基于GIS和RS的赣江上游流域土地利用动态趋势分析

Abstract

利用赣江上游流域1990、1995、2000、2005和2010年5期的TM影像以及2010年的SPOT影像资料，通过目视解译方法及GIS软件的空间叠加分析功能，获取了研究区土地利用覆被变化数据。在此基础上，结合1990-2010年赣江上游流域的统计资料利用灰色关联分析和主成分分析法进行分析，找出引起土地利用变化的主导因素。结果表明：研究区20年来林地和建设用地总量增加，耕地、草地、水域和未利用地总量减少。相同时期不同类型的土地利用变化的驱动因子不相同，不同时期同一类型土地利用变化的驱动因子也不相同。再利用GM（1，1）灰色预测模型预测了2015-2030年间研究区驱动因素和土地利用情况，研究表明主导因素对土地利用变化的影响与1990-2010年间变化趋势一致。;Land use change has become a hot issue on the global climate change research, which includes two aspects: one is the study of land use change process, and the second is the driving factors of land use change. Ganjiang is the greatest river of the Poyang Lake watershed, of which the watershed area accounted for 51.5% of Poyang Lake basin. Ganjiang plays a vital role in the development of social economy of Jiangxi Province. As an important area for water conservation, ecological protection and restoration of Jiangxi Province, the ecological and environmental conditions of Ganjiang upstream are the foundation that the Ganjiang watershed ecosystem depends on existence and development. It is also the premise for ensuring the ecosystem health of the whole Poyang Lake watershed. This study used the TM images of Ganjiang upstream watershed of the year 1990, 1995, 2000, 2005 and 2010 as well as the SPOT image data of 2010, by visual interpretation method and GIS software space, obtaining the land use cover change data of the study area. On this basis, the authors used the methods of grey relational analysis and principal component analysis to analyze the statistics of the Ganjiang upstream watershed between 1990 and 2010, and found the drivers of land use change. Then GM (1, 1) gray prediction model was used to predicate the driving factors and land use change of the study area between 2015 to 2030. The results are as follows. First, from the point of view of single land use dynamic degree, the land use degree of Ganjiang upstream watershed was on the rise from 1990 to 2010. Of the six kinds land-use types, from 1990 to 1995, construction land has the highest single land use dynamic degree, followed by water, woodland has the minimum value. From 1995 to 2000, unused land has the highest single land use dynamic degree, followed by water, woodland has the minimum value. From 2000 to 2010, construction land has the highest single land use dynamic degree, followed by grassland, woodland has the minimum value. From the point of view of comprehensive land use dynamic degree, the comprehensive land use degree of Ganjiang upstream watershed showed a trend to increase in 1990-2010. The extent of land use change of various land-use types has the largest value (10.89‰) between 2000 and 2010. Over the 20 years from 1990 to 2010, the area of agricultural land, grassland, water area and unused land decreased, whereas the area of construction land and forest land increased. Second, the grey relational grade of population, GDP, fixed assets investment, urbanization level, the proportion of secondary industry and tertiary industry proportion is greater than 0.5. This indicates that the six factors are the driving factors of land use change influencing the 16 counties and cities in the Ganjiang upstream watershed. These six factors have different impacts on the various land use change. Third, the driving factors of land use change are different for various land types during the same period and for the same land type in different periods. Finally, over the next 20 years, Ganjiang upstream watershed would have a steady growth in population and urbanization level, thus making the corresponding construction land area constantly increasing, whereas the arable land area continuously decreasing. Construction land area and GDP have synthetic growth trends. The forest area gradually would increase, whereas water and unused land area would slowly decrease.