额尔齐斯河-斋桑湖流域近20年来土地利用/土地覆被时空演变

土地利用/土地覆被变化(LUCC)是影响生态环境和气候变化的主要驱动力之一,同时又是受其影响的结果。LUCC研究对于开展生态环境变化及气候变化的研究均具有重要的意义。针对目前境外LUCC研究中土地利用/覆被分类效率低的问题,探索一种适用于大数据量而又精度较高的分类方法。以额尔齐斯河国外部分-斋桑湖流域为研究区域,以1990年及2007年的Landsat TM/ETM+夏秋季影像以及DEM作为数据源,综合利用影像光谱、纹理信息参与到决策树构造中,进而利用决策树分类方法分别提取这两个时期的土地利用/覆被空间分布信息,最后分析两个时期的土地利用时空变化状况。实验结果表明:(1)光谱与空间纹理信息参与的决策树分类方法具有较高的分类精度;(2)两个时期的土地利用变化分析发现,近20年来该区域土地利用发生了较大的变化,耕地和灌木林地大面积减少,而低覆盖度草地和未利用地却显著增加。

Land use/land cover in Irtysh River-Zaysan Lake Basin over the past 20 years

The land use/land cover change is one of the main driving forces that affect the ecological environment and climate change,and also the result of its impact.LUCC research for the conduct,of eco-environmental changes and climate change studies is of great significance.View of the current LUCC study,land use/cover classification accuracy and efficiency is low.On focus this issue,the paper tries to find a new classification method that can be used to the large scale data classification and also has a more classification precision.The paper takes Irtysh River -Zaysan Lake as the study area,and Landsat TM/ETM+image in year 1990 and 2007 as well as Aster DEM as data source,and comprehensive utilization of imaging spectroscopy,texture information to participate in the deci- sion tree structure,and then take decision tree classification method to extract information of the two periods land use/land cover,and finally to analysis the LUCC information of this area.The results show as follows:(1)the combination of the image spectrum and texture increased the decision tree's classification precision dramatically;(2)The study area has a great change in land use in the past 20 years,especially the farmland and shrub de-creased,while the grassland and unused land increased significantly.