Abstract:

The NDV I of Ejina Oasis was calculated based on the data derived from Landsat TM /ETM + images in 1996, 2000, 2002 and 2006, and in light ofNDV I’s value the land coverwas divided into four types: the bare land, the sparse vegetation area, the lower vegetation area and the dense vegetation area. Through the comparison of the different grade vegetation area change before and afterwater devision, the restoring effect of the vegetation in Ejina Oasis can be found out, and this can supp ly the scientific foundation for the Heihe water - division p lan of the next step. The monitoring results show that the ecological environment of Ejina Oasis kep t deteriorating before 2002, but after seven - yearwater division from upper andmiddle reaches of Heihe River, the environment deterioratingwas alleviated and vegetation was restoring stage by stage.

Key words: the downstream of Heihe, water division, Ejina oasis, remote sense monitoring

摘要：

利用1996、2000、2002和2006年4个时期的TM数据,计算了额济纳旗绿洲的NDV I,根据NDV I大小划分裸露地、稀疏植被区、中等植被区和茂密植被区4个等级,对比分析黑河分水前后额济纳旗绿洲NDV I的面积变化,了解黑河分水对下游植被恢复的效果。结果表明: 1996～2002年,额济纳旗绿洲植被一直处于退化阶段; 2006年,经过黑河连续7 a的分水,下游植被得到较好的恢复,黑河下游的生态环境退化问题得到了缓解和恢复。

关键词: 黑河下游, 分水, 额济纳绿洲, 遥感监测