耕层土壤含水量间接光谱估测模型

为克服光学卫星遥感只能获取表层土壤光谱信息而不能用于直接估测耕层土壤含水量的局限性,建立基于表层土壤高光谱的耕层土壤含水量间接估测模型。以山东省济阳县85个潮土样本的含水量及高光谱数据为基础,根据表层与耕层土壤含水量的内在关系,建立耕层土壤含水量间接光谱估测模型。结果表明,表层土壤光谱反射率的对数变换效果较好,以1339、1457、1745、1969、1996 nm波段的对数变换值为估测因子,采用多元线性回归模型建立的表层含水量估测模型的决定系数为R ²=0.8911,平均相对误差为13.67%;土壤耕层与表层含水量之间存在着显著的相关性,R ²=0.8131;耕层土壤含水量间接光谱估测模型的精度较高,决定系数R ²=0.8138,平均相对误差为9.66%。研究表明,山东省济阳县潮土表层、耕层含水量之间存在着显著的相关性,利用表层土壤光谱间接估测耕层土壤含水量是可行有效的。

Hyperspectral Indirect Estimation Model of Soil Water Content in Cultivated Layer

The objectives are to overcome the limitation that optical satellite remote sensing can only obtain the surface soil spectral information and can not be used to directly estimate the soil water content of the cultivated layer, and establish an indirect estimation model of the cultivated layer soil water content based on the surface soil spectral information. According to the soil water content and hyperspectral data of 85 tidal soil samples in Jiyang, Shandong, and the intrinsic relationship between the soil water content of the surface layer and the cultivated layer, an indirect spectral estimation model of soil water in the cultivated layer was established. The results showed that the logarithmic transformation effect of spectral reflectance of surface soil was better. With the logarithmic transformation values of 1339 nm, 1457 nm, 1745 nm, 1969 nm and 1996 nm bands as estimation factors, the determinant coefficient R ² of the surface water content estimation model established by multiple linear regression model was 0.8911 and the average relative error was 13.67%. There was a significant correlation in soil moisture content between the surface layer and the cultivated layer, and the determinant coefficient R ² between them was 0.8131. The accuracy of the indirect spectrum estimation model of soil water content in the cultivated layer was higher, the model’s determinant coefficient R ² was 0.8138 and the average relative error was 9.66%. The results indicate that there is a significant correlation between the surface and the cultivated soil water content of the tidal soil in Jiyang, Shandong, and it is feasible and effective to estimate the soil water content of the cultivated layer by using the surface soil spectrum.