中文摘要：

基于ENVISAT ASAR-APP数据,利用AIEM（改进积分方程模型）模拟分析粗糙度、土壤水分对ASAR 7个入射角后向散射系数的影响。建立小入射角模式ASAR数据后向散射模型和组合粗糙度计算模型,提出小入射角模式下双极化ASAR数据土壤水分反演半经验模型。基于AIEM模拟数据进行试验,验证了该模型的合理性,且反演的土壤水分和实测土壤水分相关系数为0.92,均方根误差（RMSE）为3.98%。

英文摘要：

Soil moisture content（SMC） is very import for agricultural,meteorological and hydrological research.In this paper,both the relationships between soil backscatter and SMC,surface roughness were analyzed using AIEM（Advance Integral Equation Model）.The bare soil backscatter model and surface roughness model were built.Then,a semi-empirical soil moisture inversion model was put forward based on dual-polarized of low-angle ASAR（Advanced Synthetic Aperture Radar） data.Soil moisture content was estimated by the model using simulation data,and the results showed that this model is reliable.The semi-empirical model has been applied to the ASAR data,a good agreement was observed between the estimated and measured volumetric soil moisture.The correlation coefficient is 0.92,and the estimation precision reaches 3.98% in root mean square error.