Net drift in an atypical estuary, Long Island Sound
Long Island Sound is an estuary with two-layered flow at the eastern opening to the ocean and a salinity gradient of about 5 parts per thousand between the eastern and western extremes. Tidal currents, wind-driven circulation, and river inflow and fresh water influx are investigated as factors affecting the net drift. Current measurements in eastern Long Island Sound indicate that the tidal circulation features that predominate there do not normally affect the net drift at the New Haven dump site. Drifter returns and a numerical model indicate that seasonal prevailing winds seem to be the primary cause of the net drift in central Long Island Sound.
Some estimates of transport processes in Long Island Sound
A parametric description of lateral and vertical oscillatory transport in two segments of Long Island Sound is presented. The vertical eddy viscosity and diffusivity coefficients are estimated on the basis of a model for turbulent kinetic energy transfer. Characteristics of horizontal mixing are examined by means of dimensional analysis. The relative importance of the mechanisms controlling mass distribution in the estuary is evaluated by calculating longitudinal dispersion coefficients in a form introduced by Fisher (1972). It is shown that the mass transport in Long Island Sound is governed mainly by two processes: lateral turbulent dispersion and net longitudinal transport caused by the density gradients.
Tidal Currents Survey - New Field Techniques
Note on author. — Lieutenant W e s t b r o o k was graduated from Worcester Polytechnic Institute in 1953 with a B.S. in Civil Engineering, and the same year was commissioned in the U.S. Coast & Geodetic Survey. During his nine years in the C&GS, Lieutenant W e s t b r o o k has seen service aboard six ships engaged in hydrographic and tidal current surveys along the Atlantic Coast of the U.S., Alaska and Puerto Rico. Shore-duty tours include steel tower triangulation and gravimetric surveys in the interior of the U.S., and duty with the U.S. Navy as an instructor at the U.S. Naval Amphibious School, Norfolk, Virginia. Material for this article was gathered in 1959 when Lieutenant W e s t b r o o k was Executive Officer aboard the USC&GS Ship Manner. The Marmer was engaged in making an extensive tidal current survey of New York Harbor.