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.
Helicopter launching of surface and sea‐bed drifters
The semi-enclosed nature of Long Island Sound makes it ideal for surface and sea-bed drifter studies. A U.S. Coast Guard H-3 helicopter provided a “synoptic” launch within a half tidal cycle. Drifter releases were conducted on 18 June 1973 at a total of 50 stations in Long Island and Block Island Sounds. Drops were made at various altitudes and speeds in order to determine optimum release conditions.
Jet type model for the three‐dimensional thermal plume in a crosscurrent and under wind
A dynamic three-dimensional model for predicting water temperatures in a thermal plume has been formulated and tested. The plume that results from the discharge of heated water is described in terms of a buoyant, turbulent half jet. The effects of a crosscurrent and wind can be accommodated by the model. Mixing by turbulence, lateral spread due to buoyancy, heat transfer at the water surface, and deflection of the main trajectory under wind shear stress in a current are accounted for. Although it was necessary to make several broad assumptions, e.g., that all cross-sectional temperature distributions are similar and that there is no distortion of the cross section by wind, the results show the overall behavior of the plume reasonably well. The model does not account for the effects of solid boundaries; its main features are its simplicity and comprehensiveness, its combination of the several processes having a major effect on plume behavior, and its ability to include possible future experimental or theoretical results without major changes in the program.