Rivers are conduit that transport terrestrial matters to the ocean. Studying how the composition and transport mechanism of terrestrial matters influenced by tide, wave, wind and discharge is an important issue in the disparate of river-sea systems. The aim of this study is to understand the temporal and spatial variability of the grain size distribution of a river plume, using EOF (Empirical Orthogonal Function) to analyze the correlation between environmental processes and suspended sediments.
We used CTD and LISST-100 to collect upper-colum profile data at Gaoping River mouth in five (R/V Ocean Research III) cruises from 2005 to 2009. We also deployed an instrumented tetrapods and a moored buoy at the inner Gaoping River mouth and the inner continental shelf off Gaoping River mouth for two days, respectively. In all the upper-column data, the volume concentration increased in surface column when the salinity decreased. The variability of volume concentration are dominant in grain sizes between 10-250 £gm.
We used EOF to analyz the time series to investigate the correlations among the volume concentration of 5 grain-size groups (<3, 3-10, 10-63, 63-153, and 153-250 £gm), salinity, water temperature, and alongshore and across-shore winds. The first eigenmode explains about 50 % of the total correlations. This mode describes the dominant influence of the river runoff that affected all the grain-size classes within the plume. This mode suggests that the grain-sizes between 3-250 £gm are of terrestrial origin (low salinity, high water temperature) exported during the ebbing tide.
The second eigenmode accounts for about 20 % of the total correlations. This mode describes the dominant influence of the wind.
When under the upwelling-favorable across-shore wind, the upwelling brings low temperature and clay-sized suspended sediment from the submarine canyon to the surface. The results suggest that the size-classes greater than 3 £gm are terrestrial suspended sediment and transported by the river plume, the size-classes finer than 3 £gm are mostly from the submarine canyon by the upwelling-favorable winds.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0206110-115302 |
| Date | 06 February 2010 |
| Creators | Yang, Jen-kai |
| Contributors | James T Liu, Saulwood Lin, Yu-Huai Wang, Sen Jan |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0206110-115302 |
| Rights | unrestricted, Copyright information available at source archive |
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