臺灣博碩士論文加值系統

　　臺灣冬天因東北季風水氣受到中央山脈阻擋，使得中南部地區冬天多乾旱，且柳中明等人（2008）研究顯示臺灣西部地區小旱發生的範圍有向上游集水區擴展之現象，若植物面臨長時間的缺水逆境，恐會對植生生長造成衝擊。本研究以臺灣中部蓮華池試驗林區為研究區，選取秋冬至翌年早春的SPOT衛星影像，並分析1981-2010年的逐日氣象資料。計算各期影像的常態化差異植生指標（Normalized Difference Vegetation Index, NDVI），搭配極端植去除法分離混合像元後，分析秋冬至早春不同降雨型態與蓮華池試驗林區植生覆蓋變動之關係，以釐清不同林相與林種面臨不同降雨型態是否會有所差異。最後，瞭解不同降雨型態與不同地形因子對植生覆蓋變動之關係。
本研究分析氣象資料之結果顯示，蓮華池試驗林地區的總降雨量有上升之現象，同時不降雨日數卻有明顯的上升趨勢，表示未來蓮華池地區將面臨降雨強度更強、更極端的降雨型態。值得注意的是1-3月的總降雨量不僅下降且無雨日數亦增加，未來將可能衝擊蓮華池試驗林區的森林生態系。
　　研究結果顯示，森林區面對不同降雨型態干擾後植生的NDVI變動百分比均有顯著差異。此外，秋冬至早春前段雖非蓮華池地區植物的生長季，但乾旱逆境仍會對植物造成傷害。然而秋冬至早春的降雨時間分配並非限制植生生長的因素，這段時間的總降雨量，才是影響植物是否能健康生存與發展的重要關鍵。比較不同降雨型態對不同林相的影響發現，天然林與人工林在面對不同降雨型態的干擾下，亦顯示是否有充足的降水對植生的生長有很大的影響。另外，不同林種與降雨型態干擾的分析結果，顯示檜木、臺灣肖楠、香杉、臺灣杉等臺灣原生種植物對不同降雨型態干擾的波動程度小於非臺灣原生植物的杉木、赤桉等的波動程度。最後，分析不同降雨型態下植生變動與地形間的關係，顯示乾旱逆境於地形因子對植生覆蓋所造成的衝擊關係不大。

　　Winter droughts occur in central and southern Taiwan, because of the northeast monsoon blocked by the Central Mountains. Vegetation exposed to the water shortage status may wither or die. In order to investigate the effect of rainfall patterns on vegetation, the Lien-Hua-Chi experimental forest was selected as the study area, and the normalized difference vegetation index (NDVI) was calculated based on the SPOT images before and after the dry season from the ending of fall to the beginning of spring to monitor the forest changes, including the changes in different forest phase, species and topographic condition.
We analyzed meteorological data including daily rainfall recorded in Sun Moon Lake weather station from October to March to early spring. The results showed that total precipitation and non-rainy days has increased in Lien-Hua-Chi experimental forest, it means the rainfall intensity and patterns may change in the future.
In addition, the study period isn’t growing season in this area, but drought stress also impact on plants. The time distribution of precipitation is not important for plant growth. The total precipitation is the key factor affect the vegetation condition in this period. The drought resistance of native species, such as Taiwania cryptomerioides and Calocedrus formosana, were better than non-native species, such as Cunninghamia lanceolata. This results support the idea that native species are suitable for forest restoration in Taiwan. In addition, the correlation between vegetation aspect factors is insignificant under drought stress conditions.

摘要 i
Abstract ii
謝誌 iii
目錄 iv
圖次 v
表次 vii
第一章　緒論 1
第一節　研究動機 2
第二節　研究目的 4
第二章　文獻回顧 5
第一節　乾旱 5
第二節　水分與植物的生長 7
第三節 遙測監測植生變動 10
第三章　研究材料與方法 20
第一節　研究區概述 20
第二節　研究材料 22
第三節　研究方法 25
第四章　研究結果 44
第一節　極端值去除法的成效 44
第二節 秋末至早春不同降雨型態對蓮華池森林區之NDVI變動影響 53
第三節 不同林相於秋末至早春不同降雨型態之NDVI變動 60
第四節 不同林種於秋末至早春不同降雨型態之NDVI變動 71
第五節 地形因子與NDVI變動之關聯 76
第五章　討論 88
第一節 極端值去除法的成效與限制 88
第二節 秋末至早春不同降雨型態與植生之關聯 89
第六章　結論與建議 92
第一節　結論 92
第二節　建議 94
參考文獻 95
附錄 104
圖次
圖 2-1 光譜反射曲線 10
圖 2-2 植生指標差值法以標準差界定門檻值 18
圖 3-1 蓮華池試驗林區土地利用圖 21
圖 3-2 蓮華池試驗林區林種分布圖 21
圖 3-3 研究流程圖 26
圖 3-4 1981-2010 年降雨量分析 29
圖 3-5 1981-2010 年平均氣溫分析 29
圖 3-6 1981-2010 年相對溼度分析 30
圖 3-7 1981-2010 年不降雨日數分析 30
圖 3-8 2000-2010年秋末、早春風向頻率風花圖 32
圖 3-9 衛星影像去除混合像元前之直方圖 40
圖 3-10 混合像元分布圖 41
圖 4-1 影像去除混合像元後之直方圖 47
圖 4-2 利用極端值去除法混合像元分布圖 48
圖 4-3 極端值去除法偵測未完全去除的雲霧遮蔽處 52
圖 4-4 2000-2010年蓮華池試驗林森林區秋末至早春前、後段NDVI圖 56
圖 4-5 2000-2010年蓮華池森林區秋末至早春兩時段不同降雨型態NDVI變動百分比圖 58
圖 4-6 2000-2010年蓮華池試驗林天然林秋末至早春前、後段NDVI圖 65
圖 4-7 2000-2010年蓮華池試驗林人工林秋末至早春前、後段NDVI圖 67
圖 4-8 2000-2010年蓮華池天然林秋末至早春不同降雨型態NDVI變動百分比圖 69
圖 4-9 2000-2010年蓮華池人工林秋末至早春不同降雨型態NDVI變動百分比圖 70
圖 4-10 2000-2010年前段森林區、天然林、人工林平均NDVI與海拔高度之關係 78
圖 4-11 2000-2010年前段森林區各年NDVI與海拔高度之關係 78
圖 4-12 2000-2010年後段森林區、天然林、人工林平均NDVI與海拔高度之關係 79
圖 4-13 2000-2010年後段森林區各年NDVI與海拔高度之關係 79
圖 4-14 2000-2010年森林區、天然林、人工林平均NDVI變動百分比與海拔高度之關係 80
圖 4-15 不同降雨型態對森林區植生變動與海拔高度之關係 80
圖 4-16 不同降雨型態對天然林植生變動與海拔高度之關係 82
圖 4-17 不同降雨型態對人工林植生變動與海拔高度之關係 82
圖 4-18 2000-2010年前段森林區、天然林、人工林平均NDVI與坡向之關係 85
圖 4-19 2000-2010年後段森林區、天然林、人工林平均NDVI與坡向之關係 85
圖 4-20 2000-2010年森林區、天然林、人工林平均NDVI變動百分比與坡向之關係 85
圖 4-21 不同降雨型態對森林區植生變動與坡向之關係 86
圖 4-21 不同降雨型態對天然林植生變動與坡向之關係 86
圖 4-22 不同降雨型態對人工林植生變動與坡向之關係 86
圖 5-1 極端值去除法分離雲遮與混合像元之成效 88

表次
表 3-1 衛星影像基本資訊 24
表 3-2 研究範圍氣象資料與分類 31
表 3-3 RMSE檢定表 34
表 3-4 各期影像波段資訊 36
表 3-5 去除混合像元前影像之NDVI資訊 39
表 4-1 極端植去除法每次去除混合像元數累積百分比 45
表 4-2 去除混合像元後影像之NDVI資訊 46
表 4-3 未處理混合像元與分離混合像元後的植生變遷分析比較表 50
表 4-4 比較未分離與已分離混合像元的影像其植生減損、未變遷、增加的比例51
表 4-5 2000-2010年蓮華池森林區各年度及不同降雨型態對NDVI之相關資料 55
表 4-6 森林區在不同降雨型態後減損、未變遷、增加的比例 59
表 4-7 2000-2010年蓮華池天然林各年度及不同降雨型態對NDVI之相關資料 ·62
表 4-8 2000-2010年蓮華池人工林各年度及不同降雨型態對NDVI之相關資料 ·63
表 4-9 天然林、人工林在不同降雨型態後減損、未變遷、增加的比例 64
表 4-10 2000-2010年蓮華池內各林種於不同降雨型態之NDVI變動百分比 74
表 4-11 2000-2010年蓮華區林區內各林種於不同降雨型態後減損、未變遷、增加的比例 75
表 4-12 森林區、天然林與人工林坡向與NDVI變動百分比之關聯 87

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