博士 / 國立臺灣大學 / 海洋研究所 / 93 / The current velocity profiles, bottom water temperature, and sea level were observed to study the spatial and temporal variations of the tidal and subtidal current in the Taiwan Strait from 1999 to 2000. Results indicate both diurnal and semidiurnal tidal currents were primarily barotropic. The barotropic diurnal tide might be explained by a single Kelvin wave propagating along the Mainland China coast from north to south. However, the barotropic semidiurnal tide manifested as a more complicated form in the Taiwan Strait.
In the northeast monsoon, the subtidal current generally fluctuated with the northeast winds. When the northeast wind was weak, the along- and cross-strait subtidal current flowed primarily against the wind and toward Taiwan, respectively. As the northeast wind intensified, the along-strait current flowed downwind, brought the cold China coastal water southward, and formed a baroclinic velocity front in the western portion of the Taiwan Strait. The Ekman effect forced the cross-strait current toward Mainland China in the upper water column. Nevertheless, the current in the lower water column remained toward Taiwan. From September 28 to December 14 of 1999, the along-strait volume transport, estimated from interpolated current velocity, varied from -5 to 2 Sv with a mean value of 0.12 �b 0.33 Sv. Similar transport was also estimated from the sea level difference across the Taiwan Strait. However, the difference between two estimates is non-negligible
In the southwest monsoon, the subtidal current was stable with the along- and cross-strait subtidal current were northward and toward Taiwan, respectively. The large northward subtidal current generally occurred at the central and western Taiwan Strait. Temperature front was found in the eastern Taiwan Strait. During the transition of monsoon, both the wind and current velocities had large fluctuations. Such fluctuations were gradually reduced when the monsoon gained its full strength.
Although the local wind played a dominant role for the fluctuations of current velocity and transport in the Taiwan Strait, it was not the only factor. The remote impacts on the current velocity variation from the north and south could be also important in the Taiwan Strait.
| Identifer | oai:union.ndltd.org:TW/093NTU05274002 |
| Date | January 2005 |
| Creators | Sheng Fong Lin, 林勝豐 |
| Contributors | Tswen-Yung Tang, 唐存勇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 181 |
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