碩士 / 臺灣大學 / 海洋研究所 / 98 / The volume transport from Taiwan Strait to East China Sea is 50 times more than that from Yangtze River, and the sediments and nutrients from Taiwan Strait to East China Sea is one third of the total. It has a great influence on the water mass exchanging and ecology of Taiwan coast and East China Sea.
The research focuses on the major constituents of tidal currents and the volume transport (VT) of the northern Taiwan Strait. Because the of data density previous studies is low in time and space in this region, lacking of long-term and a cross section of the strait actual measurement data, we installed a shipboard ADCP on the TaiMa Ferry that navigates between Keelung and Matsu to measure and to gather along track current velocity data. We obtain 160~280 data sets in different grids after screening sixteen months, and then use Harmonic Analysis to find out along-track tidal amplitude and phase of M2, S2, K1, O1 constituents.
The result from Harmonic Analysis showed that M2 is the major constituent and its energy is more than S2, K1 and O1 in our study area. Owing to the low and discontinuous sampling frequency on the fixed station, we can’t distinguish constituents that have similar period and low energy. For example, the relation between Harmonic Analysis result and OSU tidal model (TPXO) result of M2 reach 0.9 shows that most tidal current can be filtered. On the other hand, S2 is affected by M2, K1 and O1 still can’t be filtered correctly due to longer period and lower energy. To have 20% or less error on tidal current constituents, it requires data length of 3, 5 and 3 years for M2, S2 and K1 tides.
Use two different methods that TPXO and Harmonic Analysis to remove tidal contribution show 1~3 Sv VT through TWS and VT difference value of to- and return-cruises may be -1~1 Sv. The cause of the difference of VT between to- and return-cruises maybe the influence of wind, but it also implies the inaccuracy of remove tidal contribution. In addition, the northeast of the TS is located at the edge of the Keelung Valley and the east side of TS has a hollow and large variation on topography. This research also suggests the existence of baroclinic tide in these two regions, the associated tidal current amplitudes differ about 5~10 cm/s between upper and lower water level. It means that the result of Harmonic Analysis can never match the result of barotropic tidal model of TPXO.
| Identifer | oai:union.ndltd.org:TW/098NTU05279009 |
| Date | January 2010 |
| Creators | Wei-Lin Tsai, 蔡維琳 |
| Contributors | 劉倬騰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
Page generated in 0.0161 seconds