基于三维特征空间的土壤盐渍化遥感模型

针对目前干旱半干旱地区出现的土壤盐渍化问题，以渭干河—库车河流域绿洲为研究区，在分析修改型土壤调整植被指数（MSAVI）、湿度指数（WI）、盐分指数（SI）与土壤盐渍化之间关系的基础上，提出了MSAVI-WI-SI三维特征空间，进而建立了土壤盐渍化监测指数（MWSI）模型。结果表明:该模型与土壤盐分实测值的相关系数R=0.896，精度高于三个指数两两构建的特征空间（MSAVI-WI特征空间，MSAVI-SI特征空间，WI-SI特征空间）的土壤盐渍化监测指数模型（MWI，MSI，WSI），其与土壤盐分实测值的相关系数分别为:0.891，0.894，0.809，突出了三维特征空间的优势。同时，通过MWSI的差异矩阵分析，表明该指数对土壤的盐渍化程度反映灵敏。MWSI能较好地反映盐渍化土壤地表植被、土壤水分及土壤盐分的组合变化，具有明确的生物物理学意义。并且指数简单，易于获取，操作方便，对今后干旱区土壤盐渍化的监测与分析具有重要意义。

Remote Sensing Monitoring Models of Soil Salinization Based on the Three Dimensional Feature Space of MSAVI-WI-SI

Monitoring of soil salinization is very important in the arid and semiarid regions. We chose the delta oasis located between the Weigan River and the Kuqa River as the study area. By analyzing the relationship among modified soil-adjusted vegetation(MSAVI), wet index(WI), salinity index(SI) and soil samples, we proposed a concept of MSAVI-WI-SI three dimensional feature space and built a soil salinity monitoring index(MWSI) model. The result indicates that there is a strong correlation between MWSI and surface soil salinity(R=0.896). Monitoring soil salinization with MWSI is more precise than MWI, MSI, WSI based on two dimensional feature space. The correlation coefficients were 0.891, 0.894, 0.809, respectively. Meanwhile, by MWSI difference matrix analysis, the index is sensitive to the level of soil salinization. It suggests that MWSI detect the change of different combination of the vegetation, soil moisture and soil salinity better in the study area. Besides, this index has the clear biophysical meaning. The MWSI has the potential to provide a simple and low-cost monitoring tool for assessment of salt-affected areas.