3-D characterization of Arctic lake ice with polarimetric SAR tomography at X- and C-band

Abstract. This study investigates for the first time the three-dimensional structure of Arctic lake ice based on tomographic reconstruction from a polarimetric, multi-baseline airborne  Synthetic Aperture Radar (SAR) data set. The tomographic reconstruction indicates the presence of two strong interfaces at both X- and C-band, which can be attributed, based on field observations, to the air/ice and ice/liquid water interfaces. This means that the tomographic reconstruction is sensitive to the thickness of the ice layer of the investigated lakes. The reconstructed vertical reflectivity profiles are found to vary with polarization, therefore they can only be interpreted with a dedicated polarimetric analysis. In some lakes, we observe regions characterized by scattering with high entropy focused at the ice/water interface. We propose several hypotheses regarding the physical origin of these regions. Finally, requirements for the estimation of lake ice thickness from multi-baseline SAR are formulated to support the planning of future spaceborne SAR missions with tomographic capabilities.