Retrieval of Soil Moisture under Vegetation Using Polarimetric Radar

The unique contributions of this thesis are: 1) a polarimetric classification algorithm that is a significant improvement over an existing algorithm and 2) introduction of a cube technique to retrieve soil moisture under vegetation. The most widely used classification algorithm is the three-component scattering technique. Even though it includes three dominant scattering mechanisms, the decomposition approach can cause a non-physical solution due to incorrect assumptions. The Adaptive Non Negative Eigenvalue Decomposition approach in this thesis produces correct solution. It appears that this new approach provides better classification results. It is a significant improvement over the existing technique. A cube technique is introduced to retrieve soil moisture under vegetation. Using this approach, we have evaluated the retrieval accuracy of several polarimetric combinations. The effects of the incorrect vegetation model and data noise were investigated. In addition, the proposed cube algorithm can be improved by applying the classification result.</p

Review of the Comprehensive SAR Approach to Identify Scattering Mechanisms of Radar Backscatter from Vegetated Terrain

In a field of polarimetric synthetic aperture radar (SAR) remote sensing, various kinds of polarimetric decomposition techniques have been proposed. However, poor validations prevent them from operational applications. A true composition ratio of scattering mechanisms within a radar backscatter plays a key role. To overcome the issue, a novel comprehensive SAR approach to accurately identify a contribution of each scattering mechanism has been introduced. This is based on multiparametric SAR observation combined with a numerical model simulation. In this article, a comprehensive SAR approach is concisely reviewed to accelerate the research in this field. First, popular model-based polarimetric decompositions are introduced and their limitations are shown. Then, a behavior of scattering mechanisms is analyzed by the discrete scatterer model with some results using real multiparametric SAR data. A comprehensive SAR approach must be essential to realize an operational use of polarimetric SAR data