碩士 / 國立臺灣海洋大學 / 應用地球科學研究所 / 98 / The Haifong Island is a barrier island located slightly off the southwest side of the coast in Yunlin County, Taiwan, trending approximately parallel with the shoreline on a north-northeast-to-south-southwest axis, at 15.19 kilometers in length. It is composed of two sections, namely the southern and the northern parts of the island, which are referred to as South Haifong Barrier Island and North Haifong Barrier Island, respectively.
According to relevant studies up to 2000, it is observed that the island exhibits several phenomena, including southward drift, breaking up, landward rollover, and decrease in surface area. Barrier islands are very vulnerable, easily affected by natural causes and human intervention. Without the protection of barrier islands, shorelines will be directly attacked by waves, which exerts significant influence on the coast of Yunlin. Therefore, it is of immediate importance to continuously observe the follow-up shifts of the island since 2000.
In response to the aforementioned phenomena, this study seeks to observe and analyze data gathered from the French SPOT satellite images procured in 2001, 2003, 2005 and 2007, using the Image Digitizer software to delineate the shoreline, followed by juxtaposing the satellite images for analysis, observing the changes in the location of the geographic central point and the breaker line on the seaward side of the island, lastly followed by a surface area analysis using the Map Digitizer software. Also, this study seeks to understand how short-term and sudden factors such as typhoon affect changes in barrier islands, in addition to the trends in long-term changes such as morphology and shift in location.
The results in this observational study have shown that there are significant changes in the shape, location, and shift rate when compared to previous times. Moreover, the occurrence of typhoon events is observed to contribute to the southward lateral movement of the barrier island. Due to insufficiency in sand sources, the Haifong Barrier Island is observed to be more vulnerable to influence by environmental factors, in the period from 2001 to 2007. For instance, it exhibits the traits of breaking up caused by forces from tidal currents, southward drift resulting from strong waves in long-shore currents, landward rollover caused by repetitive attack from sea waves. These phenomena are in continuous correspondence to previous studies in the traits of gradual change. In consideration of facilitating local fishery, it is suggested that as the tidal inlet drifts beyond Potzuliao Harbor around 2010 to 2011, man-made means such as construction may be applied for the purpose of fixation or dredging under these circumstances. In addition, the nearby Jinhu area shall be protected first in the near future, yet the Haifong Barrier Island is observed to be under gradual, local landization as the result of landward rollover.
| Identifer | oai:union.ndltd.org:TW/098NTOU5135007 |
| Date | January 2010 |
| Creators | Fong-Yin Huang, 黃鳳吟 |
| Contributors | Eason Hong, 洪奕星 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 75 |
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