南海內波之音傳效應是過去十年來國際上水下聲學研究相當重要的議題之一，在呂宋海峽形成的大尺度內波，向西傳遞數百公里後，因內波淺化作用，在東沙環礁陸棚海域慢慢變型並破碎消散。過去南海內波之音傳效應研究大多停留在北南海陸棚與陸坡上，尚未有資源投入研究東沙環礁附近之音傳特性。
　　東沙環礁海域由於其特殊的地理環境與位置，加上有不同類型內波的存在，成為了相當熱門的軍事與科學研究地點。東沙海域地形坡度較陡，海域深度變化劇烈，內波在此海域快速變形、破碎、轉向，且有不同方向內波在此海域傳遞，形成複雜的聲納操作環境。本研究為了解東沙環礁海域地形以及淺海內波對聲波傳遞的影響，與美國華盛頓大學應用物理實驗室(APL)和木洞海洋研究中心(WHOI)合作，在2016年5月於東沙環礁海域進行實海域的內波探測實驗，並於實驗區域內佈放三串聲學資料接收錨碇串，以及一串水文資料接收錨碇串，再以中山大學自製拖曳式中低頻聲納系統進行主動聲源訊號拍發與被動接收，得到實海域的地形探測以及音傳實驗結果，並經由此實驗結果來比較同樣地形變化下，內波所造成聲波傳遞的能量變化，以及內波存在與否，對多路徑效應(Multi-path effect)、都卜勒效應(Doppler effect)、訊雜比(Signal-to-noise ratio)、聲壓位準(Sound Pressure Level)的影響，另輔以拋物線方程法(RAM-PE)進行模擬，來驗證比對實驗結果之二維及三維內波音傳效應，並探討不同聲源深度下之模擬傳輸損耗受內波影響之變化，最後再討論不同傳遞方向下之模擬傳輸損耗所計算獲得之聲納聲景。本研究的結果可用於討論在近海內波存在的海域下進行音傳實驗及聲學通道的影響，並可作為日後東沙環礁海域水下聲波傳遞與通訊發展之依據。

Huge internal solitary waves (ISW) and steep bathymetry around DongSha Atoll in the South China Sea was expected to affect sound propagation. Internal waves, generated from the Luzon Strait due to spring tide and neap tide propagate cross the basin area and hit the east wage of Atoll. In 2016, an acoustic experiment was conducted around the atoll by deploying three acoustic and one environmental moorings for learning the channel for both mid and low frequency signals, transmitted by an integrated sonar system. The paper is aimed to study channel-estimation of passband/baseband signals using pulse compression technique and surface ambiguity function to correct the Doppler Effect. Water column perturbed by environmental parameters such as sound speed, temporal variance, sediment property and bathymetries are aimed, and its impaction to channel passband/baseband response is also studied in this paper. Furthermore, parabolic equation was also used in this paper to study two- and three- dimensional acoustic wave transmission modeling. And also discuss how internal waves affect sound propagation and acoustic energy with acoustic sources in different water layer.

目錄
論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖次 vii
表次 xii
第一章 緒論 1
1.1 研究背景 1
1.2 研究目的與研究方法 5
1.3 文獻回顧 6
1.3.1 內波研究 6
1.3.2 聲學研究 9
1.4 論文架構 16
第二章 東沙環礁聲學實驗 17
2.1 實驗地點與流程 17
2.1.1 二維音傳實驗 19
2.1.2 三維音傳實驗 19
2.1.3 空間變動音傳實驗 19
2.2 實驗儀器與配置 26
2.2.1 資料紀錄錨碇串 26
2.2.2 拖曳式聲納系統 36
2.3 音傳實驗訊號 39
第三章 實驗資料處理與分析 42
3.1 脈衝壓縮(Pulse Compression) 43
3.1.1 解調(Demodulation) 44
3.1.2 濾波(Filter) 46
3.1.3 相關性積分(Auto-correlation) 48
3.2 都卜勒效應(Doppler effect) 49
3.3 聲壓位準(Sound Pressure Level)與均方根壓(Root-Mean-Square) 50
3.4 聲學通道分析 52
3.4.1 聲速剖面分析 52
3.4.2 通道脈衝響應 54
第四章 數值模擬 58
4.1 聲學模組理論 58
4.2 數值模式RAM-PE 59
4.3 移動平均(Moving Average) 60
4.4 模擬參數設定 61
4.5 模擬結果分析 65
4.5.1 模擬資料驗證 65
4.5.2 聲壓位準與音傳損耗模擬 69
4.6 延伸模擬分析 81
第五章 結論與討論 94
參考文獻 98

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