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1

Gagarin, Isa N. "TIDES". VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5399.

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Abstract (sommario):
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.
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2

Das, Pritha School of Methematics UNSW. "Modelling of ocean tides". Awarded by:University of New South Wales. School of Methematics, 1998. http://handle.unsw.edu.au/1959.4/19038.

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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.
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3

Bills, Peter John. "Barotropic depth-averaged and three-dimensional tidal programs for shallow seas /". Title page, contents and summary only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phb599.pdf.

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4

Stevens, Malcolm William. "A three-dimensional tidal model for shallow waters using transformations and variably spaced grids". Title page, contents and summary only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phs845.pdf.

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5

Li, Tak-wai Wilson. "Forecasting of tide heights : an application of smoothness priors in time series modelling /". [Hong Kong] : University of Hong Kong, 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13154357.

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6

Carrasco, Ana. "Internal tides in Dixon Entrance". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0035/NQ27115.pdf.

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7

Sroka, Sydney Glass. "Internal tides near steep topographies". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106773.

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Abstract (sommario):
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 93-96).
The primary contributions of this thesis include the first stages of development of a 2D, finite-volume, non-hydrostatic, [sigma]-coordinate code and beginning to apply the Dynamically Orthogonal field equations to study the sensitivity of internal tides to perturbations in the density field. First, we ensure that the 2D Finite Volume (2DFV) code that we use can accurately capture non-hydrostatic internal tides since these dynamics have not yet been carefully evaluated for accuracy in this framework. We find that, for low-aspect ratio topographies, the z-coordinate mesh in the 2DFV code produces numerical artifacts near the bathymetry. To ameliorate these stair-casing effects, and to develop the framework towards a moving mesh with free-surface dynamics, we have begun to implement a non-hydrostatic [sigma]-coordinate framework which significantly improves the representation of the internal tides for low-aspect ratio topographies. Finally we investigate the applicability of stochastic density perturbations in an internal tide field. We utilize the Dynamically Orthogonal field equations for this investigation because they achieve substantial model order reduction over ensemble Monte-Carlo methods.
by Sydney Glass Sroka.
S.M.
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8

Aslam, Tahmeena. "Internal tides in Whittard Canyon". Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/64047/.

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Submarine canyons are common bathymetric features incising the shelf edge and are known to trap and focus internal waves leading to high levels of turbulent mixing. Whittard Canyon, located at the Celtic Sea shelf edge, is a dendritic canyon where little is known about the internal tide, yet where it is postulated to have a huge impact on biology within the canyon and also play a role in the generation of nepheloid layers. High-resolution simulations of the M2 tide in Whittard Canyon using a modified version of the Princeton Ocean Model are used to determine the generation, propogation, spatial structure and dissipation of the internal tide within the canyon. Shamrock canyon and Brenot Spur are identified as key remote sources of internal tide generation, which modulate local generation in a flux-conversion feedback mechanism which causes the observed assymmetry in barotropic-tobaroclinic conversion within the canyon limbs. Depth-integrated baroclinic energy flux within the canyon is elevated, but variably so in different limbs, with values reaching >8 kW m¡1. The eastern limb of the canyon is notable for being particularly energetic. Enhancement of near-bottom baroclinic tidal currents are seen within the canyon with velocities reaching 0.4 m s¡1. The three-dimensional structure exhibits bottom intensification due to topographic focusing by the steep canyon walls, and the dominantly supercritical limb heads. Within the upper canyon the internal tide exhibits a typical mode-1 structure. Cores of baroclinic energy flux, in a dominantly up-canyon direction, form over the depth range of 1000-2500 m and are correlated with potential source regions for nepheloid layers. The sensitivity of the model to bathymetric resolution is tested and it is found that using 500 m resolution bathymetry results in domain-averaged conversion rates higher than for the smoothed bathymetries tested, highlighting the need for high-quality, high-resolution bathymetric datasets.
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9

Oliver, Sophia. "Modelling studies of the atmospheric tides". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365773.

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10

Ye, Feng 1969. "Dispersion of fine sediments in tides". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50014.

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11

Fok, Hok Sum. "Ocean Tides Modeling using Satellite Altimetry". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354040445.

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12

Hebel, Martin. "Tides Within: Concerto for Wind Ensemble". University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623167017549242.

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13

Kovalam, Sujata. "MF radar observations of tides and planetary waves". Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phk878.pdf.

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Abstract (sommario):
Copies of previously published articles inserted. Bibliography: p. 185-200. Data obtained from six radar stations covering a wide latitude range has been used to determine the global distribution of planetary waves and tides. In the process a number of data analyses techniques were considered for their characterisation.
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14

Mertz, Gordon James. "Atmospheric and oceanic 40- to 50-day oscillations in the source region of the Somali Current". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25933.

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Abstract (sommario):
Current and temperature data were acquired in the source region of the Somali Current, jointly by the Universities of Kiel and Miami, as part of the INDEX pilot studies. The data were acquired over a six-month period (January-July, 1976) which spans the springtime Monsoon reversal. The experiment and the data are described in Düing and Schott (1978). This thesis describes the results of the spectrum analysis of fluctuations found in data from the experiment's two southernmost sensor locations. It is found that, once the annual cycle is removed, most of the variance in these current and temperature records resides in subinertial fluctuations. The most prominent spectral feature is a 40- to 50-day peak. This 40- to 50-day period is coincident with that of the global-scale circulation cells found in the tropical atmosphere by Madden and Julian (1971 and 1972). The analysis of wind stress and wind stress curl data for the years 1976 and 1979 presented in this thesis indicate that the 40-to 50-day oscillation was present over the Western Indian Ocean during these years. It is suggested here that wind-forcing excites a long coastally trapped wave. To test this idea, a wind-forced quasi-geostrophic, three-layer model and a reduced-gravity model incorporating lateral mean current shear are applied to the Somali Current regime. Model results suggest that the wind forcing is strong enough to excite the observed current and temperature fluctuations.
Science, Faculty of
Physics and Astronomy, Department of
Graduate
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15

Hurford, Jr Terry Anthony. "Tides and Tidal Stress: Applications to Europa". Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1258%5F1%5Fm.pdf&type=application/pdf.

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16

Crabbe, Kendra Leigh. "Directional characteristics of inner shelf internal tides". Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FCrabbe.pdf.

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Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, June 2007.
Thesis Advisor(s): Timothy P. Stanton. "June 2007." Description based on title screen as viewed on August 13, 2007. Includes bibliographical references (p. 73-74). Also available in print.
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17

Allen, Sara E. "Florida Red Tides: Public Perceptions of Risk". [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002267.

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18

Kansowa, Tarek. "Earth tides, earthquake occurrence and earth deformation". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/180875/.

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An analysis of Earth deformation, earthquakes and tides has been undertaken using Earth tide and interferometric SAR data from ESA satellites. The ability of Earth tides to trigger earthquakes has been investigated by measuring the statistical relationship between earthquake occurrence and Earth tides. Analysing Earth tides data with earthquakes occurrence using Shuster’s test has shown that there is a correlation between Earth tides and earthquake occurrence. The significance of this correlation has been examined as a function of location, earthquake depth and magnitude. It has been found that the correlation is especially significant for low magnitude earthquakes. The two regions in California examined show similar correlations but significant differences in the phase angle of the correlation. Possible reasons for these differences and the role of ocean load tides are discussed in this thesis. SAR data are used to detect the Earth displacement related to two recent earthquakes in the Californian area. InSAR technique has been applied successfully to the Bam earthquake in Iran in 2003. The results for Earth displacements in the Parkfield area are less satisfactory but a number of interference fringes over a wide area due to a particular earthquake have been observed.
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19

Kumar, Aishwarya S. "Non-migrating tides in the Martian thermosphere". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85828.

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Abstract (sommario):
Previous studies have identified longitudinal structures associated with non-migrating tides in observations of the upper neutral atmosphere of Mars. MAVEN’s Imaging Ultraviolet Spectrometer (IUVS) observations of the upper atmosphere reveal variations in density with longitude at altitudes of 130 – 200 km, and can be used to identify non-migrating tides. These observations cover higher latitudes and allow for studying the local time variations of tides. The analysis presented here shows that the longitudinal structure attributed to non-migrating tides is dominated by wavenumber 2 and wavenumber 3 harmonics during the periods studied. Comparison with the Neutral Ion and Gas Mass spectrometer (NGIMS) shows a good agreement in wave amplitudes observed for the first two cases studied. The temperatures and 𝑂/𝐶𝑂# ratios from the IUVS L2 data files revealed an anti-correlation with the densities which confirms the theoretical interpretation from the linear wave theory.
Master of Science
There are waves internal to all fluids in our surroundings and daily lives, such as sound waves. Waves in the atmosphere are also fluid in nature. In planetary atmospheres, the scale sizes of some of these waves become comparable to the size of the planet itself. The waves interact with the structure of the surface of Mars to form a certain type of wave called “Non-migrating tides”. These waves have been observed in multiple previous studies in the upper atmosphere of Mars (~130 km and above). These waves cause the atomic and molecular content of the upper atmosphere to be displaced in a particular manner to form a unique structure. The structures formed are observed on a scale that covers the entire planet. It is by studying these structures in the upper atmosphere that it is possible to characterize the waves that control them and thereby understand their nature and impact. Understanding how these waves vary helps spacecraft to gain better control over mechanisms required to swing them into the desired orbit (location). This study uses the observations from an instrument aboard the MAVEN mission and compares it to the observations from another instrument aboard the same mission. The results of this study demonstrate that these “Non-migrating” tides play a vital role in controlling the behavior of the upper atmosphere.
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20

Quaresma, Dos Santos Luis. "Super inertial tides over irregular narrow shelves". Thesis, Brest, 2012. http://www.theses.fr/2012BRES0074/document.

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Abstract (sommario):
Les marées internes sont des processus dynamiques très répandus observés de façon intense près des marges continentales. Leur signature sur la surface libre de la mer est souvent observée sur les images satellites, montrant des systèmes d'ondes complexes au dessus des marges continentales irrégulières tels que la marge Ouest-Ibérique. Leur génération et leur distribution spatiale sont l'objet du présent travail, qui explore les processus physiques derrière la génération et la propagation de ces modes baroclines, au-dessus de canyons sous-marins et de promontoires, représentatifs des structures observées sur le talus Ouest-Ibérique. La solution de marée super inertielle est étudiée par le biais de simulations numériques, utilisant des configurations de topographie, soit réalistes soit idéalisée, en océan homogène ou stratifié (configuration bi couches et stratification continue). Les bassins océaniques sont dotés de talus et plateaux continentaux de faible profondeur qui détournent la propagation des marées océaniques de leur cours naturel. Les ondes de marée côtières sont ensuite réfléchies et/ou piégées sous différents modes possibles, fonction de la latitude, de la fréquence de forçage, du relief topographique et de la stratification de la colonne d'eau. Différents accidents topographiques, tels que les canyons sous-marins, les vallées, les promontoires et les bosses peuvent façonner des marges continentales afin de créer des pentes abruptes tangentielles au talus, qui deviennent effectivement des sites de production des marées internes. L'origine des marées internes se situe dans les forces d'attraction astronomiques, mais la répartition spatiale des solutions le long des marges continentales est distincte à travers le monde. La diversité du relief topographique module de façon spécifique les solutions de courant de marée barotropes, dont l'énergie est ensuite dissipée dans les modes baroclines en de nombreux endroits accidentés et à différents instants par rapport à la phase de marée.A mi-latitude, la force d'inertie terrestre divise le spectre de marée en ondes diurnes sub-inertielles et ondes semi-diurnes super-inertielles, donnant lieu à des ajustements en différents types de modes. La modélisation réaliste de la marée barotrope le long de la marge ouest-Ibérique vérifie cette différence de comportement et devient le point de départ de la présente thèse. Alors que les composantes diurnes génèrent des modes d'ondes continentales piégées le long du littoral, les harmoniques semi-diurnes montrent des structures de courants complexes, corrélées spatialement aux canyons sous-marins locaux et aux promontoires (pour lesquels on modélise une accroissement de l'amplitude du courant de marée associé à une inversion du sens de rotation).Ces distorsions super-inertielles des ondes de marée sont analysées et interprétées en utilisant des configurations de bathymétrie idéalisées. Les configurations canyon sous-marin et promontoires sont considérées comme des anomalies (sinusoïdale de signe opposé) de la largeur du plateau continental, situées au milieu du domaine modélisé. L'onde de marée monocromatic super-inertielle forcée aux limites, tient compte de l'hypothèse d'un plateau uniforme dans la direction tangentielle. Les résultats obtenus révèlent une distorsion importante du flux de marée qui peut être interprétée par la dynamique de la vorticité du fluide dans le cadre du principe de conservation du moment angulaire
Oceanic internal tides are ubiquitous dynamic features, densely observed near continental margins. Their sea-surface signature is frequently printed in remote sensing images, showing complex wave patterns over irregular shelves such as the West-Iberian margin. Their origin and spatial distribution is the subject of the present work, which explores the physics behind the generation and propagation of these baroclinic modes, over submarine canyon and promontory shelf features. It focuses on the study of the super-inertial tide solution by the use of numerical model simulations of realistic and idealized topography configurations, under homogeneous, two-layers and continuous stratified water columns. The ocean basins are flanked by shallow water continental margins that divert ocean tides from their natural course. Coastal tide waves are then reflected and/or trapped in several possible wave modes, function of the latitude, forcing frequency, topographic relief and water column stratification. Different shelf features, such as submarine canyons, valleys, promontories and bumps can shape continental margins to create abrupt along-shelf slopes that become effective internal tide generation sites
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21

Haselmaier, Lawrence H. "Computation of a Virtual Tide Corrector to Support Vertical Adjustment of Autonomous Underwater Vehicle Multibeam Sonar Data". ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2080.

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Abstract (sommario):
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.
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22

Muller-Wodarg, Igo Carl Friedrich. "Modelling tides propagating through the menopause into the earth's upper atmosphere". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268013.

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23

Stevenson, Ann. "Changing tides: the development of an archaeological exhibit". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25537.

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This thesis report is part of a larger thesis project which includes the museum exhibit Changing Tides and the UBC Museum of Anthropology Museum Note No. 13, entitled Changing Tides: The Development of Archaeology in B.C.'s Fraser Delta. This report chronicles the planning and production of this exhibit project and outlines the criteria on which it is based. The main objective of this project was to aid in the development of public appreciation for scientific archaeology. Justification for this objective is provided through a discussion of the role of public interpretation in archaeology. Funding, exhibit development, exhibit co-ordination and scheduling, exhibit conservation, Museum Note development, and related activities are discussed and evaluated. A series of appendixes are included which document the development of Changing Tides.
Arts, Faculty of
Anthropology, Department of
Graduate
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24

Wai, Siu-wah, e 衛兆華. "Red tides: a detrimentall threat to the environment". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31254135.

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25

Braviner, Harry Joseph. "Stellar and planetary tides at small orbital radii". Thesis, University of Cambridge, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709498.

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26

Wai, Siu-wah. "Red tides : a detrimentall threat to the environment /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20038203.

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27

Teeluck, Vijayantee. "Surface and internal tides above sea-floor topography". Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/6351/.

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Abstract (sommario):
Waves of long spatial scale (meaning wavelengths of hundreds or thousands of kilometres) and long time scale (meaning periods of hours or days) are important in a range of dynamical phenomena in the ocean. For example, these waves are fundamental to the dynamics of ocean tides, which are the focus of this study. Here we are concerned with both barotropic waves and internal waves, and the forcing of internal waves of tidal frequency (internal tides) by barotropic tides. After an introduction to the background and physical significance of this subject, the governing equations for long barotropic linear waves are set out and the underlying assumptions are discussed. We then turn to the issue of coastally-trapped barotropic waves, and review some simple solutions for the three main classes of such waves (the Kelvin wave, edge waves, and topographic Rossby waves). Detailed solutions are derived for these waves above a simple step topography, based upon an analytically derived dispersion relation, and these solutions are compared with numerical solutions above a smooth topography. A detailed solution is also derived for a family of topographic Rossby waves above a smooth slope in an unbounded domain, and the frequencies of these waves are shown to be in good agreement with the frequencies determined by numerical solutions with a coastline. Throughout, there is a focus on waves of tidal period. A simple solution of internal tide generation is also presented, in a two-layer fluid with a step topography (and no background rotation or coastline). Explicit analytical expressions are derived for the outgoing internal wave energy fluxes in this model, and are compared with estimates of energy fluxes in the real ocean.
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28

Withers, Paul G. "Tides in the Martian atmosphere, and other topics". Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289910.

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Abstract (sommario):
The dynamics of the martian upper atmosphere are not well-understood. I have identified the dominant tidal modes present in the upper atmosphere by comparing density measurements from the aerobraking of the Mars Global Surveyor spacecraft to predictions from classical tidal theory. Other observations and general circulation models have also provided constraints. I have presented a justification for why topography has a strong influence on the tides in the upper atmosphere. I have also studied sol-to-sol variations in density at fixed altitude, latitude, longitude, season, and time of day. I have developed a novel "Balanced Arch" technique to derive pressures and temperature from these density measurements that also estimates the zonal wind speed in the atmosphere. These are the first measurements of winds in the martian upper atmosphere. This technique can also be applied to anticipated data from Titan to measure winds in its upper atmosphere. I have developed techniques to derive density, pressure, and temperature profiles from entry accelerometer data, used them to investigate the entry of Mars Pathfinder, and discovered that surprisingly accurate temperature profiles can be derived without using any aerodynamic information at all. I have also investigated techniques to derive atmospheric properties from the Doppler shift in telemetry from a spacecraft during atmospheric entry and found that a surprisingly robust estimate of temperature at peak acceleration can be derived. I have discovered a network of tectonic ridges in the otherwise bland northern plains of Mars and studied their implications for a possible ocean in that area. I have tested the hypothesis that the formation of lunar crater Giordano Bruno was witnessed in 1178 AD and rejected it due to the lack of any observations of the immense meteor storm that must have followed the crater's formation.
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29

Arzani, Caterina. "La traduzione che non c’è. Torment: Tides of Numenera". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/17216/.

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The market of videogames has been growing more and more int the last years, reaching a revenue of more than 91 million dollars on a global scale. But while videogames enter the lives of more and more people, some companies choose to cut some languages from their internationalization projects. The project described in this dissertation analyses the case of Torment: Tides of Numenera, trying to discern the reasons that brought the developers to cut the Italian translation for the game, aiming to find how this choice has influenced the experience of Italian gamers. To this aim, the dissertation is organized in four main chapters. Chapter 2 examines the general characteristics of videogame localization, its polysemiotic nature and the added level of complexity given by the fragmentation typical of software syntax. Chapter 3 presents the details that compose the game’s identity: its genre, its predecessor and the world in which it is set. Chapter 4 contains the analysis of the actual localization project, including the technical, linguistic and textual issues faced during translation. Chapter 5 focuses instead on the reaction of the Italian public to the lack of a localization, both among the professionals of the sector and among the players. Finally, the project results are discussed, highlighting why the same reasons that bring a developer to cut the localization, also speak to the importance of a translation for the experience of Italian-speaking gamers.
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30

Najafi, Hashem Saberi. "Modelling tides in the Persian Gulf using dynamic nesting /". Title page, table of contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phn162.pdf.

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31

Collins, Julie Louise. "On the detectability of internal tides in Drake Passage". Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410078.

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32

Wurch, Louie L. (Louie Lorne). "Molecular insights into the niche of harmful brown tides". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68431.

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Abstract (sommario):
Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Recurrent brown tide blooms caused by the harmful alga Alureococcus anophagefferens have decimated coastal ecosystems and shellfisheries along the Eastern U.S and South Africa. The exact mechanisms controlling bloom formation, sustenance, and decline are unclear, however bottom-up factors such as nutrient type and supply are thought to be critical. Traditional assays for studying algal nutrient physiology require bulk community measurements or in situ nutrient perturbations. Although useful, these techniques lack the ability to target individual species in complex, mixed microbial assemblages. The motivation for this thesis is to examine the metabolic strategies utilized by A. anophagefferens for meeting its nitrogen (N) and phosphorus (P) demand at the cellular level using molecular tools that, even in the presence of complex microbial assemblages, can be used to track how nutrients influence the bloom dynamics of A. anophageferens in the environment. Chapter two examines the global transcriptional responses of A. anophagefferens to N and P deficiency. Results demonstrate that A. anophagefferens has the capacity to utilize multiple forms of organic N and P when inorganic forms become unavailable. Chapter three analyzed the global protein changes in response to P deficiency and P re-supply. Consistent with transcript patterns, A. anophagefferens increases protein abundance for a number of genes involved in inorganic and organic P metabolism when inorganic P is deficient. Furthermore, increases in a sulfolipid biosynthesis protein combined with lipid data suggest A. anophagefferens can adjust its P requirement by switching from phospholipids to sulfolipids when inorganic P is unavailable. Analysis of protein abundances from Pdeficient cells that were re-fed inorganic P demonstrates variations in the timing of turnover among various proteins upon release from phosphate deficiency. Chapter four tests the expression patterns of candidate gene markers of nutrient physiology under controlled culture experiments. Results show that expression patterns of a phosphate transporter and xanthine/uracil/vitamin C permease are indicators of P and N deficiency, respectively. Taken together, these findings provide insight into the fundamental and ecological niche space of this harnful algal species with respect to N and P and provide a platform for assaying nutrient controls on natural brown tide blooms.
by Louie L. Wurch.
Ph.D.
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33

Löffelmann, J., Friederike Lilienthal e Christoph Jacobi. "Trend analyses of solar tides in the middle atmosphere". Universität Leipzig, 2019. https://ul.qucosa.de/id/qucosa%3A74180.

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Using a mechanistic global circulation model, we analysed the trends of solar tides in the middle atmosphere. Forced by monthly mean assimilation of reanalysis data in the lower atmosphere and monthly adjusted CO2 and ozone distributions, the simulations represent a time period from January 1980 to May 2019. The time series of monthly mean wind and temperature amplitudes of all tidal components have been extracted from these data. Trend analyses by linear regression show prevailing negative trends in July and October for all tides and for all latitudes in the mesosphere and lower thermosphere. In April and January, however, trends are positive or negative, depending on the tidal component. Furthermore, the data set has been examined on possible trend changes via a statistical trend algorithm. A large part of those break points for the zonal wind amplitudes were found from 1985 to 1988 and from 2012 to 2015 for the investigated months January and April. Therefore, a clear relation between changes in the atmospheric ozone concentration and trends of the amplitudes of solar tides is not evident for the presented variables.
Unter Verwendung eines mechanistischen globalen Zirkulationsmodells wurden Trends von solaren Gezeiten in der mittleren Atmosphäre analysiert. Die Simulationen, die in den unteren Atmosphärenschichten mit monatlich gemittelten Reanalysedaten angetrieben wurden sowie mit angepassten CO2 und Ozonverteilungen, decken einen Zeitraum von Januar 1980 bis Mai 2018 ab. Aus diesen Daten wurden Zeitreihen für Monatsmittel in den Amplituden des Windes und der Temperatur für alle vier Gezeiten herausgefiltert. Die über lineare Regression gewonnen Trends ergeben -global betrachtet in der Mesosphäre und unteren Thermosphäre - vorwiegend negativsignifikante Trends im Juli und Oktober. Im April und Januar können jedoch je nach Gezeit und Parameter positive wie auch negative Trends vorkommen. Weiterhin wurden die Datenreihen auf mögliche Trendänderungen mit Hilfe eines statistischen Algorithmus untersucht. Ein Großteil dieser Trend-Wendepunkte in den Zonalwindamplituden liegen für die untersuchten Monate Januar und April in den Jahren von 1985 bis 1988 und von 2012 bis 2015. Eine direkte Verbindung zwischen Änderungen in der atmosphärischen Ozonkonzentration und Trends in den Amplituden solarer Gezeiten lassen sich in den hier behandelten Größen daher nicht ableiten.
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34

Hoppa, Gregory Vincent 1972. "Europa: Effects of rotation and tides on tectonic processes". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282763.

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Tides due to orbital eccentricity may have a substantial effect on the rotation and tectonics observed on Jupiter's moon, Europa. A direct measurement of Europa's rotation rate has been made by measuring the positions of surface features relative to the terminator in both Voyager and Galileo images. From these measurements I have found that the rotation of Europa relative to the direction of Jupiter is <0.5° over a 17 year period, i.e. one rotation with respect to Jupiter would require at least 12,000 years. Non-synchronous rotation is also a significant source of global stress which, combined with the diurnal tidal stress, provides a failure mechanism resulting in tensile cracks on a global scale. The stress associated with rotational and diurnal tides can also explain the orientations and age relationships observed regionally in Europa's northern hemisphere. Additional global scale linear features also strongly correlate to these stress fields suggesting that they too may have also formed as cracks. After crack formation, diurnal tides may significantly affect the evolution of cracks through either ridges formation, regional extension, or strike-slip motion. The process of tidal shear displacement is analagous to actual walking. Mapping of five different regions on Europa has revealed 121 strike-slip faults. Based on these observations, Europa appears to support the formation of right-lateral faults in the southern hemisphere and left-lateral faults in the northern hemisphere. The theory of tidal walking predicts exactly that dichotomy on average over the hemispheres. Additionally, all of the mapped strike-slip faults were associated with double ridges and bands, but none were detected along cracks. Thus, cracks (even older ones) without ridges apparently have not generally penetrated to a decoupling layer, consistent with models for ridge formation that require cracks to penetrate to a liquid water ocean.
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35

Rosier, Sebastian H. R. "The interaction between tides, ice shelves and ice streams". Thesis, Bangor University, 2015. https://research.bangor.ac.uk/portal/en/theses/the-interaction-between-tides-ice-shelves-and-ice-streams(0590227d-ae56-4a4d-8e5b-302bbe768774).html.

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Observation of ice-stream and ice-shelf flow has revealed interaction with the ocean tide, in some cases far upstream of the grounding line. Ice-stream velocities can be greatly affected by local ocean tides at a variety of timescales but of particular interest is a fortnightly modulation in flow that has been observed on the Rutford Ice Stream. This frequency is absent in the forcing, far stronger than the dominant tidal constituent signals and has been observed far inland. Understanding what mechanism can produce this signal can provide a window into mechanisms at the base of the ice stream that affect its flow. A consequence of this nonlinearity is that the mean flow of the Rutford Ice Stream is increased in comparison to a situation where no tidal forcing is present, implying that changes in tides could alter the long term flow of ice from Antarctica. Since local tides are sensitive to bathymetry which can change drastically due to changes in ice-shelf geometry and grounding line position, a feedback exists between tides and the ice sheet whereby changes in the flow of ice could alter tides which in turn would change the ice velocity. This thesis presents results from both ice-stream/shelf and tidal models to investigate these two mechanisms. Firstly a nonlinear 3D viscoelastic full-Stokes finite element model explores possible sources of nonlinearity that can produce fortnightly modulation in ice-stream flow far upstream of the grounding line. This model looks at stress transmission, grounding zone flexure, hydrology and grounding line migration and the conclusion is that tidally-induced changes in the subglacial water pressure play the largest role in producing this effect. Then, the OTIS tidal model is used to demonstrate that reduction in the thickness and/or extent of ice-shelves, in particular the Filchner-Ronne ice shelf, could greatly impact both tidal amplitudes and dissipation rates in the region. The research in this thesis clearly shows the importance of tidal interactions with the Antarctic ice sheet and that these are not limited to short temporal timescales.
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36

Oliveira, Gustavo Henrique. "Analysis of M2 tidal signatures in synthetic aperture radar images of Delaware Bay". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 111 p, 2008. http://proquest.umi.com/pqdweb?did=1456288331&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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37

Clarke, Suzanne. "Advective/diffusive processes in the Firth of Forth". Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295277.

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38

周國榮 e Kwok-wing Chau. "Computation of tidal hydraulics and water quality using the Characteristic Galerkin method". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B3121213X.

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39

Geißler, Christoph, e Ch Jacobi. "Forcing of the Quarterdiurnal Tide". Universität Leipzig, 2018. https://ul.qucosa.de/id/qucosa%3A31792.

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Ensemble calculations for the period from 2000 to 2010 were carried out with the middle and upper atmosphere model (MUAM), and an analysis of the quarterdiurnal tide is performed. The global temporal and latitudinal distributions of the quarterdiurnal tide are modeled with MUAM, and their forcing mechanisms are examined. The quarterdiurnal tides show a similar distribution over the year in the northern and southern hemisphere, with maxima of the amplitude in late winter and spring as well as in autumn. In the latitude-height distribution is also shown that the largest amplitudes of the quarterdiurnal tide are seen at midlatitudes. Due to the decreasing density with height, there is a general increase of the tidal amplitudes with height. The results of the forcing analyses show that direct solar forcing is most important, but also that non-linear forcing and gravity wave interaction with other tides have a non-negligible influence on the quarterdiurnal tide in the middle and upper atmosphere.
Mit dem Modell für die mittlere und obere Atmosphäre MUAM wurden Ensemble-Berechnungen für den Zeitraum 2000 bis 2010 durchgeführt und die vierteltägigen Gezeiten analysiert. Es wird auf die globale zeitliche und räumliche Verteilung der vierteltägigen Gezeiten eingegangen und deren Anregungsmechanismen untersucht. Die vierteltägigen Gezeiten zeigen einen ähnlichen Verlauf über das Jahr auf der Nord- und Südhalbkugel mit Maxima der Amplitude im späten Winter und Frühjahr sowie im Herbst. Ein ähnliches Bild zeigt sich auch für die Verteilung im Breiten-Höhen-Schnitt, wo die größten Amplituden der vierteltätigen Gezeiten in den mittleren Breiten zu finden sind. Aufgrund der abnehmenden Dichte mit der Höhe ist eine allgemeine Zunahme der Amplituden mit der Höhe zu beobachten. Es zeigte sich, dass der direkte solare Antrieb am stärksten ausgeprägt ist, aber auch, dass der nichtlinearer Antrieb und die Interaktion von Schwerewellen mit anderen Gezeiten einen nicht zu vernachlässigenden Einfluss auf die vierteltägigen Gezeiten in der mittleren und oberen Atmosphäre haben.
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40

Mitchell, Andrew James. "Numerical Modelling of Tides and Tsunamis in Ancient Epicontinental Seas". Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523740.

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41

Guo, Chuncheng. "Investigation of baroclinic tides in the northern South China Sea". Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1500.

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Baroclinic tides result from the interaction of barotropic tides with topography in stratified oceans. They play an important role in driving deep ocean mixing. In this research, investigations of the dynamics of baroclinic tides and internal solitary waves (ISWs) in the northern South China Sea (SCS) are conducted, mainly by means of the Massachusetts Institute of Technology general circulation model (MITgcm). Firstly, simulations of internal wave generation at the Luzon Strait (LS) are carried out. By conducting three-dimensional (3D), high-resolution experiments, it was found that the generated wave field features a multi-modal structure: large, pronounced ISWs of first mode (amplitude ~120 m) and second mode (amplitude ~120 m) were reproduced. The two north-south aligned ridges in the LS contribute together to the generation of the second mode ISWs, whereas the easternmost ridge of the two is responsible for the first mode ISWs. It was found that multiple generation mechanisms of internal waves could occur in this region, and overall it belongs to a mixed lee wave regime. A specific type of short internal waves arose during the 3D simulation. These ride on a second mode ISW with similar phase speed, trailing a first mode ISW. The short waves possess wavelengths of ~1.5 km and amplitudes of ~20 m, and only show up in the upper layer up to a depth of ~500 m. Scrutiny of the generation process showed that these short waves appear in two distinct regions and are produced due to two mechanisms, namely, the disintegration of an inclined baroclinic bore near the LS, and the overtaking of a second mode ISW in the deep water by a faster first mode ISW. Robust evidence has been sought from satellite imagery and by solving the theoretical Taylor-Goldstein Equation to verify their existence. The effects of superposition of multiple tidal harmonics (diurnal and semidiurnal) on the resultant ISW generation were investigated. It was first found that, by analyzing historical observational data, the occurrence of ISWs in the far-field always follow strong semidiurnal barotropic tidal peaks in the LS, regardless of whether it is the maximum for the diurnal or total tidal strength. However, modelling results of MITgcm and a linear internal tide generation model demonstrate that the diurnal tidal harmonics modulate the arrival time and amplitude of the propagating ISWs. Specifically, it leads to the emergence of the so-called A and B type ISWs and an alternation and transition between the two. Secondly, the shoaling process of ISWs in the northern SCS slope-shelf area is investigated. A series of two-dimensional (2D) experiments are set up to study the shoaling of a large-amplitude second mode concave ISW over a linear slope that resembles the SCS slope. Modelling results show that a strong transformation of the wave profile starts to take place when the wave is approaching the shelf break. A convex type wave is born at the trailing edge of the incident wave and gradually disintegrates into a group of ISWs due to the steepening of the rear wave profile. The frontal face of the wave gets flatter when travelling on the slope, but forms a steep structure right above the shelf break. However, this steep structure shows no tendency to evolve into an ISW: instead, it gets increasingly flat again while evolving on the shelf. The trailing convex wave packet travels faster and merges with the frontal concave wave. Finally, a wave packet with rank-ordered convex ISWs moves forward steadily on the shelf. Energy transfer to the ambient modes is evident, as both first mode and higher modes are clearly seen during and after the shoaling process. First mode ISW evolution is studied too by performing 3D, high-resolution experiments over the wide northern SCS slope and shelf area. It was found that the wave profiles change drastically near the shelf break and the Dongsha Atoll. In agreement with satellite imagery, the wavefront of the leading ISW becomes more spatially oblique with respect to its original orientation as it progresses westward due to the inclination of the slope in the topography. Wave disintegration is prominent in the shallow water zone, and wave polarity reverses near the turning point (at the 130 m isobath), which is consistent with the predictions of weakly nonlinear theory. A series of 2D experiments were set up to inspect the effects of rotation on the shoaling ISW. The results indicate that under the rotation, upon reaching the continental shelf, one shoaling ISW could disintegrate into one ISW packet and one secondary solibore that contains a number of rank-ordered waves with much shorter wavelength than an ISW. The secondary solibore is very pronounced in the northern portion of the northern SCS slope and shelf, but could hardly be discerned in the southern portion, which is consistent with the outcome of 3D simulations.
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42

Pickering, Mark. "The impact of future sea-level rise on the tides". Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/367040/.

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Tides (along with mean sea-level and surges) are a key component in coastal extreme water levels. This investigation begins by assessing the effect of future sea-level rise (SLR) on the tides of the northwest European Continental Shelf. Tides here are dominated by semidiurnal constituents; therefore the focus is on changes in the M2 constituent and the spring and neap tides. The validated operational Dutch Continental Shelf Model is run for the present day sea-level as well as uniform 2 and 10m SLR scenarios. M2 tidal amplitude responds to SLR in a spatially non-uniform manner, with substantial amplitude increases and decreases in both scenarios. The North Sea M2 tidal response is not proportional to SLR between 2 and 10m. In the 2m SLR scenario the M2 constituent is particularly responsive in the resonant areas. Changes in the spring tide are generally larger (-49cm St. Malo to +35cm Cuxhaven) than those in the M2, neap or shallow water tides. With SLR the depth, wave speed and wave length are increased causing changes in near resonant areas. In expansive shallow areas SLR also causes reduced energy dissipation by bottom friction. These mechanisms result in the migration of tidal amphidromes and complex patterns of non-proportional change in the tide with SLR. These substantial alterations to the tides are contrary to some previous studies. These results motivate a subsequent investigation into the effect of future SLR on the global tides. We use a fully global forward tidal model, OTISmpi, to simulate the response of the four primary tidal constituents (M2, S2, K1, O1) as well as mean high water (MHW) and maximum range to various SLR scenarios. Attention is paid to changes at the 136 largest coastal cities (populations >1 million), where changes would have the greatest significance. A refined model setup is shown to have good skill at representing the present day tides. Uniform SLR scenarios 0.5-10m with fixed coastlines show the tidal amplitudes in shelf seas globally to respond strongly (increases and decreases) and non-proportionally to SLR. The changes in K1 and O1 tides are confined to Asian shelves. With 0.5m, 1m and 2m SLR MHW changes exceed ±10% of the SLR at 13, 13 and 10 of the 136 cities, respectively. Uniform SLR scenarios including coastal recession show a stronger and increasingly negative MHW response. The regularly opposing signs of change between the fixed and recession cases are explained through the opposing effect of the perturbations on the natural period of oscillation of the basin. These results suggest it may be possible to influence the sign of the tidal amplitude change through coastal management strategies. Non-uniform SLR, due to ice melt, causes the largest difference from the uniform SLR tidal response at high latitudes, in the near field (diminished response) and far field (amplified response) of the mass loss. Changes in the tide will influence: coastal flooding, renewable and nuclear power generation, water reliant industry, sediment transport, dredging, shipping, tidal mixing fronts and intertidal habitats.
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43

Dutton, Anthony. "The Tides of the Tourism Complex at La Paz, Mexico". Diss., North Dakota State University, 2013. https://hdl.handle.net/10365/27182.

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By 1940, the outlying Mexican territory of Baja California Sur faced an uncertain future. The extractive industries of mining and pearling had collapsed in the southern areas of the peninsula, and the remaining economic activities of agriculture and fishing held little prospect for growing the population and fueling development. The solution adopted by local government, boosters, and the federal government was to promote international tourism. The rise of the tourism complex at La Paz represented a local response to the regional problems of economic underdevelopment and isolation, and its decline began with the intense federal involvement in funding the comprehensive tourist center at Los Cabos. From the 1940s through the late 1960s, La Paz tourism represented a sustainable model, rooted in place while maintaining and benefitting from the existing characteristics of Baja California Sur. Experiencing transition in the late 1960s and 1970s, Los Cabos underwent a transformation into a sun-and-sand mega-resort, and La Paz shifted to host a wave of national tourists attracted to the free trade zone. The region entered a phase of frenzied expansion of tourism infrastructure, but the inability to sustain this boom led to a bust in La Paz tourism in the early 1980s, and the regional dominance of Los Cabos. The decline of La Paz tourism during that period deepened as the national government gave priority to the development of Los Cabos, creating a tourist pole built along the same model as Canc?n.
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44

Van, Laerhoven Christa Lynn. "Multi-planet Extra-solar Systems: Tides and Classical Secular Theory". Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/321296.

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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.
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45

Frey, Sarah E. "Characterization of instabilities in the problem of elastic planetary tides". Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280697.

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In 1911, A. E. H. Love published a linear elastic model for the tidal deformation of planetary bodies. Using numerical techniques that were unavailable to Love, surprising behaviors of the tidal solution have been found: tides of finite, even substantial, height are possible in the presence of an infinitesimal tide raiser, thus indicating some sort of instability. The Love tidal model was for the deformation of a homogeneous sphere. In order to better understand the nature of the instabilities in this model, I consider the effect of adding a radially dependent density profile to the model. For a given singularity, an increase in the initial density gradient causes the singularity to change locations in parameter space. For steep enough density gradient, the singularity is pushed outside the realm of physically meaningful parameter space for certain initial radial density profiles. Self-gravitation appears to be the likely mechanism for the driving of the tidal instability. The nature of the behavior of self-gravitation will be studied by considering an exact elastic formulation of the problem. In this way, a more complete view of the processes involved in the tidal deformation of a body can be explored. I find that each of the curves of singularity loci observed in the tidal problem correspond to instabilities in different modes for the exact elastic self-gravitation problem.
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46

Ho, Kin-chung. "Subtropical red tides and their ecological significance in Hong Kong waters /". [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12997213.

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47

Cushanick, Matthew Stephan. "Analysis of nearshore currents near a submarine canyon". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FCushanick.pdf.

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Thesis (M.S. in Applied Science (Physical Oceanography))--Naval Postgraduate School, June 2005.
Thesis Advisor(s): Thomas H.C. Herbers. Includes bibliographical references (p. 45). Also available online.
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48

Webb, Anthony James. "The propagation of the internal tide around a bend in Knight Inlet, B.C". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25997.

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This thesis seeks to answer the question "how much of the internal tide propagating up Knight Inlet, B.C. is reflected by a right-angled bend ?" The internal tide in Knight Inlet is generated by the interaction of the barotropic tide with a shallow sill seaward of the bend. It then propagates in both directions as a travelling Kelvin wave. The up-inlet propagating wave then encounters the bend, where some of it may be reflected. This question is looked at with both theory (Chapter 2) and observations (Chapter 3). The theoretical study investigates the propagation of a Kelvin wave around a bend in a channel. The solution of the linearised long wave equations is expressed as a truncated series of cross-channel modes in each of three regions. The solution is matched across the two common boundaries by a least squares point matching process. The "rectangular bend" gives unsatisfactory results because of a singularity in the velocity field at the sharp inside corner. However, the "annular bend" gives good results. The bend acts as a diffraction grating, with total transmission for certain bend angles and "lobes" of high reflection for intermediate angles. Bends to the left give rise to the same reflection as bends to the right of the same angle, even if the incident Kelvin wave has a small cross-channel decay scale. For the parameters corresponding to the M₂ internal tide in Knight Inlet, the energy flux reflection coefficient is very small, much less than 1%. The method of solution breaks down inexplicably for diurnal tides. The observational study is based upon 2⅓ months of cyclesonde current meter data from four stations in Knight Inlet taken during the summers of 1981 and 1983. The vertical profiles of amplitude and phase of the M₂ constituent of longitudinal velocity and density fluctuations are found to be the same from month to month at a particular station, but different from station to station. These complex amplitude profiles are decomposed into a truncated series of normal modes for waves propagating both up-inlet and down-inlet. The phase speeds and zero-crossing depths of the normal modes do not agree with those calculated by Farmer and Smith (1980a) using 1977 data. Two simple models of the stratification are used to explain the differences in the normal modes in terms of differences in the Brunt-Väisälä frequency profile used to calculate them. At the two stations up-inlet of the sill, acceptable fits can be obtained using only two up-inlet propagating waves, indicating that the data are compatible with the low reflection found in the theoretical study. When down-inlet waves are included in the fit, their amplitudes are found to be small, although care must be taken to avoid trying to fit too many modes since some of them are highly correlated in the depth range for which data are available. At the two stations seaward of the sill, the up-inlet energy flux is of the same order of magnitude as the down-inlet flux, indicating a second source of internal tide seaward of those two stations. The results indicate that only 30-50% of the power removed from the barotropic tide is being fed into the internal tide in the summer. This conclusion is at variance with that of Stacey (1985), whose model shows that most of the power lost from the barotropic tide is being fed into the internal tide. A consistent interpretation of these results is that most of the power lost from the barotropic tide initially goes into the internal tide, but that 50-70% of it is rapidly dissipated through turbulence within a couple of kilometers of the sill. The low frequency component of the velocity signals from the cyclesonde data is also presented (Chapter 4), with a brief analysis . The monthly averaged residual velocity profiles are also found to be fairly repeatable from month to month at a particular station, but different from station to station. These profiles could be useful in validating general circulation models.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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49

Basker, Guy Ashbourne. "The determination of mean sea level using GPS". Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254467.

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50

Venn, J. F. "Shallow sea tidal friction and sediment transport". Thesis, London Metropolitan University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238297.

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