碩士 / 國立臺灣大學 / 地理環境資源學研究所 / 92 / Coastal areas lie where the ocean meets the land. The landform change is quite fast and contains lot of influential elements. At the same time, the change of the coastal line will affect the distribution of coastal sand dunes. Thus, the coastal sand dunes have become one of the significant guidelines of coastal changes. This research is to explore the long-term transformation of coastal form and the distribution of coastal sand dunes of Taoyuan County, by using landscape contrasts (1904─2001) and basic pictures (1978─1994) in different periods of time, as well as GIS interior analysis of overlay. A one-year field observation is also set up. A sample line is established along Tsaoto coastal sand dunes, and the height of coastal landform is measured and the sand sample is collected every month. In this way, we are able to investigate the short-term seasonal transformation in the profile height of coastal land form, and explore the short-term variation of the distribution of sand beaches and the grain size of sand dune sediments, in order to analyze the transformation of Taoyuan coastal landform in terms of different time and space.
According to the GIS technique and the overlay analysis in landform map ,the greatest transformation occurred in the Lao-chieh Stream-Ta-chueh Stream Coast（the Tsaoto Coast）, during 1904─2001. The coastal line was in erosion and shrank backwards by 20-280 meters. And because of this, the sand dunes along this coast shrank backwards by 30-160 meters during 1978─1994.
On the other hand, the field observation shows ：(1) The profile height of Tsaoto Coast rises in autumn, falls in winter, slowly rises in spring and rises again in summer. This short-term variation cycle is mainly caused by the water power , the wind and the relative rise and fall of sea level in their seasonal changes . (2) As for the beaches and sand dune sediments distinguished by the sea level per month, there are obvious variation (α= 0.05) in the distribution of grain size, in terms of time, median, sorting coefficient, and kurtosis in different months and different landforms. But skewness is influenced by months only, and there is no obvious variation in beaches and sand dunes.( α=0.05) (3) As for the sediments of grain size distribution in the coast and the sand dune, the median comes between 1.67φand 2.2φ, while sand dunes have higher median than beach sand. This suggests the grain size of sand dunes is smaller, while that of beach sand is bigger. The sorting coefficient of beach sand is higher than sand dunes, which suggests the sorting coefficient of wind effect is better than that of water effect. As for the variation in skewness, the grain size composition of beach sand is less regular, while that of sand dunes is much more regular. The grain size kurtosis of sand dunes is higher than that of beach sand, and this shows that the grain size distribution of sand dunes is more centered.
| Identifer | oai:union.ndltd.org:TW/092NTU00136005 |
| Date | January 2004 |
| Creators | Yang, Mei-ping, 楊美萍 |
| Contributors | Li, Chien-tang, 李建堂 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
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