碩士 / 國立臺灣海洋大學 / 海洋環境資訊學系 / 100 / The Taiwan Strait (TS) is a 180×600 km shelf channel located between Taiwan and China. We analyzed five ADCP acoustic Doppler current profilers (ADCPs), four were deployed along the central part of the TS distributed uniform from Taichung to Wuchung and one was deployed in the Peng-Hu Channel (PHC). The data period is 1999-2001. In the general phase, tidal motions are dominated by barotropic component in TS due to shallow bathymetry and weak stratification.
In this study, using in-suit data accompanying with OTPS (OSU Tidal Prediction Software), we found that the barotropic diurnal/semidiurnal tidal motions almost flowed along the topography trend of the strait. The current magnitudes of barotropic diurnal tides were 0.1~ 0.13 m/s in the central part of the TS and PHC. The current magnitudes of barotropic semidiurnal tides eastward decrease in the central part of TS, and the maximum magnitude of semidiurnal barotropic tidal current were observed in the PHC(~ 0.9 m/s), much stronger than that in the central TS. Also, the magnitudes of barotropic tidal currents were enhanced by the rising and nearshore narrow channel in the TS. Meanwhile, the baroclinic diurnal/semidiurnal tidal motions were not significant in the general phase, in TS, and the magnitudes were 30~50% and 20~35% of the magnitudes of the barotropic diurnal/semidiurnal tidal motions, respectively. The baroclinic tides were dominated by first-mode baroclinic tidal motions.
The depth-integrated kinetic energy (KE) of the baroclinic tides revealed nearly spring-neap circle. However, KE of baroclinic tides were not only effected by the circle, other external events such as typhoon and eddy in the South Chain Sea could also enhance the KE of the baroclinic tides in the central part in TS. Meanwhile, the time lag (> 50hours) of the KE between the barotropic and baroclinic tides implied that internal tides were remotely generated in the Luzon Strait and subsequently proceeded to TS via South China Sea.
Compiling typhoon track、Sea Surface Temperature (SST) and Sea Level Anomaly (SLA), we conclude that the internal tides could be intensified in the presence of horizontal fronts in the northern South Chinese Sea (SCS). The fronts could be produced by the typhoon-induced cold wake or cold eddy. As our observation, the strong mode-1 semidiurnal baroclinic tides were intensified, with a maximum velocity of ~0.27 m/s. The maximum depth-integrated kinetic energy of semidiurnal internal tides after the time of the thermal fronts impact were 1.5~2 times of those in the time of spring tide. And the enhancement of internal tides were the most remarkable in the west of strait (Mainland China side).
| Identifer | oai:union.ndltd.org:TW/100NTOU5282047 |
| Date | January 2012 |
| Creators | Yu-Lin Sung, 宋雨霖 |
| Contributors | Ming-Huei Chang, 張明輝 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 54 |
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