Analysis and interpretation of tidal currents in the coastal boundary layer

May, Paul

doi:10.1575/1912/3083

Cited by 16 publications

(12 citation statements)

References 42 publications

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“…However, it may also be~as concluded by May (1979), that the internal motions make a relatively greater contribution to the cross-shore modes since the barotropic motions are strongly polarized in the alongshore direction. Flagg (1977), and Mayer et al (1980), have shown inertial kinetic energy to decay rapidly in the shoreward direction thereby limiting significant levels to middle and outer shelf locations.…”

Section: Pe Rio D (H Rs )mentioning

confidence: 92%

“…Tidal analyses undertaken by May (1979) led to confirmation of this number via a somewhat different approach. Using current measurements from the COBalT experiment, the vertical structure of tidal currents was compared to the predictions of a turbulent wall layer model.…”

Section: !mentioning

confidence: 99%

“…The most enticing course of action, and perhaps the greatest leap of faith as well, is the wholesale transference of the Coastal Boundary Layer concept with all its lore directly to nearshore oceanic environments. Any such application is bound to be complicated by the additional influences of vigorous tidal fluctuations (May, 1979) as well as interaction with larger scale flow features of the continental shelf and perhaps even the general circulation of the deep ocean. In any event the physical factors which served to differentiate the CBL from interior regions in the Great Lakes will also be operative and apply powerful dynamical constraints on motions in the oceanic boundary layer as well.…”

Section: The Concept Of the Coastal Boundary Layermentioning

confidence: 99%

“…CUE 1, CUE2) the CO BOLT experiment is the first study specifically designed with sufficient resolution to investigate the temporal and spatial complexities of the oceanic nearshore band. The project, which represents a six year (1974)(1975)(1976)(1977)(1978)(1979) Sound which is known to have a major influence upon the tidal currents (Swanson, 1976;May, 1979), the local hydrography (Ketchum and Corwin, 1964), and may perhaps affect wind-driven currents as well. The close proximity of the Shinnecock Inlet may also have some effect upon the study area, although through the analysis of airborne radiation thermometric data, Powell and SethuRaman (1979) have concluded that any influence of the inlet upon scalar variables within the COBalT region is quite minor.…”

Section: Cobolt Deployments and Experimental Configurationsmentioning

confidence: 99%

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The dynamics and kinematics of the coastal boundary layer off Long Island

Pettigrew¹

1980

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Data from the COBOLT experiment, which investigated the first 12 km off Long Island's south shore, are analyzed and discussed. Moored current meter records indicate that the nearshore flow field is strongly polarized in the alongshore direction and its fluctuations are well correlated with local meteorological forcing. Complex empirical orthogonal function analysis suggests that subtidal velocity fluctuations are barotropic in nature and are strongly influenced by bottom friction.Wind-related inertial currents were observed within the coastal boundary layer (CBL) under favorable meteorolgical and hydrographical conditions. The magnitude of these oscillations increases with distance from shore, and they display a very clear 180 0 phase difference between surface and bottom layers. Nearshore inertial oscillations of both velocity and salinity records appear to lead those further s€award, suggesting local generation and subsequent radiation away from the coast.The response of the coastal zone to impulsive wind forcing is discussed using simple slab and two-layer models, and the behavior of the nearshore current field examined. The major features of the observed inertial motions are in good qualitative agreement with model predictions. It is found that, in a homogeneous domain, the coastal boundary condition effectively prohibits inertial currents over the entire coastal zone. In the presence of stratification the offshore extent of this prohibition is greatly reduced and significant inertial currents may OCcur within one or two internal deformation radii of the coast. The "coastal effect", in the form of surface and interfacial waves which propagate -3-away from the coast, modifies the "pure" i nerti al response as it would exist far from shore. The kinematics of this process is such that a 180· phase difference between currents in the two layers is characteristic of the entire coastal zone even before the internal wave has had time to traverse the CBL. It is also suggested that, for positions seaward of several internal deformation radii, interference between the surface and internal components of the coastal response will cause maximum inertial amplitudes to occur for t > x/c2, where c2 is the phase speed of the internal disturbance.The hydrographic structure of the CBL is observed to undergo freQuent homogenization. These events are related to both advective and mixing processes. Horizontal and vertical exchange coefficients are estimated from the data, and subsequently used in a diffusive model which accurately reproduces the observed mean density distribution in the nearshore zone.Dynamic balance calculations are performed which indicate that the subtidal cross-shore momentum balance is very nearly geostrophic. The calculations also suggest that the longshore balance may be reasonably represented by a steady, linear equation of motion which includes surface and bottom stresses.Evidence is presented which shows that variations in the longshore wind-stress component are primarily responsible for the ener...

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Section: Pe Rio D (H Rs )mentioning

confidence: 92%

Section: !mentioning

confidence: 99%

Section: The Concept Of the Coastal Boundary Layermentioning

confidence: 99%

Section: Cobolt Deployments and Experimental Configurationsmentioning

confidence: 99%

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The dynamics and kinematics of the coastal boundary layer off Long Island

Pettigrew¹

1980

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“…Most of these involved deployment of a mooring array from which temperature, salinity, and water velocity were measured; hydrographic surveys, which measured the above quantities at closely spaced stations, were performed almost daily during all studies. Instrumentation and measurement techniques are detailed elsewhere (May 1979;Pettigrew 198 1). The site of the COBOLT measurements and a typical arrangement of the moorings and flag stations are shown in Figs.…”

Section: Introductionmentioning

confidence: 99%

Intrusions of outer shelf and slope water within the nearshore zone off Long Island, New York1,2

Churchill

1985

Limnology & Oceanography

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From 1974 through 1978 studies were made of temperature, salinity, and water velocity, by hydrographic surveys and from moored instruments, in the waters within 15 km of the southern Long Island coastline. Data of late summer reveal frequent intrusions of anomalous water which appear to be of slope or outer shelf origin. Three intrusions of notably differing character are described. Two occurred at middepth, within the pycnocline. Concurrent hydrographic and current meter data suggest that these water masses were transported shoreward due to circulation forced by wind stress and by longshore density gradients. The third intrusion was initially observed near the surface and was of anomalously high temperature. Its T/S relation was similar to a warm and salty bolus detected 12 days earlier in the midshelf region. Hydrographic data suggest that this bolus may have been a detached parcel of slope water. Such intrusions may commonly occur during summer and fall and may be related to the appearance of tropical fish in the Long Island -vicinity during these seasons.

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Vertical structure of the tidal current ellipse in a rotating basin

Yasuda¹

1987

Journal of the Oceanographical Society of Japan

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Analysis and interpretation of tidal currents in the coastal boundary layer

Cited by 16 publications

References 42 publications

The dynamics and kinematics of the coastal boundary layer off Long Island

The dynamics and kinematics of the coastal boundary layer off Long Island

Intrusions of outer shelf and slope water within the nearshore zone off Long Island, New York1,2

Vertical structure of the tidal current ellipse in a rotating basin

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