6,947 research outputs found

    Estuarine turbidity, flushing, salinity, and circulation

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    The effects of estuarine turbidity, flushing, salinity, and circulation on the ecology of the Chesapeake Bay are discussed. The sources of fresh water, the variations in salinity, and the circulation patterns created by temperature and salinity changes are analyzed. The application of remote sensors for long term observation of water temperatures is described. The sources of sediment and the biological effects resulting from increased sediments and siltation are identified

    The dynamic structure of a coastal plain estuary

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    The time mean equations of motion applicable to a coa.stal plain estuary are developed and discussed. Time series observations of temperature, salinity, and current velocity from two sections in the James River are utilized to obtain the mean lateral and longitudinal components of the relative pressure field, the Coriolis force, and the field accelerations...

    A study of the salt balance in a coastal plain estuary

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    Observations of salinity and current velocity taken in the James River estuary are used in this investigation. Time means are taken over several tidal cycles and the nonadvective motions and nonadvective salt flux are related to these means. The analysis shows that in the James River estuary the horizontal advective flux and the vertical nonadvective flux of salt are the most important factors in maintaining the salt balance. The vertical advective flux is of secondary importance but is still significant. The horizontal nonadvective flux of salt is small. In addition, the vertical nonadvective flux of salt is partly related to the magnitude of the oscillatory tidal currents

    Salinity distribution and circulation in the Chesapeake Bay estuarine system

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    The salinity distribution in a coastal plain estuary governs the dynamic structure. In the estuaries studied, the salinity increases with depth, the salinity-depth curve having the general shape of an inverse tangent function. Though there is a layer of relatively rapid increase in salt content with depth, separating an upper less saline layer from a lower more saline layer, this halocline is still sufficiently weak to allow a downward random flux of fresh water as well as an upward random flux of salt. The longitudinal salinity gradient is approximately uniform with depth. The salinity is on the average higher on the right side of the estuary (looking downstream) than on the left...

    Physical oceanographic investigations in the Eastern Bering and Chukchi Seas during the summer of 1947

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    New information on the physical properties of the waters in the eastern Bering and Chukchi seas is discussed. It shows that, in summer, the water masses of this area are complicated by the circulation and advective processes. In general, the southern Bering Sea water flows northward and is modified by warm low-salinity water from rivers along the Alaskan coast and from intrusions of cold high-salinity water from the western Bering Sea. This mixture of water funn els through the Bering Strait principally at the surface on the eastern side...

    A method for determining mean longitudinal velocities in a coastal plain estuary

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    It is shown that the longitudinal component of the mean velocity in a coastal plain estuary may be computed by indirect methods. To do this, use is made of the lateral and longitudinal components of the equation of motion, the tidal velocity amplitudes, and a deduced relationship between the vertical and lateral eddy stresses. The method is evaluated for a station in the James River estuary. The resultant computed velocities agree quantitatively with the corresponding observed velocities

    A test of mixing length theories in a coastal plain estuary

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    Observations of vertical and horizontal variations in salinity and velocity in the James River estuary have been previously employed in the indirect determination of the vertical eddy flux of salt

    An inexpensive and rapid technique for obtaining current profiles in estuarine waters

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    A current indicator, consisting of a confined submerged biplane-shaped drag and a device for reading the angle made by the suspending wire with t he vertical, is introduced in t heory and practice. It was designed for rapid determination of current velocities and directions at any depth from a vessel an chored in shallow water. A number of calibration runs made with t he Drag and with a von Arx Current Meter indicate that the Drag is reliable and suffi ciently accurate for the purpose for wluch it was designed. The gear proved to be rugged, easy to use, and inexpensive. It requires little time to make a number of observations from the surface down to 50 feet

    Optical Weak Link between Two Spatially Separate Bose-Einstein Condensates

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    Two spatially separate Bose-Einstein condensates were prepared in an optical double-well potential. A bidirectional coupling between the two condensates was established by two pairs of Bragg beams which continuously outcoupled atoms in opposite directions. The atomic currents induced by the optical coupling depend on the relative phase of the two condensates and on an additional controllable coupling phase. This was observed through symmetric and antisymmetric correlations between the two outcoupled atom fluxes. A Josephson optical coupling of two condensates in a ring geometry is proposed. The continuous outcoupling method was used to monitor slow relative motions of two elongated condensates and characterize the trapping potential.Comment: 4 pages, 5 figure
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