在海洋中進行通訊或偵測時，聲納系統是傳遞訊號的主要具，其中海洋環境噪音(Ocean Ambient Noise)為其重要的參數之一，且由許多複雜的機制所組成，如風雨、生物及船舶等聲源，因此需從各種不同角度來分析，才能真正掌握其複雜的特性，達到提升聲納效能預估的作用。本文以臺灣東南與東北海域為研究範圍，於2012年夏季同時段所量測的聲學資料進行分析與比較，來探討風浪和降雨在相同時間內分別對兩海域環境噪音所造成的差異，並繪製頻譜來比較兩海域在不同海況下的風浪與降雨，對不同頻率環境噪音所提升的位準，最後利用能量計算的方式，區分風浪和降雨在高頻(>0.5k Hz)環境噪音的貢獻量。此外，將兩海域所量測的聲學資料與風速資料，藉由殘差分析(Residual Analysis)來替資料做前處理的動作，使資料能夠滿足線性迴歸假設條件，以進行迴歸分析來推導出風浪噪音預估公式，最後將公式帶入風速資料比較環境噪音實測值與預估值，驗證其預估公式準確程度。從時頻譜初步分析結果顯示，低頻(<0.5k Hz)環境噪音出現週期性峰值，噪音位準大約每24或12小時提高10~15 dB，初步假設是由潮汐所導致，因此進行時序分析來觀察其週期時間，並配合水文資料與文獻來佐證其潮汐為此現象之噪音源。

When communications or detection in the ocean, sonar system is the main tool for signal transmission and ocean ambient noise is one of the important parameters in it. Ocean ambient noise includes various and diverse sources like wind, rain, marine life, ship, and etc. Using different ways to analyze are needed to understand the complicated properties of ocean ambient noise, therefore sonar system performance prediction can be improved significantly. In this study , the ocean ambient noise data were collected in summer of 2012 at Taiwan southeastern and northeastern seas, then analyzed and compared the characteristics and divergence of wind-wave and rain- generated noises of same period , and plot wind-wave and rain- generated spectrum to compare noise level in different frequency and sea states at different seas. Finally, calculated the high frequency(>0.5 kHz) noise energy budgets of wind-wave and rain generated. Furthermore, using residual analysis to select good data of noise and wind speed before data processing, when the good data meet the assumptions of linear regression, then the wind-wave noise prediction equations from can be obtained. The estimation and measurement of noise level were compared to verify the equations are accurate. In low frequency (<0.5 kHz), ambient noise has periodic peak shown in spectrum, the noise level increases 10 to 15 dB every 24 hours. By using sea level and temperature data, the periodic fluctuation of low frequency sound level is proved to be related to the tidal current.

論文審定書....................................................i
謝誌.............................................................iii
摘要.............................................................iv Abstract........................................................v
表次.............................................................ix
圖.................................................................xi
第一章 緒論 1
1.1 研究背景 1
1.2 海洋環境噪音 3
1.2.1 風浪噪音 5
1.2.2 降雨噪音 8
1.2.3 潮汐噪音 10
1.3 研究目的 11
1.4 論文架構 12
第二章 實驗方法 13
2.1 實驗儀器 13
2.1.1 聲學記錄儀器 13
2.1.2 氣象記錄儀器 16
2.2 聲學資料 18
2.3 氣象資料 20
2.3.1 風速資料 20
2.3.2 降雨資料 21
2.3.3 潮位資料 22
2.4 資料分析流程 23
第三章 相關理論 24
3.1 訊號處理方法 24
3.1.1 取樣定理 24
3.1.2 快速傅立葉轉換 25
3.1.3 移動平均 26
3.2 統計理論 27
3.2.1 相關係數 27
3.2.2 常態分佈與Kolmogorov-Smirov檢定 28
3.2.3 線性迴歸分析 30
3.3 殘差分析 31
3.4 聲壓與聲強計算 33
第四章 結果與討論 35
4.1 時頻與統計分析比較 35
4.1.1 環境噪音時頻譜 35
4.1.2 環境噪音位準統計與分佈機率 37
4.2 風浪噪音分析 41
4.2.1 環境噪音與風速資料之時序分析 41
4.2.2 風速資料統計 43
4.2.3 風浪噪音頻譜 45
4.3 風浪噪音預估之迴歸結果 48
4.3.1 風浪噪音預估之迴歸假設 48
4.3.2 風浪噪音預估之迴歸分析 49
4.4 降雨噪音分析 54
4.4.1 環境噪音與降雨資料之時序分析 54
4.4.2 降雨資料統計 55
4.4.3 降雨噪音頻譜 57
4.4.4 降雨噪音預估之迴歸假設 61
4.4.5 降雨與風浪噪音之能量貢獻 62
4.5 低頻環境噪音與潮汐週期 64
4.5.1 低頻環境噪音之時頻分析 64
4.5.2 低頻環境噪音與水文資料分析 69
第五章 結論與建議 71
5.1 結論 71
5.2 建議 73
參考文獻 74

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