One challenge for Autonomous Underwater Vehicle (AUV) multibeam surveying is the limited ability to assess internal vertical agreement rapidly and reliably. Applying an external ellipsoid reference to AUV multibeam data would allow for field comparisons. A method is established to merge ellipsoid height (EH) data collected by a surface vessel in close proximity to the AUV. The method is demonstrated over multiple collection missions in two separate areas. Virtual tide corrector values are derived using EH data collected by a boat and a measured ellipsoid to chart datum separation distance. Those values are compared to measurements by a traditional tide gauge installed nearby. Results from the method had a mean difference of 6 centimeters with respect to conventional data and had a mean total propagated uncertainty of 15 centimeters at the 95% confidence interval. Methodologies are examined to characterize their accuracies and uncertainty contribution to overall vertical correction.

My artistic practice creates relationships between the abstract and the personal. I define the abstract in the context of my studio work as a material exploration of color and form. The personal encompasses autobiography in relation to my sense of time and place. In this text, I use my concept of oceanic tides (considered as a temporal and spatial shift between states) to chart my activities as an artist. These activities include making objects that change in character over time, and durational work including performance and video. Interwoven throughout Tides are narrative passages based on my personal experiences, including witnessing the total eclipse of the sun, a purple garden, a coincidence, and the death of a friend.

In this thesis three independent studies of tidal dynamics have been pesented. The first is an analytical study of continental shelf tides forced at the ocean boundary. Earlier studies have shown that the response for a sloping shelf and a flat shelf differ and that the response for a flat shelf changes when tides are incident at an angle. Other studies considered a sloping shelf but they did not take into account a possible non-zero depth at a coastal wall. This study shows that the effects of a sloping shelf, a coastal wall and obliquely incident tides an all significantly modify the response on the shelf. The modification increases with the width of the shelf, and in a wide shelf scenario, near resonance, it greatly modifies the response. Secondly, the Princeton Ocean Model in barotropic mode along with a tracer transport module has been used to study the tides of Sydney Harbour. The tidally induced residual circulation due to the semi-diurnal tide consists of a series of recirculating gyres which are due to the interaction of flow with topography. This study shows that in the harbour it is the Lagrangian residual velocity not the Eulerian residual velocity which determines the net transport of material over a tidal cycle. In addition, the flushing time of the harbour varies significantly in space, and the tidal mixing is restricted in the vicinity of the entrance. The third is a theoretical study of forced oscillations in a rotating, flat-bottomed, circular basin. This study shows that the direction of propagation of waves in a basin depends on the ratio of its radius to depth. At each latitude there is a critical value of this ratio and this value decreases with increase in latitude. Beyond this value, waves start to propagate around the basin in the opposite direction to the earth ???s rotation (clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere).The presence of friction increases this critical value which shows that friction plays an important role in determining the response.

Bibliography : p. 333-342. / xiii, 342 p. : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1994?

This thesis considers the problem of tidal and thermal propagation of water within a shallow estuary, with specific reference to the Port River Estuary in South Australia. A system of two - dimensional laterally integrated equations are obtained from the general three - dimensional equations of continuity, momentum conservation and thermodynamics by integration over the width of the estuarial channel, and this system is further integrated over depth to obtain a set of one-dimensional equations. A numerical model is developed from these equations, using explicit finite differences to approximate the tidal equations ( continuity and motion ) and implicit differences to model the temperature equation. The model is extended to include a number of interconnecting channels, and discusses boundary conditions to determine transports, elevations and temperatu along each of the channels. Verification of the numerical model is achieved by comparing results obtained from the model with analytic solutions for similar situations. These comparisons show good agreement between the two solutions. A two - dimensional numerical model is obtained by first non - dimensionalizing the laterally integrated equations with respect to the depth coordinate, and then using explicit finite differences to solve the equations of continuity, motion and temperature. Different schemes are considered in order to provide the best means of approximating the differential equations, and these are discussed with reference to stability, convergence and efficiency. The two models are applied to the Port River Estuary, where the Torrens Island Power Station pumps heated water into one of the channels within the estuary. Tidal elevations obtained from the models compare favourably with data collected at various points in the estuary. Unfortunately, no transport or temperature measurements are available to verify the models, but results obtained from both models are consistent. The temperature results tend to suggest that recirculation of heated water from the outflow region to the point where water is drawn into the Power Station does occur at most stages of a tidal cycle. This recirculation can lower the efficiency of the power station, and possible alternatives are put forward to prevent this becoming an economical problem for the Station. / Thesis (Ph.D.)--Department of Applied Mathematics, 1976.

The study is based upon the Vertical Line Array (VLA) of the Asian Seas International Acoustic Experiment (ASIAEX), dated from May 3, 2001 to May 16, 2001, in which the ambient noise was measured and the six frequencies (including 50, 100, 200, 400, 800, 1,200 Hz) were analyzed. The depth dependence of ambient noise levels in shallow water is not significant, and the fluctuations of ambient noise levels can be measured by Fourier analysis. With the similar analysis on static water pressure and temperature variation, the acoustic data has shown obvious in K1 and M2 tidal periods. The frequency dependence of ambient noise was also investigated, the lower frequency components, 50, 100, and 200 Hz, were mainly contributed from distant shipping noise, and the local wind was the dominating factor in higher frequencies such as 400, 800, and 1,200 Hz. This result was further verified by the increased levels at higher frequency due to the typhoon Cimaron during the experiment. Finally, the probability distribution function of ambient noise levels was calculated at each frequency, and was found the lower frequency ambient noise levels were not significantly affected by the typhoon as higher frequency. The threshold frequency of the ambient noise levels affected by the wind wave is about 400 Hz.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 130-136).

The majority of internal gravity wave energy in the ocean is produced by tidal flow over bottom topography. Regions of critical topography, where the topographic slope is equal to the slope of the internal gravity waves, is often believed to contribute most significantly to the radiated internal gravity wave power. Here, we present 2D computational studies of internal gravity wave generation by tidal flow over several types of topographic ridges. We vary the criticality parameter [epsilon], which is the ratio of the topographic slope to the wave beam slope, by independently changing the tidal frequency, stratification and topographic slope, which allows to study subcritical ([epsilon] < 1), critical ([epsilon] = 1), and supercritical ([epsilon] > 1) topography. This parameter variation allows us to explore a large range of criticality parameter, namely 0.1< [epsilon] < 10, as well as beam slope S, 0.05< S < 10. As in prior work [Zhang et al., Phys. Rev. Lett. (2008)], we observe resonant boundary currents for [epsilon] = 1. However, we find that the normalized radiated power monotonically increases with internal wave beam slope. We show that an appropriate normalization condition leads to a universal scaling of the radiated power that is proportional to the inverse of the beam slope 1/S and the tidal intensity I[subscript tide], except near [epsilon] = 1 where the behavior undergoes a transition. We characterize this transition and the overall scaling with the criticality parameter f([epsilon]), which is weak compared to the scalings mentioned before and only varies by a factor of two over the entire range of criticality parameter that we explored. Our results therefore suggest that estimates of the ocean energy budget must account for the strong scaling with the local beam slope, which dominates the conversion of tidal motions to internal wave energy. Thus we argue that detailed characterization of the stratification in the ocean is more important for global ocean models than high-resolution bathymetry to determine the criticality parameter. / text

published_or_final_version / Statistics / Master / Master of Philosophy

In a multi-planet system, gravitational interactions cause orbital eccentricity variations. For non-resonant systems, classical secular theory reveals that the eccentricities are vector sums of contributions from several eigenmodes. Examination of the eigenvectors often reveals subsets of planets that interact especially strongly as dynamical groups. Perturbations from other sources, such as tides, are shared among the planets through the secular interactions. If one planet's eccentricity is tidally damped, all the eigenmodes damp so as to leave a signature on their amplitudes. Therefore, if one desires to include some a priori tidal damping in an orbital fit, solutions should not assume the current eccentricity of that planet to be low, but rather for the eigenmodes that damp quickly to have low amplitude. The tidally perturbed planet may retain a substantial eccentricity, because some eigenmodes will be longer-lived. The secular eigenmodes, including relative damping rates, have been calculated for all 72 non-resonant extra-solar systems with adequate data. Tides also affect evolution of planets' semi-major axes, which is coupled with eccentricity evolution. A planet that, alone, would be quickly circularized so as to not experience much semi-major axis migration, could rapidly be forced into the star in the presence of an outer planet. Also, though such an inner planet may now be gone, the eccentricity of the outer planet could have been damped due to tides that acted on the inner planet. Any inferences about the primordial orbits of observed planets must consider these effects. For systems where the inner planet has not yet reached the star, the planets' eccentricities can be constrained for any particular assumed tidal dissipation factor Q', e.g. for the KOI-543 system, if the inner planet is rocky, the eccentricities must be<0.001. The habitable zone around low-mass stars is close to the star, precisely where tides are important. Low-mass stars are very long lived, and can be very old currently. A habitable planet likely needs tectonics for cycles that regulate the atmosphere, but a planet's internal heat will decay over long timescales. However, an outer planet could maintain the inner planet's eccentricity, allowing tidal heating to maintain long-term habitability. Secular interactions, coupled with tidal effects, may be critical for planetary habitability.