基于TM影像的荒漠-绿洲交错带土壤有机质含量反演模型

Inversion Models of Soil Organic Matter in Oasis-Desert Ecotone Based on TM Image Reflectance

选取Landsat TM影像的光谱反射率(R)、反射率之倒数(1/R)、反射率倒数之对数(lg(1/R))、反射率一阶导数(FDR)、波段深度(D)等5种光谱指标,分别建立了奇台县土壤有机质(SOM)含量的反演模型,并利用F检验来验证模型的显著性。结果表明:用各光谱指标建立的土壤各层和不同深度SOM含量的反演模型精度值由低到高的顺序均为lg(1/R)【R【1/R【FDR【D,以D反演SOM含量的模型效果最好,且对10~20cm的SOM含量的反演精度最高,适用于对研究区SOM含量的反演,FDR的反演效果次之,1/R和R的模型精度一般,而lg(1/R)的模型精度最差;各层拟合模型的反演精准度由低到高的顺序为50~60cm【40~50cm【30~40cm【20~30cm【0~10cm【10~20cm,不同深度反演模型的优劣为0~60cm【0~50cm【0~40cm【0~30cm【0~10cm【0~20cm。

The image spectrum reflectance(R),spectrum reciprocal(1/R),the logarithm of reciprocal spectrum lg(1/R),first derivative reflectance spectrum(FDR)and spectrum band depth(D)of five spectral index were selected to establish soil organic matter(SOM)inversion models,and the response characteristics of TM image of Qitai county are analyzed,the F test was used to validate the model significance.It turns out that:The accuracy value of the inversion models established by the five indicators on the soil layers and different depths SOM content are various,and the order from low to high is:lg(1/R)<R<1/R<FDR<D.The model accuracy of Dis the best for inversion of SOM content,and achieves a good standard for the monitoring of SOM content(10-20 cm).The model accuracy of FDRis good,and 1/R,Rare not good.The model accuracy of lg(1/R)is the lowest in predicting SOM content.The precision order of the soil layers models is:50-60 cm<40-50 cm<30-40 cm<20-30 cm<0-10 cm<10-20 cm,and for the different soil depths models is:0-60 cm<0-50 cm<0-40 cm<0-30 cm<0-10 cm<0-20 cm.