以福建省三明市沙县为例,利用线性光谱混合模型提取植被覆盖度,在对比原始影像构建的四端元模型与加入归一化植被指数的影像构建的五端元模型反演精度的基础上,选择精度更高的五端元模型估算1996、2004、2014年沙县的植被覆盖度,并分析其变化及景观格局.结果表明:沙县植被覆盖结构以高植被覆盖度为主导,高植被覆盖度的区域面积占全县面积的57.87%以上.1996年植被覆盖度最差,1996—2004年,植被覆盖度大幅度上升,增加区域面积比例高达35.15%; 2004—2014年,由于城市发展需要,植被覆盖度下降明显,下降区域面积占8.99%,主要分布在沙县中部和北面片区.从植被覆盖度的景观格局来看,极低、低、高植被覆盖度的破碎化程度低,分布较为集中;1996—2014年,极低、低植被覆盖度的破碎化程度先降低后升高,与人类活动有着密切关系.%Taking Shaxian County,Sanming City,Fujian Province as an example,vegetation coverage was extraction through four-endmember model builted by original Landsat image and five-endmember linear spectral mixture model built by Landsat image merged with the normalized different vegetation index. After comparing the accuracy of four-endmember and five-endmember, this study used the five-endmember which has higher precision to estimate the vegetation coverage of Shaxian in 1996, 2004, 2014, respectively. This paper analyzed the changes of vegetation coverage and its landscape pattern. The results showed that the vegetation coverage structure of Shaxian mainly was high vegetation coverage which accounted for more than 57.87% in the county area. The worst vegetation coverage was in 1996. In 1996—2004,vegetation coverage significantly increased in a rate of 35.15%. From 2004 to 2014, the vegetation coverage significantly decreased due to urban development in a rate of 8.99%, mainly in the middle and north of Shaxian. From the landscape pattern of the vegetation coverage,the degree of fragmentation of very low,low and high vege-tation coverage were low showing a concentrative distribution. The degree of fragmentation of very low and low vegetation coverage decreased first and then increased during 1996 to 2014,which was closely related to human activities.
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