基于遥感与GIS技术的彭州市地震灾区植被动态变化监测与评价

发布时间：2018-03-03 17:40

本文选题：地震　切入点：植被受损　出处：《四川师范大学》2013年硕士论文　论文类型：学位论文

【摘要】：生态环境是人类社会赖以生存和发展的基本要素，保护生态环境，建设生态文明是关系人民福祉、关乎民族未来的基本国策。在自然的生态环境中，植被是自然生态系统中最为重要的组成部分，它为人类的生存提供必需的氧气和食物，同时植被生长的状态健康与否是判断自然生态环境好坏的重要指标。2008年汶川大地震，地处龙门山脉腹地的彭州市成为受灾最为严重的地震极重灾区之一，生态环境受到了巨大的破坏，植被受损变化突出。研究植被受损程度、面积和分布特征，评估地震造成的生态环境影响，以及评价震后四年植被与生态环境恢复，对于指导后期植被恢复和生态环境重建都有着十分重要的意义。本研究在查阅大量相关的国内外文献的基础上，针对本研究区的地理信息要素，进行植被的受损与恢复研究。使用的是ETM+的遥感影像、CBERS-02B卫星的遥感影像和环境减灾卫星作为植被受损恢复提取的数据源，首先建立植被的受损与恢复模型，逐次对高程、坡度、坡向进行分级统计，分析情况。依据生态环境评价因子的选取原则，选用准则层和指标层，建立本研究区的生态环境评价指标体系，选用层次分析法和综合指标法建立生态环境评价综合模型，利用地理信息技术的空间分析和栅格运算，对生态环境进行评价，计算出彭州市震后四年生态环境变化分级结果。其主要结论有：（1）对植被提取时，着重分析了山体阴影对植被提取的影响，经过对各个地物的光谱采样分析，发现山体阴影在各个波段的值均小于其他地物，所以基于此就提取出山体阴影。再在山体阴影这个单独的地类中，试验NDVI的阈值范围，从而提取出山体阴影里的植被。（2）建立植被受损模型，发现受损植被的总面积为112.64km2，占彭州市总面积7.9%。分析重度、中度、轻度受损地区的植被分布。经研究发现受损植被的空间分布与海拔有明显正相关，其次是坡度因子，而与坡向因子相关性并不大。（3）建立植被恢复模型，分析恢复等级的分布特征。综合分析来看，影响植被恢复的因子主要是海拔高度和坡度因子，受坡向的影响较小。（4）选择七个指标对地震后的生态环境进行评价，并将其结果划分为五个等级，分析得出在有林地，灌木林地中，植被恢复等级为良的，坡度在35°以下的，，生态环境等级为良好的地区，其生态环境的恢复是最好的。（5）根据评价的结果，有助于相关部门及时的从整体上把握整个研究区的变化情况，为本研究区灾后的植被恢复和生态系统的重建提供科学的参考依据。
[Abstract]:Ecological environment is the basic element of the survival and development of human society. The protection of ecological environment and the construction of ecological civilization are the basic national policies related to the well-being of the people and the future of the nation. Vegetation is the most important component of natural ecosystem. It provides essential oxygen and food for the survival of human beings. At the same time, the state of vegetation growth is an important index to judge the quality of natural ecological environment. Pengzhou City, located in the hinterland of the Longmen Mountains, has become one of the most severely affected earthquake stricken areas. The ecological environment has been greatly damaged, and the vegetation has been damaged and changed significantly. The extent, area and distribution characteristics of vegetation damage have been studied. It is very important to evaluate the impact of the earthquake on the ecological environment and to evaluate the vegetation and ecological environment restoration in the four years after the earthquake. On the basis of consulting a large number of relevant domestic and foreign literatures, this study aims at the geographical information elements in this research area. Using the remote sensing image of ETM remote sensing image of CBERS-02B satellite and environmental disaster reduction satellite as the data source of vegetation damage recovery and recovery, the damage and restoration model of vegetation was established first, and the elevation and slope were successively evaluated. According to the selection principle of ecological environment evaluation factors, the index system of ecological environment evaluation in this research area is established by selecting criterion layer and index layer. The synthetic model of ecological environment evaluation is established by AHP and comprehensive index method, and the ecological environment is evaluated by spatial analysis and grid operation of geographic information technology. The classification results of ecological environment change in Pengzhou City for four years after the earthquake are calculated. The main conclusions are as follows:. 1) in the process of vegetation extraction, the influence of mountain shadow on vegetation extraction is emphatically analyzed. The spectral sampling of each feature shows that the value of mountain shadow in each band is lower than that of other ground objects. Therefore, the mountain shadow is extracted based on this, and then the threshold range of NDVI is tested in the mountain shadow, which is a separate ground category, and the vegetation in the mountain shadow is extracted. (2) to establish a model of vegetation damage, it was found that the total area of damaged vegetation was 112.64km2, accounting for 7.9% of the total area of Pengzhou. The distribution of vegetation in heavy, moderate and light damaged areas was analyzed. It was found that the spatial distribution of damaged vegetation was positively correlated with altitude. The second is slope factor, but the correlation with slope direction factor is not great. (3) establish a vegetation restoration model and analyze the distribution characteristics of restoration grade. The factors affecting vegetation restoration are mainly altitude and slope factors, which are less affected by slope direction. 4) selecting seven indexes to evaluate the ecological environment after the earthquake, and dividing the results into five grades. The analysis shows that in the forest land and shrub land, the vegetation restoration grade is good and the slope is below 35 掳. The recovery of ecological environment is the best in areas with good ecological environment grade. 5) according to the evaluation results, it is helpful for relevant departments to grasp the changes of the whole research area in time, and to provide scientific reference for vegetation restoration and ecosystem reconstruction after disaster in the study area.
【学位授予单位】：四川师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P208;X87;X826

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