INITIAL EVALUATION OF SMAP-R POLARIMETRY OVER LAND

Global Navigation Satellite System – Reflectometry has shown promising results to retrieve land-related parameters, such as soil moisture. Polarimetric radar measurements offer additional information about the scattering scenario. SMAP-R is the first polarimetric GNSS-R dataset collected from the space thanks to the reception of the Horizontal and Vertical components of an incident circular polarized signal, allowing the retrieval of the full-Stokes parameter of the reflection. The reflectivity derived from the first Stokes bistatic radar cross section is compared to the SMAP brightness temperature, showing their dependence with vegetated areas by means of a linear equation. Finally, a polarimetry analysis is conducted proposing different polarimetric ratios derived from SMAP-R Stokes parameters, and the MODIS-derived vegetation water content.