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为了消除土壤背景信息对植被指数的影响,近几十年发展了土壤调节植被指数系列(SAVI family)。在不同环境条件下,不同指数抗土壤影响的能力不同。在总结了以消除土壤影响为目的的植被指数建立过程的基础上,利用PROSAIL辐射传输模型模拟的两组数据集,比较分析了NDVI、SAVI、TSAVI、MSAVI、OSAVI和GESAVI在不同叶面积指数(LAI)对应不同土壤背景的情况下抗土壤干扰、表达植被信息的能力,指出了不同植被指数应用的最适环境条件。结合植被指数—信噪比图,将这6种植被指数分成3类:在中低LAI值下,若植被覆盖度均匀,OSAVI和TSAVI有较强的消除土壤影响、表达植被信息的能力;当区域LAI分布不均、植被类型混杂时,MSAVI在表达植被信息时具有较好的稳定性。根据每类植被指数的特征,利用MODIS-VI和MODIS-LAI产品初步验证了上述结论的有效性。
In order to eliminate the impact of soil background information on vegetation indices, the SAVI family has been developed in recent decades. Under different environmental conditions, different indices have different ability to resist the influence of soil. On the basis of summarizing the establishment of vegetation index for the purpose of eliminating soil impact, two sets of data sets simulated by PROSAIL radiation transmission model were used to analyze the relationship between NDVI, SAVI, TSAVI, MSAVI, OSAVI and GESAVI in different leaf area index LAI), which can resist soil disturbance and express vegetation information under different soil backgrounds, and pointed out the optimal environmental conditions for different vegetation indices. Combined with the vegetation index - signal-noise ratio (SNR) maps, the six vegetation indices are divided into three categories: OSAVI and TSAVI have strong soil alleviating ability to express vegetation information at low and medium LAI values. The regional LAI is unevenly distributed. When vegetation types are mixed, MSAVI has better stability in expressing vegetation information. According to the characteristics of each type of vegetation index, the validity of the above conclusion is validated by MODIS-VI and MODIS-LAI products.