Integration of radar sounder and altimeter data for the 3D reconstruction of ice sheets

Abstract

The rise in global temperature accelerates the melting of the ice sheets. This highlights the importance of understanding the ice sheet structure and dynamics. Although fundamental for a reliable 3D modeling of the ice subsurface, the development of automatic techniques for the integration of multisensor data acquired over the ice sheets is still very limited. To address this issue, in this paper we present an automatic technique that integrates two types of data, i.e., radargrams (vertical profiles of the ice) acquired by airborne radar sounder (RS) instruments and ice surface elevation data recorded by altimeter (ALT) instruments. The aim of the technique is to perform a 3D reconstruction of the ice sheet by estimating maps of the surface, bedrock and ice thickness at the best possible reliable scale. Initially, the estimations of both the surface map and the related uncertainty intervals are done at several different scales by geostatistically interpolating information extracted from the RS data. Afterwards, a validation of the interpolation results and the identification of the best interpolation scale are performed by integrating the ALT data. The best scale is then used to estimate the bedrock elevation map, following the same interpolation scheme used for the estimation of the surface elevation map. Finally, the ice thickness map is computed by subtraction. The method has been applied to a subset of RS and ALT data acquired over a portion of the Byrd Glacier in Antarctica.