Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Oceans

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 421 - 450 of 2515

Full-Text Articles in Entire DC Network

Tidal Fronts And Their Role In Air-Sea Gas Exchange, B. Baschek, D. M. Farmer, C. Garrett Jan 2006

Tidal Fronts And Their Role In Air-Sea Gas Exchange, B. Baschek, D. M. Farmer, C. Garrett

Journal of Marine Research

Tidal fronts are a common feature of many coastal environments. They are characterized by a surface convergence zone that enhances wave breaking and the generation of gas bubbles due to wave-current interaction. The associated downwelling currents carry bubbles to depths of up to 160 m and increase the amount of air that dissolves from them.An energetic tidal front is formed at the entrance to the Strait of Georgia, BC, Canada, by a hydraulically controlled sill flow with vertical velocities of up to 0.75 m s−1. Extensive ship-board measurements during two cruises are interpreted with models of wave-current interaction …

Go to article

Variation Beneath The Surface: Quantifying Complex Thermal Environments On Coral Reefs In The Caribbean, Bahamas And Florida, James J. Leichter, Brian Helmuth, Andrew M. Fischer Jan 2006

Variation Beneath The Surface: Quantifying Complex Thermal Environments On Coral Reefs In The Caribbean, Bahamas And Florida, James J. Leichter, Brian Helmuth, Andrew M. Fischer

Journal of Marine Research

Analysis of in situ temperature records collected on six coral reefs in the Caribbean, Bahamas, and Florida Keys reveal significant variability across a range of temporal and spatial scales from minutes to seasons, across depths, and among sites. Subsurface variability occurring at daily and faster frequencies is prevalent across the region, likely driven by combinations of diurnal heating and cooling, wind driven advection, and internal waves at tidal and faster frequencies. This high frequency variability is not detected in records of remotely-sensed sea surface temperature alone. Diurnal variability likely caused by diurnal solar heating and cooling and possibly by advection …

Go to article

A Model Of Methane Concentration Profiles In The Open Ocean, G. C. Nihous, S. M. Masutani Jan 2006

A Model Of Methane Concentration Profiles In The Open Ocean, G. C. Nihous, S. M. Masutani

Journal of Marine Research

Methane-bearing particulate matter formed in the upper ocean layer is allowed to settle and degrade, releasing methane into the water column as a source in one-dimensional advection-diffusion equations. Predicted carbon and methane particulate fluxes are in good agreement with sediment trap data, using parameters of expected magnitude and particulate methane production well within the mixed layer. This suggests a rapid pathway to the atmosphere and reduced effects on methane concentrations below. Vertical advection rates yielding a good fit between methane concentration calculations and data are larger than expected unless methane oxidation is included. This confirms the significance of methane oxidation …

Go to article

Inferring Mixed-Layer Depth Variability From Argo Observations In The Western Indian Ocean, T. V. S. Udaya Bhaskar, D. Swain, M. Ravichandran Jan 2006

Inferring Mixed-Layer Depth Variability From Argo Observations In The Western Indian Ocean, T. V. S. Udaya Bhaskar, D. Swain, M. Ravichandran

Journal of Marine Research

The seasonal and spatial variability of mixed layer depth (MLD) was examined in the Western Indian Ocean (WIO) (30E – 80E and 10S – 30N) for three consecutive years starting from June 2002 – May 2005 using Argo temperature and salinity (T/S) profiles. These were compared with MLD estimates from World Ocean Atlas 2001 (WOA01) T/S data. Temporal and spatial variability of MLD estimated from Argo T/S profiles were found to correspond well with the MLD obtained from WOA01 T/S data. However, slight deviations in the form of months of occurrence of minima and maxima MLDs were observed. MLD from …

Go to article

Bio-Irrigation In Permeable Sediments: An Assessment Of Model Complexity, Filip J. R. Meysman, Oleksiy S. Galaktionov, Britta Gribsholt, Jack J. Middelburg Jan 2006

Bio-Irrigation In Permeable Sediments: An Assessment Of Model Complexity, Filip J. R. Meysman, Oleksiy S. Galaktionov, Britta Gribsholt, Jack J. Middelburg

Journal of Marine Research

Burrowing benthic animals ventilate their burrow networks, and this enhances the transport of solutes in the sediment and exchange with the overlying water column, a process referred to as bio-irrigation. Various models have been proposed to model bio-irrigation, with different levels of sophistication related to model dimensionality and parameter numbers. Here we address the issue of model complexity for bio-irrigation in permeable sediments. To this end, we simulated flowline patterns and tracer signals using (1) a full 3D model that explicitly models the J-shaped geometry of the burrow in a suitable microenvironment surrounding the burrow, (2) a simplified 2D axisymmetric …

Go to article

Differential Fates Of Emiliania Huxleyi-Derived Fatty Acids And Alkenones In Coastal Marine Sediments: Effects Of The Benthic Crustacean Palaemonetes Pugio, Haibing Ding, Ming-Yi Sun Jan 2006

Differential Fates Of Emiliania Huxleyi-Derived Fatty Acids And Alkenones In Coastal Marine Sediments: Effects Of The Benthic Crustacean Palaemonetes Pugio, Haibing Ding, Ming-Yi Sun

Journal of Marine Research

In order to examine how benthic crustaceans affect the fates of phytoplankton-derived lipid biomarkers (fatty acids and alkenones) in coastal marine sediments, we incubated Emiliania huxleyi cells in microcosms (pre-sieved sediment cores with and without the grass shrimp Palaemonetes pugio ) over six weeks. Crustacean, transport of surface sediments, and distributions of algal lipids were followed during incubations. Crustacean activities enhanced degradation of algal fatty acids (2–4× faster) but had a small impact on algal alkenone degradation (<1.4×) compared to the controls. During the first few days of incubations, alkenone concentrations were enriched while algal fatty acid concentrations were depleted in suspended particles in the overlying water of cores, indicating that P. pugio selectively grazed algal material from sediments and preferentially assimilated fatty acids over alkenones through digestion. Unlike algal fatty acids, alkenones …

Go to article

Sandström’S Experiments Revisited, Melissa A. Coman, Ross W. Griffiths, Graham O. Hughes Jan 2006

Sandström’S Experiments Revisited, Melissa A. Coman, Ross W. Griffiths, Graham O. Hughes

Journal of Marine Research

Sandström's (1908, 1916) pioneering experiments led to the conclusion, later referred to as Sandström's 'theorem', that differential heating and cooling cannot drive a sustained circulation when the source of heating is at or above the level of the cooling source. This principle is incorrect on theoretical grounds and is contradicted by modern laboratory results for the particular case of differential heating and cooling along a single horizontal boundary of a box. However, the 'theorem' has remained common currency. In order to explain the contradiction and explore the fundamentally important concepts involved, we re-create the original experiments of a century ago. …

Go to article

Estimating Subsurface Horizontal And Vertical Velocities From Sea-Surface Temperature, J. H. Lacasce, A. Mahadevan Jan 2006

Estimating Subsurface Horizontal And Vertical Velocities From Sea-Surface Temperature, J. H. Lacasce, A. Mahadevan

Journal of Marine Research

We examine a dynamical method for estimating subsurface fields (density, pressure, horizontal and vertical velocities) in the upper ocean using sea-surface temperature (SST) and a climatological estimate of the stratification. The method derives from the "surface quasi-geostrophic" (SQG) approximation. The SST is used to generate a potential vorticity (PV) field which is then inverted for the pressure. We examine first the standard SQG model, in which the PV is assumed trapped in a delta-function layer at the surface. We then modify the model by introducing a subsurface PV which is proportional to the surface density and decays exponentially with depth. …

Go to article

Accounting For Unresolved Spatial Variability In Marine Ecosystems Using Time Lags, Philip J. Walhead, Adrian P. Martin, Meric A. Srokosz, Mike J. R. Fasham Jan 2006

Accounting For Unresolved Spatial Variability In Marine Ecosystems Using Time Lags, Philip J. Walhead, Adrian P. Martin, Meric A. Srokosz, Mike J. R. Fasham

Journal of Marine Research

The formulation and calibration of models is a vital method for probing and predicting the behavior of marine ecosystems. The ability to do this may suffer, however, if the calibrating data set is subject to significant spatial variability between samples that is not resolved in the model. We propose that some of this variability might be accounted for by variable time lags between sampled water masses which are otherwise assumed to follow a common pattern of ecosystem variability (dynamical trajectory). Using twin tests of fitting models to simulated data sets, we show that realistic levels of meso/sub-mesoscale variability in time …

Go to article

Linking Arenicola Marina Irrigation Behavior To Oxygen Transport And Dynamics In Sandy Sediments, Karen Timmermann, Gary T. Banta, Ronnie N. Glud Jan 2006

Linking Arenicola Marina Irrigation Behavior To Oxygen Transport And Dynamics In Sandy Sediments, Karen Timmermann, Gary T. Banta, Ronnie N. Glud

Journal of Marine Research

In this study we examine how the irrigation behavior of the common lugworm Arenicola marina affects the distribution, transport and dynamics of oxygen in sediments using microelectrodes, planar optodes and diagenetic modeling. The irrigation pattern was characterized by a regular recurring periods of active irrigation lasting approximately 15 min separated by a 15 min rest period. The mean pumping rate during irrigation was 52 ml h−1. Oxygen dynamics and distribution around the tail shaft was closely related to irrigation pattern but independent of pumping rate. During irrigation the oxygen concentration in the burrow was high (>80% air …

Go to article

Corrigendum To Diffusivity And Viscosity Dependence In The Linear Thermocline (J. Mar. Res., 62, 743–769), J. H. Lacasce Jan 2006

Corrigendum To Diffusivity And Viscosity Dependence In The Linear Thermocline (J. Mar. Res., 62, 743–769), J. H. Lacasce

Journal of Marine Research

The statement in LaCasce (2004) that the amplitude, A, of the western boundary layer solution (Eq. 25 in the article) is determined by matching at the northern wall to the streamfunction from the northern boundary inner layer solution, ϕin, is incorrect. The correct procedure is to match to the full boundary layer solution at the northern wall, with contributions from both the inner and outer layers. Doing this ensures that the full transport in the northern layer is fed into the western layer...

Go to article

Tidal Energy In The Bering Sea, M. G. G. Foreman, P. F. Cummins, J. Y. Cherniawsky, Phyllis Stabeno Jan 2006

Tidal Energy In The Bering Sea, M. G. G. Foreman, P. F. Cummins, J. Y. Cherniawsky, Phyllis Stabeno

Journal of Marine Research

Tidal harmonics computed from TOPEX/POSEIDON altimetry are assimilated into a barotropic, finite element model of the Bering Sea whose accuracy is evaluated though comparisons with independent bottom pressure gauges. The model is used to estimate energy fluxes through each of the Aleutian Passes and Bering Strait and to construct an energy budget for the major tidal constituents. The finite element model does not conserve mass locally and this is shown to give rise to an additional term in the energy budget whose contribution is significant for the prior model, but which is reduced substantially with the assimilation technique. Though the …

Go to article

Estimation Of Nonlocal Turbulent Mixing Parameters Derived From Microstructure Profiles, Jaume Piera, Ruben Quesada, Jordi Catalan Jan 2006

Estimation Of Nonlocal Turbulent Mixing Parameters Derived From Microstructure Profiles, Jaume Piera, Ruben Quesada, Jordi Catalan

Journal of Marine Research

The present study proposes a new method for estimating nonlocal mixing parameters from microstructure data processing. The method could be particularly useful in studies of biological-physical interactions at small scale because it overcomes some of the limitations of the eddy diffusivity concept when dealing with the complex vertical pattern of biological and chemical tracers. The proposed method obtains empirically the coefficients of the transilient matrix, this being the discrete descriptor used in nonlocal mixing closure. The estimation is based on microstructure data analysis, in particular Thorpe displacement profiles, and includes three main steps: turbulent patch identification within each profile, turbulent …

Go to article

Transfer Of Particulate Matter From The Northwestern Mediterranean Continental Margin: Variability And Controlling Factors, M. Guarracino, B. Barnier, P. Marsaleix, X. Durrieu De Madron, A. Monaco, K. Escoubeyrou, J. C. Marty Jan 2006

Transfer Of Particulate Matter From The Northwestern Mediterranean Continental Margin: Variability And Controlling Factors, M. Guarracino, B. Barnier, P. Marsaleix, X. Durrieu De Madron, A. Monaco, K. Escoubeyrou, J. C. Marty

Journal of Marine Research

Long-term observations of monthly downward particle fluxes and hourly currents and temperature were initiated in 1993 in two canyons of the continental margin of the Gulf of Lion. The goals of this survey were to estimate its contribution to the CO2 global budget and to understand the role of forcing factors in the control of present-day particle exchange across this margin. A previous statistical analysis of the long-term time series suggested that variability in the transfer of particulate matter to the deep ocean could be the result of the effect of the meandering of the Northern Current and by …

Go to article

Quantifying Seasonal Air-Sea Gas Exchange Processes Using Noble Gas Time-Series: A Design Experiment, Rachel H. R. Stanley, William J. Jenkins, Scott C. Doney Jan 2006

Quantifying Seasonal Air-Sea Gas Exchange Processes Using Noble Gas Time-Series: A Design Experiment, Rachel H. R. Stanley, William J. Jenkins, Scott C. Doney

Journal of Marine Research

A multi-year time-series of measurements of five noble gases (He, Ne, Ar, Kr, and Xe) at a subtropical ocean location may allow quantification of air-sea gas exchange parameters with tighter constraints than is currently available by other methods. We have demonstrated this using a one-dimensional upper ocean model forced by 6-hourly NCEP reanalysis winds and heat flux for the Sargasso Sea near Bermuda. We performed ensemble model runs to characterize the response of the modeled noble gas saturation anomalies to a range of air-sea gas exchange parameters. We then used inverse calculations to quantify the sensitivity of the parameters to …

Go to article

Synoptic Lagrangian Maps: Application To Surface Transport In Monterey Bay, B. L. Lipphardt Jr., D. Small, A. D. Kirwan Jr., S. Wiggins, K. Ide, C. E. Grosch, J. D. Paduan Jan 2006

Synoptic Lagrangian Maps: Application To Surface Transport In Monterey Bay, B. L. Lipphardt Jr., D. Small, A. D. Kirwan Jr., S. Wiggins, K. Ide, C. E. Grosch, J. D. Paduan

Journal of Marine Research

Here we report on an effort to describe in detail the evolution of surface water particles in Monterey Bay from the time they first enter until the time they leave. The data used for this study are objective mappings from hourly surface currents obtained from high frequency (HF) radar measurements in Monterey Bay for the period 2 June through 4 August 1999. The basic concept is simple: compute the origin and fate of a large number of particles for every hour during the analysis period. However, analyzing and displaying the enormous amount of computed trajectory information required a new data …

Go to article

Beam Attenuation And Chlorophyll Concentration As Alternative Optical Indices Of Phytoplankton Biomass, Michael J. Behrenfeld, Emmanual Boss Jan 2006

Beam Attenuation And Chlorophyll Concentration As Alternative Optical Indices Of Phytoplankton Biomass, Michael J. Behrenfeld, Emmanual Boss

Journal of Marine Research

Chlorophyll has long functioned as the prominent field metric for phytoplankton biomass, but its variability can be strongly influenced by (even dominated by) physiological shifts in intracellular pigmentation in response to changing growth conditions (light, nutrients, temperature). The particulate beam attenuation coefficient (cp) may offer an alternative optical measure of phytoplankton biomass that is readily assessed in situ and relatively insensitive to changes in intracellular pigment content. Unlike chlorophyll, however, cp is not uniquely associated with phytoplankton and varies as well with changes in inorganic, detrital, and heterotrophic particles. In open ocean environments, particles in the …

Go to article

Does The Marine Biosphere Mix The Ocean?, W. K. Dewar, R. J. Bingham, R. L. Iverson, D. P. Nowacek, L. C. St. Laurent, P. H. Wiebe Jan 2006

Does The Marine Biosphere Mix The Ocean?, W. K. Dewar, R. J. Bingham, R. L. Iverson, D. P. Nowacek, L. C. St. Laurent, P. H. Wiebe

Journal of Marine Research

Ocean mixing is thought to control the climatically important oceanic overturning circulation. Here we argue the marine biosphere, by a mechanism like the bioturbation occurring in marine sediments, mixes the oceans as effectively as the winds and tides. This statement is derived ultimately from an estimated 62.7 TeraWatts of chemical power provided to the marine environment in net primary production. Various approaches argue something like 1% (.63 TeraWatts) of this power is invested in aphotic ocean mechanical energy, a rate comparable to wind and tidal inputs.

Go to article

Acoustic Observations Of Vertical And Horizontal Swimming Velocities Of A Diel Migrator, C. Smyth, A. E. Hay, P. S. Hill, D. Schillinger Jan 2006

Acoustic Observations Of Vertical And Horizontal Swimming Velocities Of A Diel Migrator, C. Smyth, A. E. Hay, P. S. Hill, D. Schillinger

Journal of Marine Research

A strong sound scattering layer which underwent diel vertical migration was observed over 176 days using a bottom-mounted 600 kHz ADCP at a depth of approximately 285 m on the upper continental slope. Average observed descent times of the scatterers were within 12 minutes of sunrise and average ascent times were within 13 minutes of sunset. Average ascent speeds progressively increased away from the bed and approached 6 cm/s. Average descent speeds similarly reached a maximum of ∼6 cm/s. Horizontal velocities of the scatterers during vertical migration were found to be smaller than ambient velocities (by up to 3 cm/s), …

Go to article

Estimation Of Mixed-Layer Depth From Surface Parameters, D. Swain, M. M. Ali, R. A. Weller Jan 2006

Estimation Of Mixed-Layer Depth From Surface Parameters, D. Swain, M. M. Ali, R. A. Weller

Journal of Marine Research

Mixed layer depth (MLD) is an important oceanographic parameter. However, the lack of direct observations of MLD hampers both specification and investigation of its spatial and temporal variability. An important alternative to direct observation would be the ability to estimate MLD from surface parameters easily available from satellites. In this study, we demonstrate estimation of MLD using Artificial Neural Network methods and surface meteorology from a surface mooring in the Arabian Sea. The estimated MLD had a root mean square error of 7.36 m and a coefficient of determination (R2) of 0.94. About 67% (91%) of the …

Go to article

Understanding The Influence Of Rossby Waves On Surface Chlorophyll Concentrations In The North Atlantic Ocean, G. Charria, I. Dadou, P. Cipollini, M. Drévillon, P. De Mey, V. Garçon Jan 2006

Understanding The Influence Of Rossby Waves On Surface Chlorophyll Concentrations In The North Atlantic Ocean, G. Charria, I. Dadou, P. Cipollini, M. Drévillon, P. De Mey, V. Garçon

Journal of Marine Research

The variability (in space and time) of westward propagating Rossby waves is analyzed with a wavelet method between 10N and 40N in the North Atlantic Ocean using two remotely sensed data sets (Sea Level Anomalies – SLA and surface chlorophyll-a concentrations) in order to better understand the waves' characteristics and their impacts on the chlorophyll distribution. Signals with wavelengths between ∼ 500 km and ∼ 1000 km with ∼ 4- to ∼ 24-month periods were detected and identified as the first baroclinic mode of Rossby waves. The spatial and temporal information has also highlighted a particular situation in 1998 …

Go to article

Simulation And Energy Partition Of The Flow Through Paso Galvarino, Chile, Michael W. Stacey, Arnoldo Valle-Levinson Jan 2006

Simulation And Energy Partition Of The Flow Through Paso Galvarino, Chile, Michael W. Stacey, Arnoldo Valle-Levinson

Journal of Marine Research

Paso Galvarino is a constriction in Seno Ventisquero, a tidally-energetic Chilean fjord. The pass is about 1500 m long and constricts in width by about 90 % near its sill, which has a depth of about 8 m. A laterally-averaged numerical model is compared to ADCP and backscatter observations of the hydraulic flow near the sill, during maximum flood, the slack tide after the flood, maximum ebb, and the slack tide after the ebb. The model is also used to examine how the energy flux into the fjord is partitioned in the region of the constriction. Energy is removed from …

Go to article

The Evolution Of Density Currents And Nepheloid Bottom Layers In The Ross Sea (Antarctica), Giorgio Budillon, Ettore Salusti, Sergio Tucci Jan 2006

The Evolution Of Density Currents And Nepheloid Bottom Layers In The Ross Sea (Antarctica), Giorgio Budillon, Ettore Salusti, Sergio Tucci

Journal of Marine Research

In this study we have analyzed the thermohaline, light transmission and particulate matter data, obtained in the western sector of the Ross Sea during the X Italian Expedition, for the purpose of investigating the evolution of the High Salinity Shelf Water in this area. In particular CTD data were used to estimate the baroclinic velocity field. Light transmission and total particulate matter data (from Niskin bottles mounted on a Carousel water sampler) were used to analyze the nepheloid layers and the evolution of the suspended sediments. This basin is characterized by a northward flow of very dense High Salinity Shelf …

Go to article

Sensitivity Of The Meridional Transport In A 1.5-Layer Ocean Model To Localized Mass Sources, C. Herbaut, J. Sirven, J. Deshayes Jan 2006

Sensitivity Of The Meridional Transport In A 1.5-Layer Ocean Model To Localized Mass Sources, C. Herbaut, J. Sirven, J. Deshayes

Journal of Marine Research

The response of a 1.5-layer ocean model forced by localized stochastic mass sources is studied. The focus is on the sensitivity of the spectral characteristics of the meridional transport to the location and the extent of the source region. In all the experiments, performed in hemispheric and interhemispheric basins, the spectra show a peak at interannual time scale revealing the existence of an oscillation. The period of the oscillation is defined by the zonal extent of the forcing, whereas its amplitude is affected by its location. When the source region is located in the northwestern corner of the basin, the …

Go to article

Variability In The Indian Ocean Circulation And Salinity And Its Impact On Sst Anomalies During Dipole Events, Bijoy Thompson, C. Gnanaseelan, P. S. Salvekar Jan 2006

Variability In The Indian Ocean Circulation And Salinity And Its Impact On Sst Anomalies During Dipole Events, Bijoy Thompson, C. Gnanaseelan, P. S. Salvekar

Journal of Marine Research

The GFDL Modular Ocean Model (MOM4) has been used to understand the variability of the Indian Ocean circulation and salinity during Indian Ocean Dipole events. The model simulations are compared with HadISST, SODA and ECCO data sets. During the positive dipole years, the climatological cyclonic circulation in the Bay of Bengal weakens or is replaced by an anticyclonic circulation. The interannual variability in the Wyrtki Jet and Bay of Bengal circulation has significant influence on fresh water transport between the equatorial Indian Ocean and Bay of Bengal. The salinity anomalies in the equatorial Indian Ocean are significant during the positive …

Go to article

Critical Effects Of A Tall Seamount On A Drifting Vortex, Georgi G. Sutyrin Jan 2006

Critical Effects Of A Tall Seamount On A Drifting Vortex, Georgi G. Sutyrin

Journal of Marine Research

The initial-value problem for the evolution of an isolated vortex encountering a tall seamount during its westward beta-drift is studied within an equivalent-barotropic model, that is generalized to allow for the intersection of the layer interface with a sloping bottom. Given the Rossby radius and linear wave speed in the model, the parabolic shape of a seamount top and initial potential vorticity profile in the vortex core, the outcome is controlled by the vortex sign and a number of parameters: the seamount radius and height of penetration into the active layer, the radius and intensity of the vortex, the initial …

Go to article

Identifiability And Uncertainty Analysis Of Bio-Irrigation Rates, Johan H. Andersson, Jack J. Middelburg, Karline Soetaert Jan 2006

Identifiability And Uncertainty Analysis Of Bio-Irrigation Rates, Johan H. Andersson, Jack J. Middelburg, Karline Soetaert

Journal of Marine Research

Bio-irrigation is often quantified through incubations where an inert tracer is added to the overlying water of a core or a benthic chamber, and subsequently following the tracer distribution in either the overlying water or the porewater. The interpretation is based on fitting data with a model containing several unknown parameters such as the enhancement over molecular diffusion or non-local exchange. In this paper, we test under what conditions the results obtained through this fitting are robust. We first use identifiability analysis to investigate the minimum data requirements for two types of sediments, representative for deep-sea and shallow-water settings. We …

Go to article

Cluster Analysis For Physical Oceanographic Data And Oceanographic Surveys In Turkish Seas, Derya Birant, Alp Kut Jan 2006

Cluster Analysis For Physical Oceanographic Data And Oceanographic Surveys In Turkish Seas, Derya Birant, Alp Kut

Journal of Marine Research

Cluster analysis is a useful data mining method to obtain detailed information on the physical state of the ocean. The primary objective of this study is the development of a new spatio-temporal density-based algorithm for clustering physical oceanographic data. This study extends the regular spatial cluster analysis to deal with spatial data at different epochs. It also presents the sensitivity of the new algorithm to different parameter settings. The purpose of the sensitivity analysis presented in this paper is to identify the response of the algorithm to variations in input parameter values and boundary conditions. In order to demonstrate the …

Go to article

Variability Of The Subantarctic And Polar Fronts In The Drake Passage As Deduced From Altimetry, Nadine Chouaib, Felix Stoehr, Christine Provost Jan 2006

Variability Of The Subantarctic And Polar Fronts In The Drake Passage As Deduced From Altimetry, Nadine Chouaib, Felix Stoehr, Christine Provost

Journal of Marine Research

The magnitude and time variability of the total volume transport of the Antarctic Circumpolar Current through Drake Passage is a key climatic index, yet still uncertain. We processed ten years of TOPEX/Poseïdon data along two adjacent descending tracks in Drake Passage assuming (following Gille, 1994) that the surface current velocity has a profile structure of double Gaussian jets corresponding respectively to the Subantarctic Front (SAF) and the Polar Front (PF). We seek the location, width and intensity of each jet as a function of time. Results from the two tracks are coherent and show that the time evolution of the …

Go to article

A Tribute To Nick Fofonoff, Sears Foundation Of Marine Research Yale University Jan 2005

A Tribute To Nick Fofonoff, Sears Foundation Of Marine Research Yale University

Journal of Marine Research

Biographical Notes: Nick Fofonoff

Go to article

First Prev Next Last