以修正的Dobson介电常数模型作为基础模型,分析并验证了土壤体积含水量和含盐量与介电常数的关系。在此基础上,提取不同极化方式下的雷达影像后向散射系数,分析后向散射系数与介电常数之间的关系。结果表明:体积含水量和含盐量是土壤介电常数的主要影响因素;体积含水量是介电常数实部的决定性因素,直接决定土壤介电常数实部的大小;介电常数虚部受多种因素的影响,含盐量为主要因素;体积含水量和含盐量相互作用,共同影响后向散射系数;在交叉极化模式下,介电常数是影响雷达影像后向散射系数的主要因素。基于土壤的介电常数来监测土壤中的含盐量和体积含水量具有一定的潜力,通过雷达影像反演土壤中的含盐量是完全可能的。 Based on the modified Dobson dielectric constant model, the relationship between soil volumetric water content and salinity and dielectric constant was analyzed and verified. Based on this, the backscattering coefficients of radar images under different polarizations are extracted and the relationship between backscattering coefficients and dielectric constant is analyzed. The results showed that the volumetric water content and salt content were the main factors affecting the soil dielectric constant. The volumetric water content was the decisive factor in the real part of the dielectric constant, which directly determined the real part of soil permittivity. The imaginary part of the permittivity The influences of many factors and salt content are the main factors. The interaction between volumetric water content and salt content affects the backscatter coefficient together. In the cross-polarization mode, the dielectric constant is the main factor affecting the backscatter coefficient of the radar image factor. Monitoring soil salinity and volumetric water content based on the permittivity of soil has some potential and it is entirely possible to invert the salinity of soil by radar imagery.