奈曼旗土地退化遥感监测研究

奈曼旗是土地退化比较严重的旗县,为查清该旗的土地退化类型、分布及程度,监测其土地退化的发展趋势,该文选取土地利用/覆被方式、复合植被指数、风蚀土地占像元面积百分比和土壤含水率作为土地退化评价体系的4个指标,利用TM数据获取4个指标的反演数据。采用层次分析法构造4个指标的判断矩阵,通过判断矩阵特征向量的计算得到土地退化指标的权重,构建土地退化综合评价公式。结合综合评价公式,计算出奈曼旗的土地退化结果,并将土地退化分为未退化、轻度退化、中度退化、重度退化和严重退化5个等级。1987年、1991年、1996年、1999年、2002年和2007年的土地退化评价结果表明,奈曼旗的土地退化在1987-1999年期间处于"局部好转、整体恶化"的局面,2000年以后土地退化扩展趋势得到遏制,土地退化治理取得了一定的效果。该研究对奈曼旗的土地退化防治和生态建设具有一定的指导意义。

Study on land degradation monitoring in Naiman county using remote sensing

Naiman county is one of the counties with serious land degradation. In order to figure out its degradation type, distribution and degree and monitor its degradation process and trend, the land use/coverage change, sandy area ratio in a pixel, composite vegetation index, and soil moisture were selected as four indexes of land degradation evaluation system. All the four indexes were retrieved from TM images. Then the judge matrix of four indexes were constructed using analytical hierarchy process, the eigenvector of judge matrix was calculated to obtain the weight of four indicators. Finally the model of land degradation estimation system was built with four weights. According to the model, the land degradation of Naiman county was classified into 5 levels, no degradation, slight degradation, medium degradation, bad degradation and serious degradation. The degradation evaluation results demonstrated that land degradation of Naiman county had a improvement in some local area, but overall worsening during 1987-1999, while the land degradation has been constrained and degradation treatment has gained some effect since 2000. The research is of some importance and guidance to the degradation treatment and ecological construction in Naiman county.