Modeling Studies of Wind and Thermohaline Forcing on the California Current System

Modeling Studies of Wind and Thermohaline Forcing on the California Current System PDF Author: Philip W. Vance
Publisher:
ISBN: 9781423569930
Category :
Languages : en
Pages : 89

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Book Description
A high-resolution, multi-level, primitive equation model is initialized with climatological data to study the combined effects of wind and thermohaline forcing on the ocean circulation of the California Current System (CCS). The ocean circulation is generated by the model using a combination of climatological wind stress and thermohaline forcing. In the first experiment, the effects of thermohaline forcing alone are evaluated, in the second experiment, previously conducted, the effects of wind forcing are isolated, while in the third experiment, the combined effects of wind and thermohaline forcing are looked at. The results from the combined experiment show that even though the effects of wind forcing dominate the CCS, the additional effects of the thermohaline forcing results in the following: the seasonal development of a poleward surface current and an equatorward undercurrent in the poleward end of the model region; an onshore geostrophic component, which results in a temperature front and stronger surface and subsurface currents between Cape Mendocino and Point Arena; and a region of maximum eddy kinetic energy inshore of tilde 125 deg W between Cape Mendocino and Point Arena, associated with the temperature front. These model simulations are qualitatively similar to recent hydrographic, altimetric, drifter, and moored observations of the CCS.

Modeling Studies of Wind and Thermohaline Forcing on the California Current System

Modeling Studies of Wind and Thermohaline Forcing on the California Current System PDF Author: Philip W. Vance
Publisher:
ISBN: 9781423569930
Category :
Languages : en
Pages : 89

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Book Description
A high-resolution, multi-level, primitive equation model is initialized with climatological data to study the combined effects of wind and thermohaline forcing on the ocean circulation of the California Current System (CCS). The ocean circulation is generated by the model using a combination of climatological wind stress and thermohaline forcing. In the first experiment, the effects of thermohaline forcing alone are evaluated, in the second experiment, previously conducted, the effects of wind forcing are isolated, while in the third experiment, the combined effects of wind and thermohaline forcing are looked at. The results from the combined experiment show that even though the effects of wind forcing dominate the CCS, the additional effects of the thermohaline forcing results in the following: the seasonal development of a poleward surface current and an equatorward undercurrent in the poleward end of the model region; an onshore geostrophic component, which results in a temperature front and stronger surface and subsurface currents between Cape Mendocino and Point Arena; and a region of maximum eddy kinetic energy inshore of tilde 125 deg W between Cape Mendocino and Point Arena, associated with the temperature front. These model simulations are qualitatively similar to recent hydrographic, altimetric, drifter, and moored observations of the CCS.

A Large-Scale Modeling Study of the California Current System

A Large-Scale Modeling Study of the California Current System PDF Author: James T. Monroe
Publisher:
ISBN: 9781423563853
Category :
Languages : en
Pages : 148

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Book Description
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.

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 PDF Author: Ross P. Mitchell
Publisher:
ISBN:
Category : California Current
Languages : en
Pages : 136

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Book Description
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.

Analysis of Eddy Resolving Model of the California Current System

Analysis of Eddy Resolving Model of the California Current System PDF Author: Nicholas J. Cipriano
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
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 PDF Author: Nicholas J. Cipriano
Publisher:
ISBN: 9781423556053
Category :
Languages : en
Pages : 115

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Book Description
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.

Wind Forcing of Eddies and Jets in the California Current System

Wind Forcing of Eddies and Jets in the California Current System PDF Author: Terrance A. Tielking
Publisher:
ISBN:
Category : Ocean currents
Languages : en
Pages : 0

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Book Description
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).

A Wind-forced Modeling Study of the Canary Current System from 30° N to 42.5° N

A Wind-forced Modeling Study of the Canary Current System from 30° N to 42.5° N PDF Author: Daniel W. Bryan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
A high-resolution, multi-level, primitive equation ocean model is used to investigate the roles of wind forcing and irregular coastline geometry in the generation of currents, eddies, jets and filaments in the Canary Current System (CCS) from 30 to 42.5 deg N. To study the generation, evolution, and sustainment of the currents, eddies, jets and filaments in the CCS, the model is forced from rest using seasonal climatological winds and a realistic coastline. Results of the experiment show that wind forcing alone is capable of generating surface currents, undercurrents, meanders, eddies, and filaments. Preferred eddy generation locations, enhanced growth of meanders, eddies, and filaments are seen. The features produced by the model are consistent with available observations of the CCS.

Dynamics of the Southern California Current System

Dynamics of the Southern California Current System PDF Author: Emanuele Di Lorenzo
Publisher:
ISBN:
Category :
Languages : en
Pages : 254

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Book Description


A Wind-Forced Modeling Study of the Canary Current System from 30 Degrees N to 42. 5 Degrees N

A Wind-Forced Modeling Study of the Canary Current System from 30 Degrees N to 42. 5 Degrees N PDF Author: Daniel Bryan
Publisher:
ISBN: 9781423559399
Category :
Languages : en
Pages : 96

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Book Description
A high-resolution, multi-level, primitive equation ocean model is used to investigate the roles of wind forcing and irregular coastline geometry in the generation of currents, eddies, jets and filaments in the Canary Current System (CCS) from 30 to 42.5 deg N. To study the generation, evolution, and sustainment of the currents, eddies, jets and filaments in the CCS, the model is forced from rest using seasonal climatological winds and a realistic coastline. Results of the experiment show that wind forcing alone is capable of generating surface currents, undercurrents, meanders, eddies, and filaments. Preferred eddy generation locations, enhanced growth of meanders, eddies, and filaments are seen. The features produced by the model are consistent with available observations of the CCS.

Investigations of the California Current System

Investigations of the California Current System PDF Author: William James Crawford
Publisher:
ISBN: 9780355333701
Category :
Languages : en
Pages : 251

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Book Description
The California Current System (CCS) is undoubtedly one of the most well studied regions of the world ocean. The seasonal variability of equatorward upwelling winds allow for the development of a complex set of dynamical features while also sustaining a rich diversity of marine organisms. With use of the state-of-the-art Regional Ocean Modeling System (ROMS) 4-dimensional variational (4D-Var) data assimilation system, the circulation of the CCS is explored in varying capacities over the time period 1980-2010.