摘要或動機

微孔珊瑚是優良的生物氣候記錄器，可準確記錄海水表面水溫、陸源沉積物通量和其他微量海水組成等，已成為熱帶氣候變遷研究的重要工具。然而，珊瑚成長速率則顯著受限於海水表溫影響（邱景星，1999）。太陽是地表能量最主要來源，其活動狀態能深遠掌控地球氣候變化，因此其週期性變動規律，已成為近期地球科學家探討環境變遷的重要資訊。 本研究以台灣東南外海綠島採集的微孔珊瑚骨骼樣本，藉由X-ray精確測量其年平均生長速率及觀察骨骼內微量腐殖酸螢光特性，並透過比對太陽輻射量、珊瑚生長與太陽黑子數目的相關性分析，以推倒百年來控制地表氣候變遷的主要因素。 本研究經由頻譜分析、主變量計算、平均標準差和太陽輻射角修正，獲得正確太陽黑子數目、地區性輻射、海水表面溫度和珊瑚生長速率等資料，並討論其間的相互關係。 結果顯示，太陽輻射、海水表面溫度和氣溫有高度正相關（r2>0.62），證實太陽對地球氣候系統的重要性。太陽黑子與輻射資料，則因大氣折射、日照時數等因素影響，正設法解決這些干擾效應；而珊瑚生長速率與海水表面溫度的相關性，則涉及雙極化效應（註）及其他未知因素影響，尚待進一步釐清。
（註）：雙極化效應指珊瑚在過高或過低的環境下，生長速率皆會停止 The skeleton of Porites corals is one of the most useful biogenic recorders, which provide relevant information of abrupt climate change, such as sea surface temperatures (SSTs), riverine sedimentary flux, and seawater compositional variations. Information retrieved from coral skeleton, therefore, has become a powerful tool for studying tropical climate change. The annual growth rate of Porites corals, however, was affected strongly by local SSTs (Chiu, 1999). On the other hand, the climatic condition on Earth surface is regulated significantly by solar activity. Subsequently any intensity or periodicity variation in sunspot activity will cause major global environmental changes. This research aims to study coral skeleton collected from the Orchid Island (Lan-yu) offshore southeastern Taiwan for precise measurement of annual growth rate using X-ray density bands, as well as the luminous characteristics of trace humic acids in skeleton. A systematic comparison among solar irradiation, SSTs and coral growth rate will provide critical information on major factors that may affect environmental changes occurred during the last millennium. In this study, we apply spectrum analyses, principal component, mean standard error method, and modified sun irradiation angle to correct biases presented in the available data of observed sunspot number, local irradiation, SSTs and coral annual growth rate and to examine possible relationships among these factors. We have found excellent correlation coefficient (r2>0.62) in solar irradiation, SSTs and air-temperature, which support the importance of solar irradiation to the earth surface climate. However, effects on cloud and length of sun irradiation need further investigation to emphasize the importance of sunspot activity to the annual growth rate of Porites corals. No straight forward relationships were observed between coral growth rate and local SSTs due to complicated biological effect (1*) or other unknown factors, waits for further investigation in the near future. 1* Complicated biological effect means that coral may stop growing their skeletons when the temperature it lives in is over range for growth.