中文摘要：

选择黑河中上游草地植被的典型区域,利用卫星遥感、GIS以及GPS定位测量技术,结合实地调查和采样测定,构造基于地面实测数据的草地植被退化指数,建立草地植被退化的遥感监测模型,并利用研究期2003年TM影像GPS定位点所对应的灰度数据,对1986年TM影像进行辐射特征标准化处理,监测草地植被退化的时空变化规律,旨在探讨通过TM影像数据结合野外样方数据,简单而快速评价草地植被退化的定量方法。结果表明：利用卫星遥感数据和地面草地样方实测数据,分析草地植被退化地面评价指标与遥感评价指标之间的关系,建立草地植被退化的遥感评价模型,能够较为快速、准确地监测和评价区域尺度的草地植被退化。研究区1986年轻度、中度和重度退化的面积分别为499.86、772.67和916.74km^2,2003年轻度、中度和重度退化的面积分别为322.23、815.20和1015.84km^2。从草地植被的变化幅度、变化趋势和变化强度方面对比分析1986年和2003年的草地植被退化情况表明草地植被退化过程是一种慢速的渐变过程,重度退化、中度退化的比例较高而且呈增长趋势,总体态势仍旧呈现退化加剧、局部改善、整体恶化的变化格局。草场退化呈现由草原草场向荒漠化草原草场再向荒漠化草场演替的趋势。

英文摘要：

The severity of grassland degradation in the typical regions near the middle and upper reaches of Heihe River Basin,Western China was assessed from TM image in conjunction with in situ samples of above-ground biomass, fractional grassland cover and palatable grass percent collected over 1 m^2 sampling plots.The above-ground biomass, fractional grassland cover and palatable grass percent were integrated to develop a grassland vegetation degradation index（GDI）.Remote sensing-based monitoring model for grassland degradation was established through regression analyses between GDI and vegetation index derived from TM image.The results of dynamic monitoring situation of grassland degradation using RS,GIS,and GPS techniques showed as follows TM imagery,in conjunction with in situ grassland samples data,could the efficient and accurate assessment of grassland degradation in regional scale,The degradation manifested three levels of degradation severity：severe,intermediate,and slight degradation.The area of severe,intermediate,and slight degradation was 499.86 km^2 ,772.67 km^2 and 916.74 km^2 ,respectively,in 1986;322.23, 815.20 and 1015.84 km^2 ,respectively,in 2003.The overall situation presented both area and intensity of grassland degradation increased significantly,the degree of degradation worsened as well from 1986 to 2003.