基于NDVI-SI特征空间的土壤盐渍化遥感模型

    Remote sensing monitoring models of soil salinization based on NDVI-SI feature space

    • 摘要: 同时考虑植被和土壤信息,构建盐渍化遥感信息提取模型。选取具有长期研究基础的塔里木南缘于田绿洲为研究靶区,综合分析归一化差值植被指数(NDVI)、盐分指数(SI)二者之间的关系,在此基础之上提出NDVI-SI特征空间概念,并构建土壤盐渍化遥感监测指数模型(SDI),结果表明:土壤表层含盐量与SDI相关性较高,其R2=0.8596。非盐渍地、轻度盐渍地、中度盐渍地、重度盐渍地的SDI平均值分别为0.399,0.763,0.974和1.201,差异较大;经差异性矩阵分析,亦表明SDI能够很好的区分研究区内不同盐渍化程度地类的分布范围。SDI能反映盐渍化土壤地表盐量组合及其变化,具有明确的生物物理意义,并且指标简单、易于获取、有利于盐渍化定量分析与监测,对今后干旱区盐渍地信息提取以及动态监测研究具有重要意义。

       

      Abstract: Based on vegetation and soil information, remote sensing model was established for extracting soil salinization. In this paper, the Delta oasis of Yutian in the south of Tarim Basin was chosen as the case study for its long-term research accumulation. The relationship between salinization index (SI) and normalized difference vegetation index (NDVI) was analyzed synthetically. Through experimental analysis and theoretical derivation, the research proposed a conception of NDVI-SI feature space and discussed its biophysical characteristics. Analysis revealed that location could be used to improve the current strategies for salinization in the NDVI-SI feature space. The research presented a model of salinization detection index (SDI) to monitor severity of salinization. The results showed that the correlation between the SI and soil salt content had a higher accuracy about 0.8596. The SDI values of non-salinized soil, slightly salinized soil, moderately salinized soil and severely salinized soil were 0.399, 0.763, 0.974 and 1.201, respectively. Results of difference matrix indicated that the SDI had a higher separability in difference scale of soil salinization. The SDI demonstrates a much better performance in measuring salinity soil since it takes into account both topsoil spectrum and halophytic vegetation growth condition in the modeling process. The SDI has the potential to provide a simple and low-cost monitoring tool for assessment of salt-affected areas.

       

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