A5024310254- Oceanographic and Atmospheric Processes
- Ocean Waves and Remote Sensing
- Climate variability and models
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Arctic and Antarctic ice dynamics
- Atmospheric and Environmental Gas Dynamics
- Underwater Acoustics Research
- Tropical and Extratropical Cyclones Research
- Methane Hydrates and Related Phenomena
- Meteorological Phenomena and Simulations
- Geophysics and Gravity Measurements
- Marine and fisheries research
- Geological and Geophysical Studies
- Marine animal studies overview
- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Geomagnetism and Paleomagnetism Studies
- Reservoir Engineering and Simulation Methods
- Magnetic confinement fusion research
- Offshore Engineering and Technologies
- Hydrocarbon exploration and reservoir analysis
- Geological formations and processes
- Coastal and Marine Dynamics
- Polar Research and Ecology
Scripps Institution of Oceanography
2012-2025
University of California, San Diego
2012-2025
NOAA Pacific Marine Environmental Laboratory
2001
University of Alaska Fairbanks
2000
National Institute of Water and Atmospheric Research
2000
Oregon State University
1985-1987
University of Cambridge
1986
Massachusetts Institute of Technology
1985
Abstract Internal wave–wave interaction theories and observations support a parameterization for the turbulent dissipation rate ɛ eddy diffusivity K that depends on internal wave shear 〈Vz2〉 strain 〈ξz2〉 variances. Its latest incarnation is applied to about 3500 lowered ADCP/CTD profiles from Indian, Pacific, North Atlantic, Southern Oceans. Inferred diffusivities are functions of latitude depth, ranging 0.03 × 10−4 m2 s−1 within 2° equator (0.4–0.5) at 50°–70°. Diffusivities also increase...
Abstract This study discusses the upper-ocean (0–200 m) horizontal wavenumber spectra in Drake Passage from 13 yr of shipboard ADCP measurements, altimeter data, and a high-resolution numerical simulation. At scales between 10 200 km, kinetic energy approximately follow k −3 power law. The observed flows are more energetic at surface, but shape is independent depth. These characteristics resemble predictions isotropic interior quasigeostrophic turbulence. ratio across-track to along-track...
Abstract The Antarctic Circumpolar Current is an important component of the global climate system connecting major ocean basins as it flows eastward around Antarctica, yet due to paucity data, remains unclear how much water transported by current. Between 2007 and 2011 flow through Drake Passage was continuously monitored with a line moored instrumentation unprecedented horizontal temporal resolution. Annual mean near‐bottom currents are remarkably stable from year year. depth‐independent or...
In 2018 we celebrated 25 years of development radar altimetry, and the progress achieved by this methodology in fields global coastal oceanography, hydrology, geodesy cryospheric sciences. Many symbolic major events have these developments, e.g., Venice, Italy, 15th (2006) 20th (2012) more recently, 2018, Ponta Delgada, Portugal, Years Progress Radar Altimetry. On latter occasion it was decided to collect contributions scientists, engineers managers involved worldwide altimetry community...
Abstract Recent studies show that the vigorous seasonal cycle of mixed layer modulates upper ocean submesoscale turbulence. Here we provide model‐based evidence seasonally changing stratification in Kuroshio Extension also (here 10–100 km) inertia‐gravity waves. Summertime restratification weakens turbulence but enhances waves near surface. Thus, and undergo out‐of‐phase cycles. These results imply a strong modulation accuracy geostrophic velocity diagnosed from sea surface height delivered...
Drake Passage is the narrowest constriction of Antarctic Circumpolar Current (ACC) in Southern Ocean, with implications for global ocean circulation and climate. We review long‐term sustained monitoring programs that have been conducted at Passage, dating back to early part twentieth century. Attention drawn numerous breakthroughs made from these programs, including (1) first determinations complex ACC structure quantifications its transport; (2) realization transport remarkably steady over...
Moored acoustic Doppler current profiler velocity estimates and buoy wind observations made during a period of moderate southward winds were used to test the Ekman balance at site in California Current. As prior studies, wind‐driven flow was separated from total by subtraction deep reference current. The shown be an on daily timescales over several months. mean observed transport right agreed within 3% magnitude 4° phase with predicted transport, although error bar about 20%. profile smooth...
[1] The structure of the Antarctic Circumpolar Current (ACC) in Drake Passage is examined using 4.5 years shipboard acoustic Doppler current profiler (ADCP) velocity data. extended 1000 m depth range available from 38 kHz ADCP allows us to investigate vertical current. mean observed varies slowly with depth, while eddy kinetic energy and shear variance exhibit strong dependence. Objectively mapped streamlines are self-similar consistent an equivalent barotropic structure. Vertical wavenumber...
Abstract During the 2005 austral winter (late August–early October) and 2006 summer (February–mid-March) two intensive hydrographic surveys of southeast Pacific sector Southern Ocean were completed. In this study turbulent kinetic energy dissipation rate ε, diapycnal diffusivity κ, buoyancy flux Jb are estimated from CTD/O2 XCTD profiles for each survey. Enhanced κ O(10−3 to 10−4 m2 s−1) is found near Subantarctic Front (SAF) during both surveys. survey, enhanced was also observed north...
Two hydrographic surveys and a one‐dimensional mixed layer model are used to assess the role of air‐sea fluxes in forming deep Subantarctic Mode Water (SAMW) layers southeast Pacific Ocean. Forty‐two SAMW deeper than 400 m were observed north Front during 2005 winter cruise, with deepest reaching 550 m. The densest, coldest, freshest found cruise's eastern sections near 77°W. concurrently surface ocean heat loss approximately −200 W −2 . heat, momentum, precipitation flux fields five...
Abstract Since the inception of international South Atlantic Meridional Overturning Circulation initiative in 21st century, substantial advances have been made observing and understanding Southern Hemisphere component (AMOC). Here we synthesize insights gained into overturning flows, interocean exchanges, water mass distributions pathways Atlantic. The circulation uniquely carries heat equatorward exports freshwater poleward consists two strong cells. Density pressure gradients, winds,...
Low‐pass‐filtered velocities obtained from World Ocean Circulation Experiment (WOCE) surface drifters deployed in the California Current off northern during 1993–1995 have been compared with geostrophic velocity estimates made along subtracks of TOPEX/POSEIDON altimeter and moored acoustic Doppler current profiler (ADCP) data. To obtain absolute velocities, a mean sea height (SSH) field was estimated using drifter historical hydrographic data added to altimetric SSH anomalies. The...
Abstract Largely zonal winds in the Southern Ocean drive an equatorward Ekman transport that constitutes shallowest limb of meridional overturning circulation Antarctic Circumpolar Current (ACC). Despite its importance, there have been no direct observations open ocean balance until now. Using high-resolution repeat upper-ocean velocity Drake Passage, a mean spiral is resolved and computed. The currents decay amplitude rotate anticyclonically with depth, penetrating to ∼100-m above base...
Observations of stratified tidal flow over a submarine ridge indicate that the large amplitude and asymmetry topography are critical in determining type response. The observations consist hydrographic, current meter, echo‐sounding data used as basis for inferring generation mechanism previously observed trains internal waves. response on ebb flood tide is categorized according to Froude number classification sill flows proposed by Farmer Smith (1980 ). calculated numbers, length scale,...
Abstract As observations and models improve their resolution of oceanic motions at ever finer horizontal scales, interest has grown in characterizing the transition from geostrophically balanced flows that dominate large‐scale to submesoscale turbulence waves small scales. In this study we examine mesoscale‐to‐submesoscale (100 10 km) an eastern boundary current, southern California Current System (CCS), using repeated acoustic Doppler current profiler transects, sea surface height...
A pair of high‐resolution oceanographic surveys in March and April 1995 revealed a large rapid transition from late winter to spring conditions the coastal zone off central southern California. These data are unique capturing detailed three‐dimensional physical structure biological response California Current System (CCS). Changes associated with included strong tilting isopycnals, which lifted by up 60 m near coast dropped 20–40 offshore, subsequent increase cross‐shore density gradients,...
A comparison of measured and wind-derived ageostrophic transport is presented from a zonal transect spanning the Atlantic Ocean along 11°N. The per unit depth shows striking surface maximum that decays to nearly zero at approximately 100 m. We identify this flow in upper m as Ekman transport. sustained values wind stress penetration reported here are considerably greater than previous observations, which were made conditions light winds. 12.0 ± 5.5 × 106 m3 s−1, calculated difference...
Abstract Recent observations taken at four principal latitudes in the Agulhas Current show that watermass properties on either side of its dynamical core are significantly different. Inshore velocity found waters predominantly Arabian Sea, Red and equatorial Indian Ocean origin, while offshore generally from Atlantic Ocean, Southern southeast Ocean. For most part, inshore approach through Mozambique Channel, those circulated within southern subtropical gyre before joining current. These...
Observations from 38 bottom‐moored Current and Pressure Recording Inverted Echo Sounders (CPIES) deployed in Drake Passage during the 2007–2008 International Polar Year provide unprecedented coverage of near‐bottom currents pressures spanning entire Antarctic Circumpolar Current. Year‐long‐mean exceed 10 cm s −1 north Front, mean directions are not, general, aligned with surface fronts. Topographic steering is most evident at continental margins. Deep eddy kinetic energy (EKE) maximum about...
Net fluxes of mass, heat, salt, nutrients, oxygen, and chlorophyll into a control volume within the southern California Current System (CCS) were computed from data collected on 55 cruises over 14 year period (1984–1997). This analysis builds an earlier work [ Roemmich , 1989] by using additional 39 10 years, allowing for reliable estimates temporal variability in seasonal interannual timescales reduction corresponding error budgets. A close balance was found between geostrophic convergence...
The conventional view of equatorial dynamics requires that the zonal wind stress be balanced, in mean, by vertical integral "large-scale" terms, such as pressure gradient, mesoscale eddy flux, and mean advection, over upper few hundred meters. It is usually presumed surface communicated to interior turbulent processes. Turbulent kinetic energy dissipation rates measured at 140°W during TROPIC HEAT I experiment a production rate–dissipation rate balance argument have been used calculate 30 90...
The magnitude, location, and extent of the California Undercurrent (CUC) off southern is investigated using cruises Cooperative Oceanic Fisheries Investigations (CalCOFI) from 1993 to 2003 which provide hydrographic, biochemical, acoustic Doppler current profiler (ADCP) velocity data on a quarterly basis. This study first use decade‐long ADCP time series; it improves prior geostrophic calculations by providing an absolute reference for estimates currents transport. long‐term mean reveals two...
Abstract We diagnose the Southern Ocean momentum balance in a 6 year, eddy‐permitting state estimate of Ocean. find that 95% zonal input via wind stress at surface is balanced by topographic form across ocean ridges, while remaining 5% bottom friction and flux divergences northern southern boundaries analysis domain. While time‐mean field exhibits relatively uniform spatial distribution, concentrates shallow ridges continents lie within Antarctic Circumpolar Current (ACC) latitudes; nearly...