半干旱地区土地退化遥感动态监测方法-以吉林省通榆县为例

在RS和GIS集成技术支持下 ,选取位于半干旱地带的土地退化典型地区 -吉林省通榆县 ,利用不同时相的TM卫星数据 ,采用噪声白化变换提取光谱特征 ,选用植被、盐碱地、裸沙地、沼泽土、苇地作为最终光谱单元进行线性混合光谱分解 ,依据盐碱地和裸沙地加权和分量 ,将试点区的土地退化划分为未退化、轻度退化、中度退化和重度退化四个等级进行动态监测 ,并对土地退化的数量、空间分布与动态过程进行了分析。这一研究方法与结果可为半干旱地区的土地退化监测与生态建设提供科学方法和依据。

A Method of Remote Sensing Dynamic Monitoring of Land Degradation in Semi-arid Region-A Case Study:Tongyu County in Jilin Province

Land degradation is an exhibition of the deterioration of agricultural eco-environment,derived from the fragile nature environment and human activity. In this paper,we used two temporal Landsat TM/ETM data of 1989 and 2001 to evaluate the land degradation of a semi-arid area in the Tongyu county of Jilin Province. We applied Minimum noise fraction (MNF) transforms to determine the inherent dimensionality of image data, to segregate noise in the data. Spectral mixture model (SMM) was adopted, which is an image-processing technique used for the analysis of airborne hyperspectral remote-sensing data which consist of a large number of spectral bands, typically over 100. Five endmembers were derived from the image analysis,including vegetation,salina,desert,marsh, reed swarm. We grade land degradation into four levels according to the weight sum of salina and desert. With the support of ENVI and ARC/INFO,we also analyzed the amount,spatial distribution and dynamic change of land degradation in the study area.