碩士 / 國立中山大學 / 海洋地質及化學研究所 / 87 / and government officials are concerned. The aim of this study is to understand the hydrodynamics of the Tseng-wen river plume during the flood season in June. First, we deployed an instrumented tripod at Tseng-wen river mouth to observe wave, tide, currents, temperature, salinity, and turbidity for about one week. And cross-shore and longshore transects were surveyed by measuring the vertical salinity, temperature, and suspended sediments concentration (SSC). Besides, numerical modeling study was also involved. Princeton Ocean Model (POM) was applied to simulate Tseng-wen river plume.
The observed current data are dominated by semi-diurnal tides. The stratified river plume moves north and south along the coastal shore according to tidal current. It moves northward in flood tide and southward in ebb tide. The range of the plume is farther off-shore when tidal current starts to change direction. According to the cross-correlation analysis, wave is the most important factor that influence SSC. The second is the river plume. That means the influence of wave resuspension is the greatest.
Numerical simulation and model visualization help us to understand the distribution and temporally change of the river plume. In the modeling result, the river plume swings north-west and south-east in a tidal cycle. It moves north-west in flood tide, and then switch to south-east in ebb tide. In general climate condition, it is a hypopycnal plume. The output river flow is above the reverse saline in-flow. These two currents converge at river plume front. Different grain sizes of sediments have different distributions. 190, 63 micro-meter of sediment grains settle down to bottom before reaching the river mouth. Some sediments are resuspended in ebb tide and settle rapidly in flood tide. 0.5 micro-meter grains has extremely high SSC because of low threshold and unlimited supply from the sea floor. The plume of 0.5 micro-meter grains is hyperpycnal plume.
The simulated currents are very close to observed time series data. The observed salinity profile is more stratified than model results. Because this model cannot treat the sediments resuspension by wave, the simulated sediment concentration time series only react to tidal changes.
| Identifer | oai:union.ndltd.org:TW/087NSYSU271006 |
| Date | January 1999 |
| Creators | Ray T. Hsu, 許敦睿 |
| Contributors | James T. Liu, 劉祖乾 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
Page generated in 0.0018 seconds