主被动微波遥感联合的土壤水分概率反演方法研究

The significant roles of soil moisture in investigating surface earth system science and eco-hydrological process have been well recognized. The soil moisture retrieval algorithm based on the combination of active with passive microwave remote sensing is a hotpot of the research. Developing a new combined inversion strategy to fully exert the advantages of active/passive microwave remote sensing observations and quantifying the uncertainty of the inversion are the two key issues to be solved. To address these issues, this proposal is to develop a probabilistic inversion based on the combination of active with passive microwave remote sensing for soil moisture estimation. The main contents will cover the obtaining of same scale active and passive observations using ground based scatterometer and radiometer, development of a new combined probabilistic inversion based on Bayesian theorem. The main objective is to quantity the uncertainty in soil moisture inversion, as well as to provide insight into improvement of soil moisture estimation.

土壤水分在表层地球系统科学及生态水文过程研究中的重要性已得到了科学界的共识。基于主被动微波遥感联合的土壤水分反演方法是当前的研究热点。针对当前联合反演算法中亟待解决的两个关键科学问题：1）发展新的联合反演策略以充分发挥主、被动微波观测的优势，2）量化联合反演的不确定性，本项目拟以地基微波散射及辐射观测试验为基础，获取相同尺度上的主被动微波观测数据，结合贝叶斯概率反演理论，发展新的主被动微波遥感联合概率反演方法，量化不确定性，提高土壤水分的反演精度，为改进土壤水分主被动微波遥感联合反演算法提供新的思路。

微波遥感反演是进行全球和区域尺度上土壤水分监测最具潜力的方法，而主被动微波遥感联合反演更是当前的研究热点。本项目针对当前联合反演方法中的联合策略和不确定性量化问题开展了系统的探索。主要研究内容包括：1）开展了地基微波遥感试验，并在此基础上开展了微波辐射模型和介电常数模型的验证；2）系统评估了9个微波散射模型，量化了模型的不确定性；3）开展了基于主动微波和光学遥感数据联合的土壤水分反演；4）发展了基于航空被动微波遥感的土壤水分概率反演方法；5）发展了主被动微波遥感联合的土壤水分概率反演方法。项目在联合反演策略和不确定性量化方面取得了阶段性创新成果，完成了既定目标。本项目的研究结果对未来主被动微波遥感联合反演土壤水分方法的改进具有一定的借鉴意义和参考价值。