近幾年來諸多學者投入內波研究，大多都是研究內波的物理特性及其對水團生態與化學之研究，但是鮮少人探討內波對於地質影響。以EK500與3.5KHz地層剖面儀觀測得知，南海陸棚緣海底底層水深600公尺有不少沙波地貌存在。而沙波成因可能為週期性的動力所致，內波為南海內部非常重要的動力機制，其運動對於海洋底床流場形成非穩態的擾動；為釐清內波是否為影響沙波形成的主因，本文進行一系列數值模擬研究。
現有的沙波生成研究大多都是以近岸地區為主，對於水深500公尺以下的沙波，因為觀測較為不易，少有專門性的討論。本文先以Korteweg de Vries (KdV) 方程式推導出孤立波流流場，再代入Regional Ocean Modeling System (ROMS) 數值模式，以模擬內波於三維空間的運動與其引致之懸浮物 (泥沙) 運動，藉以對沙坡堆形成機制進行探討，並分析沙波波長變化，最後再與實測資料作比較分析。
經模擬結果可得知，內波確實會造成沙波形成，經過多次的內波通過量後，平坦的底床會逐漸形成沙波地貌，而不同深度與坡度的地形會影響沙波波長 。

In the last few years, internal waves have been extensively studied by many scholars, mostly focused on the physical property and the effect on ecology and geochemistry. The geological influence, however, was rarely discussed. By EK500 and 3.5 kHz sub-bottom sonar system, it is reported that many sand waves exist in the South China Sea at 600 meter water depth. Internal waves are a very important driving mechanism in the South China Sea. Its movement over the marine bed causes unsteady flow field disturbance. In order to clarify whether the internal wave is the main factor to form sand wave, we conduct a series of numerical simulations.
Most studies on the formation of sand waves are mainly in the nearshore area. Due to the difficulty in observation, only very few special discussions consider depth of 500 meters or deeper. First of all, in this thesis, we use the Korteweg de Vries (KdV) equation to derive wave and current in an internal soliton. Then, the flow field is substituted into the Regional Ocean Modeling System (ROMS) numerical model to simulate the three-dimensional movement of internal waves and the associated movement of suspended sediment in order to discuss the mechanism of sand wave formation. Finally, the variation of wavelengths of sand wave is analyzed and compared with in-situ measurement.
From the simulation result, the internal wave causes the formation of sand waves. After the passage of dozens of internal waves, a flat sea floor will gradually form sand wave topography. Different depth and slope of the sea bottom will affect the sand wave wavelength also.

中文摘要 ……………………………………………………………………………i
英文摘要……………………………………………………………………………ii
目 錄………………………………………………………………………………iii
圖目錄………………………………………………………………………………iv
表目錄 .……………………………………………………………………………vi
第一章 緒 論.……………………………………………………………………… 1
1-1 內波與KdV 方程簡介.……………………………………………… 1
1-2 沙波與泥沙起動的簡介……………………………………………… 2
1-3 研究目的……………………………………………………………… 4
1-4 文獻回顧……………………………………………………………… 5
1-5 研究區域介紹 ……………………………………………………… 9
1-6 東沙環礁鄰近沙波初步探討………………………………………… 10
第二章 數值模式. ………………………………………………………………… 16
2-1 模式簡介. …………………………………………………………… 16
2-2 模式初始場與邊界條件設定. ……………………………………… 19
2-3 底床沉積層設定……………………………………………………… 25
2-4 臨界剪應力計算……………………………………………………… 27
2-5 底床地形變更流程…………………………………………………… 29
第三章 模式模擬與驗證. ………………………………………………………… 30
3-1 驗証方法……………………………………………………………… 31
3-1-1 沙波平均波長、波高定義方式………………………………… 31
3-1-2 FFT 頻譜分析 ……………………………………………………32
3-2 內波通過時底層變化情形 … ……………………………………… 32
3-2-1 內波通過時懸浮載與底床載起動……………………………… 32
3-2-2 內波通過時底床沉積層時間變化……………………………… 33
3-2-3 內波通過成熟沙波模擬………………………………………… 35
3-3 沙波尺度模擬與驗證 … …………………………………………… 39
3-3-1 模擬區域分段簡介……………………………………………… 39
3-3-2 區域A 分段簡化地形模擬與網格驗証 ……………………… 40
3-3-3 區域B 分段簡化地形模擬與比較……………………………… 51
3-3-4 全區域模式模擬與比較………………………………………… 63
3-4 縮小尺度模擬 ……………………………………………………… 78
3-5 平均流模式模擬……………………………………………………… 84
3-6 不同粒徑大小比較…………………………………………………… 85
3-7 內波通過現有沙波的地形模擬……………………………………… 87
第四章 結論 … …………………………………………………………………… 89
參考文獻 … ……………………………………………………………………… 90
附錄A、粒徑分類列表 …………………………………………………………… 94
附錄B、ROMS 模式簡介……………………………………………………………95

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