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土壤中的水改变微波的介电常数，反过来受改变的介电常数又改变着微波辐射。水中的盐的含量也在某种程度上影响介电特性．当把盐水同土壤混合时，其介电特性同纯水和土壤的混合物不同．人们已开始用混合模型来描述土壤－水－空气系统。利用车载L波段和C波段微波辐射计，进行了一系列的受控条件下的现场实验，其目的是想研究出一种能够分离盐度和土壤湿度影响的数据装置．用这种数据装置估算每个变量的价值并检验拟用的混合模型。混合模型说明观测数据的趋势和取值范围；然而，盐度的观测结果同模型观测的有差异。这些差异与模型结构或现场采样有关，地表附近分布特性的变化也会引起误差。
Water in the soil changes the dielectric constant of the microwave, which in turn changes the microwave radiation by the altered dielectric constant. The amount of salt in the water also affects the dielectric properties to some extent. When salt water is mixed with soil, its dielectric properties differ from pure water and soil mixtures. People have begun to use hybrid models to describe soil-water-air systems. A series of field experiments under controlled conditions were carried out using the L-band and C-band microwave radiometers for the purpose of developing a data set that could separate salinity and soil moisture effects. Use this data set to estimate the value of each variable and test the proposed hybrid model. Mixed models illustrate trends and ranges of observed data; however, salinity observations differ from model observations. These differences are related to the structure of the model or on-site sampling, and variations in the distribution characteristics near the surface can also cause errors.