【作者】 银山；

【导师】 王林和；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2010， 博士

【摘要】 浑善达克沙地属中温带半干旱大陆性季风气候区。在自然和人为的共同作用下,该区的土地荒漠化问题严重威胁着当地和周边地区社会经济发展和生态安全。为更好地对该区荒漠化发展进行实时动态监测,了解荒漠动态变化,解释荒漠化发生发展的内在机制,服务于区域荒漠化的综合、科学防治,本文以RS、GIS技术、景观生态学原理和DEM方法为支撑,采用数理统计与数学建模的方法,对浑善达克沙地近17年荒漠化动态变化进行了分析,讨论了TM、MODIS方法的荒漠化监测和基于DEM的荒漠化分析,最后探讨了浑善达克沙地土地荒漠化动态变化的驱动机制,主要研究结果如下:1、浑善达克沙地荒漠化土地的分布,由东向西荒漠化程度逐渐加剧,1989～2000年间浑善达克沙地的荒漠化土地面积扩大、荒漠化程度加剧,荒漠化状况整体恶化;2000～2007年间荒漠化整体得到遏制,局部地区开始逆转,生态环境明显好转,植被有所恢复。经历了1989～2000年的荒漠化发展过程和2000～2007年的荒漠化逆转过程。2、NDVI估算植被覆盖度的结果显示,植被覆盖度变化与荒漠化变化密切相关。随着植被覆盖度的提高,荒漠化土地逆转;植被覆盖度的降低,荒漠化土地扩张。2000～2007年内植被覆盖度提高,荒漠化土地出现逆转。3、荒漠化景观指数的计算结果表明,1989～2007年间荒漠化景观的斑块个数、斑块密度和斑块破碎化指数增加;平均斑块面积和边缘密度减少;以2000年为转折点斑块面积变异系数先减后增、平均斑块面积和斑块面积百分比先增后减。荒漠化景观指数的上述变化规律,很好的反映研究区两个阶段荒漠化土地的恶化和逆转情况,可见荒漠化景观指数是从景观生态学的角度研究荒漠化的有效途径之一。4、利用EOS-MODIS遥感数据计算出归一化植被指数(NDVI)和植被覆盖指数(PV),反演求得荒漠化指数(DI)结果显示:荒漠化变化趋势及各种程度荒漠化土地的变化,基本上与该地区气候变化特征吻合,特别是荒漠化的变化基本与降水量的波动基本一致。2000—2007年间,中度、重度和极重度荒漠化土地较大幅度减少,未荒漠化土地和轻度荒漠化土地相应增加。归一化植被指数(NDVI)和植被覆盖指数(PV),反演求得荒漠化指数(DI)结果与TM遥感目视解译荒漠化的结果相符。5、利用DEM研究荒漠化土地分布和动态变化,能很好的反映荒漠化土地在不同高程、坡度和坡向的分布和变化规律。研究结果显示,在高程的分布,荒漠化土地主要集中分布在2级(1150～1250 m)和3(1250～1350 m)级高程上,2级、3级和4级(1350～1450 m)高程的荒漠化土地变化最为明显;在坡度级上,荒漠化土地集中分布在4(<15°)级以下的坡地上,3级(<10°)以下的坡地是荒漠化土地变化最突出的坡地。根据不同坡度的荒漠化土地的动态变化规律,荒漠化的防治工作的重点应是坡度小于10度的坡地。6、荒漠化的发生、发展是自然和社会经济的共同作用的产物,荒漠化的自然原因包括地貌条件、土壤质地、植被变化以及气候变化等,其中气候变化是荒漠化的主要的自然动力条件;社会经济因素涉及到多方面的因素,如人口与土地利用、经济结构、政策因素等。更多还原

【Abstract】 The Hunshandake sand land located in the warm temperate zone which is continental monsoon climate area. However, desertification is the serious problem for the development of the economy and eco-safety. In order to do the better dynamic monitoring of the desertification development in the area and further understanding the dynamic development and the internal mechanism of desertification, this paper, use the techniques of RS and GIS, prepare the principles of the landscape ecology, the theory of DEM, the method of mathematical statistic and modeling, to analyze the dynamic changes of land desertification in Hunshandake sand land that the time period about 17 year. At same time discuss the monitoring of land desertification in three ways that are TM, MODIS and DEM data and the drive mechanism of Hunshandake sand land desertification. The results are as follows:1. The distribution degree of Hunshandake sand land desertification is increased gradually from east to west. The area of the land desertification increased and the degree of the land desertification extended; the land desertification deteriorated as a whole from 1989 to 2000 year. Between 2000 and 2007, the land desertification is limited in the whole and reversed in some area. From 2000 to 2007 year, the ecological environment is improved and the vegetation has been restored.2. The results of NDVI vegetation coverage shows that the changes of vegetation cover and land desertification are closely related. With the increasing of vegetation cover, the land desertification is reversed; and with the reducing of vegetation coverage, the land desertification is extended.3. The calculation results of desertification landscape index indicated, in the period of 2000-2007, the index of landscape patch number, patch fragmentation and patch density are increased. The average patch area and edge density are decreased. The variation of landscape index of land desertification indicated perfectly the deterioration and reversion of land desertification in above. It can be known, the index of landscape of desertification is a valid method of the studies in land desertification from landscape ecology.4. Using the EOS-MODIS remote sensing data calculated the index of normalized difference vegetation (NDVI) and the index of vegetation cover (PV), to obtain the results of the desertification index (DI): the trend of land desertification changes and the changes of land desertification degree are coincided basically with the climate changes in this area. Especially, the changes of land desertification and the fluctuation of precipitation are agreement. Between 2000 and 2007, the land of moderate, severe and very severe land desertification are decreased significantly. Considering the slight land desertification is increased. The index of normalized difference vegetation (NDVI), the index of vegetation cover (PV) and the land desertification index (DI) are fitting with the results of TM remote sensing visual interpretation.5. Take DEM to analyze the desertification distribution and land use dynamic change, it can commendably represent the distribute regulation that based on different elevation, slope and aspect variation. The final results, the classified degrees of desertified land are concentrated between two and three elevation grade, it is most obvious in 2, 3 and 4 elevation grade; Take the reference of slope grade, the desertified land variation are mainly distributed in grade 4 slope which is below 15 degree, the desertification variation change most in grade 3 slope which is below 10 degrees. According to the desertification dynamic change regulation based on slope that the pivot and key of desertification prevention and control should be focused on the slope gradient of less than 10 degrees.6. The occurrence and the development of land desertification are results of natural and socio-economic development. The natural cause of the land desertification consist of topography, soil texture, vegetation changes and climate change, for the key item, the climate change is the most important natural dynamic condition. The socio-economic factor included many aspects, such as population, land using, economic structure and policy factors.更多还原