Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992. / Includes bibliographical references (p. 49-52). / by Marjorie Anne MacWhorter Friedrichs. / M.S.

As part of the sustainable management of the Port of Saint John there is a critical need to maintain sufficient under keel clearance for the various container and cruise ship traffic in and out of the harbour. Because of high and variable sedimentation rates, annual maintenance dredging is necessary and causes economic concerns for the Port. Therefore to better predict future dredging volumes and hence improve the budgeting process for the Port of Saint John, the estuarine circulation of the harbour has been analysed to better quantify the relative importance of the offshore sediments that contribute to the high dredging volumes in the Saint John harbour. The Port of Saint John lies at the mouth of the Saint John River on the north side of the macrotidal Bay of Fundy. Because of this, the harbour sedimentation is influenced by two major sources of siltation: the Saint John River and the Bay of Fundy. The sediment flux from the river is strongly modulated by the seasonal variations in river discharge. In the Bay of Fundy, there is significant resuspension of offshore marine sediments. To better understand this complex interaction between the fresh water flow and the tidal inflow of salt water, high density oceanographic surveys have been conducted at four different river discharge periods. In order to quantitatively analyse the mixing of the fresh and salt water in the harbour channels, high density ADCP currents and CTD measurements were acquired along main longitudinal axis of the Main Harbour channel and Courtenay Bay over four tidal cycles. By imaging the 200kHz acoustic volume backscatter within the water column, the appearance of interfacial waves at the pycnocline can be examined. The optical backscatter sensor provided observations used to estimate suspended sediment concentrations. A cross-sectional analysis of the flow at a location 700m south and seaward of the Rodney bay terminal in the Main Channel revealed that regardless of the river discharge rate, the interfacial waves are best developed on the rising tide. However, during the Spring freshet the interfacial waves are also developed at high tide, low tide and falling tide. Examination of the timing and location of the interfacial waves are important because they influence the nature of sediment transport in the Main Harbour Channel. During high river discharge periods, the sediment concentration and volume flux estimates indicate that the river is the main source of sediments. For the low river discharge periods, the observations suggest that the possible source of suspended sediments observed in the lower saline layer are either from outside of the harbour or bottom sediments being resuspended on the rising tide.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1980. / Microfiche copy available in Archives and Science. / Bibliography: leaves 77-78. / by William Kurt Dewar. / M.S.

Thesis (Ph. D.)--Joint Program in Oceanographic Engineering (Massachusetts Institute of Technology, Dept. of Civil Engineering; and the Woods Hole Oceanographic Institution), 1989. / Includes bibliographical references (leaves 140-145). / The relationship between depth-averaged velocity and bottom stress for wind-driven flow in unstratified coastal waters is examined here. The adequacy of traditional linear and quadratic drag laws is addressed by comparison with a 2 1/2-D model. A 2 1/2-D model is one in which a simplified 1-D depth-resolving model (DRM) is used to provide an estimate of the relationship between the flow and bottom stress at each grid point of a depth-averaged model (DAM). Bottom stress information is passed from the DRM to the DAM in the form of drag tensor with two components: one which scales the flow and one which rotates it. This eliminates the problem of traditional drag laws requiring the flow and bottom stress to be collinear. In addition, the drag tensor field is updated periodically so that the relationship between the velocity and bottom stress can be time-dependent. However, simplifications in the 2 1/2-D model that render it computationally efficient also impose restrictions on the time-scale of resolvable processes. Basically, they must be much longer than the vertical diffusion time scale. Four progressively more complicated scenarios are investigated. The important factors governing the importance of bottom friction in each are found to be 1) non-dimensional surface Ekman depth ... is the surface shear velocity, f is the Coriolis parameter and h is the water depth 2) the non-dimensional bottom roughness, zo/h where zo is the roughness length and 3) the angle between the wind stress and the shoreline. Each has significant influence on the drag law. The drag tensor magnitude, r, and the drag tensor angle, 0 are functions of all three, while a drag tensor which scales with the square of the depth-averaged velocity has a magnitude, Cd, that only depends on zo/h. The choice of drag law is found to significantly affect the response of a domain. Spin up times and phase relationships vary between models. In general, the 2 1/2-D model responds more quickly than either a constant r or constant Cd model. Steady-state responses are also affected. The two most significant results are that failure to account for 0 in the drag law sometimes leads to substantial errors in estimating the sea surface height and to extremely poor resolution of cross-shore bottom stress. The latter implies that cross-shore near-bottom transport is essentially neglected by traditional DAMs. / by Harry Leonard Jenter, II. / Ph.D.

Thesis (Ocean Engineer)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution. / Includes bibliographical references.

"January 1992." / "Technical report." "Funding was provided by the Office of Naval Research through Contract no. N00014-90-C-0098." Includes bibliographical references (p. 37-38).

Thesis (Ph. D.) - Massachusetts Institute of Technology, 1966. / Prepared under NR 083-157, Contract Nonr 1841(74) Office of Naval Research. Bibliography: leaves 184-187.

Thesis (Ph. D.)--Texas A & M University, 1982. / Vita. Includes bibliographical references (leaves 274-278).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1986. / Bibliography: p. 196-199.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998. / Includes bibliographical references (leaves 93-97). / by Mary Ann Schlegal. / M.S.