ANNOUNCEMENTS
A polarimetric synthetic aperture radar (PolSAR) based approach is used for deriving the volumetric soil moisture percentages in the southern polar region of the moon. Synthetic Aperture Radar (SAR) data taken from the Dual Frequency Synthetic Aperture Radar (DFSAR) sensor onboard Lunar Orbiter of the Chandrayaan-2 mission has been used for polarimetric analysis of the lunar surface. Chandrayaan-2 DFSAR captures data in a fully polarimetric mode at L-band which provides full polarimetric information of the moon’s surface. A subset of the data covering parts of the southern polar region is utilized for the analysis. The data was first pre-processed and then converted in the coherency matrix form which is further rotated to prevent overestimation of volume scattering during decomposition, the coherency matrix was rotated using an orientation angle. Yamaguchi model based four component decomposition algorithm was used for getting the total surface scattering as a linear combination of its scattering components (surface, volume, dihedral and helix scattering) (Verma, 2012). The surface scattering component has been inverted into dielectric constant values of the soil surface using the Bragg scattering variables which are calculated from the power scattering surface scattering component derived by the model based decomposition. These variables are minimized using their model based counterparts for optimal inversion of dielectric constant values. Further the dielectric constant was inverted into volumetric soil moisture using a predetermined polynomial conversion equation given by (Jagdhuber, 2012) (Topp, Resource and Canada, 1980).
The methodology was suitable for volumetric soil moisture estimation using the L-band data. Soil moisture percentages between 0 and 40 were obtained throughout the study region. However, no visible soil moisture distribution patterns were noticed and the pixels bearing soil moisture values were dispersed in the area of interest.
