Analysis of NDVI and scaled difference vegetation index retrievals of vegetation fraction
Analysis of NDVI and scaled difference vegetation index retrievals of vegetation fraction
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DOI：
10.1016/j.rse.2006.01.003
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发表时间：
2006-04-15
影响因子：
13.5
通讯作者：
Zhang, XY
中科院分区：
文献类型：
--
作者：
Jiang, ZY;Huete, AR;Zhang, XY
归一化植被指数（NDVI）是植被冠层生物物理特性反演中应用最广泛的植被指数。一些研究调查了空间尺度的依赖性的NDVI和植被覆盖率之间的关系，但没有任何共识的两个问题。本文的目的是分析的空间尺度的依赖性的NDVI和分析之间的关系和植被覆盖度在不同分辨率的线性光谱混合模型的基础上。我们的研究结果表明，强烈的空间尺度依赖性的非均匀表面的NDVI，表明在不同的分辨率的NDVI值可能是不可比的。在部分植被覆盖的地表上，植被指数的非线性随着土壤背景的加深和阴影的存在而变得突出。因此，由于其非线性和尺度效应，NDVI可能不适合用于推断植被覆盖度。我们发现，比例差分植被指数（SDVI），一个基于红色和近红外反射率的线性光谱混合的尺度不变的指数，是一个更合适和强大的方法，用于遥感数据，特别是在非均匀表面的植被覆盖率的检索。所提出的方法已经过实地试验数据的验证，但还需要在卫星一级进行进一步验证。(c)2006年爱思唯尔公司All rights reserved.
The normalized difference vegetation index (NDVI) is the most widely used vegetation index for retrieval of vegetation canopy biophysical properties. Several studies have investigated the spatial scale dependencies of NDVI and the relationship between NDVI and fractional vegetation cover, but without any consensus on the two issues. The objectives of this paper are to analyze the spatial scale dependencies of NDVI and to analyze the relationship between NDVI and fractional vegetation cover at different resolutions based on linear spectral mixing models. Our results show strong spatial scale dependencies of NDVI over heterogeneous surfaces, indicating that NDVI values at different resolutions may not be comparable. The nonlinearity of NDVI over partially vegetated surfaces becomes prominent with darker soil backgrounds and with presence of shadow. Thus, the NDVI may not be suitable to infer vegetation fraction because of its nonlinearity and scale effects. We found that the scaled difference vegetation index (SDVI), a scale-invariant index based on linear spectral mixing of red and near-infrared reflectances, is a more suitable and robust approach for retrieval of vegetation fraction with remote sensing data, particularly over heterogeneous surfaces. The proposed method was validated with experimental field data, but further validation at the satellite level would be needed. (c) 2006 Elsevier Inc. All rights reserved.