Snowpack characterization using SAR tomography - experimental results of the AlpSAR campaign

In this paper, we present experimental results of 3D characterization of snowpack layers using Ground Based SAR (GB-SAR) data. The data have been acquired using a GB-SAR system operating at X and Ku frequency bands. We process the acquired data using the Back Projection Algorithm (BPA). The results of this processing show strong backscattering contributions from interfaces between different layers of the snowpack. We notice also geometrical distortions due to the assumption of free space propagation medium during the processing. We introduce in this paper a correction process in order to recover the true thickness of snow layers and the corresponding refractive indexes. The obtained results are discussed according to the in situ measurement relating grain size, density and snow particle shapes description at different depths of the snowpack.