Tidal stream

Freese, K., Gondolo, P, Newberg, H., Lewis, M. 2003. The Effects of the Sagittarius Dwarf Tidal Stream on Dark Matter Detectors, Phys. Rev. Lett., to appear [Preprint astro-ph/0310334]... 

Ibata, R., Lewis, G. F., Irwin, M., Totten, E., Quinn, T. 2001. Great Circle Tidal Streams Evidence for a Nearly Spherical Massive Dark Halo around the Milky Way, ApJ551, 294... 

Bianchi (2001) further supported that lignin was not degraded efficiently under low-oxygen conditions in a tidal stream, adjacent to Lake Pontchartrain estuary (USA). 

Engelhaupt, E., and Bianchi, T.S. (2001) Sources and composition of high-molecular-weight dissolved organic carbon in a southern Louisiana tidal stream (Bayou Trepagnier). Lirnnol. Oceanogr. 46, 917-926. 

The northern part of the area with low tidal flows (u < 0.5 m/s) stratifies in the summer, but the area adjacent to the French coast remains mixed throughout the year due to the high tidal stream velocities (>2 m/s) (23). 

A more benign approach is to extract energy from the tidal flows that occur between headlands and islands or in and out of estuaries. The power available in these tidal streams varies with the cube of the current velocity and while sea currents are typically around 3 m/sec, much lower than the minimum velocities required for wind turbines ( 7m/sec), the density of seawater is such that the output of tidal stream devices is much higher than equivalently sized wind generators. The energy flows are significant with aroimd 7.5 GW of accessible resource in Scotland alone. ... 

Stok, J. P. van der, 1897. Wind and weather, currents, tides and tidal streams in the east Indian Archipelago. Batavia, 208 p. 

Table II. Principal Harmonic Constants of the Tide and Tidal Stream for Long Island Sound ... 

I. If the tide height and tidal stream speeds can be represented by sinusoidal terms, Eq. (2.2) reduces to... 

An estimate of the dissipation of energy by friction in all of LIS can be made if it is assumed that the only difference in the tidal friction between the eastern and western parts of the Sound is that due to the increased speed of the tidal stream. The power used in work against friction... 

Currents in the Sound are due to the tidal stream, to the estuarine circulation, and to wind stress acting on the water surface. Systematic surveys of the currents in the Sound have been made from time to time by the U.S. National Ocean Survey. Current meters have been placed in grid-pattern arrays for time intervals sufficiently long to reveal the principal tidal constituents of the current. Data obtained this way were used by G. A. Riley (1952, 1956) to describe the estuarine circulation of the Sound. The utility of these meter records in the study of sediment transport is limited because the observations were all made during the... 

Bokuniewicz (1976) has shown that the most satisfactory two-component descriptions of the sediment in Long Island Sound is in terms of sand (particle size >70 p,m) and mud (all smaller particles). Sand is transported close to the bottom, probably as bed load most of the time, whereas mud is excited throughout the water column by tidal stream turbulence. Sand grains are not cohesive, but mud particles may adhere to each other because of electrostatic attraction or the presence of organic adhesive agents. 

It was estimated from wave data that only in a zone around the margins of the Sound where the water is less than 18 m deep are the particle velocities of waves a significant fraction of the tidal stream speed. Direct evidence of excitation of sediment by waves in this zone is found in turbidity measurements and in the structure of surficial sediment layers. For example. Fig. 11 shows a turbidity track made from deep to shallow water in an area where the bottom is mud and the tidal stream weak. There is resuspension of mud through the water column where the depth is less than about half the wavelength of the waves present at the time the track... 

The crest advanced 6.7 m in 148 days and the sand flux was 0.7 m / sec. The westward flux of sand over the Mattituck sill is due to the excitation of the sand by the tidal stream and advection by the estuarine circulation (Bokuniewicz et al., 1977). According to this model, the sand... 

Transport of mud in Long Island Sound requires, first, resuspension of pellets from the surficial layer on the bottom and then the advection and diffusion of the resuspended material. To describe the transport of suspended sediment quantitatively, the sediment concentration gradient in the vertical direction through the water column and the flux of material into (or out of) the bottom layer of unbound sediment must be known. Both quantities depend on the distribution of velocity fluctuations in the tidal stream and so, even in deep water, are sensitive to weather condi-... 

In this article a simplified mass balance has been used to describe the net transport of sand over an accreting mud bottom. The combination of these two sedimentary processes controls the transition from sand to mud on the floor of the Sound. The distribution of sand may be described with three parameters an advection velocity of sand grains, an eddy-diffusion coefficient for mobile sand, and a rate of accumulation of marine mud. (Only the ratios of these quantities are needed if the distribution is in a steady state.) The motion of sand is thereby represented with both a deterministic part and a statistical part. The net, one-way advection of sand is the result of the superposition of an estuarine circulation on the tidal stream, and unpredictable variations in the rate of sand transport are represented as an eddy-diffusion process. Sand is immobilized when it is incorporated into the permanent deposit of marine mud. 

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