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1998

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The Influence Of The Ambient Flow On The Spreading Of Convected Water Masses, Sonya Legg, John Marshall Jan 1998

The Influence Of The Ambient Flow On The Spreading Of Convected Water Masses, Sonya Legg, John Marshall

Journal of Marine Research

We investigate the influence of a cyclonic vortical flow on the lateral spreading of newly mixed fluid generated through localized deep convection. Localized open ocean deep convection often occurs within such a cyclonic gyre circulation, since the associated upwardly domed isopycnals and weaker stratification locally precondition the ocean for deeper convection. In the absence of ambient flow, localized convection has been shown to result in strong lateral fluxes of buoyancy generated by baroclinic instability, sufficient to offset the local surface buoyancy loss and limit the density anomaly of the convectively generated water mass. Here we examine the consequences of a …

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The Southern Flux Of Sea Ice In The Tatarskiy Strait, Japan Sea And The Generation Of The Liman Current, Seelye Martin, Mitsuhiro Kawase Jan 1998

The Southern Flux Of Sea Ice In The Tatarskiy Strait, Japan Sea And The Generation Of The Liman Current, Seelye Martin, Mitsuhiro Kawase

Journal of Marine Research

The circulation in the surface waters of the Japan Sea is driven in part by thermohaline forcing associated with the flux of cold, low-salinity water from the Tatarskiy Strait. Existing numerical models suggest that this water contributes to the Liman Current, which flows from northeast to southwest along the Russian coast. The major source of Japan Sea freshwater is the Amur River, which flows into the sea through Tatarskiy Strait, but has a near-zero minimum during January to March. As an alternate source of freshwater to the surface layer, we derive from meteorological and remote sensing data for the 1992-1994 …

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Corrigendum To Surface-Intensified Rossby Waves Over Rough Topography (J. Mar. Res., 50, 367–384), R. M. Samelson Jan 1998

Corrigendum To Surface-Intensified Rossby Waves Over Rough Topography (J. Mar. Res., 50, 367–384), R. M. Samelson

Journal of Marine Research

In Samelson (1992), Eq. (13) should be changed to… respectively. The same error appears in the Abstract.

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Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren Jan 1998

Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren

Journal of Marine Research

Moored current meters, fluorom eters and transmissometers were used in combination with sediment traps (aspect ratio >4) and shipborne sampling to determine fluxes of deposition and resuspension of total suspended matter (TSM) under tidal action in the 45 m deep Oyster Grounds, North Sea. Here, we present data from the mixed layer below the major thermocline at about 20 m above the bottom (mab) as obtained during a 14-day period of calm weather in July 1994. Around neap tide near-bottom current velocities remained smaller than 0.15 m s-1 and TSM was dominated by particles advected from a relatively turbid …

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Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp Jan 1998

Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp

Journal of Marine Research

The inundation of two moored platforms by sea ice in late winter and early spring of 1995 provided unique time series of water column temperature, salinity, estimated chlorophyll-a, and phytoplankton fluorescence under advancing and retreating sea ice. One platform was located at 72 m in the weakly advective middle shelf regime. Here, chlorophyll-a concentrations began increasing shortly after the arrival of the ice (arch) during the period of weak stratification and continued to increase while wind actively mixed the water column to >60 m. Changes in water column structure and properties resulted from an event of strong …

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Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson Jan 1998

Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson

Journal of Marine Research

Observations of water properties and deep currents over several trenches in the Pacific Ocean central basins give consistent evidence for recent ventilation of water below the trench sills and cyclonic sense of circulation over the trenches. A dynamical argument for this pattern is advanced. First, a review of previous analyses of hydrographic data shows that the trenches are well ventilated by dense bottom water, that within the trenches this bottom water generally spreads away from its source, and that a cyclonic sense of circulation is suggested over some trenches. Then, this cyclonic sense of circulation over the trenches is further …

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A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson Jan 1998

A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson

Journal of Marine Research

The evolution of fingers in a double-diffusive system is investigated using numerical integration of two-dimensional equations of motion for an incompressible, Boussinesq fluid. The computational domain is periodic in the horizontal direction and is closed with no-flux boundary conditions in the vertical direction. The main result of this study is the evolution of the system from initially linear profiles for both fast and slow diffusing components to a layered state characterized by a finger zone sandwiched between two mixed layers. The horizontal boundaries in this system play an important role in the development of the layered state. At the top …

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The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout Jan 1998

The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout

Journal of Marine Research

Within a quasi-geostrophic two-layer model of the wind-driven ocean circulation, an idealized symmetric double gyre flow is considered. When lateral friction is large enough, this flow is steady and characterized by a motionless lower layer. As friction is decreased, the flow undergoes a transition to time-dependence through a Hopf bifurcation, associated with a mixed barotropic/baroclinic instability. It is shown that the nonlinear self-interaction of this oscillatory unstable mode induces a nonzero time mean response in the lower layer. The origin of this deep flow is clarified through a weakly nonlinear analysis near critical conditions. It is explained how the perturbation …

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Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay Jan 1998

Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay

Journal of Marine Research

The most biologically and geochemically active marine sediments are characterized by steep chemical gradients within the top centimeters of sediment (Berner, 1980). A common feature of these environments is disruptions of surface sediments by both physical and biotic forces. Growth and mortality rates for new recruits are affected by many of these surface perturbations. At the same time, these disturbances also impose a discontinuity in concentration across the sediment-water interface, and accordingly, a change in surface chemistry. In this paper we present evidence that the cue used by juveniles to distinguish between recently disturbed and undisturbed surfaces may be disruption …

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Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush Jan 1998

Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush

Journal of Marine Research

Measurements of seabed drag coefficient, C100, were made under tidal currents at four sites in Mahurangi Harbour, New Zealand. At the first three sites the dominant roughness element was the pinnid bivalve, Atrina zelandica (horse mussel). At the fourth site, which was devoid of horse mussels but covered in cockle shells, patches of seaweed and crab burrows, C100 was smallest (0.0055), but still twice as large as the value typically applied to abiotic, flat, cohesionless seabeds (0.0025). The mean drag coefficient plus-or-minus standard error at the three sites with horse mussels was: 0.0082 ± 0.0010 (site 1); …

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Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua Jan 1998

Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua

Journal of Marine Research

This study investigates the stirring of the thermohaline anomalies in a fully turbulent quasigeostrophic stratified flow. Temperature and salinity fields are permanently forced at large scales and are related to density by a linear equation of state. We show, using some inherent properties of quasi-geostrophic turbulence, that the 3-D ageostrophic circulation is the key dynamical characteristic that governs the strength and the spatial distribution of small-scale thermohaline fronts that are strongly density compensated. The numerical simulations well illustrate the formation by the mesoscale eddy field of sharp thermohaline fronts that are mainly located in the saddle regions and around the …

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Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques Jan 1998

Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques

Journal of Marine Research

The results of a year-long sediment-trap experiment provide the first direct observations of sediment fluxes to the seafloor on the Barcelona continental margin. Time-series of vertical particle fluxes and major constituents (organic carbon, biogenic silica, calcium carbonate and aluminosilicates) were determined inside and in the vicinity of the Foix submarine canyon from May 1993 to April 1994. The spatial and temporal variability of bi-weekly total mass fluxes indicate significant high frequency variability related to physical and biological processes at this site. The Foix submarine canyon acts as an actual conduit for transport of sediment from the shelf to the slope, …

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Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher Jan 1998

Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher

Journal of Marine Research

We measured the physiological turnover rate (= excretion rate) of five trace elements (Ag, Cd, Co, Se and Zn) in the marine copepod Temora longicornis following feeding on radiolabeled diatoms. The turnover rate constants of trace elements in copepods were high (0.05 to 0.38 d-1) and were comparable to published values for N and P excretion. Ag, Cd and Co were excreted at higher rates than Se and Zn. Turnover rate constants of Ag, Cd, and Co also increased with increasing food concentration, whereas excretion of Se and Zn was not affected by food concentration. There was little …

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The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady Jan 1998

The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady

Journal of Marine Research

An overlooked aspect of continental shelf wave generation by wind is that a non-wavelike flow field may accompany the waves. To explore this possibility, we calculate the response of an inclined plane shelf to suddenly applied alongshore wind, affecting a finite portion of the coast. The calculations are based on the classical theory of continental shelf waves, supposing low frequency motions and invoking the boundary layer approximation (alongshore scales much longer than cross-shore ones). The results reveal non-wavelike circulations, with or without bottom friction, on a shelf of finite or unlimited width, unaffected by changing offshore boundary conditions. In the …

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Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff Jan 1998

Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff

Journal of Marine Research

The nonlinear volume changes associated with diffusion and mixing of different seawater types produce significant conversions of gravitational potential energy to kinetic energy to maintain and enhance mixing processes and to limit the magnitudes of temperature gradients that can persist in the ocean. Several examples are given to illustrate these critical temperature gradients beyond which conversion exceeds local energy consumption by mixing. The vertical temperature gradients in the Gulf Stream reduce downstream from Cape Hatteras to the critical limit found in the North Atlantic thermocline. The limiting gradients are also seen in surface thermoclines and in "staircase" structures. Although the …

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Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon Jan 1998

Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon

Journal of Marine Research

The linear equations governing stratified, wind-driven flow in an ocean of arbitrary shape may be combined into a single "advection-diffusion" equation for the pressure , in which the "flow" advecting  includes a delta-function contribution at the ocean bottom in the sense of southward "advection" of  along western continental slopes. This interpretation of the -equation helps to explain numerical solutions obtained with a finite-element model incorporating realistic North Atlantic bathymetry.

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On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham Jan 1998

On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham

Journal of Marine Research

This work examines the instabilities of steady circulations driven by stationary single-gyre wind forcing in closed rectangular basins with different aspect ratios. The stratified ocean is modeled with quasi-geostrophic 1.5-layer (equivalent-barotropic) and two-layer models. As friction is reduced, a stability threshold is encountered. In the vicinity of this threshold, unstable steady states and their unstable eigenmodes are determined. The structures of the eigenmodes and their associated energy conversion terms allow us to characterize the instabilities. In each case, the loss of stability is associated with an oscillatory instability. Several different instability mechanisms are observed. Which of these is responsible for …

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Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins Jan 1998

Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins

Journal of Marine Research

A compilation of fifteen years of tritium and 3He measurements is used to examine the ventilation of the eastern North Atlantic subtropical gyre with specific emphasis on the temporal character of the tracer age field. A multivariate regression analysis in the form of a spatiotemporal Taylor expansion is applied to observations interpolated onto isopycnal surfaces. The time-dependent component of the tracer age field is found to be statistically significant, explaining approximately 10% of the variance of the tracer age observations in the upper thermocline (σ = 26.5) and increasing to roughly 50% of the variance in the lower thermocline …

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Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley Jan 1998

Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley

Journal of Marine Research

Tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank are examined using a two-dimensional primitive equation ocean model with Mellor and Yamada (level 2.5) turbulent closure. Driven by the surface M2 tide, the model results show that tidal mixing exhibits temporal and spatial asymmetries on southern and northern flanks of the bank. It is strongest near the bottom around maximum on-bank tidal flow as a result of gravitational instability when denser water is advected upslope over lighter water. A sharp thermal depression occurs on the steep northern flank, which produces large current shear …

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Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub Jan 1998

Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub

Journal of Marine Research

Insensitivity to turbulent closure in the wind-driven nonlinear Stommel-Munk model is addressed theoretically and numerically. The QG energy equation is used to show that, with the assumption that the maximum velocities occur at inertial length scales or smaller, a Sverdrup interior is consistent with the small Rossby number assumption only when the frictional parameters exceed critical values. For frictional parameters smaller than these values, valid solutions must decrease the energy source. This is possible for non-Sverdrup solutions since the energy source is dependent on the solution. The steady-state behavior of the model was investigated via a pseudo-arclength continuation algorithm. Dependence …

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Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins Jan 1998

Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins

Journal of Marine Research

In two experiments, larval settlement was studied within a series of pipes, each containing steady, turbulent, flowing seawater. The study was designed to determine effects of flow (speed, turbulence intensity and wall shear stress) and surface orientation on rates of settlement of larvae of various taxa, and to relate variability in patterns of settlement among orientations and flows to the concomitant variability expected in rates of larval supply or delivery to the pipe walls. Patterns of settlement of all five taxa (the barnacle Balanus spp., the mussel Mytilus trossulus, the serpulid polychaete Pseudochitinopoma occidentalis, the cyclostome bryozoan Tubulipora sp., …

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Narrow Hybrid Zone Between Two Subspecies Of Big Sagebrush (Artemisia Tridentata: Aeteraceae). V. Soil Properties, Han Wang, David W. Byrd, Jeffrey L. Howard, E. Durant Mcarthur, John H. Graham, D. Carl Freeman Jan 1998

Narrow Hybrid Zone Between Two Subspecies Of Big Sagebrush (Artemisia Tridentata: Aeteraceae). V. Soil Properties, Han Wang, David W. Byrd, Jeffrey L. Howard, E. Durant Mcarthur, John H. Graham, D. Carl Freeman

Environmental Science and Geology Faculty Research Publications

We studied soils of the big sagebrush (Artemisia tridentata) hybrid zone at two locations in Utah. The elemental composition, depth, and pH of soil in the basin and mountain big sagebrush habitats differed significantly from each other and from the hybrid zone soil. The hybrid zone soil is not just a simple blend of the two parental habitat soils. Rather, it possesses novel characteristics found in neither parental habitat and is more variable than the parental habitat soils. Correspondence analyses show that the sites occupied by each parental taxon are chemically distinct. Moreover, the principal axes from the two study …

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Utilization Of Hands-On Activities In The Science Of Classroom: An Assessment Of Student Performance, Nels H. Troelstrup Jr., Dennis Clark Jan 1998

Utilization Of Hands-On Activities In The Science Of Classroom: An Assessment Of Student Performance, Nels H. Troelstrup Jr., Dennis Clark

Oak Lake Field Station Research Publications

The objectives of this project were to (1) develop and provide hands-on environmental science activities for use in middle and high school science classrooms and (2) assess changes in student performance following instruction with hands-on activities. Math and science educators from 21 classrooms across South Dakota participated in the Environmental Classroom project during the 1996 and 1997 school years. Participants were provided a workbook and instruction during twothree day workshops at the Oak Lake Field Station. In addition, participants developed a standardized student assessment tool to evaluate student performance. This assessment tool consisted of 10 multiple choice questions for each …

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1998-99 Jackrabbit Women's Basketball Media Guide, South Dakota State University Jan 1998

1998-99 Jackrabbit Women's Basketball Media Guide, South Dakota State University

Jackrabbit Women's Basketball Media Guides (1998-2014)

This is the South Dakota State University Women's Basketball Media Guide for the 1998-99 Season.

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Arboretum Annual Report, 1998, Connecticut College Jan 1998

Arboretum Annual Report, 1998, Connecticut College

Annual Reports

No abstract provided.

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Fort Wayne Alumnus, Taylor University Fort Wayne Jan 1998

Fort Wayne Alumnus, Taylor University Fort Wayne

TUFW Alumni Publications (All)

The Winter/Spring 1998 edition of The Fort Wayne Alumnus, published by Taylor University Fort Wayne in Fort Wayne, Indiana.

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Taylor: A Magazine For Taylor University Alumni And Friends (Winter 1998), Taylor University Jan 1998

Taylor: A Magazine For Taylor University Alumni And Friends (Winter 1998), Taylor University

The Taylor Magazine (1963-Present)

The Winter 1998 edition of Taylor Magazine, published by Taylor University in Upland, Indiana.

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Both Edges Of The Margin: Blacks And Asians In Mississippi Masala, Barriers To Coalition Building, Taunya Lovell Banks Jan 1998

Both Edges Of The Margin: Blacks And Asians In Mississippi Masala, Barriers To Coalition Building, Taunya Lovell Banks

Faculty Scholarship

Asians often take a middle position between White privilege and Black subordination and therefore participate in what Professor Banks calls "simultaneous racism," where one racially subordinated group subordinates another. She observes that the experience of Asian Indian immigrants in Mira Nair's film parallels a much earlier Chinese immigrant experience in Mississippi, indicating a pattern of how the dominant power uses law to enforce insularity among and thereby control different groups in a pluralistic society. However, Banks argues that the mere existence of such legal constraints does not excuse the behavior of White appeasement or group insularity among both Asians and …

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The Impact Of Foreign Investment On Indigenous Culture: An Intellectual Property Perspective, Doris Estelle Long Jan 1998

The Impact Of Foreign Investment On Indigenous Culture: An Intellectual Property Perspective, Doris Estelle Long

North Carolina Journal of International Law

No abstract provided.

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Dordt College 1998-99 Catalog, Dordt College. Registrar's Office Jan 1998

Dordt College 1998-99 Catalog, Dordt College. Registrar's Office

Academic Catalogs

Academic Catalog for 1998-99

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