| Summary: | 碩士 === 國立臺灣海洋大學 === 海洋環境資訊學系 === 94 === The purpose of this study is using an existing three-dimensional model, Princeton Ocean Model (POM), to simulate the modulation of the Chang- jiang River plume (CRP) by tides in the East China Sea. The model utilizes realistic bathymetry and coastal geometry. The bottom topography of the study area is obtained from ETOPO5.
In this study, a set of experiments have been designed to investigate the structure of the CRP. First, the model is just driven by tides from the open boundaries. The sea level heights are derived from the NAO99b dataset. In addition, the model result is compared with observed data of five tide stations: Nazha, Keelung, Zhejiang, Jiangsu, and Dalian. It is found that the model is reasonably consistent with observed data except that at the Dalian station. We think that the error probably is caused by the inaccuracy of bottom topography or the deformation of the model mesh grids.
Secondly, the model simulation includes river inflow and tides. In order to distinguish the influence of tides on the CRP, we have run a case with river discharge only. The model results show that if the experiment is done with tides, the coastal jet in the southern river mouth becomes weaker and the anticyclonic vortex to the north is also reduced. Therefore, the CRP is significantly influenced by tides. The plume in the meridional direction is reduced but in the zonal direction is expanded.
Finally, the vertical features of two sections of the CRP in a one-day tidal cycle have been discussed. The model shows that an intrusion phenomenon occurs due to the variation of bottom topography and tides. The river plume oscillates near the outer Changjiang mouth and has a tendency of intrusion.
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