本文利用由遥感影像解译获得的土地利用数据和MODIS NDVI产品,采用空间转移矩阵、最大值合成法、均值法和一元线性回归模拟等方法, 分析了2000年以来京津风沙源区生态环境变化的时空特征.结果表明:(1)2000- 2005年京津风沙源区耕地开垦、林草地减少的趋势有所减缓,但区域气候变化趋于干旱,水域面积明显减少,草地退化和未利用土地增加的现象依然存在.(2)该区人类活动对生态环境的干扰程度有所减缓,但居住用地和城乡工矿用地的快速增长给生态环境带来了很大压力.(3)2000-2005年京津风沙源区生态环境总体有所好转,春季最大NDVI值呈现明显上升的趋势.本区生态环境的好转表明京津风沙源治理工程的实施已经初显成效.

We investigated the evaluative process of ecological environment of the Beijing-Tianjin sand and dust source region since 2000 based on three periods of land-use data (1995,2000 and 2005), which were acquired from interpretation of TM images, and NDVI product of MODIS. The spatial conversion matrix method, average value method, MVC(Maximum Value Composites)method and linear regression of one variable method were adopted to analyze the trends of land use and vegetation cover condition. The results show that: (1) the tendency of farmland reclamation has decreased; the rate of grassland and forest reducing has decreased, too; and the area of water bodies reduced, because of the arid climate. The phenomenon of grassland degradation and unused land increasing still exists. (2) The disturbing degree of human activities on ecological environment got slow down; but the rapid growth of residential land and industrial and mining land has brought great pressure to ecological environment of the study region. And (3) the research on the change of maximum value of NDVI shows that the NDVI has increased in the study region. That means the vegetation cover condition becomes better. With the comprehensive analysis on the arid climate, we consider that the trend of ecological environment deterioration in the study region has been restrained. The regulation programs of the Beijing-Tianjin sand and dust source region has showed its effect.