The Effects of Climatological and Transient Wind Forcing on Eddy Generation in the California Current System
The Effects of Climatological and Transient Wind Forcing on Eddy Generation in the California Current System

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Publisher:

Published: 1989

Total Pages: 0

ISBN-13:

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A high-resolution, multi-level, primitive equation ocean model is used to examine the response to transient and climatological wind forcing of an idealized, flat-bottomed oceanic regime on a beta-plane, along an eastern boundary. An annually periodic wind forcing function with zonal variability is used as transient forcing in several experiments using both winter and summer initializations. When the curl component of the forcing is stronger than the stress, as in the wintertime, a surface poleward flow develops in the nearshore region with an equatorward flow offshore. When wind stress dominates the forcing, as in the summertime, a coastal jet develops with an undercurrent. In other experiments, spatially varying one degree and two tenths degree steady wind stress data are used as climatological forcing. The one degree climatological wind stress data has positive curl at the coast which causes a poleward surface flow to develop. When two tenths degree wind stress data is used in the nearshore area, both positive and negative curl in the coastal region result in the formation of poleward and equatorward currents, respectively. As a result of convergence in the surface flow, eddies and a well defined cold filament develop. These results show that the interaction of diverse coastal currents driven by an equally diverse wind field can play an important role in the production of cold filaments and eddies. Theses. (jhd).

The Effects of Climatological and Transient Wind Forcing on Eddy Generation in the California Current System
The Effects of Climatological and Transient Wind Forcing on Eddy Generation in the California Current System

Author: Robert W. Edson

Publisher:

Published: 1989

Total Pages: 154

ISBN-13:

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A high-resolution, multi-level, primitive equation ocean model is used to examine the response to transient and climatological wind forcing of an idealized, flat-bottomed oceanic regime on a beta-plane, along an eastern boundary. An annually periodic wind forcing function with zonal variability is used as transient forcing in several experiments using both winter and summer initializations. When the curl component of the forcing is stronger than the stress, as in the wintertime, a surface poleward flow develops in the nearshore region with an equatorward flow offshore. When wind stress dominates the forcing, as in the summertime, a coastal jet develops with an undercurrent. In other experiments, spatially varying one degree and two tenths degree steady wind stress data are used as climatological forcing. The one degree climatological wind stress data has positive curl at the coast which causes a poleward surface flow to develop. When two tenths degree wind stress data is used in the nearshore area, both positive and negative curl in the coastal region result in the formation of poleward and equatorward currents, respectively. As a result of convergence in the surface flow, eddies and a well defined cold filament develop. These results show that the interaction of diverse coastal currents driven by an equally diverse wind field can play an important role in the production of cold filaments and eddies. Theses. (jhd).

A Numerical Study of Seasonal Wind Forcing Effects on the California Current System
A Numerical Study of Seasonal Wind Forcing Effects on the California Current System

Author: Ross P. Mitchell

Publisher:

Published: 1993

Total Pages: 136

ISBN-13:

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A high-resolution, multi-level, primitive equation ocean model is used to examine the response of an idealized, flat-bottomed, eastern boundary oceanic regime on a beta-plane to both steady and seasonally-varying climatological wind forcing. The focus of the study is the California Current System along the coastal region, from 35 deg N to 45 deg N, off the Western United States. With steady equatorward wind forcing, a surface equatorward current and poleward undercurrent develop. Eddies form around days 60 and 7 with initial development in the northern region of the domain. The strong meandering current continues to grow throughout the 360 days of model time and can produce eddies that have wavelengths up to 200 km and can propagate at least -200 km offshore. When the alongshore component of the temporally averaged seasonally varying climatological wind forcing is used, there is a weak poleward undercurrent and equatorward surface current. There is weak upwelling and very little eddy activity with the eddies only propagating to -100 km offshore. When alongshore component of the time-dependent wind forcing with spatial variability in latitude is used, a surface equatorward jet, poleward undercurrent and eddies are generated. The eddies form throughout the domain in this experiment due to a competition between the 0-plan effect and the continuous and stronger equatorward wind forcing in the southern portion of the domain. The eddies in this experiment propagate at least -150 km from shore.

Wind Forcing of Eddies and Jets in the California Current System
Wind Forcing of Eddies and Jets in the California Current System

Author: Terrance A. Tielking

Publisher:

Published: 1988

Total Pages: 118

ISBN-13:

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A high-resolution, multi-level, primitive equation ocean model is used to examine the response to wind forcing of an idealized flatbottomed oceanic regime along an eastern ocean boundary. A band of steady winds, either with or without a curl, is used as forcing on both an f-plane and a beta-plane. In addition, a stability analysis is made to determine if the necessary and sufficient conditions for instability processes to occur are satisfied. It is seen that when the wind driven coastal jet and undercurrent are unstable (which occurs in the cases of wind with no curl), eddies and jets are generated. In the case of wind with curl, since the Davidson Current develops rather than the coastal jet and undercurrent, no eddies develop. A comparison of model results with available observations shows that both the time-averaged and instantaneous model simulations of the coastal jet, undercurrent and eddies are consistent with available observational data. Study results support the hypothesis that wind forcing can be an important eddy generation mechanism for the California Current System. (edc).

Analysis of Eddy Resolving Model of the California Current System
Analysis of Eddy Resolving Model of the California Current System

Author: Nicholas J. Cipriano

Publisher:

Published: 1998

Total Pages: 96

ISBN-13:

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A high-resolution, multi-level, primitive equation ocean model is used to investigate the combined role of seasonal wind forcing, thermohaline gradients, and coastline irregularities on the formation of currents, meanders, eddies, and filaments in the California Current System from 22.5 deg N to 47.5 deg N. An investigation of the dynamical reasons for the generation and growth of meanders and eddies is conducted along with a sensitivity study to investigate the formation of the Davidson Current. Model results are consistent with the generation of eddies from instabilities of the equatorward current and poleward undercurrent via barotropic and baroclinic instability processes. The meandering equatorward jet south of Cape Blanco is shown to be a continuous feature, which divides coastally-influenced water from water of offshore origin. The area off southern Baja is shown to be a highly dynamic environment for meanders, filaments, and eddies, while the area off Point Eugenia is shown to be a persistent cyclonic eddy generation region. Both the Southern California Countercurrent rounding Point Conception and the shoaling of the poleward undercurrent are shown to play important roles in generating the Davidson Current in the fall.

Analysis of Eddy Resolving Model of the California Current System
Analysis of Eddy Resolving Model of the California Current System

Author: Nicholas J. Cipriano

Publisher:

Published: 1998-09-01

Total Pages: 115

ISBN-13: 9781423556053

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A high-resolution, multi-level, primitive equation ocean model is used to investigate the combined role of seasonal wind forcing, thermohaline gradients, and coastline irregularities on the formation of currents, meanders, eddies, and filaments in the California Current System from 22.5 deg N to 47.5 deg N. An investigation of the dynamical reasons for the generation and growth of meanders and eddies is conducted along with a sensitivity study to investigate the formation of the Davidson Current. Model results are consistent with the generation of eddies from instabilities of the equatorward current and poleward undercurrent via barotropic and baroclinic instability processes. The meandering equatorward jet south of Cape Blanco is shown to be a continuous feature, which divides coastally-influenced water from water of offshore origin. The area off southern Baja is shown to be a highly dynamic environment for meanders, filaments, and eddies, while the area off Point Eugenia is shown to be a persistent cyclonic eddy generation region. Both the Southern California Countercurrent rounding Point Conception and the shoaling of the poleward undercurrent are shown to play important roles in generating the Davidson Current in the fall.

Masters Theses in the Pure and Applied Sciences
Masters Theses in the Pure and Applied Sciences

Author: W. H. Shafer

Publisher: Plenum Publishing Corporation

Published: 1992

Total Pages: 392

ISBN-13: 9780306443480

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Masters Theses Listed by Discipline: Aerospace Engineering. Agricultural Economics, Sciences and Engineering. Architechtural Engineering and Urban Planning. Astronomy. Astrophysics. Ceramic Engineering. Communications Engineering and Computer Science. Cryogenic Engineering. Electrical Engineering. Engineering Mechanics. Engineering Physics. Engineering Science. Fuels, Combustion, and Air Pollution. General and Environmental Engineering. Geochemistry and Soil Science. Geological Sciences and Geophysical Engineering. Geology and Earth Science. Geophysics. Industrial Engineering. Marine and Ocean Engineering. Materials Science and Engineering. Mechanical Engineering and Bioengineering. Metallurgy. Meteorology and Atmospheric Science. 17 additional disciplines. Index.

A Large-Scale Modeling Study of the California Current System
A Large-Scale Modeling Study of the California Current System

Author: James T. Monroe

Publisher:

Published: 1997-12-01

Total Pages: 148

ISBN-13: 9781423563853

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A high resolution, multi-level, primitive equation ocean model is used to investigate the combined role of wind forcing, thermohaline gradients, and coastline irregularities on the formation of currents, meanders, eddies, and filaments in the California Current System (CCS) from 22.5 deg N to 47.5 deg N. An additional objective is to further characterize the formation of the Davidson Current, seasonal variability off Baja California, and the meandering jet south of Cape Blanco. The model includes a realistic coastline and is forced from rest using climatological winds, temperatures, and salinities. The migration pattern of the North Pacific Subtropical High plays a significant role in the generation and evolution of CCS structures. In particular, variations in wind stress induce flow instabilities which are enhanced by coastline perturbations. An inshore train of cyclonic eddies, combined with a poleward undercurrent of varying seasonal depths, forms a discontinuous countercurrent called the Davidson Current north of Point Conception. Off Baja, the equator-ward surface jet strengthens (weakens) during spring and summer (fall and winter). Model results also substantiate Point Eugenia as a persistent cyclonic eddy generation area. The model equator-ward jet south of Cape Blanco is a relatively continuous feature, meandering offshore and onshore, and divides coastally influenced water from water of offshore origin.