Tidally driven dynamics in Bonne Bay, Newfoundland
A suite of observations from May 2006 to March 2007 is used to describe the vertical structure and temporal variations of currents and hydrography on the sill of East Arm of Bonne Bay, Newfoundland. The instruments include a moored ADCP, multiple-frequency BioSonics echo-sounders, and a fixed hydrog...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
2008
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| Online Access: | https://research.library.mun.ca/9383/ https://research.library.mun.ca/9383/1/Peng_Wenjun.pdf |
| Summary: | A suite of observations from May 2006 to March 2007 is used to describe the vertical structure and temporal variations of currents and hydrography on the sill of East Arm of Bonne Bay, Newfoundland. The instruments include a moored ADCP, multiple-frequency BioSonics echo-sounders, and a fixed hydrographic package with CTDs and an ECO fluorometer. These observations provide a detailed description of circulation at different timescales and reveals that the tide is the dominant forcing over the sill. The M₂ tide is the most energetic tidal constituent and contributes roughly 70% of the total tidal kinetic energy. The M₂ baroclinic tide is detected only in summer when stratification is strong. It has a wavelength of 7 km and has an energy that is about 20% of the barotropic kinetic energy. The subtidal current over the sill has a fortnightly modulation associated with spring-neap cycles between late September and November 2006, which indicates that deep-water renewal is not controlled by wind forcing but rather by changes in the horizontal stratification due to variations in tidal amplitudes. High-frequency internal waves with period of 80 minutes are identified in the data from ADCP and BioSonics echo-sounders in summer, 2006. They display asymmetry during tidal cycles: the wave structure only develops on the ebb tide, and the amplitude is 3 m and group velocity is 35 cm/s. It has about 1% of the barotropic kinetic energy. The high-frequency internal waves are generated near the side of the inner basin and propagate towards the outer area. |
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