學位論文

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Start date: 2002End date: 2009

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    班達海域過去25 萬年以來表層海水營養鹽利用率之重建： MD012380 岩芯之氮同位素紀錄
    (2004) 黃瓊儀
    海洋生物生產力是海洋調控二氧化碳濃度變動的主要參數之一，而氮營養鹽（主要為NO3－）是初級生產者進行光合作用合成本身有機體必須的物質之一，因此其含量的供需狀況是控制初級生產力多寡的重要控因之一。表層海水營養鹽的含量及生產者的多寡會影響營養鹽被利用的程度，而此不同的結果會反映在氮的同位素組成的分化效應上。因此，本論文工作是希望藉由分析沈積物中氮同位素值記錄隨時間的變化來重建班達海域古海洋表水氮營養鹽的利用率及其隨古環境 與古氣候變遷的訊息。 本論文研究乃利用法國海洋研究船瑪麗安·杜帆（Marion Dufresne）號於2001年夏天執行國際海洋古全球變遷計劃（IMAGES）第七航次時，在屬西太平洋邊緣海之班達海（Banda Sea）所採集的MD012380 岩芯進行分析研究工作。分析工作包含此岩芯的氮同位素（δ15N）值，沈積物之總有機碳組成（TOC）、總有機碳/總氮比值（Corg/N atomic ratio）及有機碳的碳同位素（δ13C）組成等。其中氮與 碳元素與同位素的分析方法主要是採取燃燒法（combustion method），將沈積物經高溫燃燒後所釋放出的氣體（N2、CO2）收集後以質譜儀及元素分析儀進行其同位素值與C、N 含量的測定。分析的標本因受限於氧同素所建立的時間架構，故只以自本岩芯頂部至2082 公分（氧同位素定年結果為250ka）以來的結果作討論。 此部份的分析資料相當於MIS7 與8 交界（250ka）以來的最近三次冰期-間冰期的變遷。 MD012380 岩芯之氮同位素分析結果落於5.24~8.81‰之間，在暖期之MIS1氮同位素值平均約為7.51‰，MIS5 除了73ka 出現較低的氮同位素值（5.24‰）外，其餘平均約為6.92‰，到了冷期的MIS2 為6.31‰、MIS3 為6.63‰、MIS4 則為6.63‰，整體的氮同位素值變化可看到冷期低-暖期高的趨勢，但在MIS6 及7 則有約2‰的震盪，且無法區隔MIS6 與7 之間的變動差異。利用本岩芯所在的海域之現今水文資料、岩芯本身氮同位素組成與總氮含量的關係及其與總有機碳隨時間變動的趨勢，再加上岩芯中有機氮相對於有機碳比值及碳同位素組成，推斷本岩芯所紀錄的氮同位素組成並不具有固氮作用的訊號，且可排除成岩作用及脫硝作用的影響，而其中有機物的來源屬於海源的特徵。因此，MD012380 岩芯的碳、氮同位素組成的結果應可反映班達海域表層水的同位素分化的效應。 所以，本研究利用拉雷分化效應公式可計算粗估班達海域之古海洋環境中表層水營養鹽利用率及其隨時間的變動趨勢。估算的結果反映出在冷期時班達海地區的浮游植物對營養鹽的利用率較低而暖期較高。再配合代表生產力變動的總有機碳含量結果發現MD012380 岩芯沈積物在冷期時總有機碳含量較高但δ15N 較輕；相反地，暖期的總有機碳含量較低且δ15N 較重，這些指標反映在冷期時有較高的生產力，且氮營養鹽的利用率較低。由此推測岩芯中冷期-暖期變化的氮同位 素組成應非生物生產力變動而造成其對營養鹽攝取量的不足，而應是營養鹽供應量在冷期時有明顯的增加所造成的結果。而此較多營養鹽的供輸極可能是因班達海地區於冷期時因季風強度的改變使表水有較明顯的湧昇流強度增強的效應而導致營養鹽由深層水的供應量增加，因此使得浮游植物對硝酸根離子的利用率變低的結果。
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    線上課程對高二學生四季成因概念學習的影響
    (2003) 曾永祥
    本研究以概念改變（conceptual change）理論為基礎，結合電腦模擬（computer simulation）教學策略，發展一套四季成因線上課程，探討高二學生在課程進行前所具有的四季成因另有概念和課程結束後的學習成效與概念改變情形，並分析學生的空間能力對其四季成因概念學習的影響，最後歸納學生對此線上課程的綜合意見，以做為未來發展地球科學相關網路教學課程的參考。研究對象為台北縣某國立高中兩班高二第一類組選修地球科學的學生，有效樣本共76人。研究工具包括四季成因線上課程、空間能力測驗、課程回饋問卷與四季概念診斷測驗、概念圖及半結構式晤談三種四季成因診斷工具。資料分析方法在量的方面採用t考驗（t-test）、卡方分析（χ2 analysis）、單因子共變數分析（ANCOVA）與線性迴歸分析（linear regression）；在質的方面採用內容分析及概念圖的歸類和評分。主要的研究結果如下： 一、高二學生在進行課程之前，對四季成因普遍具有另有概念，有些另有概念類型是文獻中未曾出現過的，可能來源是直覺經驗或教科書的誤導。 二、學生在完成課程之後，在概念圖與四季成因診斷測驗得分有顯著進步，所具有的另有概念類型也普遍減少，顯示四季成因線上課程可以幫助學生學習四季成因概念，並達到概念改變的目的。另外，學生的空間能力測驗得分會影響其概念圖後測得分，也就是學生在四季成因線上課程的學習成效，和本身空間能力有很大的關係。 三、對四季成因線上課程的學習觀感，大多數學生認為本課程的模擬動畫不僅能引起學習動機，更可以將文字難以表達的抽象概念具體呈現，並藉由操弄動畫的過程探索四季成因概念。 四、本研究的課程提供互動式的線上學習環境，提供了多元化的教學方式，讓學生主動建構四季成因概念。然而研究結果顯示，學生在缺乏教師引導的情況下，會誤解課程動畫所呈現的概念內容，造成概念的混淆。因此，如果能夠在課程進行過程加入老師的引導，可以減少學生在學習過程產生的迷思。
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    地磁複變解調與地震活動之相關性:以台灣崙坪全磁力資料為例
    (2003) 何英銳
    複變解調方法(complex demodulation method)係利用傅力葉轉換(Fourier Transform)在頻率域中作資料的頻率平移及濾波的技巧，可以取得時間序列中單一頻率分量的振幅(amplitude)及相位(phase)曲線。本研究利用複變解調方法檢視崙坪(LP)1993-1996、1999年及澳洲Alice Springs (ASP) 1996、1997、1999、2000年的地磁全磁力資料，由波譜發現明顯存在1、2、及3 cycle/day等峰值，利用複變解調分別求出其振幅隨時間的變化曲線(振幅時間函數)，其振幅值介於0 - 12γ之間。這些曲線皆有週期約為一年的季節變化，各地區、各頻率分量的季節變化皆不相同，有區域性差異。 將崙坪觀測站地磁全磁力波譜頻率分量的長期振幅曲線減去平均季節效應後，比對該測站100公里內的地震活動，發現其間有明顯的相關性存在，地震活動度高時1 cycle/day頻率分量振幅為低值，而且當振幅值由大轉小時為危險期，30至90天之內為大地震活動的高峰期，大地震發生時1 cycle/day頻率分量的去季節效應長週期振幅下降幅度皆超過1γ。
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    台灣地形對冬季冷鋒個案影之數值研究
    (2003) 林勝峯
    本文使用MM5 模式針對1996 年1 月7 日至9 日的冬季冷鋒個案 進行數值模擬，以探討台灣地形對冬季冷鋒之影響。該冷鋒呈東北 東—西南西走向之淺鋒面結構，在1 月7 日2200UTC 以後抵達台灣， 導致溫度驟降，形成寒潮爆發。衛星雲圖及地面的觀測均顯示該鋒面 受台灣地形阻擋，造成在東西部鋒面的強度及移動速度上出現差異。 地面觀測顯示鋒面在西岸自梧棲以南逐漸減弱並且移速減慢，東部則 較能維持原來之鋒面結構。鋒面出海後受到洋面之地表通量影響而產 生變性，使鋒後低層呈現濕冷的環境，在抵達台灣之後受地形阻擋的 抬昇作用影響，北部迎風面以及東部沿岸出現零星的降雨；而台灣西 南部在鋒面通過期間並沒有雲冪及降雨現象的發生。 中尺度模式MM5 的模擬結果顯示，通過台灣東西部之鋒面受地形 影響的機制並不相同。跨越大陸武夷山之鋒前氣流受台灣地形阻擋而 轉為北風，造成台灣在西南部及海峽上鋒前北風提前增強的現象。其 次，台灣西南部地表受日間輻射增溫的影響，使得鋒面之結構變得不 顯著且移速減慢，但海峽處之鋒面則受管道效應影響而加速南移。在 東部沿海由於冷空氣受地形阻擋而形成高壓脊，加強了花蓮沿海之非 地轉北風的強度，並造成鋒面在蘇澳以南加速南移。 以台灣地形及地表通量為變因所進行的敏感度測試中，顯示在沒有中央山脈的阻擋下，通過台灣本島之鋒面結構較為完整。並且鋒後 之風場並未出現受地形增強的現象，鋒面的移動速度則隨著鋒面南移 而減慢。而在無地表通量的模擬中，鋒面的溫度梯度並未受到暖洋面 的影響而減弱，因此在低層具有較強的壓力梯度與水平風切，顯示出 較強且淺的鋒面結構。而鋒後更穩定之環境則減弱了對流的強度並使 鋒後降水強度明顯減弱，可見地表通量在冬季冷鋒出海之後對鋒面結 構之修正扮演極為重要的角色。
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    南海與呂宋海峽渦漩動力之研究
    (2009) 許瑋真
    Satellite observations have shown the abundance of generally westward-propagating eddies in the subtropical regions in the North Pacific Ocean, especially north of 10°N. Eddies transport mass, and can significantly impact the circulation as well as the heat, salt and nutrient balances of the western Pacific marginal seas. This study uses a numerical model to examine the conditions when eddies can or cannot freely propagate westward through the Luzon Strait into the South China Sea (SCS). Composite analyses on the 10-year model data show that the fates of eddies depend on the strength and path of the Kuroshio. In one path which exists mostly during fall and winter, the Kuroshio loops westward into the SCS, the potential vorticity (PV) across the current is weak, and eddies are likely to propagate freely through the Luzon Strait. In another path which exists mostly during spring and summer, the Kuroshio tends to leap directly northward bypassing the SCS, the PV across it strengthens, and eddies are then blocked and are constrained to also follow the northward path. Nonlinear eddy-current interaction and the existence of a cyclone north of the Luzon Island during the looping phase explain why eddies of both signs can pass through the strait. It is shown also that the upstream state of the Kuroshio in the western tropical Pacific plays an important role in dictating the different paths of the Kuroshio. The looping (leaping) path is caused by a weakened (stronger) Kuroshio transport related to the northward (southward) shift of the North Equatorial Current in wintertime (summertime). During El Niño/Southern Oscillation (ENSO) events, the Kuroshio weakens and a large portion of the Philippine Sea water passes through the Luzon Strait. The intensity of the Kuroshio is capable of influencing the seasonal upwelling in the SCS. Seasonal upwelling events along the east coast of Vietnam and west coast of Luzon have been demonstrated by satellite data. In a normal year, a strong eastward jet is associated with the cooling and upwelling off Vietnam. Strong ENSO events have been recorded in the years 1997 and 1998: the satellite data clearly show a vigorous upwelling off Vietnam in August 1997, but a wan one in August 1998. Abnormal warming interrupts the normal upwelling generated off Vietnam and Luzon. Two defined indicators of sea surface temperature anomaly (SSTA), the upwelling off the coast of East Vietnam in summer and off the coast of west Luzon Island, reveal seasonal upwelling activities. Both these upwellings appear in normal years, but they diminish during the active warming period. The seasonal upwelling dynamics is dependent on ENSO and is also coherent with the South Eastern Tropical Indian Ocean (SETIO). The intensity of prevailing monsoon varies the proportion of the response to oceanic circulation and heat content, that is, weak monsoons do not promote water in vertical motion and less heat is released. The ocean heat content anomaly (OHCA) indicates whether the budgets for both the ascending and descending heat content are initiated at the western boundary. Although the OHCA in conjunction with the vortex has not been directly reported, the results of model dynamics studies are favorably comparable with the satellite data. Large-scale Indian-Pacific Ocean meteorological variations have certain strong impacts on the SCS. The teleconnection between ocean and atmosphere shows that the seasonal upwelling is controlled by the complex interplay between the internal and external sea-air interacting processes. The regional monsoon system changes rapidly in response to oceanic variations. The weak wind stress curl during the evolution of the La Niña cycle of 1998 affects the atmosphere-ocean coupling and hampers the generation of the upwelling. Variations in both the large-scale air-sea interaction and the strength of the Kuroshio transport impact (1) the generation of vortices over the SCS and (2) the path of movement vortices in the Luzon Strait.
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    以巢狀概念模式探究高中生之科學學習–科學認識觀、後設認知知覺、科學學習概念及其科學評量概念
    (2009) 李旻憲; Min-Hsien Lee
    The purpose of this study was to deeply investigate students’ nested ecology regarding science learning from multidimensional perspectives (i.e., the interrelations among scientific epistemological beliefs, metacognition, conceptions of learning science, and conceptions of science assessment). To this end, this study performed the quantitative method to initially explore the interrelations among scientific epistemological beliefs, metacognitive awareness, and conceptions of learning science. Then, the qualitative method was conducted to deeply investigate the interplays among scientific epistemological beliefs, conceptions of learning science, and conceptions of science assessment and to clarify the nested ecology model. In addition, the role of metacognitive awareness on scientific epistemological beliefs and conceptions of learning science and science assessment were discussed through both quantitative and qualitative results. The quantitative part of the study was conducted with a sampling pool of 240 tenth graders. And, those students’ responses from three questionnaires were used to yield some quantitative indicators (i.e., scientific epistemological beliefs, metacognitive awareness, and conceptions of learning science) and to clarify the interplay between those variables. In general, the quantitative results revealed that students having more sophisticated scientific epistemological beliefs tended to show higher metacognitive awareness while learning science and to express more constructivist-oriented conceptions of learning science. In particular, as long as the students have more sophisticated beliefs about the justification of knowledge; they may tend to express much higher metacognitive awareness and to embrace the constructivist conceptions of learning science. For qualitative part of study, 60 representative students selected from the sampling pool were deeply interviewed about their scientific epistemological beliefs (including beliefs about the nature of knowledge and beliefs about the nature of knowing), conceptions of learning science, and conceptions of science assessment. This study found that most selected students expressed the empiricist beliefs about the nature of knowledge. Through the phenomenographic analyze of selected students’ interview responses, seven categories of conceptions of learning science (i.e., memorizing, preparing for tests, practicing the experiments, the increase of knowledge, applying, understanding, and seeing in a new way) and six categories of conceptions of science assessment (i.e., reproducing knowledge, rehearsing, revealing the learning status, improving learning, applying, and the justification of knowledge) were identified in this study. Moreover, the qualitative results seemed to reveal that, on the one hand, the selected students’ beliefs about the nature of knowing seemed to have greater power to explain students’ conceptions of learning science than their beliefs about the nature of knowledge. On the other hand, their beliefs about the nature of knowledge seemed to more relate to their conceptions of science assessment. This study also implied that students expressing more mature conceptions of learning science tended to hold more cohesive conceptions of science assessment. Furthermore, the qualitative part of this study identified three major forms of students’ nested ecology regarding learning science, that is the complete, partial, and divergent nested ecology. In particular, nearly half of 60 representative students were categorized as the complete nested ecology.
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    高中生對於核能發電爭議之非制式推理思考-兼探網路探究活動之影響
    (2007) 吳穎沺; Ying-Tien Wu
    At the 21st century, preparing learners’ ability to deal with socio-scientific issues has been recognized as an important goal for science education. In science education, previous studies regarding learners’ informal reasoning on socio-scientific issues were mainly conducted with qualitative analyses. With 68 tenth graders in Taiwan, this study initially attempted to explore students’ informal reasoning on a socio-scientific issue both qualitatively and quantitatively. In this study, “nuclear power usage” was used as the socio-scientific issue for the participants to reason. The conduct of this study was divided into two phases: the “informal reasoning exploration phase”, mainly examining the relationship between students’ informal reasoning and scientific epistemological beliefs (SEBs) as well as their cognitive structures, and the “on-line searching task phase”, mainly focusing on the effects of different on-line searching activities on students’ informal reasoning. In the first phase, the students’ SEBs were accessed by a questionnaire; the data regarding the students’ cognitive structures were collected by tape-recorded interviews; and, an open-ended questionnaire was utilized to gather the data about the participants’ informal reasoning on nuclear power usage. The findings derived from the first phase imply that learners’ informal reasoning on a socio-scientific issue is, in general, correlated with their SEBs as well as their cognitive structures regarding this issue. Moreover, it was also found that the students’ usage of the “comparing” information processing mode was the best predictor for their informal reasoning quality, while their beliefs about the nature of science knowing was the second best predictor for their informal reasoning quality. Besides, the importance of the richness of students’ cognitive structures on their informal reasoning regarding a socio-scientific issue was also highlighted. In the second phase, by using a quasi-experimental research approach, thirty-three students were assigned to a “guided searching task group”, while thirty-five students were assigned to an “unguided searching task group”. Both the students in the two groups were asked to search relevant information regarding nuclear power usage on the Internet and integrate what they had searched into a report during the period of two classes (100 minutes). However, the students in the un-guided searching task group were asked to search freely, while those in the guided searching task group were provided with a searching guideline. The results of second phase showed that the two groups of students did not show any significant difference on their searching outcomes (p>0.05), but it revealed significant effects of guided on-line searching task on students’ cognitive structure outcomes as well as on their supportive argument construction (p<0.05). However, the guided on-line searching task in this study did not significantly facilitate students’ reasoning quality. Besides, the interaction between students’ SEBs and instructional conditions on students’ searching outcomes as well as on their cognitive structure outcomes was found; also, the interaction between students’ information commitments and instructional condition on students’ cognitive structure outcomes as well as on their informal reasoning outcomes was revealed. It suggests that, when trying to improve students’ informal reasoning ability in Internet-based learning environments, science instructors should pay more attention to the role of learners’ SEBs and the information commitments in their learning outcomes. In sum, the findings in current study did provide more insights into the nature of students’ informal reasoning on a socio-scientific issue, and also showed some initial evidences on the usefulness of on-line searching activities on learners’ informal reasoning on this issue.