UBC Theses and Dissertations
Prototype of a continental shelf tide gauge Galloway, James Lewis
Specifications and design for a self-contained tide gauge are presented. The gauge is suitable for immersion to a depth of 1000 meters for a period of one year with a five minute sample rate. A Vibrotron absolute pressure transducer is the sensing element with pressure measured to an equivalent water height of one millimeter. Instrumental and oceanic filtering of wind waves and tradeoffs in sampling techniques are investigated. Storage and reduction of data is arranged to provide useful statistical information on instrument performance. Transducer calibration data analysis indicates that careful choice of calibration polynomial can significantly improve accuracy of tidal data. In situ tests and analysis of results indicate adequate instrument performance, but high precision comparisions between sea bottom pressure and measured water height are of limited value in the test region due to variations in mean water density. Spectra results reveal the presence of seiches distinctive to the test region. Comparisions between shore-based staff readings and offshore pressure data indicate the possible presence of unusual dynamic water density structure at the test site.
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