A5025891516- Oceanographic and Atmospheric Processes
- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Ocean Waves and Remote Sensing
- Meteorological Phenomena and Simulations
- Geology and Paleoclimatology Research
- Fluid Dynamics and Turbulent Flows
- Geomagnetism and Paleomagnetism Studies
- Marine and coastal ecosystems
- Marine and fisheries research
- Reservoir Engineering and Simulation Methods
- Geophysics and Gravity Measurements
- Arctic and Antarctic ice dynamics
- Geological formations and processes
- Theoretical and Computational Physics
- Computational Fluid Dynamics and Aerodynamics
- Fluid Dynamics and Vibration Analysis
- Combustion and flame dynamics
- Nonlinear Dynamics and Pattern Formation
- Fluid Dynamics and Heat Transfer
- Marine and environmental studies
- Methane Hydrates and Related Phenomena
- Laser-Plasma Interactions and Diagnostics
- Geological Studies and Exploration
- Computer Graphics and Visualization Techniques
University of California, Los Angeles
2015-2025
Planetary Science Institute
2004-2024
UCLA Health
2010-2023
University of Washington Applied Physics Laboratory
2019
Tel Aviv University
2019
Laboratory for Ocean Physics and Satellite Remote Sensing
2016
Centre National de la Recherche Scientifique
2016
Institut de Recherche pour le Développement
2016
Université de Bretagne Occidentale
2016
Institut Universitaire Européen de la Mer
2016
Abstract In computational simulations of an idealized subtropical eastern boundary upwelling current system, similar to the California Current, a submesoscale transition occurs in eddy variability as horizontal grid scale is reduced O(1) km. This first paper (in series three) describes terms emergent flow structure and associated time-averaged fluxes. addition mesoscale eddies that arise from primary instability alongshore, wind-driven currents, significant energy transferred into fronts...
Abstract This is the second of three papers investigating regime transition that occurs in numerical simulations for an idealized, equilibrium, subtropical, eastern boundary, upwelling current system similar to California Current. The emergent upper-ocean submesoscale fronts are analyzed from phenomenological and dynamical perspectives, using a combination composite averaging separation distinctive subregions flow. initiating process near-surface frontogenesis. frontal behavior both observed...
Abstract This is the last of a suite three papers about transition that occurs in numerical simulations for an idealized equilibrium, subtropical, eastern-boundary upwelling current system similar to California Current. The mainly explained by emergence ubiquitous submesoscale density fronts and ageostrophic circulations them weakly stratified surface boundary layer. Here high-resolution are further analyzed from perspective kinetic energy (KE) spectrum shape spectral fluxes...
Abstract A set of realistic, very high-resolution simulations is made for the Gulf Stream region using oceanic model Regional Oceanic Modeling System (ROMS) to study life cycle intense submesoscale cold filaments that form on subtropical gyre, interior wall Stream. The surface buoyancy gradients and ageostrophic secondary circulations intensify in response mesoscale strain field as predicted by theory filamentogenesis. It can be understood terms a dual frontogenetic process, along lines...
Abstract In this study, uncoupled and coupled ocean–atmosphere simulations are carried out for the California Upwelling System to assess dynamic interactions, namely, ocean surface current feedback atmosphere. The authors show feedback, by modulating energy transfer from atmosphere ocean, controls oceanic eddy kinetic (EKE). For first time, it is demonstrated that has an effect on stress a counteracting wind itself. acts as killer, reducing half EKE, 27% depth-integrated EKE. On one hand,...
Abstract A detailed view of upper ocean vorticity, divergence, and strain statistics was obtained by a two‐vessel survey in the North Atlantic Mode Water region winter 2012. Synchronous Acoustic Doppler Current Profiler sampling provided first situ estimates full velocity gradient tensor at O(1 km) scale without usual mix spatial temporal aliasing. The observed vorticity distribution mixed layer markedly asymmetric (skewness 2.5), with sparse strands strong cyclonic embedded weak,...
Abstract The California Undercurrent (CUC) flows poleward mostly along the continental slope. It develops a narrow strip of large negative vertical vorticity through turbulent boundary layer and bottom stress. In several downstream locations, current separates, aided by topographic curvature flow inertia, in particular near Point Sur Ridge, south Monterey Bay. When this happens high-vorticity undergoes rapid instability that appears to be mesoscale “eddy-resolving” simulations but is...
Most of the ocean kinetic energy is contained in large scale currents and vigorous geostrophic eddy field, at horizontal scales order 100 km. To achieve equilibrium must viscously dissipate their much smaller scale. However, turbulence characterized by an inverse cascade towards larger scale, pathways toward dissipation are still question. Here, we present a mechanism, context Gulf Stream, where transferred from flow to submesoscale wakes through anticyclonic vertical vorticity generation...
Abstract Under the influences of stable density stratification and earth’s rotation, large-scale flows in ocean atmosphere have a mainly balanced dynamics—sometimes called slow manifold—in sense that there are diagnostic hydrostatic gradient-wind momentum balances constrain fluid acceleration. The nonlinear balance equations widely successful, approximate model for this regime, mathematically explicit limits their time integrability been identified. It is hypothesized these indicative, at...
The oceanic general circulation is forced at large scales and unstable to mesoscale eddies. Large-scale currents eddy flows are approximately in geostrophic balance. Geostrophic dynamics characterized by an inverse energy cascade except for dissipation near the boundaries. In this paper, we confront dilemma of how may achieve dynamical equilibrium presence continuous large-scale forcing absence boundary dissipation. We do with a horizontal flow spatially uniform rotation, vertical...
Abstract The Gulf Stream strongly interacts with the topography along southeastern U.S. seaboard, between Straits of Florida and Cape Hatteras. dynamics in this region is investigated a set realistic, very high-resolution simulations using Regional Ocean Modeling System (ROMS). mean path influenced by particular Charleston Bump. There are significant local pressure anomalies topographic form stresses exerted bump that retard flow steer current pathway seaward. provides, through bottom...
The reflectance images of the oceanic surface are full surfactant lines created by velocity convergences, with typical line spacings 0.1–10 km, i.e., in submesoscale range. Here we propose a dynamical explanation process filamentary intensification that shrinks transverse scale rectilinear temperature extrema at super‐exponential rate action horizontal deformation flows associated mesoscale eddies. This is analogous to deformation‐induced frontogenesis sharpening gradients accelerated its...
Abstract A submesoscale filament of dense water in the oceanic surface layer can undergo frontogenesis with a secondary circulation that has horizontal convergence and downwelling its center. This occurs either because mesoscale straining deformation or boundary turbulence causes vertical eddy momentum flux divergence or, more briefly, mixing. In latter case approximately linear balance among baroclinic pressure gradient, Coriolis force, mixing, is, turbulent thermal wind. The frontogenetic...
Abstract Lateral stirring is a basic oceanographic phenomenon affecting the distribution of physical, chemical, and biological fields. Eddy at scales on order 100 km (the mesoscale) fairly well understood explicitly represented in modern eddy-resolving numerical models global ocean circulation. The same cannot be said for smaller-scale processes. Here, authors describe major field experiment aimed observing understanding processes responsible 0.1–10 km. Stirring varying intensity were...
Abstract The Gulf Stream (GS) is known to have a strong influence on climate, for example, by transporting heat from the tropics higher latitudes. Although GS transport intensity presents clear interannual variability, satellite observations reveal its mean path stable. Numerical models can simulate some characteristics of path, but persistent biases keep separation and postseparation unstable therefore unrealistic. This study investigates how integration ocean surface currents into...
Abstract Meanders and eddies are routinely observed in the Gulf Stream along South Atlantic Bight. We analyze here instability processes that lead to formation of submesoscale on cyclonic side at exit Florida Straits using very high resolution realistic simulations. The positive relative vorticity potential strongly intensified due topographic drag continental slope. bottom amplifies shear by generating large vertical values within sloped turbulent boundary layer. Downstream from current...
Abstract Frontal eddies are commonly observed and understood as the product of an instability Gulf Stream along southeastern U.S. seaboard. Here, authors study dynamics a simulated frontal eddy in South Atlantic Bight, including its structure, propagation, emergent submesoscale interior neighboring substructure, at very high resolution ( dx = 150 m). A rich structure is revealed inside eddy. Meander-induced frontogenesis sharpens gradients forms sharp fronts between adjacent Stream. The...
Recent technological developments have resulted in two techniques for estimating surface velocity with higher resolution than can be achieved from presently available nadir altimeter data: (1) Geostrophically computed estimates high-resolution sea height (SSH) measured interferometrically by the wide-swath on Surface Water and Ocean Topography (SWOT) Mission a planned launch 2021; (2) Measurements of ocean Doppler scatterometer mission that is early planning stages, referred to here as Winds...
Abstract Oceanic surface submesoscale currents are characterized by anisotropic fronts and filaments with widths from 100 m to a few kilometers; an O (1) Rossby number; large magnitudes of lateral buoyancy velocity gradients, cyclonic vorticity, convergence. We derive asymptotic model submeoscale frontogenesis—the rate sharpening gradients—and show that in contrast “classical” deformation frontogenesis, the near-surface convergent motions, which associated ageostrophic secondary circulation,...
Abstract The Persian Gulf feeds a warm and salty outflow in the of Oman (northern Arabian Sea). salt climatological distribution is relatively smooth Oman, signature slope current carrying waters difficult to distinguish hundreds kilometers past Strait Hormuz, contrast other outflows world ocean. This study focuses on mechanisms involved spreading Water (PGW) using regional primitive equation numerical simulation. authors show that dispersion PGW occurs through regime distinct from, for...
Abstract An idealized framework of steady barotropic flow past an isolated seamount in a background constant stratification (with frequency N ) and rotation Coriolis parameter f is used to examine the formation, separation, instability turbulent bottom boundary layers (BBLs), ultimately, genesis submesoscale coherent vortices (SCVs) ocean interior. The BBLs generate vertical vorticity ζ potential q on slopes; separates spawns shear layers; centrifugal instabilities form vortical filaments...
Photochemistry is studied in a convective atmospheric boundary layer. The essential reactions that account for the ozone formation and depletion are included chemical mechanism which, as consequence, contains wide range of timescales. turbulent reacting flow modeled with large‐eddy simulation (LES) code. deviations from equilibrium caused by motions investigated terms intensity segregation. For cases it found volume‐averaged concentrations calculated LES code agree well box model. reaction...
Abstract Fronts and eddies identified with aerial guidance are seeded drifters to quantify submesoscale flow kinematics. The Lagrangian observations show mean divergence vorticity values that can exceed 5 times the Coriolis frequency. Values largest observed in field date represent an extreme departure from geostrophic dynamics. study also quantifies errors biases associated of underlying velocity strain tensor. greatest error results undersampling, even a large number drifters. A...