Soil Moisture Inversion Using Hybrid Polarimetric RISAT-1 Data

Inhalt:
Hybrid polarimetry gains strongly in interest within the SAR community due to the availability of first hybrid polarimetric data from the Indian RISAT-1 satellite for earth observation. Hybrid polarimetry outperforms dual polarimetry, for instance, regarding classification of various land cover, and is therefore also a promising technique to extract geo-physical parameters of the land surface. In this paper, a methodology based on an established compact polarimetric decomposition theorem together with a surface component inversion is investigated to invert surface soil moisture from hybrid polarimetric SAR data. The compact model-based decomposition technique is used to obtain the surface scattering component under a randomly oriented vegetation volume. After vegetation removal the surface scattering component is inverted for soil moisture by comparison with a rank-1surface scattering component described by the IEM model. The inversion results from RISAT-1 data from Karjan test site in India comprise both bare and vegetation covered soils. The first soil moisture inversion provides values in a meaningful range. The validation of results is ongoing.