從呂宋海峽產生的內波，在向西傳遞的同時，常被觀測到入侵東沙環礁海域，其造成的混合作用持續的時間和範圍，雖然沒有季風那麼大，對當地的生態環境仍然有顯著的影響。海水的上下混合推動營養鹽的交換，進而影響海表葉綠素的增生，表現在葉綠素的濃度和空間分布中，進而影響此區域的生態環境。
本研究利用2002年7月至2013年9月之衛星月平均葉綠素資料，觀測東沙海域周圍之葉綠素濃度之時間和空間上的變化，與南海無內波侵襲的區域比較。在空間上，東沙環礁周圍東面或北面，經常出現一團高濃度的葉綠素分布；南海無內波區則大致上呈現整體的一致性。時間序列中，東沙周圍海域的葉綠素濃度整體有高於南海無內波區的現象，但兩者皆有明顯的季節性變化；環礁的東北和西南方向兩相比較則沒有明顯差別。差異最大是夏季的時候，東沙環礁周圍可以看到明顯的高濃度葉綠素，無內波區則沒有，合理的推測為內波的影響，在本該是葉綠素濃度較低的夏季，因內波盛行帶來額外的高營養鹽及後續光合作用，葉綠素濃度最大值約為每立方米0.3毫克。此外在長時間尺度中發現，內波有助於抵抗ENSO所造成的葉綠素濃度下降，東沙下降幅度平均較無內波區減少5%。

Internal waves were reported frequently generated at Luzon Strait, propagated across northern South China Sea, and dissipated in the western continental shelf. The mixing of internal waves, although has smaller scale than that of monsoons, may enhance growth of chlorophyll concentration and associated ecosystem of the Dongsha Atoll region.
This study try to look at the spatiotemporal variations of chlorophyll concentration in the regions of with or without internal waves, applying monthly mean chlorophyll data of MODIS from July 2002 to September 2013. Results of data analysis showed that, spatially, abnormally high concentrations of chlorophyll were observed frequently at the east and north sides of the Dongsha Atoll. Temporally, there were seasonal variations of chlorophyll concentration in the regions of with or without internal waves. The region with internal waves, however, has a relatively higher value of chlorophyll concentration, especially in the summer season with peak value of 0.3 mg/m3. In the long-term trend, internal wave may slow down, approximate 5%, the decrease of chlorophyll due to ENSO.

摘要 iii
Abstract iv
圖目錄 vii
第一章、緒論 1
1.1 前言 1
1.2 文獻回顧 5
1.3 研究動機與目的 10
第二章、資料來源 11
2.1 MODIS衛星資料 11
2.2東沙氣象觀測站 14
2.3多重聖嬰指數--MEI 16
第三章、資料品質管理與分析方法 17
3.1 衛星資料品管與補遺 17
3.3 傅立葉轉換--FFT 21
3.2 經驗模態分離--EEMD 22
第四章、結果與討論 24
4.1 葉綠素之空間分布 24
4.1.1 橫跨南海之葉綠素分布 24
4.1.2 東沙環礁之葉綠素空間分布 26
4.1.3 南海無內波區之葉綠素空間分布 36
4.2風場的效應 46
4.3 葉綠素之時間變化 47
4.3.1 東沙環礁之葉綠素時間變化 48
4.3.2 南海無內波區之葉綠素時間變化 51
4.2.3 風場與葉綠素之時間序列FFT 53
4.3.4葉綠素、風場之時間序列EEMD與MEI 56
第五章、結論 62
第六章、參考文獻 64

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