed be given product...
Abstract Examination of the energy budget for semienclosed seas with two-layer exchange flow at strait shows that flux open portion boundary (the strait) is proportional to surface buoyancy integrated over basin area, constant proportionality given by interface depth. When positive, negative: these types basins have an estuarine circulation. Antiestuarine a negative flux, which provides positive augmenting wind work in powering The vertically separated flows examined using reanalysis...
Abstract The meridional overturning circulation (MOC) is studied in an idealized domain with two basins connected by a circumpolar channel the southernmost region. Flow forced at surface longitude-independent wind stress, freshwater flux, and fast temperature relaxation to prescribed profiles. only longitudinal asymmetry that one basin twice as wide other. Two states, preferred sinking narrow asymmetrically basin, are compared. In both cases, compensated upwelling everywhere else, including...
The low-frequency linear eigenmodes of the reduced-gravity shallow-water equations with weak friction are calculated numerically and using an analytic approximation. For basins a large variation Coriolis parameter, large-scale emerge: eigenfrequencies integer multiples frequency for gravest mode, which, in turn, has period given by transit time slowest long Rossby wave. e-folding decay times comparable to independent friction. These excited stochastic wind forcing this leads peak spectral...
As a model of the thermohaline circulation ocean we study two-dimensional Boussinesq equations forced by prescribing surface temperature and salinity flux. We simplify motion using an expansion based on small aspect ratio domain. The result is amplitude equation governing evolution depth averaged field. This has multiple, linearly stable equilibria. simplified dynamics Lyapunov functional this variational structure permits simple characterization relative stability alternative steady...
Proxy climate data from the Greenland icecap and marine deposits in Pacific indicate that warm conditions North Atlantic are linked to cool Eastern Equatorial Pacific, vice versa. Our ocean models show surface branch of overturning circulation connecting adjusts by exchanging thermocline water between basins response changes deep formation northern Atlantic. Planetary waves give rise a global oceanic seiche, such volume decreases Pacific‐Indian Ocean while increasing Ocean. We conjecture...
Using velocities from a state estimate, Lagrangian analysis maps the global routes of North Atlantic Deep Water (NADW) exiting and reentering upper branch Meridional Overturning Circulation (AMOC). Virtual particle trajectories followed for 8100 years highlight an route (32%) lower (68%). The latter samples σ2 > 37.07 is further divided into subpolar (20%) abyssal cells (48%). Particles in cell detour Pacific before upwelling Southern Ocean. NADW preferentially upwells north 33°S (67%)....
The spectrum of linear free modes a reduced-gravity ocean in closed basin with weak dissipation is examined. constraint total mass conservation, which the quasigeostrophic formulation determines pressure on boundary as function time, allows existence selected large-scale, low-frequency that are very weakly damped presence dissipation. These can be quasi-resonantly excited by time-dependent forcing near eigenperiods, or during process adjustment to Sverdrup balance steady wind from arbitrary...
A model that isolates the interaction between midlatitude ocean gyres and wind stress due to atmospheric baroclinic eddies is formulated. The atmosphere are coupled through their respective heat balances global momentum conservations enforced. flow creates a steep oceanic thermal front at intergyre boundary. This frontogenesis sharpens temperature gradients locally increases eddy transport. result well-defined storm track that, because of delayed adjustment stress, oscillates in time with...
Abstract The effect of the pole-to-pole surface temperature difference on deep stratification and strength global meridional overturning circulation (MOC) is examined in an eddy-resolving ocean model configured idealized domain roughly representing Atlantic sector. Mesoscale eddies lead to qualitative differences mean MOC compared laminar (i.e., eddy free) models. For example, spreading fluid across model’s representation Antarctic Circumpolar Current (ACC) no longer relies existence a sill...