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The knowledge of the ocean environment, especially its littoral/coastal waters, is important for current and future naval operations. In particular, an accurate description of the mesoscale variability of the surface and subsurface currents is essential for optimizing Navy missions. This study determines that different types of topographic smoothing and the addition of a volume constraint to a sigma-coordinate model significantly influences the generation, evolution, and maintenance of not only the surface and subsurface currents, but also other features (upwelling, meanders, eddies, filaments, Mediterranean Outflow, and Meddies) in the Northern Canary Current System (NCCS). The NCCS is chosen for this study for its classical upwelling and equatorward surface current as well as the unique impact of the Mediterranean Outflow. The sound speed structure of these features is examined to establish which regions of the NCCS experience the largest changes in sound speed and the most intense gradients. This study demonstrates that features of classic littoral/coastal eastern boundary current systems, like the NCCS, have an important impact on the sound speed structure which can significantly impact Navy sonar operations.

The intensification of cyclonic winds in the Gulf of Alaska during winter belies the relatively constant geostrophic circulation as being indicative of actual flow. In the absence of direct current measurements, effects of various meteorological phenomena have been eliminated from monthly mean sea level measurements over the decade 1950 to 1959, and the resulting height anomalies equated to monthly mean Sverdrup transports. A linear relationship is obtained, except during summer when it permits an estimate of the increase in recorded sea level due to runoff. The data suggest that during summer the geostrophic transport is a good indication of general flow, but that during winter the distribution of mass does not adjust to the Sverdrup transport, and the resulting barotrophic flow is about one and one-half times the geostrophic flow during this period. Mean seasonal Sverdrup transport indicates maximum recirculation in the Gulf of Alaska gyre during winter, a reduced but equal recirculation during summer and fall, but none during spring. These results conflict with existing interpretations of flow in the Gulf of Alaska, and should form the basis for renewed oceanographic explorations in this region. / Graduation date: 1969

The fall-winter surface current field off Oregon was determined by analysis of ten years of drift bottle data. Computer programs were developed for generating bottle tracks on a numerical grid, for interpolating bottle velocity components to fill void grid points and for smoothing irregularities in the velocity fields. Charts are presented showing the spatial distribution of surface currents determined in the study area of 5° latitude by 2-1/2° longitude. The mean currents for the fall-winter season have a predominantly northerly flow with speeds increasing from the south to the north (from 0.01 to 0.35 knots). This probably is a consequence of the increase in speed of southerly winds from south to north in the study area during the fall-winter season. The northly flow in October during the years 1961-70, when compared with the dominant southerly flow during this month from measurements prior to 1935, may indicate a major change of Davidson-California Current System within the past forty years. Apparent onshore flow may be introduced by bottle diffusion; this flow is prominant at all latitudes along which bottle releases are concentrated. An offshore flow component north of 46°30'N may be related to the Columbia River discharge and the westward extension of land. / Graduation date: 1973

A three component drag probe has been built, calibrated, and used to measure velocities beneath deep water ocean waves and turbulence in a tidal channel. Simple variable inductance devices which may be submerged in water were used as displacement transducers and the associated electronics provided voltage outputs which were proportional to the three components of force that were exerted on a small 5 cm diameter sphere. The force components were due to both the water drag force and the water inertial force in an accelerating flow field. Techniques are described for interpreting measurements made with the drag probe and for obtaining the three velocity components from the measured force components. From the drag probe calibration and its use in the field, it is concluded that the drag probe is a suitable instrument for the measurement of wave velocities and turbulence. Modifications are suggested to improve the performance of the drag probe. For the wave velocity measurements, the experimental results indicate that linear wave theory is adequate to describe the relations between the wave pressure and the wave velocity components. At frequencies higher than the predominant wave frequency the velocity spectra are roughly proportional to f⁻³ where f is the frequency in Hz. The wave velocity components were used to obtain an estimate of the directional energy spectrum. From the measurements in a tidal channel, it appears that the instrument is suitable to measure turbulent fluctuations with scale sizes larger than about 20 cm. If the turbulence were isotropic the velocity spectra would be proportional to f[⁻⁵/³]. Due to the influence of boundaries, the flow was not isotropic but the results appear to be consistent with other observations that turbulent velocity spectra usually show a f⁻¹ to f⁻² behavior and are quite different from wave velocity spectra. / Graduation date: 1971

Hydrographic data and drogue observations were used to describe the circulation and water masses in the upper 500 meters of the region of the entrance to the Gulf of California in the early spring of 1970. The thermohaline structure of the water and the general circulation in the vicinity of the entrance to the Gulf of California indicated that four water masses were present. California Current water on the western side of the entrance, Subtropical Surface water in the middle part and Gulf water on the eastern side. Underlying these three waters, Subtropical Subsurface water was found from about 150 to 500 meters. The geostrophic calculations indicate that a broad region of outflow from the Gulf existed on the eastern side associated with a marked upward displacement of isopycnals towards the east. Speeds were near 30 cm/sec at the surface and decreased to less than 3 cm/sec at 300 meters. Outflow also occurred on the western side, near the Baja California coast, at lower speeds. Inflow to the Gulf was observed near the middle part of the entrance at speeds of 30 to 40 cm/sec at the surface, decreasing to less than 6 cm/sec at 300 meters. The drogue observations were in agreement with the general circulation pattern inferred from geostrophic currents. Drogue and geostrophic velocities showed agreement better than 70% at 10 and 50 meters. The decrease of geostrophic velocity with depth indicates that a baroclinic condition existed. Comparison of these velocities with the drogue measurements indicates that the baroclinic circulation was predominant in the upper 100 meters. In the upper 150 meters the low salinity water from the California Current was flowing into the Gulf. The high salinity Gulf water was found in the regions of outflow as to be expected to avoid accumulation of salt inside the Gulf by strong evaporation. / Graduation date: 1975

The oceanic phenomenon of upwelling along the Oregon coast is examined. Upwelling in both the open ocean and coastal regions is discussed. An idealized model is used, envisaging the ocean off Oregon to consist of homogeneous surface and deep layers separated by a pycnocline. The equations of motion are solved to yield the vertical velocity at the base of the surface layer. A comparison is made between the model and results inferred from hydrographic data. In the open ocean region qualitative agreement is observed between the wind stress curl and the depth of the surface layer. Geostrophic meridional transports relative to the 1000 decibar surface were computed and found to be of the order of the uncertainty. In the coastal upwelling region surface layer zonal transports were computed from the meridional component of the mean wind stress and compared with values inferred from oceanographic data. Coastal upwelling along the Oregon coast is clearly associated with the northerly (longshore) component of the wind stress. / Graduation date: 1964

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1984. / Includes bibliographical references (p. 175-181).

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 127-130).

Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, March 2003. / Thesis advisor(s): Leslie K. Rosenfeld, Carlyle H. Wash. Includes bibliographical references (p. 85-86). Also available online.