基于NDVI的黄河三角洲植被覆盖度动态变化研究

Study on Dynamic Changes of Vegetation Coverage of Yellow River Delta Based on NDVI

植被覆盖度是研究地表植被状况的重要指标,以黄河三角洲为研究区域,利用该地区1995年、2004年和2010年的三期Landsat-5TM影像数据,提取NDVI,采用像元二分模型,反演植被覆盖度及动态变化趋势,并对植被覆盖度变化的原因进行了浅析.研究结果表明,黄河三角洲地区自1995年以来随着耕地面积的增加,以及由于当地政府对生态环境保护的重视,落实环境保护政策,植被覆盖度整体上有了明显提高,Ⅰ级植被面积从1995年的203.8212 km2增加到2010年的1055.6694 km2,生态环境有了较大的改善.另一方面,随着的城市的快速发展,建筑用地及工业用地的增加,出现了局部地区植被退化,植被覆盖度降低.

The vegetation coverage is the important indicator to study the surface condition of vegetation. The three period image data of Yellow River Delta which is selected as the study area in 1995,2004 and 2010 are used. With the help of the extract of NDVI and dimidate pixel model, the inversion vegetation coverage as well as its dynamic change trend are analyzed. The results suggest that the vegetation coverage has increased dra- matically in Yello River Delta because of the growth of cultivated land area, the attention to the ecological enviroment from the local government and the implementation of environmental policy since 1995. On the one hand ,the Level 1 vegetation coverage has increased from 203. 8212km2 in 1995 to 1055.6694km2 in 2010 and the ecological enviroment has been improved significantly. On the other hand, the rapid development of cities and the increased land utilizaiton of constructions and industries, contribute to a vegetation degradation, decreasing the coverge of vegetation as well.