:::
| Paper category | PhD |
|---|---|
| Student ID No. | 103686602 |
| Name | 阮金英 Kim-Anh Nguyen |
| Title | 整合遙感，GIS和AHP評估越南承天順化省的生態環境脆弱度 Integrating Remote Sensing, GIS, and AHP to Assess Eco-environmental Vulnerability for the Thua Thien-Hue Province, Vietnam |
| Adviser | 劉說安、李明旭 Yuei-An Liou、Ming-Hsu Li |
| Graduation date | 2017-06 |
| Attached file | |
| Reference link | https://etd.lib.nctu.edu.tw/cgi-bin/gs32/ncugsweb.cgi?o=dncucdr&s=id=%22GC103686602%22.&searchmode=basic |
| Abstract | 生態環境脆弱度評估對於環境和資源管理至關重要。然而，要進行大範圍的生態環境脆弱度評估則是一個困難而複雜的過程，因為它受許多變數的影響，包括水文氣象、地形、土地資源和人類活動。越南承天順化省(Thua Thien–Hue Province)擁有豐富的自然人文景觀，香水河(Perfume River)為境內最大的流域系統，對越南中北部沿岸地區的社會經濟發展非常重要，但卻缺乏環境管理上該有的環境保護分區制度。 本研究以衛星遙測資料結合層級分析法(Analytic Hierarchy Process, AHP)與地理資訊系統(Geographical Information System, GIS)分析，對越南承天順化省建立一個可評估生態環境脆弱度的量化指標。依時空尺度之脆弱度變化，指標共區分為六個等級之脆弱程度(潛在、輕微、少量、中等、嚴重、非常嚴重)。研究中以三年(1989, 2003, 2014)的Landsat影像資料，探討越南承天順化省的生態環境脆弱度時空變化。並將三年分為1989-2003及2003-2014兩個時期，以出現「嚴重」及「非常嚴重」兩種脆弱度指標的範圍變化為例，嚴重脆弱度佔研究區域的面積百分比於1989、2003及2014年分別由5.9％、7.9％、增加至15％，非常嚴重脆弱度的面積百分比則由1.2％、3.2％增加至7.3％，此兩等級脆弱度主要發生於都市化地區、裸露地、半裸露地、農地與稀疏林地；相反的，在「潛在」脆弱度的表現上，則有相當大的下降趨勢：所佔面積百分比於1989、2003及2014年分別由36.4％、30.9％、增加至19.2％。其餘的脆弱度(輕微、少量與中等)所佔面積百分比為微幅波動，於2003及2014年分別呈現遞增與減少趨勢，不同脆弱度程度所佔面積百分比呈現時空變化的原因可歸納為：1) 砍伐、農業密集化與2003至2014年間三個水力發電計畫的建造；2) 都市化地區的擴張，導致相對於鄉村地區有明顯熱特徵(thermal signatures)的差異。這些發現說明人為的活動導致土地利用與土地覆蓋(LULC)的變遷，擴大生態環境脆弱度，進而增加越南承天–順化省的天然災害潛勢。研究結果發現：地表溫度與常態化差異建物指數NDBI呈現正相關，於1989、2003及2014年分別為0.87、0.89與0.84；而地表溫度與常態化差異植生指標NDVI，則呈現負相關，於1989、2003及2014年分別為-0.81、-0.81與-0.76。除此之外，從1989-2003至2003-2014兩個時期，出現潛在、輕微與中等的熱環境(thermal environment)所佔面積範圍呈現下降趨勢，另由區域規模的角度觀察得知，增加土地變遷的人為活動，已加劇研究區域的環境脆弱度。本研究應用遙測資料結合AHP與GIS分析技巧評估大區域的長期生態環境改變過程，未來可有效應用於其他區域。 Eco-environmental vulnerability assessment is crucial for environmental and resources management. However, evaluation of eco-environmental vulnerability over large areas is a difficult and complex process because it is affected by many variables including hydrometeorology, topography, land resources, and human activities. The Thua Thien–Hue Province and its largest river system, the Perfume River, are vital to the social-economic development of the north central coastal region of Vietnam, but there is no zoning system for environmental protection in this region. This dissertation conducts an evaluation of eco-environmental vulnerability and analysis of influencing factors using Landsat data time series and is organized according to the increased use of satellite-derived land surface variables in the assessment framework. Chapter 3 presents an assessment framework that is proposed to evaluate the vulnerable eco-environment in association with 16 variables with six of them constructed from Landsat 8 satellite image products. The remaining variables were extracted from digital maps, and in situ measurement data. Each variable was evaluated and spatially mapped with the aid of an analytical hierarchy process (AHP) and geographical information system (GIS). An eco-environmental vulnerability map is assorted into six vulnerability levels consisting of potential, slight, light, medium, heavy, and very heavy vulnerabilities, representing 14%, 27%, 17%, 26%, 13%, 3% of the study area, respectively. It is found that heavy and very heavy vulnerable areas appear mainly in the low and medium lands where socio-economic activities have been developing rapidly. Tiny percentages of medium and heavy vulnerable levels occur in high land areas probably caused by agricultural practices in highlands, slash and burn cultivation and removal of natural forests with new plantation forests. Based on our results, three ecological zones requiring different development and protection solutions are proposed to restore local eco-environment toward sustainable development. Chapter 4 introduces an improved assessment framework proposed to combat insufficient historical data measurement to examine the eco-environmental changes in both spatial distribution and vulnerable magnitude over the past 20 years (1989-2014) with involvement of 12 variables, mainly retrieved from satellite data with incorporation of analytical hierarchy process (AHP). Six vulnerability levels of potential, slight, light, medium, heavy, and very heavy were graded to depict changes of vulnerability over temporal and spatial scales. The proposed approach was employed to study spatiotemporal eco-environmental vulnerability with Landsat data acquired in 1989, 2003, and 2014 for the Thua Thien - Hue Province, Vietnam. Over the time periods of 1989-2003 and 2003-2014, both heavy and very heavy vulnerability levels exhibit an increasing trend in both magnitude and spatial size: The former raised from 5.9% in 1989, to 7.9% in 2003, and 15% in 2014; and the later increased from 1.2% in 1989, to 3.2% in 2003, and 7.3% in 2014. Both levels mainly appeared on urbanized area, bare land, semi-bare land, agricultural land, and sparse forests. In contrast, there was a significant decline in potential vulnerability level with 36.4% in 1989, 30.9% in 2003, and 19.2% in 2014, while the remaining vulnerability levels slight, light, and medium fluctuated slightly, increased in 2003 and decreased in 2014. Supporting reasons for such changes include: (1) deforestation, agriculture intensification, construction of three hydro-electric projects during the period 2003-2014; and (2) significant expansion of urbanized area leading to differences in thermal signatures in urban areas as compared with rural areas. The findings demonstrate that eco-environmental vulnerability is primarily exaggerated by anthropogenic activities through land use/land cover (LULC) changes and further enhanced by natural processes including disasters in the Thua Thien - Hue Province of Vietnam. The correlation between land surface temperature (LST) and Normalized Difference Built-up Index (NDBI) is found to be positively correlated with 0.87, 0.89, and 0.84 for 1989, 2003, and 2014, respectively. In contrast, LST-Normalized Difference Vegetation Index (NDVI) is found negatively correlated with respect to the spatiotemporal trend of environmental vulnerability with -0.81, -0.81, and -0.76 in 1989, 2003, and 2014, respectively. In addition, areas having potential, slight, and medium thermal environmental levels are decreased from 1989-2003 to 2003-2014. At the regional scale, increased anthropogenic activities through land’s modification have intensified the eco-environmental vulnerability in the study area. The currently proposed methodology is feasible for evaluating long-term eco-environmental changes processes by using remote sensing data, and valid for the other regions and proper planning for land use and construction in the future. Chapter 5 presents summary and conclusions that include the major findings and contributions of the dissertation and recommendation for future research. |
| Bibliography |
