Abstract: Based on the NOAA AVHRR data and GIS software, we studied on the characteristics of forest-steppe ecotone in the southern edge of Inner Mongolia Plateau. The pattern of NDVI was analyzed through 12 monthly NOAA AVHRR data of the years 1992-1993. Meanwhile, we used standardized principal components as a compressed tool to analysis the working area. And then two principal components was extracted, we found that the component 1 stood for the cumulative NDVI which meant the total biomass; the component 2 represented the variance between the hot months and the cold months which amounted to the fluctuation from the growing periods to the un-growing periods. The component 1 was gradually increased vie the steppe to the forest coincide with the component 2. Finally, the working area was classified by the two principal components, the result of classification is satisfying. It proved that the standardized principal component method is an effective tool for classifying.

Key words: ecotone, NDVI, principal component analysis

摘要： 借助遥感数据和GIS软件，对内蒙古高原东南缘森林-草原过渡带进行研究，利用1992—1993年间12个月份的NDVI资料，分析研究区的NDVI分布格局。同时，通过主成分分析方法，对数据进行降维，提取前两个主分量，其中第一主分量代表NDVI的累计，第二主分量代表NDVI的年内变动程度。结果表明，由荒漠化草原带到森林带，在其第一主分量逐步增加的同时，第二主分量也随着增加。最后，再利用上述所得的两个分量对研究区进行监督分类，分类结果较为满意。

关键词: 森林-草原过渡带, NDVI, 主成分分析