3D imaging of an alpine glacier: Signal processing of data from the AlpTomoSAR campaign

The ESA field experiment AlpTomoSAR has been planned to investigate the capabilities and potential of L-Band Synthetic Aperture Radar Tomography (TomoSAR) for studying the internal structures of glaciers and ice sheets. The scientific interest in this activity is motivated by the need for improved observations of snow and ice, which are relevant to climate researches and water management. TomoSAR represents today a new potential tool to obtain significant improvements in the capability to characterize natural media from remotely sensed data, providing 3D resolution capabilities of the imaged media. In this paper we present a tomographic analysis of the Mittelbergferner glacier, illuminated during AlpTomoSAR by flying repeatedly along an oval-like racetrack. 3D Single Look Complex cubes were focused for two opposite views by jointly processing all passes in the 3D space, resulting in a spatial resolution cell of about 2 m in all directions. The 3D data cubes were used as a basis for further physical analyses, revealing the presence of scattering elements at few tens of meters below the ice/snow interface.