基于遥感和像元二分模型的内蒙古正蓝旗植被覆盖度格局和动态变化

以内蒙古锡林郭勒盟正蓝旗为研究区,应用中国环境与灾害监测预报小卫星数据(HJ-1A CCD)及美国陆地卫星数据(Landsat ETM+),在充分考虑区域土壤和植被类型等背景基础上,先后使用了MNF、二维散点制图以及PPI方法,得到具有时空针对性的纯净像元;以此为基础,运用像元二分模型计算得到研究区植被覆盖度空间分布数据;最后,结合研究区其它权威土地覆被和土地利用(LUCC)数据,对比分析了本研究所得的植被覆盖度数据精度,评价了2000~2009年间区域植被覆盖度动态变化过程,指出本区在实施有关生态工程后植被覆盖度恶化趋势得到遏制。研究结果证明,在锡林郭勒盟正蓝旗地区应用像元二分模型计算植被覆盖度的方法是简洁且有效的。

Vegetation Coverage Distribution and Its Changes in Plan Blue Banner Based on Remote Sensing Data and Dimidiate Pixel Model

Vegetation fraction is a general and quantitative index related with vegetation growth,and it has many important applications in the water resources,land desertification,regional ecology and global change research.The authors selected Plain Blue Banner of Inner Mongolia as a case study region,and used the remote sensing data from the Chinese Environmental Disaster Monitoring and Forecasting Satellite data(HJ-1A CCD) and the American Landsat ETM+ data.In the study,the background factors including soil and vegetation type were fully considered firstly,and then the MNF(Minimum Noise Fraction),2-D scatter plot,and PPT(Pixel Purity Index) method were then applied to obtain the pure soil pixels and pure vegetation pixels.Based on the above NDVI index of pure pixels,the dimidiate pixel model was applied to calculate the regional vegetation fraction distribution.Finally,the result datasets were compared with other authoritative land cover / land use dataset and the accuracy was believed to be acceptable.The regional vegetation change tendency during 2000 and 2009 was also assessed,and it infer to a good transition after the implementation of large scale ecological engineering in Plain Blue Banner from 2000.In the paper,the method of dimidiate pixel model was proved simple and effective in the case study region.Also,a meaningful conclusion about the effects of ecological engineering was deduced base on ETM+ and HJ-1A data sets.