Title :
Effect of multiple scattering on the phase signature of wet subsurface structures: applications to polarimetric L- and C-band SAR
Author :
Lasne, Yannick ; Paillou, Philippe ; Ruffié, Gilles ; Crapeau, Marc
Author_Institution :
Obs. Aquitain des Sci. de l´´Univers, Floirac, France
Abstract :
We propose a two-layer integral equation model (IEM) model including multiple-scattering terms to reproduce the phase signature of buried wet structures that we observed on L-band synthetic aperture radar (SAR) images. We have good agreement between the extended (single+multiple scattering) IEM model and previous results obtained using a single-scattering IEM model combined with finite-difference time-domain simulations. We show that the multiple scattering not only significantly influences the copolarized phase difference but can also be related to the soil moisture content. In order to assess the validity of our extended model, we performed radar measurements on a natural outdoor site and showed that they could be fairly well fitted to the extended model. A parametric analysis presents the dependence of the copolarized phase difference on roughness parameters (rms height and correlation length) and radar parameters (frequency and incidence angle). Our study also shows that the phase signature should allow detection of buried wet structures down to a larger depth for C-band (3.8 m) than for L-band (2.6 m). This signature could then be used to map subsurface moisture in arid regions using polarimetric SAR systems.
Keywords :
finite difference time-domain analysis; ground penetrating radar; hydrological techniques; hydrology; moisture; remote sensing by radar; synthetic aperture radar; 2.6 m; 3.8 m; copolarized phase difference; correlation length; finite difference time domain; incidence angle; integral equation model; multiple scattering; phase signature; polarimetric C-band SAR; polarimetric L-band SAR; radar frequency; radar parameters; rms height; roughness parameters; soil moisture content; synthetic aperture radar; wet subsurface structures; Finite difference methods; Integral equations; L-band; Performance evaluation; Radar measurements; Radar polarimetry; Radar scattering; Soil moisture; Synthetic aperture radar; Time domain analysis; Finite difference time domain (FDTD); integral equation model (IEM); moisture; multiple scattering; phase; polarimetry; subsurface; synthetic aperture radar (SAR);
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2005.851180